Volume 54 Number 1 January to March 2019

Sights in the Charioteer

The magazine of the Irish Astronomical Society [email protected] www.irishastrosoc.org

Contents

A brief history of Black Holes by David Taylor page 3 A to outshine Sirius by Michael McCreary page 5 A crawl around the Crab page 6 Sky notes for January to March 2019 by James O’Connor page 8 90 with the C-90 by Kevin Berwick page 10 How Uranus got its tilt page 12 Observers’ Corner by Aubrey Glazier page 13

On the cover Committee President: vacant Derek Buckley produced this truly amazing image of the Tadpole Vice-President: John Dolan (IC 410) in Auriga. The “Tadpoles” are the two bright linear fea- Secretary: Michael Grehan tures embedded towards the right edge of the nebula in this view. IC Treasurer: Val Dunne 410 is 12,000 light distant and spans 100 light years across. We can also: Mick McCreary, Greg Coyle, also see the open NGC 1893 within Derek’s image. Frank Boughton, Ben Emmett, John F

Formed in the interstellar cloud a mere 4 million years ago, the in- Other Society Officers tensely hot, bright cluster energize the glowing gas. Composed of denser cooler gas and dust, the tadpoles are around 10 light-years long. Observations: Aubrey Glazier Sky-High Editor: John O'Neill Instruments used were a Takahashi 106 apochromatic refractor on an Webmasters: Sara Beck John O'Neill EM 200 Tak mount and Atik 383L camera. 5 min subs/Hydrogen Alpha. Editor: John Flannery

IAS meetings and other events of interest

Next IAS meetings 2019 marks the 50th anniversary of David Bowie’s Venue for all our lecture meetings is Ely House, 8 seminal album “Space Oddity” and also of Apollo 11 Ely Place, Dublin 2. All welcome & admission is free. landing on the Moon. As a result, this ’s Dublin Bowie Festival (7th - 13th Jan) is themed around • Monday, Jan 28th at 8pm: Speaker details and space and the IAS has been invited to participate with lecture topic will be notified to members by email. Sidewalk Astronomy on the Festival’s last weekend and a day of science at The Phoenix Park Visitors Centre on Monday, Feb 25th at 8pm: Speaker details and • Sunday, Jan 13th. See www.dublinbowiefestival.ie lecture topic will be notified to members by email. • Monday, Mar 25th at 8pm: Speaker details and This year’s BT Young Scientist Exhibition runs from

lecture topic will be notified to members by email. Jan 9th to 12th in the RDS. See btyoungscientist.com for the timetable and admission details.

Dublin Sidewalk Astronomers Galway Astronomy Club’s annual Festival is on Jan Friday, Jan 11th at 8pm: The Dublin Sidewalk As- 26th this year in the Harbour Hotel in the heart of the tronomers meet at the car park, on Strand Road, just city. As well as a full day of talks there will be trade south of the Sandymount Martello Tower, Dublin 4. stands and an exhibition. Speakers include: Aaron Free, all welcome. Golden of NUIG; Tony O’Hanlon; Mike Baille, QUB; Morgan Fraser, UCD; and Sophie Murray, TCD. Tom Saturday, Jan 12th at 8pm: The Dublin Sidewalk O’Donoghue will host an astrophotography workshop. Astronomers meet in Clontarf. The venue is the sea- front car park, on Clontarf Road, opposite the Clon- The Royal Irish Academy’s McCrea Lecture on Feb tarf Bus Garage, Dublin 3. Free, all welcome. 7th is “The European Southern Observatory in 2019, See our web site for details of further DSA events and the evolution of as probed by ALMA” and held monthly in each alternate venue (Sandymount on is given by Rob Ivison, ESO’s Director of Science. More Fridays and Clontarf on Saturdays). details and booking can be found at www.ria.ie

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A brief history of Black Holes

by David Taylor

HORTLY AFTER Einstein’s General theory of rela- act with each other. Excitations of these fields can be S tivity was published, a curiosity was found by Karl represented as the familiar point particle theory. Schwarzschild. A stable solution was found that There is a specific aspect of quantum theory that is seemed to describe a most peculiar object (one that needed here, that is the notion of particle creation was briefly thought about in the late eighteenth cen- and annihilation. The hypothesis goes that particles tury). It was an object that warped the fabric of can flit in and out of existence subject to certain con- space and time in such a way that nothing could es- ditions. One is that the particles that are created cape. Thus the “black hole” as we know it was con- must be a pair such that one is a particle and the ceived. This is the classic idea of a black hole; an ob- other is its antiparticle. They get created, live a short ject of fixed size, with a huge gravitational well. At life, and annihilate with one another. its centre, the singularity, a point of infinite density, which itself is surrounded by the event horizon; the It is worth noting by the way that the marriage of boundary of no return. We'll call this type of black general relativity and quantum field theory is the holy grail of theoretical physics. There have been many hole a classical black hole. attempts; string theory, loop quantum gravity, to While at the time thought too extreme to exist, name but two. The difficulty arises from the funda- the idea persisted, and many years later astronomers mental differences between the two frameworks: In noticed that the motions of certain clusters of stars at general relativity, spacetime is assumed to be a con- the centre of galaxies were moving with incredible tinuous manifold, whereas in QFT, the more we zoom speeds around a seemingly invisible centre! That is, in the more granular the universe appears to be, to there was some massive object which wasn’t emitting the point that right at the lowest level it is hypothe- any light, yet interacting with these nearby stars via sised to be a quantum frenzy of madness. In this re- gravitation. They determined that the mass required gime nothing of our usual aspects of the universe are to cause the stars to orbit as they were was vastly familiar. The result of this is that when we incorpo- more than even the most massive stars. This was a rate the equations of quantum mechanics into general serious candidate for a black hole. relativity, the equations “blow up”, that is they give nonsensical answers such as infinite probabilities. With more and more observations like this, the Thus, Hawking's attempt at a slight overlap of the idea of black holes existing in our universe was be- quantum realm in a gravitational setting is a spec- coming generally accepted by the scientific commu- tacular result. nity. Few concepts have captured the imagination quite like these fantastic objects with such little ob- Radiation Revelations servational facts. There is somewhat limited scientific evidence of these objects, nevertheless much re- Now that we’re better equipped, let’s see what search has been done on the mathematical objects Hawking achieved. He placed the idea of the black which has modified our version of the classical black hole in this quantum framework, one where our parti- hole many times and in many ways. cle antiparticle pairs live. If we zoom into the bound- ary of the black hole, the event horizon, we have this Taking Quantum Leaps sphere of no return, so if we have particles and anti- particles coming in and out of existence right at the With the advent of quantum field theory, certain boundary, antiparticles can fall into the black hole, aspects of the black hole needed thinking about. One while the particle (without it’s partner to annihilate surprising (almost paradoxical) result is that a black with), can escape to infinity. Seen from far enough hole, an object where nothing can escape, should in away, it would appear that the black hole is in fact fact radiate! This amazing feat of thought was devel- radiating! This amazing result was named in Hawk- oped by the late great Professor Stephen Hawking. ing’s honour; Hawking radiation. The temperatures The father of popularising these ideas and making were calculated to be quite less than the balmy 3 kel- them accessible to a general audience via his many vin of the cosmic microwave background radiation, so best-selling popular science books. measuring this is currently practically impossible. A To understand his revolutionary contribution, a consequence of Hawking radiation is that the antipar- little quantum field theory (QFT) is necessary. In QFT, ticle diet of the black hole causes it to shrink in size! the most fundamental physical entities are not point So over time it would appear that the black hole particles; they are fields. In this framework, the uni- evaporates. We have now moved away from the clas- verse is filled with these quantum fields which inter- sical black hole to this quantum black hole.

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Going back for a moment, the fundamental princi- dynamic system can have when in a state as specified ple of quantum mechanics is that all the information by some macroscopic variables. It also comes up in of a system is embodied by its wave function; which information theory as the disorder of a system. cannot be destroyed. This has relevance to us here when speaking about black holes. Particularly where a If we are comfortable with the idea that wave black hole has evaporated to nothing. Is this possible? functions falling into black holes have their informa- What happens to the wave functions of the matter tion encoded onto the boundary, then it makes sense that fell in through the event horizon? “The informa- to talk about a black hole’s entropy. “Entropy”, tion paradox” as it is known has plagued physicists “radiation”, “evaporation” are all thermodynamic and cosmologists for decades. For thirty years Hawk- quantities, what are they doing in black hole physics? ing firmly claimed that information can indeed be de- The information paradox itself arises from the second stroyed in a black hole, without any convincing oppos- law of thermodynamics not being violated, and there ing theories at demonstrating otherwise. Until in are in fact a set of equations for black hole dynamics 2004, a potential solution came via the holographic that are equivalent to the equations of thermodynam- principle. This forced Hawking to reconsider, and con- ics! cede that black hole evaporation may preserve infor- mation. I could (and may) dedicate a whole article on Firewall Problems the holographic principle, but the underlying postu- It has been suggested by Polchinski et al. that in- late is that the information of an n-dimensional object formation leaving a black hole during evaporation can be encoded into an n-1-dimensional object. What would cause a "firewall paradox”, that is, the process this means is that the information falling into a black would produce a huge amount of energy creating a hole could be preserved and encoded on its boundary, wall of plasma around the event horizon destroying the event horizon, thus potentially solving the infor- any in-falling matter. This forces a contradiction of mation paradox of an evaporating black hole. the principle of equivalence in general relativity, i.e. that there should be no distinction to an observer fal- An Aside on Thermodynamics ling through the event horizon. A possible reconcilia- When we start talking about “information” in phys- tion proposed by Hawking is that of an “apparent hori- ics, the concept of “entropy” is never far behind. En- zon”. It is a hypothesized surface that traps light but tropy has a few, equivalent definitions: It arose first which can also vary in shape due to quantum fluctua- in the thermodynamic “heat engines” of the industrial tions. This is enough to allow the potential for light revolution as a measure of the unavailable work in a (and thus information) to escape. system. In statistical mechanics, it is related to the Sir Roger Penrose previously used general relativity number of microscopic configurations that a thermo- to show the equivalence between event horizons and

Stephen Hawking’s proposed solution to the “Firewall Paradox”

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apparent horizons. This is a good step, as classical empty space can perhaps carry information. More spe- phenomena can be distilled from quantum ones as the cifically, they propose that soft particles are at work. quantum numbers (usually Planck's constant h) ap- These particles can exist in a zero energy state, proach zero. In a more recent paper, Penrose suggests hence, particles falling into a black hole would leave that quantum mechanics might reveal the horizons to information behind with them. Hawking et at. suggest be different. Removal of the event horizon removes a mechanism to do this but they have yet to explain the firewall paradox. This would imply that informa- how the information exchange would actually occur. tion is lost. However, Hawking suggests that need not The information transfer mechanism has been called be the case. Hawking proposes that the structure of a “black hole (soft) hair”. This term they came up with black hole just below the horizon is chaotic. That is, to describe calculations that showed encoding data in the information is practically impossible to interpret, quantum descriptions of the event horizon. but importantly, not destroyed. There is a lot of skep- ticism with Hawking’s suggestion. His interestingly Recap and Conclusions titled paper: "Information Preservation and Weather Forecasting for Black Holes", is quite sparse, short, What started off as a curious solution to Einstein’s and contains no calculations. Polchinski suggests that field equations, has lead us down the path of the truly Hawking is replacing the firewall with a “chaos-wall”. bizarre: From hypothetical monsters, to convincing observations, to holograms and information para- In January 2016, Hawking, Perry, and Strominger doxes! Black holes are truly fantastic creatures that published a paper attempting to resolve the informa- continue to capture the imagination of academics and tion paradox in a new way. Their suggestion is that amateurs alike.

A star to outshine Sirius

by Michael McCreary

On a recent trip to Queensland, Australia, to visit stellation of Carina and second-brightest in the night new grandchildren I realised my holiday was very sky, on which I will come back to this later. It has a badly timed from astronomical point of view as it was visual magnitude of -0.74 and an the start of their Summer, and the Moon was a waxing of -5.71. It is a bright giant of spectral type A9, white crescent when I arrived. The trip was not about as- in colour to the naked eye, 310 light years from earth tronomy though but I did plan to meet up with the and a mass eight times that of the Sun. The surface Astronomical Society of Townsville at one their side- temperature is 6,998K and the star rotates at 8km/s walk events. at its equator. Canopus has a radius 71 times that of our Sun which means if placed in the middle of our The event was timed to start at 7pm but I did not solar system its surface would nearly reach the planet arrive till 8pm so I missed them, and their next event Mercury. It is also over TEN THOUSAND times more was cancelled because of cloud. I did manage to do luminous than our Sun. It is a massive giant star on some observing with my son’s small 70mm refractor the H-R diagram. telescope at a dark sky park site 20km outside Towns- ville, but was not impressed when my son said, "Keep Canopus was once the brightest star in Earth's an eye out for SNAKES”! night sky and during our journey around the MILKY WAY our paths were closer at three different times in It was weird to see the of Orion up- the last four million years. About 90.000 years ago side down and it took a while to get my bearings. The Sirius moved close enough that it became brighter planets Mars and Saturn were easy to find but the than Canopus and it will remain so for 210,000 years. view of Venus in the early morning was brilliant. Then in 480,000 years Canopus will once more be the One star stood out to me more than any other, brightest star in our night sky for another 510,000 having at first mistaken it for Sirius early in the eve- years. ning. In ancient times Canopus, just like Sirius, was seen That star is CANOPUS in the constellation of Carina as a God or omen to different cultures from the Maori (not visible from Ireland) so I made a mental note to of New Zealand, the Polynesians, the Chinese, Bed- find out more about it when I returned home. I was ouin, the Navajo from southern USA - even the an- quite surprised that Canopus only got a short mention cient Egyptians culture had different names for in my Burnham's Celestial Handbook. I delved a bit CANOPUS. Many of them used it like a southern pole deeper and found the following: star. In fact the effects of precession will take Canopus within 10 degrees of the South Celestial Pole Canopus is the brightest star in the southern con- around the year 14,000.

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A crawl around the Crab by Gareth Flynn

the . The key to the survival of M67, however, lies in its own orbit that brings it to a great distance (1,500 light years) high above the plane of the Milky Some time back I did a spot of observing with my Way. 15x70mm binoculars. It was also an opportunity to re- The vast majority of open star clusters are spawned acquaint myself with some of the familiar celestial amongst the great clouds of gas and dust that are con- sights after a few months of little observational activity. centrated within a few hundred light years of the galac- Nestled between more prominent Gemini and Leo tic plane. M67, on the other hand, is well removed from is the zodiacal constellation of Cancer, the Crab. its original nursery as its orbit takes it high above the Though dim, and literally a footnote in the legend of disk leading to less frequent adverse encounters with Hercules (the mythological strongman crushed the hap- its kin. The age of the cluster's stars is similar to that of less crab underfoot during his battle with the multi- our Sun and, indeed, its members happen to have a headed Hydra), Cancer nevertheless holds a number of similar chemical composition as the Sun. delightful objects for the binocular user. The Crab's pat- One of the most celebrated objects in the sky is tern is not readily apparent at first but from a dark site Praesepe, or M44, the Beehive star duster. It is visible you will begin to trace the Crab's outline as just two to the naked-eye as a spot of light framed by δ, γ, η, stars are above fourth magnitude. and φ Cancri, making up the "body" of the Crab. The The brightest is β Cancri (+3.59), or Al Tarf ("the proper names for γ and δ Cancri - Asellus Borealis and End"), an orange giant that is estimated to be fifty times Asellus Australis - come to us from Greek myth where the diameter of our Sun. It is also a double, although they represented the donkeys on which the gods Dio- the fourteenth magnitude companion is well beyond the nysos and Silenus rode into battle against the Titans, range of binoculars. The physical separation between who were so frightened by the animals' braying that the the two is quite large - on the order of 2,600 astronomi- gods won. As a reward, the asses were put in sky to- cal units - while their is reckoned to be gether with the manger - presumably to ensure a per- about 76,000 years! petual supply of hay! α Cancri, (+4.25), or Acubens ("the Claw"), is But before having a peek at the group, stop briefly ranked only the fourth brightest star in the Crab and is at X Cancri, a dun-hued semi-regular variable that lies a pure white sun of spectral class A. Interestingly 2¾° east-southeast of δ Cancri. The period is 195 days enough, it is a tight spectroscopic double with both and the brightness fluctuates between magnitude +5.6 stars of equal separated by just 5 astronomi- and +7.5. A handful of sixth and seventh magnitude cal units. The presence of a nearby faint twelfth magni- stars are sprinkled across the field. tude red-dwarf companion that is itself a double makes Praesepe, or Phatne (the Manger), has been known for a rather interesting quadruple system. since ancient times and the first recorded mention of it Acubens is also the jumping off point for our venture is in the great weather and sky lore poem Phaenomena into deeper space to find the ancient galactic cluster, by the Greek author Aratus who wrote in 260 BC: M67. Keeping the star towards the left (eastern) edge of the field of view in the binoculars, the duster is seen "And when with deep-charged clouds the air's opprest, as an elongated mottled haze about two degrees to the Phatne, the spot that shines on Cancers breast, west. On my second evening out observing the area I Attentive mark: if bright the spot appear, Soon Phoe- was able to see a sprinkling of the brighter 9th magni- bus smiles with face serene and dear, tude members of this association while an unrelated 8th magnitude sun lay just outside the northern edge of Nor the returning rain and tempest fear." the group. Indeed, the visibility of the cluster with the naked M67 is considered to be one of the oldest galactic eye has long been regarded in folklore as an indication dusters known, with an estimated age of four billion of weather conditions. Although the sky transparency years. This poses the question as to how its members was not that good on the two nights I ventured out, have remained gravitationally-bound over such a long Praesepe was clearly visible without optical aid but I period of time. Most open star dusters are disrupted have seen it more distinctly on occasions. It was not after a few hundred million years following encounters until Galileo turned his telescope skyward though, that with other clusters or by successive passages through the true nature of the Beehive became apparent; "The giant interstellar gas clouds during their circuits around nebula called Praesepe, which is not one star only, but a mass of more than 40 small stars."

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Binoculars are the ideal instrument to examine this and associations. sprawling cluster and to resolve the stars swarming Taking our leave from M44, we now head north- around an imaginary celestial honey pot. The brightest wards to the beautiful double star, ι Cancri. The separa- member of the group is ε Cancri, a +6.3 magnitude star tion is 31" and the magnitude +4.2 primary appears that is 70 times as luminous as the Sun. If we could yellowish with the magnitude +6.6 companion glowing place our Sun in the midst of M44, it would appear as a bluish-white. The star is set in a lovely field that shows feeble magnitude +10.5 spark of light as seen from two nice curving chains of stars tapering to a point. Earth. Again, I teased out a miniature constellation shape; this I made no effort to count the number of visible mem- time the pattern partly reminded me of a diminutive bers, as I was more intent on finding two doubles that Perseus. Another nice star field is centred on the line of reside within its boundaries - ADS 6915 (Burnham 584) a stars, tagged 1 through 4, from west to east. We fin- and ADS 6921 (see chart of M44). Both lie towards the ish our tour, though, with the rather unassuming 55 southern edge of the cluster as part of a sort of tipped- Cancri - a sixth-magnitude sun that is also labeled ρ1 over "house"-shaped asterism that also reminded me of on charts. The star is a member of the exclusive club of a miniature Cepheus. those stars found to posses a . Only one attendant planet is known at present though a sec- ADS 6915 is a triplet of suns of around seventh ond more massive body is suspected in the data. magnitude at the "roof" of the "house" with the star right at the apex of the triangular arrangement being bright- The confirmed extra-solar planet its parent in est. ADS 6921 is a quadruple system but only the two only 14.6 days at a distance of 16.5 million kilometres - more luminous members will be seen in binoculars. A or 28% the distance of Mercury's orbit from the Sun. fifth-magnitude satellite that sped through the field as I The mass is slightly less than that of Jupiter. 55 Cancri was observing was a nice bonus. is a G-type dwarf slightly cooler than the Sun and is 41 light years away. Recent measurements place M44 at a distance of 577 light years with the cluster's age estimated to be Before I packed up on the second night to head about 400 million years. This fixes it at the same age home I took a moment to reflect on how the tour of and distance as the equally well-known Hyades in Tau- Cancer ranged from doubles to clusters, stellar evolu- rus and has led astronomers to believe that both tion to the cutting edge of research on extra-solar plan- groups were born in the same area of space long ago. ets, and finally, to the human connection with the skies A third member of the so-called Hyades superduster is above. We may have gazed at the night sky countless NGC 1901 in the southern constellation of Dorado. The times, but when we become aware of the stories be- whole subject of galactic superdusters (as distinct from hind the sights, then we ourselves - and our hobby - galaxy superclusters) offers a fascinating insight into are that bit richer.

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Sky notes for January to March 2019

by James O’Connor

The Sun, having passed the point of Winter Solstice (23.4° S) on Dec. 21, is now moving steadily northwards again. It crosses the Celestial Equator at 22h on March 20, when day and night will be of equal duration throughout the world. Perihelion (Earth closest to sun at 147 million km.) is on January 3. Many people are surprised at how quickly the evenings lengthen in January. They don’t realize that they have, in fact, been lengthening since the previous December 13. This is due to an effect known as the Equation of Time, which I haven’t space to explain here. By way of counterbalance, the mornings continue to darken until the end of December, i. e., until well after the date of the winter solstice. The sun’s N Pole is tilted away from Earth throughout the period, by 3.0° on January 1, increasing to 7.3° by early March and reducing to 6.6° by the end of that month. The N end of the axis of rotation slopes 2° to- wards the east on January 1; this changes to a slope of 26° towards the west by the end of March. Partial Eclipse of Sun: A partial eclipse of the sun on January 6 will not be visible here.

The Moon

New Jan. 6d 01h 29m Feb. 4d 21h 05m Mar. 6d 16h 05m First Quarter Jan. 14 06 47 Feb. 12 22 27 Mar. 14 10 28 Full Jan. 21 05 17 Feb. 19 15 55 Mar. 21 01 44 Last Quarter Jan. 27 21 11 Feb. 26 11 29 Mar. 28 04 11

Lunar Perigee is on January 21 at 20h, February 19 at 09h and March 19 at 20h. Lunar Apogee is on January 9 at 04h, February 5 at 09h and March 4 at 11h. Libration maxima: Jan 15.23d (10.1° in PA 29°); Jan 27.72d (10.1° in PA 247°); Feb 12.06d (9.9° in PA 32°); Feb 24.63d (9.9° in PA 247°); Mar 11.39d (9.1° in PA 29°); Mar 24.48d (9.0° in PA 244°). Libration minima: Jan 7.58d (1.2° in PA 298°); Jan 21.52d (1.4° in PA 153°); Feb 4.13d (1.8° in PA 299°); Feb 18.62d (2.8° in PA 158°); Mar 3.71d (2.4° in PA 300°); Mar 18.44d (3.9° in PA 158°).

Total Eclipse of Moon A total eclipse of the moon occurs in the morning hours of January 21. The penumbral phase begins at 02:36 and ends at 07:48; the partial phase begins at 03:34 and ends at 06:51; totality begins at 04:41 and ends at 05:43.

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The Planets

Mercury will be unfavourably placed for viewing the end of March. for most of the quarter but a window of opportunity Its stellar magnitude declines in tandem with this arises in the second half of February, when the planet will be fairly well placed for viewing in the – from +0.4 to +1.4. western evening sky. Look for a star-like object very Jupiter, which passed conjunction in late Novem- low in the western sky about three-quarters of an ber 2018, is located in Ophiuchus at magnitude -2.1. hour after sundown, over the spot where the sun has Its separation from the sun in the morning sky contin- disappeared. The stellar magnitude of the planet is ues to increase but its low of 22°S will -1.1 on February 16, declining to -0.5 on February 26 tend to hamper observation. but its position low in a twilit sky will make it appear Saturn is in conjunction with the sun in Sagitta- much fainter than these figures suggest. rius on January 2 and thereafter emerges slowly from Venus continues as a bright object in the south- the solar glare. By the end of March it will be rising eastern morning sky but the length of time between about three hours before the sun but, as in the case its rising and that of the sun reduces steadily from of Jupiter, its low declination will hamper observa- four hours on January 1 to one hour on March 31. tion. Its stellar magnitude is 0.6. This arises mainly from its changing to a position well Uranus (mag. 6), in Pisces, may be observed in south of the sun. Its stellar magnitude reduces only the southwestern evening sky throughout the period slightly – from -4.5 to -4.0 – during the same period. but the nightly observation window reduces gradually Its apparent angular diameter reduces from 28” to as the planet closes in on the sun; it disappears into 13”, while its phase increases from 44% illuminated the solar glare in early April. On January 1, it is lo- to 80% illuminated. cated 1.5° north of the 4.5 magnitude star 110 o Pis- Mars remains visible in the evening sky throughout cium. Its movement is direct. the period as it moves rapidly eastwards through the Neptune (mag. 8) is located in Aquarius and may of Pisces and Aries into Taurus. The be picked up in the southwestern evening sky during northerly component of its motion means that it sets January and early February. After that, it becomes at almost the same time right through the period. It lost in the solar glare. Conjunction with the sun is on apparent angular diameter declines with its increas- ing distance from Earth, getting down to just 4.7” by March 7

Meteors The important shower of the Quadrantids is predicted to reach maximum at 03h on Jan 4, with a ZHR of per- haps 80. The radiant is in northern Bootes and so this is a mainly morning-hours event. The moon will not in- terfere this year. The shower has a rather narrow peak which, as will be seen, favours places in the longitude of Ireland this year.

Variable stars Algol (β Persei): Minima are predicted for Jan 18d 0.0h, Jan. 20d 20.8h, Jan. 23d 17.6h, Feb. 7d 1.7h, Feb. 9d 22.5h, Feb. 12d 19.3h, Feb. 13d 16.0h, Mar.2d 0.2h, Mar 4d 21.1h, Mar 7d 17.9h, Mar 22d 1.9h, Mar 24d 22.8h and Mar 27d 19.6h. RW Tauri (7.6 to 11.5) : Minima of this eclipsing variable (period 2.768846 days) are predicted for Jan 11d.19h, Jan 22d 20.8h, Feb 2d, 22.7h, Feb 5d 17.0h, Feb. 16d 19.0h, Feb 27d 20.8h, Mar 10d 22.7h and Mar 13d 17.0h. Mira-type stars: The following Mira-type stars are approaching maximum: W And (Apr at mag. 7.4), X Cam (Apr at mag 8.1) W CrB (Feb/Mar at mag. 8.5), RU Her (Jan at mag. 8.0), RU Her (Jan at mag. 8.0), SS Her (Apr at mag. 9.2), X Oph (Jan/Feb at mag. 6.8) and U Ori (Apr/May at mag. 6.3). The dates and magnitudes for the Mira stars are approximate.

Lunar Occultations (at Dublin)

Date and Time Star Mag. Phase C.A.° Ill. of Moon

Feb 13d 23h 28.3m ZC 650 – 63 Tau 5.6 D 32S +60%

Cusp Angle (CA) is the angle of the event around the limb of the Moon measured from the nearest cusp. Negative values (-) indicate a bright limb event. The cusps are usually N (north) or S (south) but can be E (east) or W (west) near Full Moon.

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by Kevin Berwick

As you know, I own a small 3.5 inch Maksutov Cassegrain telescope, the Celestron C90. Here, I will continue my series on documenting my deep sky experiences from the Dublin suburbs with this tiny telescope.

I was out with my C90 on a recent clear, evening Cas, shines at magnitude 8.6 and is reddish. NGC457 is and saw six beautiful objects in quick succession. definitely one of the prettiest clusters that I have These are the subject of the latest article. seen. In the book The Caldwell Objects, Stephen James O’Meara describes the view of C13 as “The cluster’s bright ‘eyes’ seem to pierce the night with the fiery gaze of a spectre emerging from the dusty cobwebbed corridors of space. The ghost’s clothes hang in tatters from skeletal limbs “. Fantastic!

Stock 4 Stock 4 is an open cluster in Cassiopeia in the shape of a squat Russian doll. All stars in the cluster are of roughly equal brightness. A pair of eighth mag- nitude white stars form a nice double to the East. Arcturus Well worth seeking out despite the fact that it is in an obscure catalogue and might be thought of as difficult Picot 1 to see using a small aperture. French Astronomer Fulbert Picot discovered this M56 interesting seven star grouping near Arcturus in Bootes. The cluster consists of seven stars on an al- M56, a globular cluster in Lyra, is easily found us- most perfect Napoleon’s hat, or Gaussian curve if you ing β and γ as pointer stars. It consists of a small faint are mathematically inclined. It really is a remarkable circular blur and can easily be missed or mistaken for shape. The whole object easily fits within the field of a galaxy. The field around M56 is particularly rich 32 mm eyepiece since it is right in the middle of the Milky Way. M56 is part of the wonderfully named Gaia Sausage, the hy- NGC 457 pothesised remains of a merged dwarf galaxy. Located Appropriately for this season, this cluster in Cassio- 46,000 light years away, it is by far the most distant peia reminds me of the statue of ‘Christ the Re- object in Lyra within range of amateur instruments. deemer’, spectacularly perched above Rio de Janeiro. ε Lyra the Double Double in Lyra This open cluster was discovered by William Herschel in 1787. It is variously called the Running man, Skiing, This object is usually a great view in just about any ET, Dragonfly or Owl cluster. It is also Caldwell 13. I telescope, even under the most light-polluted skies. viewed this object on an evening when the full moon Though easy to find, it is surprisingly difficult to split was high in the sky. So it is clearly visible under even in the C90. Initially I tried the 32 mm low power eye- poor conditions. piece, then 20 mm, then 10 mm giving 125 X, then back to 16 mm. The best view was in the 16 mm but Unlike many clusters with fanciful names, it actu- the split was not good. I split this object in my 4 inch ally does look like an Owl. I can easily make out the refractor many times so I did know what to look for. wings, body and feet. The body is very bent. Two Honestly, even at best, I could convince myself I was eyes, with one, the slightly yellowish φ Cas, consid- seeing diffraction ring minima, rather than a hard erably brighter than the other, complete the Owl. split between components. It is quite possible, of The majority of the rest of the stars are white to my course that this is due to poor seeing. Another possi- eyes, including the other ‘eye’. One notable excep- bility might be poor optics or roughness. I have drawn tion is one of the stars constituting the ‘armpit’ in the the stars in the figure unsplit with the orientation of eastern ‘wing’ of the Owl. This star, known as V466 the doubles marked by a line.

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Interestingly, the two doubles are oriented pretty much East-West and North-South, perpendicular to each other. All 4 stars constituting the Double-Double are quite noticeably white. Remarkably, each pair is also physically connected to the other. and Stephenson 1 Delta Lyrae is a nice coloured double I overlooked until I read about it in Deep Sky Wonders by Sue French. It is an orange star while the secondary is white and fainter. It is not a true double, merely an optical double, so the paring is merely a line of sight effect. There is a group of fainter stars between that’s called Stephenson 1. That’s it for this year! Merry Christmas and clear nights to you all in 2019! The Double-Double through the C90

The naked-eye Moon by Richard Murphy

The American astronomer William H. Pickering graded from 1 to 12, in order of increasing difficulty to (1858 - 1938) was one of the more eccentric personali- make out. ties in the footnotes of astronomical history. Although The photograph below indicates the position of the he vigorously opposed the contention of Percival features on Pickering's scale and while the bright re- Lowell that there were "canals" on Mars built by beings gion splayed around the crater Copernicus is easy to on that world, he had some bizarre theories of his own see, extremely fine vision is needed to reach number regarding our own moon. 10 on the scale, the faintly shaded area near Sacrobo- One of these concerned dark spots he observed in sco. Those with exceptional visual acuity might distin- the lunar crater Eratosthenes which, he claimed in guish the 11th feature while Pickering thought that 1924, were due to enormous swarms of insects! To number 12, the Riphaeus Mountains, might be beyond back this theory up he suggested that lunar astrono- anyone’s ability. mers would have seen dark spots on the great prairie Fred Schaaf, in his book The Starry Room, sug- regions of North America caused by the huge buffalo gests extending the scale to include the dark floored herds that roamed there in the early 19th century. crater Plato as the 13th feature. To see Plato may re- Pickering made many genuine contributions to lunar quire truly exceptional eyesight however. studies though and was also the first to produce a pho- tographic atlas of the Moon showing each section of the surface under several conditions of lighting and libration. He also carried out studies on how small a feature could be made out on the Moon with the naked eye and to this end he devised a scale of features,

1.Bright region around Copernicus 2.Mare Nectaris 3.Mare Humorum 4.Bright region around Kepler 5.Gassendi region 6.Plinius region 7.Mare Vaporum 8.Lubiniezky region 9.Sinus Medii 10.Faintly shaded area near Sacrobosco 11.Dark spot at foot of Mt Huyghens 12.Riphean Mountains

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How Uranus got its tilt by Universe Today writer

A presentation at last Autumn’s American Geo- • It’s the only planet where the interior heat physical Union meeting discussed the latest findings doesn’t escape from its core. on how Uranus got flipped onto its side to give a tilt of about 98 degrees. According to detailed computer The collision that made Uranus what it is today simulations, a body about twice the size of Earth happened two or three billion years ago, but accord- slammed into Uranus between 3 to 4 billion years ago. ing to the simulation it was over in a matter of hours. The impact created an oddity in our Solar System: the The simulation shows that a body about twice the only planet that rotates on its side. size of Earth slammed into Uranus, tilting it to about The findings build on previous studies pointing to 98 degrees. The object that slammed into it was an impact as the cause of Uranus’ unique orientation. made of rock and ice, and some of that material fell Taken altogether, we’re getting a clearer picture of into Uranus’ core. According to the abstract, not all why Uranus rotates on its side compared to the other of it did, and that explains why Uranus doesn’t shed planets in our Solar System. The impact also explains heat from its core: “Furthermore, most of the impac- why Uranus is unique in other ways. tor’s ice and energy is deposited in a hot, high- When the Solar System formed, it all started with entropy shell at a radius of 3 R. This could explain a massive cloud of gas and dust. The cloud swirled as Uranus’ observed lack of heat flow from the interior… it became more dense, and eventually the Sun formed The abstract also says that this could help explain in the centre, with the rest of the gas and dust swirl- the planet’s weird magnetic field. While Earth’s mag- ing around it. The Sun contains about 99.8% of the netic field is tilted from its geographic poles by 11 mass in the Solar System, and as the remaining 0.2% degrees, Uranus’ field is tilted by 59 degrees. swirled around it, clumps began to form into the plan- ets we know today. As they formed, the rotation of The simulation also suggests that the moons of the gas cloud was imparted to the planets. So, all of Uranus formed after the collision. There was likely a the planets rotate the same way, except for Uranus, ring of debris as the result of the impact, and the (and Venus, which was likely struck by an asteroid.) moons formed from that debris. That’s why the five largest moons rotate on the same axis as the planet. The planets aren’t all exactly alike; Earth is tilted on its axis a little, giving us seasons, and so are Jupi- Uranus, and the Solar System’s other ice giant, ter, Neptune, and Saturn, to varying degrees. But Neptune, are the least studied planets in our system. they’re still oriented more or less the same as the There’ve been no dedicated missions to either planet, rest of the planets and moons. But Uranus isn’t. It’s though Voyager 2 did visit them briefly in the late tilted on its side relative to its fellow planets, by 1980s. Scientists rely on observation and computer about 98 degrees. simulation to understand them both. This latest study For years, evidence has been building that sup- builds on other evidence pointing to impacts as the ports a collision between Uranus and a body about cause of Uranus’ tilt. Once such study suggested mul- twice the size of Earth. This most recent study builds tiple impacts were responsible, but that line of evi- on that evidence. A team from Durham University ran dence hasn’t persisted. more than 50 different impact scenarios using a high- It shouldn’t be a surprise to anyone that an impact powered super computer to see if they could recreate is responsible for Uranus’ predicament. The history of the conditions that shaped the planet’s evolution. the Solar System is full of impacts. The so-called The findings confirm that the most likely outcome ‘Late Heavy Bombardment‘ about 4 billion years ago was that the young Uranus was involved in a cataclys- pelted Earth and the inner Solar System with aster- mic collision with an object twice the mass of Earth, oids. Earth’s Moon may have been created from a col- if not larger, knocking it on to its side and setting in lision between Earth and a doomed planet called process the events that helped create the planet we “Theia”. On the Moon, Venus, and other bodies we see today. can see the abundant craters caused by impacts. And, The results of the simulations explain not only Ura- of course, a massive asteroid strike here at home nus’ obliquity, but also some of its other properties: brought on the demise of the dinosaurs and changed the history of our planet forever. • Not only does Uranus rotate on its side, but so do its five largest moons. Many missions to Uranus have been proposed, but so far none have been approved. But space scientists • It’s magnetic field is also lopsided, and doesn’t are nothing if not patient. Eventually, a dedicated go out the poles. mission to this far-flung neighbour will be launched, and some of this ice-giant’s secrets will be unlocked.

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Observer’s Corner

compiled by Aubrey Glazier ([email protected])

Recently I was having a chat with one of our members of the Irish Astronomical Society regarding a very popular website for double stars. So I thought it is now high time I discuss it with you as I do use it a great deal myself –especially when I am planning to observe these wonderful objects. Simply enter www.stelledoppie.it on Google. The site is very reliable at keeping everyone up to date year after year and is a search engine to the famous Washington Double . Simply enter your user name and password (financial donations are optional). Once in, you are completely free to enter any double or multiple star in the Search box. You will then see all the important information regarding these systems and will soon discover that many doubles et al change their separations and positions every year. All these are kept up to date. Alternative designations, colours, distances, magnitudes, right ascensions, - plus whether the systems are optical or true binaries – these are all included. There is an enormous wealth of in- formation to be had on the web site. Many double star enthusiasts from www.cloudynights.com use it. I wish you all clear skies over the Christmas period and for the New Year 2019! Oh and happy hunting for Comet Wirtanen.

From James O’Connor the rapid shrinkage of the South Polar Cap as well as getting reasonable views of Syrtis Major Planum and Venus has been illuminating our morning skies adjoining dark markings. (22h – c.m. = 84º). On Sept. with extraordinary brilliance recently and will con- 23 at 20h 30m (c.m. = 202º), as well as the (still tinue doing so into the New Year. It reached magni- shrinking) SPC and the prominent North Polar Hood, I tude -4.7 in late November. At 7h on December 4, I could see Terra Sirenum, situated between the SPC estimated that it was only about one magnitude and the Equator. On Sept. 30 and Oct. 6, Syrtis Major fainter than the waning crescent moon, which at the Planum and environs were back in view (c.ms. of 126º time was about 10 degrees to its left but still three and 63º, respectively days short of new. That morning, I pointed out the two objects to a From Aubrey Glazier man waiting at the bus-stop with me and told him a I own a William Optics 158 mm f/7 apochromatic few facts about Venus. He was quite interested, espe- refractor on a Berlebach Planet altazimuth mount and cially in the fact that a person on Venus would see an additional 70 mm small apo which is a finder Earth as a similarly bright star. This brings to mind the lines from Tennyson's “Locksley Hall: 60 Years scope. I have mirror diagonals fitted at all times. After”: Oct 6 “Hesper, Venus, were we native to that splendour or Struve 2335 is an optical triple star. The primary is in Mars, yellow. The magnitudes are: 9.3, 10.7 and 11.0. The We should see the globe we groan in, fairest of their separations (Sep) are 12 arc seconds (“) and 25.3”. evening stars' The position angles (PA’s) are 318˚ and 153˚. All 3 Could we dream of wars and carnage, craft and mad- stars were visible at 40x and 112x. The system is quite ness? near Vega. Roaring London, raving Paris, in that point of peace- Very close to the south of the stunning double star ful light? Zeta Lyrae is the faintest optical double star I have Might we not, in glancing heavenwards at a star so ever observed. Espin 2482’s magnitudes are 11.4 and silver fair, 12.2. Sep: 11.7”. PA: 162˚. To see both stars I Yearn and clasp the hands and murmur: “Would to needed my Nagler 5 mm which gives 225x. It was dif- God that we were there”?” ficult to see the B component with lower magnifica- Just as well that Tennyson didn't know what Venus tions. is really like! Here we have a lovely but quite faint double in Cygnus which I have not seen before. Struve 2747 is a Mars: (25-cm refl. X200): I had some reasonable true binary. Both G –class stars are yellow. Their mag- views of Mars after the global dust cloud cleared but nitudes are 8.5 and 8.7. Sep: 4.7”. PA: 267˚. 40x was the planet's low altitude prevented any really detailed sufficient to split it. But it was very attractive at study. The lingering effects of the dust cloud were 112x. still in evidence on August 30 but I was able to note

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It has been some years since I observed the famous TYC 2798-319-1 is an extremely faint orange car- binary 61 Cygni. Its two K –class stars are both yellow bon star a little bit east of 3.9 magnitude Mu Andro- –orange with magnitudes 5.2 and 6.1 and are very medae. This carbon has a magnitude of 12.1. To see easy to split even at 11x in my small 70 mm apo. But its orange hue I needed 167x. It is my 21st carbon star to admire the wonderful colours 40x and 112x do it in Andromeda. (My 67th overall). fine justice. Sep: 31.7”. PA: 152˚. One other thing I (Almach) is a hugely famous ought to mention is that 61 Cygni is the fourth closest binary. A is orange, B is blue. Sep: 9.4”. PA: 63˚. It binary to Earth after Alpha Centauri, Sirius and Epsi- looked very dramatic at 112x. Its distance is 393 light lon Eridani. 61 Cygni is only 11.4 light years from us. Imagine if there is an revolving around this years. system. There would be lots of hot summers because Nearby we have a very large open star cluster: the two stars would probably be visible all year NGC 752. Its optical diameter (45 arc minutes) is lar- round. However no exo-planet has been discovered as ger than any Full Moon. Its brightest stars are magni- yet. tude 8. There are about 70 stars waiting to be seen, and if there is no Moon about, it does look quite rich. 48 Cygni is another optical double. Its two stars It is irregularly shaped and scattered. At 40x with my have different colours: blue –white and yellow white. 2-inch 2˚ eyepiece I can fit all its stars in the same Magnitudes: 6.3 & 6.5. Sep: 182”. (Just over three arc field of view. minutes). PA: 177˚. At 11x I can see both stars of course. But its interesting colours are good at 40X. Oct 29 49 Cygni is a very nice double - although profes- Plenty of excitement was to be had with this next sional astronomers are not sure if it is a true binary. object. NC 4 is my 22nd carbon star in Magnitudes: 5.8 & 8.1. Sep: 2.7”. PA: 44˚. I required have observed and my 68th overall. It is a good strong 140x to see the split. It was very good at 167x and orange star with a magnitude of 9.6. However with 225x also. my Guide 9.1 DVD I can see that there is a red secon- dary star a mere 10” to the northeast from NC 4. Its Oct 16 designation is 3UC280-021968. The magnitude is a Over the last two years I have been seeking out faint 11.7. To observe both stars side by side I re- carbon stars in Andromeda. Lee 356 is my 19th and quired 225x and looked at this double for nearly one my 65th carbon star in total. The designation will be hour - I found it so captivating. My William Optics 4 most likely unknown to our readers. It was named af- mm eyepiece which gives 280x was also used. There ter Oliver J. Lee who was an American astronomer were plenty of double star enthusiasts expressing and he made lists of carbon stars in the 1940’s. My their interests on www.cloudynights.com. However it Guide 9.1 DVD gives it the long winded title 3UC267- must be noted that the two stars have differing dis- 260382. There is another designation however: C* tances. One experienced amateur on Cloudy Nights 3175. The star is very near which is 5.1 informed me that NC 4 is 7800 light years away from in magnitude. Lee 356 is quite faint: 9.6 magnitude, us. The secondary is nearer at 4800 light years away. but it does have a good orange hue. So it is an optical double.

Oct 18 Nov 1 Two nights later and I have found my 20th carbon My 23rd carbon star in Andromeda is TYC 3281- star in Andromeda - the 66th overall. TYC 3636 1782 2203. From 167x I could see its orange hue. The mag- is very dim. Its magnitude is 11.4 but at least it does nitude is very dim at 11.3. It is near 4.8 magnitude 60 have a good red colour. The lowest magnification with Andromedae. It’s my 69th carbon star overall. which to see its redness was 167x and I also used 225x I returned to the open star cluster M34 in Perseus on it. of magnitude 6 after one year. It is bright, very large On the same night I also observed another carbon and a little bit compressed at the centre even at star I had seen before. EU Andromedae which is a lit- 112x. There are two binaries within this magnificent tle bit brighter at 11.0 magnitude and has a good red system. HJ 1123 is very easy to split. Sep: 20”. PA: colour. 249˚. 40x splits it. But to split Stt 44 I used 112x. Sep: 1.4”. PA: 55˚. Oct 26 An easy true white binary is next. GRV 58 is a genuine binary in Andromeda. Its des- looks like two eyes looking back at us. With magni- ignation was named after John Greaves who is very tudes of 6.1 and 6.7 and a separation of 16.6” there is much alive today. Its magnitudes are 8.9 & 9.2. Sep: no need to go higher than 40x. The PA is 37˚. Dis- 32.9”. PA: 188˚. A is yellow. B is white. Split at 40X. tance: 455 light years. Nearby is Struve 72. It is an optical but splendid double star with magnitudes 8.4 and 9.3. What is Nov 10 most extraordinary is that both stars are red (M One of my favourite binaries of the entire year has class). Sep: 23.3”. PA: 173˚. Split at 40x. to be Achird (Eta Cassiopeiae). I observed it on the

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1st January 2018. And so here I am observing it again 167x and 225x. Its angular diameter was 3.7”. As a 11 months later. The G class primary is yellow, but result I am pleased to announce I have observed all the secondary is real fun and unusual. It is a class M seven planets in our solar system in 2018. A recent star which suggests it ought to be red. However, in discussion on the www.cloudynights.com web site truth to my eye, it is almond brown. Sissy Haas agrees suggested there is a third way of pronouncing the with this in her book Double Stars for Small Tele- name of the seventh planet from the Sun. Also I had scopes. Magnitude: 3.5 & 7.4. Sep: 13.3”. PA: 326˚. It the pleasure within the last two months from a Greek is only 19.4 light years away and I used my 112x eye- Cypriot friend who visited our home. Marios and some piece on it. Do see what you think of its colours and on Cloudy Nights state that the Greeks say OO-ran-us. report back here on the Observers’ Corner! The emphasis is on the first syllable –as in the word “boot”. I know there are some of us in the Irish Astro- S 404 is an optical double star in Andromeda. The nomical Society who greatly enjoy authentic pronun- magnitudes are 7.6 & 9.7. Sep: 29.2”. PA: 84˚. 40x is ciations. So by all means discuss this among your- enough to see both stars. James South discovered it. selves. It is all fun! He was a contemporary astronomer and friend of John Herschel. John’s father was William Herschel who dis- My final object is the 25th carbon star in Andro- covered Uranus. meda I have observed and my 71st overall. C* 95 has a good orange colour and shines at 10.4 magnitude. Its My 70th carbon star overall is my 24th in Andro- alternative designation is Case 713. I used magnifica- meda and it is by far the faintest I have found in this tions 112x, 167x and 225x. There is only one more wonderful constellation. C* 3227 is of 12.5 magnitude. carbon for me to find in Andromeda. I ought to see it 225x and 280x were used to see its red hue. My Guide before Christmas. Once I find it that will mean I will 9.1 DVD states its designation is 3UC262-17402. have observed all 26 carbon stars within this amazing constellation’s boundaries since 1st October 2016. Dec 3 Zeta Aquarii (Sadaltager) is getting wider year by From John O’Neill year but its PA is decreasing. This true binary has magnitudes 4.3 & 4.5. Sep is now 2.26”. PA is 156˚. All observations were made from Topsfield, MA, As a result it is easier to split it even at 112x. Both USA unless otherwise noted stars are yellow –white. The star can be found at the Sunspot Counts centre of the Y shaped asterism in northern Aquarius During the period September – November 2018, the from a dark site. It is nearly 92 light years away. maximum sunspot index I observed was on the 30th Not far away from Zeta Aquarii is a triple star September (W=13) and I observed no spots on the Sun Struve 2944. Stars A and B are a true binary; but C is on 22 days. Counts were conducted on 25 days during not. The magnitudes are: 7.3, 7.7 and 8.6. Sep: 1.8” this period. All were reported to the AAVSO Solar Sec- and 62.2”. PA’s: 306˚ & 86˚. All 3 stars were ob- tion. I used a 70 mm refractor, equipped with a Thou- served at 112x. sand Oaks Type 2+ solar filter. STFA 59 is an optical binary in Aquarius. Magni- tudes: 5.5 & 7.2. Sep: 257”. PA: 149˚. It’s easy to Sigma Orionis split at 11x. But at 112x I noticed the primary is or- 2018 September 29-30 at 08.30 UT ange and the secondary is blue. The companions C, D and E were easy in this multi- Struve 2980 is a true binary in Aquarius with yellow ple star system. AB appeared as a single object. Also –orange and blue colours. Magnitudes: 8.1 & 10.5. known as Struve 762. Sep: 4.6”. PA: 107˚. 112x is sufficient to split this Struve 761 near-by is also a multiple star, with its one. four components (which form two pairs) easily re- Struve 2993 is very nice wide optical triple also in solved. 28 cm SCT at 200x. Seeing: moderate. Aquarius. Magnitudes: 7.6, 8.2 and 9.1. Sep: 24.8” & 79.7”. PA’s: 176˚ & 131˚. The colours are yellow – Galaxies NGC 3077 and NGC 2976 in Ursa Major white, yellow and blue. All 3 stars are visible at 40x. 2018 November 8-9 at 09.15 UT. The above doubles and triples are all quite near NGC 3077 appears oval in PA 60 deg, with a much the large gas giant planet Neptune –the eighth planet brighter interior. Appears as nearly 2' long in the ma- in our solar system. Its distance from us was about jor axis. 4,471,000,000 km. I noticed its blue hue at 167x and NGC 2976 appears faint, but definite. Appears 225x. It will be in Aquarius for some years to come elongated in PA 150 deg and I estimated the length as and is currently at magnitude 7.9. Its angular diame- 4'. Almost uniform in brightness, apart from fading ter was a small 2.3”. edges. Faint star on SW edge. Uranus was right on the border of southern Aries 28 cm SCT at 117x. Transparency: goodish. Alti- and eastern Pisces this same night. Shining at magni- tude about 59 deg. Both galaxies belong to the M81 tude 5.7, and about 2,961,000,000 km from Earth, I group of galaxies. noticed it has a mostly green hue with a bit of blue at

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Comet 38P Stephan-Oterma with no trouble and checked their identity by compar- 2018 October 18-19 at 07.55 UT ing data, especially the Position Angle, with the cata- logues. These doubles included Iota and Struve 239 in Appears faint, but definite. Diameter in range 1.0' Triangulum, Gamma and Epsilon Arietis and then using to 1.5', but edges fade into the sky background. Too a 16mm Plossl had a nice view of 52 Orionis. M42 as faint to do a magnitude estimate. DC=1. ever was a rewarding spectacle, the Trapezium show- ing three stars immediately but the fourth elusive at 28 cm SCT at 117x. Altitude 56 deg. Lies in Gemini, first. 12.3' WNW of PPM 122881. Clear sky, good transpar- ency. On the following night I succeeded with Alpha and Fl 65 Psc, easily found in what to the naked eye on 3 Juno: 2018 November 6-7 at 07.58 UT most nights is a barren region of sky. An easy object. Appears just brighter than HIP I really enjoyed getting back to observing again 18583 (mag 7.6). Lies 0.5 deg SSW of 35 Eridani. I and such is the accuracy of the Kajers drive I might confirmed movement (south-west) on the next eve- even succeed with a bit of imaging without auto guid- ning. 12x36 binoculars. Altitude 36 degrees. ing but relying on stacking images. Having said all that I am always amazed at the Moons of Uranus: 2018 November 15-16 at 03.40 UT amount of observing Aubrey gets through with an Alt- The planet itself appeared as a featureless disk. azimuth mount. I might have given him a run for his Oberon and Titania were readily visible. They were money when I was in my twenties and we honed our predicted to be 28" and 26" respectively from the skills on quite small telescopes and very basic star planet. The 61 cm is the famous 24 inch Clark Tele- charts. But the skies were dark. Even in Sandymount scope of 1896. 362x. Seeing: ok. Clear sky. Altitude 54 one might see all the stars of Pisces even to fifth mag- deg. Site: Lowell Observatory, Flagstaff, Arizona, USA nitude.

M15: 2018 November 18-19 at 02.20 UT This globular shows a small condensed Deirdre Kelleghan sent in the astounding sketch below of Comet 46P/ core. Stars resolved right into the centre. 61 Wirtanen which graced our skies at the end of 2018. Instrument used was a 200mm Dobsonian (1,200 mm FL / 32 mm eyepiece/ 37X/ pas- cm refractor, 233x. Seeing: goodish. Clear tel and gel pen). The comet was estimated as 4.5 mag. DC 4 coma sky. Altitude 62 deg. Site: Lowell Observa- visible naked eye also, huge diffuse object. Deirdre adds, “ I thought I tory, Flagstaff, Arizona, USA observed some radial features but not clear enough to include in the sketches. The edges/shape of the coma was difficult to see clearly. From Liam Smyth No green observed. I feel lucky to have seen it.” Louisburgh Co Mayo. No longer having the convenience of a permanent observation dome in my back gar- den along with its Goto drive on a G11 Mount, it has taken me some time to organise things astronomical to my liking. I am using an old orange tube C8 on its original non-adjustable tripod. Away back in the 1980’s I did upgrade the Celestron paired synchronous motors to a new worm and quartz drive by a firm, (actually as far as I remember a one man op- eration by a Ray Thomas) trading under the names Kencor and Kajers. Instead of the Los- mandy Gemini Goto system I blew the dust off my Sky Commander digital circles and was able to connect it to the C8 using a venerable kit I purchased from Lumicon many years ago. So, on the night of October 17th I put the outfit to the test. I must say I was very happy with the re- sults. Having used an initial two star align- ment I aimed for M15 in Pegasus and sure enough there it was, comfortably into the 45 arc-minutes field of a 40mm Plossl. In this urban environment the globular was visible but hardly spectacular. Then going for M33 I was sure I was pointing at the right place but there was no sign of the galaxy. So I decided to seek out a few doubles. I found them all

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