The Prairie Astronomer March 2016 Volume 57, Issue #3

March Program: Mark Ellis: “Space Law”

Brett Boller’s Milky Way See page 4

MSRAL

The Newsletter of the Prairie Astronomy Club The Prairie Astronomer

NEXT PAC MEETING: March 29, 7:30pm at Hyde Observatory CONTENTS PROGRAM 4 Meeting Minutes March: Space Law Part I - Mark Ellis 5 2017 Eclipse Planning The Martian portrayed a positive future for the US Space Program. Meeting NASA, with help from China, was able to rescue Mark Watney after being marooned on Mars. 6 Astrophotography 7 Black Hole Rotation To do this, we saw them use great technology that exists today. Rate But what are the legal implications of interplanetary travel? Attorney Mark Ells, a recent graduate of UNL's Space Law 9 Mercury’s Crust Program, will explore that topic at the March PAC meeting. 11 Observatory Update: IC 239 13 DSLR Astrophotography FUTURE PROGRAMS 17 From the Archives April: Space Law Part II - Elsbeth Magilton & Prof Frans Von der Dunk 18 April Observing June: Solar Party 19 Focus on August: NSP Review 20 Gravitational Wave Astronomy 22 Ceres Bright Spots (Again) 24 Club Information Buy the book! The Prairie Astronomy Club: Fifty of Amateur Astronomy. Order online from Amazon or lulu.com. EVENTS

PAC Meeting

PAC Meeting Tuesday March 29th, 2016, 7:30pm Hyde Observatory PAC E-MAIL: Astronomy Day, Sunday, April 17 at Morrill Hall [email protected]

PAC Meeting Tuesday April 26th, 2016, 7:30pm Hyde Observatory PAC-LIST: Subscribe through GoogleGroups. PAC Meeting To post messages to the list, send Tuesday May 31st, 2016, 7:30pm to the address: Hyde Observatory [email protected]

Newsletter submission deadline April 16 2016 STAR PARTY DATES ADDRESS The Prairie Astronomer c/o The Prairie Astronomy Club, Inc. P.O. Box 5585 Lincoln, NE 68505-0585

Photo by Brian Sivill WEBSITES Star Party Star Party Lunar Party www.prairieastronomyclub.org Date Date Date https://nightsky.jpl.nasa.gov www.hydeobservatory.info January Jan 1st Jan 8th www.nebraskastarparty.org February Jan 29th Feb 5th www.OmahaAstro.com March Mar 4th Mar 11th Panhandleastronomyclub.com April Apr 1st Apr 8th Apr 15th www.universetoday.com/ May Apr 29th May 6th May 13th www.planetary.org/home/ http://www.darksky.org/ June May 27th Jun 3rd July Jul 1st Jul 8th July 31st NSP - Aug 5th August Jul 29th Aug 5th Aug 12th August Aug 26th Sep 2nd Sep 9th September Sep 23rd Sep 30th October Oct 21st Oct 28th November Nov 25th Dec 2nd December Dec 23rd Dec 30th The Prairie Astronomer 3 PAC Meeting Minutes

Prairie Astronomy Club by John, Mike Kearns, Rick Jim presented his observing Brown and Lee Taylor. John Minutes for the meeting of report for March. The club star summarized the audit for the February 23, 2016 parties are March 4th and 11th club. John is working on an at the Farm. easier way for the President Jim Kvasnicka called membership to access the the meeting to order. 11 Club Business: roster. members, 2 guests. Astronomy Day is coming up Adjourn to the program on the Jim welcomed members and on April 17 from 1:30-4:30. We Astronomical League's guests to the meeting. need telescopes for display in observing programs. Morrill Hall. If anyone would like Jim Reviewed upcoming events to provide a telescope, please Respectfully submitted by and star parties for the month. contact Zach by March 1. Lee Taylor We reviewed the benefits and John Reinert provided the requirements of club treasurer's report. The audit membership. was completed on February 6th

The new mural has been installed at Hyde Observatory. This photo is a composite of the Milky Way taken by Brett Boller and Dave Knisely at the Nebraska Star Party in July, 2015.

The Prairie Astronomer 4 2017 Solar Eclipse Planning Committee Meeting Minutes

March 3, 2016 o Sibbersnsen mentioned that these 5:30 pm, Hyde Memorial Observatory trainings could also be done by the NASA Ambassadors to reach more Present: Lee Thomas, Dan Delzell, Jamie Kelley, individuals Dave Churilla, Guest - Michael Sibbernsen - The need for a brochure with eclipse and The group invited Michael Sibbernsen to share safe viewing info was discussed. info about other solar eclipse events going on throughout Nebraska on August 21, 2017. o Sibbersnsen thinks this is a good - The Nebraska Eclipse Consortium this idea group is made up of individuals/agency’s o It would be ideal for the Consortium involved in planning solar eclipse events to work together on this so that in- throughout the state. formation being distributed is con- o Lee Thomas will be notified via Sib- sistent bernsen of the next meeting o Brochure should be ready by Janu- o There will be a website, it is not ac- ary 1, 2017 tive right now. - Other media coverage will be needed ▪ Listing of activity locations o Where and how to view ▪ Public can go to for informa- o Resources available tion o Contacts – Hyde/Web o NASA NE Space Grant - Promotion of the eclipse can begin ▪ Statewide ambassadors o 5 min presentation as part of Satur- o Distribution of up to 50,000 solar day night program. eclipse glasses - Hyde will be open for the eclipse - In addition to the Eclipse Consortium, Sib- bernsen will be involved, on the day of the o There will need to be a capacity set eclipse, with the release of a of weather balloons documenting the o Traffic control will be needed eclipse. o At least 10 volunteers will be need- ed Updates on activities from Hyde/PAC: o Exclusive use permits with Parks - Hyde has ordered 2000 solar glasses. and Rec will need to be completed 1000 were ordered in 2014.

- The committee has discussed possibly - Other happenings in 2017 train the trainer workshops for LPS sci- ence teachers and others leading up to o Hyde’s 40th Anniversary the eclipse. th o The training could be done also via o Nebraska’s 150 video conference or pre-recorded - A chair for the committee is needed training

The Prairie Astronomer 5 Astrophotography by Club Members

Beth Jenckes Clocking the Rotation Rate of a Supermassive Black Hole

A recent observational campaign black hole is one third of the emit huge amounts of electro- involving more than two dozen maximum spin rate allowed in magnetic radiation due to the optical telescopes and NASA's General Relativity. This 18 billion infall of matter into their space based SWIFT X-ray heavy black hole massive black holes. telescope allowed a team of powers a quasar called OJ287 astronomers to measure very which lies about 3.5 billion light This quasar lies very close to accurately the rotational rate of years away from Earth. Quasi- the apparent path of the Sun's one of the most massive black stellar radio sources or `quasars' motion on the celestial sphere holes in the universe. The for short, are the very bright as seen from Earth, where rotational rate of this massive centers of distant galaxies which most searches for asteroids and comets are conducted.

An illustration of the binary black hole system in OJ287. The predictions of the model are verified by observations. The Prairie Astronomer 7 Therefore, its optical photometric precessional rate depends The observations leading to measurements already cover mainly on the two black hole accurate spin measurement more than 100 years. A careful masses and the rotation rate of have been made due to the analysis of these observations the more massive black hole. In collaboration of a number of show that OJ 287 has produced 2010, Valtonen and optical telescopes in Japan, quasi-periodic optical outbursts collaborators used eight well South Korea, India, Turkey, at intervals of approximately 12 timed bright outbursts of OJ287 Greece, Finland, Poland, years dating back to around to accurately measure the Germany, UK, Spain, USA 1891. Additionally, a close precession rate of the smaller and Mexico. The effort, led by inspection of newer data sets hole's orbit. This analysis Staszek Zola of Poland, reveals the presence of double- revealed for the first time the involved close to 100 peaks in these outbursts. rotation rate of the massive astronomers from these black hole along with accurate countries. Interestingly, a These deductions prompted estimates for the masses of the number of key participants Prof. Mauri Valtonen of two black holes. This was were amateur astronomers University of Turku, Finland and possible since the smaller black who operate their own his collaborators to develop a hole's orbit precess at an telescopes. Valtonen's team model that requires the quasar incredible 39 degrees per that developed and OJ287 to harbour two unequal individual orbit. The General contributed to the spinning mass black holes. Their model Relativistic model for OJ287 also binary black hole model involves a massive black hole predicted that the next outburst include theoretical with an accretion disk (a disk of could occur around the time of astrophysicist A. Gopakumar interstellar material formed by GR Centenary, 25 November from TIFR, India, and Italian matter falling into objects like 2015, which marks the 100th X-Ray astronomer Stefano black holes) while the anniversary of Einstein's Ciprini who obtained and comparatively smaller black hole General Theory of Relativity. analyzed the X-ray data. revolves around it. The quasar OJ287 is visible due to the slow An observational campaign was The occurrence of the accretion of matter, present in therefore launched to catch this predicted optical outburst of the accretion disk, onto the predicted outburst. The OJ287 also allowed the team largest black hole. Additionally, predicted optical flare began to confirm the loss of orbital the small black hole passes around November 18, 2015 and energy to gravitational waves through the accretion disk during reached its maximum brightness within two percent of General its orbit which causes the disk on December 4, 2015. It is the Relativity's prediction. This material to heat up to very high timing of this bright outburst that provides the first indirect temperatures. This heated allowed Valtonen and his co- evidence for the existence of material flows out from both workers to directly measure the a massive spinning black hole sides of the accretion disk and rotation rate of the more binary emitting gravitational radiates strongly for weeks. This massive black hole to be one waves. This is encouraging causes peaks in the brightness, third of the maximum spin rate news for the Pulsar Timing and the double peaks arise due allowed in General Relativity. In Array efforts that will directly to the ellipticity of the orbit, as other words, its Kerr parameter detect gravitational waves shown in the figure. is accurately measured to be from such systems in the near 0.31 and its maximum allowed future. Therefore, the present The binary black hole model for value in General Relativity is optical outburst of OJ287 OJ287 implies that the smaller one. In comparison, the Kerr makes a fitting contribution to black hole's orbit should rotate, parameter of the final black hole the centenary celebrations of and this changes where and associated with the first ever General Relativity and adds to when the smaller hole impacts direct detection of gravitational the excitement of the first the accretion disk. This effect waves is only estimated to be direct observation of a arises from Einstein's General below 0.7. transient gravitational wave Theory of Relativity and its signal by LIGO.

The Prairie Astronomer 8 Expanded-color image of Mercury's 52-km Degas crater, showing an abundance of low-reflectance material (LRM). Dark Stains on Mercury Reveal Its Ancient Crust

Jason Major, Universe Today Ever since the MESSENGER Commonly found within and much of the planet was still spacecraft entered orbit around around impact craters and molten. Mercury in 2011, and indeed volcanic vents, the dark spots on “Experiments and modeling even since Mariner 10‘s flyby in Mercury—also referred to as show that as this magma 1974, peculiar “dark spots” “low-reflectance material,” or ocean cooled and minerals observed on the planet’s surface LRM—were originally suspected began to crystallize, minerals have intrigued scientists as to to contain carbon delivered to that solidified would all sink their composition and origin. the planet by comets. with the exception of graphite, Now, thanks to high-resolution Data from MESSENGER’s which would have been spectral data acquired by Gamma-Ray and Neutron buoyant and would have MESSENGER during the last Spectrometer (GRNS) and X-ray accumulated as the original few months of its mission, instruments confirmed the LRM crust of Mercury,” said Rachel researchers have confirmed that to contain high amounts of Klima, co-author of a recent Mercury’s dark spots contain a graphitic carbon, but likely study on LRM and a planetary form of carbon called graphite, originating from within Mercury geologist at the Johns Hopkins excavated from the planet’s itself. It’s thought that Mercury University Applied Physics original, ancient crust. was once covered by a crust Laboratory. “We think that LRM composed of graphite, when may contain remnants of this

The Prairie Astronomer 9 primordial crust. If so, we may be On Earth graphite is used in planet closest to the Sun. The observing the remains of industry to make bricks that line MESSENGER spacecraft Mercury’s original, 4.6-billion- refractory furnaces and increase launched on August 3, 2004, -old surface.” the carbon content of steel. It’s and entered orbit about also widely used in fire Mercury on March 17, 2011 Although similar in visible retardants, batteries, and (March 18, 2011 UTC). On coloration and covered in lubricants, and is mixed with clay April 30, 2015, after four years craters, cracks, and mountains, in various amounts to create the in orbit MESSENGER‘s any similarities between Mercury “lead” in pencils (which, by the mission and operational life and other smaller worlds in our way, contain no actual lead.) came to an end when it Solar System—including our impacted the surface of Moon—end there. Mercury has a These findings have been Mercury in its northern polar formation history all it own and is published in the March 7, 2016 region. compositionally unique among Advanced Online Publication of the planets. Nature Geoscience. These data revealing such a MESSENGER (MErcury Surface, Source: Carnegie Science and relatively high concentration of Space ENvironment, JHUAPL graphite in Mercury’s crust only GEochemistry, and Ranging) adds to those differences, and was a NASA-sponsored scientific also tell us about the various investigation of the planet elements that were present Mercury and the first space around the Sun when the planets mission designed to orbit the were forming. “The finding of abundant carbon on the surface suggests that we may be seeing remnants of Mercury’s original ancient crust mixed into the volcanic rocks and impact ejecta that form the surface we see today,” said Larry Nittler, research paper co-author and Deputy Principal Investigator of the MESSENGER mission. “This result is a testament to the phenomenal success of the MESSENGER mission and adds to a long list of ways the innermost planet differs from its planetary neighbors and provides additional clues to the origin and early evolution of the inner Solar System.”

Low-reflectance material surrounding an 80-km crater called Basho, imaged in May 2012

The Prairie Astronomer 10 Observatory Update: IC 239 Rick Johnson

IC 239 is a low surface Arp 135 seem to collect around Attempts to brightness spiral that is 32 to 34 million light-years get a Tully- considered part of the NGC values down to the 20 million Fisher 1023 group. NGC 1023 is Arp light-years I used and up to 64 distance 135 and is located about 45 million light-years are found in estimate are minutes of arc east of IC 239. It the reasonably current bugged by not is located in far eastern literature. I'll go with 32 million being able to Andromeda while NGC 1023 is light-years simply because that determine in Perseus. The distance to is also the redshift value for IC exactly how both is highly controversial. As 239. Using that distance the face on we are seeing it. Two a member of the 1023 group it separation of IC 239 from Arp different methods of determining should be at approximately the 135 is only 430,000 light-years this give two very different same distance. When I took Arp so it is possible that IC 239 is answers. With so many 135 back in October of 2008 I feeling the tidal forces of the far uncertainties it is possible, but put it at 20 million light-years. more massive Arp 135. Indeed unlikely the two aren't related. That isn't likely correct. While it shows faint extended arms or My post about NGC 1023/Arp current distance estimates for plumes to the north and south. 135 with its likely too close

The Prairie Astronomer 11 distance estimate can be seen shaken up the core black hole to Ignoring them it is 30,000 light- here. a rather active state. That may years in size. So not only is it a be Arp 135. Assume the 32 small spiral it's low surface NED classifies IC 239 as million light-year distance I get a brightness indicates few SAB(rs)cd LINER2. This size of about 42,000 light-years filling what little volume it takes indicates something may have and that includes the plumes. up. As such it shouldn't be hard

The Prairie Astronomer 12 for a larger companion to distort constellation borders were not dwarf member of the group. In it as appears to have well defined and it may well fact it's other catalog name is happened. Though if it has a have been in that constellation NGC 1023 GROUP:[TT2009] ton of dark matter we can't see by the boundaries is use at the 18. That, I've found, doesn't all this is moot. time. Today it is only in count for much as galaxies Andromeda by 28 arc minutes. labeled as members of other It was discovered groups often have redshifts that photographically by Isaac There is only one other obvious put them billions of light-years Roberts in 1893 using the 20" galaxy in my image, PGC from the cluster whose name reflector at his observatory 2802360 to the east. Another they carry. With nothing worth "Starfield", Crowborough Hill, very low surface brightness annotating but for IC 239 I didn't Sussex, UK. He put it in galaxy. No distance information prepare an annotated image. Perseus though at that time the is available at NED. It may be a

DSLR Astrophotography Untracked Karoline Mrazek and Erwin Matys, Project Nightflight

With DSLRs and standard similar exposures at very high sample images show, the camera lenses astrophotography ISO ratings and keep the single results are quite astounding. is on the verge of a new , exposures so short that no For example, with a 135mm where tracking is no longer tracking is needed. The lens we captured detailed absolutely mandatory. When we individual frames can then be images of star clusters and heard about the technique digitally combined in a stacking nebulae, reaching a limiting described in this article, we program to create a final picture magnitude of 14mag. Images immediately wanted to give it a that shows faint details and is shot with a 50mm lens easily try. It allows any stargazer using free of the noise that comes with captured star clouds and a modern DSLR to capture the high ISO setting. As the colorful, noise-free images of deep-sky objects, without an equatorial mount or tracking device needed. How it Works The technique described here was originally brought to our attention by our fellow observer Wolfgang Vollmann, who has been using it for some time to capture comets. His initial results were promising and we decided to give it a closer look and develop it further where possible. After a series of experiments we are now able to present a tried and tested workflow that guarantees great images of star fields. The basic The Great Sagittarius Star Cloud, imaged with a 50mm lens idea of the method is actually without tracking. All images were captured under the pristine quite simple: Shoot a lot of skies of La Palma island. See text for exposure details. The Prairie Astronomer 13 setting up your equipment, set the DSLR's picture mode to RAW, white balance to daylight and sensitivity to ISO 6400 or higher. Turn off any presets for noise reduction, sharpening or color enhancement. Switch your lens to manual focus and use magnified live mode to focus your lens on a brighter star. Finally, step down your lens at least one f-stop from wide open. This will reduce lens aberrations noticeably, especially when using a zoom lens. The next step is to program your remote release timer for a greater number of exposures, 100 is a good value to start with. When you Typical setup for untracked astrophotography; instrument set the exposure time for the requirements are minimal. All you need is a DSLR, a tripod and a individual frames, be aware remote release timer. You may want to add a lens hood and a that it is limited by the focal right-angle viewfinder. length of your lens. With a 50mm lens, 3-second nebulae in the Milky Way with newer DSLR models can be exposures are fine, with a great detail. remote controlled via a 135mm lens exposure time smartphone app. Additionally, should be around 1 second. What You Need you might want to use a right- To determine the maximum angle viewfinder and a lens exposure time for your The imaging method is very hood. As the shopping list specific DSLR and lens more simple and therefore instrument shows, any astrophotographer precisely, use the formula requirements are minimal. First or nature-interested terrestrial given in the workflow tutorial of all, you will need one of the photographer will probably that is available for free later DSLR models that allow already own most of these download (see link at the end ISO settings of 6400 or higher. items. For this reason the of the article). If you keep As a lens, any wide angle, method is ideal for casual your exposure times within standard or tele lens will do, astrophotography to capture a the specified limits, the stars even the typical kit zoom lenses comet, a nova or simply to take on your pictures will be nice will work. A small but sturdy some pictures of your favorite and round without any signs tripod is required for mounting deep-sky objects during a of trailing. As soon as you and pointing the camera. For vacation at a dark site. have completed these steps, field work at remote sites we your camera is ready and it is recommend the new, lightweight How to Shoot time to frame your target. models (<0.5kg) with a ball head Point your DSLR at the star that are available from several First of all, shoot at the darkest field, nebula or comet you manufacturers. The last location and under the best want to image. Place the mandatory item is a remote skies you have access to. This object slightly off center in the release timer that allows you to will guarantee that the individual camera's viewfinder, so it will program a series of exposures. exposures already show the drift over the center during As an alternative, many of the best contrast possible. After your exposure series. Start The Prairie Astronomer 14 your timer and let your camera record the target. Once the exposure series is finished, cover your lens and shoot at least 10 dark frames with the same exposure settings. To give you an idea which settings work well, the images accompanying this article were shot at rural sites on La Palma Island with a Canon 1100D body set at ISO 6400 with series of 100 exposures each. We used a 50mm lens @f/2.8 and a 135mm lens @f/4 with 3 and 1 second exposures, respectively. Except that our Canon 1100D is modified for optimum H-alpha sensitivity, it is an ordinary, off- Omega Centauri Cluster, imaged with a 135mm lens without the-shelf APS-C sized camera tracking. Limiting magnitude is 14mag, see text for exposure body. Although an unmodified details. DSLR will record less red nebulosity it will still work very well for the method described. register and digitally combine image processing software the individual frames. The result such as Photoshop. Processing the Images is a calibrated stack of your images that is practically noise- Some Final Thoughts Once you return from your free. To get the maximum out of imaging trip, star party, vacation As our experiments show, your resulting image you will or camping hike, it is time to tracking is no longer an then have to enhance it using an develop the final images. As we absolute requirement for mentioned above, the magic stunning star field images. But unfolds with the stacking of the individual exposures. This procedure cancels out the noise of the high ISO setting and enhances faint details as well as small stars. For the task of stacking the images there are many different programs available. We recommend the widely used freeware Deep Sky Stacker to start with, but any other stacking software will do the job as well (For tips on the parameter settings in Deep Sky Stacker follow the link to the tutorial at the end of the text). With the stacking software of your choice, simply import your exposure series as well as the Deneb and the North America Nebula, imaged with a 50mm lens dark frames and let the program without tracking. See text for exposure details.

The Prairie Astronomer 15 don't get us wrong: A stack of - The technique is so simple - The method is ideal in all short untracked shots is no that even beginners to situations when the substitute for a stack of tracked astrophotography will easily photographer doesn't want to long exposures, which will have master it. Therefore, it is no hassle with the complexity a better signal-to-noise ratio in longer mandatory to buy an that comes with the use of an any case. Nevertheless, we find equatorial mount or sky tracker equatorial mount or tracking it very interesting how far a to get started with device. modern DSLR can go without astrophotography. any tracking. And with DSLR The authors Karoline Mrazek cameras getting more and more - Instrument requirements of and Erwin Matys are founding sensitive, this is only the untracked DSLR members of the beginning. As far as we can tell, astrophotography are minimal. astrophotography group even today there are a lot of Photographers who want to project nightflight. Check out possible applications for this travel light to dark locations will their images, tests and tools method of untracked DSLR have less weight to carry with at www.project-nightflight.net astrophotography. To name only them. a few:

Download the Tutorial A compact tutorial of the workflow described can be downloaded from the tests & tools section on our website. We prepared the tutorial for all fellow photographers, because this method provides an easy way to capture star fields, nebulae, star clusters, Milky Way regions and even binocular comets with minimal equipment. The full article, including the workflow tutorial can be downloaded here.

Orion Nebula M42, imaged with a 135mm lens. The colorful and noise-free picture is the result of a stack of 100 single exposures.

Scutum Star Cloud, imaged with a 50mm lens without tracking. Short focus lenses work especially well for capturing Milky Way vistas like this one. See text for exposure details.

The Prairie Astronomer 16 From the Archives: March, 1976

Comet West – Brilliant, Brian G. Marsden of the daylight. The comet declined to Unexpected Maverick – Now Smithsonian Astrophysical magnitude 0 by March 3, is it Comets West? Observatory speculated during approximately magnitude 1 on the week of March 15 that March 6, and was still at Aside from its unanticipated Comet West might have broken magnitude 1.8 late on March 5. brilliance (consistently one to up into a main cometary Original predictions were that two magnitudes brighter than nucleus and as many as three West should have been down initial predictions), Comet West smaller nuclei. Visual to magnitude 3.2 on the 8th--so, has managed to command the observations beginning March 5 given its rapid advance into attention of professionals and indicated secondary nuclei at dark skies, providing contrast, amateurs with some interesting p.a. 50 degrees, separation 3", and its retained brilliance, antics in the morning sky. magnitude difference 0.5; Comet West was turning out to another at 120 degrees, be everything Kohoutek wasn't. Its prominent tail has, on close magnitude 0, no separation observation, been seen to data; and one at 350 degrees, include a broad dust tail separated by about 4", composed of a number of magnitude difference 0.5. “synchronic bands‘, according Reliable estimates on Comet to Z. Sekanina of the Center for West indicated a magnitude of astrophysics. “The bands -3.65 shortly after perihelion on showed a systematic February 26, viewed during translational motion of about 1.60 per day and rotated at about 13° per day relative to the faint plasma tail, one of them essentially coinciding with its southern border." On a print obtained March 5, Sekanina noted as many as 20 "synchronic bands‘, the most distant of which reached as far as 19 degrees from the nucleus,with "the dust tail extending to some 25 degrees. Sekanina explained that the dust tail was composed of postperihelion particle emissions, while a faint section northeast of the nucleus was made up of somewhat heavier particles emitted during the week before perihelion.

Comet West was discovered in photographs by Richard West on August 10, 1975. It reached peak brightness in March 1976. During its peak brightness, observers reported that it was bright enough to study during full daylight. Despite its spectacular appearance, it did't cause much expectation among the popular media. The comet has an estimated orbital period of 558,000 years. Photo credit: J. Linder/ESO. [Source: Wikipedia] The Prairie Astronomer 17 April Observing: What to View Jim Kvasnicka

This is a partial list of objects visible for the upcoming month. NGC and other Deep Sky Objects Planets NGC 2841: Galaxy in Ursa Mercury: Low in the WNW shining as bright as Major. -1.5 in early April. NGC 2903: Galaxy in . Jupiter: Shines at magnitude -2.3 with a disk 41” NGC 3184: Galaxy in Ursa wide. Major. Mars and Saturn: The two form a pair just NGC 3242: The Ghost of above Antares. Mars rises around midnight with Jupiter in Hydra. Saturn 40 minutes later. Mars increases in NGC 3384/NGC 3389: magnitude from -0.6 to -1.4. This is the largest Galaxies in the same FOV with M105 in Leo. Mars will appear in the last 10 years with a disk NGC 3521: Galaxy in Leo. 16” wide. Venus: Rises just a half hour before the Sun and Double Star Program List after April 9th is not visible. Alpha Leonis: , white primary with a Uranus and Neptune: Both are not visible in pale yellow secondary. April. : Algieba, pair of yellow stars. 54 Leonis: Yellow primary with a greenish Meteor Showers colored secondary. Lyrids: Peaks at 2:00 am the morning of April Alpha Canum Venaticorum: Cor Caroli, blue- 22nd. This weak shower will be impacted by the white and greenish yellow pair. full Moon. Zeta Ursa Majoris: Mizar, white pair. Gamma Virginis: Porrima, close pair of yellow Messier List stars. M40: Multiple star in Ursa Major. 24 Comae Berenices: Yellow primary with a M65/M66: Galaxies in the Leo Triplet Group. pale blue secondary. M95/M96: Galaxies in Leo that fit in the same Delta Corvi: White and rose colored pair. FOV. M105: Galaxy in Leo. Challenge Object M106: Galaxy in Canes Venatici NGC 3995 Group: The brightest member in a M108: Galaxy in Ursa Major. trio of galaxies in Ursa Major. Other galaxies M109: Galaxy in Ursa Major. include NGC 3991 and NGC 3994. Last Month: M41, M44. M46, M47, M48, M50, M67, M81, M82, M93 Next Month: M49, M51, M61, M63, M64, M85, M94, M101, M102, M104

The Prairie Astronomer 18 Focus on Constellations: Leo Jim Kvasnicka

Leo Mythology

Leo, the Lion is one of the most distinctive In Greek mythology the celestial Lion was constellation patterns in the sky. The head and associated with the Nemean Lion slain by forequarters of the Lion are marked by the Hercules as the first of his Twelve Labors. The asterism called the sickle. Leo, as is typical of Greeks inherited the Lion from the Babylonians constellations off the Milky Way, contains many before them. A common theme in Babylonian art galaxies. A number of them are large and bright. is a battle between a Lion and a Bull with the Lion Leo contains five galaxies with Messier numbers: always defeating the Bull. M65, M66, M95, M96, and M105. The constellation contains several interesting double Number of Objects Magnitude 12.0 and stars. One of them Algieba, Gamma Leonis, is Brighter one of the finest double stars in the sky. Leo contains the radiant of the Leonid meteor shower Galaxies: 58 which peaks every year around November 17th. The constellation Leo is best seen in April.

Showpiece Objects

Galaxies: M65, M66, M95, M96, M105, NGC 2903, NGC 3521, NGC 3628 Multiple Stars: Alpha Leonis (Regulus), Gamma Leonis (Algieba), 54 Leonis, 88 Leonis

Photo: Till Credner - Own work: AlltheSky.com

The Prairie Astronomer 19 Gravitational Wave Astronomy Will Be The Next Great Scientific Frontier

This article is provided by NASA Space Place. Ethan Siegel With articles, activities, crafts, games, and lesson plans, NASA Space Place encourages everyone to get excited about science and technology. Visit spaceplace.nasa.gov to explore space and Earth science!

Imagine a world very different subtlety here is that binary patterns. From that tiny amount from our own: permanently pulsars may contain a single of data, scientists were able to shrouded in clouds, where the neutron star, so it’s best to be conclude that two black holes, sky was never seen. Never had specific], where two neutron of 36 and 29 solar masses anyone see the Sun, the Moon, stars orbit one another at very apiece, merged together, the stars or planets, until one short distances, had previously emitting 5% of their total mass night, a single bright object shown this phenomenon of into gravitational wave energy, shone through. Imagine that orbital decay, but gravitational via Einstein's E = mc2. you saw not only a bright point waves had never been directly of light against a dark backdrop detected until now. During that event, more energy of sky, but that you could see a was emitted in gravitational banded structure, a ringed When a gravitational wave waves than by all the stars in system around it and perhaps passes through an objects, it the observable Universe even a bright satellite: a moon. simultaneously stretches and combined. The entire Earth was That's the magnitude of what compresses space along compressed by less than the LIGO (the Laser Interferometer mutually perpendicular width of a proton during this Gravitational-wave directions: first horizontally, event, yet thanks to LIGO's Observatory) saw, when it then vertically, in an oscillating incredible precision, we were directly detected gravitational fashion. The LIGO detectors able to detect it. At least a waves for the first time. work by splitting a laser beam handful of these events are into perpendicular “arms,” expected every year. In the An unavoidable prediction of letting the beams reflect back future, different observatories, Einstein's General Relativity, and forth in each arm hundreds such as NANOGrav (which gravitational waves emerge of times (for an effective path uses radiotelescopes to the whenever a mass gets lengths of hundreds of km), and delay caused by gravitational accelerated. For most systems then recombining them at a waves on pulsar radiation) and -- like Earth orbiting the Sun -- photodetector. The interference the space mission LISA will the waves are so weak that it pattern seen there will shift, detect gravitational waves from would take many times the age predictably, if gravitational supermassive black holes and of the Universe to notice. But waves pass through and many other sources. We've just when very massive objects orbit change the effective path seen our first event using a new at very short distances, the lengths of the arms. Over a type of astronomy, and can now orbits decay noticeably and span of 20 milliseconds on test black holes and gravity like rapidly, producing potentially September 14, 2015, both never before. observable gravitational waves. LIGO detectors (in Louisiana Systems such as the binary and Washington) saw identical pulsar PSR B1913+16 [the stretching-and-compressing

The Prairie Astronomer 20 Gravitational Wave Astronomy, continued.

Image credit: Observation of Gravitational Waves from a Binary Black Hole Merger B. P. Abbott et al., (LIGO Scientific Collaboration and Virgo Collaboration), Physical Review Letters 116, 061102 (2016). This figure shows the data (top panels) at the Washington and Louisiana LIGO stations, the predicted signal from Einstein's theory (middle panels), and the inferred signals (bottom panels). The signals matched perfectly in both detectors.

The Prairie Astronomer 21 The Bright Spots on Ceres Are Blinking

Jason Major, Universe Today

All right, maybe not blinking like but from a telescope right here toward or away from Earth— a flashlight (or a beacon on the on Earth. were expected, but other tippity-top of a communication fluctuations in brightness tower—don’t even start that Researchers using the High were also detected. speculation up) but the now- Accuracy Planet famous “bright spots” on the Searcher (HARPS) instrument “The result was a dwarf planet Ceres have been on ESO’s 3.6-meter telescope at surprise,”said Antonino Lanza observed to detectably increase La Silla detected “unexpected” from the INAF–Catania and decrease in brightness, if changes in the brightness of Astrophysical Observatory, ever-so-slightly. Ceres during observations in co-author of the study. “We July and August of 2015. did find the expected changes And what’s particularly Variations in line with Ceres’ 9- to the spectrum from the interesting is that these hour rotational period— rotation of Ceres, but with observations were made not by specifically a Doppler effect in considerable other variations NASA’s Dawn spacecraft, spectral wavelength created by from night to night.” currently in orbit around Ceres, the motion of the bright spots

Bright reflective material in Ceres' Occator crater, imaged by NASA's Dawn spacecraft in Sept .2015. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. The Prairie Astronomer 22 Watch a video below illustrating Since they are made of such Once day turns to night these the rotation of Ceres and how volatile materials though, hazes will re-freeze, reflected light from the bright interaction with solar radiation is depositing the particles back spots within Occator crater are likely the cause of the observed down to the surface— alternately blue- and red-shifted daily brightening. As the although never in exactly the according to the motion relative deposits heat up during the same way. These slight to Earth. course of the 4.5-hour Ceres differences in evaporation and daytime they may create hazes condensation could explain First observed with Hubble in and plumes of reflective the random variation in daily December 2003, Ceres’ curious particles. brightening observed with bright spots were resolved by HARPS. Dawn’s cameras to be a cluster “It has been noted that the spots of separate regions clustered appear bright at dawn on Ceres These findings have been inside the 60-mile (90-km) -wide while they seem to fade by published the journal Monthly Occator crater. Based on Dawn dusk,” noted study lead author Notices of the Royal data they are composed of some Paolo Molaro in the team’s Astronomical Society (full text type of highly-reflective materials paper. “That could mean that on arXiv here.) like salt and ice, although the sunlight plays an important role, exact composition or method of for instance by heating up ice Source: ESO formation isn’t yet known. just beneath the surface and causing it to blast off some kind of plume or other feature.”

Youtube link: https://www.youtube.com/watch?v=AN9MxTDyqww

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