Established 1999

FEBRUARY 2020 Volume XX Number 2 OBSERVE - LEARN – SHARE

Contents Upcoming Events

February 22 1 Upcoming Events • Star Party 2 Monthly Meeting O’Brien Dark Site • Stargazing at Jesse Jones Park & Nature 3 Club News Center (Outreach Event) • Messier Challenge (February 22 – March 30) 4 Gallery February 26 Trails as Parks Star Party (Outreach Event) 5 The (Part 1) Pundt Park February 28 9 February Star Party Telescope Workshop Lone Star College – Kingwood 11 Announcing the 2020 Messier March 6 Public Challenge Insperity Observatory 13 Dark Site Information March 9 NHAC Board Meeting 14 Insperity Observatory Insperity Observatory March 13 15 About NHAC Messier Marathon Orientation Humble ISD Collaboration Center

16 , Membership, Officers March 21 Messier Marathon, Star Party and BBQ

17 Affiliations (weather backup on March 28) O’Brien Dark Site

March 25 Trails as Parks (Outreach Event) Pundt Park March 27 Novice and General Meeting Lone Star College – Kingwood

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ANNUAL TELESCOPE WORKSHOP February 28, 2020

The February meeting of the Houston Astronomy Club will be a telescope and equipment workshop. Do you have a new telescope, or maybe an old telescope that you’ve been meaning to pull out, brush the dust off and learn how to use? If so, bring your telescope and equipment and let’s get started. NHAC encourages everyone to get out and sky watch in 2020!

The workshop will begin at 6:30 PM, Friday February 28 at our regular meeting place:

Classroom Building A – Room 112 Lone Star College-Kingwood 20000 Kingwood Drive Kingwood, TX 77339

Get help setting up and learning to use your new or old, telescope, mount, eyepieces and other gear. Ask questions and learn from club astronomers.

Beverages will be provided and feel free to bring your own snacks.

Invite friends, family, or anyone with a telescope. Hope to see you there!

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Outreach in 2020 NHAC Commemorative T Shirt Harris County Precinct 4 has scheduled a The NHAC 20th Anniversary commemorative number of astronomy-related public events T shirts will be available soon. this year for which NHAC will provide assistance. These will be good opportunities for NHACers to share their knowledge and enthusiasm, and generate interest in the NHAC 2020 Calendar Club. These events are typically held in Pundt are $10 and are available to Park, Jesse Jones Park & Nature Preserve and purchase at the monthly club meetings. Kickerillo-Mischer Preserve, all of which are in northern Harris County.

See the calendar at the NHAC Website for dates Astronomical League Matters and more information. These are outdoor Learn about the League’s programs at the events and are weather dependent. Cliff Astronomical League Website. The NHAC Herseim and Aaron Clevenson will provide Coordinator is Aaron Clevenson, at NHAC coordination and will advise of any [email protected] . changes or cancellations via email.

We welcome news, photos, comments and The latest issue of "What's Up, Doc" by Aaron contributions for North Star, the NHAC Clevenson is at What's Up, Doc? newsletter. Please send them to [email protected] by the 10th of each month.

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Image by Joana Tan, NHAC

Back on the moon, Nov. 2, 2019 Location: The Woodlands, Texas Transparency: 3-4 Seeing: Good Single shot via 40mm eyepiece through 8" Celestron EdgeHD using Samsung Note 9

Image by Dick Locke, NHAC

I captured this colorful image Monday 1/6/2020 at 5 p.m. after noticing that something interesting was going on as I drove home. I applied an HDR blending technique in Photoshop to preserve detail and enhance the colors. Equipment: Nikon D850 camera & 500mm lens, f11, ISO 500, resting on my car window.

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By James Barbasso, NHAC

This is the first of a two-part series on Armillary Spheres. This month I will present the history of the Armillary Sphere. Next month, I will describe how I built my own Armillary Sphere. I have been fascinated by this ancient astronomical instrument and always want to own one. So, I embarked on the journey to learn about them. They are present in mostly artistic renditions in modern times, but how did they come about?

The word ‘armillary’ means circle or bracelet in Latin. The basic construction of the armillary sphere consists of graduated circles and usually a sphere in the center representing Earth. This was used to depict the motion of the constellations and around the Earth, as an Earth-centered universe was the accepted belief prior to the invention of the telescope in the 17th century. Early astronomers and astrologers could use the device to determine celestial positions at any time of the year.

Their history extends from China, Greece and the Middle East.

China

Throughout Chinese history there has been a keen interest in the stars. They created , to help them depict the stars that were observed, and used their knowledge of the heavens to predict astronomical events that would take place at certain times of the year. Astrology was also important in ancient Chinese culture, hence, the importance of predicting what time of year certain celestial objects appeared and their relationship to other objects in the sky.

Astronomers Shi Shen and Gan De developed one the first armillary spheres around the 4th century BCE. It was a primitive, single ringed object, whose ring passes through the Earth’s poles. That permitted ancient astronomers to measure right ascension (RA) and declination. In 52 BCE, the first permanently fixed equatorial ring was added by astronomer Geng Shouchang. This increased the accuracy of predicting RA. By 84 AD astronomers Fu An and Jia Kui added an ring. Now, the position of planets and constellations could be predicted more accurately.

Statesman, astronomer; mechanical engineer Zhang Heng added the horizon and meridian rings to complete the armillary sphere. The horizon permitted a visual of which objects are visible during the day or night and the meridian can show where on Earth objects will appear. He also created the

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world’s first water-powered celestial globe in 323 AD. This incorporated a water powered clock, which already existed.

Astronomer Kong Ting arranged the ecliptic ring to be pegged onto the at any point. Throughout the Tang dynasty (618 to 907 AD) several different armillary sphere variants were designed, each having a special purpose. These devices became quite a marvel of engineering and design, especially, when the water clock was incorporated into the working of the armillary sphere.

The original diagram of Su Song's book Celestial globe Qing Dynasty (1636 – of 1092 showing the inner workings of 1911) his clocktower; a mechanically rotated armillary sphere crowns the top.

Greece

Armillary spheres were present in the Hellenistic world and ancient Rome, dating back to the Greek astronomer (190 to 120 BCE), who credited (276 to 194 BCE) as the actual inventor.

The Greeks used the armillary sphere as a teaching aide around the 3rd century BCE. An armillary sphere with nine circles did not exist until the 2nd century AD, during the Roman Empire existed.

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Middle East

The Muslim religion was very keen on understanding the movement of the stars and planets in the heavens. Persian and Arab astronomers produced a precursor of the armillary sphere called the . This device was an analogue computational device used to solve astronomical and navigational problems. They had a flattened plate version for this purpose.

Muslim astronomers also invented the celestial globe, primarily used to solve celestial calculations, probably around the 11th century. The right ascension and declination of stars can be determined by finding the location of the observer on the meridian ring.

The spherical astrolabe from Astrolabe of Jean Fusoris [fr], made medieval Islamic astronomy, c. in Paris, 1400 1480, in the Museum of the History of Science, Oxford

The Renaissance period advanced the design of the armillary spheres in the 14th and 15th centuries. Once the telescope was invented and the scientific community accepted a sun centered solar system, the armillary sphere become obsolete as a scientific instrument.

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Today, the armillary sphere has become more of an art form. Its form can be recognized in outside artworks and even household lamps and chandeliers.

Armillary Sphere 1594

Note: all images come from Wikipedia https://en.wikipedia.org/wiki/Armillary_sphere

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By Rusty Hill, NHAC

Hi Folks.

It has been a difficult thing to find clear , other than just after a passing cold front, but the cold fronts do usually provide a two-day window of good viewing. But humidity is often a factor, and I would like to talk about that. This does require some discussion of the “relative humidity percentage”, and how it affects dew.

The more water in the air, the more easily dew can form, and that is our enemy in observing. There are several ways of expressing the amount of water in the air, but the most useful to us, and the most easily available, is the relative humidity percentage. A definition full of scientific gobbledegook is available, but the most easily understood description of the term is that it is the amount of water vapor in the air at the given temperature, as a percentage of the maximum amount of water vapor the air could hold at that temperature. This is the relative humidity percentage.

Let’s break this down. There will always be some amount of water vapor, great or small, in the air. The warmer the air, the greater the amount of water vapor the air can hold. Conversely, the cooler the air, the smaller amount of water vapor the air can hold.

If the amount of water vapor in the air remains constant, and the air cools sufficiently, we will reach a temperature such that the air is fully saturated with water vapor. This temperature is known as the “dew point”. If we cool the air just a tiny bit more, dew will start to form. The air has cooled to a point such that it cannot hold as much water vapor as is present, and the “excess water vapor” falls out of the sky in tiny droplets. This can be seen as dew forming on objects, such as telescopes.

To clarify this concept: It is not necessary for there to be an increase in the amount of water vapor present. There can be dew forming with a simple drop of temperature. The changing temperature can cause dew to form, without any change of the amount of water vapor.

Obviously, there can be changes in the amount of water vapor present, and this would also affect the relative humidity. This does not change the basic concept:

Dew forms when the water vapor present is greater than the air can hold at the given temperature. The excess water vapor condenses and forms tiny water droplets. These become the dew you see on your telescope.

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More next month if you are interested, but for now, enough of that!

Now to the February 22 Star Party…

If we are lucky enough to have good skies, when it starts getting dark the very prominent constellation overhead will be Taurus, with the triangular “head”, featuring the very bright red star Aldebaran. Taurus is the home of M1, the Crab Nebula. Just southeast of Taurus the Orion Constellation will be spectacular. It is the home of M42, the Great Orion Nebula.

Further southeast will be the brightest star in the sky, Sirius, in Canis Major. Other quite bright stars will be Capella in Auriga, Procyon in Canis Minor, Pollux in Gemini, and Regulus in Leo.

To the northwest, M31, the Andromeda Galaxy, will be visible. In another month it will be not quite as visible, due to atmospheric extinction as it drops lower toward the horizon.

All this depends on having decent skies. Right now, the forecast does not look promising. We shall see.

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By Rusty Hill, NHAC

Due to the unpredictability of the weather affecting the Messier Marathon:

NHAC is establishing a 37-night Messier Challenge window of opportunity to observe as many Messier Objects as possible. The 37 nights will start on a Saturday at noon and end at noon on the Monday 6 weekends later. This allows 6 Saturday and Sunday nights, as well as the 5 weeks in between.

We have planned the Challenge to avoid the Full Moon to the extent possible, include the two New Moons, and coincide as much as possible with the "Prime Season" for being able to observe all the Messier Objects in one night. This "Prime Season" is Mid-March through Early-April. Unfortunately, this year the April Full Moon is on April 7, which wipes out the evenings for the 10 or so days prior to April 7.

Due to the Lunar Cycle dates, the dates this year for the Messier Challenge are a compromise. I am proposing to have a schedule starting at 6 P.M. on Saturday, February 22, and ending at 7 A.M., Monday, March 30. This will include two New Moons, two Star Parties, the Messier Marathon, as well as the Backup Messier Marathon.

The intent of the Marathon is to view the Messiers in one night. The intent of the Challenge is to view them over the course of the 37 nights. If you desire to, you can do both!

The rules for the Messier Marathon and the Messier Challenge are somewhat different. If you observe during the Regular or Backup Messier Marathons, which is during the Messier Challenge, you need to be certain which set of rules you are following on that night. All observations using the Marathon rules will count towards observations for the Messier Challenge, but not vice-versa.

We are changing a rule that all sightings for this Messier Challenge must be from the O'Brien Dark Site. We are going to have two categories of entrants: O’Brien Site, and elsewhere, but not the Insperity Observatory.

We will have Club awards for First, Second and Third Places for total counts in each category, and a Special Award like a pin or small trophy for any and all club members who log all the Messier objects during the Challenge.

Given the reality of the era in which we live, go-to telescopes may to be used for the Challenge. Our intention is to promote success in observing by club members, and to familiarize the membership with

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the advantages of the O'Brien Dark Site, not to have obstacles to success. This will also encourage members to become more familiar with their equipment. There will be assistance by other members, if sufficient notice is given.

We will ask the O’Brien’s for a blanket clearance for access to the Dark Site for these 37 nights, subject to weather and pasture conditions. We do not want to tear up the pasture, and we equally do not want anyone to get stuck. I (Rusty) am proposing we establish a procedure for all members to coordinate with someone, probably James Billings or myself (Rusty) when arriving at the Dark Site and also when leaving. If you are observing elsewhere, you are on your own.

Do not hesitate to ask for assistance. Have fun, and Good Luck!

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If you are new to the club, Star Parties are especially for you. We, the members, are the reason we have observing Star Parties, and they are great occasions to get familiar with observing. We have 10" Dobsonian telescopes available at the Dark Site for your use. There will also be several other scopes available for all to try. And do bring a Binocular-- you can do lots of successful observing with nothing more.

NHAC Club Policy is that the focus of the Star Parties will be to give as much assistance as possible to new observers. For those who may not have been to the O'Brien Dark Site, it is just north of Dobbin, which is on Highway 105 of Montgomery. It has reasonably dark skies and a great low horizon in all directions. The Owners, Tim and Wanda O'Brien, are very generous hosts, and they do turn off any outside lights which might bother us, if we remember to ask.

The specific Dark Site location is password protected. Any club officer can give you the password, but it is NOT FOR THE GENERAL PUBLIC!

Access to the Dark Site must be requested from the O’Brien’s in advance via the NHAC email. It is only necessary for any 1 member to request access… Access approved for any of us is access approved for all of us.

On our NHAC web site, click on "Observing" then select "O'Brien Dark Site". Scroll down to the O'Brien Dark Site information and look for the "detailed directions" link. You will need to enter the password. There are maps as well as directions. It is well worth the drive, which is about 6- or 7-minutes driving time north of Dobbin off of State Highway 105 west of Montgomery.

Star Parties are routinely scheduled for the Saturday on, just before, or just after the New Moon throughout the year. This is to provide the best opportunity for dark skies.

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The next Public Night will be on Friday, March 6, 2020

Doors will be open by 6:15 PM and remain open to the public until 10:00. Sunset will be at 6:24 PM. The 12-day old moon will be about 90% illuminated and will be in the eastern sky.

These Public Nights are a great opportunity for us to be a part of astronomy outreach, and to observe with scopes we might never get to use otherwise. The Observatory has a 6" Takahashi refractor, a 16" Meade Schmidt-Cassegrain, and a 20" Plane Wave telescope. Each is computer controlled, and provides an awesome view of the sky. There are usually about 75 to 100 guests, sometimes more, on Public Night, with many repeating. Our guests are very appreciative of the opportunity to enjoy the sky and also expose their kids to astronomy. After all our guests have departed several of us usually stay for a while and enjoy the views and each other's company. This can be an opportunity to see a new or favorite object in a large telescope.

The Observatory is about 3/4 of a mile south of Will Clayton Parkway on S. Houston Ave, just north of Rankin Road in Humble, in the back part of the Jack Fields Elementary School on the East side of S. Houston Ave. The address is:

Jack Fields Elementary School 2505 S. Houston Ave. Humble, TX 77396

For more information, the Observatory phone number is 281-641-STAR and the web site is https://www.humbleisd.net/observatory.

Dates and times are subject to change.

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The North Houston Astronomy Club (NHAC) is a not-for-profit organization established in 1999 for educational and scientific purposes, for people of all races, creeds, ethnic backgrounds and sex. Our primary purpose is to develop and implement programs to increase the awareness and knowledge of astronomy, especially for those living near the north side of Houston, Texas.

NHAC is dedicated to providing an opportunity for people to pursue the science of astronomy, to observe in a dark-sky site, to learn the latest technology, and to share their knowledge and experience, thus our “Observe- Learn-Share” motto.

Public meetings are normally held each month on the fourth Friday. In the months of October, November and December they are usually rescheduled for the third Friday of each month, so as to not conflict with the Annual All Clubs meeting, Thanksgiving, or Christmas.

The benefits for membership include:

➢ Loaner telescopes after being a member for 6 months. ➢ Opportunity to observe from dark sky observing sites. ➢ Learn from experienced observers. ➢ Astronomy Magazine subscriptions at a discount. ➢ Astronomical League membership, with its many observing programs. ➢ Subscription to the Astronomical League magazine "Reflector". ➢ Access to the NHAC library ➢ Discounts on purchases at Land, Sea and Sky. Be sure to identify yourself as an NHAC member.

More information at the NHAC Website

Check out our Facebook page.

Our mailing address is:

North Houston Astronomy Club Post Office Box 5043 Kingwood, TX 77335-5043 NHAC is sponsored by:

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2020 NHAC General Calendar Executive Board Star Party General Meeting Meeting February 2020 Feb 22 Feb 28 March 2020 Mar 9 Mar 21 (and BBQ) Mar 27 Messier marathon Mar 28 weather backup April 2020 Apr 18 Apr 24 May 2020 May 11 May 16 (and BBQ) May 22 June 2020 Jun 20 Jun 26 July 2020 Jul 13 Jul 18 Jul 24 August 2020 Aug 15 Aug 28 September 2020 Sep 14 Sep 12 (and BBQ) Sep 25 October 2020 Oct 17 Oct 23 November 2020 Nov 9 Nov 14 (and BBQ) Nov 20 December 2020 Dec 12 Dec 18 Dates and times are subject to change. Star parties are weather permitting.

Membership 2020 NHAC Executive Board

Memberships run from January 1 President Carlos Gramajo - email through December 31. Vice-President Bruce Pollard - email Secretary Rusty Hill - email Full year dues are: Treasurer Joana Tan - email Students $10 Newsletter Editor Jesse Roberts - email Individuals $30 Astronomical League Aaron Clevenson - email Family Groups $40 Coordinator

Webmaster Bruce Pollard (interim) - email Membership applications and dues Observation Chair James Billings - email payments can be made at the NHAC website at: Membership Chair Hagen Miller - email NHAC Website Program Chair Trevor Arnold - email

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NHAC is a member of:

The Astronomical League

https://www.astroleague.org/

Night Sky Network

https://nightsky.jpl.nasa.gov/

International Dark Sky Association

https://www.darksky.org/

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