April 2016

Shallow Sky Object of the Month: Stargate Asterism

Original article appears in GuideStar May, 2016.

by Bill Pellerin

Object:  Stargate
Class:  Asterism
Constellation:  Corvus
Magnitude:  6.6 (brightest star)
R.A.:    12 h, 35 m,  59 s
Dec:    -12°  03’ 09”
Size/Spectral:  About 6 arc minutes
Distance:  35.9 ly
Optics needed: Small telescope

The first time I ever heard of the Stargate asterism was when I picked up a copy of John Wagoner’s 2013 observing list at the Texas Star Party. It seems that the asterism was mentioned earlier by the well known observer Philip Harrington in a May, 1998 article in Sky and Telescope magazine. (John may yet be the originator of the name, though.)

That’s not the earliest identification of this star grouping, though. I have written about the Struve dynasty of double (and multiple) stars in the past. In 1832, Otto Struve cataloged the pairs AB, AC, and BC. Additional pairs were cataloged after Otto’s death, but clearly he saw the collection of stars quite early on.

President's Message

Original article appears in GuideStar May, 2016.

by Rene Gedaly

HAS Women’s SIG Meet ’n Greet

HAS Women of all ages braved the weather to meet at Amelia Goldberg’s home for the first meeting of the HAS Women’s SIG. We talked about telescope workshops, observing the HAS Texas 45 as a group, the upcoming barn raising of the new bunkhouse, and some exciting possibilities for a December social—this in lieu of our typical meeting during finals week at the University of Houston. At present we’re a group of 17 members but there’s room for you! Contact [email protected].

In the know...

 

  • The Video Team is expanding. Welcome Mario Moreno! Mario will back up Rob Morehead as videographer and is an experienced video editor at Channel 13 TV.
  • Mike Edstrom and I signed the rental agreement for the last personal observatory lot. Wow. The Observatory & Dark Site is the place to be.
  • And how about this? The website saw 101,700 views in 2015. That doesn’t just happen. It takes teamwork and continuity. Thank you Web Technology Team: Heather Houston, Drupal Admin, User Support; Michael Murphy, Front end Developer, Look & Feel; Bill Krahmer, Back end Developer, Programming; and of course, Mark Ferraz, Webmaster and Web Technology Committee Chair.

Astronomy at Liberty High School

 

The Education & Outreach Team continue to broaden their mission of bringing astronomy education to the community, in this case to Liberty High School, a unique HISD Charter school that offers night classes (4P-10:45P) for 18-26 year old ELL students who are working diligently to earn a high school diploma after work.

A special thank you to Ray Gedaly, who spoke to Mr. Moult’s science class about the solar system. Steve & Amelia Goldberg, and Ray & Rene Gedaly, Joe Khalaf and Debbie Moran brought telescopes to show students the moon and Jupiter.

Astronomy truly transcends any language barrier.

President's Message

Original article appears in GuideStar April, 2016.

by Rene Gedaly, President

The GuideStar has a new editor. Bill Pellerin, editor and publisher of the HAS GuideStar for two decades, has turned over the reins to new editor Bob Wiesner. Welcome, Bob. For his tenure at the award-wining GuideStar, we honored Bill Pellerin with the President’s Exemplary Service Award. Thank you, Bill.

Ed Fraini: VP Facilitator. One of the advantages of membership in HAS is that its members bring with them some great skills. One of these members is VP Ed Fraini, and I’m not talking about the skills he puts to use at the dark site or the observing chops he’s honing as he makes his way to AL Master Observer status. No, I’m talking about the skills he brings from his day job, professional leadership development. Just take a look at our Vision statement. It sounds simple but it will inform every action the committees, directors, and officers take.

Don’t get dropped. Renew your membership now. We hold seminars at UH for those new to astronomy and for those with more experience. You can find an observing opportunity almost every week now. Our dark-sky site hosts educational programs for members, guests, and the public. And for you members who live online, access to recorded presentations, member photo galleries, and, this is a biggie, only members have access to the private HAS Facebook group. What a freewheeling space that is. Don’t miss out. Renew today.

HAS Women Meet ‘n Greet. It’s a get together for HAS Women Sunday April 17th beginning at 2 pm. Where? Centrally located at Amelia Goldberg’s home. Join us for a little food & drink and a lot of just plain getting to know one another. If you’re a female member of HAS, be sure to RSVP for location details.

Site Orientation Now Online! Thanks to all who made this happen, especially to John Haynes who authored and has been giving the same site orientation in person at UH. With progress comes the added convenience of online orientation, but also yearly testing, and that’s a good thing. All site users need to pass the test to get the new year’s site code. An additional special thank you to Mark Ferraz and the Web Technology team. Folks, it takes a lot of hard work to make it easy for the rest of us. We appreciate it.

Denebola — β Leo

Original article appears in GuideStar April, 2016.

by Bill Pellerin

Object:  Denebola — β Leo
Class:  Star
Constallation:  Leo
Magnitude:  2.14
R.A.:    11 h, 49 m,  04 s
Dec:    14°  34’ 19”
Size/Spectral:  1.75 Solar Masses, Color: A3
Distance:  35.9 ly
Optics needed: Unaided eye

The name of this star may seem somewhat familiar. There’s another star in the sky named Deneb, in the constellation Cygnus (the swan). The name Deneb is from the Arabic word dhaneb which means ‘the tail’.  The name Denebola is a combination of the Arabic words Deneb Alased, meaning the tail of the Lion, which, in fact it is. It lies at the eastern end of the constellation Leo the Lion.

The Bayer designation of β might lead you to believe that this is the second brightest star in the constellation, but not so. Regulus (α Leo) is the brightest and Algeiba (γ Leo) is the second brightest. What’s up? When Johann Bayer assigned these designations to stars in the early 1600’s estimating magnitudes was not something that could be done precisely. Bayer also made assignments based on the rise time of the star and other criteria.

His star atlas was titled Uranometria and the name derives from “Uranos”, a Greek word for ‘sky’ and “metria” (measurement).

Observations reveal that this star has a disk of dust surrounding the star. Are there extrasolar planets here? Maybe. This disk has been confirmed by images by the Herschel Space Telescope. Another effect of the surrounding material is that the spectra of the system show radiation in the infrared, mostly from this dust disk being heated by the star.

This star is considerably hotter than our Sun. At its surface (the photosphere) the temperature is estimated to be 8500 K (Kelvin) compared to our Sun’s temperature of 5800 K. Since color and temperature of stars are related (hotter stars are bluer than cooler stars) this star is ‘whiter’ than the Sun which is a G2V star.

Hotter stars have a shorter lifetime than cooler stars.

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