The Asterism Observing Program has been updated with new asterisms to observe. Today, 5 new asterisms were added to the list, making the total number of asterisms to choose from 114. You only need to observe 100 to get the Program’s Award Certificate and Pin. Troy and Michelle Stratton’s goal is to have 200 or more asterisms on the list to choose from so the list will be constantly updated. Those working this new Observing Program need to check the Program’s web page often to see the latest additions and Asterism List.

By Bill Pellerin
Houston Astronomical Society
GuideStar Editor

It’s that time of year, again. You may be the one looking for a (relatively) inexpensive gift for an astronomy enthusiast. Or, YOU may be the astronomy enthusiast, and you may be asked what you’d like to receive as a gift. Fortunately, there are lots of possibilities. I wrote a similar article for the Astronomical League web site in 2011, and there are no items on this list that were on the 2011 list, so check them both out.
Happy holidays to all and clear skies in 2013.
Memberships
Astronomical League — Membership in the Astronomical League is often associated with membership in your local astronomy club. Go to the organization web site, test.astroleague.org, click on the ‘member societies’ tab and see if your club is part of the AL. If so, being a member of your local club makes you a member of the AL.
You can also become a member of the AL as an ‘at large’ member. Click on the ‘join’ tab for more information on this option.
Your local astronomy club – Being a member of an astronomy club is great – you can discuss your observing projects with others, attend presentations and meetings, and learn about astronomy related events in your area. Clubs often do outreach programs, introducing the public to the joys of amateur astronomy. The club may offer other benefits as well – an observing site, loaner telescopes, or classes.
American Association of Variable Star Observers – if variable stars are (or could be) your thing, you’ll want a membership in this organization. The AAVSO provides a lot of information to observers, and collects their observations into a database for use by other amateurs or professionals. www.aavso.org.
Association of Lunar and Planetary Observers – an organization of astronomers who observe solar system objects including the Sun, Moon, the planets, asteroids, comets, and meteors. www.alpo-astronomy.org.
International Dark Sky Association – an organization whose mission is to preserve and enhance dark skies by promoting environmentally responsible outdoor lighting. Become an activist in your area for dark sky. www.darksky.org.

Books
Books always are a good choice for a cold, winter night. Be sure to specify the format – hardback, paperback, e-book, or audio book.
Coming of Age in the Milky Way – By Timothy Ferris is my all-time favorite astronomy history book. This one has been out for a while (published 1988) but the story is so good and so well told you won’t be able to put it down. An abridged audio book is still available, so you can listen to it read by the author while driving to and from your observing site.
Binocular Highlights, Gary Seronik — the book you want to have when you want to observe, you’re in dark skies, and you have your binocs handy. Contains 99 objects with maps showing you how to find them with your binoculars.
The Observer’s Sky Atlas, Third Edition (Springer), E. Karkoschka — a remarkably compact (and not well known) atlas guides you to unaided eye, binocular, and telescope objects. You can throw this compact guide into the glove box of your car and always be ready to find some new and interesting objects in the sky.
The Day We Found the Universe, Marcia Bartusiak — The history of scientific discovery leading to the determination that the universe is larger than the Milky Way. It tells about astronomers who were close to establishing the size of the universe but who never put the pieces together and about Edwin Hubble, who did.
Cosmic Challenge (Philip Harrington) — Challenge your observing skills with this book. For any size telescope. Can you see the Horsehead nebula with binoculars? Phil says you can.
How Old is the Universe (David A. Weintraub) — How did we come to know the age of the universe with such certainty? Available as a paperback, an e-book, or an audio book.
The Backyard Astronomer’s Guide (Terence Dickinson & Alan Dyer) — anything by either or both of these guys is going to be good.  This one’s a comprehensive look at amateur astronomy from just getting started to sophisticated astro-imaging

Video
The Inexplicible Universe: Unsolved Mysteries (The Great Courses) – DVD—Neil deGrasse Tyson—six lectures on things we don’t understand in the universe — great for a cloudy night.
The Journey to Palomar (PBS Home Video) – A very enjoyable video detailing history leading to the construction of the Palomar observatory, the largest telescope in the world at the time.

Troy and Michelle Stratton have put together a new Observing Program, looking at famous stellar asterisms. For details of this wonderful program, see the web page at http://astroleague.org/content/asterisms-observing-program

Bill Pellerin

Houston Astronomical Society

GuideStar Editor

If you get into a discussion about the ‘best’ telescope, prepare for controversy. The right answer, of course, is that there is no one best telescope. There are telescopes that are better for the kind of observing you are doing (deep sky, planetary, double star, etc.), but how about the right telescope for the observing conditions you’re likely to find.

Here’s my story. On October 12, 2012 I was part of a group of amateur astronomer volunteers who did a star party at the Camp for All site near Brenham, TX, about 80 miles northwest of Houston. Camp for All is designed to provide a summer camp experience for children and their families with special needs. For this event we were showing the sky to children who are cancer patients. All public star parties are a great experience, but this one is especially rewarding for the volunteers.

The weather conditions for that day were not the best, but there were some breaks in the clouds and we had hope that the sky would clear in time for observing, which was scheduled between 8:00 p.m. and 9:00 p.m. The sky didn’t cooperate – clouds came and went and while a few stars popped out from behind the clouds from time to time, there was no consistent clear sky for us.

Knowing that these were the conditions we would likely have to work with, what’s the best telescope / mount to bring? Last year, when conditions were excellent I had my computerized alt-az 8” SCT at the site. Turn it on, find two stars to set it up, and it’ll find whatever I want in the sky and track it. I didn’t have to keep nudging the telescope to keep the object in view.

This telescope was a great choice last year, but it was a poor choice for this year. It didn’t work well at all, and it wasn’t because anything malfunctioned, it was because observing conditions were different. We had a 50 to 75 percent cloudy sky at the site, with a few stars shining through (notably Vega). The SCT system requires a two star alignment, and on a clear night it’s easy to accomplish. On a night where clouds are coming and going, alignment is virtually impossible. The ‘scope slewed to the vicinity of Alpheratz, said ‘center Alpheratz’, Alpheratz went behind a cloud, and so on.

I never was able to get the telescope aligned. I was able to manually point the telescope to the double cluster and show this to a few campers, but it wasn’t visible for long. The double cluster went behind a cloud.

What would have been better under these circumstances is an alt-az mounted manually pointed telescope – a Dobsonian or some other manual mount. With that kind of telescope I could have pushed it to, say, Mizar, a nice triple star system. Or to Albireo, a lovely double star in Cygnus. (Ok… I could have manually pointed the SCT as well, but it doesn’t lend itself to manual pointing easily.) I would, of course, have had to nudge the manual telescope from time to time.

So… what are the characteristics of a good telescope for these circumstances? The advantage to a computerized and motorized telescope is that it finds objects for you and it tracks them for you. Less fiddling is required during the observing session. This works if the sky is clear enough for you to get a good alignment. The advantage of a manually pointed telescope is that you can point it anywhere, easily, by hand and no alignment is necessary.

My conclusion: The best public star party telescope, especially if observing conditions are iffy, is one which can be manually pointed if necessary but has some pointing assistance capability if the sky allows you to do an alignment. I have an alt-az telescope mount with encoders and a small (deck of cards sized) push-to computer. If I can do a two star alignment, the push-to computer will tell me which direction and how far I have to push the telescope to get the telescope pointed to an object in its database. If I can’t do a two star alignment I can simply push it to some object I already know. I use a small wide field refractor with a on this mount so that the number of telescope nudges is limited and the distance I have to move the telescope is limited. This setup obliges me to select objects that show well in such an instrument, but there are plenty of those. Look in books and magazines for ‘binocular objects’ – these make great wide-field instrument objects.

I could have showed the kids some bright double stars (where the clouds cooperated), perhaps the Andromeda Galaxy, a bright cluster, or a planet (had there been any in the sky on that night).

The key to public star parties is to show the public some bright objects, have a story to tell about the object (how far, what color, the evolution of the object, etc.), and wait for questions. Be prepared to show where objects are in the sky with your green laser pointer and teach the observers about the object.

Bill Pellerin

Houston Astronomical Society

GuideStar editor

Note: This is a technical article about communication between your observing devices and your computer. The ASCOM Initiative only supports Windows PCs.

How long have you been fiddling around with computers and the devices connected to them (sometimes called peripherals)? If you’ve been doing this for a long time you may remember the old days when, if you bought a new piece of software, you had to be sure that the software would support (work with) your printer. That is, the software had to support or communicate directly to your printer and if it didn’t you were out of luck.

Fast forward to almost the current day. And think about astronomy software, in particular planetarium programs that control your go-to telescope. Until recently, if the software did not support your telescope mount, your imaging camera, your guiding camera, your focuser, or some other part of your setup you had a problem. One solution, a bad one, is to use the software that’s compatible with your device instead of the software you’d prefer to use.

The computer / printer problem got solved by offloading the task of communicating from the software to the printer to the operating system. The o/s communicated with a ‘driver’ (a small piece of software) usually provided by the manufacturer of the printer and the ‘driver’ established the communications with the printer. This arrangement made the development of application software easier because the manufacturer was no longer required to support a large number of printers, and it handed off the task of facilitating the communication between the application software (and o/s) and the printer to the printer manufacturer. The printer manufacturer had a vested interest is assuring that their product would work in that environment; nobody would be interested in purchasing a printer that they couldn’t use.

To some degree, we’re still in the dark ages with telescope systems (mounts, cameras, etc.). The software maker is obliged to make, for example, planetarium software work with a large number of telescope mounts to make it marketable. If your software and your telescope mount can’t talk with each other you’re stuck.

But, like the computer / printer problem was resolved by making the printer maker responsible for the final piece of software to enable communications, we’re now moving to a software model where the mount (for example) manufacturer is responsible for writing the ‘driver’ that allows the planetarium software to communicate with the mount. This frees the writer of the planetarium software to concentrate on the aspects of the software that relate to the functionality of the program.

The solution is called ASCOM (which means Astronomy Common Object Model). The idea is that the software maker creates programs that communicate in the same ASCOM compliant language and the device manufacturer (or an interested third party) creates a driver that interprets the ASCOM commands and converts those to commands that their device understands. Communication from the device to the software reverses the communication path; the ASCOM interpreter translates the communication from the device into language that the software understands.

Not all software and not all devices support this approach to establishing communication between the software and the device, but many do and if you need the capability that’s provided by this approach it can serve you well.

Why would you use ASCOM instead of the direct communication that the software provides? One reason – the software you want to use may not support your device directly, but may support ASCOM devices. In other words, it may be the only way to establish communication between your software and your device.

This is why I’m using ASCOM to enable communication between the camera control software I’m using and my imaging camera. The software I want to use for that purpose doesn’t directly support my camera, so the only way to make the communications work is via the ASCOM interface. The manufacture of the camera has provided an ASCOM ‘driver’ as the final puzzle piece that makes this work.

There’s another reason to use this as well. Telescope mounts have long used serial ports (COM Ports) for communication between the software and the device. (This is a bit of a relic, and many mounts are moving away from using serial ports.) The problem is that serial ports are a ‘captured’ by the software that’s using them. No other software can simultaneously use the serial port to connect to the same device. With ASCOM, the serial port is tied to the ASCOM driver, not the application software. The ASCOM driver can accommodate more than one communication path from software so two or more computer programs can communicate simultaneously to the device through the same ASCOM driver.

Why would you want two different software programs to be able to direct your mount to a particular position in the sky? Perhaps the two programs have non-overlapping capabilities. That is, maybe the first program has a great list of NGC objects and the second has a great list of variable stars. Both can be running simultaneously and can share the communication path to the telescope mount.

Saving the best for last, the ASCOM software is free from www.ascom-standards.org. If all this sounds complicated to set up and make work, all you need to know is whether there is an ASCOM driver for your device (telescope mount, focuser, camera, dome, filter wheel, etc.) and whether the software you want to use supports the ASCOM interface. If the answer to both those questions is ‘yes’, you’re good to go.

Much of the software that implements this capability is created by non-paid amateurs (some of whom are professional software developers) who then give the software away for free. These people have done a great service to the astronomical community. Thanks to them.

A work around: The planetarium software that I use does not support ASCOM. It does, however, support a similar, although proprietary, standard. A volunteer software developer created a piece of software that translates the proprietary communications to ASCOM which enables ASCOM communication to the telescope mount driver. Ok, it’s not as clean as we might like, but it works well.

Communication among astronomical devices is evolving, with some devices allowing Wi-Fi communications or wired network communications. I can see the coming of an OAN (Observatory Area Network) to complement the LAN (Local Area Network) and the WAN (Wide Area Network). With this capability installed the ability to control your telescope and other devices remotely is only a few short steps away. Even if those few steps are only the distance between the observatory and a warm room, this could represent a significant advance in amateur capabilities.

By Bill Pellerin

Houston Astronomical Society

GuideStar Editor

Amateur astronomy can get confusing, and for lots of reasons. Keeping up with who discovered what, how he or she named it, what it really is, and whether you can observe or image it is enough to make your head spin. So it is with the Struve family and the double stars that carry their name.

The Struve family had a lot of family members involved in astronomy for several generations from (1755 to 1992). Trying to sort through all the accomplishments of this family can be a challenge, so to keep it manageable we’ll focus on their work cataloging double stars. There are two members of the family we normally associate with double stars, Friedrich Georg Wilhelm (von) Struve (1793-1864) and Otto Wilhelm Struve (1819-1905) the son of FGW Struve.

FGW Struve lived in Europe his entire life and became a professor of astronomy at what was then known as Dorpat University in Estonia. While there he measured the position of double stars with a micrometer and published his ‘Catalog of New Double Stars’ in 1827.

Otto Wilhelm Struve was the head of the Pulkovo Observatory (Russia) until 1889. Otto continued the work of his father and has his own catalog of double stars — smaller than his father’s.

These are the Struve family members most associated with double stars. It is worth noting that a grandson of Otto Wilhelm Struve, also named Otto Stuve (they named him Otto to confuse us) lived from 1897-1963 and was the director of the Yerkes Observatory in Wisconsin and the McDonald Observatory in Texas. His PhD work was on spectroscopic double stars and was done at the University of Chicago. He does not appear to be a significant cataloger of double stars, however.

How to Find These Stars….

Six of the stars in the Astronomical League’s Double Star observing club have the designation Struve attached to them. Five are connected to the elder Struve and one is associated with Otto Struve. This is an excellent observing program. The objects are generally easy to see and often visually stunning. I completed the list in 1999, and I highly recommend it.

Here’s where observing the Struve stars can get complicated. The FGW Struve catalog of double stars is often designated with a sigma (Greek character) and then a number (example: Σ2470), but not always. The Otto Struve catalog double stars have the letter ‘O’, then the sigma character and then a number (example: OΣ123).

The famous Washington Double Star catalog (WDS) identifies double stars as WDS <ra_dec> (http://ad.usno.navy.mil/wds/). So, for the double star we’ve been using as an example (Σ2470), the WDS designation is WDS19088+3446, which means the star is at RA 19 deg 08.8 min / Dec +34 degrees 46 min. Since that double star was cataloged by Fredrich Georg Wilhelm Struve, the three-letter-identifier of the discoverer in the WDS catalog is STF (remember Struve The Father). You can find this star pair in the WDS catalog by looking for the text ‘STF2470’.

A double star in the WDS catalog that was discovered and cataloged by Otto Struve uses the identifier STT in the ‘discoverer’ column followed by the Otto Struve catalog number. You can import the catalog into a spreadsheet, parse the rows, and filter the list to see only the WDS stars that were discovered by STF or STT. Or, you can search the list for your star pair of interest using a search string such as ‘STF2470’.

When you filter the WDS catalog, you’ll find that 4394 double stars in the WDS catalog were discovered by FGW Struve and 996 star pairs in the catalog credit Otto Struve as the discoverer. (Note that the full WDS catalog has 118,444 entries.)

In TheSky (Software Bisque) you can find the FGW Struve stars as ‘Struve 2470’ or ‘WDS STF2470’ and the Otto Struve stars as ‘WDS STT123’. In SkyTools (Skyhound) the FGW Struve double stars are found using the ‘STF2470’ format and the Otto Struve double stars are found using the ‘STT123’ format.

An Observing Exercise

Finally, here is an easy observing exercise for you – one which allows you to see a pair of FGW Struve’s double stars in the same field of view (I found this in the book A Year of the Stars by Fred Schaff). These stars make up another double-double (similar to Epsilon Lyr) in Lyra and are worth the effort to find.

To find Struve 2470 / 2474 (also known as SAO 67870 and 67879) point your telescope at RA 19 h 08 m 56 sec and Dec 34 deg 40 min 36 sec — the approximate midpoint of the two star pairs. These stars are around 7^th to 8^th magnitude, so they are quite a bit dimmer than Epsilon Lyr.

Early observers of the night sky thought that Earth was at the center of the universe, but now we know better. There is no center of the universe. No matter, in many ways we continue to act as if we’re at the center of the universe. Many of the measures that we talk about as amateur (and professional) astronomers are based on circumstances that are unique to us, Earth, and our solar system.

Continue reading

By Bill Pellerin

Houston Astronomical Society

GuideStar Editor

Did you see it? Did you see it?

After reading a couple of books about the history of the Venus transit I was very eager to see the one on June 5, 2012, and I did. The most recent book I read was The Transits of Venus by William Sheehan and John Westfall. This book tells the history of Venus transits since the first one known to have been observed by Jeremiah Horrocks and William Crabtree in December of 1639. It’s a remarkable story of determination by those observers who timed the next pair of transits in 1761 and 1769 on the recommendation of Edmund Halley. Halley died before either of these transits. The goal was to determine the distance between the Earth and the Sun, which they did but without the hoped-for accuracy.

I began to wonder about the mechanics of the event. How were Venus and the Sun arranged in the sky, and how were they moving during the transit? Did the movement of the Sun or of Venus contribute more to the relative movement that I saw?

We’ve learned that these events are rare because the orbital planes of the Earth and of Venus are not the same. Only when the planes cross each other while Venus is at inferior conjunction does a transit occur. An inferior conjunction is when the orbit of an ‘inferior’ (closer to the Sun) planet is between the superior planet and the Sun. The next inferior conjunction will be on January 10, 2014, but Venus will miss the Sun by about 5 degrees, and there will be no transit. The next transit is in 2117.

Let’s do a replay of the June 5, 2012 event to understand what was going on. Observationally, we saw Venus attack the north-eastern edge of the Sun and then move slowly westward across the face of the Sun. For the purposes of this article, the movements are considered from the point of view of an observer on the Earth.

When Venus is at inferior conjunction the apparent motion of the planet is to the west with some motion to the north or south. I simulated all eight transits back to May 23, 1526. For every May or June transit, Venus’ apparent motion was to the southwest, and for every December transit Venus’ apparent motion was to the northwest.

What was the Sun doing? The Sun is reliably moving east in the sky (compared to the background stars) year-around with some additional movement to the north or south because of the tilt of the Earth’s axis. You only have to know about the motion of the Sun during the four seasons to understand the motion of the Sun during a transit. In spring, the Sun is moving to the north and it continues to do so until the summer (northern hemisphere) solstice (the first day of summer – June 20, this year).

So, while the Sun was moving mostly east, it was also moving a bit north during the most recent transit and the position angle of the Sun’s motion was 82 degrees, just north of due east. Remember that north is 0 degrees, east is 90 degrees, south is 180 degrees and west is 270 degrees. The Sun moved 15’ 50.86” east and 2’ 13.6” north during the time of the transit the total motion of the Sun was 16’ 2”.

Until about May 13, 2012, Venus was moving mostly to the east in the sky. Between that date and about June 26, 2012 Venus was moving to the southwest at a position angle of about 244 degrees. After June 26, Venus continued its eastward trek in the sky. During the transit Venus moved 10’ 06” west and 4’ 56” south, the total Venus movement was 11’ 14.3”.

The movement of the Sun and Venus were in more-or-less opposite directions, but not exactly. If you do the vector math the combined movement is 26’ 55”.

So, if you want to see the replay, and you have software on your computer that simulates the positions of Venus and the Sun accurately, you can set this scenario up and watch it play out. We’ve been told that we won’t see another Venus transit in our lifetime. That’s true, but we can watch the replay of the event on our computers as many times as we want. Johannes Kepler, Edmond Halley, and their contemporaries would have been astonished by this capability.

After the 2012 transit ended, I thought about the observers who will see the next transit in 2117 and I wondered what tools they will have at that time. Surely it will be an amazing time, and some of those observers will be thinking about the observers of the previous transit in June of 2012 and wondering what the event was like for them.

Thanks to fellow Houston Astronomical Society member Bill Flanagan who contributed calculations to this article. (Any mistakes are mine.)

(Kansas City, MO)–The Astronomical League is pleased to announce the top finishers in the competition for its Jack Horkheimer Service and Journalism Awards.  The Horkheimer Service Award competition is open to students under 19 and students 8-14 are eligible to apply for the Horkheimer Journalism Award.  All top finishers in the Jack Horkheimer Award program receive $1,000 in addition to a beautiful award plaque recognizing their special accomplishments.  More information may be found on the Astronomical League website test.astroleague.org.

The first-place winner of the 2012 Jack Horkheimer/Smith Award is Benjamin Palmer from Queensbury, New York.  Since the age of nine, astronomy has been his passion.  He applied for and was accepted as an intern at Dudley Observatory.  While at Dudley he participated in many large and small outreach events, with his enthusiasm for astronomy carrying over into organizing star parties for local high schools and the 4-H club during this internship.  Among his many activities, he is currently developing astronomy education software for classroom use and investigating the possibility of conducting virtual online star parties.  He is a member of the Albany Area Amateur Astronomers, Inc.

Benjamin has won an expenses paid trip to the national convention of the Astronomical League, ALCon 2012, being held in Chicago, IL July 4-7, where he will be speaking about his astronomical experiences and receiving the award.

The first-place winner of the Jack Horkheimer/Parker Award is Samantha Carter who lives in Fairview, Texas.  Samantha has been active in giving service to her astronomy club, the Texas Astronomical Society, and to the Texas Star Party, as well as coordinating astronomical activities for her own girls scout troop.  Currently she is working on the Astronomical League Messier and Urban Observing Awards.  

The first place winner of the Jack Horkheimer/O’Meara Journalism Award is Katelyn Skaer from Roswell, Georgia.  Her award-winning essay is entitled “A Star is Born.” Katelyn is a member of the Atlanta Astronomy Club. 

About the Astronomical League

The Astronomical League is the largest group of amateur astronomers in the world.  Its membership numbers 15,000 from over 250 clubs and individuals.  The mission for over 60 years has been to promote the science of astronomy by fostering astronomical education, by providing incentives for astronomical observation and research, and by assisting communication among amateur astronomical societies.  The organization is a 501(c)(3) non-profit entity.