What would it be like without stars at night? What is it we lose? Starry night skies have given us poetry, art, music and the wonder to explore. A bright night sky (aka light pollution) affects energy consumption, health and wildlife too. Spend a few minutes to help scientists by measuring the brightness of your night sky. Join the GLOBE at Night citizen-science campaign (www.globeatnight.org). The first campaign starts January 3 and runs through January 12.

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The Astronomical League has added another observing program for your viewing and educational enjoyment. The Observe Stellar Evolution Program will introduce you to 100 objects in various stages of evolution. The program has an observing manual, packed full of interesting information along with selected celestial objects to enforce the evolutionary nature of the cosmos. By completing this program, you will have a better understanding of the Hertzsprung-Russell Diagram and how the 100 objects of this program fit on the diagram. For more information, visit the Observe Stellar Evolution Program’s web page.

By Bill Pellerin
Houston Astronomical Society GuideStar Editor

What skills do you need to have to become an amateur astronomer? It depends on what you want to do as an amateur astronomer. I was thinking about this question as I recently upgraded the operating system on my computer. Doing so involves performing backups of the computer, establishing a back-out plan if the upgrade fails, testing the system after the upgrade, and resolving the odd problems that remain following the upgrade.

Since my computer controls my telescope mount, my imaging camera, and my guiding camera I needed to be sure that these capabilities were still functional after the upgrade. But, I’m getting ahead of myself.

If your observational activities are limited to basic observing and to pushing an alt-az mounted telescope to objects on the sky using a set of paper star maps, there are a lot of skills involved. You will have to learn how the objects in the sky move (as Earth rotates) and how to move the telescope to track these objects, how to set up and align a finder, how to collimate your (reflector) telescope, how to read star maps, how to star-hop to your object of interest, and how to confirm that what you see in the eyepiece is indeed the object you intended to find. You need to know the neighborhood – you must be able to look at the sky and pick out some major constellations and stars. In some, more dense, parts of the sky it may take some time to confirm the observation. You’ll have to have a plan, and a list of objects that are available to observe on that night and you need to know what to expect to see for each object. Is the object large and diffuse, or small and bright? Will filters help you pick the object out of the sky? Which filters?

If your telescope mount has an on-board computer you have to learn how to set it up and use it. Every manufacturer’s mount has a different setup process, and you’ll have to become comfortable with the process for your system over time. The setup may require that you know your latitude and longitude. You need to be able to convince yourself that the process worked as expected. The mount that I now use has a setup process that seemed ‘backwards’ to me when I first tried it. Over time, though, the process made more sense and I can now easily perform the process without giving it much thought. It’s a matter of teaching yourself these techniques; it’s like learning how to drive a car – not easy at first. Once the setup is complete, you have to learn how to direct the telescope to objects of interest. You have to understand what to do if the object you want is not in the object list of the telescope’s mount.

Are you going to control your telescope with an external computer? If so, you need to have some computer skills to set up the computer, to install the software, and to understand how to use it. You have to establish communications between the computer and the telescope mount. You’ll have to understand USB ports, serial ports (maybe), Ethernet networks (perhaps), and all the settings in the software you use to make the communications work. It can be challenging, and sometimes your best efforts end in frustration.

If you plan to be an imager, someone who takes photos of objects in the sky, you have to learn about cameras, filters, and camera control software. Depending on your imaging requirements you may have to develop expertise on how to use an autoguider and its associated software. Your skill set will need to include the ability to process your images, whether you’re doing photometry (brightness measurements), astrometry (position measurements), or images to hang on the wall. Learning and using high end image processing software will be in your future if doing this work is your goal.

As your observing system gets more complex there is more opportunity for things to go wrong and so you’ll have to have some troubleshooting skills. You have to learn how to isolate the problems and fix them. If your computer is not communicating with your telescope mount, why isn’t it? Did you forget to connect a cable? Do you have a defective cable? Is the cable wired correctly? Is the software misconfigured? Is the mount misconfigured?

There’s no requirement that we as amateur astronomers develop skills beyond those of finding and admiring objects in the sky. Those of us who want to do more will have to learn how to do more. It’s rewarding, but it requires adding to our skill sets and making the effort to do so.

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.