by Rex Parker, Phd director@princetonastronomy.org
November 12 Meeting
I’m back in Jersey after an exhilarating African safari last month, and am looking forward to seeing a good turnout at Peyton Hall Nov 12 for the presentation by Dr Joshua Winn of Princeton University (see Ira’s section below). Our dues-paid-up membership stands at 86 and counting. We’ve had several new members come aboard in the past few months, so if you have joined recently please introduce yourself at the break.
Farewell Prasad
As he prepares to leave New Jersey in a job-related relocation, I would like to give a big THANKS to Prasad Ganti on behalf of all the membership. Prasad has been associate editor for this publication for several years now, and his skill and dedication in editing and publishing Sidereal Times will be greatly missed, as will his participation as Keyholder at the Observatory. We wish you all the best in your future endeavors, Prasad, and hope you’ll stay connected with astronomy in the future.
8 Ways to Do Astronomy in AAAP
- Attend the presentations at Peyton Hall (2nd Tuesday each month)
- Give a 10-min member talk about your astro experiences (e-mail to program@princetonastronomy.org)
- Observe with state-of-the-art equipment at the Observatory
- Saturday night telescopes with members at WC State Park (see October Sidereal Times)
- Borrow the club’s SX Ultrastar color CCD camera to use with your own scope
- Get a Skynet account and do remote astrophotography from home (see below>)
- Go on an astro field trip with AAAP (recent trips include US Naval Observatory, Smithsonian Air & Space Museum, Princeton Plasma Physics Lab)
- Propose a field trip based on your own ideas and dreams
Andromeda!
To seek out Andromeda the constellation in the autumn sky has always been compelling – but perhaps a little mysterious too. For me the mystery stems from the lore of Greek mythology, which needs to be retold over and over as worthy legends do. Andromeda was the daughter of the king Cepheus and his wife Cassiopeia of ancient Aethiopia. Queen Cassiopeia boasted that Andromeda’s beauty even exceeded that of the Nereid sea nymphs, Poseidon’s minion, invoking the wrath of the god of the sea and storms. Poseidon thus sent the sea monster Cetus to ravage Andromeda as punishment for Cassiopeia’s hubris. It was the great hero Perseus himself who then rescued Andromeda as she was chained to the rocks by the sea, which is how he came to be her husband. Today many of the principals in this legend have a constellation named for them!
Figuring out exactly which stars are in the constellation is also part of Andromeda’s mystery (Figure below), even though it was first catalogued by Ptolemy in the 2nd century. It has no first magnitude stars, with Alpheratz, Mirach, and Almach all 2nd magnitude. I had always thought (until now) that Alpheratz was part of neighboring Pegasus since it forms the NE corner of the great square of Pegasus, but officially Alpheratz is considered part of Andromeda. But today Andromeda is probably better known as home for the Great Galaxy, Messier 31, the nearest large spiral galaxy to our own at ~3 million light years distance (red arrow in Figure). This spectacular deep sky object is for most people the first galaxy seen outside our own Milky Way and is the only spiral galaxy that can be considered a definite, obvious naked-eye object.. It is often said that the Milky Way galaxy’s appearance to an observer located in the Andromeda galaxy would look much like M31 does to us. According to Robert Burnham (Burnham’s Celestial Handbook), the Andromeda Galaxy was documented long before the invention of the telescope, mentioned in Persian writings from 905 AD. The first record of a telescopic observation was from Simon Marius of Germany in 1611, when he compared it to “the light of a candle shining through horn” (Burnham). This is a fairly accurate visual description even today for telescopes using eyepieces. However, the advent of astrophotography changed all that.
The constellation Andromeda is home to the Great Galaxy known as Messier 31 (red arrow). Figure from TheSkyX software.
In the middle of November in central NJ, the Great Galaxy in Andromeda transits (reaches is maximal elevation in the sky) at 9PM and is very close to the zenith. It’s placed splendidly for optimal astrophotography, which is better done with small amateur scopes than large, due to its immense size spanning ~3 degrees (6 times the moon’s diameter). Using a portable 3” refractor (Takahashi FC-76, focal length 600 mm) and a one-shot color camera (ZWO ASI-091), I photographed M31 the week before Halloween (Figure below). Note that two other galaxies are also in this image – M32 is the round object below the M31 core, and M110 in the upper right displays a hint of spiral structure. The final image here is the result of 17 x 20 minute subframes (total exposure 5.6 hours). All of the equipment to take photos like this is available to AAAP members at the Observatory!
The Great Galaxy in Andromeda, Messier 31, photographed with a small telescope in central NJ. North is up. Astrophoto © RAParker.
Skynet Remote Imaging for AAAP members
A good way to get going in astrophotography and learn more about how modern astronomy is done is to check out Skynet, a unique benefit of AAAP membership not offered by other astronomy clubs in the region. In June we renewed the contract with UNC-Chapel Hill for another two years. Skynet is the brainchild of Dr Dan Reichart of the Physics and Astronomy Dept at UNC-Chapel Hill. The internet-based queue scheduling software program runs on UNC computers to connect a system of observatories established for remote imaging. The Skynet Robotic Telescope Network comprises more than a dozen telescopes around the world in Chile, Australia, Italy, Canada, and the US. Each telescope is set up with robotic tracking mount, CCD camera, and filters for remote image acquisition. Tutorial videos are made available when you obtain a user account.
For both beginning astronomers or seasoned observers, Skynet’s easy-to-use interface taps into an extensive hardware network and large database of celestial objects from the Messier and NGC deep sky catalogs. It includes a basic image processing program “Afterglow” that runs on the server so you don’t need any special software on your computer. If desired you can download the data files and process the images you obtained at home on your own PC. Skynet is intended as an introduction to modern astronomy and astrophotography, and is used by science students at UNC and other institutions. Interested AAAP members are urged to take advantage of the club’s paid investment in this technology. Send me an e-mail note to get your Skynet user account at no cost to you as an individual. Email director@princetonastronomy.org
The November meeting of the AAAP will be held on the 12th at 7:30 PM in the auditorium of Peyton Hall on the Princeton University campus. The talk is on The Transiting Exoplanet Survey Satellite by Professor Joshua Winn of Princeton University.
Amateur Astronomers Association of Princeton 