Tuesday, November 27, 2012

webspotting 28 - atlas of Andromeda

As published in the Dec 2012/Jan 2013 issue of SCOPE, the newsletter of the RASC Toronto Centre. Republished here with permission.


The Thursday night before the 2012 Annual Algonquin Adventure many Toronto and North Bay astronomers were able to enjoy the very good dark skies. I had my trusty 8-inch Celestron and, as I had been forbade by Phil Chow to view double stars, was tracking down faint fuzzies. Not far away was Adam Clayson and his Dobsonian telescope (the small one, I think). This beautiful reflecting 'scope has an 18" mirror and a focal-ratio of 4.5. Stunning views, easy to use. Adam employs excellent eyepieces to compliment the tremendous light gathering power. And, as he is want to do, he likes viewing deep sky objects. Very deep sky. In fact, he likes looking at deep sky objects INSIDE other deep sky objects.

While I was tracking down a few more targets from the Messier catalog, Adam took in some objects "close" to home, nebulae and clusters in the Milky Way. I wondered, out loud, how to find M33 naked eye. Adam quickly aimed the truss tube at it.

The 33rd object in Messier's famous list is often referred to as the Pinwheel Galaxy. But then M99 and M101 are also tagged with that moniker. The Triangulum Galaxy might suggest it has a peculiar shape; it does help us remember where the faint fuzzy is located. The prosaic label is NGC 598, in reference to the New General Catalog, with thousands of entries.

But, it was not the galaxy, per se, that Adam was interested in, that night. He was looking at, and sharing, objects within M33. In particular, he showed us NGC 604, a star forming region, at 66 power. I could see it! A brightening within a graceful arm of the canted spiral. A nebula within the galaxy. And then I started to really think about it. We were seeing a diffuse emission nebula, probably not unlike our Great Orion Nebula, in another galaxy, some 2.9 million light years away.

Adam was in his element. He briefly showed me a detailed paper chart with multiple targets identified (I forgot to ask him the source). When I returned to my computer and checked SkyTools, I found that I could make it show small objects within the oval outline of the spiral. M33 harboured at least 6 IC and 4 NGCs.

This all came flooding back when I caught the delicious APOD image on 24 October 2012. The host galaxy, this time, our sister, Andromeda, M31. About the same distance away. The object in question this time: the stellar association of young blue stars making up NGC 206. Wow. I promptly downloaded a copy for my screen saver.

Then I got to thinking, as the neighbour galaxy soars directly overhead every evening this time of year, what about going after some of these? If and when I have the privilege of using a "big gun," a 'scope with lots of aperture, when going deep, what shall I use? Even when I heavily tweak and coerce SkyTools, I can still only get it to show one NGC within M31.

By chance, I stumbled across a links page at another astronomy club. A compilation of favourite web sites. The one that caught my eye? The "Atlas of the Andromeda Galaxy." Ah ha! An atlas.


I surfed into the framed site by Paul Hodge and started looking for a map. My wish was quickly answered. Not one; there are 40 of them. Detailed annotated charts. And then I spotted the tables. Table A. Globular clusters within M31. There are over 300 items on the list! Those Mr Hodge catalogued in 1981.

This is all part of the LEVEL 5 site, a "Knowledgebase for Extragalactic Astronomy and Cosmology."

So, next time you're under dark transparent skies (if you can somehow avoid constant churning clouds) with some aperture at your disposal, why not go hunting inside a galaxy. And not the Milky Way.

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