This time I would like to talk about a second method of preparing for a night's observing. However, a star atlas is now required, and perhaps some books describing deep sky objects, variable stars, and double stars. I like the books put out by the Webb Society, but I mostly use the 3-volume Burnham's Celestial Handbook. I also use "Observing Handbook and Catalogue of Deep-Sky Objects," by Luginbuhl and Skiff. As to sky atlases, the only one to even consider for advanced amateurs is the Uranometria All-Sky Edition, 2nd Ed, revised. For the price of a cheap eyepiece ($60), this will be the best investment you ever made. Cloudy nights suddenly become fun with this atlas. And it comes with free shipping.
http://www.willbell.com/atlas/index.htm
http://www.willbell.com/atlas/index.htm
If you are among those who purchased the first edition, as I did, then realized the maps were all backwards and difficult to use in the field, have no fear. Things are corrected and much better now! And an all-in-one edition means only one volume is now needed to study Orion in depth! Okay, now that you have ordered and received your new star atlas, you may wish to continue to read this blog entry.
Before the 2nd edition of Uranometria came about, the following is how I used to do my 2nd Method of preparing for a session. In a moment I will tell you a new, improved way, thanks to the new atlas format.
1) Pick an area of sky of interest to you. With apologies, I will pick on oc 2232 in Monoceros once again, for reasons that should become apparent (it's a simple enough area to start with). However, any area will do, as long as you begin somewhere you will recognize.
2) Without looking at any photos of objects to be observed (wait until after you have actually searched for them at the eyepiece), write down some info about the main object from one of your resources. (oc 2232: 29'; stars mag 6--8, about a dozen).
3) Search on the map (chart #116 in Uranometria) for neighbouring points of interest. Write down any info about these objects you may have. You should notice oc 2219 to the east, oc 2250 to the west, and oc Cz 26 to the northwest. These are within easy star-hop range of oc 2232 (see my previous blog entry). Better yet, they are virtually undiscovered clusters. Their obscurity may or may not be deserved. You can decide for yourself. The size of your mirror and the darkness of your sky will help you determine this. A few unnamed doubles are also indicated nearby, as well as a handful of variables, including GL, V723, and IM. Don't ignore the brightest star within oc 2232 itself, which is labeled as a double star.
What we have just done is prepare our session considerably more than with the previous method, where we only needed the location of one bright object (and no atlas) to get started. This time we have gone target hunting, looking for specific objects near our bright starting point. Now, one of the reasons I chose 2232 again is that despite a good star-hop search in Method 1, those three other open clusters still may not have been found. They are faint, and at low power may be missed (if you found them using Method 1, then congratulations!). Using Method 2, we are now searching in an exact location for specific objects, hopefully with some success. Use neighbouring stars leading from 2232 and marked on the atlas to guide you directly. This is called guided star hopping.
Thus Method 2 works similarly to Method 1, but it is now required to choose an area of sky with a few other objects of interest near the main object. If you have the right atlas, this will pose no difficulty. Choose your area based on your sky conditions, horizon, and season. This is how I prepare for a session using Method 2. Now, however, I will sometimes do things differently.
Since the publication of the 2nd edition of Uranometria it includes, in addition to 220 star maps that show every NGC and IC object down to Mag. 15, plus every other deep sky object down to mag. 15 from other catalogues, there are 24 close-up maps at the back of the atlas. These highlight and enlarge x2 or x3 galaxy clusters (Virgo, Coma, Hercules and others), extra rich areas of the milky way (Cygnus, Sagittarius, Scorpius, etc) and the Magellenic Clouds. There is a lifetime of observing just within these supplemental maps! I can't wait to get at Cygnus this summer with Charts A1 and A2, and in the spring with the Leo galaxy charts (A10, 11). And once you see the Large Magellenic Cloud Chart and how many NGC objects reside there (a 2-page spread), you will want to book an astronomy B & B in Australia for a month.
Next time I will detail Planning Method 3. May you have clear skies and successful star hunting!
Mapman Mike
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