In blog #120 (M 103) I talked about a way of getting to know
unfamiliar parts of the sky by using a bright deep sky object as a jumping off
point for telescope users. Exploring
slowly and carefully in different directions has always been a worthwhile way
to spend time with the night sky.
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 still often use the 3-volume Burnham's Celestial Handbook.
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.
If you are among those who purchased the first
edition way back when, as I did, then realized the maps were backwards and
difficult to use in the field, have no fear. Things are corrected and
much improved now! And an all-in-one edition means only one volume is now
needed to study Orion in depth! Before the 2nd edition of Uranometria
came about, I used to do the following for my 2nd Method of preparing for a
session. Afterwards I will tell you am alternate, improved way, thanks to the
revised atlas format.
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 preceding, oc 2250 following, and
oc Cz 26 north following. These clusters are within easy star-hop range
of oc 2232. Their relative 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, along with
your experience as an observer. 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, which is labeled as a
double star.
1) Pick
an area of sky of interest to you. I
will pick oc 2232 in Monoceros, for reasons that should become apparent if you
glance at the atlas (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). I use the companion
volume to the Uranometria atlas (see the link, above).
https://upload.wikimedia.org/wikipedia/commons/f/f4/NGC_2232.png
What we have just done is prepare our session
more in depth 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. One of the reasons I chose 2232 is that despite a good star-hop
search using 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, and
with practice can be a very quick and efficient method of getting
around. 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. As
mentioned at the beginning of this article, however, I will sometimes do
things differently now.
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, 24 close-up maps at the back of the atlas.
These highlight and enlarge x2 or x3 things like 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 or Chile for a month!
Mapman Mike
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