[sac-forum] Re: Saddle Mt tonight
- From: DBogan3220@xxxxxxx
- To: sac-forum@xxxxxxxxxxxxx
- Date: Sat, 18 Apr 2009 15:04:00 EDT
I was planning on coming out. If others were coming out too.
Dwight
In a message dated 4/18/2009 11:47:29 A.M. US Mountain Standard Time,
rvorbeck@xxxxxxx writes:
Is anyone going to Saddle Mountain tonight? I would like to know if anyone
else is going in order to make plans on being out there.
Ray
----- Original Message -----
From: _AJ Crayon_ (mailto:acrayon@xxxxxxx)
To: _SAC Forum_ (mailto:sac-forum@xxxxxxxxxxxxx) ; _AZ Observing_
(mailto:AZ-Observing@xxxxxxxxxxxxx)
Sent: Saturday, April 18, 2009 8:34 AM
Subject: [sac-forum] Saddle Mt tonight
Anyone going to Saddle Mt, or anywhere else dark enough to use a
telescope, here's a suggested observing list ripped straight from the SAC
Newsletter. And don't forget, if you observe them, send results to me for
inclusion
into the newsletter.
Time for a second trip through Lynx and the star of galaxy season. The
selections will include a number of barred spirals and, if the galaxy appears
elongated it should be the bar. We start near 27 Lyncis to find the
barred spiral NGC2500, which has a bright nucleus in the bar. Moving to the
southeast is NGC2537, the Bear Paw or Bear Claw Galaxy with asymmetrical
spiral arms. Now going a little to the north is NGC2541 another barred
spiral. The next galaxy, NGC2683, is in the 110 Best NGC and Herschel 400
lists.
Look for some mottling on the northwest side. Continue the eastward
trek to NGC2770 sometimes referenced as NGC2770A. It is a rather small late
type spiral and faintest on this list. Finally, the eastern most, is
NGC2776 an almost face-on barred spiral. The bar may not be easily seen yet
the
bright nucleus should be easier to detect.
We will now begin a two month observing session to better understand the
Hubble sequence of galaxies. Unfortunately, because of space limitations,
we will not be able to cover them exhaustively, nor will we be able to
discuss their many nuances. Yet there will be enough to give the observer
and
idea how the sequence relates to each other. The basic sequence starts
off like a tuning fork with ellipticals on the horizontal part; spirals such
as Sa, Sb and Sc on the upper part and barred spirals like SBa, SBb and
SBc on the lower part. The ellipticals are smooth featureless structures and
are shaped anywhere from round to elliptical, with some brightness changes
towards the middle. Spirals are flattened disk with stars forming
arm-like structures from a brighter central bulge. The barred spirals are
like
spirals but have a bar like structure emanating from the central bulge.
Its brightness normally falls between central bulge and arms. Please keep
in mind galaxies don't easily follow these divisions nicely as some are
difficult to categorize because they could be assigned to more then one class,
which leads to more classes and subdivisions. Selection criteria for our
galaxy study is based on orientation and magnitudes that are within reach of
SAC scopes. Ignore non-referenced field galaxies.
So, with the above introduction here are the next two month's worth of
observations. For June we begin with the E1 M105 in Leo then E7 NGC3384 aka
NGC3371 in Leo both in same field of view but ignore NGC3373. For spirals
start with the Sa NGC4429 in Virgo then the Sb NGC2985 in Ursa Major and
finally the Sc M99 in Coma Berenices. For July begin with the E1 M84 and E3
M86 both in Leo and in same field of view next is E4 M49 in Virgo. For
the barred spirals begin with the SBa NGC3227 in Leo then SBb M95 in Leo and
SBc NGC4535 in Virgo. Now which do you prefer, elliptical, spiral or
barred spiral galaxies? Personally I prefer spiral or barred spirals.
There are a plethora of others, which also includes irregulars and dwarf
along with the many subdivisions. For more study see
_http://en.wikipedia.org/wiki/Galaxy_morphological_classification_
(http://en.wikipedia.org/wiki/Galaxy_morphological_classification) that
covers lots more. See also
Luginbuhl and Skiff, Observing Handbook and Catalog of Deep-Sky Objects;
Kepple and Sanner, The Night Sky Observer's Guide and Steinicke and Jakeil
Galaxies and How to Observe Them.
I haven't checked the weather lately, has anyone done so and what does it
look like?
AJ Crayon
Phoenix, AZ
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