[sac-forum] Call for Observations
- From: "AJ Crayon" <acrayon@xxxxxxx>
- To: "SAC Forum" <sac-forum@xxxxxxxxxxxxx>
- Date: Thu, 14 Jun 2007 09:32:34 -0700
Here is a head's up for contributing to the SAC newsletter. It is from the
last issue containing the list of objects for the next 3 months for Crater,
Serpens and Scorpious. The 3 months is used in an attempt to keep ahead of the
summer monsoon and its accompanying clouds and precipitation.
This will be the first and only pass at Crater, the wine goblet. I gave some
thought to not doing this constellation because there were no bright galaxies.
But eventually gave in as the faintest in our quest for this month is mag 11.8.
But don't let that fool you very much because some have low surface
brightness. Regardless all should be within reach of an 8" telescope from SAC
sites and, if you are an experienced observer, they can be glimpsed in a 6".
Our hunt this month begins in the southwest part of the constellation with
NGC3511, an elongated barred spiral. Ten arc-minutes east of southeast and in
the same 30' field of view will be NGC3513, another barred spiral but this one
is more face-on. For more on these two galaxies see the April 1996 Sky &
Telescope article Edge-on Galaxies of Spring by Tom Polakis. Now, hopping to
the north central part of the constellation, find NGC3672 - a late type
elongated spiral. If you have difficulty finding or observing these keep in
mind their surface brightness's are mag 13.5. Going south some more, find
NGC3887, a mag 10.6 somewhat round barred spiral galaxy. Pay particular
attention to your observations of its brighter middle. By staying somewhat in
the middle of the constellation try NGC3892, a fairly bright galaxy. Going
back to the southern part of the constellation look up NGC3957, an edge-on
lenticular galaxy. In the same neighborhood slew to NGC3962 that is
considerably bright. Finally NGC3981, at the western edge, is a nearly edge-on
spiral.
The constellation Serpens is divided into two parts, separated by Ophiuchus.
For this session the western part will be studied and the east will be saved
for another time. First for this session is the extremely faint globular
cluster Palomar 5. To get there, it is 29' in PA 172 deg from 4 Serpentis. If
you don't have a 20" or larger telescope try using a hood and averted vision
while waiting for moments of good seeing. Don't forget that lightly tapping
the telescope will help bring out the brighter stars. It probably won't have
the characteristics of a globular, but a few faint stars, that come and go,
should be good enough. After this gem the incomparable M 5 awaits. There
shouldn't be a problem locating and observing. If it is visible in your
finder, please include that in your comments. After these two globular
clusters it is all galaxies and we begin with the barred spiral NGC5921. At
mag 10.8 can you discern the bar, even if it is an elongated, slightly brighter
middle? Next, slew on over to NGC5957. This 11.7 mag galaxy has an NGC
designation of cometary. Do you agree? The next hop is to NGC5962, an 11.3
mag late type spiral galaxy. Slewing north about 4 deg and a little to the
west is NGC5970; a mag 11.5 late type barred spiral galaxy. Be careful not to
let the 7th mag stars interfere with your observation. The last two galaxies
are close to the eastern edge of this part of the constellation. Start with
NGC6070, an 11.8 mag that is joined by some pretty faint galaxies; but about
all we will see is the elongation. NGC6118 is the last, at magnitude 11.7. It
is the more elongated of the last two and, perhaps, has the lowest surface
brightness. So don't expect much.
In order to stay a step or two ahead of the summer monsoon the next
constellation in the monthly sequence will be covered in this column. It isn't
clear what I'm getting myself into but I'd like for us to do an observing
sequence on the Table of Scorpius. This is a magnificent section of this
constellation that stands out to the naked eye, is an excellent binocular area,
yet to review with a telescope is a very rewarding experience. While there are
a number of open clusters there are some interesting dark nebulae involved that
will add some variety to the process. NGC6242, to the northern part of this
section of sky, will be the beginning. It is bright and large so should be
easily found. Next is Trumpler 24 about a degree in size and containing some
200 stars. Involved in its northern part is the bright nebula IC 4628, it to
has several stars involved that belong to the cluster. Just to the west is the
rather elongated dark nebula Barnard 48. The SAC database indicates a UHC
brings out the bright nebula. Try this and let us know your results. Next
slew your telescope west, to Collinder 316, which almost involves all of Tr.
24. This cluster is about 1.5 degrees in size, but is rather scattered about.
Just to the west is the cluster NGC6227 that is 18', large and rich. Back in
1985 it was non-existent and is with SIMBAD, yet NED gave coordinates as 16h
51m 33.54s and -41 13' 50.2" which looks to be a 5th magnitude star in a rich
Milky Way Field. Are there enough stars in an 18' area to qualify as an open
cluster? Before leaving this area slew south to NGC6231, a cluster we have
already done, but not as part of this kind of observing sequence. This is a
2nd magnitude cluster and should be visible to the naked eye. Can you see it?
Continue your slew south and take a quick look at zeta 1 and zeta 2 area as
there are some pretty bright stars there. Finally slew farther south to SL 17,
another dark nebula elongated in a somewhat northern position. The SL
references the dark nebula catalog of Sandqvist and Lindroos.
We look forward to observations from all sizes of telescopes from members with
any and all kinds of observing experience.
See you at 5MM.
Clear skies,
aj
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