[sac-forum] Reminder

This is a reminder for submitting observations for the newsletter.  The objects 
are listed and taken from the latest issue.  If you get chance, make some of 
these observations and submit them for publication.

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 not listed in 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.

For October let's take on Lyra for the first time.  We are all aware of the gem 
there, but there's more to the Lyre than the Ring Nebula.  So, before getting 
there let's check what else there is to offer and start from the northern 
region.  First up, in the same 15' field of view will be the galaxies NGC6702 
and NGC6703.  The former will be the more difficult of the two, at mag 12.2 and 
about half the size.  For the next galaxy, slew to NGC6646.  This one is about 
2deg northwest from Vega.  For a change, go to the yellow and blue double star 
Struve 525.  Reminds you of Albiero, doesn't it?  Reason this was selected is 
due to the proximity to next selection, but I wanted you to stop and smell, I 
mean view, this one because it gets passed by on the way to the magnificent 
Ring Nebula.  Yes, just to make it clear M57 is next on the list.  There has 
been much discussion amongst amateurs and professionals about the visibility of 
its central star.  It is considered variable from 14th to 16th mag and, 
regardless, you will need a clear transparent sky for any chance at seeing this 
one.  Let us know if you see it - a simple yes or no should do.  Before ending 
there are two more observations on the list.  NGC6765 wonder of all wonders 
this is another planetary nebula.  Yes its magnitude is listed at near 13th, 
but don't let this stop you as it should be, at least, stellar in an 8".  The 
NGC description in the SAC database lists it as elongated.  Does this show up 
in larger telescopes?  After this you will understand why it is a little known 
planetary.  The final selection is the famous variable star RR Lyre.  Its fame 
comes from being called a standard candle that is its absolute magnitude has 
been well determined.  From knowledge of the absolute and visual magnitudes 
they are able to determine its distance.  Pretty neat!




Meanwhile enjoy observing and clear skies,
aj

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