Hi all,
This month's offerings are a mixed bag of gems. Something for everyone whether you've got a scope or not.
Naked eye:
Scorpio Constellation: rather obvious for most, but if you haven't seen it before you won't forget it. At this time of the year it is directly overhead in the early evening. Its most distinctive star is its brilliant red heart, Antares.
Sagittarius Star Cloud, in Sagittarius. It is the densest star cloud of the entire Milky Way. You could be able to see this feature of the Milky Way from light polluted areas if you are able to shield out surrounding street lights. It lies in the direction of the centre of our Milky Way galaxy, it is actually located in the nearby spiral arm between us and the galactic nucleus. The Milky Way's centre lies some 30,000 light years in that direction. The star cloud is located just of the 'sting' of Scorpio, and right next to the M8/M20 complex. The big open star cluster M7 lies between this star cloud and Scorpio's sting.
Four planets in the Western sky. At the moment there is a conjunction of four planets occuring in the western sky during the early evening- Venus, Mars, Saturn & Mercury. Venus is unmistakeable just after sunset, the brightest 'star' in the sky. Just above it are two smaller 'stars'. The one on top of the trio is red in colour- Mars. The other 'star' then being Saturn. Mercury is difficult to spot as it is never more than 45 minutes above the horizon after sunset.
Telescopically Mars is not much of a show. It is receeding behind the sun as Earth has overtaken it in its orbit. Also being small in size, you'd be lucky to make out any type of planetary disk. Saturn, while too receeding, because it is much larger physically, its rings and disk are still resolveable. You may even see the shadow of the rings cast onto the planet. Harder to spot is the shadow of the planet's disk cast onto the rings behind it. Details within the rings is impossible as they are still too shallow in angle. They are slowly widening after last year being edge-on and invisible to us. They will continue to widen for the next 6 years before starting to close again. Mercury rarely has much to offer telescopically.
Easier targets:
M22, in Sagittarius. This globular cluster is one of the gems of the sky. It starts to resolve in smaller scopes. Interstellar dust occults its lluminosity by some 2 magnitudes!
NGC 6752, in Pavo. Another big globular gem that begins to resolve in 3" scopes.
More Challenging:
NGC 6744, in Pavo. A large face on barred type galaxy. Though large it has a low surface brightness. HII regions (nebulous star forming areas) & OB star associations (son-of-a-gun big stars) in its arms begin to become defined in scopes from 10" up. Its low surface brightness can make it tricky to find in a scope, yet binocuars will show it a little more easily from a dark site.
NGC 6876 et al, in Pavo. This galactic grouping contains something like nine galaxies, about upto six accessible to amateur scopes visually. NGC 6872 is a barred galaxy with its arms maybe just visible in larger scopes. The following link is to an amateur photo of the complex, with the lower image containing identifying graphics:
http://www.capella-observatory.com/I...GC6872EtAl.htm
NGC 2573, in Octans. A revisit from an earlier challenge, but its unique position in the sky I think makes it worth while for its nomination. This faint galaxy is very, very near to the South Celestial Pole, meaning it is visible year round from southern latitudes. I wasn't able to nail it in its last Challenge appearance, & I'm making it a priority for my observation program for this month. A really difficult bugger too.
Double stars, in Triangulum Australe. Rex has provided a list of doubles in the constellation Triangulum Australe in a zipfile link:
http://www.iceinspace.com.au/forum/i...attach/zip.gifTriangulum Australe Dble Stars.zip
http://www.iceinspace.com.au/forum/a...8&d=1280494551
Rex, not everyone can access this file, any chance of a non-zipfile form?
Planetary nebulae- IC 5148 in Grus, NGC 7009 (Saturn Nebula) in Aquarius, & NGC 7293 (Helix nebula) also in Aquarius. The first two relatively easy to spot. The Helix much more challenging as it has a very low surface brightness, despite its large size.
Speciallised target: Helios, the sun!
WARNING- NEVER look directly at the Sun through a telescope, binoculars or finder scope. Helios is a very special object. For once, the smaller the telescope, the better! That is because the Sun is bright enough for a small scope, and it limits the amount of heat collected by the instrument.
If you donot have a full apeture solar filter (if you don't know what this is, then you don't have one!), only 'projection' viewing is the safe option. If your scope is larger than 60mm in diameter, get a thick cardboard to totally cover your scope and cut out a hole no larger than 60mm in diameter, and place it over the apeture of the scope. Insert your longest focal length eyepiece here. Use a sheet of white paper, or card, to project the image of the sun onto this sheet. You will need to do your best by guaging the shadow of the sun along the length of your telescope. This projection method will suffice to see any Sunspots that may be on the sun's surface. Always keep both ends of your finderscope covered to avoid accidental glimpses into it.
Please add to the list of targets if you like, or ask about finding something inparticular.
Mental.