View Single Post
Old 03-07-2011, 02:01 PM
Paddy's Avatar
Paddy (Patrick)
Canis Minor

Paddy is offline
Join Date: Jun 2007
Location: Strangways, Vic
Posts: 2,208
1/7/11 Through an unexpected gap in the clouds

I'd given up on observing on Friday night, went out to get some firewood before going to bed and behold! the sky was ablaze with stars. Moreover there were distinct dark bits as well - the clearest night I've seen for a long time. So out came the scope. And I got my tape recorder working again.

So I played for a while with some GCs, found a very intriguing PN and enjoyed some open clusters.

Here are the notes. Sorry, the resurrection of the recorder has probably increased the verbiage. Thanks for reading.

Telescope 410mm (16”) f4.9 tri-dob reflector
Eyepieces 28mm UWAN, 17,13,9 mm Naglers, Paracorr
Navigation: Night Sky Observer’s Guide (NSOG), Uranometria Vol 2
Data from SEDS list of galactic GCs and the NGC/IC project

No plan as I was not expecting to see the sky, but galactic centre and GCs beckon.


Seeing good 2/5. Transparency the best I’ve seen for many months. The Pipe nebula is very crisp and dark

NGC 5946 GC in Norma Class IX
15:35:28.52 -50:39:34.8
Vmag9.61 Dia 3.0’

175X Nicely concentrated GC, reasonably bright with obvious core. The halo beyond the core is quite large and soft. Looks about 4’ dia. and the core is about 1’. No stars resolved but the GC has a grainy texture. Good contrast in spite of being in a very busy star field. A foreground star is apparent within the southern edge of the halo.!5946&r=15:35.5&d =-50:40&e=J2000&h=15&w=15&f=GIF&c=non e

NGC 6356 GC in Ophiuchus Class II
17:23:34.93 -17:48:46.
Vmag 8.25 Dia. 10.0

175X A lovely soft glow, quite large and well concentrated with soft core fading into the halo. Very regularly round the outer halo looks about 7’ across, with the core about 2’ with the impression of a sharp point of light at the core. No stars resolved, but quite grainy.

NGC 6333/Messier 9 GC in Ophiuchus Class VIII
17:19:11.26 -18:30:57.
Vmag 7.72 Dia 12.0

175X Not much bigger than nearby NGC 6333, but significantly brighter and much less concentrated. There are 20-30 resolvable stars. It is hard to tell whether the GC is irregular or if the irregular appearance is due to the plethora of objects around it. No distinct core. There is a wide splash of luminance off the northern edge. Looks about 8’ across.

NGC 6342 GC in Ophiuchus Class IV
17:21:10.08 -19:35:14.
Vmag 9.66 Dia. 4.4

175X This GC sits on the edge of dark nebula Barnard 259. A small glow in the night sky with quite a marked core amongst many background stars. No stars resolved, mostly quite regular looks about 4’ across.!6342&r=17:21.2&d =-19:35&e=J2000&h=15&w=15&f=GIF&c=non e

NGC 6440 GC in Sagittarius Class V
17:48:52.70 -20:21:36.
Vmag 9.20 Dia. 4.4

175X Looks very similar to nearby 6342. Quite concentrated distinct soft glow in the midst of a line of f/ground stars. A marked core fading gently to a soft halo. No stars resolved.

NGC 6445 PN in Sagittarius Class 3b(3)
17h 49m 15.0s -20º 00' 34"
Vmag. 11 2.8’x 0.9’

250X This is quite a large PN and it’s hard to tell at first whether it is a ring or two parallel lines. As I keep observing it appears more like a thick-walled, box-shaped ring, but the ring is fainter on the western edge as well as somewhat fainter on the eastern edge. The ring appears to have tiny bright knots so that it looks a bit sparkly. No central star is seen. Brightens with UHC filter, which confirms that it is a ring. Moreover there is a tongue of fainter light protruding from the western soft edge of the ring which looks even more sparky. There also appears to be a soft central glow, surrounded by a dark annulus within the outer bright ring. OIII confirms the above obs, the inner section brightening further and the sparkles in the ring intensifying. The western edge looks quite disrupted.!6445&r=17:49.2&d =-20:01&e=J2000&h=15&w=15&f=GIF&c=non e

NGC 6494/Messier 23 OC in Sagittarius Class II 2 r
17h 57m 04.7s -18º 59' 07"
Vmag 5.5 Dia 30’

90X A splendid OC looks about 30’x50’. Most members look similar magnitude and similar colour. A delicate line of stars trails to the north towards a bright star which I suspect is not a member of the OC. Behind it all is the mottled glow of countless disc stars.

NGC 6531/Messier 21 OC in Sagittarius Class I 3 r
18h 04m 13.4s -22º 29' 24"
Vmag 5.9 Dia 15’

135X This is a stunning cluster next to the Trifid nebula with an intriguing asterism which looks like an angular P-shape (E-W) joined to an elegant loop off about 10 stars to the north. This asterism looks about 6’x6’. There is some variety in the magnitude of the stars, but not much variation in colour. It stands out quite well in the field.!6531!=!M21&r=18: 04.6&d=-22:30&e=J2000&h=15.6&w=15.6&f=GIF&c =none

Bands of thin high cloud start to move in - I watch the Pipe nebula go from stunning to rubbish and so the session endeth.
Reply With Quote