globulars etc - Observations 3-4/6/10

[Paddy (Patrick)]

Dear all,

Here are some notes from observations last week. The plan was to follow up some of Les' suggestions on Ara and to visit some of the globulars in the thread on June observing challenge. Two very pleasant evenings of play near the galactic centre.

Thanks for reading. And thanks to those who put forward suggestions for targets.

Telescope 400mm f4.9 tri-dob reflector
Eyepieces 28mm UWAN, 17,13,9 mm Naglers, Paracorr
Guiding: Night Sky Observer’s Guide (NSOG)

3/6/2010

Seeing good 2/5

Transparency – excellent 7/7

2100

ESO 138-29 + 30 Interacting Galaxies in Ara "toadstool galaxies"
175X Fairly faint against the background of the Milky Way disc. The main galaxy is quite distinct with obvious central core in circular surrounding haze. Dark areas between the surrounding haze and the core can be seen which suggest spiral arms. It is at the base of a thin triangle of stars - to the southeast of the apex of this triangle, the haze of the second galaxy can be seen. Both galaxies more obvious at 250X. the impression of a dark ring around the core of the main galaxy is more obvious, the second galaxy remains a haze with no obvious detail. I can’t say that I can see the bridge that connects the two.

NGC 6300 GX in Ara
175X again many milky way stars around. Significantly larger than ESO 138-29. Some foreground stars over the galaxy, which is an oval shaped haze 5x7’ with bright centre with some dark pools suggestive of spaces between spiral arms. Looks like a partly edge-on spiral. The overlying stars make it hard to tell if there is a bar. 250X improves the detail, confirming the presence of the darker areas between spiral arms.

NGC 6362 GC in Ara
175X Moderately concentrated GC with W-E belt of resolvable stars across the cluster. There is a spattering of other resolvable stars and a background haze which has small arms to the west and east, a slightly bifid one to the south and a more dispersed one to the north, giving the impression of a slightly disrupted egg shape to the cluster. The northern arm has fewer resolvable stars than the others. 250X the cluster looks less organised and more irregular with more projections and dark patches on the periphery.

NGC 6397 GC in Ara
135X Brighter and more concentrated than 6362 with more resolvable stars some forming a ring around the cluster, the center of which is a tight packet of haze. Swirls of resolvable stars adorn this lovely cluster. The edge of the cluster is hard to pick against the background of galactic disc stars.175X enhances the contrast of the cluster against the disc stars. Dark patches in lobes around the central core of the cluster. I estimate the dia 10’. 250X Enhances the patchy darkness around the core of the GC.

IC 4651 OC in Ara
135X Wide cluster with little variation in colour of its constituent stars. Several dark lanes curve through the OC, one is a deep U-shape and atop it is a gentler counter curve – the two forming an acorn shape. This OC was a very obvious bright haze in the finderscope, so I’m surprised it didn’t get an NGC number.

NGC 6326 PN in Ara
175X Small distinct blue-green disc, perhaps slightly oval shaped with long axis SW-NE. Quite small with no internal detail apparent. 250X shows no further internal detail. The PN is very near two stars and has the appearance of being part of a larger bubble to the east, between these 2 stars. Brightens considerably with OIII filter which increases impression of the bubble to the east of the disc.

4/6/2010

2130

M4 GC in Scorpius
175X Quite concentrated haze with many resolvable stars. I note an asterism in these stars resembling a flower pot with its base pointing west and a small tongue to the east. There is quite a spray of other stars in front of the concentrated but slightly irregular haze. Looks about 14’ across, with the bulk of the haze spanning 7’

NGC 6453 GC in Scorpius
175X Small irregular circle of haze with a few stars, which I suspect may be foreground as the GC itself seems quite small and distant. A distinct central core of brightness surrounded by fainter halo with some bright patches to the north and east. 250X More detail obvious at this magnification. Bright core is more distinct and projections to north and east are clearer. Appears to span 3-4’.
NGC 6426 GC in Ophiuchus 175X Situated between gamma and Beta Oph, quite faint, appears about 5’ across. Slight concentration, with a bright patch to the south of the GC’s centre. 250X reinforces the impression of the bright patch to the south of the centre of the cluster. Hints of a few resolved stars.

NGC 6235 GC in Ophiuchus
175X Significantly brighter than 6426. Appears quite compact, about 3-4’ diameter with distinct core which appears to have a V shape with the apex towards the east. The unresolved haze is more elongated to the east than the west. Some resolvable stars in the v-shaped core. 250X The resolvable stars are clearer at this mag. as is the v shaped core.

NGC 6304 GC in Ophiuchus
175X Compact, concentrated and bright with distinct core, granular texture and some resolvable stars. I estimate 4’ dia. 250X appears more textured, but not a lot more structure apparent although there does seem to be a slightly darker band around the northern edge of the GC, but with haze brightening beyond this band.

NGC 6316 GC in Ophiuchus
175X Roughly the same size as 6304, slightly more compact and concentrated. Reminiscent of a modest 47 Tuc in that it has a very marked core. No resolvable stars. Very regular compared to the other GCs of this session so far.

M69 GC in Sagittarius 175X Quite bright, concentrated and regular GC with gradual concentration towards the core. A few resolvable stars around the periphery. No strands of distracted stars.

M70 GC in Sagittarius
175X Also quite concentrated with distinct punctum in the centre with darker annulus around this, then brightening again towards the edge. Some resolvable stars at the edge and at the core. Thin strands of stars and haze to the north and west, but otherwise fairly regular and intact.

M22 GC in Sagittarius
175X Stunning – one of those GCs that are beyond words. Bright enough to withstand the rising moon, many resolvable stars and strong haze, somewhat concentrated by not with a distinct core. And its adornment of the darker chevron across the centre and pointing north, which is a local dearth of resolvable stars. Many shapes traced out b resolved stars and in the grainy texture of the haze, even faint stars can be discerned.

A lovely way to end a good night!

[mental4astro (Alexander)]

Paddy, beautiful descriptions mate. Thank you. I've really enjoyed reading your report.

[Rob_K]

Great report Patrick, a nice range of globular clusters there!

Cheers -

[Paddy (Patrick)]

Thanks gentlemen!

[MikeyB (Michael)]

Your observing notes make great reading, Patrick - you've got a real flair for them. Tonight I'll be retracing your footsteps, with your notes alongside me for guidance - thank you for sharing them with us.

[Paddy (Patrick)]

Thanks, Michael for your encouraging response. Hope you have a good night.