The run of crap weather ended for a brief period over the weekend (but is back to being rubbish today), so I was able to do some observing on Saturday and Sunday night. Saturday night’s session was excellent, but Sunday’s was less so, thanks to some pretty woeful transparency due to some thin high cloud.
I hadn’t used my 18″ since the Isle of Wight Star Party, back in March, so it was nice to get it out of the shed and set it up. The new 2″ Howie Glatter laser collimator worked brilliantly but I will get a TuBlug for use with it, otherwise I have to look in the top of the scope to see the laser and the shadow, then go to the back of the scope to make the necessary adjustments. The collimation was only slightly out, which wasn’t bad, considering the telescope had been disassembled after the star party, driven over shoddily-maintained roads which resemble Afghan goat tracks (at the risk of insulting Afghan goat tracks), carried up the garden and reassembled.
As well as the H2500 I have been doing the AL’s Globular Cluster program. As well as observing 26 of these at TSP last month, I was going to use some ‘ancient’ observations from my 1997 Australia trip but I decided against this, apart from NGC 5139 (Omega Centauri) and NGC 104 (47 Tucanae) which I will keep in the list, as I have enough observations from recent years (2010 to now) I can use, including some from this weekend. You need 50 observations to complete the program, I now have about 70-odd so I’ll select my best ones to send in, including the Challenge Object (I have Palomar 11, NGC 5466 and 5053 to choose from). One of the good things about these programs is the fact that doing them often takes care of objects on the Herschel lists, as well.
I have loads of observations to type up, from the Isle of Wight Star Party, the Texas Star Party and the past two nights but I’ll save these for the next rainy day – and I don’t think I’ll have long to wait, as the unsettled period goes on.
Galaxy groups and clusters are also among my favourite targets, mainly because find one and you have found half a dozen or more, so I put Abell 1656, the Coma Galaxy Cluster, on my list.
Date: 12th May 2012
Conditions: Clear, very dewy, no Moon (rises at 0200)
Transparency: II-III; Seeing: II; NE Limiting Mag: 6.0
Equipment: 18″ f/4.3 Dob with 22mm TeleVue Panoptic (90x), 15mm TeleVue Plossl (132x), 12mm TeleVue Nagler (165x) and 9mm TeleVue Nagler (219x).
I began with some eye candy (M53), then went on to some fainter stuff before returning to bright objects. Objects observed were M53, a globular cluster in Coma Berenices, NGC 4147, a globular also in Coma B, an attempted observation of NGC 5053 in Coma B, Abell 1656, the Coma Galaxy Cluster, M5, M56 and M3. The Messiers were objects that I hadn’t looked at in about 17 years so it was nice to catch up with them again, besides I wanted them for my Globular Cluster observing progam mentioned above.
I failed to find NGC 5053, a notoriously hard object to observe because of its low surface brightness (I returned to it on Sunday night with more success).
I identified 14 members of Abell 1656 during the course of an hour and a half, plus I saw many others that’ll have to remain nameless until a better night, as the transparency, while ok, wasn’t as good as it could be. The ones I could put names to were NGC 4889, NGC 4874, NGC 4864, NGC 4869, NGC 4865, NGC 4881, NGC 4860, NGC 4848, NGC 4921, NGC 4911, NGC 4923, NGC 4908, IC 4051 and MGC+5-31-46, the latter object only visible with averted vision. I used my new (second-hand) Naglers on these and was pleased with their performance.
I finished with some more Messier globulars, M5, M56 and M3, before packing up.
Date: 13th May 2012
Conditions: Cool, slight dew, breezy.
Transparency: II-III; Seeing: II, NE Limiting Mag: 5.8 to 6.0 later before deteriorating badly.
Equipment: 18″ f/4.3 Dob with 22mm TeleVue Panoptic (90x), 15mm TeleVue Plossl (132x)
The sky was not that good although the transparency did improve slightly later. I ended up just observing three objects, all globular clusters, NGC 6229 in Hercules (another re-visit to something I’d not seen in years), M92 (the last time I looked at this was in 1999) and I had another crack at NGC 5053, this time successfully, despite the less-than-optimal sky conditions. NGC 5053 was faint, very faint and amounted to nothing more than a roundish glow with stellarings in moments of good seeing and no central condensation whatsoever. As globular clusters go, it is a pretty poor specimen!
I decided to go after some more galaxy clusters but the transparency gave out completely and the sky became extremely milky. When it’s like that, it’s no good for anything, much less faint galaxies which vanish if even the slightest bit of haze appears.
So, it was a couple of good sessions – well, one excellent session and one not-so-hot one. It’s been a mediocre year so far for observing, with not many sessions because ‘life’ has just plain got in the way, although it had been quite clear up until the second week of April when the period of bad weather set in. I’ve done most of my observing at the IoW and Texas SPs.