Saturn Nebula and M76

[hgjevans]

This post is not so much an observing report, as an account of tracking down and locating (or not) some tricky (for me at any rate) DSOs. So if that process doesn't interest you, now's the time to skip to the end/the next thread, as appropriate.  

In recent weeks I have been particularly hoping to observe the Saturn Nebula (NGC 7009) and the Little Dumbbell (M76), amongst others. But for various reasons (lack of properly clear skies, in the main) I've only had the scope out once since the middle of summer. Plenty of great sessions with the binoculars, but not much scope-time. Anyway, yesterday it looked as though at last both weather and moon would allow me a chance.

My (quite short) list of targets was just,

• NGC 7009, and, whilst in the area, M72 and M73
• M76
• Any other 'targets of opportunity'

With the scope set up and aligned at about 9pm, I got started. As it turned out the skies were basically clear but quite hazy - that really didn't bode well for things like M76, which, I had gathered from my prep work, can be a tricky one, as Messiers go. And it really didn't help that yesterday was carnival day here, and the whole event was rounded off with a big firework display at around 9:30-10pm down at the riverside - about half a mile as the crow flies, or rather as the smoke drifts (and it did).

I often have difficulty locating faint objects that I haven't viewed before, because I'm never quite sure how they're going to appear *if* I actually do manage to get the scope on them. The result is that I sometimes  just don't recognize them when I see them. And it doesn't help if they're low in the south, where my general knowledge of the constellations is poor anyway. On this occasion I had planned to find the Saturn Nebula quite easily (I thought) by first finding M72 and 73, which are on near enough the same declination as alpha Capricorni. Alpha1 and alpha2 Cap, together with nu Cap, and beta Cap below are quite unmistakeable and easy to locate, and then it would just be a short traverse in right ascension to M72.

Well, sure enough alpha Cap was a straightforward starting point, but I then had to wait a while for my my real targets to clear a roof-line. I busied myself with the binoculars, enjoying M13, failing to pick up M5 (already behind the trees, I reckoned), plus a few other odds and ends, all the while noticing that the sky really wasn't remotely as clear as the full column of zeros on Clear Outside had led me to hope. With the naked eye I could see Pherkad (mag 3) in Usra Minor, but nothing beyond that, and just a couple of stars inside the great square of Pegasus, and then only with averted vision. It wasn't encouraging.

Still, we have to work with whatever opportunities we get, so I pressed on. By the time my targets, according to my  reckoning, had cleared the roof, the worst of the smoke had also passed. So, back to alpha Cap. From there it should have been about 35 minutes of right ascension or thereabouts back to M72, and just a few more minutes to M73. Well, that was the plan. Nothing I saw was identifiable as a globular cluster. I did think that I *might* have found M73, but searching with a low power eyepiece I really couldn't be sure, and I hadn't done my rough calculations to allow for needing higher power just to pick the clusters out. I tried a higher power, and groped around a bit, tweaking the declination in what I thought was the right area, but to no avail. I think probably the sky conditions were just too poor.

Unfortunately, I was relying on first finding M72, then M73, and then a short hop to the Saturn Nebula. So essentially I hadn't even made it to first base. An improvised 'plan B' was neeeded. I've been using the SkEye app on my phone recently, though until now it has really only augmented my observing, checking whether this or that object was above the horizon yet, or identifying some constellation I didn't recognize - I hadn't really used it in anger to actually help track something down. I wasn't even sure I could do that, just ad hoc, without any planning - the 4 inch screen on my phone is limited, to say the least. It turned out it was just good enough. SkyEye showed the little triangle of epsilon, mu. and 7 Aquarii (easy in the finderscope), with its eastern arm pointing the way down to nu Aqr. From there it was a small tweak of RA to the nebula. And there it was - a small blue-green ball, revealing its elongated shape in averted vision. It was obvious that a bit more aperture and a darker sky would have helped, but as a first viewing it was very satisfying.

After that, M76 was a doddle. 51 Andromedae and phi Persei were my reference points, *just* about visible to the naked eye in what were now really very hazy skies, but easy to pick up in binoculars or the finderscope. From phi Per it was less than 1 degree's hop to the mag 6.7 star that sits just a few arcminutes away from the Little Dumbbell. And I was delighted to find that it showed up easily at every power I tried. In higher powers there was clearly something of a bow-tie shape to it - I know I was only getting the brightest central region of the nebula and not the more diffuse outer lobes, but once again they could wait for a time with more aperture and/or a darker sky.

[xtreemchaos]

great report and imfo Huw,nice read.thanks for sharing  charl

[hgjevans]

Thank you Charl - I'm glad you enjoyed it. Much better conditions this evening - at least until about 11pm, when it completely clouded over in about ten minutes. Anyway, with a little more care, this time I managed to find both M72 and M73. And given how faint they were, even in reasonably good skies, I'd say it was definitely the haze (maybe not helped by the fireworks) which scuppered my efforts on Saturday. M72 was really just a smudge, and I couldn't resolve any individual stars. M73 was more defined, with four stars clear in direct vision and at least two more in averted.

Emboldened with a feeling of invincibility I thought I'd have a crack at M74 - that brought me right back down to earth with a bump. Not a ghost of a chance! I consoled myself with a look at M34, and I was starting to line things up for M52 and a  few NGC clusters in Cassiopeia when the clouds rolled in. They'll have to wait for another day.