After a stormy and unpromising day, Friday night cleared nicely. I was out all evening, not getting home until past 11pm although, given the light nights at this time of year, that’s not really a problem. However, I didn’t feel like getting the 12″ out – and the weather forecast indicated that clouds were soon going to roll in, continuing May’s unsettled note (May’s weather quite often is rubbish but I hope this isn’t the start of yet another lousy summer) so instead I brought out the little 70mm refractor, recently released from its dark prison in the depths of a cupboard. It’s imprisonment wasn’t intentional, it’s just that I don’t have a lot of use for such a small scope. Or I didn’t think I had, until I decided I want a travel scope just in case I am able to go anywhere next year. Unfortunately air travel restrictions don’t allow you to take anything much larger than a small refractor or Mak-Cass overseas. People better at woodwork and metalwork than I am have made collapsible 8″ or larger dobs for airline travel, but that’s beyond my limited practical capabilities.
Anyway, with the lack of anything else to write about on here, here’s a short account (I won’t say ‘report’ like a lot of people do on astronomy forums; I don’t like the term when used for descriptions of observing sessions as I think it’s too formal, making it sound compulsory and too much like work) of the Friday night mini-session with the Vixen.
Date: 27th May 2011
Conditions: Cloudless, no dew, chilly, breezy.
Equipment: 70mm (2.8″) f/6 Vixen refractor with Televue 25mm (16.8x) and 11mm (38x) Plossl eyepieces. Lumicon 2″ UHC filter.
The summer Milky Way was rising, and Cygnus was beginning to clear the nearby trees, so I aimed the little scope at the various star fields. The beauty of a small rich-field scope is that you don’t need a finder to aim it. Because of the wide field views, it’s easy to find what you’re looking for just by sighting along the tube, something which is all but impossible with a larger, longer focal length instrument.
As well as looking round the rich Milky Way of Cygnus, I looked for individual objects, bright Messiers generally. M29, a coarse and poor open cluster in Cygnus, was easily seen at 16.8x. Despite its sparseness it was an attractive sight at 38x, standing out nicely from the Milky Way. It’s seven brightest stars were all easily seen in the tiny scope.
In Lyra, M57 was easily seen at 16.8x as a non-stellar object in a rich area. Putting up the magnification to 38x showed an oval with a darker middle.
Turning to Hercules, M13 was easily seen in the scope, and was resolved, despite being at a neck-twisting angle. No surprise there, as it’s a naked eye object on a good night. It wasn’t quite naked eye the other night, though, as the sky wasn’t quite dark enough for that. I didn’t bother with M92, because of the awkwardness of the eyepiece angle – one of the areas where a reflector beats a refractor hands down.
M81 and M82 in Ursa Major provided a lovely view at 38x. M81 was oval, with a slight hint of spiral arms while M82 was a bit brighter and showed mottling.
Scorpius was rising so I decided to see what M4 looked like with the 70mm. Despite its low altitude, the view was surprisingly good and the cluster began to resolve at 38x. If it was higher, it wouldn’t be bad at all with the tiny scope.
Meanwhile, Vulpecula had cleared the trees, so I looked for and easily found M27, the Dumbell Nebula, at 16.8x, as a round patch in a rich area. I was expecting to just see M27’s ‘apple core’ shape but, somewhat surprisingly, at 38x, the fainter lobes showed up well.
Back to Cygnus and NGC 7000 and IC 5070/5067, the North America and Pelican Nebulae. NGC 7000 is a pretty easy naked eye object as a shining patch adjacent to Deneb, as by now, it was 0040 and dark enough to see fainter objects. The shape was easy to make out with the help of my Lumicon 2″ UHC filter held to my eye, with the dark ‘Gulf of Mexico’ prominent. IC 5070/5067 was fainter and needed averted vision to see properly. It’s a nice sight through my 8×42 binoculars though.
It was getting cold and it was nearly 1am, so I packed up – which was the work of less than a few seconds, another plus factor of a small scope. Unfortunately small scopes don’t cut it when you want to view faint deep sky objects and, with a rich field scope such as the 70mm, you can’t get enough magnification for detailed views of DSOs or the planets. However, for a ‘grab and go’ scope and a travel scope, it’s ideal. One scope can’t do it all; my 12″ is way too large and cumbersome to be much use as a ‘grab and go scope’ (being a one-piece tube it barely fits in my car) and doesn’t give wide field views. As noted Arizona observer Steve Coe once said, ‘There’s no such thing as an all-purpose telescope’.
The Texas Star Party begins today. Hopefully they’ll have good clear skies. I wish I was there.