Cygnus and Hercules Pt2

[Paul81]

Nice clear skies last night so decided to carry on with the observation of Cygnus and Hercules. All images below are using the AA 6" RC at F4.5, Astronomik CLS filter (visual), SX Lodestar and Lodestar Live V0.10. I still need to work on the collimation of this scope, I am looking to setup a ball-bearing artificial star to help in the process. Also I found focus slipped a little last night - I didn't notice until later and adjusted the focuser tension. Ah well, I still had fun and enjoyed myself so who cares if a few of the stars are fuzzy?!

Also for the first time my observing session was not cut short by clouds - but rather by the fact that both of my laptops batteries were pretty drained (on the red). I managed to get the objects in Cygnus with my old macbook at which point it died, and then I switched to my new one and I got some time before it also died. I'll defiantly be making sure they are charged in the future!   Sadly, in order to preserve batteries, I couldn't do my normal observing where I examine the object using different black / white levels etc and make notes as I kept the laptop display off for a few minutes, had a peek at the latest result and so on.

All images posted here are direct exports from LL as observed during the session - no post processing has been applied.

The first object was IC5146 The Cocoon Nebula. Despite reading that it is a 'bright' nebula in Cygnus, I found this was invisible unless I used > 10s exposures. I think sum mode here really helped bring out some detail, and as a comparison I did the same 8x30s run in median mode too:

The Cocoon really does remind me of M20, it has the same kind of intricate dust lanes. The nebula which is a mix of emission and reflection (like M20) is about 4,000 LY away. 

Having observed the Fireworks galaxy last time out, I switched over to NGC7013, and tiny galaxy located just under the east wing of the swan. I plan to return to this one using the VX10 at some point for a higher resolution look (the AA6RC with the focal reducer is about 2.43 arc sec / pixel - the VX10 at the same focal ratio is about 1 acsec / pixel). The galaxy is quite distant, about 41M LY and is quite small, some 48,000 LY across.

Staying within the Summer Triangle it was over to some Globular clusters. First up M71 in Sagitta. This is quite a 'loose' globular, and for a long time astronomers though it to be a tightly packed open cluster. The cluster is about 12,000 LY away. I switched to 20s exposures to avoid saturation which I have suffered from before with longer exposures on globs.

Moving to Hercules, no globular cluster session could be complete without the mighty M92 and M13. M92 is about 27,000 LY away and is thought to be one of the older globular clusters of the Milky Way. I think people tend to overlook M92 as it is so close to M13, which is prettier but M92 still has a big charm in my book.

And finally M13, which is about 25,000 LY away and most people agree is the best globular in the northern hemisphere - I certainly can't argue against that! I wasn't really into globular clusters until the day I first saw M13, it certainly changed that and was a wow moment.

Median stacking really controls the noise with images of globular clusters, and I found more than 6 exposures was diminishing returns in terms of bringing out extra detail - better to observe more fascinating objects! 

[RobertI]

Really nice results.

[Martin Meredith]

Great shots, Paul. I really like the Cocoon -- it also looks a bit like the Owl, albeit with sadder eyes...

The looser globs are coming out well. I look forward to the day when the propellor in M13 can be captured with brief exposures.

What tools are you using to collimate at f4.5?

Martin

[Paul81]

I see what you mean about the Owl and sadder eyes! I've never seen it that way before, but now you mention it! Haha!

I use a combination of Howie Glatter laser tools and a cheshire. When I got the scope I collimated it to what I thought was right, and when I tried it under the stars it was wrong - I adjusted the secondary a little and that made a huge difference but I still think its not 100%. I think it is my misunderstanding of what things should look like in the cheshire - the laser is pretty straight forward (well it seems so..). I now have got some ball bearings so I am going to try to make an artificial star. I want to go over the whole lot again and get it solid in my head - I am sure it is me just being an idiot somewhere in the process. Running with the 0.5x reducer makes everything more sensitive, but it is worth it as the scope itself is fantastic - really light, portable and solid as a rock - and a nice FL for a lot of targets. The scope seems well built enough that once collimation is right I think it will hold it very well.

I am going to get a focus mask too to help in that department, again with the reducer the sweet spot is really tiny. I think the stock focuser on the RC is up to it - its just the cheap one but the lodestar is so light it doesn't matter.