Some more tips on DSO observing

[209herschel]

Hi everyone,

I've had my 10" GSO dob for a while now and I've learned quite a bit. I've added a setting circle and I use a Wixey and I feel this is working well. I've never had it outside of my inner city Sydney backyard, though I'll get a chance over the summer. I really want to get better with deep sky objects before then and I can't help but feel I could get more out of the scope on DSOS. So that's the advice I'm after.

I have a 9mm, 15mm, 25mm and 32mm plossls and a 32mm Super - all GSO. These came with the scope.

I've made a list of objects to move through, starting with Globular Clusters, then Open Clusters and finally Galaxies.

I think light pollution is a major issue where I am. For example, I don't think I've ever seen a galaxy. Should I be able to? Will light pollution affect these DSOs very badly? I've seen the Lagoon and Trifid Nebula but they're very feint.

I'm keen for any advice on how to get more out of my deep sky observing. For example, on 47 Tuc, I see the cluster but it's not very bright and it's supposed to be the best one in the southern hemisphere. Could this be because it's quite bright in the yard, regardless of the time? I only realised recently that I needed more magnification than the 32mm on globular clusters and this made a big difference. It's these kinds of things I'm still picking up hence the request for advice so I can fast track my learning!

I'm looking to pick up a 24mm eyepiece of higher quality for the summer. Will something like the ES 24mm 68 degree be a measurable improvement over the 25mm GSO plossl? And then would a 24mm Panoptic be a measurable improvement again over the ES?

On finding DSOs, I use the setting circle and wixey. But I've recently started measurable the TFOV for each of my eps and then trying to learn to star hop to objects. I sometimes wonder whether I'm looking at the DSO I think I am! This is especially the case with something like 47 Tuc where there are a couple of other clusters nearby and I've never certain I'm looking at the right cluster. Do most of you star hop by knowing the FOV of the ep and using an app like Sky Safari or Stellarium to move around? I just thought I'd try something in addition to the setting circle/Wixey.

Thanks again for any advice. I've learned a million things from you guys already.

Herschel.

[barx1963]

Hi Herschel
Well done on getting to use the 10" even in Sydney.
Light pollution will be your main issue. The problem with light pollution is that it is mainly the glow of the city itself causing the sky to brighten rather than any lights near you, so even if you manage to reduce the lights in your backyard, ou will still have an issue. Having said that, the darker your observing area, the easier it is to get dark adapted to maximise your chances of getting those faint fuzzies!
47 Tuc will be the brightest object anywhere nearby, there is another nice glob near there (NGC362) but it is nothing like 47Tuc! 47T is so bright it is a naked eye object in my backyard here in Colac.
Galaxies will always be the hardest things to get in a light polluted environment as they are very faint and have a low surface brightness most of the time. that said have a try for NGC 253 which will be nearly perfectly placed ATM.
With eyepieces, the 24Pan is a beautiful EP. I had one for many years and only gave it up when I upgraded to Ethos. I have only had a few glances through ES eyepieces so cannot comment on them.

Malcolm

[Allan]

Once you get use to observing from a dark site, then observing DSO from the city becomes decidedly depressing. I barely spend any time observing galaxies from my backyard, that's not to say they are hard to find as there are still a huge number to see even in your 10", it's just that they don't reveal much detail because of all the sky glow. Stick with the bright ones like NGC 253 that Malcolm suggested to start with and go from there. Or else drive to a dark site and go nuts observing galaxies everywhere.

Both the 24mm eyepieces you mention will be a nice improvement over the plossl you are using. They will be good for general widefield DSO, but something around a 2mm exit pupil or 10mm I think in your dob, will be much more suitable for observing galaxies. There's an old saying I like to repeat, and that is spend the most money on an eyepiece focal length that is double the f/ratio of your telescope. That works for me as I find I spend most of my time using my 10mm and 13mm eyepieces observing DSO's.

I use Sky Safari to find objects and also control my dob. You can set it up to display the exact FOV for the eyepiece you are using. That way when you are trying to identify an object, you just compare what you see in the eyepiece with the display on Sky Safari.

Some more tips for observing DSO's. Drive to a dark site. Use a seat. Use a hood and/or eye patch. Use a dim red torch and protect your night vision. Use averted vision when looking at targets. Don't drink alcohol or caffeine(I think) because it mucks with your night vision. Don't hold your breathe because the loss of oxygen mucks with your night vision to. Try observing targets when they are at least 30 degrees above the horizon. When observing faint targets, give the telescope a tap every now and then as the movement will help your eye detect detail. Buy a narrow band filter for observing nebula. Drive to a dark site.

[N1]

I currently own 2 ES eyepieces (16 and 28mm), as well as a 24 Pan. Going by the physical and optical quality of the 2 ES units using the TV as a bench mark, I have no reason to believe that the 24mm version of the ES 68° will be anything other than a great eyepiece.

Increasing the power on DSOs can help reduce the effects of LP somewhat by making the background sky darker. But there is no substitute for a dark site. Having said that, the more prominent DSOs are still worthwhile targets even from suburban skies, IMHO.

[209herschel]

Thanks very much for the advice Malcolm. I also think more time with the scope will make me better at finding things more easily. I'm going to concentrate on 47 Tuc on the next few tries and I'll also aim for the Sculptor Galaxy. Cheers.

[209herschel]

I'm happy to hear that. It's really a matter of the 68 24mm ES or the Panoptic which costs so much more. From Allan's comment below, I'm going to try higher magnification on DSOs. I think it may be I've been using too low a magnification. Anyway, I'll just keep experimenting. Thanks very much.

[209herschel]

Yes, I really can't wait to try a dark site. Until then I'm going to do the best I can in the yard. It's also annoying that the back fence is about 30" up so it limits things a bit! Thanks.

[byronpaul]

Hi Herschel,

good to see the setting circles and Wixey are working well for you.

Aside from what the others have said, how is your collimation?

Light pollution certainly hampers DSO observing in city areas, but more time I spend at my scope the more passion I'm developing for open clusters ..... and these should be easy to find from your back yard. But your collimation needs to be pretty good else it will look like your seeing seagulls or eggs.

No sure what tool you are using to find targets? Stellarium is very good but on a mobile device it is small and a laptop is usually either too big to have at your scope or too bright and effects you sight dark adaption. On the other hand if you do have an iPad or Tablet I can't recommend SkySafari highly enough. The $18 version is all you would need and it's amazing what is included for that small fee.

Paul

[N1]

Here's a good read:

http://www.cloudynights.com/page/articles/cat/user-reviews/24-26-mm-eyepiece-comparison-r2651