Keyhole Nebula using 20 inch RCOS

[batema]

Hi,

What an amazing night I have had and I thought I would share the results of my first ever experience using this scope.

Firstly its not mine but we have made friends with a colleague who has one and spent the early evening doing some remote telescope work. The purpose is not to show any expertise on my behalf which is sadly lacking but to show the first efforts of this telescope and the amazing field of view it pulls.

The image is 16 x 3 Minute shots through a Hydrogen Alpha 4-5nM filter. It is not guided but I believe is on a paramount mount. No darks or anything and I think the camera is a SBIG 11000 mono. What an amazing piece of technology. The first image is about 50kb so you can see the field of view and the second about 180kb.

If you can offer advice on focus or anything that can help with this scope feel free.

Mark

[duncan]

Hi Mark,
WOW!!! WOW!!! WOW!!!!
Mate my monitor just isn't big enough to do this image Justice!!!!
Super amount of Detail, but it is thru a 20" RCOS.
Super image, so how about one in colour?
Cheers,
Duncan:thumbsup:

[rat156]

Hi Mark,

The image looks a little soft for something taken through such a big scope.

I've attached a similar region taken through my 8" RC, the 20" should blow this away.

It's either focus or it's seeing, one of these you can do something about. Pick a reasonably bright star and spend ten to twenty minutes ensuring that you have indeed got focus, then move to the field, take a short exposure and check all the stars across the field for focus issues. Remember that the RC has a curved field, so some compromise will probably be made. Usually the seeing at my place makes this a mute point.

Cheers
Stuart

[RobF]

Also for reference, have attached a crop of a Ha stack (19x5mins) from my 8" Skywatcher from the backyard in Bris. This has been poorly deconvolved (suspect I could do quite a bit better now in PixInsight), thus the star rings, but again agree you should get much better images once you come to grips with such amazing gear.

Sounds like a heck of a lot of fun Mark!!

[bmitchell82]

Being a 20" RCOS it will have auto focus, if its just been setup has it been collimated? just a question because even in rough seeing, you should have a way clearer image than that... by a long long way with a SBIG 11k + RC the spot sizes for the 20" should be tiny and resolving stars to nice pin points!