Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: RobertM on Apr 10, 2011, 21:31:53

Title: Kelling Heath M81 & M81
Post by: RobertM on Apr 10, 2011, 21:31:53
The first from Kelling, very blusterey conditions for this one so stars not what they should be.

20 x 60s ISO1600 Canon 1000D on C11 Hyperstar/NJP160 unguided.  Stacked, flat fielded and DDP in MaximDL, no other processing.

(http://farm6.static.flickr.com/5144/5606927531_a48331758f_b.jpg)

Full (bin 2x2 size) http://farm6.static.flickr.com/5144/5606927531_faa976d19b_o.jpg (http://farm6.static.flickr.com/5144/5606927531_faa976d19b_o.jpg)

Robert
Title: Re: Kelling Heath M81 & M81
Post by: Fay on Apr 11, 2011, 00:09:29
Well that looks good Robert, it was blowing a gale!!!!!!!(as you know) Did you not want colour?
Title: Re: Kelling Heath M81 & M81
Post by: Rocket Pooch on Apr 11, 2011, 00:10:01
Looks ok, but where's the colour?

Chris
Title: Re: Kelling Heath M81 & M81
Post by: RobertM on Apr 11, 2011, 08:34:03
Whoops, yes I'll fix the colour.
Title: Re: Kelling Heath M81 & M81
Post by: JohnP on Apr 11, 2011, 12:08:13
Well a lot of detail for 60 secs exposure - shame about the conditions though....
Title: Re: Kelling Heath M81 & M81
Post by: Mac on Apr 11, 2011, 15:32:49
Nice capture
Title: Re: Kelling Heath M81 & M81
Post by: Jim on Apr 11, 2011, 17:20:49
That's amazing for 20 mins Robert. I did 4 hrs with my 5" at F7 and did not get as much data as you. What's the speed of the C11?
Title: Re: Kelling Heath M81 & M81
Post by: RobertM on Apr 11, 2011, 17:26:51
Focal ratio is f/2 and focal length 570mm.

Robert
Title: Re: Kelling Heath M81 & M81
Post by: Mac on Apr 11, 2011, 17:47:55
 :o :cheesy:
Title: Re: Kelling Heath M81 & M81
Post by: MarkS on Apr 12, 2011, 08:15:59
Robert,

It's a great shame the wind blighted this.  At F2 with the modded Canon 1000D this could have been a stunning image.

I assume you chose 60sec subs because of the wind?  At F2 I would recommend at least 150sec.  I generally use 300sec at F2.8 but F2 is twice as fast as F2.8    I then combine with shorter exposures (or exposures taken at lower ISO) to deal with the saturated areas because my 350D is only a 12 bit camera.

Mark
Title: Re: Kelling Heath M81 & M81
Post by: RobertM on Apr 12, 2011, 08:42:17
I really wasn't going to post this image but with all the effort of going to Kelling I thought I just had to.

Yes Mark, 60s was because of the conditions.  If you look closely you can see the stars are all flaired in a fan shape on one side due to the wind and as a result a lot of resolution was lost.  I'll post the other image in the next few days once I've had time to process it.

Am still getting used to the kit but am nearly there, the next dark sky opportunity should hopefully see something more representative of what the system can do.

Robert
Title: Re: Kelling Heath M81 & M81
Post by: mickw on Apr 12, 2011, 09:11:02
Well done Robert pretty good considering the conditions