Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Whitters on Sep 13, 2009, 19:01:35

Title: NGC7000 and area
Post by: Whitters on Sep 13, 2009, 19:01:35
Tamron 105mm f2.5, Astronomik Ha, 13th September 2009. Each section 80 minutes 12*400 sec unguided.
(http://82.69.92.28/Astronomy/Images/MX916/2009_09_12/NGC7000Final.png)
Title: Re: NGC7000 and area
Post by: MarkS on Sep 14, 2009, 05:46:23

You've got some nice detail there Paul - it's a good scale.  I can only just make out the mosaic joins.

At F2.5 I'm surprised not to see lots of coma but I suppose you have a very small sensor which uses the centre of the FOV - which camera was it?

Mark
Title: Re: NGC7000 and area
Post by: Whitters on Sep 14, 2009, 08:42:21
Thanks Mark, I forgot to trim the edges of the images before the final stitch, which may be why the joins are more obvious, Can you feather these edges, would that help?

The camera was the Starlight Xpress MX916.
Title: Re: NGC7000 and area
Post by: Whitters on Sep 14, 2009, 08:44:14
Just noticed that the stars on the bottom image look a little wierd, I'll have to take another look at that too.
Title: Re: NGC7000 and area
Post by: RobertM on Sep 14, 2009, 10:10:34
That looks realy excellent Paul, I really love these widefields.  Had the same idea myself but that didn't turn out too good without any filter.  Any plans to go deeper on this one and perhaps add some OIII or SII data?  You could possibly stop the lens down to improve sharpness a little and that would ease putting the mosaic together.

Robert
Title: Re: NGC7000 and area
Post by: Whitters on Sep 14, 2009, 13:02:15
Hi Robert, Thanks for the suggestion of stopping the lens down. I'll give a that a go, maybe try at f4.
It's been years since I did any wide angle imaging, before I had the Losmandy, I'll have a go with guiding too so I can get longer subs.
Definately want to go with other wavelenghts. I guess watch this space ;-)
Title: Re: NGC7000 and area
Post by: Fay on Sep 14, 2009, 13:06:42
That's nice Paul, unguided!! Gone together well
Title: Re: NGC7000 and area
Post by: Whitters on Sep 14, 2009, 13:08:16
As a comparrison  :oops:, an image of the same area using the same imaging kit back in 2003. using 30 X 30 second exposures (http://82.69.92.28/Astronomy/Images/MX916/August_03_2003/NGC7000_Ha-copy-6.png)
Title: Re: NGC7000 and area
Post by: Rocket Pooch on Sep 14, 2009, 13:18:50
big FOV  :o
Title: Re: NGC7000 and area
Post by: Mac on Sep 14, 2009, 14:57:20
very nice mosiac,
nice to see the comparison and the progress thats been made.

Mac
Title: Re: NGC7000 and area
Post by: Whitters on Sep 14, 2009, 21:24:32
The strange black blobs around the stars are artifacts introduced by the rotation tool wthin Photoshop. Any ideas on how to fix 'em?
Title: Re: NGC7000 and area
Post by: Fay on Sep 14, 2009, 21:29:00
Sorry Paul. That is a hard tool to use, could you do it in Maxim?
Title: Re: NGC7000 and area
Post by: RobertM on Sep 14, 2009, 21:59:12
Of you have MaximDL try the Mosaic stitch tool, it's magic...
Title: Re: NGC7000 and area
Post by: Whitters on Sep 14, 2009, 23:13:43
Fay,You are a marvel :-)
Merge in Maxim, curves and levels in Photoshop

(http://82.69.92.28/Astronomy/images/MX916/2009_09_12/NGC7000Maxim2.png)
Title: Re: NGC7000 and area
Post by: Whitters on Sep 14, 2009, 23:15:33
Robert, just seen your post. You are right it is pure magic. :cheesy:
Title: Re: NGC7000 and area
Post by: Whitters on Sep 14, 2009, 23:51:18
Plate scale info for each individual frame.

x 4 Deg, 44 Min, 50.5 Sec
y 3 Deg, 32 Min, 48.7 Sec
d 5 Deg, 55 Min, 33.7 Sec

Starlight express MX916 Chip Size 8.7 x 6.5 376 x 290 pixels
Title: Re: NGC7000 and area
Post by: MarkS on Sep 15, 2009, 05:43:25

Magic!
Title: Re: NGC7000 and area
Post by: Daniel on Sep 21, 2009, 14:59:45
Also try layer masking in photoshop, very easy to get rid of joins that way!

Daniel
:O)
Title: Re: NGC7000 and area
Post by: Whitters on Sep 21, 2009, 21:18:38
Hi Daniel, Thanks for that, however the main problem I had with photoshop was when rotating the image it introduced artifacts around the bright stars, Maxim did not have this problem. Any ideas on how to avoid introducing those artifacts?