Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: The Thing on Mar 15, 2010, 20:58:27

Title: Christmas Tree Cluster at Blacklands Farm DSC 14 March 2010
Post by: The Thing on Mar 15, 2010, 20:58:27
Canon 350Da Astronomik CLS-CCD filter, Meade 8" LX90 no corrector or flattener. DSLR Shutter and Canon Utility.
Skywatcher 80AT, QHY5, PHD for guiding.
Processed in IRIS, converted to JPEG from FIT in Irfanview and shrunk x3 and cropped slightly.

(http://ancientlight.amateur-astronomy.org/images/xmastree-iso800-15x360s-350Da.jpg)
Title: Re: Christmas Tree Cluster at Blacklands Farm DSC 14 March 2010
Post by: RobertM on Mar 15, 2010, 21:20:19
Hi Duncan,

That's ambitious at f/10 but your guiding looks good so I suspect there's much more data in there.  Any chance you could stretch it a bit more.  It also looks like the CLS has given you a bit of a colour cast to the green but I'm not sure how easy that will be to remove.

Robert
Title: Re: Christmas Tree Cluster at Blacklands Farm DSC 14 March 2010
Post by: Rocket Pooch on Mar 15, 2010, 21:43:11
Hi Duncan,

I think thats at F10, guiding sorted :-)

Chris
Title: Re: Christmas Tree Cluster at Blacklands Farm DSC 14 March 2010
Post by: Fay on Mar 16, 2010, 08:29:37
Definitely sorted your guiding Duncan, you will see a lot more, hopefully, when you start the black art of processing!!!!!! :lol:
Title: Re: Christmas Tree Cluster at Blacklands Farm DSC 14 March 2010
Post by: MarkS on Mar 16, 2010, 08:43:59

Guiding looks really good but this faint target is almost impossible at F10.  However F6.3 will give you 2.5x as much light which will make a huge difference.

The most reliable option is the Meade SCT rear mounted F6.3 reducer because it will always sit accurately on your scope.  But, as you said, the extra length causes your camera to hit the mount.

So you need to either:
1) Experiment with the (internal) Baader Alan Gee reducer to get it working reliably.
Or:
2) Buy an equatorial mount

Either way, you'll be able to successfully image fairly faint things with your modded 350D.

Well done - you've made a huge leap forward recently!

Mark
Title: Re: Christmas Tree Cluster at Blacklands Farm DSC 14 March 2010
Post by: The Thing on Mar 16, 2010, 13:55:58
Hi all,

Thanks for all the comments. I did this as it was high in the sky. The initial processing was using old flats, just done some fresh ones (camera still on the scope) and am reprocessing. There is a lot more nebulosity in the lights, as you say, it needs bringing out with a bit more judicious stretching. I will also flip the image so it's the 'right' way up!

I think the guiding can be improved further by re-arranging my power leads so the scope has a battery to itself. The dew heater (I suspect) is causing a high oscillation index in PHD as it cuts in and out.
Title: Re: Christmas Tree Cluster at Blacklands Farm DSC 14 March 2010
Post by: The Thing on Mar 16, 2010, 14:40:55
Reprocess with the correct flats and a lot more stretching. Fay, spot the doughnut.

(http://ancientlight.amateur-astronomy.org/images/xmastree-iso800-15x360s-350Da_2.jpg)
Title: Re: Christmas Tree Cluster at Blacklands Farm DSC 14 March 2010
Post by: Fay on Mar 16, 2010, 14:55:01
Well done Duncan, is black clipped?
Title: Re: Christmas Tree Cluster at Blacklands Farm DSC 14 March 2010
Post by: The Thing on Mar 16, 2010, 17:41:28
I have used the Stellar Registration (Global, Affine transformation), Composit 2.5 1 1 15, Subsky and Black commands in IRIS. IRIS seems to do a lovely job on the colours, Deep SKy Stacker seems to make everything grey whatever I do.