Peltier-cooled Canon: first light.

[MarkS]

IC1805 - this is first light for my peltier cooled Canon taken under last night's (Sunday 8 Nov) murky sky.

16 x 10minutes at ISO 800.  Canon EOS 350D on ED80 with 0.8x focal reducer and using Astronomik 12nm Ha clip filter. This gives a focal ratio of F6 and a focal length of 480mm.  Ambient temperature was around 2C and the CCD was cooled to around -17C.

I very quickly processes the data last night.  It needs re-processing to remove the residual amp glow in the extreme top and bottom right corners.



Here is the full frame image, slightly cropped and 2x2 binned:

http://gallery.orpington-astronomy.org.uk/albums/userpics/10046/heart08112009.jpg

Mark

[Fay]

Well mark, you would say it was taken with a dedicated ccd camera. Fantastic result. Did you desaturate in PS? Is that a 2" FR?

If you are going to do it as a business, please put me on the list!!!!

[MarkS]

Did you desaturate in PS? Is that a 2" FR?

I applied dynamic range compression in IRIS.

The FR is the William Optics MkII.

Mark

[RobertM]

That's really fantastic result Mark.  There's excellent detail in the nebula, good depth and focus is spot on.  Parts of the nebula are saturated as are are quite a number of stars but it's also highlighted some big problems with my processing which is good and focusing which I'll have to work on.

It was definitely worth while doing that peltier mod, I wonder whether a cooled 450d would be any improvement!

Dynamic range compression - interesting, so that's how you kept so much detail.  You'll have to show me sometime.

Robert  

[MarkS]

Thanks for the comments Robert.   I was certainly quite pleased with this result.   

The saturation of the nebula and stars was something I missed when doing the quick processing - the raw data is fine - I just need to process a bit more carefully.

Mark

[Daniel]

Fantastic First light Mark, as Robert said, the amount of dynamic range you retained there is great, and very smooth for only 16 subs.

Daniel
:O)

[Mike]

Great image Mark. But... Why in B&W?

[MarkS]

Great image Mark. But... Why in B&W?

To make a sensible test, I wanted to get the background signal very low, so I either had to go somewhere very dark or go narrowband (which is what I did with an H-alpha filter).

It was an interesting experiment.  It shows that, with cooling, narrowband becomes quite feasible with a DSLR.

The B&W image is just the red channel - the green and blue channels contain hardly any data except for a few (very dim) stars.

[Mac]

very nice image.

[Whitters]

Lovely image Mark, focusing is spot on, fantastic detail.

[JohnP]

Mark - Very nice indeed you must be well chuffed with that for a first light after all your hard work. Like others say compares very well with a dedicated astro CCD. Lovely FOV but slight distortion at edges (particularly top left) - I guess that's down to spacings etc. (it is very minor though) Response from camera seems great and noise very low for such limited exposure...

Look forward to more

[MarkS]

You've got eagle eyes John!

The CCD is not parallel to the image plane:  bottom right the stars have radial "smears" and top left they are tangential.  I need to investigate the cause and fix it.

Mark

[mickw]

CCD is not parallel to the image plane

Some vandal's probably jammed a lump of copper pipe behind it 
I'll get my angle grinder 

[Tony G]

Great image Mark, and the ISS is nowhere to be seen. 

Was the additional weight of the cooler a problem or not?

Tony G

[MarkS]

Re-processed here:
http://www.markshelley.co.uk/Astronomy/2009/heart_08112009v2.jpg

Central stars still look burnt out.  I seem to be unable to preserve detail both in the nebula and in those central stars - may end up having to layer them in PS.

Mark