M51 - First Light with ATIK-16HR

Interesting comments guys. I suppose you need to take that image for what it is to understand what is says about the camera. Remember, this was a first light test image with nothing tweaked. Only 20 mins total integration time! No post processing at all. Hopefully I'll have something a bit more representitive later on when I process a much more extensive data set of M81 which I also captured last night.

Dave: The CCD is the SONY ICX285AL EXview HAD CCD (data sheet linked) 1392 x 1040 resolution with 6.45micron square pixels. Just as a point of interest, I priced that very CCD chip a while back and it costs £485STG!!!

One thing that surprised me and I'm sure this was just my inexperience with TEC cooled cameras is that noise seemed to decrease as exposure time increased.

Lets see what M81 looks like later.
The other thing that surprises me is how light pollution doesnt cause nearly as much problem as with the DSLR.

I suppose the obvious question is would I buy this camera considering it costs around €1800. Without question yes, I've already brooched the subject with the missus!! I may even look to buy this very model.

Nice one Dave - sounds like your getting youself a camera to keep you satisfied (for a time at least).

Remember, this was a first light test image with nothing tweaked. Only 20 mins total integration time! No post processing at all.

Ah, I thought that was a final image, there is serious potential there Dave,
looks like a great camera that will give you great milage.

Interesting that you found that its less susceptable to light pollution then a DSLR.

A cracker Dave

Interesting that you found that its less susceptable to light pollution then a DSLR.

Any ideas why this might be? I'm at a loss to explain. Maybe when I get on to taking LRGB images it might become clearer. I always wondered why DaveMc never had problems imaging galaxies from light polluted celbridge. Obviously to do with it being monochrome CCD.

I think the reason maybe more to do with the CCD than anything else.

Don't forget, the DSLR's are (mostly) *not* designed for astrophotography. Astronomy CCD's are chosen on the basis of parameters such as dark current, readout noise, QE, pixel size etc etc.

The DSI is a colour CCD though I always image in mono (colour processing is four times the work and 10 times the heartache ). Monochrome CCD's would actually be even more sensitive than the colour versions.

The advantage over the DSLR is as mentioned above plus the DSI has (rudimentary) cooling - somethig the DSLR's do not have. This, probably above all other factors, is the main reason why noise is less of an issue with an astronomy CCD imager than a DSLR.

That said, the DSI in a dark sky will outperform one based in a light-polluted area, all other things being equal. But not so much in light-poluution gradients - just in terms of darker/lighter sky brightness.

Whilst DSLR's have their place as a dual purpose instrument for taking astro images as well as your holiday snaps, comparing DSLR's with Astro CCD imagers is rather like comparing reflectors with refractors, Alt Az mounts with GEM's or apples with oranges. The astro CCD imager is purpose designed, the DSLR is multi-purpose and because of that, some part of the design has to take the hit. Cooling probably being the primary disadvantage.

For an uncalibrated image with no post-processing and minimal exposure integration, I'm afraid the monthly imaging competition may become a one-horse race... Until I get my next imager of course

Dave