Atik 11000 and oversampling

[petercoxphoto]

Hi folks -

Apologies if this has been covered, but in advance of investing in a CCD camera I've been doing my research. From what I understand, in typical UK/Irish seeing conditions, star resolution will be about 4", which would mean that in an ideal world you would use a camera which will give you ~1.3"/pixel with your telescope.

As I'm concerned about the final print size, wanting to make 20x30" prints and larger for sale, pixel count is somewhat important to me. As I live in south-western Ireland with limited nights of clear skies per year, I don't want to have to make mosaics if I can avoid it - so a large format, high megapixel CCD would seem to be the ticket.

The only one I've come across so far is the Atik 11000 which is 10mp in a (roughly) 35mm form factor. However, it has 9 micron pixels, which would give 3.87"/pixel on a 480mm scope (which is what I'll be buying).

I know that many people do use this combination, but it would seem to be massively oversampling the image. For most nebulae and larger galaxy targets, is that likely to be a problem, or would it instead do a lot to remove excess star 'clutter' (remember, I make images for aesthetics, not scientific imaging!)?

Are there other large format, high resolution CCDs that would be recommended?

Thanks for your help.

Cheers,

Peter

[Davey-T]

No idea, but as Olly is going down the same route I'm sure he'll have good advice when he spots your post.

Dave

[petercoxphoto]

Thanks Dave

[Tom OD]

Peter,

I work at approx 3.5pixels per arc sec. I'm not aware of a camera 35mm in size with approx 6micron pixels. Swings and roundabouts I think. size verses sampling. I know I'm effectively losing data with my set up but I do like the field of view of the set up.

Maybe there is a new camera out there that covers the mid focal lenght full format needs giving a sample rate of 1.5-2.5 arc secs per pixel.

T.

[ollypenrice]

I'll be using the 11000 at 450mm. I expect it to be fine. My take on it is that to get resolution close to the theoretical limit of your system you first need data and very few people get enough, so why get too excited about sampling rate? I'm not expecting to use the 11 meg with reducer (328mm) other than for colour aquisition on large mosaics with Lum at longer FL, though I hope it will do that well.

There is a full frame camera from SX, the H36, and I use one of these regularly. (It's not mine.) It has the 7.4 micron pixels of the 4 meg chip. However, I find it has some issues and, although I wish I could have that chip from Atik, I went for the Atik 11000 without much hesitation.

When you are oversampled a mosaic gives you the chance to drop the image size a little and still have a giant image. Also you can hit key parts of the image - the detailed bits - at a longer FL and blend them in.

This is a great technique and has the advantage of driving you further into the red after buying a TEC140 or whatever.

Olly

[ollypenrice]

Peter,

I work at approx 3.5pixels per arc sec. I'm not aware of a camera 35mm in size with approx 6micron pixels. Swings and roundabouts I think. size verses sampling. I know I'm effectively losing data with my set up but I do like the field of view of the set up.

Maybe there is a new camera out there that covers the mid focal lenght full format needs giving a sample rate of 1.5-2.5 arc secs per pixel.

T.

T'other way round, Dr O'Donoghue.

Olly

[Tom OD]

Emm.. oh yes Arc seconds per pixel. Thats why my pics look like a negaitive!!!!