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Old 23-07-2010, 07:39 AM
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gregbradley
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Join Date: Feb 2006
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Quote:
Originally Posted by sejanus View Post
The reason I'm not so keen on a dedicated ccd is because I wanted to do a lot of super wide stuff using my lenses - as well as through the 106n.

Though maybe I'll need to do both slr & ccd eventually.
I am about to do some super wide shots with my dedicated CCD.
Its just a matter of adapters. The advantage would be -

cooling and lower noise

much much higher QE

higher resolution - one shot colour cameras have quite low resolution as it takes 4 pixels to make one colour dot in the image. That is the same as binning an Astro CCD 2x2. So astroCCD in mono then has superior resolution. The gain is not 16X due to clever firmware estimations of the neighbouring pixel values but it is there.

you can shoot narrowband which is much harder and noisier with a DSLR for the above reason.

SBIGs can self guide making it even more convenient

16bit A/D instead of 12 or 14bit in DSLRs (not sure how important this is)

Having said that there are many many super DSLR widefield images around and dedicated CCD imagers don't do lens imaging that often.

However if they do - check out Stephane Guisard's ridiculously good Milky Way image which is a 200 panel mosaic.

Phil Harts Rho Ophiuchi is a spectacular DSLR widefield. I'll see if I can post some links to it and a comparison image from a massive Proline 39 megapixel camera and a Pentax 67 300 F4 ED lens.

Here are some 45mm and 300mm F4 ED images from Richard Crisp and a Proline 39 megapixel CCD cam:

http://www.narrowbandimaging.com/ima...4x15min_hd.jpg


http://www.narrowbandimaging.com/ant...r_rgb_page.htm


http://www.narrowbandimaging.com/m8_...3_rgb_page.htm

And here are 3 images I took with my FSQ106ED and reducer and either Proline 16803 or SBIG STL11:

http://www.pbase.com/gregbradley/image/99385463

http://www.pbase.com/gregbradley/image/124811617

http://www.pbase.com/gregbradley/image/124761790

The FSQ being a telescope gives a finer resolution and to me means camera lenses ultimately cannot compete
with specialised high end telescopes due to higher quality, way less lenses (a 300mm lens may have 9 pieces of glass
each one adds aberrations and scatter and dispersion). But of course telescopes don't go down to 45mm focal length!

Also the conclusion is a DSLR would be hard pressed to match a dedicated astro camera of comparable chip size
(not many match or better a 5D in size) with a decent lens. But skies, processing skills, framing of object, length
of exposure, light pollution may all be senior factors to gear in the final result.


Greg.

Last edited by gregbradley; 23-07-2010 at 08:23 AM.
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