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Old 17-04-2013, 08:34 AM
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Shiraz (Ray)
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Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,918
Quote:
Originally Posted by gbeal View Post
A very decent result given short subs, and a total of half an hour, very decent indeed.
Bodes well.
Gary
Hi Gary. Yes, this camera allows short subs because of the low read noise and high QE. with the f4 scope, the optimum sub is 2 minutes for broadband imaging.

I am tossing up between a steel and CF scope - do you find that CF is worthwhile, particularly for focus stability?

Quote:
Originally Posted by Troy View Post
Nice image Ray, well done
and nailed the processing to.
hi Troy - thanks for the comment

Quote:
Originally Posted by alistairsam View Post
Hi Ray,

That looks great. Are you able to post a full frame image?
The specs say that full well capacity is greater than 20k. Does that mean it can't register anything over that? Is this related to the number of shades of grey that can be captured and represented?

How would it perform with objects such as the horse head or Orion that have a wide dynamic range?
Was that on a stock standard gso 8" F4?

Cheers
Alistair
Hi Alistair
.
resampled full frame posted - hope you like coma.

well capacity is a measure of how many electrons can accumulate in each pixel before the ABG overflow mechanism kicks in and drains excess charge. the number of shades of grey is determined by the free space between this upper limit and the lower limit set by the read noise (this free space is the dynamic range). As a rough generalisation, most chips in wide use produce 16 bit signals, but have similar dynamic ranges of about 12 bits (4096 shades of grey) - the Sony chips have relatively low well depth, but low read noise - the Kodak chips generally have deeper wells, but higher read noise. To put this in perspective, the icx694 has more dynamic range than a K8300, about the same as a K11002 and less than a K16803.

This camera should perform about the same as most others on any target, except that, at the same pixel scale, it will take less time to get to a given signal-to-noise level, because of its high QE and low noise.

The scope is a standard GSO with the following mods:
- tube coated in adhesive Al foil
- partially flocked
- custom secondary holder with larger secondary
- strengthened tube around focuser
- strengthened GSO focuser with SharpSky drive
- primary fixed with adhesive tape and clips removed

regards Ray
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Last edited by Shiraz; 17-04-2013 at 09:42 AM.
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