Hi all,
Below first light for my SC3 since I did the Amp off mod. Image represents approx 30mins of exposure with SC3 + 0.5 FR & Astronomik CLS filter (15 sec subs). I've noticed that images are more noisey since the mod.... Anyhow - I will give this a second attempt at DSC (skies permitting).
Fay this is quite an easy target so maybe you could give it a go as well...
Cheers, John
(http://homepage.ntlworld.com/john.punnett/graphics/oas/bubble1.jpg)
John,
Looks very good to me. Not such a common subject. I would be well pleased to get that quality, I have a long way to go, yet, me thinks.
John, what does the amp do?
Fay
Doesn't look that noisy to me ! Well done John.
Thks Fay, Mike.
Fay - The Amp (amplifier) is something that is internal to the CCD - It you leave it ON when doing exposures in excess of say 15-20 secs you start to get a bright glow in the top left corner of the image. This gets progressively worse the longer the exposure until after about 30-40 secs you have 'swamped' so much of the image it is not really useable. The Amp Off mod that I recently did on my SC3 (& you have on yours) enables you to turn off this Amp during long exposure which means you can do much longer exposures without the whiteout issue. The ampoff mod works by lowering the supply voltage to the ccd during exposure the downside of this is I think slightly lower sensitivity & increased noise..
I can show you the effects at DSC.
Cheers, John
John posted some examples of the amplifier's effects in this thread (http://forum.orpington-astronomy.org.uk/index.php/topic,1913.0.html).