Opticstar DS-335 ICE - peltier doesn't work ?

[jarbi]

Hi Everyone,

I am just testing my new camera, and made some 10 min darks, after letting the cooling run for almost an hour. My dark frame is showing lots of BIAS noise, so the peltier cooling doesn't seem to work . I have attached a screenshot with one of the darks and the histogram from Nebulosity.

Is there anyone to advise how can I make further test to see what can be wrong here ?

cheers,

Janos

[SteveP]

Hi Janos

That's an interesting dark frame. I'm puzzled why you believe it is 'bias noise'. In a 10min dark, I'm not convinced you could distinguish 'bias noise' from everything else which is happening. Why not take a conventional bias frame to confirm your assumption?

The dark looks like it contains a lot of light seepage. If i were you, I'd also check all the connections in your optical train, especially those close to the camera

Steve

[martin_h]

Looks like light seepage to me too...Try taking a dark in the dark to see if there is any difference.

[jarbi]

Thanks Steve and Martin, I have indeed overlooked the obvious . I was taking the darks by using the threaded cap of the camera only, and that is apparently not dark enough.. Now I have put the camera in a dark box, the result speaks for itself . So there is no problem with the peltier cooling.

Just to demonstrate how dark the dark frame is, I was trying to stretch it in Photoshop, see the attachment. There are only some hot pixels visible on the top part of the frame after extreme stretching, the rest is just pitch black.

cheers,

Janos