Webcam Weirdness, Info required.

[astromerlin]

Hi, I'm still using a webcam for imaging and one thing I'm having a problem with is when on long exposure mode I sometimes get a blank frame ie: no image at all. These happen frequently and the shorter the exposure the more frequent they are. I also get frames with a light horizontal bar on some frames.

I have spend weeks trawling through all the info on the web to see if this is normal for a webcam with an LX mod but have found no info.

I've set the frame speed to 5fps and shutter to 1/25 (Toucam Pro II)

but no amount of altering settings seems to affect it.

I really need to use this webcam for a guidecam and the blank frames are going to make that difficult.

I recently modded my SPC900 to LX with all the amp-off and bias trimmings and it works very well, no dead pixels and no amp glow at the exposures I was using the Toucam at.

But I noticed the first evening I used it that I was getting the same effect with this one as well.

I was wondering if it was something to do with using a CD4066 chip instead of the chip Steve Chambers used. The Toucam Pro I'm using originally came from Astromiser which used the 4066 chip. I must admit it has me stumped, I've read that other people use modded webcams as guidecams so is it something I have to put up with or is there a fix or am I not doing something right?

Has anyone else had this experience?

Cheers

John

[Parallax]

I was also having this problem, which is why I bought a QHY5 in the end.

The following is taken from the PHD help file :-

LE Delay: If you are using a long-exposure modified webcam there is a magic "delay" value that lets you grab the correct video frame (the long-exposure one) out of the stream of blank or short-exposure frames that come on before and after this long-exposure frame. Typical values are about 10-20 ms, but this will vary from system to system.

Hope you have more luck that I did.

Steve

[astromerlin]

Hi Steve, Thanks for that info, I'll have to take a good look at that help file.

Cheers

John