QHY8 - Still cant get it.

[Gama]

It does look like an offsett. Remember that Nebulosity and Maxim use different figures to represent the offsett and gain.
A gain of 1 and offsett of 65 is NOT the same in maxim. So you cant just enter the same numbers..
Can you post a single sub showing the Histogram ?.


Theo.

[allan gould]

Image capture was in Nebulosity and I used the tutorial from Neb to determine the gain and offset for my camera. Ive attached a sreenshot of a single frame before and after de-bayering in Nebulosity.
Left - not debayered right - debayered

[Gama]

Allan, can you send me a Crop of 1/4 the image in a FIT format to my email.
Want to check a few things.
Make sure its NOT converted to color.

Theo

[CometGuy]

Are sure this isn't condensation on the CCD coverglass?

Terry

[allan gould]

Originally Posted by CometGuy

Are sure this isn't condensation on the CCD coverglass?

Terry

Absolutely sure as I run a heating element in the camera (new for QHY8 from Theo) and previously I always used a 2" dew heater strip around the front of the camera.
I only use Nebulosity to capture with the QHY8 - dont have Maxim

[allan gould]

Originally Posted by Gama

Allan, can you send me a Crop of 1/4 the image in a FIT format to my email.
Want to check a few things.
Make sure its NOT converted to color.

Theo

Theo - file sent to your email. Not colour converted.
Allan

[Gama]

I checked your file Allan, and under Maxim, it shows a clipped image.
I thought at first, maybe its because you cropped the image, and thus has changed the Histogram position, but i also cropped one of my own images, and the Histogram barely moved..
Attached is the image i got using Maxim to display the image..
Very strange.

Theo

[TheDecepticon]

One of the images is very noisy. I know there are some capture problems if the TEC is not working well. Is the camera getting warm at the heat sink and the fan blowing warm air? Have you checked that all components are getting their respective power. Why not check out the QHYCCD Yahoo group? You might get some info from there.

[allan gould]

Found the problem. Originally I was using TVDEE drivers but changed to QHY drivers to get the 4x4 binning. Now I find with this installation Im getting a lot of read out noise and the offset settings have to be increased to ~120 to get a pixel reading of ~1000. Previously my offset was 50-65 to get the SAME value with TVDEE drivers. I have gone back to the TVDEE drivers as these give absolutely noise free images.
When I upgraded to the QHY drivers I assumed that the offset settings would be the same- not so at those settings for the TVDEE drivers 65 offset, the ADU reading was 0.
Find it interesting that now Im getting download noise with the qhy drivers and not TVDEE drivers????

[Gama]

The offsett numbers are not identical, or should i say, they are not absolute, but rather relative to its own formulars/calulations.
The same goes with the gain, its all relative to its own programming.
I use the original drivers from QHY, and i have no noise, and images are fine..
But im glad your back on the wagon..

Theo.

[allan gould]

Theo and others, thanks for your valiant efforts. Ive tried all the available drivers and settled on QHY drivers which I can now use noise free and with 1% Gain and an Offset of 111. When binning from 1x1 to 2x2 and 4x4 the ADU goes from ~350 to ~750 to ~1200 and so this looks like the settings for my camera. With the TVDEE it was 1%Gain and offset of 50. Guess that its a lesson for all to check it if you change your parameters. Noise may have been due to partially seated s video cable not being all the way in.

Allan

[multiweb (Marc)]

Wow. Pretty amazing how significantly drivers can change the behaviour of a camera. I reckon I'll stick with what I've got now. Seems to be working so far. Glad it's all sorted out for you now. Back to imaging