Infinity dark current

[kuba_mysluk]

Hi all,
First post here...

Have Infinity colour, Im very happy with it. Great EAA camera.

Here is one of my last photos. Did it during hot night (~20C is hot for my It is overtimed and overstretched (Auto Range Medium) for showing this effect, but it is also noticeable in my prevous pics. Can live with it, as it is uncooled camera didnt expect miracles here. Asked on other forum, got answer: "dark current". Norm issue in CCD.

I add two photos: one is dark @20C, second is Pelican nebula with the mentioned effect.
Pelican was done by C9.25/Hyperstar/CGEM setup, probably without best polar align.
Image movement correction was set ON,

Question:
Why hot pixels are not aligned same as stars, during movement correction? Stars are quite rounded... Is here any threeshold which left smal tiny  pixels untouched?

regards

Kuba

[kuba_mysluk]

and my "dark"

[Steve]

Hello Kuba,

You have a great picture, though as you say slightly overtimed and over stretched.
The star tracking algorithm looks for stars on the basis that they have a size of a few pixels.  The are then aligned and stacked.  Any drift in your mount will cause hot pixels to be drawn out into lines.

I am looking forward to seeing more pictures from you.
Cheers
Steve

[kuba_mysluk]

Hi Steve,
Yes, drift... it was something I suspect, the mount drift. Just ordered Polemaster camera, will try polar align my mobile setup as best as I can.
Never got this results when ambient temperature was 10C or bellow (just checked old photos). Even on Alt Az Celestron EVOLUTION I used before, which have natively far more drift from field rotation.
Im quite sure so it is also thermal issue. One of last nights I catch three photos one after one, as test of IDAS D1 filter under my skies. The result was worse with time.. Look like camera's sensor going hot with next and next shot.

Pls take a look at the photos, all are done with more less same total exposition time, and noises are bigger and bigger. I see the mount drift and its direction, exactly same as direction of strokes on my pisture.
Last one was taken with short subs, wasnt help at all.
Count of subs and exposition are in filename, last four digits is time.

Next warm night will try disconnect the camera for a while, maybe it will help a little bit.

question: Does camera case is thermally connected with the back of sensor?

regards

Kuba

[kuba_mysluk]

next

[kuba_mysluk]

and the last one

[Steve]

Thanks for sharing.

Yes the infinity case does conduct heat away from the sensor.

If you really would like to push the camera you can also traditional long exposure software such as Artemis Capture, and do the processing the next day.

best
Steve

[kuba_mysluk]

Thanks for answer,
Did some test more, and hot pixel removing is really good in Infinity software. In normal european night with 10-15C it work well, and very well around 5C or bellow.
It have own limits, and more than 20C is probably just too hot.

Probably I can put DYI Peltier on the back, but problems with moisture (or even ice) isnt worth it. Especially if on normal night it can produce such images as below.

K

[StarMike]

Maybe just DIY some sort of fan onto the camera instead of the peltier.  The you don't have to worry about condensation.  I have used mine in 90F (32C) and it did pretty well.  Some summer nights in Florida it does not cool off.  I do see more noise when it is that hot