Strange Dark File

[cpuetz]

Dear community,

I own a new ATIK 383 l+ and made my first attempts with it.
I took some pictures of DWB111 (the propeller nebula) with Ha and SII narrwoband filters.
The camera chip was cooled down to -25°C, each subframe was taken with 1x1 binning
and 10min exposure time.

After that I took the dark frames with "looping mode" from the ATIK Artemis software, only the
telescope optics were closed (in looping mode, there is no dark frame option, as far as i know).

Please have a look an my frames, attached as a screenshot. They show the light frames (Ha and SII) and a dark frame.

On the right side there is some kind of illumination, maybe from the ventilating slots ?
My laptop display was turned on during light and dark frames.
Any idea about the cause of this ?

Thanks in advance,
Christoph

[patholland]

Hey Christoph, this looks like either amp glow (unlikely) or a light leak. Can you try taking darks from a truly dark place (such as a closet or large cardboard box). This will help determine the cause.

-Pat Holland

[cpuetz]

Thanks for your reply ! I will try to investigate further.
How do you take (many) dark frames in ARTEMIS ? With the loop function or as some single frames with the "drk" switch turned active ?

Greetings,
Christoph

[andysea]

I take darks at home to not waste precious imaging time. I usually do it at night in a room with the lights off. If it's during the day I wrap the nose of the camera with tinfoil making sure that the vent slots are not covered. I use the capture software and setup a sequence just as a regular capture sequence but I check the "dark" box in the camera control window.
Is there another way to capture darks?

Andy

[cpuetz]

Hello,

I retried taking my darkfiles at home (with the same temp).
Now they look better than before. So I assume there was a "leak" in my previous
setup, causing the illumination at the right side.
There seems to be very slight amp glow, but this is ok for me.

Currently I still use the Artemis Software and I use the loop  function
with the single exposure window, but with the drk option turned on.
(see attached new screenshot).

Question:
So it is possible to take darks within the "sequence" function, when the dark is activated ?

Kind regards, Christoph

Kind regards

[patholland]

Hello Christoph. Glad to see you found the issue. I suspected it was a light leak but couldn't be sure until you tested further. If the balance of the light is some kind of amp glow, you will not have any issues removing it (darks will subtract the glow from the lights). I cannot help you with Artemis, I use Maxim DL with my Atik camera. Do you have access to Maxim DL?

-Pat Holland

[cpuetz]

Hi Pat, thanks again for your replies.
No, I don't own the MAXIM DL software, maybe in future.
But the way i do now is acceptable for me, as I can build a "darkframe library" at home
for each temperature and exposure time. As far as I know, this lib can be "refreshed"
every few months.

regards,
Christoph