attached image is a stack of 11, 10 minute frames with auto levels only applied no other processing taken on a warm night 23/11
I ran a series of darks (lens cap on) (indoors with the air-con on) today from 90 seconds to 10 minutes and still the same issue, each frame showed a bright band at top
Last time I used the camera was in mid October without an issue
Well Theo checked the camera and it appears to be a light leakage, caused by the camera LED light leaking onto the CCD, via a gap which has formed when the foam which surrounds the CCD has somehow shrunk over time
"On a CCD Labs Q8-HR I have, even at gains of 0 and 1 (on its 0-63 scale), the camera would hit 65535 on bright objects (like the ceiling above my desk). There's no point in running this camera at gains higher than 0 or 1.
Why is there no point? The camera only holds 25k e-. If a gain of 0 or 1 gets me to 0.38 e-/ADU (so that those 25k e- become 65535), running at 0.1 e-/ADU will only serve to limit my dynamic range. Each single electron already comes out to more than 2 ADU."
create a wide range of cameras and CCD
Labs acts as a VAR (Value Added Reseller)
for the cameras (a number of other dealers
act as resellers or VARs as well, including
Starizona in the USA). One camera, the
QHY8, is sold through CCD Labs as the
Q453-HR (formerly the Q8-HR) and a
second, the QHY2-Pro (not to be confused
with the entirely different QHY2), is sold
through CCD Labs as the Q285-M. CCD
Labs provides the cameras with additional
capture and processing software, an install
disk with a manual, assembles the cameras,
does a full quality control check before
shipping to customers, and seals the CCD
chamber following an argon purge to keep
dont know if it is any use, but I saw a similar effect when the wiring to my Peltier failed - however, in my case it was only transient, occuring on one frame as the chip heated up.
Might be worth a look at the cooler and its connections/power supply to make sure that it is drawing reasonable current - could be a high resistance somewhere in the circuit or maybe the Peltier itself has partially failed. If it's not light leakage, it must be heat. all the best Ray
it has been suggested by Theo that it could be a power supply problem
before I install the drivers again
I'll
a) test in a completely dark environment (no ambivient light whatsoever)
b) allow the camera to cool and then disconnect the power to the peltier (the camera has been back to Theo so I assume he has checked that the peltier is cooling)
c) don't know about changing the gain as this has never previously been an issue
Well I tried it in a draw with my gain and offset settings and all the darks (up to 10 minutes where fine) to dark actually I thought something may be wrong (run for 1hr roughly)
so I took it out and did a one second focus to see if it was working (bright image as expected)
shut everything down and switched it off for 10 minutes
then I thought I'd try it out of the drawer face down on a table in my study with a light on, with some Alfoil wrapped around the nosepiece
darks are still dark
I really don't know what's going on here
I'll have to wait for another clear cool night to get it outside for another test
Aaaugh - an intermittent. At least that rules out stray light - it's a power problem.
I would have a good look at the cables and maybe replace the main power lead - those wires look fairly fragile. My problem was poor soldering inside the camera, but I wouldn't open that up unless there was no other option. Probably worth checking with Theo again, now that the symptoms have changed - he knows everything there is to know about these cameras. All the best, Ray
