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Old 23-04-2013, 01:22 AM
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LewisM
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Odd SX issue

When I was imaging on Saturday, about 3/4 the way through my entire set for the night, my SXVR-M25C did something odd - it seemed to lose light intensity.

I was debayering in MaxIM between shots (set to Autosave). Was getting GOOD colour and brightness, then suddenly the brightness and colour rendition muted for the next shot, and stayed that way. No cloud, no frost over camera face or focal reducer, no dew.

Noticed it again tonight, but from the start. Still producing a good image, but seemingly it is now LESS sensitive. Almot like I now need to do a 10 minute exposure to get what previously only took me 5.

This has me concerned. When the camera "dimmed", it was running at -4.4°C. I had a small program glitch in between (MaxIM stopped responding momentarily), and the cooling reset than came on again. Could this have thermally shocked the sensor, damaging it?

Got me really worried. Photos are still good, just seem less intense.
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Old 23-04-2013, 06:39 AM
PeterM
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Hi Lewis,
I have noticed what you describe with my SXVRH9.
It sometimes loses the light intensity now and then in 30second images. A good example for me was a test shot of NGC5189 the planetary in Musca, one 30 second image was fine showing tremendous detail, the next you could barely see the pn
My other camera the older SXVH9 has never done this in 6 years. But the newer camera is cooled and I wonder if there is something in what you note about the cooling.
Overall in several thousand images taken with the SXVHR9 I might see the effect you describe perhaps in a few images per night. Has had me wondering, maybe time to pose the question directly to Starlight Xpress or on the Yahoo site.
Anyone else noticed this?
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Old 23-04-2013, 07:21 AM
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Peter, I have shot off this link to Terry at SX, so hopefully he has some feedback when the UK wakes up.

I am going to try it on a bright target like Eta Carinae again tonight, and see what happens. I did my first ever lunar imaging with it last night, and had to set the exposure to 0.002 sec, so it is still sensitive enough, just what the chip spits out is maybe not so.
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Old 23-04-2013, 08:25 AM
cfranks (Charles)
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Do you save the images in Fit format? The Fit's header will show some information about the camera including the electronic gain. A comparison between 'bright' and 'dimmer' images might show a difference in something.

Charles
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Old 23-04-2013, 05:12 PM
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Terry got back to me promptly (Peter, could you email him please too to tplatt@starlight.win-uk.net about yours). He emailed me a copy of the new gain script, as the older one was unstable.

Great service as usual!
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Old 23-04-2013, 06:29 PM
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good that it's sorted Lewis, what exactly is a gain script?
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Old 23-04-2013, 08:55 PM
PeterM
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Thanks Lewis,
Just emailed Terry. I guess the gain script is a firmware upload is that right?
Muchly appreciated. never got round to chasing up myself as the original camera is the one that does most of the work.
This is what makes this forum so very useful as well as friendly...people sharing issues and resolutions.
Thanks again
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Old 24-04-2013, 07:33 AM
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No problem Peter. Hope it works. I flashed mine last night, and yes, the camera worked afterwards, so fingers crossed

Lewis
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