Help with images

[vlazg]

:help:
Last night i began an imaging session using SGPro. I had set up to take 9 images RGB in that order, 5minutes, and after a few went and had a nap
( why is it if you dont fall asleep everything goes ok but if you fall asleep everything goes haywire)
When i examined the images , the R was fine and the first 4 of the G were ok and the pattern shown in the thumbnails ( 5 to 9) appeared but strangely enough exactly the same happened with the blue, the first 4 were ok and exactly the same pattern occured , ie images 5 to 9 had the same pattern.

Any ideas? A software glitch or something more sinister.

Any help would be appreciated.

Thanks

George

[billdan]

Gooday George,

That looks like the classic signs of dew forming on the cold CCD window.

You will need a dew heater wrapped around the spacer between the CCD and the Filter wheel.

Cheers
Bill

[Slawomir]

I agree with Bill - something's fogging up to my eye.

[vlazg]

Ok, Thanks Bill and Suavi, that is an option but why did the pattern appear from 5 to 9 in the green, miraculously disappear when it changed to the blue filter, and began to reappear in the same order and pattern images 5 to 9, the dew would not disappear then reform in the exact same manner.???

[billdan]

Good question, maybe the cold of the CCD window is being transmitted onto the filters and it takes a bit of time to attract the dew, that why it only shows on subs 5 -9.

[vlazg]

OK, i will try a dew heater next time, the camera is screwed directly to the filter wheel, is it ok to put the dew heater on the camera extension , will it affect sensor cooling?

[DJScotty]

Is sgp taking complete runs of each channel or switching between filters each shot?
Does that make sense?

[vlazg]

Yeah Scotty, i thought of that but it is making complete runs before filter change

[billdan]

The peltier cooler is behind the sensor so a dew heater on the camera throat will not affect it.
Good question by Scotty, if SGP is taking sequences RGB in rotation order that could also explain why it takes up to subs 5 - 9 to show up on each colour.

[vlazg]

Thanks Bill, i answered Scotts question..... complete runs, but i really think you and Suavi are right , before nap no dew, after nap it was quite dewy.
:)