atik 383L banding / ice problems

[scirocco1]

Hello, I have constant trouble with ice on my 383L+, I've already swapped a dessicant set. The problem is that somewhere in the system dew is formed, and it gradually cleans itself up in 15-20minutes, but it's kind of annoying.
Another problem I have some ugly vertical banding patterns on the 'left' side of the chip, I can get rid of it with dithering but I wonder if it happens to other 383L+s, too.

vertical banding problem
http://www.scirocco.ro/tmp/masterbias.jpg
http://www.scirocco.ro/tmp/masterdark600.jpg

ice problem:
http://www.scirocco.ro/tmp/383/frozenflat3s.jpg

[niteman1946]

Whoa, .. thought my icing was bad!
Here is my theory on the icing.  The only thing between the image chip and outside world is the shutter.  And when it's wet out and you're imaging (especially long exposures), you can get into a downward spiral.  I have had success with rotating the dessicant a couple of times in a row -- and letting the camera sit for 24hrs. Also, make sure that the o-ring is in place at the dessicant plug.
Of course, this is just my theory.  And I've found that I usually change my theory on idiosyncrasies of this camera (i.e. banding, vignetting et al) on a weekly basis.
Hope you get it worked out ,

Mark
 

[Lex]

Hi guys,

The banding comes due to a non light hermetic closing of the MS. Try to put the lens cover on or use a black filter to take your darks and bias's.
For the moisture problem, unscrew the dessicant plug, take the dessicant out. Take your camera into a warm place, put it in a Ziplock together with a pierced photofilmcanister filled with baader dessicant (orange stuff), suck the air out of the Ziplock, close it and let it set for 48hrs +. This should disable all of the internal humidity.

Hope this helps you getting in order to get rid of your negative issues!

Best

[MicroAstro]

Yes, I have those vertical bands in my 383L+ as well. They are mostly taken care of by bias frames but not completely. They are there whether the scope/camera are covered or not. I've reduced them by carefully isolating my power supply and the power wire so I think the are noise from crosstalk in the wires or a ground loop but I've never managed to eliminate them completely.

I've never had ice or dew, but I store my camera in a Pelican case with a desiccant box when not in use.

...Keith

[CarlightExpress]

The only thing between the image chip and outside world is the shutter.

And a piece of glass

Mine cleared up after about 45 minutes, I have also read somewhere if you cool it down in stages of -5 degrees until you reach your desired cooling temperature the issue also doesn't surface, however not what I would expect ot have to do

Here's one of my Luminance Flats with the Fractals

Clear Skies......And Clearer Imaging Chips
Simon

[NickK]

That's quite bad.. before I changed my desiccant it looked a bit like a christmas card. Changed once ready for the winter season.

Makes me wonder if a CO2 flush whilst changing the desiccant would help.

[niteman1946]

And a piece of glass

I stand corrected.

Mark

[CarlightExpress]

I'm still having major ice problems, and I've also replaced the Decedant with the spares that came with the camera, it takes about an hour before the ice totally disappears

[NickK]

Hmm sounds like there's more water rather than just a bit of vapour. I'd contact the support email address in the forum sticky.

[scirocco1]

I have found a way to avoid ice problems: I am progressively lowering the setpoint by say 5 degrees / 2-3 minutes until the desired value (meanwhile I do other things like calibrating the autoguider, focusing, etc). With this method I rarely get into trouble now.
Hope it helps.

[chrisjbaileyuk]

I have found that it can take two tablet changes to fully dry the chamber out. If you have two sets, bake 1 and put them in the camera. Run the camera through several temperature cycles over a 24 hour period. Bake the other set and replace after 24 hours. The 383L does seem to suffer vapour ingress over time but the above has worked for me even with major icing problems.