Dryer stains on sensor

[Astrofriend]

I have a big problem with getting dryer stains on the camera sensor. It doesn't come when outdoors but afterwards when taking the equipment indoors. From about 0 C degrees to 20o C. For every night it add about 10 new dryer stains. To some degree I can manage it by taking new flats, but better if I don't get these stains on the sensor at all.


The camera is a Nikon D800, earlier I had a Canon 6D, same problem. I have tried to seal the joint between the camera and lens with no success.


Thinking about to place a battery powered heater element in the space between the camera and lens, power it on when finishing the observation and let it be powered on a couple of hours after I brought them indoors.


Or place a dryer cartridge in the space between the camera and lens.


Have any of you solved this problem without too much effort ?


Include an screen dump of how it looks.


Lars

[Leo.G]

Lars I don't live in your low temperature extremes, we drop down to -12c in Winter. What I always do is make sure if I'm taking my camera outside for the night to make sure it's not in a warm room for at least 1 hour before I go outside and when I bring it back in I leave it in a colder room for the night so there's no major temperature changes on the equipment.
I guess I'm lucky, my back room is not heated and maintains close to external temperatures and it's a good place to have my gear acclimatise, including telescopes.

[glend]

I used to build cold finger cooled Canon 450D, and the use of dessicant was mandatory. Even if you try to seal the camera, there is always a risk, particularly if you moving from a very cold dry outside environment into a warm more humid indoor environment.
With my cold finger mods on the 450Ds, it was necessary to only allow the copper cold finger to touch the back of the sensor.

Another useful idea was to try to put a clear optical glass filter in place ahead of the sensor area, and put dry gas in there when you screw it down. This should prevent condensation inside the sensor chamber.

And worst case, it's perfectly ok to clean the sensor surface, there are cleaning swabs sold this purpose.

https://www.amazon.com.au/VSGO-Cleaning-Supplies-Package-Cleaner/dp/B08PFZZM99?gQT=1

[Astrofriend]

Hi Leo and Glen,

You both gave me som ideas. I don't have a low temperature room, but a balcony. Maybe I shall leave the equipment outdoors on the balcony in some box with some heat to keep the dew away. I have 12 volt power and LAN on the balcony so I can transfer the images from there.

I never take the camera and lens apart other when cleaning the sensor, I'm using a swab. The cleaning process is almost 100% perfect so that's not a problem.

Next time I built a new adapter between the camera and lens/telescope I will have an opening in it where I can install a dessicant plug.

How often do you have to dry it ?

Thanks a lot for the answers !

Lars

[Astrofriend]

I have gone through possible ways to reduce the moisture problem. The first I do is a test where I put some desiccant in the space between the camera and lens.

I written it down here and taken some photos:

http://www.astrofriend.eu/astronomy/projects/project-dew-sensor/01-dew-sensor.html

I don't belive this help much but it's easy to do a test how efficient it is.

Lars

[leon]

The best way to deal with this is:

If your camera is at 0 degrees outside, put it in a large sip lock bag and remove as much air as possible and zip it up.

Then just bring it inside and leave it there until it has equalized to the indoor temperature. which maybe 20 degrees a couple of hours at least.

Same as for going outside, leave it in the shed for a couple of hours to get to ambient temp

Leon:thumbsup:

[Astrofriend]

I built a temperature, pressure and humid into the OnStepX driver, it was already ready for thos not much work. With this I have a little bit more control over the weather.

I put som photos of this and wrote some info about it here on my home page:

https://www.astrofriend.eu/astronomy/projects/project-eq6-onstep/08-eq6-onstep.html

Works great.

Lars