DSLR COOL BOX COMA CORRECTOR DEW ISSUE

[Adam J]

Could use some advice from anyone who has made a DSLR COOL BOX.

I have now completed my project, it turned out to be very effective at lowering the temperature of the camera, I managed a 25c drop. However, this caused the coma corrector that attaches the camera / cool box to the scope to significantly drop in temperature also and dew formed on it inside the focusing tube during the imaging session as a result, I image using a 130P-DS Newtonian. It took a couple of hours of cooling for this to occur mind you and as the box is sealed with desiccant inside its only the outside surface of the coma corrector / attached 2" filter that has a dew issue.

Has anyone else had this issue?

Would placing a 15cm eyepiece dew heater around the focusing tube convey sufficient heat into the coma corrector to prevent this?

Cheers,

Adam

[Stub Mandrel]

I can't answer your question Adam, but I'm interested in following in your shoes... do you have a photo of your cool box?

[Adam J]

3 hours ago, Stub Mandrel said:

I can't answer your question Adam, but I'm interested in following in your shoes... do you have a photo of your cool box?

I do, but I decided I am going to put it together into one big piece / You-Tube vid before posting it rather than doing it in dribs and drabs. I am currently in the process of producing some test images with it. As such I would rather not post images of the project on here quite yet but am quite happy to answer any questions. However, you may find that my design is not suited to your requirements at any rate. I only image from my back garden for example and so I chose to use water cooling of the hot side of the TEC to maximize cooling performance. Have attached the first two images that I have gotten from the cooled camera. The Pelican is 4 x 10 mins with a CLS filter and the Vail is 8 x 20min with a Ha filter. They are easily my best so far and I did not feel the need for dark or bias frames in either case. However, I was never sold on using them without set point cooling anyway. I got sensor temps of about -4c across the whole session in both cases with ambient temps of more than 20c.  So if you hang tight for a few weeks ill post lots of information. If you cant wait then there are other projects on here or you could check out Gary Honis's DSLR modification page via google, I found it very useful, though I like to think I have refined the concept with some ideas of my own.