Future Cameras: Dessicant plug

Luxo

Here the humidity ranges between about 95% by day to 99% at night for much of the year. Even though my ASI2600MC DUO supposedly has a dew heater (and I set it on) it's usually impossible to cool the camera much below the dew point without dew forming over the coverglass. Below 0C is impossible even in winter. The single window and heater are not effective here.

As I use a filter in front of the camera which closes the space immediately in front of the cover glass, would it be possible to include a desiccant plug in the camera body to dry the air in that space ? Or perhaps a double window (like double glazing) over the sensor ?

Tech@ZWO

Luxo All our cooled cameras have desiccant inside the camera. For high high-humidity environment, you can run the dew heater for a few minutes first, and then turn on the cooler to try.

Luxo

Sigh. OK my error.

Camera is a 2600MC DUO, and I am pretty sure the desiccant is ineffective and the heater does not work - a ring of condensation or frost forms every time I try to take it near 0C. Below 0C is hopeless - the images from the last three sessions all show there is a big ring around the centre typical of condensation on the cover glass.

Today I took the camera indoors for a good look at it under bright light. The water film causing trouble appears as an oval in the centre of the cover glass over the main camera. Disassembled the camera, replaced the desiccant.

First issue is that there is a rectangular black rubber shroud around the sensor, with an O-ring that seals it against the coverglass. This the desiccant cannot remove water vapor from the air between the sensor and the coverglass - it is effectively sealed in.

So I removed the coverglass out. There is an O-ring seal under the glass, I took that out and re-greased it, and replaced the O-ring and inserted a new coverglass I bought a while back.

The desiccant inside was light beige, which I assume means it was supposed to be OK, but clearly it wasn't doing anything given the condensation right in the centre.

I had a good look at the heater as well. I cannot tell if the heater works, or not.

Lastly, IMHO the mechanical design could be better. I would have put the dessicant under a plug at the side of the camera, so it could be changed without having to remove the front plate exposing the camera sensor.

It is powered up again and running... will take a few sessions on the scope to confirm its OK again.