Hello everyone,
I'm looking for some advice on a problem I encountered during my last imaging session.
I started shooting a new target at the end of May and had a few successful sessions over 3 consecutive nights. But due to bad weather I had to put the project on hold for about 2 weeks. During all this time my equipment was stored indoors, assembled.
Now that the weather has improved and I was able to enjoy a cloudless night, I wanted to resume the project, but I ran into a problem that almost ruined my session.
When I shoot over multiple nights, I spend some time adjusting the framing to match the framing from previous sessions as closely as possible. I do this by taking short 20-30 second exposures, looking at the position of the stars and adjusting the mount position iteratively, which usually takes me 5-10 minutes.
The problem I ran into was that I noticed, while shooting these "framing" exposures, that the image started to degrade.
Here's one of the first frames:
📷 image.png
And here's one a few minutes later:
📷 image.png
(these are just screenshots)
It looked like dew to me.
What do you think? Is it dew?
So I looked at the front lens of my 80mm refractor, but I couldn't see any dew at all. There was some dust on it, but no dew.
Then I unscrewed the camera and took it inside to examine it. I looked at the sensor and again I couldn't see any dew at all. The sensor window looked absolutely clean. So I put it back on the telescope and took another picture.
And this time the problem was gone:
📷 image.png
I've had this problem before, but I used to blame it on the cold and excessive humidity, but this time it wasn't really cold (around 15°C) and not excessively humid.
What do you think?
