Not the Desiccant

Forums Imaging odd results creating flats Not the Desiccant

Rodger King

Although dewing and the desiccant sounded the potential problem, it turned out to be something else. 

As I dismantled the camera off my telescope to prepare to dry the desiccant, I noticed the fiield flattener I was using on my refractor looked a little dirty.  However, when I tried to clean it it seems the dirt is caught between layers of the flattener I cannot reach.  See image.

Oddly the appearance of this dirt varies and a stable room temperature looks like it completely disappears.  Must be at its worst when its super cooled ?

So I redid my flats with the field flattener removed and the images are all fine and do not change over time.  So no need to dry the desiccant.

However I have had to send the field flattener back to the company I bought it from to be professional cleaned.

Still very grateful to you for your advice though.