383L+ Mono calibration problem

[DaveAus]

I use a 383L+ mono and autoguide with PHD2. Recently I have encountered a problem when using Dawn. Attached is a composite of 5 cropped screenshots. Each of the first 3 (labelled A, B and C) shows a Histogram stretched view of the top-left corner of one of the calibrated lights after dark frame subtraction, flat frame division and alignment but before final combination. There were 9 light images in all and these 3 snapshots show the calibrated status of images 1, 5 and 9. In each case I have superimposed a crosshairs over a prominent star. The fourth screenshot (labelled D) shows image 9 but with all of the crosshairs in screenshots 1 to 3 superimposed. This demonstrates the direction of drift between the 9 images. The fifth screenshot (labelled E) is of Dawn's combined result (similarly histogram stretched) and it shows the problem that I'm having. As you can see, the result is very streaky and the streaks are aligned in the same direction as the drift mentioned above. This is causing no end of problems when later processing the image in Photoshop. Can someone please explain what is going on and how I can rectify the problem?

Thanks

[ChrisGolden]

Hi Dave,

Sorry to see you're having problems. Could you email us the actual images you are using so that we can have a look ourselves. Please send them to support@atik-cameras.com.

Thanks

Chris.