Quote:
Originally Posted by mike geisel
Hi, I took this image of Thors helmet last night Ha, O111, Hb all 3minutes , all 20 subs. I haven't finished processing yet and hope to improve the colour. There are two problems I don't know what to do about. First the background is streaky. I have heard this may be due to temperature variation of the sensor and as it was hot last night the cooler at max shifted from -14 deg to -18 over the 3 hours. I have also read it could be flexure in the guide scope. Secondly there are a number of 3 coloured streaks where something has moved over the 3 hours. Are these hot pixels? If so any advice on removing them. I have Pixinsight but am only just starting to learn it. Image taken Sky Watcher Esprit APO150 EQ8 mount ZWO ASI 1600mm-c. Guiding was via a 80mm 600mmFL refractor mounted on top with an Orion pro auto guider and PHD2. Sorry I don't frequent forums often and I couldn't work out how to attach a reasonable size copy of the image so I have pasted a drop box link to the image. Will that do?
https://www.dropbox.com/s/ym448vhe3x...20RGB.jpg?dl=0 |
Hi Mike
The bright 3 coloured streaks will most likely be hot pixels. When you have run image registration in PI the hot pixel ends up in a different spot so you get a streak as each image is shifting slightly. I am guessing you have a polar alignment issue, how do you Polar Align and how confident are you that it is correct? The fainter streaks are caused by the same effect on pattern noise in the sensor. Best bet is most of that will be got rid of by getting a good set of darks and bias frames, you didn't mention that in your post so I assume you have not used?
Malcolm