Good Information from both of you. I will read up on these topics during the week, I still have the RAW files so I can try to process them again using the non-linier curves; you are right I used a crude linier scaling. The raw data should be ok so I have to get more familiar with Photoshop. I did most of my colour mixing in CCDSoft and used ACDsee to play with the levels.
The guiding issue is more an issue with the mount itself. More often than not the calibration from ccdsoft's autoguide using the STL's internal guider was failing. I had to turn the mounts gain to autoguider to 200% (20) (max) and calibrate for about 10 seconds. Sometimes it works, other times not. Just watching the Guide stars movement between calibration frames was not resulting in 4 clear directions.
Even when it works it does not seem as good as the DSI2, Piggybacked Megrez88, GP-USB and Phd results.
- Dave.
Quote:
Originally Posted by jase
Alex is on the money... in simple terms, clipping is the loss of valuable data.
White clipping = loss of details in the highlights - i.e. stellar profiles and/or bright features.
Black clipping = loss of details in the shadows - i.e. faint/dim nebulosity.
What are you using to stretch the data? Linear stretches i.e. levels is limiting as when you start to bright the image to show the faint details, it is also increasing the highlights at the same proportion/scale. You need to get comfortable with non-linear stretches i.e. curves. This will allow you to maintain the bright areas while enhancing the contrast of the faint/dim. I wouldn't recommend processing objects differently and relayering them unless you're experienced with photoshop tools. It can be difficult to get the right brightness/contrast so they integrate seemlessly. I've done it on a few images. Feathering and masking can greatly assist.
Strange you're having problems with self-guiding. Bin the guide chip 2x2 so you boost its sensitivity. Finding a guide star with the FLT132's focal length would be easy - especially with the field flattener. Make sure you calibrate regularily.
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