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Old 05-13-2008, 07:16 PM
astroseeker52 astroseeker52 is offline
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Thumbs down Bloated stars

Team: I use the Starlight xpress H9C with the hyperstar (2nd gen) and NS11gps, and I have bloated stars after combining (my normal stack up is: 6 x (10 shots @50 sec each). Individual shot the stars look normal, small and tight.

Any ideas what I could be doing wrong to get the bloat star results? Programs normally used: MaxIm DL and PS2

Thanks Dale
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Old 06-11-2008, 03:17 PM
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Ozy Ozy is offline
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Hi Dale,

Are you using a filter on your hyperstar? The H9C does not have a UV/IR block on it, and as a minimum, you should be using that for all imaging. Light outside of the visible spectrum will cause star bloat if it is not blocked.

Also, focus acuity at f2 is critical. What are your methods for focusing? Have you tried an auto focuser? Is your hyperstar properly collimated? All of these factors can impact your star size.
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Old 06-23-2008, 05:00 AM
SteveL SteveL is offline
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I too see "bloaty" stars during post-processing. They dont appear i the final stacked image, only during the processing do they start to get a bit overwhelming. Could be a product of imaging at f/2, or could possibly be an issue with any filters inline during the image aquisition. I tend to use either Astronomik CLS or Hutech IDAS, but still unsure which one actually does the better job of removing Light Pollution.

I use QHY8 on a C8, FocusMax and the FeatherTouch/Microtouch system for focusing, and the Hyperstar is collimated pretty much every time I use it with CCDInspector.

I get rid of the bloaty stars by creating a star mask near the end of the processing, expand by 5 pixels and feather the mask by 3 pixels (these figures can be varied as required), copy the stars off the current layer, paste to a new layer, and then run filter minimum on that layer, adjust transparency of top layer to taste.

I`m sure there are better or alternative ways of reducing the bloaty stars.
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