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Old 10-12-2012, 07:22 PM
swannies1983 (Dan)
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Reflection around Alnitak - newer RC8

I got myself an RC8 from an IIS member and it's one of the newer ones where the reflection issues have been sorted. I spent Saturday getting it organised for imaging and did a short session last night on the Horsie. I collected 1.5hrs using my modded canon 30D (300secs @ ISO1600). I was guiding with my 60mm Tasco refractor. I also used a LPS filter.

I did a quick stacking job this morning with just a little bit of processing. Now, I am aware of the initial problems with internal reflections of the older RC8 scopes but does anybody have any idea what the large reflection is around Alnitak? There's also a dark "vain" that follows the spike. Is this normal?
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Old 11-12-2012, 09:55 AM
Poita (Peter)
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I'd remove the LPS filter and see if the problem disappears.
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Old 11-12-2012, 11:02 AM
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mithrandir (Andrew)
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I would have guessed reflection off the CCD cover glass back to the LPS and back to the CCD. In some situations you can tilt the filter so the reflection falls off the CCD but I doubt you can do that.
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Old 11-12-2012, 11:46 AM
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Take off the LPS filter and see if the reflections go
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Old 11-12-2012, 12:27 PM
swannies1983 (Dan)
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Thanks for the suggestions guys. I will try imaging without the LPS next time. If it really is the problem, hopefully it's only an issue with bright stars. Mind you, I didn't have this issue when imaging with my 8" Newt. Maybe because of the different setup. I use this adapter with the current setup and the LPS screws on the end. When imaging with the Newt, this is what I had to do i.e. needed a step down ring for the filter to screw into. LPS is much closer to the sensor when using the Newt.
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Old 11-12-2012, 12:33 PM
swannies1983 (Dan)
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Just out of curiosity, is there anyway to remove the reflection in PS?
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Old 11-12-2012, 12:58 PM
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Moon (James)
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Quote:
Just out of curiosity, is there anyway to remove the reflection in PS?
Content aware fill and then the healing brush. But it's cheating, so don't do it! :-)
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Old 11-12-2012, 01:05 PM
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Here's why you shouldn't go overboard with content aware fill
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Old 11-12-2012, 02:33 PM
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Here's why you shouldn't go overboard with content aware fill
LOL

Alnitak is the bane of this region of the sky.
I say embrace the halo.
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Old 11-12-2012, 02:35 PM
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Warning, the photoshop police might be watching
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Old 12-12-2012, 11:04 AM
swannies1983 (Dan)
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Very funny!

It seems CS3 doesn't have the content aware option. I guess the reflection isn't a major problem but I guess it's all subjective. I could do a few curves on selective regions to see if I can blend it in.
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Old 15-12-2012, 06:07 AM
swannies1983 (Dan)
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Just thinking out aloud, but did I really get less reflections with the Newt setup because the LPS filter was closer to the sensor? The body mounted version posted in the classified section has me thinking if this would be a better option as the filter will sit right next to the sensor. Also, this would be a better option if I do wide view imaging with canon lens. I have tried using my current 48mm LPS filter with a step down ring on my canon lens but it produces significant vignetting when using the shorter focal lengths.
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