Skipper Billy Posted November 21, 2016 Share Posted November 21, 2016 I ran all my subs through 'Blink' to quickly see what they looked like and noticed a 'splodge' (circled in the attached images) - each image is one sub of LUM. It jumps about from frame to frame but stays in a small area of the sub - it appears to move at random but not in sequence with the stars so I don't think its dithering causing it. If it was on the sensor then it would stay in the same place ?? Its on all the RGB subs as well so its probably not to do with the filters. The end result in the stacked image is a lilac/purple patch where the splodge has jumped about. I have never seen this before - any ideas ?? If it helps its a SW ED80 with flattener, Atik 460 EX, EFW2 and Baader filters. It was poor seeing and minus 6. Link to comment Share on other sites More sharing options...
Oddsocks Posted November 21, 2016 Share Posted November 21, 2016 Hi Skipper, Because the artefact has a bright ring around it I think its probably a small droplet of condensed water, maybe on the front optic or somewhere in the image chain, I expect it will probably disappear once the scope has dried out, if not I'm wrong! Link to comment Share on other sites More sharing options...
Skipper Billy Posted November 21, 2016 Author Share Posted November 21, 2016 This is the spoiled area - highlighted.. Link to comment Share on other sites More sharing options...
Tommohawk Posted November 21, 2016 Share Posted November 21, 2016 TBH I haven't a clue - but will be interested to know the outcome. You'd think a spot of condensation would be in the same place on all subs? That aside its a very nice shot! Link to comment Share on other sites More sharing options...
des anderson Posted November 21, 2016 Share Posted November 21, 2016 Can`t help with "thing" but WHAT an image.....Just mind blowing. Des Link to comment Share on other sites More sharing options...
VilleM Posted November 21, 2016 Share Posted November 21, 2016 Its a reflection, might be from condensation (water droplet). It might also be caused by anything reflective in the optical chain, street lights, bright star, list is really endless what could have caused it. I would suggest that you take the same photo again, just one sub is enough to see if its still there. Then if it is take another photo of another object. If it disappears is caused by bright stars and you should try to do some DIY baffles on your OTA or longer dew shield if its caused by street lights. -V Link to comment Share on other sites More sharing options...
Skipper Billy Posted November 21, 2016 Author Share Posted November 21, 2016 34 minutes ago, VilleM said: Its a reflection, might be from condensation (water droplet). It might also be caused by anything reflective in the optical chain, street lights, bright star, list is really endless what could have caused it. I would suggest that you take the same photo again, just one sub is enough to see if its still there. Then if it is take another photo of another object. If it disappears is caused by bright stars and you should try to do some DIY baffles on your OTA or longer dew shield if its caused by street lights. Thanks - I wouldn't think its water - it was really cold last night (-6c) unless it was very close to the dew heaters it would have frozen. I will try the same target then something else as you suggest. Definitely not street lights the nearest one is 10 km away Link to comment Share on other sites More sharing options...
alacant Posted November 22, 2016 Share Posted November 22, 2016 Hi. JTOL but I've had similar when I used a field flattener with a filter attached. Did you use a ff maybe? The train was: telescope - filter - ff - t-adapter - dslr. Otherwise duno... HTH. Link to comment Share on other sites More sharing options...
Skipper Billy Posted November 22, 2016 Author Share Posted November 22, 2016 I am using a flattener but I always have and have never had this before - imaging train is scope - ff/fr/M48-T2 - EFW2 - CCD Link to comment Share on other sites More sharing options...
johnrt Posted November 22, 2016 Share Posted November 22, 2016 I think a reflection too, the Pleiades are very bright stars and are likely to show up any defects like this that will stay safely hidden away on most other regular targets. Maybe try pointing at something else very bright, Alnitak next to the horsehead for example, and see if you can replicate it. Link to comment Share on other sites More sharing options...
Tommohawk Posted November 22, 2016 Share Posted November 22, 2016 Agreed it looks like reflection, but would the position vary with a reflection? Link to comment Share on other sites More sharing options...
sharkmelley Posted November 23, 2016 Share Posted November 23, 2016 6 hours ago, Tommohawk said: Agreed it looks like reflection, but would the position vary with a reflection? Because it's a reflection. When the stars move one way the reflection moves the other. Look how it dances with the stars (this is a crop): Mark Link to comment Share on other sites More sharing options...
Tommohawk Posted November 23, 2016 Share Posted November 23, 2016 10 hours ago, sharkmelley said: Because it's a reflection. When the stars move one way the reflection moves the other. Look how it dances with the stars (this is a crop): Mark Give that man a prize! So... maybe its a reflection then? Link to comment Share on other sites More sharing options...
ollypenrice Posted November 23, 2016 Share Posted November 23, 2016 Good demo from Mark. The fix should be easy enough. (Don't throw that data overboard, Skipper!) Just do a short set for each filter with the scope framed significantly far away from the original but still covering the reflection area. The reflection should now be somewhere else. You can use the short set as a patch. I'd shoot the same length of subs but two of each ought to be enough to fix the reflection. Photoshop layers, refelction on top, patch panel underneath, erase the top.) Olly Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.