Any idea what this 'splodge' is ??

[Skipper Billy]

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.

 

 

 

 

[Oddsocks]

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!

[Skipper Billy]

This is the spoiled area - highlighted..

[Tommohawk]

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!

 

[des anderson]

Can`t help with "thing" but WHAT an image.....Just mind blowing.

Des

[VilleM]

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

[Skipper Billy]

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 

[alacant]

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.

[Skipper Billy]

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

 

[johnrt]

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.

[Tommohawk]

Agreed it looks like reflection, but would the position vary with a reflection?

[sharkmelley]

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

[Tommohawk]

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?

[ollypenrice]

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