strange stars

[Dave2292]

Hello again, in this picture i have just uploaded there is a weird artifact around the stars, more evident on the brighter ones. i have read a lot online that it could be lens pinch or the cold causing it to pinch, i have been using the scope through the summer and it did not do it then.

can someone confirm what this is for me please? 

the scope is an explore scientific ed 80

thanks for any help.

[Dave2292]

I'm bumping this thread, hope nobody minds, attached another picture. Apparently this is normal according to bresser uk. I have seen pictures taken with this scope without these reflector looking spikes. 

I'm hoping someone has experienced this before and has an answer for me. 

Thanks

[randomic]

I don't know what causes this but I have seen it in other photos. For example: 

 

Although in Olly's picture it appears to have some radial symmetry around the field edges.

I've also seen a similar thing appearing as well as the diffraction spikes from Newtonian vanes but I can't find an example right now.

What do defocussed stars look like? Maybe there's a clue in there.

[Dave2292]

3 minutes ago, randomic said:

I don't know what causes this but I have seen it in other photos. For example: 

 

Although in Olly's picture it appears to have some radial symmetry around the field edges.

I've also seen a similar thing appearing as well as the diffraction spikes from Newtonian vanes but I can't find an example right now.

What do defocussed stars look like? Maybe there's a clue in there.

When I tried M45 it totally ruined the dust around the stars and wasn't salvageable. 

Just waiting on a clear night to look, been pretty bad weather recently. 

[fifeskies]

This is possibly the lens clips intruding into the light path. It is usually only a problem with the very brightest of stars.

Are you using any field flattener or reducer with your scope , these can sometimes help.

 

Sadly it's not uncommon even on fairly expensive scopes.

It tends to become more of an issue the longer you expose the single sub for.

 

Post processing can help to reduce these effects but it takes a bit of effort.

 

 

 

[alacant]

Hi

Isn't this due to the spacers between the lenses? The OP mentioned seasonal differences. Expansion and contraction perhaps? Can the lens cell be adjusted tighter/looser?

Cheers

[randomic]

Just seen this thread, maybe it's the same for you?