an odd dark image

[PaulR1]

Hey folks

so I did some imaging the other night . that all went ok , did my darks and 4 images like this showed up :

This conincided with me turning on the kitchen light to make a cuppa. Light had been off when I did the light subs .

Cover was on scope which is a skywatcher 200PDS and the back of the scope was facing the kitchen about 15 metres away but not direcly but off to the left by about 5 metres .

Anyone have a guess or know where this light on the image found its way in ?

 

[glowingturnip]

it's light-spill round the base of the tube, I get the same with my 200PDS, took me a while to figure out what it was.

I solved it for me by getting a square of black-out-blind material off amazon, and then when I've done collimating i wrap it round the base and hold it in place with a bungee cord of the right length.

 

[spillage]

its leaking in from around the primary mirror. Put your face over the end of the scope in the daytime and look down the tube, you will see lots of light leaking in.

 

Mark.

[PaulR1]

aha ! , thanks guys , if light is leaking in there then its probably not a bad idea to seal it off anyway when doing any kind of image .