Unidentified blobs! Help please :)

[Adreneline]

Hi Everyone,

I set myself up to image M81-M82 the other night with a view to hitting it with everything I've got, namely, the Atik414ex-osc/ED80DS and the Atik428ex-mono/WO-ZS71 (LRGB + Ha) followed up by a widefield view using the Canon 70D on the ED80DS. The Atik images turned out very well and have combined as well as my processing will allow. The images using the 70D contain a number of 'black blobs' that don't look like dust bunnies. There was no evidence of any such anomalies when the 414 was on the OTA - these only appear on the 70D images.

I've thoroughly inspected the 70D as best I can and the end of the R/F and can see no evidence of dust or anything else. If anyone can shed any light on what might have caused them hopefully I can avoid a repeat in the future.

The other odd thing was I had used the 70D to image M31 earlier the same evening at a range of exposure times all at 800iso and there is no evidence of any anomalies on any of the images.

The flats were taken early the following morning (it was just too late when I finished) but the image train was exactly as per the previous evening, nothinh had been touched - the flats do not contain any evidence of the 'blobs' so are of no use for correcting the problem.

This was the combined result from the 414 24x300s, and 428 12x180s of LRGB followed by 12x600s of Ha, which I had hoped to try to combine with the 70D widefield.

Thank you for looking.

Adrian

 

[Spikey]

Ice or water droplets are the likely candidates.

[Adreneline]

22 minutes ago, Spikey said:

Ice or water droplets are the likely candidates.

Well I did wonder if that might be the case. I need to inspect lens surfaces carefully to see if I can see any evidence of evaporation deposits. I had a spider take up residence one night but it didn't look like this!

Thanks for your help.

[RichM63]

Your 'blobs' seem to have depth and look to be dark reddish liquid.

Check that you have not been 'shot'!

[Adreneline]

14 minutes ago, RichM63 said:

Check that you have not been 'shot'!

Haha! Where should I look first? Between the eyes? 

Have to say I have taken several direct hits to the wallet of late. Could it be that?

[Spikey]

50 minutes ago, Adreneline said:

Well I did wonder if that might be the case. I need to inspect lens surfaces carefully to see if I can see any evidence of evaporation deposits. I had a spider take up residence one night but it didn't look like this!

Thanks for your help.

It looks more like water to me. Ice tends to be a bit more angular or just covers the whole thing ! I've suffered from water drops and CCD icing so it does look familiar