Black Flecks in data

[Earl]

Any idea what these are?

this is from acalibrated set of OIII subs with a total time of 1 hr 10 mins

[Davey-T]

Looks like noise ? have you got a bigger picture ?

Dave

[swag72]

I agree with you Dave - At this size it looks like noise to me.

Is it all over the image Earl or just in certain places? Is it on your uncalibrated OIII subs?

[Earl]

this is the full image, calibrated and basic stretch

https://dl.dropboxusercontent.com/u/43788925/oiii.jpg

[Earl]

and this is a single oncalibrated sub

https://dl.dropboxusercontent.com/u/43788925/OIII_001.jpg

[Spikey]

I'd tend to agree. It certainly looks like noise. Have you taken any darks?

[Oddsocks]

Your single sub looks normal to me, noise level is what I expect to see in my NB subs.

I wonder what combine method you used? Sigma Clip or Median / Average should take out the noise from the final stacked image but a straight summing enhances the background noise similar to your posted image.

[Earl]

i just use the PI prepocessing scipt, I do need more subs though ill get them i think first.... next year maybe HA