donought stars

[Atacamallama]

The attached is 20 x 7 minutes frames + 5 darks, + 60 four minute frames + 13 darks. Meade LX10, 6.3 focal reducer, canon 1000d modded, EQ6 mount, guided.

What concerns me are the donought style stars (some of them have come out as rings with dark centres...). any input on what has happened here or how they could be corrected?

TIA

[Zakalwe]

Are you using DSS? If so, go into Cosmetics in Stacking Parameters and disable the "Detect and Clean Hot Pixels"

[brianb]

Most likely cause of "donut" shaped stars with a reflector (or Mak or SCT) is incorrect focus.

[FraserClarke]

Do you see this in individual subs or not??

That will distinguish between focus problems (doughnuts in individual subs too) or stacking problems (stars will be OK in subs images)

[Zakalwe]

I had exactly the same problem, and it was the Hot Pixel correction in DSS. It looked exactly like the effect that the OP is showing.

[Atacamallama]

thanks for the input... I'm tending to the Hot Pixel Correction theory:

There does not seem to be such an effect in the subs

The friend with whom I collected the data has not had the same effect, having done his own stacking.

Shall restack over the W/e and see how I go...

BTW Zakalwe how do you get the GIF to work on your avatar, when I upload a gif it only displays the first frame....?

[Zakalwe]

thanks for the input... I'm tending to the Hot Pixel Correction theory:

There does not seem to be such an effect in the subs

The friend with whom I collected the data has not had the same effect, having done his own stacking.

Shall restack over the W/e and see how I go...

BTW Zakalwe how do you get the GIF to work on your avatar, when I upload a gif it only displays the first frame....?

Hope it gets sorted:icon_salut:

The avatar? The gif has to be below a certain size...100Kb IIRC. I used some web-based graphics thingy to resize the gif.

[Atacamallama]

Having restacked I can now confirm it was the DSS settings. Only problem is that having restacked and starting from a better image I can't remember what I did to bring out all that detail and colours in this picture and quite reproduce it....

[Zakalwe]

Having restacked I can now confirm it was the DSS settings. Only problem is that having restacked and starting from a better image I can't remember what I did to bring out all that detail and colours in this picture and quite reproduce it....

in the RGB section after stacking, align the RGB channels by clicking on the middle triangle under each slider. Use the arrow keys to align them.

Then go to Luminosity. Select the bottom slider in Mid-Tone. Tweak it left or right to brighten/darken. Don't touch anything else as you can easily clip the data. Then go to Saturation, and give it +10%~ (not too much or you can get loads of noise).

Save the picture as a 16 bit TIFF, applying the changes, and then open in PS for tweaking with Curves.

[Atacamallama]

I'm familiar with that procedure, though have not applied it recently. For some reason dss is only working on my netbook, this means the screen is not big enough to access all the controls for processing.... I usually go straight into PS