3 replies to this topic

[Sp0nG3Bo8]

hi

doing astrophoto for a while but on and off (clear skies only when i work lol )

so i started stacking and i keep hitting a snag: it looks like my darks dont quite "clean up" noise from the sensor of subs. my images look to have grainy lines

 

i am using the ZWO ASI180MM-PRO  at -10deg C 

captured with kstars/ekos under indi driver (remote in my backyard )

stacking with siril 1.2.6

 

this is the result with 30s subs x 20  with 20darks stacked applied to them 90gain and offset 0

( i had other subs at 53 and111 gain 8offset but my fat finger on low battery mouse resulted in absolute cathastrophy)

(only processing applied is calibration (master_dark), registration and stacking  then re-registered (to align ha,sii,oiii stacks) then stacked as a color image and then shrunk 1/2scale in gimp

 

my subs also look this grainy but with amp glow.

 

what do you think USB cable interference or something else ??

 

 

ps:if this is the wrong forum feel free to move it.

Edited by Sp0nG3Bo8, 27 March 2025 - 04:37 AM.

[happylimpet]

Not a cable thing - they eirher work or not - they cant 'corrupt' data like this. Some sensors just seem to do this and often its a function of the gain or even the 'usb traffic' setting chosen.

 

However, there's software that can fix it. Freeware FITSWORK has a function called 'lines to equal values' which easily sorts stuff like this.

 

I had to resize the image, and for some reason it was very dark when i opened it, so ignore that, but you get the idea!

 

 

 

[Mbenj2405]

Are you dithering?

[Sp0nG3Bo8]

well found the culprit ... cabling issue took a dark and no longer grainy with another cable (also separated the cable from the power loom i had made (so that only one bunch went to the scope.

 

will have to redo the setup  :-/ ... with new and probably shorter cabling ... (its either because it was next to power feed or because zwo's flat usb cables are no good lol )

 

i still got to workout the dark frame i took (half of it is more pale than the other half ... possibly cable too long ... darnit gota get new and shorter cable...)

 

 

darks now look like this:

Edited by Sp0nG3Bo8, 27 March 2025 - 06:30 AM.