lindaw12•1mo agoMost Upvoted

Heard a pro astrophotographer say you should always dither, and I finally tried it on my Orion Nebula shot

I was watching a YouTube stream from a guy who does deep sky imaging, and he said dithering between frames makes stacking way cleaner because it gets rid of that fixed pattern noise from the sensor. I always thought it was overkill for my setup. Last clear night I set my mount to dither by 10 pixels between each 3 minute exposure on M42. After stacking 60 frames in DSS, the background was way smoother than any of my previous tries. No more walking noise or that weird grid pattern. Has anyone else seen a big jump in quality after adding dithering to their workflow?

2 comments

2 Comments

paige_west1mo ago

That 10 pixel dither on my CGEM mount was a game changer for me too... I was getting this horrible fixed pattern noise on my Triangulum Galaxy shots, little horizontal lines that wouldn't go away no matter how many dark frames I took. First time I dither in NINA, set it to 8 pixels with a 3 second settle time, and after stacking 40 subs in DSS the background just looked clean like glass. No more tiny grid lines, no walking noise at all... I actually had to double check I hadn't accidentally applied some noise reduction. Now I won't image without it, even on bright targets where I thought it wouldn't matter.

clairem3829d ago

and what really sold me was watching a talk from that guy at Astro Imaging Channel, he broke down how dithering does more than just kill walking noise. The fixed pattern stuff on CMOS sensors is way more stubborn than people think, especially with those newer chips that have that weird amp glow in corners. He showed side by side comparisons with like 2 pixel dither vs 10 pixel and the difference was night and day on the faint dust lanes. Even on bright targets like Orion or M31 I've noticed my stars come out rounder with dithering, seems like it smooths out the tracking errors too. You're absolutely right about the dark frames not fixing it, darks only handle the thermal noise, they can't touch that readout pattern. I've started dithering every single target now, even if I'm just doing a quick 20 minute run on the moon or planets, just set it and forget it.