First Star Trail (is it noise?)

First attempt with start trails shot on my 7Dmk2 16-35mm approx 100 30 sec exposure stacked using Starstax

what do you think the bright white artifacts?

Thanks guys

Very curious looking. Do the large white spots show up in the individual frames and are they in the same spot across multiple frames? I've never seen noise appear like that. It even appears too big to be hot pixels.
Can you post a single frame from about mid way through the sequence?
I also noticed there are several unevenly spaced gaps in the star trails. Were you using an intervalometer or doing it manually?

I'm also curious if the spots show up in the same location in all the images.
My first thought is sensor dust but part of me thinks they're too big to be dust.

DGStinner wrote in post #17409315
I'm also curious if the spots show up in the same location in all the images.
My first thought is sensor dust but part of me thinks they're too big to be dust.

Dust would show up as dark spots, not light spots.

FYI - Many, many years ago....we are talking about push processing film days, I had a single star trail image of 30 minutes show up with spots very similar to this in the print. It turns out it was caused by fireflys flying around in front of the camera.

Maybe dirt on the lens?

Whatever it is, I like it!

(dew/condensation on your lens?)

Was it snowing ?

My guess is that you have a frame in your stack that doesn't belong there. eg You took a shot at 35mm to see if you were centered on the pole and then zoomed back to do your trails. When you stacked them, you included the zoomed in one.

Steve.

Thanks for the replies... I'll go look closer at the individual shot's... I did remove about 5 or so thru the stack that had planes through the image... thought maybe the gap filling in startstax would fill that....

I'll look again... lens may have been dirt but I did have dew issues after an hour or so worth of shots... I thought I didn't include those in the stack..

Pixel Perfect wrote in post #17410049
Thanks for the replies... ... lens may have been dirt but I did have dew issues after an hour or so worth of shots... I thought I didn't include those in the stack..

As was said, dust would not show up as white dots
But dew drops may be refracting incident light from streetlights or whatever down into the optical train and that would be a good possibility


Dave

As SteveinNz said. Looks to me like a frame slightly out of focus of a different area of sky

that is an interesting thought .... would also account for the dots in front of the trees