Starlinked twice

[tornado33]

Hi all. Imaged NGC 253 had the LPS filter in thought Id try that on the galaxy, allows me to shoot a higher ISO and 15 min subs without overexposing. 6 x 15 mins ISO 800.

Also the Skull Nebula NGC 246, 4 x 15 mins ISO 800 with the filter. 10 inch f5.6 Newtonian, off axis hand guided. EOS Ra.

Full size versions here
https://www.astrobin.com/bhucio/?nc=user
https://www.astrobin.com/j2sjgs/?nc=user

Look at all the Starlink trails, imagine when the whole shebang is up there in orbit.
Cheers, Scott

[Saturnine]

Whether it is Starlink trails or other satellites trails, they have spoiled otherwise fine images, NGC 246 is a good catch considering planetary nebs are mostly low surface brightness objects.

[CoolhandJo]

Nice shots . Looks like the Ra is a fine camera

[TommyJ]

The number of artificial objects in the sky will only increase now. In all assumptions, the result should be something like a Dyson sphere. It seems to be beneficial for future generations in the form of extracting energy from the parent planet. But this is a gradual process. And it will completely change astronomy as it stands. And now we are at the stage when there will be more satellites.
I think it is already worth thinking about how to do amateur astronomy with their help.)

[redbeard]

Is it possible to remove the trails in post processing?
Using flats?

Cheers for posting examples.

[jamespierce]

You remove them by stacking many images.


I suspect more shorter subs are in our future. CMOS cameras prefer this, and it will make stacking out transient noise like sats much more efficient. Not sure what it means for 30min narrow band subs thought.

[redbeard]

Cool, cheers.

[multiweb]

Two very tidy shots. Well done. :thumbsup:

[Wilsil]

I am surprised that it wasn't removed during stacking.

[gregbradley]

Looks very good. You can remove satellite trails using the healing brush in Photoshop. Click on the start of the satellite trail then click on the end of the trail and with the right width brush it removes the whole trail.

Greg.

[Placidus]

Two very fine images. Well done.


The way to handle satellite trails is at the time of stacking. A median combine will be pretty well guaranteed to remove satellite trails so long as you have at least 3 subs in the stack, but it is not the most efficient at capturing good photons. We use a "trimmed mean" which is the mean after of a winsorized sample. It requires more subs to work really well, but is very efficient at preserving good photons. It is also great at rejecting cosmic rays (which is I suppose a bit perverse, given that they are real astronomical events coming from the other side of the universe!). We also offset each frame by a few percent of the field width. That helps get rid of a raft of other artifacts including hot pixels, bad columns, and after-images, but is not necessary for rejecting satellites or cosmic rays.

[tornado33]

Thanks all.
IRIS does do median stacking but Ive found the results a bit noisier but if there are more sat trails in images I take I will give it a go
Cheers
Scott

[Nikolas]

Stacking using sigma kappa clipping or its variants gets rid of the satellite trails

[TommyJ]

Сonsidering the plans of only a few American companies and China, the full sky of satellites awaits us soon. And we also add here all those countries and private companies that want to return or enter space. And we get a very long photo processing)

[muletopia]

Scott,Hope you don't mind but I had to try my new software AA7
Semms to have taken out the trails with no damage.
Chris