[Theme] Night sky shots

[ColinM]

I came across this interesting video of the moons Io and Europa passing by Jupiter, as seen by Cassini Spacecraft

It was in the "Physics + Astronomy" group on Facebook, so I can't find the original source of the video but here's the FB link

https://fb.watch/rTqZBJ76Pq/

[Øivind Tøien]

North America and Pelican Nebulas (NGC7000 and IC5070) in Cygnus from last night, my first deep space capture session of the season and the first with the 500PF on Z8 in FX mode, using a front aperture (82mm step down ring) of f/6.1. Stack of 95% best of 112 light frames at ISO 1600 after disposing 8 frames with subpar tracking, 122 darks, 45 flats (1/2 sec exposures with EL panel) and 138 bias frames. Stacked in both Sequator and Deep Space Stacker (DSS), then combined the two CNX2 edits in Sequator for final edit in CNX2. The histogram was 1/4 from the left side. I discovered that my off-brand EP-5 adapter was not recognized as compatible by the Z8 so regular batteries had to be used for power. DSS complained about the Z8 files, but nevertheless processed them although the colors did not come out optimally, but without any color ring artifacts. Halos around medium strong stars might have been due to limited  transparency of the air. This is one of the more intense hydrogen-alpha emitting regions in the milky way, and shows up nicely even with an unmodified body. (Open in new tab and click for larger version.)

[Ashlandish]

Øivind, that image, for me, is wonderful.

[Øivind Tøien]

Thanks, Tim. It is a very beautiful region of space.

[Nasos Kosmas]

Excellent shot Oivid so much dense of stars I can’t imagine!

[golunvolo]

Impressive. It ses unreal.

  Thanks for sharing it

[Akira]

As always, impressive result, Øivind!  Thank you for sharing.  Deneb should be just outside on the right of the frame.

[Øivind Tøien]

Thanks Nasos, Paco and Akira.
Yes, the three brighter stars in the Cygnus constellation, Deneb, Sadr and Aljanah forms a nice landmark in the night sky to navigate by and make framing easy (Stellarium screen shot).

[Thomas Stellwag]

Øivind, this is a extremly good picture, which I like very much.  Reading about your steps to get it is interesting as well. Thanks for sharing

[Øivind Tøien]

Thanks Thomas for your kind words. My processing of deep space images has much to be desired, but I am pretty pleased with the final result in this case considering it is a first test of 3 new components (the geared head I am now using on the tracker being the third) and at Bortle 7 light pollution at my cabin. Also the full frame sensor is more forgiving of small tracking errors. The added weight really taxed my simple SkyTracker Classic.

[Ian Watson]

My processing of deep space images has much to be desired

Then I cannot wait to see what you can do with more practice!

Thank you for sharing, Øivind. It is delightful.

[Øivind Tøien]

Thanks for the enthusiastic comment, Ian.

[Øivind Tøien]

The next night I imaged the Veil Nebula which is located below the Aljanah star in the screen shot above and is the remnant of an enormous supernowa explosion stretching out though a vaste amount of space. This is a very star rich region and tend to obscure the Veil Nebula unless a processing is aimed to subdue the stars. I used the star-shrinking tool in the demo version StarTools for this. Same equipment as above except that the lens was the 300mm f/4 PF used with a front aperture of f/4.5. I only got in 76 min integration time as I troubled a bit with framing, but it will have to do for now, Stacked in Sequator, stretched in CNX2.

[Hugh_3170]

Øivind, you are getting very good at these images.

The Z8 and your two PF lenses are being put to good use.

I take it that when you refer to a "front aperture", that the regular aperture is fully open and you have a circular aperture or mask attached to the filter holder?  Is this to improve the masking out of stray light or to reduce some other optical issue encountered in astrophotography?

The next night I imaged the Veil Nebula which is located below the Aljanah star in the screen shot above and is the remnant of an enormous supernowa explosion stretching out though a vaste amount of space. This is a very star rich region and tend to obscure the Veil Nebula unless a processing is aimed to subdue the stars. I used the star-shrinking tool in the demo version StarTools for this. Same equipment as above except that the lens was the 300mm f/4 PF used with a front aperture of f/4.5. I only got in 76 min integration time as I troubled a bit with framing, but it will have to do for now, Stacked in Sequator, stretched in CNX2.

[Øivind Tøien]

Thanks Hugh, you are correct. The front aperture is a step down ring to create an even round aperture, with the native aperture kept wide open. This is to remove diffraction patterns induced by mechanical vignetting caused lens internals like focusing rails to get rounder stars without irregular diffraction patterns, or star burst patterns from aperture blades.