Here is another astrophoto. This time Antares and the M4 globular cluster and the star Alniyat on the right side of the frame.
Specific Feedback Requested
I was not going to post this photo because I could understand what that strange glow was. I could not tell if it was really a nebular or dust glow or a camera artifact. But @DianeMiller suggested this combination of stellar entities and I did make just such a photo.
So I would like to ask, those of you who do know astrophotography is that glow natural or a camera artifact?
Technical Details
Nikon D850, Nikon 400mm f/5.6, at f5.6, 30 sec, ISO 6400, tracked using a SkyGuider Pro tracker. Photographed as a TIFF and processed in PS CS6
Youssef, I can’t answer your question. I just want to say that I really like that spiral cluster. Is that M4? It seems so delicate. That cluster alone deserves a long lens ( maybe with a telescope) to get a close-up!
@Mark_Muller yes it is M4. The 400mm is my longest lens. I could only hope to have a good telescope to work off of, one that has a good tracking mount.
The glow is heavy vignetting from the lens… This part of the sky has a tremendous amount of color that can be brought out stacking images… even 30 second images.
With the tracker, if you used a lighter wide angle lens in this part of the sky you should be a able to track a couple minutes at lower iso with just semi good alignment and get all of Scorpius in one frame.
@Dan_Kearl are you sure? That lens has never exhibited any vignetting and I use it often. Please take a look at the next photo I am posting with the same lens. No vignetting is apparent, unless I am not understanding how this lens works in dark sky imaging.
That’s a wonderful capture of M4 with wonderful detail! Is this the full frame? I don’t think this is completely vignetting. Maybe a little, but I think you have captured some of the nebulosity in this region.
Vignetting is a problem with very dim astro subjects such as nebulae because of the large increase in contrast with the processing, but it should be symmetrical at the frame edges/corners. In that case, people shoot “flat” frames to cancel out the effect. These are used in complex processing with specialized software, along with “bias” and “dark” frames to correct for forms of noise. That sort of processing, with hours of total acquisition time, is needed to bring out the dim nebulosity that this region has.
I see a mottled appearance in the lighter BG areas that has sadly been typical of my attempts to bring up shadow detail with a DSLR for night scenes such as the Milky Way, and it has varied slightly with 3 different cameras (Canon 7D2, 1DX2 and 5D4). Dan has solved the problem by switching to a specially designed astro camera.
Somewhere I have the image of the galactic center region that I described in your previous post, framed to show the dust lanes leading to Antares. I don’t find it in the collection I keep for posts here, so I’ll post it separately. It’s not the image I had hoped for at the time, but for now it will have to do.
I’ve decided astro is a bottomless pit for equipment and time and decided to stick with regular subjects.
@Diane_Miller Thank you for your feedback. Perhaps some more detailed work with flat, dark, and light frames will produce something better. I started out in photography photographing the new crescent moon and it seems I have now come full circle back to the night sky. I will dabble in this for a while until I feel I have captured the essence of the sky as seen by my eyes. While I deeply love deep sky images (pun intended) I do not think I will be going down that deep, but who knows.
Yousef, you don’t need to take the leap to all astro to get better results.
Get a telescope. DSLR or Mirrorless can connect with simple adaptor. Most all people who dabble in Astro and get discouraged are trying to shoot with very heavy too complex camera lens.
A 350mm telescope at f5.9 is like $500. It will outperform a camera lens shooting infinity by about 100 times.
You can mount them on your tracker and they are lighter.
Astro cameras will outperform regular cameras easily also but you don’t need to take that step…
Very nice Diane, stars are pinpricks and color is nice.
Wide angle DSLR lens are fine with a nice tracker and processing but anything above 24mm is better with a telescope. Simple also.
Except the Rokinon or Samyang 135 f2 which is a DSLR lens made for Astro and a staple for Astrophographers. It is used with Astro cameras with great results.
Very nice Diane. I am going to have to look into stacking images. Those dust threads point to Antares are great. Looks like I have my work cut out for me.
