Here is my first stab at Rho Ophiuchi.
Had only a few clear hours between darkness and fog to get situated, but I am quite happy with the results.
The location was a Bortle 2/3 with excellent field of view. I lost a fair number of subs to the exceptional number of fireflies but am happy with the result.


Pentax K3ii with astrotracer . Rokinon 135mm @f/3.2 ISO800 and 30s.
21 lights plus 6 darks aligned in Sequator (HDR =on) and worked up in Lightroom.

I'm still learning the astro post processing- this one is pretty complex with trying to get a good dust lanes that don't look overcooked and still getting the magenta and blue nebula look. I'm going to keep working it up a few different ways, the bones for a good image are certainly there. Someday, I'll have an educated post processing approach rather than what feels like button mashing.

Haha! Firefly pollution - first time I've heard that :-) Looks great. I have some images I have to process - hope it works out as well as yours.

Great result! You can use the Rokinon wide open at f/2.0, it is that sharp. Have a look at my picture of comet wirtanen with the Pleiades in this group's pictures. It's very close to being the full frame.

Have a look at Pete_XL threads in this group he is very generous about his workflow.

That's really nice for only a little over ten minutes total exposure.

SunnyV
I like the 135mm a lot. Sharp across the board (it even resolves the Galilean moons), but I had flare issues with Antares and Jupiter wide open. Still had them at f/3.2 but it was a balancing act between aperture, concern about keeping ISO dynamic range for the Rho O nebula (should I have been concerned?), flare, and minimizing the risk of lost subs due to the fireflies and high clouds!


Single slightly processed frame with a firefly photobomb

I was trying to stick with one setting so I had the most to work for stack processing, even thought I was convinced that there's probably a better combination. must... resist...temptation....tinker...lose time.

Do you have a favorite setting combo for the 135 and astro?

30 s astrotracer, iso 800 and f/2.0 is what I use. Dynamic range and color rendition tend to go down as you increase iso so I never go above 800 as a general rule. I don't mind so much the flares from bright stars The image below was done at f/2.0. I prefer getting the most signal available in the short time the astrotracer allows good tracking. On a good equatorial mount, I would probably do 3 to 6 min subs with iso 400 and lens closed at f/2.8.