I have been taking fotos of moon w/ my Sony A6300 & the 200-600 Sony telly. As a starting point for nitely fotos it would be most helpful if i could calculate exposure from data of moon's apparent magnitude published for a specific date & time. The closest i found to this is a calculation of smallest magnitude star visible. The formula is:

(log¹⁰D*5)+7 = minimum visible magnitude. ¹⁰ is base 10log, D is aperture for Sony 200-600 = 9.5cm

and

EV= log²(N²/t) where log² is base 2log, but N² is N*N & t is time.
While i once passed a course in diffyQ at 87 my algebra skills have dropped down a hole in my Swiss cheese brain & i am at a loss to combine these two equations. I would prefer to calculate the shutter speed, t for a given f-stop & ISO. To pick some numbers say, f8.0 at ISO 100 for the Sony 200-600 telly w/ D = 9.5cm.
Or if there are other ways to calculate it please show me how. Trial & error are becoming frustrating as is using spot meter on hilites and dialing in minus exposure compensation.

TIA

Thank you all for giving a hoot!

Yes eastern id'ed from mournful call. Foto from my apple orchard just 10' west of Fort Collins, CO.

Thank you. I had the A6300 on M-rate multiple exposure so I caught only this & one other almost closed mouth of the yawn

1st time i have seen an owl yawn.
Foto is from Xfr Sony A6300 to my Moto G Stylus SmartFon, but in original enlarged shos pinkish lower bill (& tongue?)

The other morning the waning moon was a thin crescent, ~3% llluminated @ -1.7 magnitude. It would have been helpful to calculate what Exposure Value that is to give a starting point for proper exposure.
Also last nite Jupiter was at -2.8 while it Galilean moons varied from 4.8 to 5.9. How can the range in EV for this range in magnitudes be computed? TIA

Have you seen this video? Link2-
https://youtu.be/5DSz5kZbXVY
Make plate to stabilize heavy lens

In early spring hike down from south rim, camp at bottom and hike up to north rim which can be deep in snow. Also waterfalls 1-2 feet wide cascading hundreds of feet. Sadly slides have become mildewed due to my neglect in Florida. And I took a number of infrared 4x5s , but left the holders in the truck and the heat exposed them to total black, DUH what was I thinking?

Updated laser pointer adding mini-ballhead to lock it in position. Good enuf to center Mars in Sony A6300 monitor.

Laser to Mars

(Download)

My apology if you get two of these msgs.
They said, "It's your birthday, 'Here's HAPPYS to Ya'" a day late. I rigged a Z-Bolt laser to a mini-ballhead on a hot shoe ¼-20 screw to slide in the flash shoe atop my Sony A 6300 to use as a pointer. Works good enuf. My apilogy if I already sent you about it, buTT @ 87 finding my glasses is a daily task. As you can see it points a bit high, sufficient to align Mars (center, Aldebaran & Pleiades. Do you know the relationship between the magnitude of say Sirius @-1.2 and Expsoure Value ? I am thinking it is a way to estimate ISO + f stop & shutter for my Sony 200-6000 f5.6-6.3 telly lens. Started up the steep curve learning Siril to stretch & stack, meanwhile the moon is my friendliest astro target. Here in Florida clouds are hindrance. Good luck w/ 7Sisters fotos.
Oooops I see I did send one laser fitting note. Update is using mini-ballhead.

Pleiades are faint @ lower right

Try again w/ sourdo foto.

Apology if this is multiple posting, buTT I get multiple "Website not available error" so try, try again. Here's sourdo baking. Food toasted w/ homemade apricot jam!

Err msg can't load sourdo foro

You asked about the laser pointer. I found this foto of crescent moon where I used the laser to line up the Sony 100-600mm lens on the A6300 camera (1.5x crop factor 900mm focal length) for this shot. I think I aimed for center of terminator. Camera on tripod, legs tied together to convert it to a monopod. I usually line up the greendot on the center vertical line in the viewfinder and then rock the camera forward & back until object is centered and then a series of 9 shots bracketed using Auto ISO from 100-25600. I think this was shot at 1/60"/f6.3, EV -3, (so ISO 400?). If EXIF data is attached it has all that.
I finally got Siril to import my Sony .arw RAW files. It outputs them as FITS format. May not get to processing them further until the weekend. It looks like Siril and GIMP or digiKam will be sufficient to get to a final image. Found some tutorials on UTube.

I made it from AmZ supplied parts & Z-bolt laser that was discontinued and a real bargain @ $30. There is post from SonnyE 27 Dec 20 @ 19:19 w/ his good experience w/ this laser and I have had no problems @ 300mm, tho at 900mm foto tripod screws everything up as I tighten screws, but that is 2°40' AofV. I can send more fotos and detail if you like?Right now need to get sourdo in oven for this week's loaf of bread!

Thank you much. I will give it all a try. Yup, SER is video. I took 4k video of Saturn Jupiter conjunction 21 Dec 20. Eventually will see if I can get it into Siril, but try first your advice w/ moon & same nite as video of Sat-Jup.
Are you familiar w/ KStars?

https://edu.kde.org/kstars/

I find it easier to use than Stellarium & eventually if I ever get back ro Colorado use it as GoTo app for my Celestron 5" telescope.