Astro Photo Question (trying this forum)...

Started Sep 28, 2022 | Questions thread
just Tony
just Tony Veteran Member • Posts: 4,628
Re: Astro Photo Question (trying this forum)...
1

John Retsal wrote:

[ I asked this over on the Astrophotography forum and got zero replies ]

I'm going to try my hand at some wide-field Milky Way photography.

You have a very short time window at this time of year, and you will want to have a fairly low horizon to the South and Southwest.

Camera is Nikon Z6II with the Z 14-30 f/4 lens.

It’s going to be challenging to set the focus precisely at 14mm. Very little light gets through an entrance pupil of 14/4 = 3.5mm diameter. Use the star Vega, the brightest star nearly straight up at this time of year early at night, and examine your test shots at max magnification. When you see tons of dim stars you have it.

Manual focus mode, manual exposure and VR Off are your friends.

Location has Bortle 2 skies (for those who know what that means), so pretty dark.

Nice!

I'd be shooting at 14mm and maybe 20mm, wide open at f/4 tripod mounted, no tracking and VR off.

I'm pretty sure I need to keep my exposure times (per the NPF rule) to around 11 sec for 14mm and 8 sec for 20mm in order to have no trailing visible.

Also do some exposures a bit longer. You will be using a high ISO because of f/4 (even f/2 is hard to live with on a fixed mount) which will impose a very strict limit on how large you want to display the image. The noise will impair image quality more significantly than a tiny hint of trailing.

Take a lot of shots and stack them with sequator (Windows) or Starry Sky Stacker (Mac) to mitigate the noise. Sequator can separately stack the sky and foregrounds, maybe SSS can as well.

Noise decreases as the square root of the number of stacked frames. 4 will get you 1/2x, 9 will get you 1/3x, 16 will get you 1/4x.

You will get satellites and I believe that stacking programs have the option to eliminate them. Satellites are at their worst during twilight and still so after the end of twilight, but least bad near midnight.

What I'm unsure about are other settings such as ISO (taking into consideration the camera's ISO Invariance) and white balance.

Try in advance even on light polluted skies (shorter exposures of course). Only you can judge what you like. You might go with something around 3000-4000.

If you had a tracker I’d recommend ISO 800 with exposures running to 2 or 3 minutes.

Use Daylight white balance.

And a bonus question, is there any advantage in shooting in b/w in terms of the quality of the images?

Personal preference regarding the look is as far as you need to consider it.

Don’t fail to examine shots while you’re out there, and adjust if necessary if you see issues.

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Wag more; bark less.

 just Tony's gear list:just Tony's gear list
Sony RX100 VA Nikon Z7 Fujifilm GFX 100S Nikon Z9
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