4 replies to this topic

[sdbirder]

I recently got a PVS-14 L3 WP from Apollo with some pretty nice specs (2570 FOM, 35.7 SNR, 0.3 EBI) and attached it to my Nikon Z8 in front of 35mm and 50mm Z lenses. I also recently got an ITT 3x military magnifier lens from eBay that screws into the PVS-14 and have really been pleased with it so far.

 

Last weekend, I tried some star photos from the city, and the results were pretty mediocre, washed out, and lacking contrast. This was likely due to city lights and haze from being close to the coast (Bortle 7). What ISO do you recommend, and should I reduce the gain for a darker, more contrasty image from the NV for stars? I was able to salvage some of the shots with raw adjustments and image stacking.

 

Looking forward to going to dark skies soon.

 

Thanks in advance.

[Joko]

I recently got a PVS-14 L3 WP from Apollo with some pretty nice specs (2570 FOM, 35.7 SNR, 0.3 EBI) and attached it to my Nikon Z8 in front of 35mm and 50mm Z lenses. I also recently got an ITT 3x military magnifier lens from eBay that screws into the PVS-14 and have really been pleased with it so far.

 

Last weekend, I tried some star photos from the city, and the results were pretty mediocre, washed out, and lacking contrast. This was likely due to city lights and haze from being close to the coast (Bortle 7). What ISO do you recommend, and should I reduce the gain for a darker, more contrasty image from the NV for stars? I was able to salvage some of the shots with raw adjustments and image stacking.

 

Looking forward to going to dark skies soon.

 

Thanks in advance.

Get an IR Pass 685nm filter to have better contrast in light polluted skies.

Edited by Joko, 10 July 2024 - 07:55 AM.

[ytserrof]

Depends on your mount that determines the maximum shutter speed. With longer shutter speeds you can set lower ISOs. For me a 2 sec shutter speed means 800-1600 ISO on my phone.

If you have a decent mount and tracking you should be able to take astonishing pics with your setup. Darker skies help here as well a lot.

[WheezyGod]

If you’re using an iPhone I recommend the Astroshader app which provides alignment/stacking across many photos in that app. If you’re using something else then I’ll let others chime in.

[ButterFly]

Stacking a whole bunch of short exposures is better off in the long run.  The pixels will pick up any spurious emissions in your background, which can be rather bright, just as easily as they will pick up the emissions from the stars.  The loner the shutter is open, the more spurious emissions you get.  A low tube gain helps reduce the spurious emissions.  A filter helps reduce the actual background.  Stacking helps remove the spurious emissions' effects from the stack, particularly with sigma clipping.

 

The iso for your camera really depends on how it processes.  If you can, run a sensor analysis on your chip using Sharpcap.  Try to pick the ISO that affords you the greatest dynamic range.  Take darks at that ISO as well, at around the same temperature as when you did the shoot, at the same exposure times.  If you set your tube gain low enough to avoid lots of spurious emissions, try calibrating with darks using covered tube, but still on at that tube gain.