Try increasing gamma if dark sections aren't distinguished

Try increasing gamma if dark sections aren't distinguished

Wednesday, November 30, 2022

Mars is here, 11/26/22. filter tricks--IR filter with RGB camera

 Mars is here.

The seeing wasn't great this session, so i imaged without a barlow.  I wanted to test out an infrared filter with a color camera which worked perfectly (see details below).

Mars 11/26/22 8:51 UTC
RGB left, IR 850 pass center, IR-RGB composite right

as i was breaking down the gear, i noticed that the stars were no longer twinkling ;) 
broke out the barlow and got less sleep than planned:
Mars 11/26/22 9:26 UTC
single 120 sec capture

Why an infrared (IR) filter works with a color camera:
the color filters in many color cameras pass infrared light.
(which is why you should use an IR blocking filter)
The ZWO 290 MC passes the IR from an 850 nm IR pass filter equally through all color filters.
as a result, you can get a uniform full resolution monochrome IR image when using an IR filter with a color camera.  
just be sure to set the color balance for all filters to neutral (see below).  

Image details:
11/26/22  08:34-09:26 UTC
celestron 11" Edge HD

first set
ZWO ASI 290MC (one shot color camera)
baader IR/UV block filter for RGB images
400 fps, .191 ms, 351 gain, 40% histogram, 120 sec x 4
ZWO IR pass 850 nm for IR images
set green and blue gain to .5 in fire capture for IR
400 fps, .855 ms, 351 gain, 35% histogram, 120 sec x 3

second image
ZWO ASI 290MC (one shot color camera)
baader IR/UV block filter
televue 2x barlow
152 fps, 2.132 ms, gain 291?, histogram 49%, 120 sec
single 120 sec capture

firecapture, autostakkert 5% stacked, winjupos, maxim, photoshop
elevation ~80 degrees
Eastbluff
Southern California

for IR-RGB blend IR was used as red channel and 30% luminance, color rebalanced on white pole structure.  

ref:
IR filter with ZWO camera
https://astronomy-imaging-camera.com/product/1-25-ir-850nm-pass-filter
"just don’t forget to keep the WB_R and WB_B to 50 (no White Balance applied)."
fire capture screen shots:
click for full size

click for full size


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