Try increasing gamma if dark sections aren't distinguished

Try increasing gamma if dark sections aren't distinguished

Saturday, January 31, 2026

Jupiter and Io's shadow

Finally got a clear shot at Jupiter
along with a bonus Io shadow transit:




animation of the tail end of the Io transit:

Io transiting Jupiter

Imaging details:
edited first image using independently stacked Io
had hoped to image jupiter over christmas break, but nothing but rain and clouds.  pristine skies afterwards, but with seeing so poor stars were flashing like fire engine lights.  managed to get one night of not terrible seeing for this capture.  
a few technical difficulties led to gaps in the capture.  
captured a total of 16 sequences.  processed them all in win jupos then photoshop only to realize that it was too long a time span actually degrading the quality of the image.  
then re-did the whole thing with only 9 images.  
tried bigg sky again. the problem was that the seeing wasn't great so had to smaller stacks (excluding 50%) in this situation bigg sky tends to add noise, so i processed luminance only which muted the colors.  the final image above is mostly registax.  
here are full scale animations with the two techniques.  
note that bigg sky requires sharpening before derotation.  so you wind up with sharpening artifacts that are mitigated by stacking after derotation.  
conversely using wavelets, i undersharpen the individual captures avoiding artifacts, then push the sharpening after derotation/stacking when there is less noise (improved signal to noise ratio).  
Bigg Sky

registax

raw stretched stack after derotation
Bigg Sky

registax



Tuesday, January 6, 2026

sun 12/7/2025

the series of sun spots (active regions AR 4296, 4294, 4298) were indeed active, blasting ions at the earth in early December.  i happened to catch them during a day with good seeing (i can't usually discern the "granules" in the white regions so well):  

AR 4296, 4294, 4298
12/7/2025
21:51.6 UTC
Granules are convection cells in the sun's photosphere.  "The rising part of each granule is located in the center, where the plasma is hotter. The outer edges of the granules are darker due to cooler descending plasma" (wikipedia). 

I also captured a series of full disk images in Ha:

Sun Ha Surface
2025-12-07 20:58.3 UTC


Sun Faint Ha prominences
Digital occultation of disk
2025-12-07 2058.9 UTC

Sun 2025-12-07 
Ha composite

Ha composite
difference

Solar surface
Ha vs off band

Sun Ha vs white light


Image details:
close up
Celestron 11" Edge HD
Baader solar film
green filter
unguided solar tracking on celestron CGX

full disk
Lunt 60 PT B1200 single stacked

zwo ASI 174MM
2025-12-07
all 20 second captures full frame
East Bluff, CA
better than usual seeing

close up:
Frames captured=2064
FPS (avg.)=103
Shutter=0.082ms
Gain=325 (81%)

full disk surface Ha:
Frames captured=2610
FPS (avg.)=130
Shutter=0.073ms
Gain=280 (70%)

full disk prominences:
Frames captured=2606
FPS (avg.)=130
Shutter=1.958ms
Gain=280 (70%)

full disk off band:
Frames captured=2609
FPS (avg.)=130
Shutter=0.032ms
Gain=302 (75%)

captured in firecapture
stacked in autostakkert
sharpened in BiggSky or registax
combined/finished in photoshop.  

Processing notes:
for the close up
a zwo green filter gave slightly better contrast compared to luminance (UV/IR block).

i also captured 30 minutes of the full disk in Ha for an animation...there was minimal activity over the course of the animation :(

BiggSky wasn't as good as registax for full disk or proms, but looked better than registax to me for the close up green light image (though slightly over-sharpened). 
raw big sky:

registax: