Venus conjunction with jupiter and a new Thorlabs filter for venus

hope you've all enjoyed the conjunction of jupiter and venus after sunset.  here's a cellphone shot from my front yard:  

venus above jupiter
6/9/2026 8:48 pm

i've been taking the opportunity to point the bigger scope at venus with some success, catching cloud structure in ultraviolet light:  

Venus UV-IR
6/13/26
used the Baader UV for this

Venus UV
6/13/2026 03:33 UTC
cloud structure visible

Venus IR
6/13/26 04:07 UTC
partially illuminated disk without cloud  structure

Thorlabs ultraviolet filter:

i was informed that the Thorlabs UV filter (bandwidth 380-420 nm) is better than typical filters such as the baader U-filter for my system as the coatings on SCT scopes block much of the UV light in the range of the  U-filter.  i've been trying to capture images with this filter for the past year with no success.  i've dispensed with the barlow, tried earlier and later in the day...nothing but a white disk.  Having tried 2 days in a row with no contrast, i decided to run a comparison between the two...and voila i detect cloud structure with both filters!

i guess the take home is that you need to keep firing away for good atmospheric conditions on both earth and venus.  

Comparison below:

Baader U filter
320-380 nm
average of 2 nine minute captures
details below

Thorlabs UV filter 
380-420 nm
average of 2 nine minute captures
details below

My impression is that the contrast is better with the Baader filter, but the image is more blurry.  The Baader filter required 10 times the exposure as the Thorlabs (10 ms vs 1 ms) likely making the latter more effective at "freezing" seeing, giving a sharper image.  Now it's time to get out the Barlow where the transmission difference will be a more significant factor.  

Note, the Thorlabs filter came in an unconventional size, requiring a separate order of an adapter, so be sure and speak with someone about the appropriate adapter if ordering.  

image details:

East Bluff, CA

wide field Samsung galaxy S22 ultra

6/9/2026 8:48 pm

venus

6/13/26 03:15-04:07 UTC

camera ZWO ASI 290MM 

filters: Baader IR pass "685", Baader U-filter bw 320-380 nm, Thorlabs UV filter 380-420 nm

celestron 11" Edge HD, no barlow

firecapture

autstakkert (best 10%)

biggsky

photoshop

UV 350 nm 

03:33.5 UTC

20:33.5 local

alt 24 deg

Duration=540.004s

FPS (avg.)=91

Shutter=10.80ms

Gain=351 (58%)

Histogramm=71%

UV 350 nm 

03:43 UTC

20:43 local

alt 22 deg

Duration=540.000s

FPS (avg.)=67

Shutter=14.80ms

Gain=351 (58%)

Histogramm=91%

UV 400 nm

03:15 UTC

20:15 local

alt 28 deg

Duration=540.004s

FPS (avg.)=451

Shutter=1.022ms

Gain=351 (58%)

Histogramm=78%

UV 400 nm

03:58.3 UTC

20:58.3 local

Alt 18 deg

Duration=539.989s

FPS (avg.)=451

Shutter=1.818ms

Gain=351 (58%)

Histogramm=85%

IR 685 nm

(IR image above)

04:07.4 UTC

20:07.4 local

alt 17 deg

Duration=180.005s

FPS (avg.)=451

Shutter=0.119ms

Gain=306 (51%)

Jupiter International Observing Campaign entries.

Here are some of my better entries, more details below.

Where's Waldo:

can you find the great red spot in this image?

hint: look at the stuff next to it in the next image.

Best great red spot:

Jupiter with great red spot
the great red spot is noticeably small this year
bonus ganymede transit to the right

OK here's the first image again (below). the GRS is perfectly on edge, right side, just below the southern equatorial belt (lower brown band).  there's a hint of red right on the rim followed by the trailing turbulence seen to the left of the great red spot in the image above.  this is the great red spot rotating away from us.  

sharpest image:

The Association of Lunar and Planetary Observers (of course i'm a member) asked jupiter observers to participate in an international observing campaign to coordinate with observations from the 

 James Webb Space Telescope (JWST) complemented by professional imaging through Juno’s Perijove 81 on February 25.

"Because both JWST and Juno observe Jupiter only intermittently, amateur contributions are important. High quality ground based images provide the continuous coverage needed to track rapidly evolving atmospheric features and place spacecraft and space telescope data in broader context. Even modest backyard telescopes can supply scientifically valuable information when paired with careful documentation"

so i went crazing imaging every night from Feb 20th to 25th, good seeing or bad, even shooting through light clouds...processing as fast as i could, including image annotations with jovian coordinates measured in win jupos.  

for those who are interested they've extended the project through the end of March if anyone's interested.  

needless to say, it was a lot of work. annotated images below

Methane filter on great red spot:

lunar eclipse from the big easy 3/3/26

got up at a a silly hour to catch the lunar eclipse while at a meeting in New Orleans.

final sliver of direct sunlight

the view to the eclipse was across town. so i went scouting the night before.  it looked like it might line up along the streets a la stonehenge, but my phone compass wasn't that accurate.  so i looked for height.  none of the tall hotels would let me in at that hour, but i found a relatively tall parking garage with a view to the west:

Lunar eclipse over WWII museum
New Orleans Louisiana
approximately 5 AM local

After all that i walked back to my hotel to find a perfect framing right out front

NOLA-henge lunar eclipse
3/3/23 5:30 AM local

image details:
samsung galaxy S22 ultra

2/28/26 planetary parade

got so many inquiries regarding the 2/28/26 planetary parade, i decided to give it a shot.

pretty much a bust, but i got some cool sunset god-rays with my cellphone

venus visible above god-rays
saturn was barely visible later, but not captured in image
not seen: mercury, neptune, uranus

looking up for the moon

couldn't resist pointing the big scope at nearby jupiter with bonus great red spot and transiting moon callisto

Jupiter with bonus great red spot and callisto transit

another jupiter 2/3/26

got home to see a halo of light around the moon shining through fog.  knowing fog to be a harbinger of good seeing, i set up the scope, preparing for the disappointment of a total fog out, but hoping for the best.  

to my chagrin, by the time i set up the scope, the sky had completely cleared and the seeing began to degrade, but not terribly.  

Here it is with a methane filter which isn't showing much:

Just for fun, here it is in methane (red) + RGB:

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

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: