pitfalls and perils of solar imaging: testing for upcoming solar eclipses

testing my solar imaging:

sun 
9/23/23
baader film filter
single exposure 1/1,000 sec ISO 100, 300 mm f/4

Close up of the sun this summer, while trying to image venus during inferior conjunction with the sun:

sunspot 8/13/2023 20:05 UTC

I failed to image venus during inferior conjunction with the sun.  The conditions were frustrating: very bright, hot, poor seeing, and windy.  I was able to see it visually, but had difficulty focusing the camera, so slewed to the sun with a solar filter to focus on an obvious target.  while focusing, i noted a bright spot on the ground...the lens cap had blown off the finder scope objective leading to this unplanned modification of the eyepiece lens cap.  At that point I abandoned the attempt.  

Finder scope:

hole burned in finder scope lens cap

boring test stuff:

i cannot focus manually :(

best manual:

typical auto:

autofocus with light clouds
1/1000s

IR/UV block filter off center 4x exposure:

1/250 sec

125x exposure:

1/8 sec

125x exposure no IR/UV block filter:

1/8 sec

1000x exposure no filter, f/4:

1 sec

1000x exposure no filter f/5.6

1 sec

imaging details:

full disk testing 9/30/23

nikon D850

AF-S NIKKOR 300mm f/4E PF ED VR

Baader solar film, Fotga IR/UV cut filter

iso 100

sunspot

camera ZWO ASI 290MM with 850 nm IR pass filter, baader solar film

celestron 11" Edge HD

mediocre seeing

8/13/23

East Bluff, CA

Lunar Rays

Lunar rays, streaks of debris radiating out from craters, are among the few structures better seen during a full moon than a partial phase

Technically, there are 2 other types of lunar rays:

1. rays of light shining through a break in a lunar mountain range/crater during lunar sunrise.  these esoteric phenomena are challenges for advanced lunar observers and difficult to catch. 

2. a bunch of dudes named Ray something...(sorry)

The massive ray structure around tycho (lower right below) is easily seen though binoculars:

massive lunar rays surrounding tycho (right below center)
copernicus and kepler (middle, below center) 
full moon 11/27/12

The butterfly pattern around crater proclus suggests a low angle impact:

lunar rays around crater proclus
8/29/2023 06:42 UTC
(click for full size)
top full moon picture above

Menelaus and rays
8/29/23 06:59 UTC
(click for full size)
upper mid left full moon image

craters messier a and b are thought to have formed by a single  impacting body coming in at a very low angle:

Messier A and B
8/29/23 06:48 UTC
upper right full moon image

Here's a mosaic of craters copernicus and kepler and surrounding rays.  (left the rough edges for the mosaic feel).  click for a moon walk:  

Copernicus and Kepler
9 panel mosaic
8/29/23 07:05-07:17 UTC
(click for massive size)

Imaging details:

the full moon is usually the bane of astrophotographers

in accordance with murphy's law

it took me months to capture images during a full moon when i actually wanted to due to cloud cover.  

camera ZWO ASI 290MM with 850 nm IR pass filter
celestron 11" Edge HD
mediocre seeing
8/29/23 06:41-07:17 UTC

lunar waxing gibbous 12.5 days old

East Bluff, CA
captured in fire capture
stacked in autostakkert

light wavelets in registax
mosaic in maxim (tried and true worked amazingly well)

photoshop
topaz denoise worked wonders for slight noise reduction and dramatic detail recovery
(first sharpening has ever worked well for me in topaz)
low light
remove noise 1
enhance sharpness 63

full disk

11/27/12

FS 102, SX H9 (probably)

saturn opposition 2023

managed to have clear skies, decent seeing and the next morning off enabling me to catch saturn at the exact time of opposition and within minutes of local transit:

Saturn 8/27/23 08:16 UTC
Eastbluff, CA

here's a wider view with the moons.  

Saturn and Moons
8/27/23 07:54 UTC
composite image

none of the bright moons were blocked by saturn's glare, though several were out of the field.  had i known i would have captured a wider mosaic to catch them all.  

Dew soaked imaging rig:

Imaging details:

camera ZWO ASI 290MC with IR block

ZWO ADC

celestron 11" Edge HD, no barlow

East Bluff, CA

close up:

16 x 90 second captures, 1 x 422 sec

gain 351, exposure 1.988- 8.904ms, 77%-29% histogram, 100-200 fps

wide view:

composite

60 sec gain 351, exposure 100ms, 100% histogram, 10fps

60 sec gain 351, exposure 9.497ms, 89% histogram, 24 fps

captured with firecapture

stacked in autostakkert (upsampled 1.5x)

combined in winjupos 

processed in registax and photoshop

notes:

image snapped to focus on titan

meridian flip in past created tube currents in perfectly calm scope

cooled down aiming at planned imaging location in sky

fire capture ADC adjustment worked really well (custom button assigned for easy access)

blow drier much better than dew heater

dramatic increase in histogram after use mid capture

best images initial or after blow drier

shorter exposure better for 30% histogram 

(80% histogram exposure limits capture rate)

longer imaging time better

7 minute capture slightly worse after winjupos derotation

(required debayering of long AVI in PIPP)

but still better than 90 second.  

should increase to 120 for saturn

needed to set LD to .5 in winjupos

 

appendix:

3x no fan

0757

FPS (avg.)=39

Shutter=8.904ms

Gain=351 (58%)

Histogramm=77%

0758 

FPS (avg.)=112

Shutter=8.904ms

Gain=351 (58%)

Histogramm=74%

0800

FPS (avg.)=106

Shutter=8.904ms

Gain=351 (58%)

Histogramm=71%

3x fan on (no clear difference)

0802

FPS (avg.)=109

Shutter=8.904ms

Gain=351 (58%)

Histogramm=69%

0804 

FPS (avg.)=106

Shutter=8.904ms

Gain=351 (58%)

Histogramm=72%

0806

FPS (avg.)=108

Shutter=8.904ms

Gain=351 (58%)

Histogramm=72%

3x short exposure/low histo (no clear difference)

0808 

FPS (avg.)=199

Shutter=4.754ms

Gain=351 (58%)

Histogramm=42%

0810

FPS (avg.)=194

Shutter=4.754ms

Gain=351 (58%)

Histogramm=38%

0812

FPS (avg.)=194

Shutter=4.754ms

Gain=351 (58%)

Histogramm=36%

3x saa after blow drier (clearly better)

0821

FPS (avg.)=192

Shutter=4.754ms

Gain=351 (58%)

Histogramm=72%

0824

FPS (avg.)=192

Shutter=4.754ms

Gain=351 (58%)

Histogramm=71%

0826

FPS (avg.)=171

Shutter=4.754ms

Gain=351 (58%)

Histogramm=70%

3x shorter exposure.low histo

0828

FPS (avg.)=207

Shutter=1.988ms

Gain=351 (58%)

Histogramm=31%

0829

FPS (avg.)=217

Shutter=1.988ms

Gain=351 (58%)

Histogramm=32%

0831

FPS (avg.)=218

Shutter=1.988ms

Gain=351 (58%)

Histogramm=33%

0833 

FPS (avg.)=215

Shutter=1.988ms

Gain=351 (58%)

Histogramm=30%

0843 long run

FPS (avg.)=209

Shutter=1.988ms

Gain=351 (58%)

Histogramm=29%

not perseids

while there were many satellites, here's and egregious "satellite storm" (thanks elon)

satellite storm
and one airplane
8/13/23 04:33-04:35

There were also a number of these flashes resembling bright meteors at first glance:

bright flash
8/12/23 20:21 PDT
Anza, CA

However there were invariably trails across several consecutive 20 second captures establishing them as slow movers compared to meteors:

I'm guessing this is a starlink panel reflecting sunlight right at my location, but it does not show up in the heaven's above site.  

Lastly, this frame caught my eye due to the similarity between the "star clouds" in the milky way (star field so dense that stars can't be distinguished as points) and the more mundane water-droplet-in-the-sky type:

Clouds in Space and Sky

Here's a cleaner version of the milky way, my best close up to date:

Milky Way Crop
8/12-13/23
Anza, CA

imaging details:
5/12-13/23 10 PM to 5 AM
Anza, CA
passing clouds
nikon D850
Sigma 15mm F/2.8 EX DG fisheye
20 sec, iso 1600

milky way second image stacked 144x20 sec raw .NEF files in Registar which did an amazing job correcting field curvature, processed in Maxim and Photoshop.  The posted image is 25% of full size

perseid close up highlights

 a few highlights at a uniformly larger scale:

longest
warped by fisheye lens field curvature
and surrounded by green air glow
as it skimmed by low on the horizon
8/12/23 21:43 PDT

shortest
bright, but very foreshortened
coming almost straight in
8/13/23 03:02 PDT

The reason for the color is complex.  I thought it was simple black body radiation, but these are really only red and green.  ionization of the atmosphere occurs as the meteor burns up: the heated air glows red or green due to oxygen and nitrogen.  a similar phenomenon is involved in auroras and sky glow.  this can be be influenced by the speed and altitude of the meteor.  the composition of the meteor can also play a role as different metals can glow at different colors.  

cloud cutter
8/13/23 02:54 PDT

passing andromeda (upper right)
8/13/23 02:02 PDT

Double?
not sure on the left one
8/13/23 01:58 PDT

slide show of the bright ones:

residual ionized glow after anza house skimmer:

close inspection shows a faint trail left in the frame after the meteor appears
which gradually rises up in subsequent frames
would that the lights had been out :(
8/12/23 23:06

another:

faint trail left in the frame after the meteor appears
which gradually rises up in subsequent frames
8/13/23 00:12

the next night, dave kodama caught a really bright one here

imaging details:
5/12-13/23 10 PM to 5 AM
Anza, CA
passing clouds
nikon D850
Sigma 15mm F/2.8 EX DG fisheye
20 sec, iso 1600

Perseids 2023

perseids wide field 8/12-13/23
north lower right
radiant at perseus right side

having repeatedly tried and failed to catch any meteor images in my back yard over the past few years, i elected to go out to the Orange County Astronomers dark sky site in anza to image this year's perseids with near new moon conditions.  

Burn line from recent fires near OCA site
Dave Kodama's cameras ready to go

OCA regular heungsoo choi in action

perseid buzzing OCA's anza house 8/12/23 23:06

while i've seen meteor showers from dark skies, including Yosemite and Yellowstone parks, this was in many ways the best.  others have had more frequent bursts, but these were typically faint white lines.  this night's show was filled with bright orange streaks.  by no means a meteor storm--the bright one's trickled in, but there were more than i've ever seen.  over the course of 7 hours, even with passing clouds, my camera captured 21 bright meteors.  they were rainbow colored in the camera, changing from red to green as they heated in the atmosphere, despite an orange visual appearance.  

perseid 8/13/23 00:50 local time

there were many faint meteor candidates, but  they were difficult to confirm due to abundant satellite traffic.  i only included bright streaks that were colored and directed towards the radiant in perseus. 

I used a fisheye lens to capture a wide swathe of sky, nearly horizon to horizon:

milky way center, perseid top left
N-north star, A-andromeda galaxy, P-constellation perseus
northern horizon bottom left
southern horizon top right
SUV bottom right :(
8/13/23 00:50 local time 

sadly, there were clouds passing through many of the images, making a composite difficult.

Star trails 8/12-13/23
polaris, north star lower left
anza house bottom left corner
my annoying SUV side light bottom right corner
southern horizon top right corner
(click for larger size)

typical recommendations are to just sit back and look up to view meteors. 

meteor shower observing accessory

the distribution in this capture was skewed towards the radiant in perseus on the horizon.  however, many of those were foreshortened with longer streaks on the opposite horizon.  

perseid distribution map 8/12-13/23
(click for larger size)

the best time to view meteors is between midnight and dawn.  i've also read 4 AM.  

a steady stream with clusters at 2AM and 3AM

imaging details:
5/12-13/23 10 PM to 5 AM
Anza, CA
passing clouds
nikon D850
Sigma 15mm F/2.8 EX DG fisheye
20 sec, iso 1600

missed the first hour as i set the camera delay to 20 minutes instead of 20 seconds between shots :(

the last meteor was caught at 5 AM, after astronomical dawn.  i saw several bright meteors as i was setting up, so i should have started imaging much sooner despite the "after midnight" recommendations.  

Venus and Mercury

took another crack and venus and mercury.  unfortunately seeing was not great...

Venus 4/16/23 02:43 UTC
IR pass 850nm

Mercury 4/16/23 02:33 UTC
IR pass 850nm

i decided image venus during the day (venus is bright enough to see in broad daylight, it's just really hard to find) for 2 reasons: 

-all other things being equal, the seeing should be better with the planet at higher altitude 

-i was hoping to capture motion of venusian clouds by imaging over a long period of time.  

sadly it was a total bust. imaging runs over 20 minutes captured no cloud detail whatsoever (until earthly clouds obscured my view).  perhaps a hint of something towards the upper half as venus got lower in the sky:

Venus 4/17/23 00:36 UTC
UV

Venus 4/17/23 00:05 UTC
IR pass 850 nm

at a recent meeting of the OC astronomers, Chris Go (who admittedly doesn't image venus) suggested that sunlight saturates the daylight sky with UV ruining the detection of clouds.  or perhaps it was just a clear day on venus ;)

I have captured cloud detail in the past with this set up at twilight:

venus UV clouds

Image details:
camera ZWO ASI 290MM 
filters: ZWO IR pass 850, Baader U-filter bw 320-380nm
celestron 11" Edge HD
East Bluff, CA

4/16/23
mediocre seeing
02:43 UTC
2x barlow
IR pass 850 filter:

venus
FPS (avg.)=215
Shutter=0.746ms
Gain=351 (58%)
Frames captured=69635

mercury
02:33 UTC
2x barlow
FPS (avg.)=116
Shutter=3.281ms
Gain=436 (72%)
Frames captured=12765

4/17/23
Venus 
no barlow as UV is faint
mediocre seeing

UV filter:
00:36 UTC
FPS (avg.)=217
Shutter=2.055ms
Gain=351 (58%)
Frames captured=39233 

IR filter:
00:05 UTC
FPS (avg.)=42 ?!
Shutter=0.191ms
Gain=351 (58%)
Frames captured=12865