Try increasing gamma if dark sections aren't distinguished

Try increasing gamma if dark sections aren't distinguished

Monday, May 20, 2024

4/8/24 solar eclipse travelogue, Russellville Arkansas

a thin cloud across the sun during totality didn't really interfere with the visual experience (photos another story).  i could easily see the black disk surrounded by a glowing ring of light, and colored prominences.  that being said, someone about 100 miles north along the track reported clear skies for totality :(

Thin cloud passing right in front of eclipsed sun. 
Russellville, Arkansas 4/8/2024
also note Venus (right) and Jupiter (left)

The first thing i did in planning for the 2024 eclipse was to find the location with the best chance of clear skies...
Bad news.  Based on historical data, the chance for clear skies was less than 50% across the entire US eclipse path, with the chance being best in the south and worse further north.  Furthermore, the weather patterns were such that large swathes of the path would be taken out all at once, so not easy to drive to clear skies.  

after hours combing through this website run by eclipsophile  meteorologist Jay Anderson, i came up with Kerrville Texas as the best location, with Russellville Arkansas as a back up, and Cleveland as a third (a friend from Cleveland talked me out of this one).  I booked refundable flights and rooms for both, making the final decision two days before the eclipse when weather models can be fairly accurate.  At that point the chance of heavy clouds was near 100% for southern texas and very low for arkansas. ironically maine, which a priori had the worst chance of clear skies wound up being the best:
weather satellite view of the eclipse shadow from 
pivotal weather.com




russellville seemed a pretty popular destination for the west coast



many people watched the eclipse from in front of the hotel where they were renting out parking spaces next to a lawn.  playing up to the event, the hotel gave out schwag bags including sun chips, capri sun, star burst, and eclipse gum...i had my own bud lite.  from there, they viewed the eclipse over the holiday inn--a great ad, but not the most scenic.  

after scouting a few locations in the area, i went back to my hotel and spotted a nice green pasture with a few cows right out back (seemed very Arkansas): 
eclipse scouting, holiday inn, Russellville AR

Will the cows moo at the moon covered sun?


more details:
samsung galaxy S22 ultra

detailed interactive eclipse path:
http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_2024_GoogleMapFull.html
also links to optimal exposure times

eclipse weather:
https://eclipsophile.com/2024tse/
weather in arkansas typically better slightly north of center line, hence russellville

last minute weather:




Thursday, May 16, 2024

5/15/24 surreal sunset in front of clouds?!

Driving home the other night i caught something odd out of the corner of my eye at sunset:  the horizon was bright orange with the setting sun lighting up a thin cloud.  below that a thick bank of dark clouds went down to the horizon.  in front of that was the grapefruit pink disk of the setting sun.  

WAIT, IN FRONT OF THE CLOUDS?!

I pulled over and snapped these pics with my phone (click for larger size):






captured these images at back bay park overlook, as amazed by the sight as by the fact that joggers and cyclists passed by paying no attention. 

a woman wearing a white baseball cap power-walked by with her eyes down at her phone. i gestured to the horizon and said "have you seen it?"

she looked up at me like i was a lunatic (guilty), looked back down at her phone, and kept walking :(





simple explanation is that the sun is shining through the clouds. 
i have a feeling there's a bit more going on: the top of the grey cloud bank looks just too dark and thick to let the sun through, but lower down, at the level of the sun it seems to lighten a bit. 
i'm thinking the refracted sun is passing through a lighter layer of clouds/fog lower down.

image details:
5/15/24 7:42 pm local
backbay park overlook (easbluff and jamboree), newport beach, ca
samsung galaxy S22 ultra



Tuesday, May 14, 2024

4/8/24 solar eclipse chromosphere animation (pretty red stuff)

Chromosphere
total solar eclipse (late totality)
4/8/2024 1:53:58 pm local
eastern limb up

The chromosphere is the layer of red hydrogen plasma that sits above the photosphere--the bright surface of the sun that emits the full spectrum.  during a total solar eclipse the photosphere is completely blocked, allowing one to see red arcs of hydrogen plasma jutting off the side of the sun with the naked eye.  Here are a series of images at short exposure, showing the chromosphere, without the extended outer corona of the sun or the brilliant photosphere.  

Fortunately, I previewed Ha images of the sun shortly before the eclipse, so knew to look for the red arc on the lower right (see video) towards the end of totality.  It was spectacular visually, even through light clouds.  

Be sure to click on full size.




Imaging details:
4/8/24 
Russellville, AR
35 deg 18.366 min N
93 deg 7.962  min W
~1:50-1:54 PM local
nikon D850
AF-S NIKKOR 300mm f/4E PF ED VR
f/5.6, iso 100, 1/6400-1/800 sec exposure
skywatcher star adventurer tracking mount
eclipse orchestrator for automated image capture
oriented solar north up now.  

processing notes:
matched the exposures in photoshop camera raw to 1/3200 sec
aligned the frames on the corona manually so the moon is moving across the stationary sun
because it was much harder to do than auto align on the moon, so why not?
shot continuously at 2 second intervals in the beginning and end.  mid eclipse images were spaced further out due to longer exposures, so i used the "tween" function in photoshop to give a smoother transition between frames (adjusting the number of interpolated frames to the elapsed time).  

Saturday, May 11, 2024

active region 3664 and the great magnetic storm of '24

Here's a relatively large group of sunspots known as AR 3664:

active region 3664 5/11/24 21:36.9 UTC
red filter (Ha off band)

Earlier this week the magnetic field associated with this sunspot grouping blasted high energy plasma directly at our planet.  As a result, we experienced the biggest geomagnetic storm in more than 20 years last night, leading to auroras being seen as far south as the Florida keys.  members of my astronomy club were able to capture a red glow in the sky with cameras.  It was reportedly quite impressive around midnight from anza borrego.  sadly it was cloudy at home.  

Spaceweather.com writes:

"The low latitude of these sightings would seem to place this storm among the greatest aurora displays of the past 500 years"

The sunspot grouping is quite similar to the one that caused the carrington event (largest geomagnetic storm in history).  here it is earlier this week with the sunspot grouping of the carrington event superimposed (spaceweather.com).  

A stronger flare occurred today with a significant component directed at the earth so there may be more storms coming...


Here's an animation showing the sunspots in hydrogen alpha and red light:

AR 3664 5/11/24 Ha and red light


Current aurora forecast:

Last night's:

from spaceweather.com:

"ANOTHER SIGNIFICANT CME IS COMING: Giant sunspot AR3664 unleashed another X-flare today (May 11th @ 0139 UT)--its strongest yet. The X5.8-class explosion produced a significant CME with an Earth-directed component...

This CME could reach Earth on May 13th, adding new power to the ongoing geomagnetic storm. CME impact alerts: SMS Text"


Follow up: 
the second CME did not cause a significant geomagnetic storm.  However on 5/14/24 as AR 3664 was rotating off the visible disc (not pointing at us) it gave off the biggest solar flare of this cycle which peaked at X8.7
according to spaceweatherlive.com
it was a β-γ-δ – Beta-Gamma-Delta magnetic class sunspot,
so basically a mishmash
the delta being sunspots containing opposite polarity in the same umbra which typically give the highest energy eruptions.


Image details:
East Bluff, CA
5/11/24 
21:34.2-21:36.9 UTC (2:30 PM local)
light clouds, mediocre seeing

Lunt 60/50 double stacked B1200 for Ha, single stack for off band
manual guiding with alt-azm mount
zwo ASI 290MM
20 second captures
best 50%

Ha
Frames captured=2236
FPS (avg.)=111
ROI=800x800
Shutter=0.174ms
Gain=351 (58%)

off band single stack
Frames captured=2237
FPS (avg.)=111
ROI=800x800
ROI(Offset)=0x0
Shutter=0.032ms
Gain=345 (57%)

AR 3664 Ha 
2024-05-11-2134.2 UTC