Thursday, September 21, 2017

great american eclipse shot: casper wyoming travelogue

I chose Casper Wyoming for the eclipse for several reasons:

1 historically it had the greatest chance of clear skies at that time and date of any region on the eclipse track

2 it has a local airport making it easy to get in and out, important given dire predictions of crowds traffic jams and gas shortages

After a smooth flight to the airport, i found the google satellite image of my hotel somewhat disconcerting:
Hotel not yet built in google maps images

needless to say i paid triple that rate at eclipse time.

so what gives?

north view from hotel:
Casper's Eternal Flame and cloud cover...

locals informed me, Casper is a boom or bust town, currently driven by natural gas,  not booming at present.

so i had a brand new hotel with brand new shopping malls at the edge of town designed for expansion that wasn't happening.  so much for the crowds. 

i had allowed 3 hours for the 20 minute ride to the airport after the eclipse...

and made it in 15 minutes.  all the traffic was north south after the eclipse, not east west to the airport.

that being said, folks that attempted to drive north to the eclipse track on the morning of the event were basically stuck on the freeway, unable to make it. 

spent one late night stargazing up in casper mountain.  the views were stunning, but no pics (another story):
Sunset, Casper Mountain Wyoming
Casper Mountain Panorama
click for full size


despite long term predictions, and near term forecasts for clear skies, i came very close to being clouded out. 

after a beautifully clear morning, here's the sky to the northeast 15 minutes before totality:


weather radar from eclipse day:
note thin line of clouds moving right over Casper
Thanks to Dave Kodama for the image


I actually viewed and imaged the eclipse through clouds:
Great American Eclipse
8/21/17

overexposed, but you can see a hint of the corona's triangular spikes, and of course the thin clouds.
i think scattered light from the clouds kept the sky lighter than most eclipse accounts. 

by 4th contact (end of partial eclipse)
the sun was completely obscured by clouds:
4th Contact
More to follow...

Image details:
cell phone Droid Turbo ;)
Casper Wyoming
42,50.9694N 106,15.5688W
8/21/2017
Casper Mountain
8/18/2017

Tuesday, September 5, 2017

2017 total solar eclipse composite images

First here's a different version of an image of the faint outer detail of the corona (be sure to click on images for full size): 
8/21/17 solar eclipse

Used a radial blur subtraction technique to enhance the contrast of the corona, compensating for some of the bright light from the inner corona scattered by clouds by bringing out more detail, especially the subtle loops lower left.    

An issue with images of the eclipse is that there is an extremely large range in brightness, more than can be encompassed by a picture on a video monitor or print out.  A "composite" image combines the faint detail from an image that over exposes the bright inner sections (see above) and the bright detail from an image that misses the faint detail.  

Here's my attempt at a composite:
8/21/17 solar eclipse composite


Unfortunately, all my attempts at compositing seemed to yield a mediocre version both the bright and the faint detail.  

Here are a few alternative versions, using tricks to provide maximum detail in both versions by inverting the color of one:
8/21/17 solar eclipse exclusion composite
8/21/17 solar eclipse inverted exclusion composite



Just for fun in the last set, I colored the bright detail red, which is appropriate as the chromosphere is actually red:


Image details:
DMK 51 web cam, Takahashi FS-60C, 60 mm aperture at f/4.2 with a reducer.  Baader solar film, Fotga IR/UV cut filter.  The full field of view is approximately 96x72 arc minutes with a resolution of 3.6"/px.  video capture at 12 fps, aligned in autostakkert, wavelets in registax.
Casper Wyoming
42,50.9694N 106,15.5688W
8/21/2017

Sunday, August 27, 2017

2017 total solar eclipse images

partial phase, moon about to gobble up spots:
a few sunspots are noted in the photosphere, the bright visible surface of the sun.  

almost there...


"diamond ring"--final flash of direct sunlight at the start of totality (click for full size):


TOTALITY 
bright prominences in the chromosphere are visible with direct sunlight blocked:
8/21/2017 Total Solar Eclipse
with the bright photosphere hidden, prominences in the chromosphere can be seen.  the temperature increases from 6,000K F in the photosphere to up to 20,000K in the chromosphere.  

longer exposure brings out the outer corona, easily visible to the naked eye, note the magnetic field lines arcing out of the poles, and the subtle arcs lower left (click for full size):
8/21/2017 Total Solar Eclipse
click for full size
The temperature in the corona reaches 1,000,000 K, the reason for this remains unclear.  

Image details:
DMK 51 web cam, Takahashi FS-60C, 60 mm aperture at f/4.2 with a reducer.  Baader solar film, Fotga IR/UV cut filter.  The full field of view is approximately 96x72 arc minutes with a resolution of 3.6"/px.  20 second video capture at 12 fps, aligned in autostakkert, wavelets in registax.
Casper Wyoming
42,50.9694N 106,15.5688W
8/21/2017