Try increasing gamma if dark sections aren't distinguished

Try increasing gamma if dark sections aren't distinguished

Sunday, January 28, 2018

Copernicus infra red

Here's a close up shot of copernicus, one of the most photogenic craters on the moon with its terraced walls and central peaks: 
Copernicus 9/10/16 infra red filter
click for moon-walk size


it's easily visible to the naked eye here:
7/8/17 IR/UV block filter


Interestingly, the crater was named by a jesuit at a time when church doctrine opposed the heliocentric model.  The crafty jesuit justified naming such a prominent crater after the father of the heliocentric model by noting that the astronomer was placed in oceanus procellarum, the "ocean of storms". wikipedia link with more information about the crater

The image of the crater was taken with an infra red filter and a telescope that is "mostly" a reflector (mirrors).  it was a test shot which proved that the IR filter was sharper than standard visible filters.  more on that in this post on jupiter.  
Interestingly, the full disk image was taken with a filter that blocks infra red.  why? it was taken with a refractor.  refractors use lenses to bend light.  since infrared light bends less than visible light (the same phenomenon that made it desirable in the previous image), it doesn't focus well in refractors, creating a blurry image.  


Technical notes:
Copernicus: celestron nexstar 8 GPS (8" SCT on a wedge)
ZWO ASI120MM-S
captures with firecapture @ ~58 fps
stacked in autostakkert, Drizzle 3x, then reduced to 1.5x, sharpened in registax 6
9/10/2016
Full disk: DMK 51 and the tiny tak, Takahashi FS-60C, 60 mm aperture at f/4.2 with a reducer.  The field of view is approximately 96x72 arc minutes.  1 minute video capture at approximately 12 fps, aligned in autostakkert, wavelets in registax.
7/8/2017
Eastbluff, CA

Sunday, January 14, 2018

Sunday Sundogs and a pillar

saw a pair of Sundogs while running in the back bay today.  pointed them out to everyone i passed.  most thought i was crazy, but one couple shouted a "thank you" after they found it.



Sundogs 1/14/18



Sundogs are caused by light refracting off hexagonal ice crystals.  if they are random a halo is formed, if they are horizontal, two spots are seen on either side.  Here's a nice explanation.  

Here's a phenomenal example of a double solar halo with sunddogs taken from a ski slope in sweden:

speaking of solar images, here's an Ha image of a "straight pillar"--a form of solar prominence:


Image details:
sundogs:
cellphone Droid turbo
Eastbluff, CA 1/14/18
Ha:
Lunt 60 PT 
ASI 290 MM camera
20 second video 183 fps
Shutter=5.0 ms
Eastbluff, CA 1/4/18

Sunday, December 31, 2017

2017 eclipse experiance

Then totality.
the sky darkened, but was still visibly blue
i viewed the eclipse through light cloud cover
perhaps making this experience a bit different, with less darkening of the sky.

i elected to watch the first diamond ring looking down at my laptop to protect dark adaptation.  while looking down i noticed shadowbands sweeping along the sidewalk then,

OH MY GOD, THERE IS A HUGE BLACK HOLE IN THE SKY WITH A HALO OF LIGHT AROUND IT


i picked up my canon 15x50 image stabilized binoculars to get a closer look at the corona.  after a second of viewing i thought something like "why do i have a piece of glass between me and a direct view of god?" and put the binoculars down...an alarm reminded me when it was time to get back to imaging

it wasn't the darkness of the sky that overwhelmed, but rather the black hole in the twilight sky which seems to lead to another universe/reality... 
click on image for full size


another alarm goes off and i look up to catch the final diamond ring.  a pinpoint of light appears at the right edge of the black hole in the sky, brightening steadily until it is too brilliant to look at. 

last alarm, filters back on.





The image above is a remarkably accurate portrayal of the visual experience (to my eye).  the main shortcoming is that it's difficult to portray the scale of the event.  try to envision the black circle in the image at the size of a full moon rising, dominating the horizon.  interestingly, it was the combination of two mediocre images (both shown in previous posts): an over exposed cell phone shot and an out of focus telephoto image with my DSLR.  having succeeded in combining a color image with my telescopic view, i tried combining these two on a lark.  after two minutes of aligning the spikes of the corona in the two images, i adjusted the opacity and my jaw dropped, bingo.  

while in casper for the eclipse, i attended a talk by archeoastronomer J. McKim Malville at the astronomical league conference.  He has studied a number of stonehenge-like sites, one of which featured a petroglyph (stone carving) of what appeared to be a total solar eclipse with a coronal ejection mass.  After seeing an eclipse, i can see what motivated these strucutres.  

Lastly, thanks to Ellen Pothier for having the foresight to bring corona:

Otherwise,  there'd be a bud light joke here



Image details:
-sun and corona:
Nikon D-60, AF-S DX NIKKOR 55-300mm f/4.5-5.6G ED VR, f/5.6 300 mm 1/20" iso 400
Landscape:
-cell phone, Droid Turbo ;)
Casper Wyoming
42,50.9694N 106,15.5688W
8/21/2017