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)
captures with firecapture @ ~58 fps
stacked in autostakkert, Drizzle 3x, then reduced to 1.5x, sharpened in registax 6
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.
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:
cellphone Droid turbo
Eastbluff, CA 1/14/18
Lunt 60 PT 
ASI 290 MM camera
20 second video 183 fps
Shutter=5.0 ms
Eastbluff, CA 1/4/18