Sunday, February 26, 2017

crescent moon, hollywood style

What's wrong with this picture (click for full size)?

nothing really, except that the crescent is facing the wrong way. 

though few people can say which way the crescent moon should be facing

they have a visceral feeling that this isn't right.

when the moon is a thin crescent, it means that the sun is illuminating the side which is not facing us, so the moon has to appear very close to the sun in the sky: the crescent moon is seen just after sunset or just before sunrise, with the crescent facing down at the sun below the horizon (tips pointing up).  in the northern hemisphere it points down and to the right at sunset (looking west with sun setting in the southwest).  
you morning people may know that the crescent lies down and to the left in the east.  
it's the opposite in the southern hemisphere.
OK that was really confusing
here's a better description.  

for bad astronomy blogger Phil Plait, this knowledge turned his world upside down

DOH!
he concluded that springfield must actually be in the southern hemisphere based on this scene from the elon musk episode of the simpsons.


the only way the crescent can be on the top of the moon is if you're standing on your head, or in outer space where up and down doesn't matter.  or perhaps some strange partial lunar eclipse.


i chose this orientation as the unnatural rotation gives it a spacey feel

kubrick was well aware of this:

by the way, here's one of the most over-the-top analyses of a movie i've ever seen
tons of fun


but for the clouds you may see the crescent moon in the next few nights
take a look and see what's missing from my image
to be continued...




-bill w

Technical notes:
web cam, 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.  Each image is a one minute video capture at approximately 12 fps, aligned in autostakkert, wavelets in registax.

Sunday, February 19, 2017

testing 1-2-3, preparing for the eclipse

testing out my imaging rig for the 8/21/17 total solar eclipse.  there will be a range of exposures so decided to shoot filtered midday sun, twilight moon, full moon.  Here are a few images (click on image for full size):
Sun white light filter 2-4-2017

Moon 2-4-2017
Moon 2-12-2017

Moon at twilight 1-30-2017 grey scale

Just for fun, i decided to simulate an eclipse with the images.
I selected the image closest to full and superimposed it on the solar image.
To my chagrin, the moon did not totally cover the sun--that whole perigee apogee thing--I'd created an annular eclipse.
so i had to use an image from another day when the moon was closer to the earth and large enough to completely cover the sun.
Here's the comparison illustrating variation in the apparent size of the moon during its orbit around the earth:
Lunar images superimposed on solar

Technical notes:
decided to go with my widest field webcam and shortest focal length scope with a web cam, 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.  Each image is a one minute video capture at approximately 12 fps, aligned in autostakkert, wavelets in registax.

Tuesday, February 14, 2017

heart of the heart

here's a close up of "the heart of the heart", 
dust and gas near open cluster Melotte 15,
in the center of IC 1805, the heart nebula (click for full size):



in a massive cloud of dust and hydrogen in the constellation Cassiopeia,  the dust began to clump. 
what caused the clumping? 
a supernova, gravitational interaction with a nearby galaxy, or maybe a cosmic butterfly.  
gravitational attraction caused the clumps to get more and more massive, generating so much pressure that the clumps burst into flames as nuclear fusion commenced.  stellar wind from the new star cluster caused the dust to move away with hydrogen glowing red at the heart-shaped edges. 
in the center of the heart nebula lies a psychedelic collection of dust pillars.  the tips of the pillars are anchored by dense collections of dust--stars to be, or perhaps that will never be, as the surrounding dust is blown away.

For obvious reasons, i prefer this one in a more natural color palette (above), but here's a version in the Hubble palette with hydrogen as green, sulfur as red and oxygen as blue:



lastly, here's an older wide field view of the heart nebula at low power as it's quite large, 5 times the apparent size of the full moon: 

heart nebula aka IC1805

click for full size, note the central star cluster and dust pillars.  

image details:
8" LX200R, SX Trius 694 binned x 2 to 0.8"/px
astrodon 3nm OIII, 3 nm SII, 5nm Ha filters
ASA DDM60
OIII 6x20 min bx2, 13x20 min bx4, SII 3 x 20 min bx2, 39x20 min bx4, Ha 12x 20 minutes bx2
11/12/15-12/29/15
Eastbluff, CA
in processing, i accidentally overlaid the hubble palette version on the conventional giving a hint of color to the highlights, seemed to work, so i left it.  the silky smooth background is not due to the massive exposure time, but rather aggressive use of topaz denoise.
heart nebula:
FS60C f/4.2 FR CS 10 nm Ha/Baader 8.5 nm Oiii filters, H9
Ha 12/19/08
Oiii 12/22/08-ruined by gradients re-shot 1/17/09
2 panel mosaic 12x5 min each panel
los alamitos, CA
bortle white skies, poor to fair seeing, good transparency for area