Try increasing gamma if dark sections aren't distinguished

Try increasing gamma if dark sections aren't distinguished

Thursday, October 31, 2019

witch's broom and the veil

  here's the witch's broom nebula:



and the ghoul:

both are part of the veil supernova complex

haunting tale:
7,000 years ago, a massive star burned out, collapsed, and then exploded, creating a supernova.
several thousand years later, prehistoric man looked up in the sky and saw a bright light visible during the day
that lasted for weeks. 
(this was about the time the monolith arrived)

200 years ago, with the aid of the telescope, man discovered
the expanding cloud of gas created by the supernova.
it is very large (3 degrees, or 36x bigger than the full moon) and very faint.
the witch's broom (above) is one edge of the expanding cloud
the other side is shown below at a smaller scale
you can almost see a bow wave ahead of it:


here's the whole thing (click for full size):

Veil nebula
this is a 4 panel mosaic with a total of 32 hours of exposure time
taken over the course of 2 months

~700,000 years from now the expanding shock wave will hit our planet
what will happen to life was we know it?

the bright side (from NASA):
"Although only about one star per century in our Galaxy will end its life in this spectacular way, these explosions are responsible for making all chemical elements heavier than iron, as well as being the main producers of oxygen in the universe. Elements such as copper, mercury, gold, and lead are forged in these violent events. The expanding shells of supernova remnants mix with other clouds in the Milky Way and become the raw material for new generations of stars and planets. The chemical elements that constitute Earth, and indeed those of which we ourselves are made, were formed deep inside ancient stars and distributed by supernova explosions in nebulae like the one we see here".

P.S. recent data indicates heavy elements being formed by neutron star mergers in addition to super novae (confirmed spectroscopically) , something new under the sun. 

On that note:
happy halloween

Sunday, October 13, 2019

Jupiter Methane filter

after catching a glimpse of jupiter's great red spot starting to unfurl, i picked up a methane filter (which enhances the great red spot...and looks cool ) to see if i could better detect the activity.  it's a bit hard to wrap your head around what a methane filter does.  the short version is that high altitude clouds on jupiter (including the great red spot) appear very bright with a methane filter (detailed discussion below).

in the methane filter image below, there is high signal at the great red spot (a giant storm high up in the atmosphere), at a high altitude equatorial belt, and at polar clouds.  in contrast the signal is extremely low on the east and west sides where the light passes tangentially through extremely thick layers of methane: 
Jupiter 7/21/2019 05:54 UTC RGB left, Methane center, Methane(as red)-GB right


The swirls around the GRS (center) and red trail (right) might be related to the GRS unfurling: 
Jupiter 6/29/19 06:17 UTC, Europa upper left




Jupiter 6/27/19 05:23 UTC 

here's my take on methane filters.  methane (CH4 for you organic chemistry fans) is present throughout the atmosphere of the gas giants in our solar system.  it generally absorbs light in the red end of the spectrum.  the methane filter only passess light in a very narrow range around a specific *absorption* band of methane in the infrared (no green house gas comments please).  since the gas giants are full of methane, they actually appear very dark with a methane filter (in contrast, the jovian moons are extremely bright relative to jupiter with this filter as they have no methane).  so when sunlight hits jupiter and reflects back to us, the light travels through less methane where high altitude clouds reflect the light back (so less light is absorbed).  the higher the clouds, the brighter the signal (factor of 2 here since the signal is absorbed on the way in and out). 

here's a sequence of jovian moon europa (which has no methane atmosphere) passing across the surface of jupiter.  reflecting all the methane signal, europa is extremely bright in the methane images, in contrast to the dark disk where methane absorbs the light: 


conversely, europa is barely detectable in the visible light images as jupiter's surface shines so brightly: 


Imaging details:
camera ZWO ASI 290MM with ZWO RGB filters
Baader methane 889 nm 8 nm bandwidth
celestron 11" Edge HD
East Bluff, CA
90 second captures, 2x binning for methane
no barlow

7/21/19
2 captures each filter
upsampled 2x for processing, then reduced to 60%
6/29/19
4 captures each filter, except 12 for methane
6/27/19
2 captures each filter

gain 351, exposure ~0.6-1.0 ms, 30% histogram, ~280 fps
methane exposure 111-240 ms, 3-8 fps