Mars is here, 11/26/22. filter tricks--IR filter with RGB camera

 Mars is here.

The seeing wasn't great this session, so i imaged without a barlow.  I wanted to test out an infrared filter with a color camera which worked perfectly (see details below).

Mars 11/26/22 8:51 UTC
RGB left, IR 850 pass center, IR-RGB composite right

as i was breaking down the gear, i noticed that the stars were no longer twinkling ;) 
broke out the barlow and got less sleep than planned:

Mars 11/26/22 9:26 UTC
single 120 sec capture

Why an infrared (IR) filter works with a color camera:

the color filters in many color cameras pass infrared light.

(which is why you should use an IR blocking filter)

The ZWO 290 MC passes the IR from an 850 nm IR pass filter equally through all color filters.

as a result, you can get a uniform full resolution monochrome IR image when using an IR filter with a color camera.  

just be sure to set the color balance for all filters to neutral (see below).  

Image details:
11/26/22  08:34-09:26 UTC
celestron 11" Edge HD

first set
ZWO ASI 290MC (one shot color camera)
baader IR/UV block filter for RGB images
400 fps, .191 ms, 351 gain, 40% histogram, 120 sec x 4
ZWO IR pass 850 nm for IR images
set green and blue gain to .5 in fire capture for IR
400 fps, .855 ms, 351 gain, 35% histogram, 120 sec x 3

second image
ZWO ASI 290MC (one shot color camera)
baader IR/UV block filter
televue 2x barlow
152 fps, 2.132 ms, gain 291?, histogram 49%, 120 sec
single 120 sec capture

firecapture, autostakkert 5% stacked, winjupos, maxim, photoshop
elevation ~80 degrees
Eastbluff
Southern California

for IR-RGB blend IR was used as red channel and 30% luminance, color rebalanced on white pole structure.  

ref:

IR filter with ZWO camera

https://astronomy-imaging-camera.com/product/1-25-ir-850nm-pass-filter

"just don’t forget to keep the WB_R and WB_B to 50 (no White Balance applied)."

fire capture screen shots:

click for full size

click for full size

another try at mercury

detail on mercury is still on my wish list.  unfortunately, the goto on my failing mount is not up to mid day imaging.  so i gave it a shot as it set near the horizon.  seeing was pretty bad at low altitude.  a low pass IR filter pulled out the planet, but no evidence of detail. 

Mercury 5/4/22 02:56 UTC

processing notes:

for reasons which escape me, my stacking software (autostakkert) was completely unable to distinguish bright, but totally distorted frames (which were the majority) from a well defined crescent.  as i result i had to manually select approximately 200 frames out of 8,651.  a process made even more tedious by a windows update blowing all my work about half way done.  needless to say, this one sat on the hard drive for a while.  finally made it thru all the frames, but alas, didn't get anything more than a crescent, no detail.  to be expected i guess with such poor seeing.  

prior attempts

image details:

camera ZWO ASI 290mm IR pass filter 850
celestron 11" Edge HD, no barlow
8651 frames @75 fps 6.085 ms gain 351

upsampled ~2x
5/4/22 02:56 UTC (5/3/22 ~8 pm local)
East Bluff, CA
poor seeing, IR filter helped

more craters: petavius and langrenus

cruising along the 3 day old crescent moon from mare crisium leads to this pair of craters with prominent central peaks and terraced walls:

craters patavius and langrenus
3 day old moon 5/4/22 03:04 UTC

to the left is Patavius, notable for a 
-wide double rim
-complex central mountains 1.7 km from the floor and a 
-deep fracture from the peaks to the rim of the crater. 

Patavius

views of petavius are reportedly very sensitive to contrast:  

"The shadows retreat with surprising speed and for the rest of the lunation, until just after full Moon, Petavius is identifiable as a white oval. Its grandeur then reappears briefly before the whole region is engulfed by the lunar night."(Sir Patrick Moore)

to the right is Langrenus notable for a 

-20 km wide terraced rim 3 km high on the eastern side

-1 km central peak

Langrenus

there is a ray system on the crater floor which appears when the sun is directly overhead (not evident in this image).  

In 1645, Michel Florent van Langren was the first person to draw a lunar map while giving names to many of the features. This is the only one of his named features that has retained his original designation (wikipedia). 

Among his contributions were attempts to determine longitude...He believed he could improve the accuracy of longitude determination, particularly at sea, by observing peaks and craters of the Moon as they appear and disappear, hence the map (wikipedia).

between the two craters lies Vendelinus, an ancient crater lacking a central peak who's rounded walls and floor are covered with newer impact craters.  

Vendelinus

image details:

camera ZWO ASI 290mm IR pass filter 850

celestron 11" Edge HD, no barlow

3865 frames @59 fps 6.928 ms gain 351

5/4/22 ~3 AM UTC (5/3/22 8 pm local)

East Bluff, CA

poor seeing, IR filter helped

refs:

https://en.wikipedia.org/wiki/Petavius_(crater)

https://www.skyatnightmagazine.com/astrophotography/moon/petavius-crater/

https://en.wikipedia.org/wiki/Langrenus_(crater)

https://en.wikipedia.org/wiki/Michael_van_Langren#Contributions

https://en.wikipedia.org/wiki/Vendelinus_(crater)

sea of crisis, a lunar mare

a lunar mare (latin for sea) is a large smooth dark region on the surface of our moon.  early astronomers thought they resembled seas on the earth, hence the name.  
mare crisium caught my eye, emerging from lunar night on a 3 day old waxing crescent moon:

Mare Crisium, Sea of Crisis
5/4/2022 03:01 UTC

mare crisium is a realtively small lunar mare on the northeast quadrant of the moon.  it can be easily seen on the full moon:

mare crisium is the dark circle top
in front of the "bunny rabbit's ears"

it's the first mare to appear after the new moon, forming the "eye" of the moon's crescent:

mare crisium, the eye of the crescent upper left

lunar maria are thought to have been formed by huge asteroid impacts on the young moon which had a thin crust over hot magma.  the huge asteroids created large craters and cracked the crust.  liquid magma then flowed in--filling the craters and cooling to a smooth surface.  so at one point, they sort of were seas.  the high concentration of iron in the magma darkens the surface.  

refs:

https://lovethenightsky.com/how-did-lunar-maria-form/

https://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lola-20100702-crisium.html

https://www.glyphweb.com/esky/surface/marecrisium.html

image details:

camera ZWO ASI 290mm IR pass filter 850

celestron 11" Edge HD, no barlow

880 frames @16 fps 6.928 ms gain 351

5/4/22 ~3 AM UTC (5/3/22 8 pm local)

East Bluff, CA

poor seeing, IR filter helped

full disk

11/27/12

FS 102, SX H9 (probably)

crescent

5/26/2006

FS 102, SX H9 (probably)