Try increasing gamma if dark sections aren't distinguished

Try increasing gamma if dark sections aren't distinguished

Wednesday, August 22, 2018

fisheye perseids, star trails, and galactic fun

A fisheye lens is an ultra wide angle lens that can view the entire sky at once, but with strong visual distortions at the edges (straight lines become curved).  originally developed for meteorology (weather, not meteors), astronomers have taken them up for...meteors, not weather.  the wide view allows the camera to capture shooting stars anywhere in the sky.

so just for fun, on the evening of the Perseid meteor shower, i aimed a video camera (which came with a stock fisheye lens) at the sky and recorded images all night long.  bear in mind that my skies are extremely light polluted: the milky way is not visible and only the brightest stars of constellations can be seen most nights.  The situation was worsened by recent forest fires.

individual perseids:
over 7 hours (until clouds rolled) i only caught 4 bright meteor trails that would have been easily visible in my skies (and a hundred airplanes).  The first, and brightest, occurred at just after midnight:
Perseid meteor 8/13/2018 12:11 AM PDT
faint doted line mid frame is an airplane

Here's a blink of all 4 processed to remove light pollution/sky glow and bring out the stars:
meteors at 12:11 AM, 1:08 AM, 2:55 AM, and 3:50 AM PDT. 
clouds rolled in at 4 AM, peak viewing time :(
a mosaic combining the images of each:
4 perseids and an airplane
can you find cassiopeia, perseus? 
pleiades? andromeda galaxy?

here's a cropped version with the pertinent constellations outlined:
note that, allowing for fisheye lens distortion, they all point to Perseus.   

and yes that faint white band in the middle of the image is the milky way:  
180 x 20 second frames aligned on our galaxy
cleaner crop:

another cool thing you can do with a fisheye lens is wide field star trails: shooting pictures of the sky all night long on a tripod will demonstrate the rotation of the stars across the sky, centered around the northern celestial pole.  though my camera chip isn't big enough to capture the entire sky in one image, the diagonal will reach all the way from polaris in the north to mars skimming the southern horizon:
note polaris (lower left) rotating slightly around the north celestial pole and a bright perseid to it's right. 
the thick bright trail (top right) is mars on the southern horizon.
the gaps result from pauses writing to disk and removal of frames with airplanes :(

a version with the air traffic upstaging the perseids
(slight shift in the camera position):
The bright trail just inside mars (upper right) is saturn
here's a mesmerizing video showing the progress of the star trails:

selfie/warm-up from the night before:
star trails 8/12/2018
can you see my T-shirt and blurred head moving thru a long exposure?
dark shirt next time

clouded out at the end, so i guess this is true meteorology:

apparently aristotle considered anything falling from the sky: rain, snow, sleet, hail, rocks, fireballs, hellfire...a meteor, hence the confusion.

image details:
stock fisheye lens with home made cardboard dew shield and kendrick dew heater
Gain=100 (16%)
20 second exposures continuously from
9 PM 8/12/18 to 4 AM 8/13/18 AM PDT (until clouded out)
Southern California

processing the mosaic and milky way image was challenging due to the distortions at the edge of the fisheye lens and significant light pollution gradients.
maxim was not up to the task, so i resorted to registar which did an amazing job aligning/warping images for the combined shots.

i had no flats, so used the hubble trick, creating flat via a median combine of 1000 different light frames giving a smooth background without stars to correct the uneven illumination of the fisheye:
median combine of all images
still limited by heavy gradients liberal use of photoshop including gradient xterminator was required.

Thursday, August 9, 2018

martian mountains

recent mars images:
Mars 8/7/2018 07:45 UTC RGB
CM = 84.9
CL = -10.0
Infrared as luminance:
Mars 8/7/2018 07:45 UTC IR-RGB
with more heavy handed processing in my latest image Olympus Mons, one of the tallest mountain in the solar system, can be seen thru the dust.  
Olympus Mons
Mars 8/7/2018 07:45 UTC RGB

Though less distinct, three mountains of the Tharsis range can also be seen:
Tharsis Montes
Mars 8/7/2018 07:45 UTC RGB
Mount Olympus can also be seen in this image a few days earlier, though less clearly.  
Mars/Olympus Mons 8/4/2018 08:45 UTC IR-RGB
CM = 126.2
CL = -10.2

Mars 8/4/2018 08:14-08:50 UTC IR
Imaging details:
reviewed prior images while there seems to be a slight increase in contrast, my processing has become more heavy handing, yielding more details; it's still pretty much a featureless orange disk with a polar cap visually.
8/4/2018 08:45 UTC
CM = 126.2
CL = -10.2
8/7/2018 07:45 UTC
CM = 84.9
CL = -10.0
celestron 11" Edge HD
televue 2x barlow
ZWO RGB filters, Baader IR pass "685" nm
8/4 4x120 seconds
8/7 2x120 second captures each filter 8/7
200 FPS, gain 351, exposure ~1 ms (3 ms blue), 30% histogram
firecapture, autostakkert, winjupos, maxim, photoshop
elevation 30 degrees
Southern California

Tuesday, July 31, 2018

Mars closest approach 7/31/2018

Here's mars at closest approach for the 2018 opposition:
Mars 7/31/18 8:21 UTC
Visually it looked like a bright orange disk with poles visible.  seeing was not great, but Cassini was easily resolved on Saturn, so assuming the lack of contrast/detail is the dust storm.  

An IR filter cut thru the dust bringing out more detail on the face:
Mars 7/31/18 8:21 UTC IR
Lastly, here's the RGB color with IR applied as luminance:
Mars 7/31/18 8:21 UTC IR-RGB
For reference, here are the individual color channels.  note the high contrast polar caps in the blue:

Image details:
7/31/18 08:07-08:35 UTC
celestron 11" Edge HD
televue 2x barlow
ZWO RGB filters, Baader IR pass "685" nm
2x120 second captures each filter, 200 FPS
gain 351, exposure ~1 ms (3 ms blue), 30% histogram
firecapture, autostakkert, winjupos, maxim, photoshop
elevation 30 degrees
Southern California

Sunday, July 29, 2018

mercury take 2

mercury, is difficult to observe and image.  since it's so close to the sun, it is usually only seen low in the horizon just before or after sunset.  visually, mercury looks like a tiny orange half moon.  the reddening results from atmospheric diffraction, due to its low position in the sky. 
more info at prior blog on mecury

in my recent imaging session, with mercury relatively high in the sky (thanks to a computerized mount and my house blocking the sun), it appeared to be a white partial disk.  some have been able to demonstrate surface detail on mercury with IR filters (which are less subject to atmospheric seeing effects).  unfortunately, i was not able to pull out any detail, but i did get a nice sharp half moon 😃. 

Mercury 7/15/2018 IR 2:23 UTC
with a lot of imagination, there may be a slight blotch to the right, but i'm keeping "detail on mercury" as a future project.  opportunities at dusk occur when it is furthest from the sun: ~November 6 2018, next February 27 or June 23 2019.

a few more images:
Mercury 7/4/2018 IR 3:14 UTC
Mercury 7/3/18 (red filter) 3:15 UTC
here's my 2006 effort low on the horizon, barely visible as an orange dot:
Mercury 10/19/2006

Imaging details:
Celestron 11 edge HD
Camera=ZWO ASI290MM
4x5 minute captures
~400 fps
best .25% of ~500,000 frames
Shutter=0.1 ms
Gain=361 (60%)
Baader IR pass "685" nm
2x barlow and
upsampled 2x

Southern California

Sunday, July 22, 2018

Jumpin' Jupiters

Had a run of the best seeing I've ever experienced in my location during the unusually warm humid weather of June and early July this year.  Here are a bunch of Jupiter images and some comments on imaging techniques during the session.

C8 2x barlowed with mono camera.  though shot on a different night, it suggest a dramatic improvement imaging with the barlow compared to a recent image without the barlow (prior post):
6/11/18 04:25 UTC

C 11 first light, poor collimation (compounded by fogging of filters i think) left large offset halos requiring much work in photoshop for removal 
wound up getting fogged out so not all color was captured, but was clearly able to demonstrate better detail in 2x barlowed images compared to 1x upsampled.
2x barlow gave greater than 2x magnification:
6/25/18 04:47 UTC upsampled 2x
do not click for full size
6/25/18 04:47 UTC 2x barlow
do not click for full size

collimated C 11 getting better:
6/26/18 04:46 UTC
click for full size
6/27/18 06:32 UTC
click for full size

7/2/18 05:53 UTC
click for full size
um, the seeing was very good on 7/2-3:
7/3/18 04:32 UTC
seeing party over 😞 (still as good as captures from last year):
7/4/18 07:19 UTC
seeing encore:
7/14/18 05:08 UTCclick for full size

On the new scope:
celestron edge HD 11
11" aperture, FL 280 mm (f/10)
3.75 inch central obstruction (34%)
28 lb
tempest equilibration fans installed

why not the meade 12?
also a good scope, better focuser, bigger aperture, though 13 lbs. heavier. 
It didn't play well with my persnickety ASA mount.  in particular cool down requires opening up the back and/or placing a cat cooler in the scope, leading to weight imbalance causing the motors to let go, or requiring the use of a hex wrench to lock the mount in a recessed socket under the the dark. 

imaging conclusions:
1. it's 90% seeing (second best image was barlowed c8)
2. barlow makes a noticeable difference in many different circumstances despite increasing exposure length and decreasing fps
3. venting tube currents seems necessary for the large SCT's.
4. mono noticeable improvement over color
5. stacking up to 18 minutes smoother than 9
6. preliminary stack/rejection and centering batch mode in PIPP speeds up processing and seemed to center slightly better than direct to autostakkert, improving winJupos work flow (thanks sam)
7. wide field with moons very helpful for size/rotation determination, even for jupiter in winjupos
8. sharpening before or after winjupos combine made no difference given the same alignment

issues: still getting some variability in size/placement in winjupos
refocusing between filters seemed to help.  check with bahtinov mask

Imaging details:
camera ZWO ASI 290MM with ZWO RGB filters

celestron nexstar 8 GPS (8" SCT on a wedge)
televue 2x barlow
~70 sec captures, 2 each filter
gain 351, exposure ~5-9.4ms, 30% histogram, ~90 fps
drizzle 1.5x

celestron 11" Edge HD
60 second captures 2 each filter with and without televue 2x barlow
gain 351, exposure ~0.6-1ms, 30% histogram, ~200 fps
barlowed 3-5ms ~147 fps
fogged out, poor collimation
barlowed vs resample 2x

celestron 11" Edge HD
60 second captures 2 each filter
gain 351, exposure ~0.6-1ms, 30% histogram, ~287 fps
resample 2x

celestron 11" Edge HD
televue 2x barlow
90 second captures 2 each filter
gain 351, exposure ~3-6ms, 30% histogram, ~150 fps
drizzle 1.5x

celestron 11" Edge HD
televue 2x barlow
90 second captures 2 each filter
gain 351, exposure ~3-6ms, 30% histogram, ~150 fps
resample 2x

celestron 11" Edge HD
televue 2x barlow
90 second captures 3 each filter
gain 351, exposure ~3-5.7ms, 30% histogram, ~130 fps
drizzle 1.5x

celestron 11" Edge HD
90 second captures 2 each filter
gain 351, exposure ~.5-1.8ms, 30% histogram, ~200 fps
drizzle 3x, then reduced to 1x :(

celestron 11" Edge HD
televue 2x barlow
90 second captures 4 each filter (18 min)
gain 361, exposure ~3-5 ms, 30% histogram, ~150 fps

Southern California

Monday, July 16, 2018

conjunction junction venus and luna

conjunction: two astronomical objects coming together.

disclaimer: i'm not much on terrestrial photography and my DSLR battery died as i focused, so cell phone, point and shoot and lots of photoshop. enough excuses...

artsy composition thru trees (see the earthshine?):

California sky, with palm tree, pink clouds, airplane and low smog:

OK back to astrophotography

venus and moon during twilight (which or course didn't fit in the same telescopic field) photoshopped together:

Ultra Venus:

Imaging details:

venus and moon
7/15/18 03:18 UTC
Celestron 11 edge HD
Camera=ZWO ASI290MM
venus with
Baader U filter: 350nm, bandwidth 60nm (320-380nm)

7/15/18 8:40-9:20 PM pacific
wide view
cell phone, Droid Turbo
tree view
Sony DSC-RX100M3
f/2.8, iso 6400 26 mm

Southern California

Sunday, July 15, 2018


While you may have read some of the hype surrounding the most favorable Mars viewing since the 2003 opposition (which helped inspire my interest in astronomy), there's a less encouraging story surrounding Mars recently.  
Recall Mars is the only planet in the solar system who's surface detail can be seen telescopically, and that Mars is only in a favorable position for viewing from earth every 2 years (26 months).  More on Mars in my 2013 blog entry
Unfortunately, what started as a small dust storm on a portion of the surface has evolved into one of the largest dust storms in recorded history, completely obscuring surface detail for the last few weeks.  While planetologists find this fascinating, it's a bummer for amateur astronomers, as all that can be seen is a featureless orange disk.  

Here's an image of mars from 2005.  The snaky white structure just right of center is a dust storm:
Mars 10/19/05 08:00 UTC
Here's my first image of mars this year.  The entire surface is obscured by dust, you can see a hint of blue surface structure and polar caps:
Mars 7/14/18 08:00 UTC
An infrared image cuts thru some of the storm, showing a bit better contrast:
Mars 7/14/18 08:00 UTC, infrared

Consider the fate of a manned Mars mission dependent on solar power during a month long planet-wide storm...Potato!

Some nice before and after images can be seen in this sky & telescope article

Nevertheless, the storm seems to be lessening, so there may be more to see during opposition on 7/23/18. 

Image details:
10/19/05 08:00 UTC
nexstar 8 gps, 2.5x powermate
toucam pro ii
1/500 exposure 3000 frames
Los Alamitos, CA

7/14/18 08:00 UTC
celestron 11" Edge HD
televue 2x barlow
zwo RGB filters, Baader IR pass "685" nm
90 second captures each filter, 200 FPS
gain 361, exposure ~1 ms (3 ms blue), 30% histogram
elevation 30 degrees
Southern California

Saturday, July 14, 2018

Ultra Venus

Venus is covered by a thick layer of clouds which shines brightly, making it the brightest planet in the sky.  See prior Venus overview.  Visually it appears to be a featureless white disk which goes thru phases like the moon.  However, UltraViolet light shows rapidly moving clouds, thought to be composed of sulfuric acid and aerosols(wikipedia):  

Venus Visible light 7/3/2018 ~3:30 UTC

Venus Ultraviolet colorized 7/3/2018 ~3:30 UTC

Venus Ultraviolet grey scale 7/3/2018 ~3:30 UTC

Venus Ultraviolet 7/2/2018 ~3:30 UT
Venus Ultraviolet 7/14/2018 3:35 UT
Venus Ultraviolet colorized  7/14/2018 3:35 UT

No detail in this one:
Venus Ultraviolet 7/4/2018 ~3:30 UT

Couldn't pick up any detail in IR:
Venus Infrared 7/3/2018 ~3:30 UTC

Imaging details:
imaging in UV was complicated by light loss and poor focusing of UV light by glass elements in the image train, increased UV susceptibility to atmospheric distortion, and turbulent air near sunset when Venus is visible.
typical capture
Celestron 11 edge HD
Camera=ZWO ASI290MM
Frames captured=109386
FPS (avg.)=272
Gain=361 (60%)
Baader U filter: 350nm, bandwidth 60nm (320-380nm)
Baader IR pass "685" nm

Southern California