Try increasing gamma if dark sections aren't distinguished

Try increasing gamma if dark sections aren't distinguished

Tuesday, August 25, 2020

a perseid

back in eastbluff i decided to try out my D850 on the perseids on 8/11/20.  an extremely bright meteor streaked like lighting across the sky as i set up my camera at round 10 or 11 pm...only caught one with the camera over the next 3 hours:

Perseid 8/11/2020



close up





image details:
8/11/20, eastbluff, CA
nikon D850
Sigma 15mm F/5 EX DG fisheye
30 sec, iso 200
focusing the D850 with live view zoomed in and super high iso was a joy, giving tight stars on close up (though distorted by the fisheye) compared to the D60

this contrasts with my dark sky neowise images with twice the aperture and 100x greater ISO.  the image would be solid white if i tried that under polluted skies.  

Saturday, August 22, 2020

our galaxy

the milky way has been on my to do list for a while. here's a shot from the desert:

Milky Way 7/21/2020, Sheep Hole Valley Wilderness,  Mojave Desert


my best to date, though somewhat anticlimactic as it was a 20 second afterthought while shooting comet neowise

another edge on galaxy for comparison:

NGC 3628 35 million light years away
2007

previous attempts:
Hetch Hetchy, stacked images, dark skies old out of focus DSLR
2019


wide field stack from light polluted skies
2018 webcam


first ever 2004.  the faint "smoke" coming out of the chimney is the milky way, totally by accident






image details:
sheep hole valley wilderness, mojave desert, CA
7/21/20 10:00 PM pacific
nikon D850
wide field: Sigma 15mm F2.8 EX DG fisheye
20 sec ISO 25,600

NGC 3628
4/12-17/07
los alamitos, CA
N8 GPS, F/6.3 FR @~1280mm, SX AO @~4Hz, IDAS LPR, H9C
45x20 minutes

7/7/19 
Hetch Hetchy, Yosemite National Park, California
Nikon D60
stock lens (18-55) @18 mm f/3.5
sky watcher star adventurer mount (tracking stars)
88x30 sec ISO 400
even with dark subtraction, there was significant amp glow, hence the desaturation.

8/12/18 to 4 AM 8/13/18 AM PDT (until clouded out)
Eastbluff
Southern California
ZWO ASI 290MC
stock fisheye lens with home made cardboard dew shield and kendrick dew heater
Shutter=20.0s
Gain=100 (16%)
20 second exposures continuously

2004
Canon digital rebel
stock lens

Sunday, August 16, 2020

NEOWISE C/2020 F3 from the desert

Here are my NEOWISE images from the Mojave.
First, a starlink photobomb (a/k/a) Elon plays space invaders:
comet NEOWISE C/2020 F3 animation, series of 3 second exposures 7/21/20


close up stacked image (removing star, comet, satellite and plane trails):



wider view with a bonus early perseid:

still wider (fisheye):

Thanks to OC astronomers member and renowned astrophotographer Wally Pacholka for the inspiration:
"Gents With a comet like Neowise dropping by only every 20 years or so, can I encourage folk to see and photograph it from a dark location so you can enjoy it’s true beauty. Do whatever is necessary to leave Dodge and get out of town."
his NEOWISE images are available here:

Observations/Travelogue 
taking a tip from wally, i headed out to amboy crater, in the Mojave desert 
Amboy Crater

an ideal location due to the absence of light pollution in the northwest where the comet would be setting:
after a bit of reconnoitering, i opted for a location a bit south of the crater then made a few minor adjustments for local wild life:
snake spoor
 
visually, the comet was spectacular, spanning 5 degrees of sky (10 degrees with binoculars) almost as bright as the milky way, though more focal.  

photographically, saturday night (7/18/20) was a bust.  it seemed my 10 year old nikon D 60 which was fine in light polluted skies was not up to dark skies in 100 degree heat (but it was dry heat)

A rare case where the camera is less sensitive than the eye (or cellphone):
Nikon D60 stacked and processed

cellphone:
Samsung Galaxy Note 9 single frame

having flailed with my Nikon D60 Saturday night, i went back out to the desert Tuesday night to try again, armed with a better camera (rented nikon D850) and more glass. 
 
This time at the sheep hole valley wilderness (south east of amboy) just north of eastern joshua tree.  
the sheep hole mountains on the left of the widefield are shielding the barstow (and 29 palms) light dome which i assume can be seen from much of joshua tree when looking NW:



Image details:
sheep hole valley wilderness, mojave desert, CA
7/21/20 ~9:20-11 PM pacific
nikon D850
close up AF-S NIKKOR 85mm 1:1.4G 
10x stack 3 seconds ISO 25,600!
stacked in deep sky stacker
intermediate: AF-S NIKKOR 18-55mm 1:3.5-5.6G at 18 mm
30 sec ISO 25,600
wide field: Sigma 15mm F2.8 EX DG fisheye
20 sec ISO 25,600
lens distortion correction in photoshop

spent too much time stacking images which wound up worse than single shot except for the close up.  
super high ISO, blew out the star colors, but stacking with lower ISO images didn't work out for me.  
NEOWISE 7/21/20 5 sec ISO 6400, better star color and green at comet core



Sunday, July 12, 2020

comet NEOWISE C/2020 F3

Here it is over Irvine from my house (click for full size):
Comet NEOWISE C/2020 F3 over Irvine 7/12/2020

Comet NEOWISE C/2020 F3 7/12/2020

Comet NEOWISE C/2020 F3 7/12/2020

Observations:
the comet was not visible to the unaided eye.  the contrast in binoculars about matched the wide field image (canon 15x50 IS).  it started fading markedly at 5:00 AM and was lost to view at 5:15 AM

image details:
after days of getting up painfully early to clouds, i caught it this morning.  the sting of the early rise was mitigated by the fact that the 10 degree arc of horizon visible from my bedroom balcony aligned perfectly with the comet.
Nikon D-60, AF-S DX NIKKOR 55-300mm f/4.5-5.6G ED VR, 
wide: f/4.5 @ 55 mm, ISO 800, 3.0 sec, 4:58 AM
narrow: f/5.6 @ 300 mm, ISO 800, 3.0 sec, 4:43 AM
7/12/2020
Eastbluff, CA  

Thursday, March 12, 2020

The fainting of Betelgeuse

Will Betelgeuse blow? Will Taurus gore Orion? Read below:

Recently, the star Betelgeuse (orange "shoulder" of Orion) faded from the 10th brightest in the sky to about 26th.  No longer a beacon, it faded almost to the level of Orion's belt, and well below the level of blue Rigel (Orion's forward foot).  This is the most faint ever recorded (observes have been tracking it with the use of reference stars for ~200 years).  Many in the astronomy field were excited by this as it might be the harbinger of a supernova in our "back yard", an event not witnessed in living memory.

The relatively dark image of orion below was processed to preserve relative brightness and color.  you may need to darken the room and/or adjust your monitor to see it well.  pretend you're looking at stars...
Orion linear stretch to preserve relative brightness.  Note that orange Betelgeuse (upper left)  is closer to the brightness of the belt stars,than bright Rigel (lower right)


stretched version showing orion nebula in the sword below the belt

Here's my last attempt from 2005. Is Betelgeuse brighter?

full constellation just for fun (2/26/2020)


If Betelgeuse were to go supernova, it would likely be so bright it would be easily visible during the day.  It might eventually leave Orion's shoulder with a blood red nebula the size of the full moon: as if Taurus' horn gored Orion's shoulder (Pamela Gay, Astronomycast).

Why might this happen?  Betelgeuse is a cool red supergiant star (diameter the size of Jupiter's orbit) who's brightness varies periodically with time.  The variation in brightness is due to change in the actual size of the star. For reasons not entirely clear, the star periodically shrinks and expands, creating a smaller or larger surface from which light shines.

The thing about supergiant stars is that they are known to go supernova.  They "burn" (fuse elements) so fast, that they eventually run out of fuel (actually they fuse elements up to the size of iron which doesn't like to fuse and stops the process).  When that happens, the light pressure holding the stellar surface out disappears and the star gravitationally collapses until...BAM supernova leaving a tiny neutron star in the center (like the crab nebula).

So perhaps the fainting was due to a pre-supernova collapse...
To the dismay of some, Betelgeuse began to brighten again in late February 2020.  A Spectrographic study indicated that the dimming was due to intervening dust expelled from the star.  
Addendum: Subsequent work suggested it was giant sunspots instead...

a few more gems in orion:
Orion Nebula (Ha-OIII) (1/2009) Click for full size

Flame nebula in orion with belt star alnitak blazing away (12/2006)

Horsehead nebula-blue glare left caused by Alnitak (off frame) in orion's belt. (HaLRGB 12/2007)
image details:
Orion constellation
Nikon D60
stock lens (18-55) @36 mm f/5.3
12 x 5 sec
Eastbluff, CA 2/26/2020

2005
Canon Digital Rebel 300d
stock lens

Orion nebula
FS60C f/4.2 FR Baader 8.5 nm Oiii/CS 10 nm Ha filters, H9
Ha 35x5 min + 26x30 sec, Oiii 29x5 min +33x30 sec
12/5,8,9/2008
los alamitos, CA bortle white skies
poor seeing fair transparency for area

Flame nebula
fs102 idas LPR H9C
30x5 min
it was tough controlling alnitak in processing
12/2006
los alamitos, CA bortle white skies

Horsehead nebula
FS 102 @~f/6 (618mm) with TOA reducer; IDAS LPR, CS 10 nm HA; h9/h9c; guiding with toucam on celestron f/5 80mm wideview.
rgb 83x5 min, luminance 66x2 min, HA 19x20 min
12/10-16/2007; los alamitos, CA; usual bortle white skies; several nights of above average transparency (for the region); fair to poor seeing HFD 3.8-4.7

Sunday, December 15, 2019

A black hole on Neptune?

You'd think it would be on uranus, but there's a black hole on neptune: the Great Dark Spot is thought to be related to a storm, similar to the persistent great red spot on jupiter. there's also occasional cloud activity on the surface of neptune.  both are extremely difficult to detect as it's quite distant.  

Here's a shot of neptune on the same night i shot uranus, using the same processing techniques.  
Definitely a bit of a stretch, but with a little imagination you can see a subtle dark section in the center and a white patch just below and to the right:
Neptune 10/27/2018 06:17 UTC IR-RGB
also seen to the lower right is neptune's moon triton.  

I'd say the white patch is more convincing, but can't call either more than wishful thinking/artifact at this point.  If nothing else, it's a nice shade of blue ;)



Imaging details:
camera ZWO ASI 290MM with ZWO RGB filters
Baader IR pass 685 nm
celestron 11" Edge HD
East Bluff, CA
10/27/18 06:17 UTC
120 second captures, 2x each filter (3 for IR)
gain 456 , exposure ~51 ms red, 19 ms green, 23 ms blue, 100 ms IR 685 <30% histogram
upsampled x2 in autostakkert, derotated in winjupos.
color balance on triton
composite image to bring in triton (present even on short exposures, but faint)

Sunday, December 8, 2019

clouds on uranus

what better follow up to methane on jupiter than clouds on uranus? 

prior blog entry: "there's not much to see visually.  bluish-green, it can be seen with the unaided eye in dark locations.  At high power it can be seen as a small disk rather than a dot.  A monster telescope or camera might detect several moons, and possibly faint cloud formations..."

to my surprise, an IR filter was able to bring out cloud cover on the upper half:
Uranus IR-RGB 10/27/2018 08:52 UTC
have to try a methane filter on this one ;)



Imaging details:
camera ZWO ASI 290MM with ZWO RGB filters
Baader IR pass 685 nm, Astronomik IR pass 807 nm
celestron 11" Edge HD
East Bluff, CA
10/27/18 8:52 UTC
120 second captures, 2x each filter (only one for IR 685)
gain 456 , exposure ~13 ms red, 4 ms green, 6 ms blue, 130 ms IR 807 30% histogram
upsampled x2 in autostakkert, derotated in winjupos.
color balance eyeballed ;)
(actually set the white point to the clouds)


here's the straight RGB for the purists:
Uranus RGB 10/27/2018 08:52 UTC


References:
interesting articles by Christophe Pellier on the spectrum of uranus and implications for IR filters:
https://www.planetary-astronomy-and-imaging.com/en/uranus-spectrum-commented
https://www.planetary-astronomy-and-imaging.com/en/filters-uranus-spectroscopy