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Author Topic: Kalassak's Astrophotography  (Read 20566 times)

atomic7732

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Kalassak's Astrophotography
« on: November 16, 2017, 12:18:36 AM »
most of my previous astrophotography is in the thread about my telescope and the thread about C/2014 Q2 (Lovejoy), but in the future i will (try to) post it all here



i got my Vixen Polarie (equatorial tracking mount) today and omg it's amazing

it came with a sturdy af tripod that is so much better than my old one(s) and the ball head adapter that the camera sits on is so smooth and easy to move and lock in place, even if controlling it to aim at the right place is a little weird some times

i still need to mess around with it a bit, cause my image of the Andromeda Galaxy is a flop and i can't find C/2017 O1 (ASASSN), but... i will! after i figure out optimal camera settings and stuff

on the other hand, the Orion Nebula came out well:



5x 30s @ ISO 400, 300mm, f/5 Sony alpha 58 (cropped)
« Last Edit: November 16, 2017, 12:54:06 AM by atomic7732 »

MrPuffin

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Re: Kalassak's Astrophotography
« Reply #1 on: November 16, 2017, 09:13:14 AM »
That's awesome! I'm hoping I can get a hi-tech telescope/gear like yours in the future! I'm hoping that I'll get it for Christmas and I hope I don't get one of those 20 dollar sears telescopes. I want a real one like yours! I'm hoping to be able to look at all the different planets and stuff.

atomic7732

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Re: Kalassak's Astrophotography
« Reply #2 on: November 19, 2017, 03:30:21 AM »
It's not pretty but... behold, 62P/Tsuchinshan 1 (faint fuzzball just to the right of center):



6x 30s @ ISO 6400, 300mm, f/5 Sony alpha 58 (cropped)

atomic7732

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Re: Kalassak's Astrophotography
« Reply #3 on: November 20, 2017, 03:24:56 AM »
omggggggggggggg it's greeeeen (well, cyanish)


2x 30s @ ISO 16000, 300mm, f/5 Sony alpha 58 (cropped)

not as good as it could have been, some clouds moved in and i have to go to sleep

atomic7732

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Re: Kalassak's Astrophotography
« Reply #4 on: November 22, 2017, 03:59:23 AM »
idk where the color went, also iota Leonis in the center


5x 30s @ ISO 16000, 300mm, f/5 Sony alpha 58 (full frame)

atomic7732

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Re: Kalassak's Astrophotography
« Reply #5 on: November 27, 2017, 11:21:16 AM »
Andromeda


10x 30s @ ISO 16000, 300mm, f/5 Sony alpha 58 (cropped)

atomic7732

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Re: Kalassak's Astrophotography
« Reply #6 on: November 27, 2017, 10:36:15 PM »
some asteroids


atomic7732

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Re: Kalassak's Astrophotography
« Reply #7 on: December 08, 2017, 05:09:40 AM »
new friend

24P/Schaumasse (while located near FO Virginis, the brightest star in the frame)


blotz

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Re: Kalassak's Astrophotography
« Reply #8 on: December 08, 2017, 09:23:03 PM »
aah nice one


atomic7732

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Re: Kalassak's Astrophotography
« Reply #9 on: December 14, 2017, 12:44:27 PM »
comet number 5

C/2016 R2 (PANSTARRS)


atomic7732

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Re: Kalassak's Astrophotography
« Reply #10 on: December 23, 2018, 12:40:15 AM »
46P/Wirtanen from tonight



it's quite a bit brighter than when i observed it on winter break but still pretty hard to see visually in the telescope

vh

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Re: Kalassak's Astrophotography
« Reply #11 on: December 26, 2018, 11:11:41 PM »
i'm hijacking this thread into shimao's astrophotography, hope you don't mind

my equipment is a 10 year old dslr with a telephoto lens (telescopes are for nerds) and no tracker, so my exposures are 1-2 seconds long max. also i don't know what i'm doing

here we see the orion nebula -- i think i'm going to need more than 25 seconds of exposure all combined to get a good pic


and the pleiades cluster, with hilarious amounts of chromatic abberation

atomic7732

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Re: Kalassak's Astrophotography
« Reply #12 on: December 27, 2018, 12:54:35 AM »
what is that saturation lmao, otherwise pretty good :)

on the other hand, this was a surprising post and i am pleasantly surprised i have someone else to astrophotograph with now

i mostly just use a telephoto lens and a tracker but i didn't bring either over winter break so the wirtanen pic was with my camera and telescope
« Last Edit: December 27, 2018, 03:35:53 AM by atomic7732 »

vh

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Re: Kalassak's Astrophotography
« Reply #13 on: December 31, 2018, 02:53:33 AM »
orion attempt 2



let's see how much postprocessing helps

« Last Edit: December 31, 2018, 08:19:37 AM by vh »

atomic7732

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Re: Kalassak's Astrophotography
« Reply #14 on: January 01, 2019, 04:21:11 PM »
i like the first picture better

the colors are subtle but natural

i'm no post-processing expert but i'd just try to stretch out the values so that the nebula looks a little brighter and maybe increase saturation just a bit

vh

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Re: Kalassak's Astrophotography
« Reply #15 on: January 04, 2019, 09:52:21 AM »
my complaint with v1 is that there are parts of the nebula /gas cloud which aren't visible there but which i was able to bring out in v2

atomic7732

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Re: Kalassak's Astrophotography
« Reply #16 on: January 04, 2019, 08:44:16 PM »
yeah but the bright areas are blown out and the colors are funky in v2, you're just trading one type of problem for another

atomic7732

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Re: Kalassak's Astrophotography
« Reply #17 on: April 10, 2020, 03:30:06 AM »
some low effort mode ap from winter break

shot in jpeg instead of raw cause i'm a dingbat

M79

C/2017 T2 (comet #7)

hopefully after this cutoff low passes i can get out and try to observe the three mag 7-8 comets we have right now (one of which is T2 from above, and it's brighter now)

atomic7732

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Re: Kalassak's Astrophotography
« Reply #18 on: April 11, 2020, 03:05:24 AM »
turns out the cutoff low kept its clouds back and i got to do some imaging

C/2017 T2 (PANSTARRS) 1x30s

C/2019 Y4 (ATLAS) 3x30s (also comet #8)


atomic7732

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Re: Kalassak's Astrophotography
« Reply #19 on: April 17, 2020, 03:08:27 AM »
small outburst made me go look

C/2019 Y1 (ATLAS) 6x30s and stacked to the comet so the stars are streaky (also comet #9)

atomic7732

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Re: Kalassak's Astrophotography
« Reply #20 on: July 04, 2020, 04:55:07 AM »


yeah

C/2020 F3 (NEOWISE) - comet #10

atomic7732

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Re: Kalassak's Astrophotography
« Reply #21 on: July 05, 2020, 05:21:20 AM »
the comet was more easily visible today



the tail is pretty clearly a degree or two long, and that characteristic was much more easily visible with the naked eye to me today, but maybe that's just cause i was able to see it earlier and was less focused on taking pictures of it with my camera.



here's a general guide on how to find it (pic from my phone):



look in the northeastern sky before sunrise, around 4 am (check stellarium or sth for your specific location). capella will be in the northeast and venus will be in the east. in this image, the comet is actually visible in the yellow circle, it has just risen and in this photo is about 4 degrees above the horizon. a clear horizon (or as best as you can get) will be key, since the best views will be when the sky is darkest, but this is when the comet will be the lowest in the sky (just like the sun!). it only rises to about the height of the lowest power line before it begins to get lost in the glare of the sun/sky. as you can see in this pic, i have positioned myself on one side of a main road with suburban one story houses on the opposite side, which allows me a pretty decent horizon.

the comet will be moving northwest (so, higher in the sky and closer to being straight below capella) over the next few days and will become easier to see, however it will also be dimming slowly, so i don't know. i'd go look for it whenever you can!
« Last Edit: July 05, 2020, 05:28:06 AM by atomic7732 »

atomic7732

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Re: Kalassak's Astrophotography
« Reply #22 on: July 14, 2020, 04:31:05 AM »
tried doing some stacking but as i expected it didn't really work out

this is a long exposure though, very grainy cause it's just one image



i tried stacking images manually with IRIS, but it messed with the colors so all i got was this grayscale image



it's a lot less noisy but i feel like it has less character

maybe i'll try imaging with my polarie in the coming days

atomic7732

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Re: Kalassak's Astrophotography
« Reply #23 on: July 18, 2020, 07:58:17 PM »
polarie time



13x10s

vh

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Re: Kalassak's Astrophotography
« Reply #24 on: October 31, 2020, 09:11:46 AM »
shimao hijack time

We can measure how much light we've been exposed to in units of steradian meter^2 seconds, where we multiply the time of our exposure (T), by the area of our sensor (A), by the solid angle of sky exposed to the sensor (S). Thus we can compute exposure as STA.

Typically in photography, you might also crop the image, resulting in a ratio of cropped image area to original image area of K. Since the crop affects both sensor area and sky angle by a multiplicative factor, thus we get STAK^2

The solid angle of sky can be related to the focal length (F) and the sensor area with a small angle approximation: S = A/F^2, so we prefer the formula T(AK/F)^2

Example: I made 14 exposures of 15 seconds each with my camera (366.6 mm^2 sensor), a crop ratio of roughly (3/8), and a focal length of 200mm. This comes out to 100 micro sr*m^2*s

If you're confused, here's some intuition: Screen brightness is often measured in nits, where something like 200 nits is a fairly average monitor brightness. It turns out that sr*m^2*s = joule/nit, so if you think of the sky as a really dim and faraway monitor (let's say 0.01 nits), then an exposure of 100 micro joule/nit * (1/100) nits means our sensor was exposed to a microjoule of light energy. If we knew the exact wavelength of light, we could even go further and compute the number of photons per pixel or something like that.

Anyway, since micro sr*m^2*s is annoying to write out, and joule/nit is more intuitive, I propose calling this "ujpn" for "micro joules per nit". This below photograph was taken at an exposure level of 100 ujpn.


vh

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Re: Kalassak's Astrophotography
« Reply #25 on: October 31, 2020, 09:17:53 AM »
oops, i just realized it's probably the lens aperture that matters and not the sensor size (although the ratio of the sensor area to the total area the lens projects the image on needs to be factored in). so ignore everything above until i fix the math. although the units won't change and i still think ujpn is a pretty cool unit

atomic7732

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Re: Kalassak's Astrophotography
« Reply #26 on: January 12, 2021, 01:19:57 AM »
from when i went camping last month

C/2020 M3 (ATLAS) - comet #11



9x15s

156P/Russell-LINEAR - comet #12



also 9x15s

i took some other pics too, those still need to be processed
« Last Edit: January 12, 2021, 07:57:58 PM by atomic7732 »

WitheHole18

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Re: Kalassak's Astrophotography
« Reply #27 on: January 21, 2021, 12:08:53 PM »
Orion Nebula here