Author Topic: International Space Station fun  (Read 198 times)

beryllium10

  • NG Member
  • *
  • Posts: 248
International Space Station fun
« on: May 26, 2021, 05:40:55 »
About this time of year we usually get a few nights of clear weather combined with very bright passes of the International Space Station.  A couple of weeks ago we had a good one that peaked at magnitude -3.8 (explanation below).  That's bright enough to photograph at 1/2000 sec at a reasonable aperture and ISO.  I tried this a couple of years ago with the 300mm f/4 and a TC1.4 and was pleased to see obvious structure - more than just a bright dot.  This time I repeated the attempt with a 500 mm PF, which gave even more remarkable results.  The ISS photos below are from one frame that includes the star Arcturus for reference.  Taken wide open at f/5.6, 1/2000th, ISO640.  It feels comical pointing a long lens up into the dark sky and snapping away at 1/2000th sec.
In order, the photos are:
(i) Full D850 frame downsampled ~5X to 1600 x 1067.  The ISS is the 3x5 pixel speck left of center, Arcturus is a single pixel down and right.
(ii) Downsampled 2X and cropped to 1600 px to include the ISS and Arcturus.  You can begin to see some detail.   
(iii) Small 100% crop of the ISS. 
(iv) Reference 100% crop of the Moon, photographed and processed with all the same settings.
All pushed one stop, lightly sharpened in ACR and converted to jpeg without further sharpening.  I also removed some red-green fringing in ACR, which I think was atmospheric, not due to the lens. 
At this point in its orbit the station is about 495 km away.  It's 73 x 109 m.  So this is like trying to photograph the Eiffel Tower from Amsterdam, only the space station is smaller.
Cheers,  John

Note - astronomical magnitudes:  Apologies to astronomers, but this scale is nuts:  It's logarithmic, 5 magnitudes equals a factor of 100 in brightness, and back to front - negative numbers mean bright! (https://en.wikipedia.org/wiki/Apparent_magnitude).  Anyway, -3.8 is brighter than Jupiter, almost as bright as Venus. 

Øivind Tøien

  • NG Member
  • *
  • Posts: 1389
  • Fairbanks, Alaska
Re: International Space Station fun
« Reply #1 on: May 26, 2021, 06:02:58 »

Well done and fun exercise!

May be try a pass in front of the moon next time.  ;)

(Yes, I have tried and miserably failed even getting the right time...)
Øivind Tøien

Jakov Minić

  • Jakov Minic
  • Global Moderator
  • **
  • Posts: 5176
  • The Hague, The Netherlands
    • Jakov Minić
Re: International Space Station fun
« Reply #2 on: May 26, 2021, 09:52:50 »
It looks impressive. Haven't seen photos of the international space station taken from Earth before.
Free your mind and your ass will follow. - George Clinton
Before I jump like monkey give me banana. - Fela Kuti
Confidence is what you have before you understand the problem. - Woody Allen

Akira

  • Homo jezoensis
  • NG Supporter
  • **
  • Posts: 10639
  • Tokyo, Japan
Re: International Space Station fun
« Reply #3 on: May 26, 2021, 12:09:31 »
Nice one, John!  Well worth trying!
"The eye is blind if the mind is absent." - Confucius

"Limitation is inspiration." - Akira

Nasos Kosmas

  • NG Supporter
  • **
  • Posts: 573
  • Athens, Greece
Re: International Space Station fun
« Reply #4 on: May 26, 2021, 15:31:02 »
Yeah! I am impressed !
Good job John, where are you located and got these photos?

beryllium10

  • NG Member
  • *
  • Posts: 248
Re: International Space Station fun
« Reply #5 on: May 26, 2021, 16:59:22 »
Thanks all!  Øivind - I've actually been searching for a future pass close to the Moon.  It would be fun to make a composite image from a sequence of frames using the Moon to align them.  There were a couple in the middle of the month that passed within 2-3 degrees, but both nights were cloudy.  Two nights ago there was a pass close to Alkaid, in Ursa Major.  Again cloudy.  It's late May, but we have descended into our customary "June gloom" - the eclipse last night started in clear skies but disappeared behind cloud.  Nasos - these are from Seattle, where stargazing requires a fair bit of luck and patience (and the seeing is often unstable even when the skies are clear).
Cheers again,  John