Astro Photo Op

Discussion in 'Casual Photo Conversations' started by Sandy Vongries, Jun 11, 2019.

  1. Sandy Vongries

    Sandy Vongries Administrator Staff Member

  2. All four Galilean moons were visible last night, one of the few clear nights this year in Chicago. The fourth moon is just visible at the limb of the planet. Jupiter is too bright to see both the bands and the moons. I didn't take time to set up a sidereal drive, so this was taken at 1/60, ISO 25,600, then cropped

    Sony A7Riii + 105 mm x 1300 mm Maksutov reflector
    _7R35533.jpg
     
  3. Thanks for the tip.

    Our forecast is for "partly cloudy" so we shall see.
     
  4. Sandy Vongries

    Sandy Vongries Administrator Staff Member

    Nearly every one of these I've posted, I've had clouds or worse!
     
  5. Yesterday night, when I looked up at the sky, Jupiter was unmistakable, bright almost like Venus.
     
  6. Same telescope as Ed Ingold, looking out my window overlooking Lake Michigan, far north side of Chicago. ISO 12,800 @ 1/6 second. I could see bands on Jupiter, just barely, but I have way too much movement in the photo. 1300mm telescope and 2X Barlow lens, Canon SL1, cropped also. Jupiter and moons.jpg
     
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  7. Oops, not the same telescope Ed Ingold used for his shot. Mine was taken at 9:45 pm and the moons are in different locations.
     
  8. I don't have a telescope, but I gave it a shot (actually, several shots with different exposures). Here's the best I could get, using an Olympus E-M1 with an old Vivitar 120-600mm zoom at 600mm and Viltrox NF-M43 0.71x mount adapter, set to ISO 200, 1.6 seconds, f/16. This photo is heavily cropped and had a hot pixel cloned out. EM1S0277.jpg
     
  9. There is no need to use f/16. You need a compelling reason to stop down smaller than the maximum aperture for astrophotography (e.g., coma or corner resolution). With the apparent magnification above (about 25x), there is significant motion in 1.6 seconds, enough to blur the tiny moons into the background. The longest shutter time , without tracking, is typically given as 500/FL, which would be about 1/4" to 1/2" at this magnificaiton. Even that "rule" only works for star patterns, where the details aren't as important.

    I also question the use of an adapter which reduces the magnification of the lens, ostensibly increasing the relative aperture. In general, for astrophotography, the fewer optical components, the better. Plain, non-optical adapters will produce better results, and are relatively inexpensive. In this situation, magnification of the 150-600 lens would be 50% greater without the .71x adapter, and for planetary viewing, the more (clean) magnification, the better.

    For the enthusiasts, a catadioptric (e.g., Maksutov) telescope doesn't do as well as a plain refractor for planetary viewing. I can see several of Jupiter's bands clearly with a 20x60 spotting scope, but not even when squinting with the 4" Maksutov telescope at 80x. Reflectors are best used gathering sparse photons from deep space objects. Large, bright objects are subject to "doughnut-hole" distortion. If the weather holds, I will try using a ND filter by eye, and even shorter shutter speeds for photography. The Sony A7Riii exhibits little objectionable noise, even at the ridiculous speed of ISO 25,600. Long exposure noise reduction is turned off, since it confuses stars with noise, and "eats" them in the process.
     
  10. I went out, but too hazy and cloudy here. Congratulations to those who got their shot!
     
  11. Jupiter takes 12 years to orbit the sun. It will be prominently visible for several weeks.
     
  12. Ed, thanks for the tips. I may give it another go depending on the weather. As you can tell, this was the first time I tried anything like this. The exposure settings were arrived at by simple trial and error and a lot of fumbling around in the dark. The shutter speed I could see on the camera's LCD (and in the exif) but the aperture was a rough guess and may well not be correctly stated. The main challenge is that Jupiter is too bright and blows out with enough exposure to show the moons. I started with the lens wide open, and then kept stopping down until Jupiter wasn't so blown out, then I started changing the shutter speed to try to get the moons to show up again but with my one track mind I totally forgot I could open up the aperture again. On my computer monitor at home, the moons in my photo are much more visible than they are when I look at them now on my office computer.

    The 0.71x lens adapter was used because that's the only one I have, although in retrospect I should have just used the lens mounted directly on one of my DX-format Nikons. My excuse is that my knees are too old to be crouching behind a tripod anymore, the flip out LCD on the Olympus made things much more comfortable.
     
  13. Of course. I shall try again.
     
  14. You learn from your mistakes, and if my suggestions help, it is because I've made a lot of them on my own.

    Next time, I'm going to try bracketing exposures and combining (stacking) the results. There should be a way to do that with manual exposure, since AE is totally useless.
     
  15. Tony Parsons

    Tony Parsons Norfolk and Good

    I'm in England. It's raining.
     
    Roger G likes this.
  16. I've tried a few times getting images of the odd planet with a DSLR and long lens. I really can't recommend enough at trying to get a view of the planets (well, Jupiter and Saturn are the ones that impress) from your back garden or even just getting a look through a telescope. The first time you see them for real is quite something.

    Here's an over exposed RAW shot taken with a D7100 and Sigma 150-600S (1/20th!!, 600mm f6.3 ISO 200). I used 1/20th as that was OK on previous attempts. But this has been my clearest one I've ever taken with a DSLR once the image was dialled back in Light Room.

    Jupiter as taken.JPG

    Then tweaked within an inch of its life in Light Room until I got something recognisable :

    Jupiter RAW tweak.JPG

    Obviously 100% views.

    I think I just supported the camera on a tripod and followed the bright spot buy hand. I have a motorised tracking mount but I don't recall using it for this but I might have done.

    So hopefully this can give you an idea what settings to try and what to expect. Next try Saturn and then the ISS.

    But be warned it could be the slippery slope to astrophotography.

    Jon
     
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  17. I am impressed you could resolve even the surface details using the 600 mm (can we see the great dark spot, possibly not). Thats probably the best one can do from the ground level, given atmospheric diffraction which smears fine details.
     
  18. That is impressive! I could barely see the bands on Jupiter through my telescope and they were in line with the orbits of the moons as your photo shows. I'll go back to my RAW file and see if I can tweak anymore out of it.

    Maybe next time I'll try my 100-400 lens with 1.4x extender instead of the telescope.

    I do not have a motorized mount.
     

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