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photo:astroscapes

astrophotographic landscapes of the Milky Way

plan ahead

  • if your aim is to get the most aesthetic imagery of the Milky Way, you need to not only have a clear sky with no moonlight or light pollution, but you need the Milky Way (in particular, the area around Sagittarius) to be in the part of the sky you will be shooting
  • in the Southern Hemisphere, you will find it best with the Southern Cross at around the 5 o'clock position in the sky (the Southern Cross circles around the South Celestial Pole in the sky each day - for example, just before dawn in the Australian winter when it will be near the south-west horizon and you can place the Southern Cross in the far left of your scene assuming you will be doing a panoramic stitch of the arching Milky Way

  • Sony a7S II full frame mirrorless camera firmware update 2.10 and Sony a7R II full frame mirrorless camera firmware update 3.30 in Aug 2016 has introduced a bug that “eats” stars in RAW and JPG astrophoto images when exposure time is 4 secs or longer, or BULB - these cameras are no longer suitable for astrophotography!
  • Bad spatial filtering isn’t new to Sony’s Alpha cameras. Even with the older firmware, all recent Sony alpha mirrorless cameras including the a6000, a6300, a6500, a7S, a7R, a7, a7II, a7sii, a7rii exhibit the “Star Eater” issue when using the Bulb exposure mode - in these cameras, use timed exposures not BULB!

the hand held option

what you need

  • high quality f/1.4, f/2 or f/2.8 wide angle lens that gives sharp star images across the frame wide open
  • tripod
    • optionally with a panoramic head if doing stitched shots with foreground subjects in the image
  • lens dew heater
    • no point trying to shoot once dew falls on front of the lens!
    • dew forms when lens becomes colder than the dew point
  • exposure trigger
    • if doing exposures longing than 30 secs for the landscape component, you will need either:
      • shutter release mechanism to keep shutter depressed during BULB, or,
      • use an Olympus OMD camera which has Olympus Live Time mode (just press shutter to start and again to end when it looks bright enough - or just use the TIME mode if you don't wish to see the image developing)
        • can also use these cameras in Olympus Live Composite mode to do star trails without blowing out foreground subjects!
        • these cameras also allow Live Boost mode so you can readily see and focus on the stars in the EVF if using wide aperture lenses

40.media.tumblr.com_ed7f301f8949d6808998c0044dd15b42_tumblr_now1xqizky1u7lvvio1_1280.jpg

Nice pano stitch of 10 images at f/2.8, ISO 3200, 15sec, but the Tokina 11-16mm f/2.8 lens is showing awful image quality at the tops of each frame - lens choice is critical!

camera settings

  • manual white balance:
    • for Milky Way generally looks best at 3200-3900K to keep stars looking blue
  • manual exposure for the Milky Way:
    • many aim for an exposure value of -8EV for the Milky Way = 25sec, ISO 3200, f/2 to 2.8
    • shutter speed:
      • to avoid noticeable star trailing, exposure length should be kept below 400/(effective full frame focal length), however, even at this shutter speed, you will get star trails on large prints from high resolution digital sensors so you may prefer to use a shorter exposure by 5-10secs, or, as calculated by this complicated NPF rule formula 7):
    • preferably should look overly bright in camera (neutral or ETTR histogram) without blown highlights
    • to get the whole view of the Milky Way, you will need about 14 vertical images stitched if using a 14mm lens (on a 35mm full frame camera)
  • landscape exposures (moonless sky):
    • 20min, ISO 1600 at f/2.8 (may need a warmer on the lens to prevent dew forming)
    • 5min, ISO 1600 at f/2.8
    • 1-10min, ISO 400-1600 at f/8 with light painting of foreground - may need multiple shots with different focus points
  • RAW mode
  • long exposure NR ON or AUTO

post-processing

  • in Lightroom, remember to:
    • set Sharpening Masking to a high value to avoid sharpening blank areas of the sky
    • add some Clarity to make stars pop (but too much gives a halo artefact)
    • apply some noise reduction
    • may need to remove vignetting if planning to stitch images
  • then in PS:
    • you need to blend in all the images:
      • Milky Way exposures
      • foreground landscape exposures
    • apply further noise reduction (can be done by 3rd party plugins such as Nik Dfine)
photo/astroscapes.txt · Last modified: 2017/12/02 04:50 by gary1