Astrophotography

Taking pictures of the sky!

See Cafuego’s page on software for osx.

I use the following software:

  • AstroDSLR1 for capturing from my DSLR.
  • Nebulosity for stacking images.

Finding a site

Find a local dark sky site. In LA, I like Joshua Tree National Park. However, being able to easily access far-away dark sky sites is one of my primary reasons for learning to fly.

Equipment

You can get away at a bare minimum with just a camera and a tripod. My equipment checklist is:

  • Camera
  • 50 mm lens, because wide field shots are fun.
  • Telescope
    • Telescope camera mount
      • (barlow lens, T-ring, etc.)
    • Bahtinov mask.
  • Equatorial Mount
    • Motors for said mount
    • Batteries for the motors
  • Computer (Strictly speaking, this isn’t necessary - my camera can be set to take a series of photos at once)
    • USB-A to Mini-USB-A (to talk to camera).
  • RED flashlight - white will ruin your night sight. You also want low-lumen, for the same reason.
  • Water
  • Coffee
  • Snacks
  • Camping chair
  • Sleeping pad/bag (even if you plan to stay up all night, bring these).
  • Pillow
  • Paper and Pen.
  • A book or something else to do while the computer does all the work.

Be sure to set the computer to “night shift” mode2 before it’s dark, as red as possible.

Go there, set up camp. Preferably be set up before dark.

Actually Taking Photos

Regardless of how you use it, be sure to write down what you’re taking a photo of when you do it. Even if you know what the constellation/body you’re photographing is anyway.

Also, for stacking3 reasons, the more photos you take, the better it is, but it does have diminishing returns4.

Using a computer

Use AstroDSLR from computer to control the camera. Keep the camera in bulb mode to allow the software to control exposure time.

Make a different folder for each different set of photos you take.

Without a computer

Put the camera in manual mode, and have it set to average.

PostProcessing

Nebulosity doesn’t read the color information from your raw files. Convert them to jpeg, because that’s still better than grayscale images.

for i in *.cr2; do sips -s format jpeg "$i" --out "${i%.*}.jpg"; done

From Nebulosity, open batch -> align and combine images. Select “Translation + Rotation + Scale”, click “OK”, and select the images to stack. Now, select the same star in each photograph as it prompts you. You’re going to go through the sets 3 times (so that it can correct for transation/rotation/scale). Now, do some manual editing, and save the end result.

Post to instagram5 or whatever. Use it as your new desktop background.

1

They don’t have an up to date ssl cert. Site is at www.cloudmakers.eu/astrodslr/

2

or use f.lux to remove as much blue from your screen as possible.

4

It’s essentially an inverse square relation - to get 5x better quality, you need to take 25x more images.

5

flume seems to be a decent OSX client for instagramp. The pro version is worth it.