Monday, May 12, 2014

How to take pictures of The Milky Way

Things you'll need:

  • A DSLR camera with a wide-angle lens. I use Nikon D5100 with my lens focal length set to 18 mm, however you can use any focal length between 12 and 24 mm to get good quality pictures.
  • A tripod.
  • Clear skies with minimal light pollution. This is hardest to attain. Cloudy skies will not give you clear shots of the Milky Way, and if you live in a city like I do, you have to get out of town to really see the sky in all it's glory. I normally go 30 kms out of Auckland to get a decent picture. Also, you want to go when the moon's not shining bright in the sky, as this will decrease the visibility of stars.
  • Optional: a remote shutter release. This helps in minimizing camera movement when you're clicking the picture. I use TriggerTrap with my iPhone, but just about any remote shutter release would do.
  • Optional: a DSLR camera with a movable LCD screen. This is so that you can view the LCD screen from any angle, and believe me, when the camera is pointed at the sky, you would really prefer a movable LCD screen.

This is where the D5100 shines.

Once you have the first three things, you can start astrophotography.

Camera settings:


  • Mode: Manual. This is so that you can manually set the rest of the settings.
  • Focus: Manual, set to infinity. Otherwise your camera will have a hard time focusing at stars!
  • ISO: 3200. If there is light pollution then you will have to use a lower ISO, say 1600, to minimize the light pollution, but may not get good quality pictures. Below is an example of a photo I took of the Milky Way at 1600 ISO with daylight white balance in moderate light pollution, near the city.
  • Exposure: 30 seconds. Due to the earth's rotation, the rule is that your exposure time can be up to 600/ focal length. If you shoot at a focal length of 18 mm, that gives you roughly 33 seconds of exposure time. If you set your exposure any higher, you will start to get star trails (which can be a cool effect in itself).
  • Aperture: The larger the aperture, the better. f/4 is larger than f/16. The maximum possible aperture in my camera is f/3.5 so I use that, however if your camera can go to f/2.8 or even higher, do that.
  • White balance: I've tinkered with this a lot and I prefer Incandescent, or Tungsten. Below is an example of different white balance settings. All three photos are shot at ISO 6400, 8 second exposures, without any post-processing.
Daylight

Incandescent

Fluorescent

  • File format: RAW will give you better post-processing results, but will require special software to edit. I use RAW + JPEG and edit the RAW images in Adobe Photoshop Lightroom.

If your camera supports noise reduction then switch it on.

Sky-guiding apps:


You can use mobile apps such as Star Walk to find out where the Milky Way, or any particular star or constellation, will be on a certain date and time.

Taking the first few shots:


The sky is dark. However your camera is a lot more powerful than the human eye. Hence the objective of the first few shots, is to get a good idea of where the stars are at, and the angle in which you can get a good picture. The quality of the first few shots is not important.

Set the ISO as high as you can, and the exposure to 1 second. Keep adjusting the camera till the Milky Way is in focus. If you can't see any thing in the image that comes up, don't worry. If the image is really dark, double the exposure. If it is really bright, decrease the ISO by half. By the time you reach a 10 second exposure and ISO 6400, you should have a fairly good idea of where all the stars are, and in which angle to position your camera.

A high ISO means you will have more noise, and a high exposure means you will have to wait longer in between shots. This is why were are not worried about the quality of pictures here, just the content.

Taking good quality shots:


You want to end up at ISO 3200 with 30 second exposures.

By the time I took the below pictures I had my camera in a good position so that the galactic center was centered in the frame.

A 10 second exposure at ISO 6400: decent but dark results.

A 30 second exposure at ISO 6400: decent but too much noise.

A 30 second exposure at ISO 3200: This can be processed well.


The final two images I chose were these, both shot at 30 sec / ISO 3200:

This one because Scorpius can be seen

And this one because of the shooting star and the tree

Post-processing


The RAW images taken need to be edited so that the Milky Way stands out. I use Lightroom for editing. The exact settings will depend on the actual picture, however I use this as a rough guideline:

  • Lens corrections: Enable profile corrections
  • Temp: Enough so that the sky is blue and the Milky Way stands out, somewhere between 3000-3800.
  • Tint: Slightly less magenta, slightly more green.
  • Exposure: I tend to leave this mostly untouched, however increasing the exposure can sometimes help.
  • Contrast: + 100.
  • Highlights: + 40 to + 100. This brings out the bright center of the Milky Way.
  • Shadows: + 50 to + 100. This makes the edges and corners slightly brighter.
  • Whites: + 20 to + 40. This makes the starts appear brighter.
  • Blacks: -50 to -100. This helps in increasing the contrast.
  • Lights: + 40 to + 60
  • Darks: + 10 to + 30
  • Shadows: - 20 to -60
  • Noise reduction Luminance:  50
  • Noise reduction Detail: 50
This is my post-processing result for the above two images:



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7 comments:

David Cross said...

The temp of the Milky Way is 4840°K, which comes out a little orange. Around 4000Kcustom WB works well.

IEatCornBread said...

Nice tutorial! I will try out some of those things.

Anonymous said...

thanks.
@ David Cross aren't you bald? lol
j/k in reference to the comedian.

Marzia Khanom said...

Duddeee this is awesome! ..I have the same camera didn't think I'd be able to get the milkyway so clearly will defo be giving it a try .
Thanks ☺👍

Arsh said...

Not sure if my last comment went through or not – anyway lets try again!

Handy tutorial, only thing I’d like to point out is that the f stop is a function of the lens, not the camera. You can get the Sigma 10-20mm f2.8 and that will go down to f/2.8 with your current camera. I recently bought the Canon 10mm-18mm and kinda regret not going for Sigma because my Canon lens only goes down to f/4, which doesn’t work for this type of photography. Cheers.

sandeep khatri said...

Really awesome ... Ur step by step photography tools explanation is awesome ... U r the best .., thanks

Corey Moss said...

Thank you for sharing. I have this camera. I'll try to do something similar. But I still want to edit these images here https://macphun.com/noiseless to remove the noise in the image as much as possible.

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