Shooting the Milky Way

I have a down day for my health today... and I know tomorrow will be the same... so, I'm here at my desk trying to find some simple things to keep my mind occupied with something other than my health.  

There has been a lot of talk in a few of my astronomy groups about trying to capture a decent photo of the Milky Way and it seems that a lot of beginners have big problems with this. Fortunately, it really is not as difficult as people make it out to be. 

Most of these beginners have brand new dSLR's which are more than capable of capturing the Milky Way yet they are having difficulty capturing a decent image so I figured I should write something with some basic info about how to accomplish this type of photography. Any dSLR, technically speaking, is capable of capturing a pretty good image of the night sky so the biggest obstacle is learning how to use your dSLR. Today's mirrorless cameras are just as adept at this type of photography and some mirrorless cameras far exceed many dSLR's.

Let's first talk about this image here in the blog, above. 

I shot this image almost ten years ago with a camera from 2008. Even more surprising is the fact that this camera only has a tiny 2/3 inch sensor which is 15x smaller than the sensors I use today. This old camera served me well for a number of years but it is really only a point-and-shoot camera with an absolutely tiny sensor. As long as your camera has manual control over choosing settings, then you can shoot images of the night sky. 

This camera that I used for this image has only a fraction of the capabilities of today's mirrorless and dSLR cameras yet my image is pretty good. That being said, the better and the newer the camera, the better your image quality will be. (I really need to get out there to shoot more Milky Way photos with my newer cameras!)

Here are the basics:

1. Know where to point your camera. Stellarium is a free astronomy program that will show your night sky right on your computer, tablet or cellphone. Use this program/app to figure out where and when to find the Milky Way in your sky. Stellarium will show you the direction to point as well as the altitude in degrees. You can even use camera, lens and telescope simulations within the program to actually see what you'll see with your particular camera and lens (after you input the appropriate specifications of your particular gear, of course).

2. Use a tripod. You'll need to keep your camera perfectly still during these long exposures so you must have the camera mounted on a sturdy tripod. You must not touch the camera during the exposure. You must also keep everyone around the tripod perfectly still to avoid vibrations from the ground (or, worse yet, vibrations through the deck if you are on a deck) traveling up into the tripod. Also, if it is windy out, the wind can ruin a long exposure shot by slightly vibrating/moving the camera on a lightweight tripod. 

3. Use a remote shutter release or the camera's self-timer. You'll need the camera to be perfectly still so you should not be touching the camera during the exposure. You need to use a remote or the self-timer so the camera can remain perfectly still through the exposure.

4. Set your camera to all manual mode. You'll need complete control over the camera's settings so you need to be able to set your camera to "M" mode as well as manual focus.

5. Understand exposure. You really need to understand the basics of exposure using ISO, shutter speed and aperture. This is referred to as the exposure triangle. The best way to get a grasp of exposure is to just experiment with each of these settings. Change one setting at a time and look at the result on your LCD screen. Practice in a well lit room on a relatively close object. The differences will be far easier to see under these conditions.

6. Learn to focus manually. Auto-focus will not work in complete darkness and especially not on stars. You'll need to learn how to manually focus your camera to make the stars in your view finely focused pinpoints. Today's cameras have a lot of useful tools to help with this but each camera is different so you need to do some research on your own camera model... in other words, read your camera's manual.  (This was always my grandfather's first response whenever I had a problem with something... Did you read the manual?)  Some cameras can magnify your view to help you focus... or you can have a tool called focus-peaking... or, you can simply focus on something bright that is already at infinity (ie, a utility pole in the distance, a tree in the distance). Regardless of which focusing aid you have available on your particular camera, you'll need to know how to manually focus your camera.

7. Set your white balance to "daylight". People have slightly differing opinions on what might be the perfect white balance but "daylight" is a pretty middle-of-the-road white balance for this type of shooting.

8. Use the widest, fastest lens you can afford.  "Fast" means a lower aperture f number. Ideally, a lens around f2.8 is great. A lens at f1.8 would be better as long as it is sharp with little to no coma. A "wide" lens is in the range of 18-28mm (equivalent 35mm field of view). An ultra-wide lens such as the Rokinon/Samyang 14mm f2.8 lens is a great place to start because it is sharp, it is fast and it is inexpensive. 

9. Open your aperture as far as possible. This means adjust your aperture to the lowest number. The lowest f number will open the opening of the lens (the aperture) as much as physically possible and allow the most light into the camera's sensor. 

10. Set your ISO to 1600 to start. You can possibly change this setting to ISO 800 if you are seeing too much noise in your images. ISO 1600 is a better place to start though. If you have a newer model camera, you could probably even start at ISO 3200.  

11. Set your shutter speed to the appropriate speed.  What is appropriate here depends upon the focal length of the lens. If this is a foreign concept to you, then use an exposure calculator. (Click the link.) This particular exposure calculator will give you settings for your shutter speed, ISO and aperture. If your shutter speed is too long for your particular lens, then you will get some star trailing due to the Earth constantly rotating on its axis. If the shutter speed is too short, you won't capture as much light as you could have with a longer shutter speed. 

12. Shoot your exposure using a remote shutter release or the self-timer.  

At this point, you can check your shot on your LCD screen and then adjust your exposure as necessary. There are many ways to improve images in post-processing as well, within reason of course. I'm not going to get into post-processing here because one could write a book on that topic alone and it takes years of learning and practice to master post-processing. The best and easiest thing to do right from the start is get the basics I mention above done right.

The example photo, above, is a good example of how easy this photography can be since I used a ten year old point-and-shoot camera with a small sensor and yet I still managed to capture a halfway decent image. It is not a "great image" by any stretch of the imagination but I don't think anyone would argue that it isn't a halfway decent image. 

I really do need to get out there some night with my newer, better photography gear to capture some better shots!