Adventures in Astrophotography

Hello Cutie Camera Followers!

Dayton here – Hilary’s dashing camera-friendly brother. Hilary asked that I reach out to the blogging world and write about a recent camera-related passion of mine – astrophotograhy! If you’re like me, taking pictures of mountains, sunsets, and rivers can get a bit drab after awhile – so why not point your camera at the sky and take amazing pictures of the stars, moon, or planets? This entry will provide an introduction to those of you who may be interested in basic astrophotography, but have not yet taken the leap.

Cassiopea 1Cassiopeia Constellation – Canon 50mm lens, 10 second exposure, f/2.0, 800 ISO

Equipment and Basics

First off, some requirements – you’ll need a decent DSLR camera capable of modifying your exposure times, ISO, and white balance (I use a Canon Rebel T4i). A tripod is also a necessity – you can use a cheap portable one, but I recommend a large, sturdy one such as the Dolica Proline. At the basic level, this is all you need to create some pretty amazing shots of the night sky. Lenses with larger apertures are also exceedingly helpful, but even stock lenses are capable of some excellent photos. For the price-conscious individual, I recommend the Canon 50mm (~$100, f/1.8) as a general use lens, or the Rokinon 14mm for wide angle purposes (~$350, f/2.8).

Before you walk outside and start blindly snapping photos, let’s chat about the basic science of astrophotography. When you look up at the night sky in the city, there is usually so much light pollution that you’re only seeing the really bright stars, which are just a small fraction of the stars that are really there. When you move out to more rural areas with much less light pollution, particularly those at higher altitudes, thousands of stars that were previously hidden to you are now fully visible. The magic of a DLSR camera is the ability to take long exposure shots, which bring in a lot more light over time and exposes those dim stars that were previously unnoticeable. As with all long exposure shots, you’ll need to make sure the camera is steady and unmoved, hence the need for a tripod. Another great feature of DSLR cameras is the ability to adjust the sensitivity of the camera sensor to light, otherwise known as ISO. By increasing ISO, you can increase the amount of perceptible light (though this comes at a cost of increased noise). Now that we have level-set, let’s go take some pictures!

First Star Shots

Okay, let’s start off by just taking a nice view of the night sky. When you have a clear night (i.e., no clouds) and perceptible stars, take your camera out and aim it to a portion of the night sky. At this point, avoid the Moon as it’s too bright to take long exposure shots. I personally enjoy shots of constellations, such as Orion, Cassiopeia, and Ursa Major (the “Big Dipper”). Once your camera is pointing in the direction of the constellation on a stable tripod (VERY important), set your camera to manual and select the following settings:

  • Autofocus OFF (located on the lens itself)
  • Flash OFF
  • ISO 400 – 800
  • Shutter speed 8 seconds
  • Shutter delay of 2 seconds
  • If you are in the city with heavy light pollution, select the white balance to “tungston”, which will offset a bit of the light from cars and streetlights.
  • Select an f/stop about one or two settings above the lowest possible on your lens.

With the autofocus OFF, you’ll need to focus the lens manually. If your lens can be set to infinity, then that works great, but if not, you’ll need to learn to focus manually. The method I found most useful is to utilize the LiveView mode of the camera (on Rebel t4i and higher), and then use the digital zoom (x5 or x10) to focus in on a bright star. Then, simply adjust the manual focus on the lens until the star is a small, focused pinprick of light. Now, push the shutter release button and viola! Stars! With any luck, you’ll get a pic like the one below.

Orion 1Orion Constellation – Canon 50mm lens, 8 second exposure, f/2.0, 400 ISO

Improving Star Shots

So, you may be looking at your first photos and thinking, “Shucks – this sure is neat! But how can I make this even cooler?” My recommendation is to play with your camera settings and experiment with lots of different shots. A few things you can try:

  • Lowering your f/stop will increases your aperture, allowing more light into the camera. This is typically a good thing for astrophotography, so I recommending trying to go one stop above the lowest setting possible on your lens.
  • Increasing your ISO will increase the sensitivity to light, which is a great thing when you are not in an area with heavy light pollution (though it will increase the noise). If you’re in the city, I recommend keeping it around 400 or 800, as the photo is usually whitewashed at higher ISO’s.
  • Increasing your exposure times will bring a lot more light into the shot. The only issue with this is that the earth is actually moving in relation to the stars, so any exposure longer than about 15 seconds will begin to show star trails, which is the movement of the stars while the earth moves. If you have a wide angle lens, you can do longer exposure shots. Similarly, telephoto lens will show star trails with very short exposure (1-2 seconds). If you want really long exposure shots, you’ll need to get a motorized mount or telescope which will rotate in accordance with earth’s rotation (note: no good options for this are cheap, but will expand on this in future posts).
  • Get out of the city and avoid all the light pollution. Ideally, try to get to high elevation areas, where precipitation is low. This allows for a clear sky that can reveal some amazing stars and, if you’re lucky, views of the Milky Way galaxy.
Big DipperUrsa Major Constellation – Canon 50mm lens, 10 second exposure, f/2.0, 400 ISO

Okay, that’s all for this first entry. Go out and grab some interesting shots – you’ll be amazed at what you can come up with! In future posts, I’ll expand more on taking shots of the Moon and also some discussion on post-processing techniques that can really make your photos shine.

Hilary here! Here is a big THANK YOU to my older brother, Dayton for sharing his new love; astrophotography. I hope to soon go out with him and take some awesome photos too!

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