A Quick Beginner's Guide to Astrophotography

If you're interested in trying out astrophotography, it's a fun, but very different genre to get into. This helpful video will give you some quick tips to ensure you get it right and get those entrancing shots of the stars.

Coming to you from Mango Street, this quick tutorial will get you up and running if you've never pointed your camera toward the night sky before. As mentioned, it's normally best to use a wide angle lens. Try to make it a prime so you can get a wider maximum aperture; in fact, Rokinon's lenses are absolutely fabulous for astrophotography, and you can get them quite cheaply since they don't have autofocus (which you won't need anyway). Here are two additional tips:

  • When using the 500 rule, you need to use your lens' effective focal length if your camera has a crop sensor. 
  • Get away from cities, even towns. Use this tool to find locations near you with the lowest light pollution. Only then will you start to see the glorious range of objects in the night sky.

Astrophotography is definitely its own beast, but even knowing the basics can provide you a useful skill that you can implement into the genres you normally shoot. So, get out there and have some fun!

Alex Cooke's picture

Alex Cooke is a Cleveland-based portrait, events, and landscape photographer. He holds an M.S. in Applied Mathematics and a doctorate in Music Composition. He is also an avid equestrian.

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3 Comments

* Do I really need wide lens for Astro Photography?

Advantages of wide lenses. First, compositional purposes it is nice to include the vastness of the night sky in your photos and having a wide angle lens, of course, helps here. But, there’s a secondary benefit to a wide lens that is unique to photographing the Milky Way and stars. In normal photography, if we want a brighter image we can easily increase the exposure time to say for 15 seconds to 30 seconds, and the bridge or building might now look better. However, when dealing with stars, we have to factor in the earth’s rotational path - which we do not need to deal with in regular landscape photography since the bridge and tripod are both “grounded” to the same planet - everything moves together. However, with the stars, we are moving, and the stars are not. Simply if your exposure time is too long your stars will streak - so instead of nice pretty pointed lights - you get blurred little dashes. Fortunately, there is rather straight forward way to determine your maximum exposure time you divide your lens size by 500 - on a full frame camera or 340 on a Nikon Cropped sensor or 240 with a Canon copped sensor 320 to find your approximate exposure times.

For example, if your lens is 50mm om a full sensor than the maximum streak less image would be 10 seconds ( 50/500 = 10) or (340/50 = 6.8 Nikon Cropped)

But if you had a 14mm - you could expose for about 35 seconds - 14/500 = 35.71 ish. The bottom line - wider lenses equal big bright star photos. However use theses numbers as a guideline only. Check your images for the dreaded star streak aka the coma effect.

Full Frame Rule = 500
Nikon Cropped Rule = 340
Canon Cropped Rule = 320

** Do you really need a f/2.8 lens to photography the stars and the Milky Way?

Since keeping the shutter open for too long will distort your star photographs (500 Rule, see above), you to need to find other ways to add more light to your photos. You can do this by shooting wide open using the lowest aperture number on your lenses, allowing in the maximum amount of light. A lens set to f/2.8 will let in more light than one set to f/4.0 (in fact, twice the light).

That’s not to say that you cannot shoot the stars with a f/4.0 lens, just that your images will look better with a “faster" lens. Don’t necessarily rent/buy a faster lens just for your first nights of star photography; you’re free to learn with your current equipment and consider upgrading later if you discover a passion for photographing the stars. Now you might ask yourself, “don't lower aperture numbers have smaller Depths of Field (DOF)?” They absolutely do! However, when shooting at great distances, the smaller DOF is not an issue: the entire sky will be in focus - helpfully.

My current go-to lens is the Rokinon 24mm f/1.4 ED AS UMC. I chose this over the Rokinon 14mm f/2.8 for three reasons: the 24mm f/1.4 is two stops wider (4 times brighter); secondly, I like to take panoramics of the night sky, often seven panels, and the 14mm creates too much distortion for my taste; thirdly, the 24mm lens (the Rokinon 14mm is good here too) has almost zero comatic aberrations, a highly undesirable lens distortion that adds a tail-like effect (coma) to stars.

Hey Alex, nice and helpful article, anyhow, this is not astrophotography but astro landscape. Astrophotography requires telescopes and guided mounts so that you can shoot deep space objects like Nebulae and Galaxies. I ofter fall for the mistake of considering a nice night landscape, with the milky way on the background as Astrophotography, but after meeting some really hardcore astrophotographers, my mindset changed quite a bit.
I know a few folks, like i've stated, that spent thousands on tripods, telescopes, adapters, filters for certain light bandwidths, removing filters from sensors (dSLRs), CCD sensors specialized for this. Their main focus is shooting the faintest of the objects, with massive stacks of exposures for the best results. Also, expensive software developed for this kind of thing.
Still, astro lanscaping can be really great, i have some pictures myself and there's nothing better than a warm summer night, filled with stars and no light polution :)

Also, lightpollution.info can be of a great help, some astronomy classes, basic ones like knowing some constelations, specially zodiac ones, to know how to place yourself on the field. Also, knowing how to set an equatorial mount, or piggymount a camera on a guided telescope :)

Hey Alex, enjoy the topic, but I have a slight twist.
Photographing fireflies.
They have a really short lit period, but are possibly a bit brighter than a star, and against a dark tree lined backdrop, you have a relatively dense background.
Do you think your way of doing things might work? I just love the fireflies in my neighborhood and they are only a couple of months out of the year event that I'd like to photograph.
Thanks
d