Astrophotography: How To Photograph Stars With Cheap Gear

If you’re mentally fortified with specialized knowledge, then photographing stars can be as easy as celestial pie—even if you only have access to cheap lenses or cameras. Don’t sacrifice your piggy bank to the astronomical gods! Your porcelain swine shall live to oink another day.

It should be obvious that you need a camera and lens to photograph stars, right? Exactly. The camera should ideally allow the photographer to manually adjust the exposure parameters.

Nope.

You’re not gonna aim a camera at the night sky, blastoff an exposure, and expect the automatic settings to do all the work. Because it won’t happen. Sorry.

The quality of the image is in your capable hands. If the photograph turns out to be an eyesore, then you’ll have to come to terms with every mistake which caused the quality to suffer. Lucky you.

** Unguided Crop Sensor Night Sky Exposure Guide **

• 12-24mm lens =  about 30 seconds

• 50mm lens = about 10 seconds
  

• 100mm lens = about 5 seconds

Do you notice a pattern? Long focal length lenses require much shorter exposure times, or else star trails will become an apparent problem.

Camera sensor size also needs to be considered. A Canon Rebel XSi crop factor equals 1.6x, which means images seem more “magnified” compared to a full frame DSLR camera. A full frame DSLR would need to use a longer lens to achieve the same results as a crop sensor camera.

Nikon, for example, utilizes a 1.5x crop factor.

So…

…what does all of this technical crap actually mean? A simple mathematical equation tells the full story.

50 x 1.6 = 80

A 50mm lens attached to a Canon crop sensor camera is equivalent to an 80mm lens. The crop factor influences how long an unguided exposure should be. Star trails are more apparent with long focal length lenses, remember?

The longer the focal length, the shorter unguided exposures need to be. If the focal length is above 150-300mm, then you’re going to need to manually guide or use a motor drive. Where the camera is pointed in the sky also matters. For example, if the camera is pointed toward Polaris (North Star), then it’s possible to expose for a few more unguided seconds.

** More Useful Tips **

• Engage mirror lock up / or self-timer

• Switch to tungsten white balance (if light pollution is a problem)
  

• Turn off all camera sharpening!

• Use RAW imaging format
  

• Take time focusing (especially if you’re using a zoom lens)

• Lower tripod / mount as far to ground as possible

• Find a dark location
  

A chicken legged tripod might be stable enough to blastoff some exposures, but don’t hold any illusions! It’s far from the ideal set-up. Any tripod will work, though. Unstable tripods or mounts are susceptible to wind, and that means minor vibrations can potentially ruin a long exposure. Cheap tripods can still be used for relatively quick exposures.

A proper astronomical mount is more stable than a malnourished tripod. Orion Telescopes & Binoculars used to sell the EQ-2 German equatorial mount for $199.99, but that particular mount is now discontinued.

Let’s take a look at some single frame exposures, which is what you can expect to see if you’re using similar gear or imaging under a minor light polluted night sky.

The Seven Sisters (or Pleiades) is located in the Taurus constellation. This famous open cluster is visible without optical aide, which also means this particular astronomical object can be easily photographed with inexpensive lenses. All images in this article were minimally processed.

Star trails are not too sever. The slight blue tint in the sky was caused by the camera’s tungsten white balance setting.  A tungsten white balance is able to negate the orange glow caused by street lamps.

Let’s take a quick gander at a cropped image.

Trailing is noticeable toward the far corners of the frame, but it’s not too bad. Image quality naturally degrades toward the corners of the image frame, but this is mainly caused by the physical characteristics of a spherical glass, which is why many telescopes require a field flattener. Field curvature distorts stars into a variety of weird shapes.

Orion is a prominent wintry constellation in the northern hemisphere, and it’s an ideal constellation to practice imaging, because it’s bright and…prominent.

The same camera and lens was used to photograph Orion: Canon Rebel XSi and Canon EF 50mm macro lens. Photographic exposures lasted about 10sec. (unguided).

The pinkish/reddish space cloud is Orion’s Nebula—a famous celestial nursery and home to the Trapezium Cluster. Four behemoth stars are carving the nebula with ultraviolet radiation, so photograph it while you still have time!

Most camera lens cause stars to have a purplish/blueish halo. Optical defects (or astigmatism) will vary. Colorful halos are more apparent around bright objects. Halos are clearly visible around the stars within Orion’s Belt.

Fancy or expensive gear will not make you more creative. Experience can potentially allow you to cultivate creativity, though. If you want to develop your own style of photographic expression, then don’t wait until you have access to the “best gear”. Use what you have, and then apply your gained experience later on.

The Cost of it All

Here’s a list of the gear used in this article, and the average price.

• Canon Rebel XSi: $649.99 (with kit lens). It’s possible to get a new camera body for cheaper.
  
• Orion EQ-2 Equatorial mount—Discontinued
  
• Canon EF 24mm prime f/2.8 IS USM—$550.00
• Canon EF 50mm Compact Macro f/2.5—$359.99
• Chick-legged tripod—Free (if you’re lucky)
  

The gear on the list may seem expensive at first glance, but the price is relatively inexpensive, especially compared to other items. The Canon Rebel XSi is considered an entry-level DSLR, and it’s MUCH cheaper compared to other DSLR cameras. The Orion EQ-2 is currently discontinued.

More affordable options are available.

Canon’s EF 50mm f/1.8 lens costs about $100.00, and the 18-55mm kit lens costs about $199.00. You can find a tripod anywhere—perhaps even in the trash if you’re brave enough to look! You’ll have plenty of cash left over to waste on something else. Lucky you.

You’re now mentally armed with knowledge warheads, and will be able to blow up any problem that enters the battlefield. If you have further inquiries, then contact: matt@prettydamngraphick

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