Shooting for the Stars: A Perspective on Astrophotography

astrotcard

Are you tired of spending night after night under the stars and having nothing to show for it besides a handful of blurry, uninspiring, and disgusting images?

What do you say? Are you ready to take the night back? Grab your camera! I’ll meet you outside!

 

Welcome to Starlight Boot Camp

 

No matter what kind of camera you’re using—it needs to be a slave to your will. Every parameter needs to be manually adjusted. Automatic settings will not work.

You need to be in control of three critical aspects:

  1. Aperture

  2. Exposure

  3. ISO

Most cameras have the option to adjust at least a few of these settings. Feel free to prospect through the menus and discover what your camera is capable of…well? What are you waiting for?

All camera’s aside: the lens you’re using dictates how long the image exposures need to be (if their unguided).

A wide focal length, such as a 24mm, offers the ability to take longer exposures without stars morphing into all sorts of odd shapes, depending on accuracy of polar alignment and declination of your camera.

 

** Rough Exposure Guide **

24mm Lens = about 30 Seconds

50mm Lens = about 10 Seconds

As the focal length increases, the exposure needs to be shorter, especially if the images are unguided.

Use the two examples above as a general reference for how long the exposures need to be. Anything longer than a 100mm and you’re going to need a guiding system (or take very short exposures)

Alright! Let’s see what happens when we break the rules, shall we?

overexcygnus

Over-exposed Cygnus

Nasty, huh?

The image was taken with a Canon 18-55mm kit lens. The exposure was a little more than 60 seconds. Notice how the stars look like elongated rectangles? Lovely.

overexcygnuscrop

Cygnus (Crop)

It’s easy to see the star trails once the image is cropped. The stars look like shiny rectangles, and that’s what happens when the exposure is not calibrated.

Let’s see what happens when we follow the rules:

Orion7

Orion’s Belt

The photograph looks much better, right? The image was taken with a Canon 50mm macro lens (About 10 seconds exposure). Star trails are minimal, as well as the unsightly sky glow.

Orion

Crop of Orion’s Belt

In the cropped image, trailing is noticeable, but tolerable. If the exposure was a few seconds longer, then the trailing would be unmistakable.

Dipper58

The Big Dipper

The Big Dipper image was taken with a Canon 24mm prime lens (30 seconds exposure).

Dipper58

Crop of Big Dipper Handle

With a wide angle lens, even when the image is cropped, trailing is hardly noticeable.

Secret Stuff You Need To Know

 

I said this a few times before, but I have no problem repeating myself:

A zoom lens is a pain in the ass to use.  I highly encourage everyone to get a prime lens as soon as possible.

Acquiring a critical focus is essential, and it’s much easier to focus a prime lens. Simple as that. Yes. A zoom lens can be used to image stars, however, the process is more convoluted.

Secret Tip #1

Turn Off Image Stabilization

 

Don’t slap the camera’s shutter button, okay? I don’t care how much of a ninja you think you are—pressing down the shutter button sends shivers down the camera’s electronic spine.

Most DSLR cameras have a self-timer. Convenient, right? I know! Use it. Please.

Wait! Watch out for the camera’s mirror, which is flipped up when the shutter button is engaged. Deep inside the menus in your camera, look for a mysterious ‘mirror-lock up’ option. All brands have different names for it…convenient. I know.

Mirror-lock up, as you probably guessed, locks the mirror in place before the image is taken. Pressing the shutter button locks the mirror in place, and then another press of the button will fire off the exposure.

 Use a remote control to operate the camera.

  • Don’t be impatient and immediately blastoff an exposure after the mirror is locked

 

Secret Tip #2

Shoot RAW

 

The darkness of your sky will determine the numerical value of your camera’s ISO (in my opinion).

If you happen to have the luxury of living under truly dark skies—set the ISO to 1600, and then gradually increase the ISO. If you live near a city or town, ideally you’ll want to start with 400-800 ISO. If the sky glow is over saturating your images, dial down the ISO.

Keep an eye on color saturation.

If your camera has a ‘neutral’ setting or ‘faithful’ try using either of those settings. The ‘portrait’ setting increases the saturation too much, making sky glow become more of an issue than it needs to be.

Or utilize the RAW format.

You can adjust the white balance and other parameters later on.

satcygnus

Cygnus Saturated

Try to maintain a healthy balance between: starlight, sky glow and noise.

cool cygnus

Cygnus taken with portrait setting and tungsten white balance

Secret Tip #3

Image Too Warm? Cool It Down With A Tungsten White Balance

 

Get a solid mount or tripod.

None of your efforts will make a damn of a difference if the camera’s foundation is shaky.

If you need a mount or tripod, I recommend getting a German equatorial from Orion or Celestron.

They’re steady enough to use a DSLR, and the mounts come with a 4.8 pound counter weight. Personally, I like to use two 4.8 pound counter weights, but it’s not always necessary.

Camera5

** Extending the legs on a tripod (or mount) decreases stability **

Try to leave the mount as low as possible. Loosen the bolts on the legs so they’re able to grip into the ground.

Remember: If you’re using a lightweight tin altazimuth tripod, no matter how careful you are, it will shake, rattle and roll to the whims of the world.

If your mount or tripod weighs only a few ounces, then it’s too skinny. To put things in perspective, the mount in the above image weighs over 13 lb.

The tripod in the image below this sentence weighs less than a pound.

Camera6

Stay away from chicken legged tripods. Trust me.

Secret Tip #4

Turn Off All Camera Sharpening

 

A DSLR is a versatile option when it comes to imaging the night sky.

Their relatively wide imaging sensors (even crop sensors) are more than capable of recording high quality constellation portraits. The ability to change lenses is also an advantage that can’t be denied.

 

Venusdusk

Venus at Dusk

A DSLR camera is limited by your imagination. These types of cameras can used for a variety of astronomical subjects:

  1. Planets

  2. Moon

  3. Sun (with a proper filter)

  4. Meteor showers

  5. Eclipses

  6. Halos (sundogs)

 

The LCD screen on the back of a DSLR camera gives you the opportunity to review your images after they’re taken. Study the severity of star trails. Delete the crap. Save the gems.

Enter your email address to follow this blog and receive notifications of new posts by email.

Join 1,430 other followers

About FlyTrapMan (193 Articles)
I have no idea what I'm doing.

2 Comments on Shooting for the Stars: A Perspective on Astrophotography

  1. Been trying to get into this type of photography. Difficult in the summer as it is never really dark enough. Great article though

    Like

    • Yeah, I know what you mean. That’s why I like winter in New England. It gets dark around 4:30pm. Try shooting after midnight during the summer. In August the Milky Way will be at it’s zenith after midnight. If you can find a dark location, I’m sure you can acquire some decent images.

      Like

Say something. Come on. You know you want to.

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: