Astro Photography Tips & Techniques

I am grateful to have had my image of the milky way at Schoodic Point in Maine, included in a Dark Skies juried exhibition in Belfast, Maine. The exhibit is a collaboration between Waterfall Arts, Union of Maine Visual Artists, and Dark Skies Maine with the goal of educating viewers about the ecological role of the night sky and its impact on area wildlife.

I am also honored to have my photograph featured in this short, lovely, New England Living Magazine article about the show. Here’s a link to the article. The show features photography, painting, drawing, ceramics, and mixed media.

Why I wrote this blog post:

However, at the exhibition opening reception, many folks were asking about the technique I used to photograph the night sky. I thought I’d put together a brief explanation on how I got this shot and some other tips about night sky photography.

Introduction:

Being a college professor in addition to leading photo tours and workshops, I seek out opportunities where I can recharge, be taken out of my comfort zone, learn a new technique, and be with other photographers as a student rather than a leader.

Two years ago I signed up for a multi-day astro photography workshop with Maryland based astro photographer, Robert Fawcett. And since Maine has the darkest skies on the eastern seaboard, I didn’t have to travel far. But wow, was I taken out of my comfort zone.

Here’s what I learned and how I made the image:

There is quite a bit of gear preparation and research that must happen first. The most important being that you are interested in the night sky and you have a foundational knowledge about it; constellations, best direction to view the milky way, best time of year, etc.

You will be using a flashlight whenever you are walking around your location, but after that expect to be working in complete darkness. Yes, you could use a flashlight but if you are with other people they will be mad at you for ruining their night vision and for throwing light into their image, even if they are 50 feet away from you.

So just forget about this as an option. If you are alone, which I don’t recommend for women, you could put a red filter over your flashlight. But still, your eyes are going to have to readjust to darkness every time you use it. It will slow you down and become frustrating.

So, with that being said, you need to know your camera like the back of your hand. Start practicing days before your shoot.

Things you need to know how to do in the dark.

choose the necessary buttons and dials on the camera
turn on Live View
where the magnifier button is to zoom your monitor for focusing and checking your image captures
how to change your shutter speed in complete darkness
set and adjust your timer or better yet, how to use a mechanical Shutter Release Cable
the controls of your tripod are larger and easier than your camera, but you still need to practice in darkness

Scout a location:

know the correct compass direction for desired sky area to be photographed
find a scene with an interesting foreground
no moon
no light pollution, including distant villages and roadways
clear sky, no clouds, or very light cloud cover
plan your timing

Scout your location in daylight and knowing your compass directions, start to set up your shot before dark.

Camera gear prep for a DSLR:

turn off all auto focus options (before you set your focus to infinity)
set your lens focus to infinity during the daylight and tape your focus ring in that position or read below for how to set focus on location.
turn off all noise reduction options (high ISO and long exposure)
turn off auto ISO
since you are using a tripod turn off all stabilizers
lower the brightness of your monitor screen
make sure you are shooting raw files
set your mode dial to Manual
set White Balance to Custom K 4600
set color space to Adobe RGB
disable Touch Screen Control
turn off Back Button Focus just in case you fit it by accident in the dark
turn off Flash if you have one
you’ll want a normal to wide focal length to get the entire sky

On location:

if you didn’t set your focus in the gear prep stage you can do it now by using your Live View and zooming in to the brightest star and manually focus on it
set your composition; you likely won’t be able to see your composition until you take a shot and view it on your monitor, then recompose your framing, repeat the process until you have the desired composition.
use an aperture of 2.8 or wider (this does matter)
to determine your shutter speed for a full-frame camera, use the 500 rule; divide 500 by your focal length number and you will achieve the longest shutter speed that you can possibly use before the stars become blurry from the earth’s rotation (not focus blur), 500 ÷ 24mm = 20 seconds

I used a 24mm lens, F 2.8, with an 8” exposure at 6400 ISO. I shot 12 exposures, one immediately after another. Using a cable release is best for this, but if you must use your timer, set it for a 2 second delay.

Brief Explanation of the initial steps of post processing:

Without any development adjustments, I downloaded the 12 images into a stacker software to merge the frames for noise reduction and increased quality. I used Starry Landscape Stacker. Since the earth had moved between my first and last shot, the Stacker also aligns the elements of the image to overlap them perfectly.

Why 12 images and why stack them, you might ask? Noise tends to be random across different exposures. When a set of images are stacked, the important areas of the scene that had been recorded exactly the same 12 times are averaged, while the overall noise from each image is diminished due to its randomness. Please note, noise is not completely eliminated, just reduced.

Once the 12 images are merged, you then have one single image, and you can now make necessary development adjustments in your regular photo software.

Try to enjoy the process and the education that it offers.
I wish you lots of success!

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