Astrophotography And The Winter Solstice

The Winter Solstice occurs annually on December 21, and while this year included unique astral events such as a meteor shower and planetary alignment, the solstice presents a unique photographic opportunity every year. By virtue of early sunsets and cold dry air, it’s the perfect time to practice astrophotography without staying out into the dead of night and with the added benefit of clearer air providing better views of celestial bodies. Here are four ways to find more success with astrophotography practice during these long winter nights.

Keep The Camera Warm

Unlike summer astrophotography adventures, winter’s lower temperatures present additional challenges. First and foremost, cold batteries drain faster. So along with bringing extra batteries, carry spares in an inner pocket to keep them close to the body and thereby warmer. Better still, consider keeping the camera warm too. Long exposures build up heat—which in the extreme can add noise to the digital image—but it’s not likely enough to keep batteries warm and toasty. Some outdoor photographers swear by chemical hand warmers (such as those from Hot Hands) and keeping them in the same pocket as spare batteries. Heat packs can be rubber-banded to a spare or even strapped to the camera’s battery compartment in bitterly cold conditions.

Another issue, especially when working near water or in particularly humid environments, is condensation or frost forming on the lens. Wrapping the lens barrel with a thick sock or even an insulated can cooler might help, but even better is a dew heater. This can be achieved by affixing the same sort of aforementioned hand warmer to the lens barrel before wrapping it with insulation or by purchasing a battery-powered dew heater designed to be strapped to the lens. Either way, this will help the lens stay nice and warm and free of frost for the duration of the shoot.

While you’re at it, don’t forget to keep yourself warm too—particularly with gloves on your hands, thermal socks on your feet and a good hat on your head. If you’re uncomfortable outdoors on a cold night, you’re going to be distracted or hurried—neither of which is a recipe for making great photographs during these long, cold winter nights.

Get Dark

Any time you’re photographing the night sky, step one is choosing an ideal location. Not only is this important if you’d like to include earthly elements such as mountains, lakes or trees within the frame, but also because it affords you the opportunity to avoid light pollution—by getting far away from city lights. Light pollution makes it more difficult to see the stars clearly. At a minimum, choose a location in which nearby manmade lights aren’t visible to the naked eye. In an ideal world, travel many miles from urban areas where darkness prevails. It’s best to plan ahead if possible—to know what to expect from the landscape and the sky you’ll encounter, as well as to safely hike to your location while it’s still light out. If you’re bringing a flashlight—definitely a good idea—channel your photographic forefathers and use a red gel to make a darkroom-style safelight. The red light won’t cause your eyes to readjust, making it easier to maintain your night vision throughout the shoot.

Choose The Right Gear

This process requires at minimum a camera, lens, tripod and a way to trigger the shutter without laying hands on the camera. Starting with the tripod, choose one that’s simple to use and stable above all else. Being able to weight the tripod for added stability is helpful, so choose one with a hook protruding from the bottom of the center column from which you can hang your camera bag or a sandbag. This will help keep any wind from buffeting the setup during a long exposure.

Next is the camera to be affixed to that tripod. A full-frame sensor DSLR is a great choice because of its ability to produce low noise at higher ISO sensitivities. Ideally, you’ll want a DSLR with a mirror lockup feature so that the slapping of the mirror doesn’t vibrate the camera during the exposure. Avoid that with a mirrorless camera that removes this possibility altogether. In either case, you’ll want a camera that can be fired without a manual button push. This could mean using a camera with a pluggable cable release, a wireless shutter release compatible with the camera or, in a pinch, setting a self-timer so that a few seconds pass between pressing the release and the shutter opening. My favorite option (since we’re living in the future, after all) is a camera with a compatible smartphone app that’s capable of releasing the shutter remotely as well as showing a live view of what the sensor sees and the ability to make exposure adjustments to ISO, shutter speed and aperture a snap from the app.

Lastly is the lens selection. Of course, there’s no single lens that’s a must-have, but many astrophotographers prefer the 24mm focal length for its ability to take in a wide-angle view of the night sky with minimal distortion. Prime lenses can be preferable because of their optical quality and because they absolutely eliminate issues such as zoom creep throughout long exposures, but zoom lenses are perfectly usable too. Plus, they’re versatile for zooming in and out to compose with earth-bound elements. Fast lenses make for shorter exposures too, which is very helpful for star-filled landscapes. And while they pale in comparison to telescopes, a super-telephoto 600mm lens can reveal impressive details on the surface of the moon. Just know that such a long lens will eliminate all of the earthly elements from the frame and require even more vigilance when it comes to stabilizing.

Choosing Camera Settings

First, with the camera on a tripod for stars or anything else, never engage image stabilization (or vibration reduction) as this will attempt to stabilize an already static camera and induce artificial movement and blur the image.

Some photographers when photographing a starry sky choose to crank up the ISO and use a faster shutter speed and a wide-open aperture. The issue with this approach can be that the high ISO causes increased noise, which isn’t ideal when looking at a frame full of little bright specks (stars) in the first place. Neither, however, is the approach of stopping down the aperture, using the minimum ISO and allowing a long shutter speed to capture the stars. At a 30-second shutter speed, the stars in the sky will have moved noticeably during the exposure. It’s one thing to make star trails (requiring much longer exposures of minutes or hours) but entirely another to have instead of pinpoint stars little fuzzy oblong shapes.

So, if you’re not doing a 15-minute exposure in an effort to record a star trail, shorten up that shutter speed to a few seconds, 10 to 15 maximum, in an effort to keep the stars sharp. Start by setting the shutter speed and then adjust the ISO and aperture accordingly. A wide-open aperture will help keep the ISO (and therefore the noise) down, but it’s also not the sharpest aperture on a lens. So consider instead shooting a stop or two from wide open. The added sharpness should be evident in the resulting image and you’re not sacrificing a lot of light. Whatever you do, try to avoid cranking up the ISO too high. Ideally, ISO 1200 or slower should work to allow for a fast enough shutter speed and a sharper aperture without too much noise. Striking the right balance between ISO, aperture and shutter speed can be a challenge, but understanding how each impacts the finished image will help you make the right decisions when you’re out there photographing in the middle of a very long night.

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