COMMON ASTROPHOTOGRAPHY OBSTACLES & HOW TO SOLVE THEM.
This articles aims to describe the most common obstacles you’re likely to encounter in your nightscape quests, and ways to mitigate them. The goal is to help you maximize your enjoyment by developing strategies ahead of time for coping with the inevitable challenges and potential frustrations that accompany any outdoor activity.
With patience, perseverance, skill, and good luck, you will be rewarded with one or more high-quality images that you will be proud to hang for display or videos you will be excited to share. Although challenging, landscape astrophotography is a rewarding pursuit that you can learn and improve through practice, provided you give yourself enough time.
Logistics—Time, Travel, and Costs.
There are several fundamental logistical challenges to nightscape astrophotography. There can be major time investments involved in planning, traveling, and creating beautiful images. Objects move inexorably across the night sky. The costs of landscape astrophotography equipment and travel can add up. It is important to recognize these time and potential cost logistics so you make appropriate decisions and suitable preparations.
The large number of extraordinary nightscape images that we constantly see on social and commercial media, art exhibitions, television, and film documentaries have spoiled us. They make it easy to underestimate how difficult and time-consuming it is to actually create them. Planning and completing a successful landscape astrophotography session can take far longer than one might think. In many cases, we need to book airline tickets, rental cars, hotel accommodations, spend a day flying, and then driving hundreds of miles to reach our ultimate, unfamiliar destination.
Once there, we need to unpack and prepare for the evening’s events. We need to carry our equipment to the shooting location and set it up during our scouting explorations during the day as well as our shooting expedition at night. Then, provided the weather holds, we will likely spend several more hours collecting images before returning home and spending, yet more hours post-processing them.
Night sky objects move with a seeming relentless consistency. There is no rewind button. Once the moon has crossed the horizon there is no going back. Once the Milky Way has begun to set, that’s it for the evening.
Try measuring the time it takes for the sun to completely disappear beneath the horizon after first touching it. You might be surprised to find it is only a few minutes. The moon takes even less time.
On more nights than I can remember, image possibilities have slipped away as I have dithered, unsure of which image or image sequence I should take next! It really pays to have carefully thought through which images you wish to shoot during a given evening, and in what order, and with which camera and lens combination.
Having even a cursory written plan can be remarkably helpful late at night when you are cold and tired; having the detailed plan we developed can really pay off. It can make the difference between coming home with memory cards full of images or coming home imagining what might have been possible if only there had been more preparations or time available.
By now you realize that I am a firm believer in the value of thoroughly preplanning your trips. In addition to assessing the logistics discussed above, you may wish to estimate how much time you will need to create your image(s)—and then double it. Now you will have a reasonable buffer to deal with all the inconvenient realities of working in the field—airplanes and satellites flying through your shot, headlights from a car ruining a time-lapse sequence, needing to re-focus, changing a dead battery, trying a second composition…the list is endless.
Setting Up at Night.
You may find it helpful to arrive on-site at least an hour before your earliest shooting time. In addition, be sure to allow ample time to park, load up your gear, and hike in to the destination. Even though you have scouted the site, determined the best tripod location and reviewed your images from the day and chosen your favorites, everything takes longer than you might think! Simply setting up the tripod, acquiring focus, fine-tuning the composition, and setting exposures all take time.
The worst feeling in the world is to be late to an event that simply can’t be replayed.
Focusing in the Dark.
Focusing in the dark is probably the biggest technical challenge to those beginning in landscape astrophotography. Since it is done with your camera and/or your lens set to a manual focus setting, it is entirely up to you to achieve the best focus possible. You may spend all of your first night, or two, or even three or more mastering this vital skill.
A sharp focus is critically important; blurry, out-of-focus stars will ruin an otherwise perfect image. It is important to be patient and give yourself time to learn this skill. Practicing at home will save you great frustration when you are in the field.
Many higher-quality lenses have a marking on the barrel that indicates a focus distance of infinity, ∞. While it would seem straightforward to simply set the focus ring to the setting, pinpoint focus of night sky objects is rarely achieved by doing so, most certainly so for zoom lenses. Changes in temperature, for example, can cause dimensional changes in lens components that lead to tiny, yet noticeable, focus imperfections.
Changes in the lens zoom setting can discernibly shift the focus position as well. I prefer to always focus directly on the stars themselves, thus ensuring the sharpest and most reliable focus of the night sky. Since stars are too dim to see clearly through the viewfinder, however, you must rely on the live-view feature of your camera. This process can be extremely challenging to perform in the field. A handheld loupe can assist in viewing the stars on your camera’s liquid-crystal display (LCD).
An alternative is to focus on the distant horizon, instead of the stars, before the end of civil twilight, and simply maintain this focus setting throughout the night. Another approach is to find a distance light on the horizon and to use it as a focusing target, again instead of the stars. Once you have achieved focus, you might like to tape the focus ring in position with gaffer’s tape.
Memory Cards and Batteries.
Multiple spare camera batteries and memory cards should always accompany you into the field. Just like all equipment, both can occasionally malfunction. You will always want to have an extra empty memory card and fully charged battery on hand, just in case. Nothing is worse than being in the middle of an exciting shoot, only to realize that you have exhausted your memory, or drained your battery, and if only you had a spare replacement, the shoot could go on.
They are such small objects, yet they have the potential to enable or completely end an entire night’s shooting. Finally, always check that your camera actually contains its memory card and battery before venturing into the field.
All of us, at one time or another, have driven to our night’s destination, excitedly hiked up the trail to reach our shooting location, pulled out our camera only to realize its battery is still at home, plugged into the battery charger! There are a number of methods for carrying spare memory cards, including wallets, sleeves, and plastic cases.
One important reminder: be careful to never touch the gold-colored metal contacts on camera memory cards with any part of your body. Doing so inadvertently may trigger a discharge of static electricity from your body through the card. This electrical discharge may then interfere with and corrupt the data stored on the card, and ultimately the entire card itself.
Batteries generate electricity via internal chemical reactions. The strength of the reactions depends strongly on the ambient temperature.
If the temperature is too low, then the rate of the chemical reactions slows, significantly reducing the level of electrical output. This reduced output is manifested as a shortened battery life. Solutions to this potential problem all involve keeping your camera batteries as warm as possible.
On many occasions, I have successfully revived seemingly dead batteries simply by warming them in my hands or in a trouser pocket for several minutes. Attaching portable handwarmers to the camera body with tape, rubber bands, or other methods can prolong the battery life in the camera. Handwarmers also help keep the inner mechanisms of the camera working smoothly at sub-zero temperatures.
Other Issues.
There are several camera settings that can pose problems if neglected. Here are just a few examples; it is always a good idea to create a list of these and other potential problems that you actually consult in the field, so as to ensure smooth operation and a successful outing:
Ensure your camera/lens is set to manual focus.
Adjust the zoom setting of your lens before establishing focus.
Be sure to turn off the long-exposure noise reduction setting during the collection of star trail images, otherwise the star trails will be dashed lines, with the gaps corresponding to the periods when the noise reduction was being performed.
When conducting a sequence of images using an internal or external interval timer, it is important that the image collection period be longer than the shutter speed. Be sure to monitor the ISO so that it is not higher than necessary.
Monitor the focus throughout the shoot; it is all too easy to accidentally and unknowingly bump the lens during the night, knocking it out of focus.
Depending on the complexity of your night’s operation, you may end up with a number of electrical cables attached to your camera. It is important not to accidentally snag one and unintentionally shift the camera and tripod.
If you are using a tracking head for the tripod that requires external power cables, take care to ensure they have enough slack to allow for the tracking head’s movement as the night progresses. Be sure each section of the tripod and head is fully secure.
Adjust your camera’s LCD brightness to its minimum level to preserve your night vision and the camera battery life. Turn off your camera’s image review feature to also preserve battery life.
Related questions.
My lenses keep getting misty. What should I do?
Lens dryness and cleanliness are two issues that must be maintained. Under the wrong conditions, dew, and/or frost will condense on everything, including your lens. Unfortunately, other than using handwarmers taped to the lens or a dedicated lens heater, there is little that can be done to prevent dew or frost formation during a shoot. Lens cleanliness, however, is a maintenance issue that is easily kept to satisfactory levels.
What is post processing?
The camera’s ability to sense and record an image mimics, but in no way matches, the actual perceptive qualities of human vision. Fortunately, we are able to digitally alter, or post-process the images recorded by the camera to more accurately reflect what we perceive. Often, more than a single image is required to fully capture the essence of what we are able to see, or to correct an artifact in the image.