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Big Bend '17: No. 17 - SuperMoon Rising

Updated: Apr 23, 2020

As the luminous SuperMoon crested the long, gradual curve of the mountain range along the Eastern horizon of Big Bend National Park, beams of warm, reflected sunlight lit up a thin layer of moisture still clinging to the desert floor. The band of light split the earth and sky with the ghostly afterglow of a pale and distant sunrise. The stars still hung in the deep blue canopy of night, but the moon was undeterred as it moved ever higher to overtake their tenuous domain.

The sun was still setting in the West as the Super-moonrise began, and I was caught off guard by how early it came into view; it was considerably sooner than my research had said it would be. I had planned the evening using a general location near Big Bend in order to get the times from the database in my Photopills app because my exact location was not available. I had expected a difference of a few minutes based on my location within the chosen region, but this was over 10 minutes early. Needless to say, the alarms I set to get my camera ready went off about the time the moon was rising so I scrambled to carefully rotate the tripod on the bear box and get the telephoto lens set up.

The Nikon 300mm f2.8 VRII is an incredible lens, but it is also incredibly heavy and bulky in contrast to my comparatively diminutive 28-300mm zoom lens. The addition of Nikon's 2x (TC-20E III) or 1.4x (TC-14E II) teleconverters only increase the distance between the tripod leg and the heavy D750 dangling off the back end. I can anchor it directly to a ball head, but then it is very difficult to move around, and it tends to drift unpredictably (move up or down depending on orientation) after I tighten things up and let go of the camera end of the rig.

In order to make the setup more manageable, I haul around a Wimberley Sidekick to better support the load, but it takes more time to setup as I need to balance the equipment in order for it to properly act as a gimbal. A key part of the setup is getting the lens foot rotated 90 degrees and clamped down at just the right distance to balance the massive glass element on the front of the lens, with the camera on the back. When I purchased the lens second-hand around a year prior, I didn't like how tenuous it felt to attach an arca-swiss plate to the bottom of the small factory plate, so I replaced the foot entirely with a Really Right Stuff LCF-14 that already has an arca-swiss plate integral to the entire foot (meaning I can shift the position of the clamp as required as the weight of the setup changes). This makes the base of the lens very stable as it is attached directly into the lens ring via 4 screws (which I coated in Loctite to resist backing out). I highly recommend the LCF-14 to anyone using this lens.

A Quick Comment on Lunar Nomenclature - You may have noticed by now that I continue to call this event a "Supermoon" even though I know full well that the correct term is a "Full Moon at Perigee Syzygy." I don't support the astrological musings of Richard Nolle, and I still think that people should know the correct term and what it means, but the term "Supermoon" is just easier to say and I think that's the main reason why it remains so engrained in American parlance. And let's be honest, there is something super about a moon that is 14% larger and 30% brighter. The difference is obvious to even the untrained eye, and it's fantastic for a photographer. Regardless of which term you use, just get out and experience it!

We noticed the moon just as it crested the horizon, but by the time I had things setup and ready to go, the moon was already the majority of the way above the mountainous horizon. The amount of moist air between my camera and the moon is always greatest when I aim at the horizon, so the moon was blurry, distorted, and the colors shifted abnormally. Horizontal waves of heat still radiating off the desert seemed to compress the moon into a wavy, oblate sphere. I started with the 1.4x teleconverter so I would only lose one stop of light, but the lighting conditions were still a challenge.

In order to try and get more detail of both the moon and the landscape, I started taking a few bracketed photos which were considerably more difficult to post-process into an HDR image (High Dynamic Range) than I had hoped. First of all, the atmospheric distortion was prominent at this angle, so reduced sharpness was inevitable. Second, in order to maximize the size of the moon in relation to the sensor size (thus maximizing detail), I was shooting at 600mm using the 300mm f2.8 with a 2x teleconverter. The 2x drops the exposure by two stops (1/2 the light per stop, so 1/4 of the light overall) which made my f2.8 effectively an f5.6. This drop in light required higher a ISO value (sensor sensitivity which leads to more noise) and slower shutter speeds (which can lead to motion blur, especially at long focal lengths). Lastly, at 600mm the the moon rapidly traverses the frame during the exposure times of the bracketed shots, which means the moon shifts considerably from the -1EV shot to the +1EV shot. This makes it so that auto-alignment in post-processing never seems to work (which leads to me doing it all manually).

In order to get a clear shot, I need to let the camera settle after I moved it to the moon's new position (which changed every sequence of bracketed shots), and then between shutter releases when vibration from the mirror slapping up and down can cause blurring. I would love it if Nikon would create a Mirror Up mode for bracketed shots so the mirror stays up for an entire sequence, but unfortunately they don't have that option yet. I'm planning to send a request for a future firmware release, but Nikon is not known for taking suggestions quickly. Needless to say, even when I shot each image as quickly as possible (without disrupting image sharpness), it took a considerable amount of manual finessing to get the images to merge correctly.

With a single image, only a hint of the mountain below the moon can be seen.

While the moon was just above the ridge, it maintained a slightly warm glow while the sky and landscape kept the cool blue of night. However, once the moon reached higher in the sky, the reflected light of the sun began to bounce off the moisture still hanging low on the desert floor, and the temperature of the light transitioned to a warm halo that resembled a sunset on a hazy day. It was a bit disorienting for the moonrise to be so bright considering we had just witnessed the sun setting on the opposite horizon. It almost felt as if we were stranded on a planet that had a pair of suns, one larger and one smaller, that rose and set opposite of each other.

At the top of the image, just to the left of the moon, you can see a single star that managed to be bright enough to still show up in this image.

I dropped the 2x teleconverter so I could get more detail from the foreground and gain back the two stops of light I lost. This allowed me to drop the ISO and reduce the overall noise in the image. Shooting at 300mm also had the benefit of reducing the required shutter speed as the moon no longer traversed the sensor as quickly.

I found it interesting that the images of the moonrise began to look very similar to a sunrise as the moon rose further over the mountains. However, while it was still sunlight bouncing off the reflective surface of the moon, substantially fewer photons bounced off the moon than are normally ejected by the sun, so the resulting image is more balanced than a sunrise image would be. I think the darkness of the desert also played a part in making the moon appear more powerful than it might have elsewhere.

I dropped the focal length again to 50mm and while the horizon still had the warm glow of a sunrise, the deeper blue of the sky above and twinkling stars began to shine through. While the Moon at perigee was about about 14% larger, and 30% brighter than the moon at apogee (farthest point in its orbit from the Earth), it still lacked the overbearing power of the sun to wash out the stars in atmospheric reflectance, which allowed for more detail in the night sky than I can usually get during a sunrise.

I swapped over to the 28-300mm for a few shots to see how well it could handle the difficult lighting conditions. After a final shot at around 60mm led to a similar halo effect around the moon from the heavy atmosphere, I decided to give up for a while and transition to the beautiful starscape still visible on the Western side of the sky behind me.

The sun had finally dipped below the horizon, so the stars were momentarily free to shine. However, even though I was facing away from the moonrise, the brightness of the moon could still be seen in the long, dark shadows it cast across the desert and the Chisos Mountain Range beyond. Modern digital SLRs can pull out more information than our eyes can see, especially with HDR software, but it didn't take much exposure time to get these shots. It was bright enough with just the moonlight for us to walk around without any additional light from our headlamps. As I looked back at the Chisos Mountain Range, I could easily pick up the shifting lights of cars exiting and entering the Chisos Basin via Basin Junction Rd.

From my position on the Bear Box, I also had a good view of our simple campsite, and my buddy Travis enjoying the amazing moonrise with his binoculars.

After taking the shots I wanted from up on the bear box, we were both starved and very ready for a warm dinner. I still had a few shots planned for later that night when the moon was higher and less distorted by the atmosphere, but for now it was time to tend to my non-photographic (and arguably more essential) need to eat.

We set up our camp stove on the rocky ground, and lit the fuel in the chilly night air. Cold drinks in hand, we propped our feet up on the wood log at the back of our campsite and enjoyed good conversation and a warm meal in the glow of the rising Supermoon.

It was a perfect end to yet another fantastic day in Big Bend! However, as is usually the case with me on these sort of camping trips, I would still continue to shoot late into the night long after everyone else had retired.

© 2017-2019 Shaun C Tarpley


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