As described in my last post, I was inspired by an APOD entry last December featuring a solar analemma captured by a security camera on someone's driveway to create my own timelapse video tracing the path of the Sun over a year, capturing the distinctive figure eight shape of the analemma as the shadow moves day by day. This project recreates a technique used for timekeeping, calendar making, and as the basis for religious and cultural rituals going back thousands of years. But as with the APOD that inspired it, I'm putting a modern spin on this ancient concept by leveraging programming, computers, digital cameras, photo and video editing software, design software, and 3D printing. In this post, I'll provide an overview of my setup, including how I planned out the project, created a custom gnomon (the part of a solar timepiece that casts the shadow), set up the camera and automation system, and the initial image processing and results.
Decision #1: What to Shoot With
Blink camera
First off, I had to pick a camera to capture each image with. As the subject is outdoors - and the project lasts for a year - using a DSLR like my Nikon D750 wouldn't be feasible. I could easily dedicate one of the IP cameras I have for a year but they aren't weather-proof and they have to be plugged in. Luckily, we have a set of Blink outdoor cameras around the house. They are weather-proof, battery-powered and can be accessed over a network connection. The only concern I had with them is the mount is easy to move which could interfere with having the same point of view for every image over the course of the year. I solved that by 3D printing a new mount that I could lock in place with a set screw.
Decision #2: Where to Shoot
My first thought was to do something like in the referenced APOD... shoot to the north with the shadow to track being cast in front of the camera with the Sun shining from behind. I even considered mounting the camera so that its own shadow would be what traces out the analemma. However, while our house faces north-northeast, we have 6 huge cedar elm trees out front; during the summer any shadow cast from the edge of the house would be lost in the shade of the trees. Given that, I settled on shooting in the back yard.
Decision #3: When to Shoot
View to be captured
The decision of when to shoot and where to shoot go hand-in-hand. Deciding to shoot in the back yard was fine but incomplete till I figured out what time of day to shoot. Long story short, as we already have a Blink camera on our side fence, I figured out that as that fence runs on a line that's about 153 degrees (approximately south-southeast), I could shoot at just after noon each day and the shadow would trace out the figure eight of an analemma on the ground just on our side of the fence and in the field of view of that camera.
Decision #4: What to Shoot
Gnomon on fence
Although I could have mounted just anything on top of the fence to cast a shadow, I took advantage to having access to a 3D printer and designed and printed my own gnomon in the form of a stylized Sun mounted on a post. It was printed in black but I took yellow Plasti-Dip both for a "sunny" look and also to give it a bit of additional protection against the elements.
Decision #5: How to Shoot
Early photographic attempts to capture a solar analemma in the sky with a film camera required incredible dedication, shooting at the exact same time of day, one day a week or every few weeks for an entire year. Because I am creating a timelapse video rather than a composite photo, I need to capture an image more frequently (every day) so I decided to automate the process. I have a home automation solution called Home Assistant. With it, I was able to write a script that takes a photo with the Blink camera in the back yard at 12:30pm (1:30pm during Daylight Saving Time) every day. The system also records metadata about weather conditions (overcast, sunny, etc.) in a text file, storing both the images and data on a home computer for later use in assembling the video.
Progress To-date
Although I only recently began posting about this project, I started planning it in December and started shooting the day after the winter solstice which fell on December 21st. Things are going well but there have been a few bumps in the road:
It turned out that the shadow cast by the first gnomon I created was a little too small so I redesigned a larger version and replaced the first one with it at the end of December.
Although the camera mount is locked in place, it appears that the image framing shifts a very small amount over the course of several days. My guess is that the weather going from sub-freezing to springtime temperatures, the plastic mount is expanding and contracting, affecting the alignment of the camera. Thankfully, the difference from image to image is small enough that I can align all the images using Photoshop so that they don't shift from day to day.
Early on, rain left water drops on the camera lens that affected the images but we've had quite a bit of rain since then and it hasn't happened again. If it does, I may need to add a hood to the camera mount.
In spite of these issues, my first pass at assembling the images into timelapse format looks promising. This version has two sections. In the first, watch for the yellow dot on the ground... it overlays the gnomon's shadow. In the second section, watch that same area of the ground and you'll see the shadow of the gnomon trace out the beginning of an analemma.
Timelapse showing 6 weeks of daily shadow captures (with gnomon shadow highlighted and with raw video)
As you can see, at just 6 weeks, there is not enough of the analemma yet to make out its distinctive figure eight shape but a pattern is beginning to take form. And there are some oddities in the video - gaps from overcast days (and some rain) and other things moving besides the shadow cast by the fence and gnomon (leaves, chairs, our dog, etc.) - all things I expected given my past experience creating timelapse videos.
But how exactly did I create the gnomon? What tools did I use to automate the daily image capture? And what techniques am I using to process and align the images? To create the video? In my next post, I'll dive into these technical details and more, sharing the nuts and bolts of my analemma timelapse setup for those who want to explore further.
Update: One Year Later
Having had an issue with the video camera a month or so after this post was originally made, I've postponed wrapping up the project, intending to have the final video run from the June solstice of 2025 through the June solstice of 2026. Stay tuned!
UPDATE: Now that I've had time to work on some of my other images and videos, I went back and remixed this one to fix some things I rushed the first time around. In this edit the sky appears darker, closer to what we saw that day, so the coronal ring around the Sun stands out better.
Another total solar eclipse imaging projects I planned to do is a timelapse sequence of the eclipse. In 2017 I tried shooting the entire eclipse but this time I just focused on the 5 minutes before totality, the 4+ minutes of totality and the 5 minutes after. Unlike 2017, we had much clearer skies and this came out pretty much just as I planned. Thanks to Alan Dyer (amazingsky.net) for the tips in his book on shooting the eclipse, specifically the tips on shooting a wide-angle timelapse!
To capture this, I set up my son Brian's Nikon D750 with our Irix 15mm f/2.4 wide-angle lens on a tripod at the corner of my son Chris' yard where we were observing the eclipse. My D750 was in use on the telescope so a big thanks to Brian for the use of his camera!
The sequence was shot with the internal intervalometer set to capture an image every second for 15 minutes with the timer set to start it at 1:35pm so that I didn't have to remember to start it on time. I set exposure ramping on so the camera would automatically adjust the exposure as the sky got darker and brighter, then set the exposure compensation to +1.33 so that it wouldn't be heavily overexposed during the pre- and post-totality shots.
Once at home, I processed the 900 images in LRTimeLapse and Lightroom Classic to create a video clip from the images and then added titles, adjusted track speed and added music in DaVinci Resolve. This is the finished product!
A few things to watch for in the video:
At about the 18 second mark, look for the small star to lower right of the Sun. That's not a star, it is the planet Venus!
The contrail at lower center is probably a commercial aircraft, possibly one of the one flying along the eclipse path to prolong how long they could watch totality.
At about the 36 second mark, the "insect" flittering about above us in the drone landing after shooting the arrival and departure of the lunar umbra.
Building on the project described in my last post which involved creating a camera obscura out of a bedroom with our grandkids Olivia and Jack, we have taken the project to the next level: video!
For this, we used Olivia's pinhole lens which with its larger aperture allowed shooting shorter exposures. That let us maximize how many frames we could capture in a given amount of time. I re-framed the view in my Nikon D750 to take advantage of the wall space on the right and we then set it up to take one ten-second shot every 12 seconds. At the end of an hour and 10 minutes, I stopped the camera, having taken 348 images.
The next step was loading the images on the computer, cropping to a 16:9 ratio and adjusting the exposure a little in Lightroom plus inverting them vertically, then using LRTimelapse to render a 4K video. The last step was adding titles and music (Pounded Piano by Podington Bear) in Da Vinci Resolve.
This was shot at a busy time in the backyard, with our Weimaraner Luna coming and going and with the grass being mowed. The timelapse also captures clouds floating by and the shadows of trees and such moving.
Although the clouds interfered with getting a clean telephoto image of the full Strawberry Moon of 2023 above Reunion Tower in Dallas (my original goal), I was still able to capture this sequence of it through the clouds as it rose over downtown just after sunset on June 3rd.
This is 34 minutes compressed into about 12 seconds. Watch center-frame and you'll see the moon just peak through the clouds and then pop in and out through to the end, tracing an arch up and above Reunion Tower.
Timlapse sequence captured with a Nikon D750 and Nikkor 24-120 lens at 40mm, shot from Trammel Crow Park on the Trinity River. Processed with Lightroom Classic, LRTimeLapse and Da Vinci Resolve.
See my shot of the Strawberry Moon over downtown last year here.
Music is Time's Up by Loopop, YouTube Media Library.
In my last post, I described my efforts to capture an interesting image with the Moon and all five naked-eye planets lined up in the order of their orbits out from the Sun. As the conditions on June 24th were not ideal and elusive Mercury was mostly lost in the haze over Downtown Dallas, I tried again on Sunday, June 26th. The sky was much clearer (at least over the Dallas skyline) and there was less haze. Thankfully, staying up almost all night a second time was definitely worth it!
In the image above, I've added an enlarged insert of each object and labeled them to give everyone a more clear idea of what they are looking at without having to click on the image to see it full screen and then zoom in to tell what each object is. The original, unlabeled image is also included below.
While the surprise on Friday's outing was the ISS flyby (I'm still working on the timelapse videos from both Friday and Sunday), the surprise in these images is that I also captured the Pleiades star cluster (M45), which you may know as the Seven Sisters (immortalized in the Subaru logo)!
Another difference between this image and the one from the 24th is that the Moon is "older", now 28 days through its cycle (vs. 26 days on the 24th). Just two days from being a New Moon, in this image it is a thin crescent, only 4% illuminated. However, thanks to the length of the exposure (2 seconds), the camera captured not just the sun-lit crescent but it also captured earthshine, the portion of the Moon not in sunlight but still lit but the sunlight reflected off of the Earth.
For anyone interested in how this image was created, I started out by taking multiple shots with a Nikon D750 and the kit lens, a Nikkor 24-105mm f/4 lens set to it's widest at 24mm. Each of the 6 images used were taken in portrait orientation and, using a tripod, I started shooting to the left of Mercury, then moved the camera about 35 degrees to the right so that the next shot would be overlapped with the previous, continuing until I had the final shot including Saturn. Each image was taken at ISO 200, f/4 and as noted above, exposed for 2 seconds. The screenshot to the right was my shooting plan from PhotoPills with the red dot representing my location on the west levee of the Trinity river and the black dot representing the Bank of America Plaza tower (the tallest building in Dallas, the one in the panorama with the bright green lights), about 1.6 miles away. The Margaret Hunt Hill Bridge, the white suspension bridge arch in the center of the panorama, crosses the Trinity. The lighter dashed lines with black dots represent the left, center and right of the field of view in the panorama.
Post-processing involved using software (Adobe Bridge and Adobe Camera Raw) to merge the 6 shots into one panorama, then crop and apply adjustments for exposure, sharpness, etc. Next, I edited that image in Photoshop to add the insets and labels. As the merged image exhibited some color banding in the morning twilight sky, I used a technique involving adding a little noise to the image to reduce the banding. Note that I also took some creative license with this shot, editing the inset of the Pleiades to emphasize the major stars so it would be more recognizable.
As always, click an image to view full-screen. Enjoy!
Step outside this morning about 45 minutes before sunrise and you would have seen an incredible sight, a unique alignment of the visible planets along with a waning crescent Moon. It's not all that rare to see some combination of planets before sunrise or after sunset but it's pretty rare for them to be aligned in the order that they occur extending out from the Sun: Mercury, Venus, Mars, Jupiter and Saturn. Even more so with the Moon in view.
There's nothing special or mysterious about this alignment. It just happens that the relationship between Earth and each of the other planets in their orbits around the Sun is such that they line up this way now. But isn't it beautiful!
I had originally planned to go find a spot out in the countryside with dark skies to take this shot but just the Moon and planets on their own with nothing interesting in the foreground seemed a bit boring. I did a number of test shots over the past week and determined that even with the bright lights of downtown Dallas, they would still be visible in a shot like this.
Unfortunately, the haze was just a bit too heavy this morning for Mercury to really show up. It's there but just hard to see without zooming in really close. Given how close the planet orbits the Sun, it is never that far above the horizon while the sky is still dark enough to see it. I have some other shots I still need to go through though so if I have another where it's more visible, I will post it.
This image was created by taking four shots with a 15mm wide angle lens. Two were taken with the camera level (to avoid vertical distortion of buildings, bridges, etc.), one aimed just left of the Margaret Hunt Hill bridge (the brightly lit suspension bridge) and the other aimed towards the bright street light to the right. The other images were taken in the same directions but aimed high enough to capture Jupiter and Saturn. The four images were merged as a panorama in Adobe Lightroom.
The panorama above is only part of what I was working on this morning. I also captured nearly 3000 shots over almost 3 hours that I plan to assemble into a timelapse video. The image to the left shows the shooting setup. The camera on the left is my Nikon D750 with a 14mm Rokinon lens; it's taking the timelapse sequence of images. The camera on the right is my son Brian's D750 with our Irix 15mm lens; it's what I used to take the shots for the panorama.
Stay tuned for the timelapse! Besides the Moon and planets, it features a special guest appearance from the ISS.
As mentioned in my last post, I used my Nikon D750 DSLR mounted on a Sky-Watcher Star Adventurer tracker to capture about 5 hours of the partial lunar eclipse. Here is a preliminary time lapse video.
This sequence is just from the shots exposed for the sunlight face of the moon. I'm working on another sequence with full lunar surface, blending shots exposed for sunlight and shadow. The blended shots will showcase the redness of the lunar surface at mid-eclipse. They will also include the Pleiades and a tighter crop.
The movement of the moon in this sequence is not due to its movement across the sky but the moon drifting out of center-frame due to the polar alignment of tracker being a little bit off. I'm still working on a process to re-align the sequence and to rotate the view for a more natural orientation of the sky.
When watching the video, be patient as there are a few seconds in the middle where it goes black. The shots used in this video were taken at f/6.3, 2500th of a second, ISO 800. It turns out that was slightly underexposed for a sunlit lunar surface during the phase where the Moon was mostly eclipsed, I missed capturing the portion of its surface still reflecting sunlight so nothing shows up.
More to come...
BTW, for a better view, select full screen (box icon, lower right) when playing the video.
In the early morning hours of November 19, 2021, a lunar eclipse began. As a partial eclipse, it normally might not have been noteworthy. What brought a lot of media attention about this one is that it lasted just a shade over 6 hours. It's been 1000 years since the last time a lunar eclipse lasted that long.
The timing for this eclipse is such that the Moon was almost at apogee, the point where it is furthest from the Earth in its orbit, and since a body in orbit moves slower the further it is from the body it orbits, the Moon spent more time in Earth's shadow. It also meant that the Moon was smaller in appearance so this was the opposite of a "Super Moon".
The other interesting thing about this lunar eclipse is that the Moon is within a few degrees of the collection of stars known as the Pleiades or the Seven Sisters. As both were high in the sky during most of the eclipse, the cold dry air we had in North Texas that night made for great viewing.
Initially, my plan to capture the eclipse was to shoot with my Nikon D750 using the longest lens I have and the Star Adventurer sky tracker to capture shots of the lunar face throughout the night to create a timelapse video. However, given the close proximity of the Pleiades, I decided to shoot with a shorter lens and include it in the view.
I won't go into the technical details but given this was really the first time I had used the Star Adventurer for tracking more than a few minutes, I shot a bit wider view than I probably needed to so the Moon is rather small in the frame. The bad news is that the tracker was a little off and so the Moon didn't stay centered in the frame. The good news is that with the wider view, both it and the Seven Sisters were in-frame throughout the 5 hours of the eclipse I captured.
Here is a frame from about mid-eclipse. I'll post more as I get further through post-processing all the images.
The journey continues beyond 2009... check it out!
