I like long exposure photographs called solargraphs. Photo-sensitive paper is put inside a light-tight container. A pinhole in the container allows an image to be formed on the paper after a very long time. My first attempts were described here. If the Sun shines into the pinhole, it traces a bright line across the paper as in this day-long exposure.
Everyday the Earth moves some distance around the Sun in its orbit, shifting the position of the Sun in the sky. The Sun traces in a solargraph also shift a little each day. Our front window faces east toward sunrise. I exposed a solargraph to those sunrises with hopes of seeing the Sun’s movement toward the south over a long period of time.
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Perhaps you’ve heard the phrase ‘Never in a month of Sundays’. I offer you a month of sunrises between 30 Aug and 26 Sep 2019 out my front window. Bright streaks were caused by the sun shining through the hole of the pinhole camera onto light sensitive paper. Missing sections were caused by clouds blocking the sun. The streak farthest left was from 30 Aug. The one farthest right was from 26 Sep just after the autumn equinox when the sun rises directly east.
A solargraph of the same scene was made during a week back in late May which yielded this set of lines. East is in the center of the image. Northeast is the left edge and southeast is the right edge of the view.
Using Photoshop Elements, I copied the May exposure onto the more recent one to illustrate how far the sun had progressed south as the summer ended. It will track even farther as it moves into the winter months reaching its most southern position at the winter solstice. The pinhole camera is currently set up to record for the next 3 months.
More information about solargraphs can be found at this post.
It is rare to have five consecutive nights of clear skies for star gazing. And, even more rare when those nights coincide with a special event I hope to photograph. The gods must have looked favorably on me. It started on 11 July 2019 with this view to the south-southeast at 9:44pm CDT. Far lower left was Saturn emerging from behind the bushes. Jupiter was proud above the trees. The overexposed Moon hovered at the right. I photographed this scene at 9:44pm over the course of the next four nights. The Moon tracked down to the left. Click for a better view.
ISO 800, Exposure 1 sec | Click to embiggen.
I photographed a satellite flare the evening of 10 June 2019. As the exposure was being recorded, a low flying airplane moved through the frame with lights blinking . It was fun to see. I had another opportunity to photograph a flare on 7 July. This time something else flew through the frame with lights blinking.
First, what I expected to see in shown in this chart from CalSky. The site emails me with alerts about coming events such as ISS passes or satellite flares. The field of view is toward the north and pointing almost straight up. The North Star, Polaris, is not visible but just off the chart at the bottom. The Big Dipper is at the left with the two pointer stars of the dipper pointing to Polaris. Satellite Metop-A was to pass through this field at a specific time. A reflective panel on the weather satellite was to direct a beam of sunlight down to my location for a few seconds. The grey circles show the pattern of bright-to-dark of the beam. It was to last a few seconds.
As the time of the pass neared, I set my iPad so it was pointed north and tilted up above Polaris. I opened the NightCap app and set it for a long exposure. I watched the sky during the 212 sec exposure and never saw the satellite flare. It must have been more dim than predicted. I went inside to see if anything was visible on the image.
The Big Dipper was easily visible. Short star trails were obvious during the 2.5 minute exposure. The flare was barely visible so I enhanced it with software (top center). Also visible were a few trails and spots of light that didn’t fit the pattern of the stars. Those were fireflies. Two of them were fairly close to the iPad and left bright long streaks (small squares). One was far away and blinked several times as it made a looping pattern (lower right). Click the image for a bigger view.
If you have followed my blog long enough, you might recall that I like to photograph Iridium flares. Link to examples. The constellation of 66 communications satellites provides a worldwide phone system. I get email notices when a flare, sunlight reflecting off an antenna, is visible at my location.
Recently, I have received notices about flares from three weather satellites of the European Union (EUMETSAT). They are known as Metop A, B, and C. Their polar orbits and altitude allow weather to be monitored continuously. Antennae sometimes reflect bright sunlight down to Earth causing a flare. I was notified of one at 9:54pm local time on 9 Jun 2019.
Using the NightCap app on my iPad, I set it on the sidewalk, angled it toward the correct part of the sky and let it capture a time exposure for a couple of minutes. A small plane flew over at low altitude just after I started the exposure. Right after that, the Metop-C satellite passed over leaving a faint flare trail. Both were going north, lower left. Notice the handle of the Big Dipper drawn in the top left. The two pointer stars of the dipper are not visible. I like when serendipity happens.
I stepped outside and looked up toward the sun. An arc of faint color caught my attention. It was actually a full circle of color around the sun. These halos are 22˚ in radius from the sun caused by refraction of light through ice crystals of the high cirrus clouds between me and the sun. The color saturation has been enhanced a little to show the redness of the inner edge and blueness of the outer edge due to their different wavelengths of light.
I went out several minutes later. The cirrus clouds were gone, as was the halo. It was my lucky day.
Another weeklong ‘snapshot’ exposure is finished. Four previous solargraph posts are here. The pinhole camera can was sitting on the wooden floor of the deck facing west. During several of the days the sky was clear which allowed the path of the sun to trace nicely down to the right. The traces are still shifting north (to the right) each day as we progress toward the summer solstice in late June.
The light-sensitive photo paper was put on a flatbed scanner to capture the image above. For the image below, Photoshop Elements was used to invert darks to lights and lights to darks.
The software was then used to convert to a greyscale image. Our weather this spring is still unsettled. The deck furniture is covered under a tarp at the right. The trees are beginning to leaf out. The boards of the deck floor are visible at the bottom. Curvature is accentuated because the image paper is wrapped halfway around the inside of the metal can.