Wesley's Tool-Box

It seems that I get to see a "great" transit of the ISS in front of the Sun once every year, with the space station appearing large enough to make it look like the letter H. This time, CalSky was predicting a nearly perfect condition at Naju, a near-center pass with an apparent diameter of more than one arc minute (63.1"). With the weather cooperating, I did not want to miss it.

To make sure I did not miss anything, I took out both my Celestron telescope with the smartphone adapter and my SX50 HS camera. I was hoping that at least one of them would catch the occurrence. I hurried with the setup and had everything ready just barely. I let my iPhone 6 Plus start recording the view through the eyepiece of the telescope in 240fps slow motion video, and pushed the shutter on my SX50 HS in continuous shoot mode, all mere moments before the transit.


The SX50 HS captured just one frame, which was sort of expected. The quality was easily better than my previous attempts thanks to the large apparent size. But the real deal was in the iPhone 6 Plus. It had captured 80 frames of the ISS in motion in total, with each frame besting the SX50 HS's efforts. The 240fps video capture truly shined, creating this smooth slow motion video as a result.


Here's the stacked and post-processed composite of the video in a single picture; click it to see it in full resolution. You can appreciate the details of the ISS and the sunspot AR 12339 quite better this way. If you look at the space station up close as seen in the first picture of this post, it's good enough to identify its major features. I've marked them for your convenience.

Telescope: Celestron NexStar 6SE + 25mm eyepiece + 2.5x barlow
Device: iPhone 6 Plus (afocal)
Settings: 29mm - 1280x720 - 240fps - f/2.2
Filters: None
Time: 2015-05-10 13:33:58 KST
Location: Naju, Korea
Stacked with RegiStax 6.1.0.8
- #1: 12 photos
- #2: 10 photos (ISS, each) / 100 photos (Sun)

Yesterday evening presented a rare opportunity of viewing the sun-lit ISS whizzing by the Moon from where I live. Luckily, the weather cooperated and the sky was mostly clear of clouds. I initially set up a telescope to see it, but the apartment window was too limited for it to calibrate in time, so I fell back to using my SX50 HS's zoom capability instead.

A few minutes before the crossing, the space station started to appear on the western sky. So I told my daughter Celine to come over and see the phenomenon together; we watched it gracefully travel eastward. When I saw that the ISS was about to transit the Moon, I let the burst mode of the camera snap 10 photos in rapid succession at 13fps. Then, we kept watching the ISS until it disappeared into the eastern sky.

Checking the photos, I noticed that the dot the ISS was supposed to be was smaller than what was expected according to CalSky, which predicted the transit. Then I looked at the first photo where the Moon got behind the ISS, which showed a "shadow" much longer than the dot. This is when I realized that the dot was the central area of the space station and the shadow was its solar panels. The size mystery was solved.

For those of you who would like to see a full resolution composite of the ISS-Moon transit, [click here] to load the image. It's a bit sad I can't adjust the ISO setting while shooting in burst mode with the camera - I would've like to have it lowered for less coarse images.

Device: Canon SX50 HS
Settings: 1200mm - ISO 800 - 1/1000s - f/6.5
Filters: None
Time: 2015-04-24 19:56:49 KST
Location: Naju, Korea

The roof of the new KPX headquarters at Bitgaram City in Naju is dubbed "Sky Park", so I thought it might be an interesting spot to photograph celestial objects. It is surrounded by small windows, obscuring low altitudes, but a good place otherwise. On the evening of the day after Christmas, a flyover of the International Space Station was expected on a clear sky, so I brought my Canon SX50 HS camera to the roof.

It was very windy and cold, and my bare hands holding the shutter button began to feel numb almost immediately. Luckily, the ISS began to appear on the western sky, so I pointed the camera towards it, helped by the iPhone 6 Plus mounted on the hot-shoe. In the span of about 3 minutes, I was able to take roughly 400 photos of the space station, of which 40% was in good state.

The 25 best shots can be seen here, starting at 18:37:00 and ending at 18:39:44, at about 7-second intervals. During most of the visible flyover time, ISS was turned on its "back", and then "rotated around" around 18:39:00, only to disappear about a minute after. The turnaround point was when it was closest to the observer, about 560km away. The animated version with each frame 5 seconds apart should illustrate this quite nicely.

What I like about this observation is that the ISS was captured on camera more clearly than most of the attempts made in Suwon, except for the direct overhead pass last year. The morning flyover photographed last March shows the opposite turnaround, but was much blurrier. The difference is quite noticeable. Looks like I'll be able to enjoy doing astrophotography even more at this new location.

Device: Canon SX50 HS
Settings: 1200mm (2x enlarged) - ISO 80 - 1/320s - f/6.5
Filters: None
Time: 2014-12-26 18:37 - 18:40 KST
Location: Naju, Korea

This series of images I took of the International Space Station (ISS) seem to explain the "sideways" view of the station I've taken a few times before better. Until the close approach, only the center area is visibly illuminated. At the closest point, the solar panels stretching from top to bottom become apparent.

The panels form the two columns of the "H" shape when viewed from the "front". But in these images, the shape is more like a mirrored "ㅔ". I guess this view can reveal a docking spaceship, if there is one and is big enough.

Device: Canon SX50 HS
Settings: 1200mm (2x enlarged) - ISO 160 - 1/320s - f/6.5
Filters: None
Time: 2014-04-06 20:35 KST
Location: Suwon, Korea
Max Magnitude: -3.6

While I have observed the International Space Station (ISS) making a pass in front of the Sun before, it was at a resort far away from home. Yesterday, I had the good fortune of witnessing a pass right at home. My daughter Celine wanted to help out, so I let her set up the equipment and we went to the parking lot to start photographing. We took the photos of the Sun together, and in three of the frames, the ISS was found crossing in front of the Sun. Here is the composite of the three frames set against the stacked 32 frames I shot in 14 seconds while attempting to capture the transit, both in the annotated and full version.

The last frame was really lucky, as it was taken just before ISS got out of the Sun's disk - 0.1 seconds late and we would have ended up taking two frames instead. SX50 HS's regular burst mode takes a photo every 0.43 seconds, so given the transit time of less than a second, this was the best outcome I could expect.

I do wish the fast burst mode, which can take a photo every 0.077 seconds, could take more than 10 photos at once, though. The transit prediction from CalSky is pretty accurate, but local clock error and human reaction delay can creep in. So I would need it to last at least five seconds or so. I should either wait for Canon to make a superzoom camera that can shoot longer bursts, or install an iPhone 5S, which can do 0.1-second burst shots for several minutes, on a telescope. I'm saying this because I missed the Moon - ISS transit on Saturday while using the fast burst mode.


Anyways, here's the animated version of the transit that illustrates the movement quite well. Come to think of it, this sort of pass would be hard to see in person with binoculars - ISS is tiny and moves quite fast, so unless the Sun is magnified really big, it'd be hard to notice.

Device: Canon SX50 HS
Settings: 1200mm - ISO 500 - 1/1250s - f/6.5
Filters: Baader AstroSolar Safety Film
Time: 2014-03-23 08:57 KST
Location: Suwon, Korea
Base photo: 32 photos stacked with RegiStax 6.1.0.8 (08:57:10 - 08:57:24)
Animation: 5 photos (08:57:16.8 - 08:57.18.5)