Latest Comic : Thursday, July 9. 2020

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Spotting the SpaceX Crew Dragon spaceship

International Space Station as seen in 2015 and 2020

SpaceX Crew Dragon launched on May 30, 2020, under the mission name DM-2, became the first privately operated spacecraft to reach the Int'l Space Station with a human crew. It is now docked to the Harmony module at the forward end until around August, which makes it possible to be seen when the station is overhead. I made some attempts to photograph it, and these are the first clear results coming from the space station's transit in front of the Sun.

ISS passing by (click to enlarge)

With a distance of 448.9 km, the station would have an angular diameter of 61.6", which made it easier to notice the docked spacecraft in question. You can clearly see the difference when you compare the new photos to the one I took 5 years ago, when another SpaceX spacecraft, the Cargo Dragon, was berthed to the bottom of the Harmony module (and thus not distinguishable from the overhead view) for the CRS-6 mission.

Nikon P1000 takes photos of the Sun behind Bolt EV

To take these photos, I drove to Hamyang on my Bolt EV. It was about 100 km away from home, but the weather was excellent and I didn't want to waste a good opportunity. I was glad that everything went right. The photo from 5 years ago is an enlarged composite of multiple frames took by an iPhone through a telescope. But it seems that a single photo taken by Nikon P1000 on its own surpasses that with proper focusing, even though the setup is much simpler and lighter. I guess I'll be bringing around the camera to more places.

Device: Nikon P1000
Settings: 3000mm - ISO 200 - 1/2500s - f/8
Filters: None
Time: 2019-06-22 13:53:20 KST
Location: Hamyang, Korea

Solar eclipse of June 2020

Progress of the solar eclipse observed in Naju on June 21, 2020 (8.3% size)

With today's solar eclipse the third visible in Korea in less than two years, the phenomenon felt somewhat common. But there won't be one happening around here for the next ten years so I hoped to catch a good glimpse of it. Sadly, it was pretty cloudy and the Sun was blocked much of the time, making continuous observation from home impossible. I did my best anyway and you can see the progress here, complete with the brush of clouds.

Nikon P1000 tracked the Sun through the cloudy sky

Device: Nikon P1000
Settings: 2400mm - ISO 100 - 1/25-1/250s - f/7.1-8
Filters: None
Time: 2019-06-21 15:53-18:03 KST
Location: Naju, Korea
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Scorpius constellation amidst the Milky Way

Scorpius constellation in the southern sky as seen by iPhone 11 Pro

The local sky had been clear for the past few days and it was a good chance to test the capability of the iPhone 11 Pro's Night Mode as an astrophotography tool. With a tripod, the exposure time in that mode can be extended to 30 seconds, paving the way for some basic long-exposure shots of the night sky.

For my first target, I chose the Scorpius constellation which would be in seen in the south after midnight. If the sky was particularly dark, the Milky Way would appear as the backdrop. Light pollution situation isn't getting any better around here, so the results from my iPhone weren't impressive even though the southern sky was the darkest.

To make the best of it, I took multiple shots, merged them together, and increased the contrast to make the stars stand out as you can see here. You can even find a hint of the Milky Way slightly to the left of the center. The brightest star of the constellation, Antares (Alpha Scorpii), is visible just above the star on the dead center (Tau Scorpii).

Device: iPhone 11 Pro
Settings: 26mm - ISO 5000 - 30s - f/1.8
Filters: None
Time: 2020-05-14 00:48-00:53 Korea Standard Time
Location: Naju, Korea
8 photos processed with Pixelmator Pro
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How does temperature affect Bolt EV's efficiency?

Efficiency-Temperature Correlation of Bolt EV (February 2019 to January 2020)

I keep a detailed log of my Bolt EV drives to gain insights to the questions I wanted answers to. One of them was this feeling that the drivable range was getting lower on a cold day despite the fact that I drive without having the heater on. Since my EV driving habits became consistent after driving for about half a year, I decided to analyze one full year's of driving from February 2019 to January 2020 to spot a trend between the ambient temperature and the car's efficiency ("fuel economy").

The results above speak for themselves. Even if you don't use a heater, the car's efficiency will certainly drop as the outside air gets colder. This is largely because the air itself becomes more dense, increasing resistance. Using a heater will impact efficiency on top of this. Meanwhile, driving at an average trip speed of about 50 km/h (30 mph) yielded about 1 to 1.5 km/kWh better efficiency than at about 80 km/h (50 mph). Again, less air drag meant better outcome.

If you want to know how the data points were chosen, please read on.

Road Type Speed Limit
(km/h)
Minimum
% of Trip
Trip Range (km) Speed Range (km/h)
Min Max Min Max
Expressway 100 - 110 75 112.7 364.8 70.4 90.0
Intercity 70 - 90 19.6 25.3 40.6 69.0
My two most common driving patterns happen on expressways and intercity roads. The former are usually for the long distance family trips. The latter are used in the routine errands between Naju and Gwangju for groceries or movie-going. Downtown driving is done mostly by my wife and there are no records of time or temperature, so they were not analyzed.

As all trips start and end within cities, the most significant and fastest road type used must take up at least 75% of the entire distance for a sample to be representative of a type. And to minimize impacts of traffic jams, average speed of a trip had to be at least 70 km/h for expressway and 40 km/h for intercity. Driving under rain or snow were also out in order to avoid other weather factors. Additionally, expressway trips had to be at least 100 km long and the intercity trips had to have no significant deviations from the most common 22 km-long route I take. Use of heater was completely avoided, while air conditioning was used very sparingly if needed and took up less than 1% of the battery consumption.

Road Type Total Trip
(km)
Average Data Count
Trip (km) Time (H:M:S) Speed (km/h)
Expressway 9,036.7 251.02 3:10:03 79.25 36
Intercity 1,593.1 22.13 0:26:20 50.41 72
In the end, 108 samples spanning a total distance of more than 10,600 km were chosen out of the 27,000 km total distance covered during the period. The real life driving conditions did still create some variability, but the trends were clearly present. I can now use this analysis to better plan for future trips.
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Annular Solar Eclipse of 2019

My Nikon P1000 was set up on the roof of the Marina Barrage along with other cameras and telescopes

An annular solar eclipse happening on the Boxing Day in Singapore sounded like a great excuse to have a year-end family trip there, so I acted on it. As expected, multiple venues across the city-state provided spots for people to view and photograph the phenomenon. I picked Marina Barrage as it would have longer totality and snacks.

My family arrived nearly two hours before the start, but a lot of equipment were already on the roof. Once our stuff was set up, my daughters saw the Sun through the handheld protective film or binoculars while I took photos in intervals.One thing that concerned me was the weather, as it was supposed to be cloudy with a chance of rain that day. While the sky was mostly clear during the early stages, clouds began to build up as we neared the totality.

Progress of the solar eclipse observed in Singapore on December 26, 2019

The clouds were both a curse and a blessing. It became cumbersome to track and photograph the Sun through the camera on the tripod, since I needed to fiddle with the settings every now and then. But the clouds often became just thick enough for my iPhone to take the ongoing eclipse directly without any filters, letting me get these nice photos you see above. As a result, both the phone and the camera had their share of the action.

Celine was able to see the eclipse in the morning (left) but clouds obscured view in much of the afternoon (right)

The clouds that moved in about half way through the 2 minutes of totality created a breathtaking view - people could see the "ring" of Sun with naked eyes. That was quite an experience. Alas, the clouds blocking the Sun became thicker and more frequent after that, so they became much more annoying in the second half of the eclipse. I was getting a lot more gaps in the interval photos I was taking, so I finished my session about an hour early and went sightseeing around the Marina Bay with my family to much satisfaction.

Device: iPhone 11 Pro
Settings: 52mm - ISO 20-25 - 1/23810-1/564s - f/2.0
Filters: None
Time: 2019-12-26 12:09-14:25 UTC+8
Location: Marina South, Singapore

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