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Witnessing Nuri (KSLV-II) rocket's successful 3rd launch

Launch of the Nuri rocket on 6:24 PM, May 25, 2023 (KST)
After returning mostly empty-handed the day before due to the scrubbed launch, I set out to Nangdo again on May 25, 2023, to watch the second attempt of the third launch of the Nuri rocket, a.k.a. KSLV-II. The weather was much better than during the first attempt, so I was able to get a mostly clear view of the launchpad and the rocket itself. However, being an evening launch with heavy clouds above still posed some challenges for getting good shots with my Nikon P1000. Fortunately, it worked out well for the most part and I could grab a nice still of the lift-off as you can see here.

Nuri (KSLV-II) in flight shortly before entering clouds
The rocket soared through the sky mostly uneventfully while showing off the flames nicely as you can see here. Then Nuri disappeared into the clouds a mere minute later, so it wasn't possible to witness the stage separation. Still, people were happy to see a good, successful launch in person. I uploaded the recordings of the launch here.

Photo shoot setup
Nuri on the camera screen

Device: Nikon P1000
Settings: 3000mm - ISO 200 - 1/40s - f/8
Filters: Hoya Fusion Antistatic CIR-PL
Time: 2023-05-25 18:24 KST
Location: Yeosu, Korea
Photos processed with Pixelmator 3.3.3

Server moves to Mac mini 2023

The website's new home, the Mac mini M2 Pro
I've been oscillating between Mac mini and iMac for the past two decades for server use. An iMac 21.5" (2017) took over the job of a Mac mini (2012) for the past five and a half years, and now I'm moving back to Mac mini.

This time, it has an M2 Pro processor that uses the ARM architecture instead of Intel x86. So I took my time in setting everything up from the scratch, which took about three weeks. On the hardware side, I wanted to recreate the integrated look of an iMac, so gathering the necessary components required some time. On the software side, there were some compatibility issues in the server components that needed resolving. Most of them are fixed now, so I moved the server operation to the new system today.
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Near-simultaneous solar transit of ISS & Tiangong

The two biggest objects orbiting the low earth orbit, International Space Station (ISS) and the Tiangong Space Station (a.k.a. Chinese Space Station or CSS) can be seen transiting the Sun every now and then. But because their orbital characteristics are different, it's hard to see the two like that on the same day within the 200 km range. And it's much rarer for the two to be seen in front of the Sun at the same time. But earlier this month, I found out that I could see the next best thing - seeing the two make the transit from the same location within 14 minutes of each other.
Composite of ISS and Tiangong passing in front of the Sun on 11 AM, April 7, 2023
The result of this observation is shown here as a multiple-frame composite. Thanks to the weather, both space stations were photographed clearly and you can make out their distinct shapes - the less dense one is Tiangong. And because the observations occurred within a short timeframe, it's easy to gauge the relative apparent size difference between each other.
Comparison of the ISS and Tiangong's apparent size
Close-ups of the two space stations make this more apparent. The ISS was 53 arc-seconds wide at 521 km away, while Tiangong was 37 arc-seconds wide at 460 km away. The difference in distance shows that Tiangong's orbit is lower than that of ISS. In fact, Tiangong's nominal orbit is around 375 km, while ISS is at about 420 km.

If the ISS was observed at the same distance, it would have been 60 arc-seconds wide. This means that Tiangong, which was fully built a few months ago, is roughly 60% as wide as the ISS and much bigger than what the transit finder website claims. I think that it's showing the size of just the core module (Tianhe), not the entire structure.

Maybe if I get lucky I will be able to spot the two making the transit at the same time in the future. Until then, I'll keep looking.

Device: Nikon P1000
Settings: 3000mm - ISO 200 - 1/1000s - f/8
Filters: ICE N100000 (Neutral Density 16.5 Stop)
Time: 2023-04-07 11:00 - 11:14 KST
Location: Dangjin, Korea
28 photos (14 each) processed with Pixelmator 3.3.2, RegiStax, and PIPP 2.5.9

Total lunar eclipse with Uranus occultation

Total lunar eclipse seen at Naju on the evening of November 8, 2022

This year's lunar eclipse was a long one, with the added bonus of having Uranus occulted by the Moon during the totality. This doesn't happen very often, and the next one is supposedly more than 200 years away. So I prepared my equipment and observed the progress at a good spot near home.

Moon's occultation of Uranus at 8:20 PM, November 8, 2022

I did have some difficulties during the 4-hour session, as one camera battery couldn't last that long and dew was building up on the lens after 9 PM. But using a camera with a powerful zoom worked great for capturing the Uranus approaching and then hiding behind the Moon. It was literally a once-in-a-lifetime observation.

Device: Nikon P1000
Settings: 1500mm - f/6.3 (ISO 800 to 1600 / 1/3 to 1/250s)
Filters: None
Time: 2022-11-08 18:07 - 21:40 KST
Location: Naju, Korea

Interview with Monthly National Assembly Library

Cover for the interview at Page 44, July-August 2022 issue, Monthly National Assembly Library

I had the opportunity to be interviewed by the people who make the Monthly National Assembly Library magazine. I talked about all sorts of topics, including what I do these days, the book about electric vehicles that I wrote last year, and the rocket launches. The photos of myself came out quite well, especially the cover photo for the interview as you can see here.

The full interview (in Korean) is available in digital form at the National Assembly Library website here:

- Monthly National Assembly Library

Select "2022년 07ㆍ08월호" from the dropdown list and find the third "인터뷰" (7th item).

- Direct link to the interview pages

I'd like to say big thanks to the interviewers who come all the way to Naju to hear me talk.
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