Entries tagged as satellite

A more successful tracking of ISS

ISS as seen from Naju in April 12, 2018

After several days of clear skies, clouds have been rolling in for the past two days. Amazingly, they did thin out for a few hours in the evening, enabling me to see the ISS for two consecutive days under good conditions. Tracked observation on April 11 failed due to low battery on the telescope, but I was better prepared on April 12 and made a successful tracking.

The International Space Station was 546km away from me at the closest approach at 19:38:03 (408km altitude, -3.6 mag brightness), so the second photo from the bottom right is representative of this. It is coincidentally the clearest photo I got. You can identify many of the modules - starting from the Zvezda module on the top and moving down, you can see the Zarya module in the center with two radiator panels side by side. On the bottom, you can see the cluster of Columbus-Harmony-Kibo modules in the center, with large solar panels on each end. The bright spot is likely where the SpaceX Dragon spacecraft from the CRS-14 mission is currently docked at.


As I have captured several hundreds of frames, it was sufficient enough to arrange them into this 34-second video clip. I have hosted the file on the website, and it should be watchable on a modern browser.

Telescope: Celestron NexStar 6SE + X-Cel LX 9mm eyepiece
Device: iPhone X (afocal)
Settings: 28mm - ISO 400 - 1/1500s - f/1.8
Filters: None
Date/Time: 2018-04-12 19:37-19:38 KST
Location: Naju, Korea
Photos processed with PIPP 2.5.6 and RegiStax 6.1.0.8
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Last look of Tiangong-1 with Iridium 80

Tiangong-1 (top left) and Iridium 80 (center) seen in the northern sky

Tiangong-1, the first Chinese space station, is set to fall back to Earth around April 2. Its orbit had been slowly decaying since its service was ended in 2016. I found out that it would be visible for one last time in the sky this morning, so me and my daughter Celine decided to witness its streak. I set up my iPhone X on a tripod and placed it on the window facing north. Then I launched NightCap Camera app in satellite capturing mode.

Shortly after 5:30AM, Tiangong-1 made its bright (-0.6 magnitude, 181km altitude) appearance from the west, streaking towards east and quickly dimming. Just as it disappeared from our eyesight, another bright flash appeared to the east of Polaris and then quickly disappeared. From my experience I knew that was an Iridium flare. CalSky website verified it to be Iridium 80, showing up at 5:30:36AM with a magnitude of -2.0. We were very lucky to see the two together - since the space station will disappear in a couple of days it was truly a once-in-a-lifetime experience.

On the photo, you can see, starting from the top left and looking towards bottom right, the Tiangong-1, Polaris, Iridium 80, and the Cassiopeia constellation. Click on the image to see it in full size.

Device: iPhone X
Settings: 28mm - ISO 2112 - 61s - f/1.8
Filters: None
Date/Time: 2018-03-31 05:30:01 KST
Location: Naju, Korea

ISS and Rigel as seen by iPhone X

Composite of 50 frames showing ISS making a pass near Rigel (35% size)

The International Space Station was to make a very close pass to Rigel, one of the brightest stars making up the Orion constellation, last Saturday evening where I live. The separation at the closest point was around 0.055°, making it look like the space station passing right over the star to the naked eye. Instead of manual tracking, I decided to fix the telescope on Rigel and record the pass with iPhone X's 4K 60fps video mode. A total of 50 consecutive frames captured the rapid movement. The windy condition, coupled with relatively low angle (35.6°) blurred the results a lot, so I should try this technique again at a higher angle.


Here's the rotated video of the pass, once at the original speed and once at the slow speed.

Telescope: Celestron NexStar 6SE + X-Cel LX 9mm eyepiece
Device: iPhone X (afocal)
Settings: 28mm - ISO 880 - 1/1500s - f/1.8
Filters: None
Date/Time: 2018-03-24 20:00:59 KST
Location: Naju, Korea

Total lunar eclipse of 2018 (Super Blue Blood Moon)

25-photo composite of the 31 January 2018 total lunar eclipse (16% size)

The first total lunar eclipse of this year was an interesting one in that it was a so-called "Super Blue Blood Moon". The visible size is the largest, so it's a Supermoon. It's the second full Moon of the month, so it's a Blue Moon. The Moon hidden behind the Earth's shadow during the eclipse looks reddish, so it's a Blood Moon. This was the first such occurrence seen in Korea since December 1982, so it's not common.

The sky was pretty cloudy all the way to the late evening yesterday, so I had nearly given up on seeing it. But I was in luck and the clouds had started clearing up soon after the eclipse had started. So I hurriedly got my Sony camera and a tripod out to catch the event. It had only half a charge left, but I managed to photograph the progress for two hours, including the deepest point occurring around 22:29. I think it turned out fine - here's the composite photo showing the progress of the eclipse in 5-minute interval.

Device: Sony A5000 + SELP1650 (E PZ 16–50 mm F3.5–5.6 OSS)
Settings: 50mm - ISO 100 - 2s - f/5.6
Filters: None
Time: 2018-01-31 21:40-23:40 KST
Location: Naju, Korea
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Moon-Mars-Venus conjunction of 2017

Moon, Mars, and Venus line up in the western sky

As I dropped by Gwangju to catch a movie (I'll be posting a comic tomorrow), the western sky was adorned with an alignment of some of the bright bodies of the solar system as seen from the Earth - the Moon, Mars, and Venus. The occurrence was relatively well-publicized, but I forgot to carry a dedicated camera tonight. Luckily, the telephoto lens of the iPhone 7 Plus pulled through and I was able to capture this sight over the neighbourhood just before Venus dropped behind the buildings.

Device: iPhone 7 Plus
Settings: 56mm - ISO 1000 - 1/12s - f/2.8
Filters: None
Time: 2017-02-01 21:12 KST
Location: Gwangju, Korea
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