Entries tagged as satellite

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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Supermoon 2016 captured on iPhone 7 Plus

Supermoon on Nov. 15, 2016
Much has been talked about this year's so-called Supermoon owing to the fact that it's the largest since January 26, 1948 and won't be surpassed until November 25, 2034. Closest approach was made on 22:52 KST on November 14 at a distance of 356,509km, about 28,000km closer than average. The resulting difference is hardly noticeable to the naked eye, but is nevertheless a nice occasion to look at the Moon again. Sadly, heavy clouds hid the Moon entirely at that time, so I saw the Moon the next evening, about 20 hours later and used the telephoto lens on the iPhone 7 Plus to take a photo of it. This is perhaps the most detailed shot of the Moon taken using only an iPhone's native camera module.

Device: iPhone 7 Plus
Settings: 56mm - ISO 20 - 1/60s - f/2.8
Filters: None
Time: 2016-11-15 19:06 KST
Location: Naju, Korea
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The streak of Iridium 60's flare

Iridium 60 in the northern sky on August 30, 2016 (14% size)

It's been more than two years since I talked about satellite flares here, but I now have something to show you. As you can see, I had a camera successfully capture the flares coming from an Iridium satellite for the first time. Past efforts used iPhones because I was focused in capturing the motion of the flares. In this photo, the ever-growing Naju Bitgaram City provided a colourful backdrop.

Device: Sony A5000 + SELP1650 (E PZ 16โ€“50 mm F3.5โ€“5.6 OSS)
Settings: 24mm - ISO 400 - 20s - f/4.5
Filters: None
Time: 2016-08-30 05:06 KST
Location: Naju, Korea
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Watching ISS with telescope, 2nd try

International Space Station observed on July 30, 2016
ISS pass, animated

When you try to keep up with fast-moving objects with the manual control of the telescope motors, the lack of fine-grained steps become a big limitation. Speed 6 moves at about 0.267 degrees/second and 7 at 1 degree/second, while the International Space Station moves at a speed that is somewhere in between, depending on the distance. To alleviate this slightly, practice and preparation were needed. I fixed the finder scope misalignment and added a camera mount to the telescope. iPhone 6 Plus was placed on the mount to act as a secondary finder scope, much like what I did on my Canon SX50 HS camera three years ago. These made it much easier to have the telescope point at the International Space Station.

As a result, I managed to photograph about 220 frames of the station in two minutes this time, enough to show the movement like the one I did with the old camera two years ago when I came to Naju. The space station was farther away and a lot dimmer (504km vs 685km, -3.5 mag vs -1.6 mag at culmination) than the previous attempt with the telescope, meaning less details. Even so, I think I was able to identify the SpaceX Dragon spacecraft that went up for the CRS-9 mission, which was attached to the bottom of the Harmony module just ten days before.

Telescope: Celestron NexStar 6SE + X-Cel LX 9mm eyepiece
Device: iPhone 6S Plus (afocal)
Settings: 29mm - ISO 720 - 1/1400s - f/2.2
Filters: None
Date: 2016-07-30 KST
Location: Naju, Korea
Stacked with PIPP 2.5.6 and RegiStax 6.1.0.8

Photos: 10 / 9 / 12 / 6 / 9 / 12 / 28 / 4 / 10 / 14 / 8
Time: 20:18:58 / 20:19:07 / 20:19:12 / 20:19:26 / 20:19:39 / 20:19:41 / 20:19:45 / 20:19:50 / 20:19:58 / 20:20:06 / 20:20:12

Tracking ISS with a telescope

International Space Station observed on June 17, 2016

Directly imaging a fast-moving object in the sky like ISS by tracking it manually becomes more difficult with higher magnification. I could barely manage it with the Canon SX50 HS camera with 1.46"/pixel resolution. Using iPhone 6S Plus on the NexStar 6SE telescope with a 9mm eyepiece gives 0.31"/pixel resolution, making the field of view nearly 5 times narrower. Indirect method, which images the moment when the ISS passes in front of another celestial object, is easier because the telescope is focused on a fixed location. This is what I did a year ago. But such opportunity is much harder to come by, so I eventually decided to give the direct method a try with the telescope.

There were many uncertainties, such as what camera settings I should use on my iPhone and whether the telescope's motors would be fast enough. I would have to make guesses and hope for the best. To increase the chances of catching the moments at a high resolution when it entered the view, I used the 4K (3840x2160, 8.3MP) 30fps video recording mode with highest ISO and fastest shutter speed possible. One thing I did manage to "tie down" was the iPhone itself. The Universal Smart Phone Adapter from Modern Photonics that arrived in the mail just in time was the best solution I tried for attaching the phone to any eyepiece I had.

In the end, I was able to capture 22 frames in total out of about 100 seconds of recording. Targeting the space station with a non-magnified finder scope turned out to be quite difficult and focusing was also somewhat tricky. I need more practice to nail these down better. Fortunately, the motor was more than fast enough and the camera settings worked out. Plus, the processed results already outdid the ones from SX50 HS - major parts of the station are much more recognizable. They also explain what I was looking at in the old blurry shots. Looks like I'll be trying more of this in the future.

Telescope: Celestron NexStar 6SE + X-Cel LX 9mm eyepiece
Device: iPhone 6S Plus (afocal)
Settings: 29mm - ISO 720 - 1/1400s - f/2.2
Filters: None
Location: Naju, Korea (time in KST)
Stacked with PIPP 2.5.6 and RegiStax 6.1.0.8

#1: 9 photos @ 2016-06-17 20:39:38
#2: 5 photos @ 2016-06-17 20:40:03

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