Wesley's Tool-Box

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 16–50 mm F3.5–5.6 OSS)
Settings: 24mm - ISO 400 - 20s - f/4.5
Filters: None
Time: 2016-08-30 05:06 KST
Location: Naju, Korea

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

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

I used the Opteka 2x teleconverter lens for astrophotography for the first time when I took another series of photos of the planets two days ago. This is supposed to be used with telephoto mirror lenses, but that's basically what my telescope is as well and I hoped it would be usable here. Test shots during the day came out alright, maintaining better contrast than the 2.5x Barlow lens I had been using. As you can see here, it performs reasonably well in the night, too.

I didn't originally intend to photograph the Saturnian satellites because they are quite dimmer than the Jovian ones. The four biggest Jovian satellites have apparent brightness in the magnitude 5 range, while the biggest and brightest Saturnian satellite, Titan, is around magnitude 8. The three largest after Titan are of magnitude 10. That's why I didn't take separate photos with longer exposure. Even so, post-processing the background area revealed the dim satellites. I noted their relative positions with the caption. Dione may be barely visible on on well-tuned screens.

Telescope: Celestron NexStar 6SE + Opteka 2x Teleconverter
Device: Sony A5000 (prime focus)
Settings: (3000mm) - ISO 100 - 1/3s - (f/10)
Filters: None
Time: 2016-06-15 00:12-00:13 KST
Location: Naju, Korea
26 photos stacked with PIPP 2.5.6 and RegiStax 6.1.0.8

Yesterday's sky was full of light clouds that became thicker as times passed. It was just enough see very bright stars and planets, so I decided to check how large the planets would appear with my old Tamron 270mm lens on my Sony A5000 camera. Jupiter came out to be about 11 pixels wide, or about 3.3 arc seconds per pixel. I then attached the camera to the telescope and saw that the planet was about 64 pixel wide, or about 0.56 arc seconds per pixel. This is more or less in line with the 1500mm focal length.

Since Jupiter was still somewhat "photographable" even with the cloud cover, I decided to take some more photos and stacked them to produce this nice result with all four Galilean satellites in view. The last time I took a photo like this was three years ago.

Telescope: Celestron NexStar 6SE
Device: Sony A5000 (prime focus)
Settings: (1500mm) - ISO 100 - 1/2s - (f/10)
Filters: None
Time: 2016-06-10 21:48 KST
Location: Naju, Korea
20 photos stacked with PIPP 2.5.6 and RegiStax 6.1.0.8