Wesley's Tool-Box

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

This year's Perseids meteor shower was predicted to be prominent, garnering lots of public interest. Unfortunately for someone in Naju, the northern sky that the shower was to take place is polluted with light from Gwangju, making it hard to watch the fainter ones. To get a better view, I moved about 17km southwest to the Naju Bannam tumuli (ancient tomb mounds that encompass Sinchon-ri, Deoksan-ri, and Daean-ri tombs) next to the Naju National Museum. Upon arrival, I was disappointed to discover that the light pollution was still quite bad.

It was still better than being at home, so I set up my camera with the Deoksan-ri tombs #2 (left) and #3 (right) in front. There were already two families nearby who came to watch the sky. In the two hours I stayed, I was able to watch about five meteors falling, far less than the supposed maximum of 150 per hour. Of those, the camera caught two of them, the most striking one being shown here. The streak was going through the Andromeda constellation; the fuzzy dot to the left of the streak is the Andromeda Galaxy.

Meanwhile, the airplanes appeared much more often in the sky - there was one every five minutes or so. This is due to being more or less in the direct path of the flights between Seoul and Jeju, as well as Incheon and Southeast Asian cities. Even in this photo, the Mandarin Airlines flight AE231 (Incheon-Taipei) was caught on the left as a knotted line.

Device: Sony A5000 + SELP1650 (E PZ 16–50 mm F3.5–5.6 OSS)
Settings: 16mm - ISO 400 - 15s - f/3.5
Filters: None
Time: 2016-08-12 23:37:27 KST
Location: Naju, Korea

Earlier this year, I took photographs of the Orion Nebula, a.k.a. Messier 42, with the Canon SX50 HS camera or with Tamron 18-270mm lens attached to the Canon 450D. This was before I got my Celestron telescope, so I had high hopes of getting even better photos once the telescope was in my hands. Alas, the Orion constellation was already hiding below the horizon before midnight at this point, so I was focused in planetary targets most of the time.


As winter times creeped up again, the constellation was again viewable in the late night to early morning. That is, if the clouds, rain, or fog weren't obscuring it. This happened in the early hours of November 12, so I brought my telescope outside for a couple of hours of astrophotography. While I snapped several targets, the Orion Nebula looked the most promising.


As the conditions were good, I took the photos mostly without any filters. Then I took a few with the Baader Moon & Skyglow filter on to see what difference it might make. Once I started post-processing, I could see that the one with the filter might have a slight advantage in bringing out the faint details, but nothing dramatic. With the individual frames ready, I used the Deep Sky Stacker for the first time for automatic selection and stacking.

After about an hour of processing, the software selected five frames from non-filtered ones and one from the filtered ones to deliver this beautiful result. If you click on the photo for a wider, larger view, you can spot a part of the reflection nebula NGC1977 at the top left as well. In the future I may try to get this properly into the frame.

Telescope: Celestron NexStar 6SE + f/6.3 focal reducer
Device: Sony A5000 (prime focus)
Settings: (945mm) - ISO 1250 - 30s - (f/6.3)
Filters: None (5 photos) + Baader M&S (1 photo)
Time: 2015-11-12 00:51-01:14 KST
Location: Naju, Korea
6 photos stacked with Deep Sky Stacker 3.3.4

When I last looked at the comet C/2014 Q2 Lovejoy about three weeks ago, it was near its peak apparent brightness due to its proximity - it passed the closest to Earth just 3 days ago and shined at a magnitude of 4. The comet had now moved away, making its closest approach to the Sun two days before this observation. It was still relatively easy to capture it on the camera, as it's only dimmed back to magnitude 5.

The comet had moved to the constellation Andromeda. 59 Andromeda was below the comet, just outside the enlarged photo. The bright star directly above the comet in the enlarged photo is a magnitude 6.6 star called HR677 or HD 14272.

Some issues now complicate its observation other than the slow dimming. From where I observe, the western and northern sky is lit up with light pollution from the center of the city. And these days, constellation Andromeda is in the western sky, already starting to head toward the horizon after sunset. So I have to observe it in the early night, just when the area of the sky is not too brightened one way or another, at around 9 to 10 PM. The dimmest stars in this photo is around magnitude 12, so I think it was a success.

Device: Canon EOS 450D + Tamron 18-270mm Di II VC PZD
Settings: 432mm - ISO 400 - 30s - f/6.3
Filters: None
Time: 2015-02-01 22:29-22:39 KST
Location: Naju, Korea
8 photos stacked with RegiStax 6.1.0.8

Stars in the sky slowly move together in the sky due to the Earth's rotation. So the long exposure astrophotography involves using a star tracker to negate this motion. However, objects closer to Earth like the other planets tend to move slightly differently, and the change in position is noticeable over the course of a few days, as I've shown with the asteroids.

This movement is especially pronounced with the comet C/2014 Q2 Lovejoy these days, as it passed by Earth recently to approach the Sun. This 12-frame animation shows the comet moving through the sky over a 27-minute period, at an interval of roughly 2.5 minutes. These are from the images that were used to make the stacked image of the comet in my earlier post.

Device: Canon EOS 450D + Tamron 18-270mm Di II VC PZD
Settings: 432mm - ISO 800 - 30s - f/6.3
Filters: None
Time: 2015-01-10 21:39 KST (21:25-21:52)
Location: Naju, Korea

Since my last observation of the Comet C/2014 Q2 Lovejoy, I waited for the sky to clear up again so that I can try shooting with a star tracker (iOptron SkyTracker) installed. The opportunity came on the night of January 8. Annoyingly, all the attempts to take long exposure photos failed. I first thought the tracker may be faulty, but later I realized that the image stabilization on the camera lens was negating the tracker's movement.

I vowed to not make the same mistake again, and two days later, I went out to take photos of the comet once more. The southern sky was dark enough to let me barely see the comet with my naked eyes, so my hopes were up. And indeed, I finally got the results I wanted - much improved photos of the comet using the 30-second exposure (longest possible on Canon 450D other than bulb mode) setting. The green glow was now evident, and the center of the comet was shining brightly.

For the reference, the comet had moved to near the constellation of Taurus - the large version of the photo shows the magnitude 5 star 40 Tauri on the far upper left. Also, under the camera settings I used, the darkest stars were around magnitude 12, which is the most sensitive I've gotten out of my astrophotography attempts so far.


After taking the photos of the comet, I felt that it would be nice to point the camera at another object since the tracking setup was already in place. As the sky at my location was especially dark in the east and the south, I decided to take a look at the Orion Nebula inside the Orion constellation, which was in the east, going south.

Alas, due to being out for more than an hour in the below-freezing coldness, the infinity focus of the lens wasn't working quite right anymore and the fog on the lens was getting bad. So I took some measures to mitigate these issues somewhat and was able to salvage several shots before heading home. Luckily, those shots came out looking fine.

Device: Canon EOS 450D + Tamron 18-270mm Di II VC PZD
Settings: 432mm - ISO 800 - 30s - f/6.3
Filters: None
Location: Naju, Korea

[Comet]
Time: 2015-01-10 21:39 KST (21:25-21:52)
12 photos stacked with RegiStax 6.1.0.8

[Nebula]
Time: 2015-01-10 22:26 KST (22:07-22:31)
7 photos stacked with RegiStax 6.1.0.8