Wesley's Tool-Box

In the early evening these days, Saturn is seen shining brightly in the southwestern sky. The apartments nearby hinder the sight well before it sets into the western horizon, though. And in a few weeks, even this narrow opportunity would go away. This meant that now was the time to take photos of Saturn with my new A5000.

Preliminary attempts last week were disappointing, however. The planet looked dark and fuzzy. After analyzing the problem, I concluded that the rails on the window and the pollution (atmospheric and light-induced) near the horizon were causing this. So I raised the telescope up a bit and tried to shoot as early in the evening as possible.

As a result, the photographs from last evening came out looking good. Cassini division and the differently-coloured layers of the surface are all visible. This is comparable to the ones I took back in May, even though the apparent size is smaller (18.32 vs. 15.85 arc seconds). This may have been helped by A5000 having a slightly higher resolving power (0.19 vs. 0.20 arc seconds / pixel) than iPhone 6 Plus.

This is encouraging in a couple of ways. This confirmed A5000's ability to provide almost all my astrophotography needs. And on May 2016, Mars will be about as big as Saturn today (excluding the ring part), so I may be able to get some nice photos of the red planet.

Telescope: Celestron NexStar 6SE + 2.5x barlow
Device: Sony A5000 (prime focus)
Settings: (3750mm) - ISO 800 - 1/4s - (f/25)
Filters: None
Time: 2015-09-22 19:35 - 19:44 KST
Location: Naju, Korea
33 photos stacked with RegiStax 6.1.0.8

Not content to just photograph planets, I tried my luck at catching glimpse of some of the Messier objects that came into the southern view. After trying various high ISO settings, it seemed that ISO 3200 is as far as I could push my A5000 for where I live before too much details were lost. And under this setting, Messier 2 and 11 came out looking fairly well.


Messier 2 is a globular cluster, as it is a group of stars that are tightly bound together in a bright round ('globe') shape. Meanwhile, Messier 11 (Wild Duck Cluster) is an open cluster, a more loosely packed group of stars that still stand out from the background. They seem to be very good examples for A5000 to shoot for their respective category. I've taken photos of several other Messier objects that are star clusters, but these looked the best.

Telescope: Celestron NexStar 6SE
Device: Sony A5000 (prime focus)
Settings: (1500mm) - ISO 3200 - 30s - (f/10)
Filters: None
Location: Naju, Korea

M2: 2015-09-19 23:08 - 09-20 00:14 KST (2 photos stacked)
M11: 2015-09-19 21:20-21:38 KST (2 photos stacked)

As Pluto moved toward the western horizon, a planet started to come into the telescope's view through the southern window - Neptune. It was the first time I had seen it in person, but seeing as how relatively dim it is compared to other planets (magnitude 7.8), I decided to take photos the same way I do for stars.

Sure enough, it was caught on the photos as a moving bright spot, next to a 6.9-magnitude star called HD 214686. But I soon discovered that it wasn't the only object moving. A faint dot of about magnitude 13 was moving considerably faster than Neptune. Given the brightness, it had to be a small but known celestial object.

Consulting the minor planet database revealed the object to be 303 Josephina, an asteroid from the main belt with a diameter of about 100km. Out of pure coincidence, I had caught a planet and an asteroid together on several photos.


But the surprise didn't end there for me. I noticed that Neptune either had a bump or a small dot next to it. It turned out that it was Triton, by far the largest satellite of Neptune with apparent brightness of magnitude 13.5. Photographs taken a day apart clearly shows its changing position relative to the planet, as well. So thanks to the long exposure photography, I was able to take a planet, a satellite, and an asteroid all at once.

Here's the full version of the final frame of the animation, if you want to see it.

Telescope: Celestron NexStar 6SE
Device: Sony A5000 (prime focus)
Settings: (1500mm) - (f/10)
Filters: None
Location: Naju, Korea

#1: ISO 800 - 20s - 2015-09-10 00:14 KST
#2: ISO 800 - 20s - 2015-09-10 01:12 KST
#3: ISO 800 - 20s - 2015-09-10 02:34 KST
#4: ISO 1000 - 30s - 2015-09-10 23:28 - 23:30 KST (3 photos stacked)
#4: ISO 1000 - 30s - 2015-09-11 00:32 - 00:37 KST (2 photos stacked)

One of the main reasons I decided to buy a new camera was that it would yield a lower-noise photo at high ISO settings, making it better for long-exposure astrophotography. To confirm this, one of the first objects I chose to take photos of was the dwarf planet Pluto.

It moved a little to the east since the last time, already past the ξ2(Xi 2) Sagittarii and not near a particularly bright star. The brightest stars in the animated frames above are only about magnitude 11. Nevertheless, Pluto was discernible when comparing the two frames taken a day apart under a bright monitor. Dimmest stars visible reached magnitude 15, and Pluto itself moved clearly enough to see that it's not a background star.

If you feel particularly bored, you can try picking it out of the full version of the September 10 photo.

Telescope: Celestron NexStar 6SE
Device: Sony A5000 (prime focus)
Settings: (1500mm) - (f/10)
Filters: None
Location: Naju, Korea

#1: ISO 800 - 20s - 2015-09-09 22:09 KST
#2: ISO 1000 - 30s - 2015-09-10 21:44 KST

My Canon EOS 450D DSLR camera is a fine equipment, but it is showing its age. So I decided to invest in a new equipment but not at too much expense. After much comparing, I decided to go with A5000, an entry-level mirrorless camera from Sony. It's got a highly sensitive sensor for its class, yet it's currently selling at quite a discount - about US$280 with a 16-50mm bundled lens, or just under US$200 for the main body.

As I ordered this camera, I also bought a T-ring for its E-mount lens mount so I could install it on my Celestron telescope. What you see above is how the camera looks with this attachment. I only took a handful of photos with the bundled lens before replacing it with the T-ring to start photographing the stars. I'm keeping the lens around just in case I need to shoot regular photos.


And this is how my new astrophotography setup looks like. The camera is practically the lightest APS-C sensor-based mirrorless camera out there, so it hardly burdens the telescope. I can also use my smartphone to remotely control the camera - a convenient feature that also prevents shaky images. I'm hoping to get some nice photographs out of this, so stay tuned.