Wesley's Tool-Box

Sun is measured to be the most perfectly round sphere occurring in nature. But as the Sun sets over the horizon, it looks more "squished" than usual due to atmospheric refraction. This photo was taken when the Sun's altitude was merely 3.27 degrees.

You can still see the sunspots just fine - AR11960 (top; "sunspot 1960") and AR11959 (bottom; "sunspot 1959") are visible at the lower area. The light blemish at the lower right edge is the AR11957.

Device: Canon SX50 HS
Settings: 1200mm - ISO 80 - 1/40s - f/6.5
Filters: Baader AstroSolar Safety Film
Time: 2014-01-26 17:25 KST
Location: Suwon, Korea
79 photos stacked with RegiStax 6.1.0.8

I've been using my Canon SX50 HS superzoom camera almost exclusively as an astrophotography machine since middle of last year. The 50x zoom is enough to make many of the planets show up as disks rather than spots, so it feels like having a compact telescope with integrated camera. At full zoom, the settings are at 1200mm, f/6.5, and ISO is set to 80 for best quality. Jupiter shots are usually taken at around 1/100 to 1/250s shutter speed (it was 1/160s here), while bright Venus shots can go up to 1/1000s.

Of course, even such massive zoom by camera standards don't make the planetary disk very big. two biggest examples are Jupiter, which goes up to about 32 pixels wide, and Venus, about 41 pixels wide. So getting good details from a single shot is difficult. I have to apply some techniques used by the astrophotography community to enhance the results.

The big helper is undoubtedly RegiStax, which does both stacking and wavelet processing. The stacking averages the multiple photos of the same object, which preserves the details while reducing noise. RegiStax doesn't simply stack the photos, though. They are aligned and only the ones with good quality are picked out for stacking, which improves the quality even further.

In this Jupiter example, I took 131 photos of the planet, out of which 41 of them were picked by RegiStax for stacking. Compared to the grainy photos originally taken by the camera, the stacked image is much more cleaner and smoother. But the cloud features are soft and hard to make out. This is where wavelet processing comes in.

Wavelet processing can be used to amplify the little details in the photos and make them stand out. After making some adjustments on the strength of each wavelet layers, the cloud features became more distinct. There's a ripple in the lower part, and magnifying the processed photo by 200% shows that this is the Great Red Spot (GRS). Rotating the photo (by 54 degrees in this case) makes the planet look "upright".

And this is how I currently process the planetary photos.

Settings: 1200mm - ISO 80 - 1/160s - f/6.5
Time: 2014-01-19 02:57 KST
Location: Suwon, Korea

Here is all my recent observations of Venus through Canon SX50 HS in one picture. I think it shows pretty well how Venus dramatically approaches Earth while being in the inner orbit. The last six observations have been posted in the blog before:

[2013-10-30] [2013-11-17] [2013-11-30]
[2013-12-07] [2013-12-21] [2014-01-04]

The first two didn't look much on their own, so I didn't make an entry about them when they were photographed, but they make for a nice comparison, so I included them here now.

Venus will be closest to the Earth on January 11. Since it's on an inner orbit, it'll be aligned very close to the Sun. So it'll set almost simultaneously with it, making it hard to see this week or the next.

This photo I took over the weekend is the one last good look at the planet before it shows up in the morning instead of evening. It's gotten quite big and was still relatively bright against the dusk.

Device: Canon SX50 HS
Settings: 1200mm (2x enlarged) - ISO 160 - 1/10s - f/4.5
Time: 2014-01-04 18:02 KST
Location: Suwon, Korea
55 photos stacked with RegiStax 6.1.0.8

As Venus comes closer, the crescent shape keeps growing bigger, and effectively negates the thinning. I guess that's why the planet still shines bright in the evening sky.

Settings: Canon SX50 HS - 1200mm (2x enlarged) - ISO 80 - 1/250s - f/6.5
Filters: None
Time: 2013-12-21 18:04 KST
Location: Suwon, Korea
32 photos stacked with RegiStax 6.1.0.8