Unlike a big bright Moon on a clear night, it is difficult to capture a decent image of Saturn through a mobile phone. Most of the time, all you will see is an over-exposed featureless ball with a featureless over-exposed bright ring around it. And that is provided you have enough patience and good hand-eye coordination to hold your phone camera still and at the exact spot over the eyepiece of the telescope.
But still, some are just happy that I managed to help them to capture some sort of ring structure surrounding a ball in their phone. Especially after seeing Saturn live through the telescope for the first time.
Personally, I have given up trying to shoot Saturn with my mobile phone after a few attempts through 5-inch/6-inch telescopes without tracking. The usual result, a small bright over-exposed image, is not worth my time. I rather spend those time observing Saturn live.
But a recent acquisition of a bigger aperture telescope, a 10-inch dobsonian, made me curious enough to give it a try again. Still, there were some doubts if the image will turn out well. There is no tracking on my dobsonian telescope. At high magnification, it drifts very quickly across the field of view. At lower magnification, the image scale of Saturn may be too small and risk being over-exposed again.
Saturn opposition in late April 2013 is a great opportunity. So during the public stargazing session on eve of Labour Day at Bishan Park, I decided to give it a serious try after most of the crowd was gone.
Decided to put my patience and hand-eye coordination to the test and go for high magnification at about 312.5x (20mm eyepiece + 5x tele-extender on a telescope with 1250mm focal length). Set my HTC One S exposure value to -2, ISO 100 and fired off about 3 shots the moment I see Saturn appearing on the phone screen.
Reviewing the shots at 100% size on my phone, the last shot seems decent though small. This was how small Saturn looked like in the 3264 x 1840 pixel image:
Using my fingers to zoom in on Saturn, I was expecting the same old featureless, over or under-exposed or low signal-to-noise image ... ....
OH MY GOD !!!!!!!!!!!!!!!!!!!!
I couldn't believe my eyes! Is that thin black gap in the middle of the ring the Cassini division? Are those really bands of the planet? Did my phone really captured this image? After recovering from the shock, I quickly showed it to my astro buddies at the park and twittered the image.
This is final image after some minor photoshop touch-up to bring up the contrast.
This image is way better than my first planetary imaging attempt a few years ago with my 5-inch Maksutov-Cassegrain telescope!
So glad I challenged my own assumptions about what can be captured via afocal astrophotography with a handheld mobile phone through a sub-$2000 amateur-size non-premium telescope on a non-tracking mount.
Now I can't wait for the next Jupiter Opposition!!