Tuesday, January 21, 2014

Jupiter's Moons

My father has a pair of binoculars which have fascinated me from my childhood days. If you look at the moon through that, you can see all mountains and valleys and craters. If you look at the full moon, you will have to look away because of its brightness. If you look at perfectly dark regions of the sky, you will find them full of stars that are invisible to the naked eye.

In spite of all its power, however, the binoculars did not make stars look like anything but points. Only when I looked at the brightest, unblinking stars could I see any noticeable increase in brightness or size. I learnt soon that these brightest stars were not stars at all, but they were planets of our solar system. As I grew up, I became really interested in astronomy through pre-dawn discussions with my grandfather sitting on the riverbank in Hooghly. In those days, the sky was much clearer in Hooghly and I even remember having seen the Milky Way, which I have been looking for ever since. Also, I had wonderful Russian books such as "Astronomy for Entertainment" and the book whose Bengali translation was called "টেলিস্কোপ কি বলে." This latter book was a true childhood favourite since it contained an imaginary trip through our solar system, stopping at the different planets or their moons and visualizing what we would see there. It was in this book that I  first read about the four largest moons of Jupiter - Io, Europa, Ganymede and Callisto. Around the same time, I realized that these four moons could be seen using my father's binoculars, and in the following years, I tried to see them whenever I got a chance.

The binoculars had one problem. Since they were quite heavy and had to be held by hand, my hands shook. This happens with everybody, and it can be reduced with practice. I believe my hands would now be steadier since I am used to holding a heavy camera these days, but at that time my hands shook wildly when I looked through the binoculars, and I found it difficult even to look steadily at the moon, let alone a small object like Jupiter. So while I got a glimpse of Jupiter's moons through those binoculars, I would have to wait many more years before getting a good look at them. Over the years, Jupiter remained my favourite object in the night sky. This was also probably because it was one of the very few objects that I recognized. In spite of all that love for looking at the night sky, I was never good at identifying stars. I can recognize some constellations like Ursa Major or Orion, and maybe the Pole Star. But I can recognize the planets Venus, Mars, Jupiter and Saturn when they are visible.

When my cousin bought a reflecting telescope last year, the first object that we saw after setting it up was Jupiter. This time I saw the moons quite clearly, but the telescope was large and difficult to point at anything in particular. I tried photographing Venus, Jupiter and Saturn from my Newark apartment but failed because of two reasons. Firstly very little sky was visible from that apartment and it was not possible to set up the tripod in such a way that I could point my camera at the planets. Secondly, Newark is full of lights and it is difficult to see too much in the sky, even after dark.

When I moved into this apartment in Virginia last November, I noticed two things: one, the apartment had a balcony, and two, there was a small wooded area in front of the building which meant the place was relatively dark. Naturally I was longing to take some pictures, but never got around to it until last week. On Saturday evening as I saw Jupiter rise over those woods, I set up my tripod on my balcony and took a few photos of Jupiter with all the zoom that I could muster. The windchill was -10 degrees Celsius, so I couldn't try too many different settings. Here's what I got.

Jupiter with its four largest moons.

Of course, my camera, lens and tripod may look like "heavy equipment" to laymen, but where astrophotography is concerned, my equipment is fairly amateurish. My camera sensor gets noisy at low light, my 70-300 mm lens when coupled with a 2x teleconverter generates a good deal of chromatic aberration and my tripod cannot completely prevent vibrations when this big lens is attached to the camera. So while taking this photo my equipment was operating at the very limit of its capability which means the photos are pretty bad. But even with the sensor noise, the lack of focus and distorted color, this is the best look I ever had at Jupiter's moons, and even this much was beyond my expectations.

Afterwards, I went out and tried photographing the night sky from the lawn in front of my apartment, and nearly got frostbitten fingers from the attempt. The photos were not very good, but the number of stars that I can see here are far greater than in Newark and I am hopeful that during the summer, I will be able to take some better shots of the night sky.

The eastern sky. The bright object near the bottom is Jupiter.