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Here Comes Jupiter

It takes Jupiter about twelve years to orbit the Sun just once. We, here on Earth, are of course closer to the Sun and go around much faster—once per year. So, every 13 months we “lap” Jupiter. The next lapping event, which astronomers call “opposition”, will be on October 29th of this year. On that...

It takes Jupiter about twelve years to orbit the Sun just once. We, here on Earth, are of course closer to the Sun and go around much faster—once per year. So, every 13 months we “lap” Jupiter. The next lapping event, which astronomers call “opposition”, will be on October 29th of this year. On that night, Jupiter will be in prime viewing position high in the sky around midnight. Between now and then, Jupiter is best viewed after midnight. In fact, it is currently in good position for viewing just before sunrise. If you are a morning person like me, this is perfect.

In fact, early morning observation of planets is often better than evening observing because there is usually turbulence in the atmosphere for a few hours just after sunset as the ambient temperature drops rapidly. But, in the early morning, before sunrise, the air is often at its most stable.  Having stable air is critical for observing Jupiter, and the other showcase planets, since these objects, while bright, are very small and require plenty of magnification.

To help me plan for observing, I subscribe to an email service provided by Mark Casazza called the Clear Sky Alarm Clock. This service accesses the Clear Sky Charts produced by Attilla Danko based on forecasts from the Canadian Meteorological Center. Marc’s server knows my geographical location and whenever the forecast looks good for astronomy in my neighborhood I get an email alerting me to that fact. These forecasts, available to amateur astronomers throughout North and Central America, have proven over the years to be amazingly accurate and are widely used.

Anyway, I received an email alert on August 23 that the observing conditions where I live in New Jersey were expected to be “good” all night from sunset on the 23rd to sunrise on the 24th. I decided to use this opportunity to take a picture of Jupiter with my 10 inch reflector telescope (from RC Optical Systems). I got up about 3am. My telescope is permanently attached to a German equatorial mount, which sits on a tripod that in turn sits on a set of wheels allowing me to quickly and easily roll the whole contraption out of my garage and onto my driveway. I was dressed and everything was rolled out by about 3:30am.


Rolling out the equipment (in the daytime)
Rolling out the equipment (in the daytime)

After the roll-out, the next important thing to do is to make sure that my telescope is cooled down to the same temperate as the air. If not, then the telescope itself will generate air turbulence that will mess up the view. My telescope has fans that draw air over the mirror to facilitate a quick cool down. I set these fans at maximum power for about 30 minutes after which the telescope was basically the same temperature as the surrounding air.

While the telescope was cooling down, I worked to get my camera set up. I decided to use my Canon XSi DSLR camera because there is a third-party software program, EOS Camera Movie Record, that allows me to grab full-resolution real-time video from my camera directly to my computer.

Between the camera and the telescope I inserted a special lens, called a Barlow lens, that further magnifies the image. Barlow lenses are pretty important when imaging Jupiter and the other planets as these are small objects that require as much magnification as possible.

All together, I took 15 separate short videos most of them one or two minutes in duration. After putting everything away and grabbing another hour or two of sleep, I reviewed the videos and selected what appeared to be the best one for further processing. Here’s a short segment from the one I chose…

Short video of Jupiter taken with DSLR on 10″ reflecting telescope.

I used a program called Registax to assemble the video frames into a single picture of Jupiter. Here’s the stacked image…

Jupiter before sharpening
Jupiter before sharpening

To get from this blurry image to the nice sharp final image shown at the top, I used something in Registax called “wavelet sharpening”. This sharpening tool is really amazing as you can see.

Anyway, note that the Great Red Spot, which is not red anymore, is rolling into view in the lower left part of Jupiter. The Great Red Spot is a storm on Jupiter that is about the size of Earth itself. This storm makes Hurricane Irene seem small by comparison. But, of course, not many people live in the path of the Great Red Spot.

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Meet the Author

Robert J. Vanderbei is chair of the Operations Research and Financial Engineering department at Princeton University and co-author of the National Geographic book Sizing Up the Universe. Vanderbei has been an astrophotographer since 1999, and he regularly posts new images on his astro gallery website.