Seeing Jupiter from Herstmonceux

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THIS FASCINATING photograph of the plant Jupiter was taken by an amatuer astronomer at Herstmonceux Observatory and Science Centre.

Richie Jarvis, of South Chailey, an IT ‘guru’ by day who studies the stars at night, is passionate about taking deep-sky images – ‘stuff outside our solar system’, he explained.

He snapped this image during an open evening at the observatory where he is a volunteer, at the end of October.

Mr Jarvis said: “Taking pictures of the night sky is always challenging - I’ve been learning for the last 10 years, and am still continuing.

“Deep-sky images are taken using very long exposures, whereas planetary images are taken using the shortest possible images.”

Deep-sky objects are very dim but planets are very bright, he said.

Mr Jarvis added: “When we look at stars or planets in the night sky, we are looking through a turbulent atmosphere.

“Astronomers call the stability of the atmosphere ‘seeing’ - the better the ‘seeing’ the more stable it is, and the better the view you get.

“You can see this effect easily in the night sky - that is why the stars appear to flicker.”

The image shows Io (Jupiters closest moon) passing in front of the planet, leaving a shadow.

The Great Red Spot is also clearly seen – a storm which has been raging for more than 181 years, according to Mr Jarvis. And two ‘barges’ which are also fierce storms, ‘larger than Earth’, he added.

Both the north and south equatorial belts can also be seen.

The image was captured during one of the many open evenings held at the observatory.

Mr Jarvis said: “I thought I would try putting my planetary camera onto [the Observatory’s] 16” scope.

“This image was one of the results - the first time I’ve managed to get a decent planetary image.

“I also managed to get enough data for a short movie showing the end of Io’s transit as well - its on my blog (http://nebul.ae/blog.html).”

Mr Jarvis added: “That night, I had the pleasure of showing an ever-lengthening queue in Dome C the wonderful sight of Jupiter, with Io transiting the disk.

“The instrument was a Meade 16” telescope (3 metre focal length) which the Observatory owns.

“After the open evening, myself and a few other volunteers stayed on for an hour whilst the images were taken with my planetary camera.

“I shot 60 seconds of images, which equated to about 1800 frames - the image shown was the best 593 frames.

“I shot about an hours worth that night all-in-all - which came out at 27GB of data in the end.”

The trick with planetary imaging was to take the ‘shortest possible exposures you can’, Mr Jarvis said.

He added: “Throw any which are blurred because of atmospheric turbulence away.

“You then stack all the good ones together with a bit of free software called ‘Registax’, and then run some special sharpening tools called ‘wavelets’ in Registax.

“It works because the stack of the frames is better quality than just a single image - everything which is in the ‘same’ place on each image adds together - anything which is only present in a single image can be discarded by the software.”

Future open evenings will be held at the observatory from 6.30pm to 11pm on November 11, 19 and December 3. See www.the-observatory.org