Category Archives: Planetary Occultations

It’s a ring!

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What a night this was – the evening that three Queenslanders discovered a ring around (50000) Quaoar and almost 18 months later on, today, at long last, the discovery was published in Nature magazine for the world to see!

Myself and many others were observing this event for a main body occultation predicted by Luckystar last year, but seeing that we were well out of the path we decided to take a long-shot and record early and late to see if we could discover anything unusual. And boy did that pay off

I was watching live with Renato Langersek and spotted a ‘blip’ several minutes early and jotted down the time in my observers log. The main event came and went as expected – a miss – but when we reduced the data it was clear that our data, and that of John Broughton, lined up perfectly.

And to quote John : “After downloading a Ser viewer I can confirm the occultation blip is for real! The only conclusion to come to is that Quaoar must have a narrow ring about 10km wide and by implication is indirect evidence of shepherd moons. The fact that only single occultations have been observed from 3 out of 7 sites suggest it’s a ring arc akin to those discovered in the 80s surrounding Neptune, but even those have non-opaque matter in the remainder of the orbit. With that in mind, and extrapolating the Queensland times southward, the NSW observers should look for a 1 or 2-second fade around 10:52:00 UT.”

And that my friends, is history.

Saturn Occulted

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After a few days build-up under superb skies here in Queensland, the big day comes and it clouds over! It is surprisingly rare that the moon passes in front of our solar system neighbours, so when it happens we get excited. These events are special in their beauty and rarity more than for any scientific value and 2014 has given us Australians three chances to watch Saturn disappear. This was the second and only partially successful for me as I recorded glimpses of the event through thick cloud.

Others have done much better and I’ll post some links as I get them!Saturn

Venus Occults Star

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Planetary occultations of naked eye stars have got to be one of the rarest celestial events. I had forgotten just how bad the ‘seeing’ was in my pre-dawn sky, but captured Lambda Aquarii emerging from the dark side of Venus this morning.

I’d been hoping to post a nice light curve of brightening as the star popped through the atmosphere, but the bad conditions made the video a little wild!

Very beautiful in its own way…

Eris casts its shadow over Samford

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It might not look much, but that light curve was caused by the most distant known object in the solar system, Eris, passing in front of an 18th magnitude star. It’s only the second event involving Eris ever recorded, the first had two observations made by professional observatories in Chile, and the first ever by an amateur.

Eris_close_up

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The event lasted for 60 seconds in the small hours of Friday the 30th of August and was made difficult by fog building up during the night making it harder and harder to see the target star! Fortunately there were enough photons hitting the camera to show what looks like a curved profile on the light curve that hints that Eris, like Pluto, has an atmosphere although previous observations didn’t give the impression of a curve and there are plenty of other less exotic explanations (such as low fidelity data!). We’ll just have to wait patiently until the next and hopefully brighter event when we can get much more data. One thing’s for sure: this observation will enormously help refine the known orbit of Eris, and make the next prediction even better!