Moon occults Saturn (2014 June 10)

posted: 1315 days ago, on Wednesday, 2014 Jun 11 at 15:03
tags: astronomy, astrophotography, occultation, Sir Brian, Moon, Saturn, Somerset West, Martin Lyons.

Last night's rare occultation of Saturn by the Moon was accompanied by Cnidarian 1 seeing conditions[1]. A subtle breeze kept the dew at bay for most of the time, and contributed only slightly to the 5C temperature. Since the occultation was predicted for around 19:15, "battle stations" was called just after 18:00.

With Sir Brian loaded in the car I uphilled it to Martin's house. While he, with a single finger, opened the roof of his observatory, I fumbled with tripod legs and bits-and-pieces. After just three aborted attempts Sir Brian was set up flawlessly. Slew Speed 9 felt like mere impulse engines so I loosened the RA and Dec and hand-slewed to the Moon. A 2-inch Antares 32-mm showed a jaw-dropping time-stopping view: the big beautiful white Moon chasing the exotic ringed yellow planet. Soul-food. Thankfully my reverie was interrupted - literally at the last minute - by a well-timed cell phone alarm, and I swopped eyepiece for camera. With the seeing what it was, focus was just about an optional exercise. Thank the gods for live view. Then it was over.

Meanwhile, around the corner in his snug observatory, Martin was broadcasting the occultation live on Night Skies Network (see images below).

Time for a coffee and a photo-shoot, and to get ready for the reappearance. Sky Safari Plus pinpointed where Saturn would appear, although I still don't know how to east-west flip the view. One-minute cell phone alarm, and we're off. It's never as exciting as a disappearance, but I suppose that's like choosing one Lindt over another.

Thanks to Martin for super-helpful tips on setting up a mount, to one or more engineers for live view, and to the Universe for arranging this special event.

[1] The Antoniadi Scale (Wikipedia article) is sometimes used by observers to characterize the seeing conditions (i.e. the stability of the atmosphere between object and objective). A more rarely-used metric is the Cnidarian Scale, which is a binary scale where a rating of 0 means "off-scale value; use the Antoniadi Scale instead", and a 1 means "like a jellyfish".

Richard Ford imaged the Moon soon after Saturn reappeared. (12-inch f/5 Dobsonian, 2X Barlow, Dobtorial tracking platform; EOS 1100D, ISO 200, 1/8th sec.)

(left) One of the two targets for this evening. (right) Sir Brian's view of things.

Saturn at the lunar edge. ISO 640, 1/500-sec, EOS 60D, 6-inch f/5.9 refractor.

Moon. The bright spot at top-left is the crater Aristarchus. ISO 320, 1/1000-sec, EOS 60D, 6-inch f/5.9 refractor.

Martin broadcasting live from his observatory.

nothing more to see. please move along.