Tuesday, 14 October 2008

Hawaiian sky at night

It's an awful night tonight: thick cirrus + full moon = no science and likely no discoveries. The summit tourists and astronomers would have been treated to a spectacular sunset though.

The summit of Mauna Kea must have one of the densest populations of webcams on the planet. I'm sure there are other places that rival it but in the last year or so the number of webcams has increased enormously. So has the number that can now provide images at night as well as during the day. The images (and movies) are all available from a Mauna Kea Weather Center (MKWC) page.

Tonight the halo around the moon is clearly visible and that's always a bad sign for astronomers. Ice crystals in the upper-tropospheric cirrus clouds are refracting light from the moon into a beautiful ring - I can't measure it from the webcam image but it should have a radius of 22 degrees otherwise something is wrong with the atmosphere's physics tonight. It means, however, the sky isn't clear so observations of faint stars and galaxies aren't on for tonight.

The image above is from the CFHT's webcam facing towards the north-north-east. The one below is again from the CFHT, this time facing south, towards Mauna Loa. The telescopes you can see, from left to right, are Gemini North, the UH 88-inch and the UKIRT. It looks as though the slits are open and the telescopes are looking at something, but there will be a bunch of frustrated scientists inside those domes tonight.

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