Thanks to the fine carpenters at the Academy, we now have our Sloan Digital Sky Survey (SDSS) plate mounted and hanging on my classroom wall. It has been encased in a wooden box filled with ornamental lights, giving it that astronomical view.

The SDSS Plate in its display case. Note the markings which help astronomers identify the various targets.

Information on the plate itself is rather interesting. This is a plate for the Baryon Oscillation Spectroscopic Survey (BOSS) which has the goal of mapping baryon acoustic oscillations signatures by looking at the spectra of some 1.5 million luminous red galaxies. The survey will help astronomers to place limits on the universe’s expansion rate, and more! The plate here was used to hold optical fibers on the SDSS telescope’s focal plane so that each fiber, attached to a hole on the plate, captures light from just one galaxy. That light is then funneled down the fiber optic path to a spectrograph.

The plate has a bunch of markings on it to help astronomers with the data collection process. Fiber optic bundles are grouped together such than each bundle gets a section of the plate bounded by a black border. Blue circles around the openings correspond to the galaxies locations for which spectra are being collected. The black circles around the holes correspond to guide star locations in the field.

The SDSS plate illuminated.

This is the SDSS field of view for this specific plate. Click on this image to go to the SDSS Navigate tool and have a look around!

SDSS BOSS Plate 6192/56269
Observed on MJD 56269 (8-December-2012)
Plate center: RA = 7.98654794692993, dec = 16.3795967102051
SDSS BOSS Plate 6192
SDSS BOSS Plate 6192’s field of view as seen by the SDSS
The SDSS then converts all the spectra to plots and measures their z (redshift) values, among other things. One spectra from the many on this plate is below

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Students and community members joined the crowd at the observatory on Friday night (10 February) to enjoy the penumbral lunar eclipse that was gracing our skies that evening. The moon made its way above the trees in the east by 6:15pm, a lovely full moon, so bright that it looked like floodlights had illuminated the soccer fields by the observatory. It was cold!  The thermometer hovered at 11°F and the wind was calm. As people gathered, there was a pulsing of people headed into the Chart House to stay warm, along with those coming back out to view the eclipse’s progress.

This was our first almost-clear evening in quite a while. The day before was the first “snow day” that the Academy had enjoyed in a long time! The new snowfall, well over 10″ deep, had ben plowed from the paths (THANK YOU to our facilities department!), allowing access to the Chart House and Kurtz Dome housing our 16″ SCT telescope. We also had a camera with zoom lens attached, and a pair of tripod-mounted binoculars for people to enjoy.

As predicted, clouds did start rolling in by 7:30pm. With the eclipse hitting maximum at 7:44pm, we had a good view of it before all was obscured. Two good photos below: One of the moon at maximum eclipse, and one of the moonlight causing a 22° ice halo and moondog. Both taken with a D810a and 300mm lens.