Friday, October 11, 2013

Large Binocular Telescope (Part 1)

Last weekend we got invited to tag along to the Large Binocular Telescope (LBT) employee family picnic day up on Mount Graham!  The above link is great because it includes a time-lapse from a year ago when the Russian kids were visiting and we got to see the dome opening, as well as some other links to various aspects of the Observatory...  The telescope is made up of 2 large mirrors, each 8.4 meters (a little under 30 feet diameter), that for some instruments work together, and others work separately.  Since I was supervising the crew that polished the mirrors, I literally can't get enough of this telescope, and thankfully, Melinda agrees with me!  It is literally like visiting a technological cathedral, both in size and scope, and sitting atop a 10,700 foot mountain, is a very special place!  At left is the LBT building just before sunset in normal visible light color, and at right is the view from 150 meters down the access road in infrared light.  It is constructed from 3 exposures of different lengths because of the extreme variations in light from the overexposed dome to the tree shadows - so had to take an HDR (high dynamic range) exposure.

And while I think that my polishing the mirrors
was enough to get me into the annual picnic, we actually got to go because my friend Lee works there now, and we got to tag along with him and his family to the potluck affair.  Lee's wife Michelle cooked fried chicken and baklava, and we offered to drive everyone in Min's Jeep.  It was a beautiful day and while warm down in the desert, it was nice and cool atop Mount Graham.  The "dining hall" where the astronomers relax and enjoy down time while observing was fortunately large enough for the 40 or so attendees.  Some of us spilled out onto the deck to enjoy the view, which is where I took these IR pictures.  At left is the view to the west towards the Vatican Advanced Technology Telescope (VATT) in the small dome partially behind the trees, and the Sub-Millimeter Telescope with the open doors at right.  While the fir-spruce forest here at nearly 11,000 feet elevation doesn't have the brilliant white of deciduous leaves, they still look light in tone against the dark sky in these IR shots.  At right the edge of the forest is seen, with the yellow rope defining the limit of human trespass - because of the scarcity of the red squirrel population, we are definitely prohibited from roaming through the woods!

After stuffing my plate (and myself), I went out in search of pictures, where I got the above and some in the telescope enclosure as well.  While I packed some ultra-wide lenses, there is some satisfaction in retaining the resolution of some large mosaics as well, so I shot some of those too.  The picture at left is a mosaic of 6 frames that was taken below one of the telescopes.  Because the mirror towers over me, there is some distortion, but many details of the scope can be discerned.  This one was taken early on and shows the tertiary mirror still deployed near the mirror center.  Shortly after this was taken, it was removed from the optical path.  The elevation bearing (hydrostatic - rides on a microscopic layer of oil) is the arc of steel at left, and the duct work at right vents air from the mirror and telescope out of the building.  The picture at right was taken a little later once the telescope was open.  It is a 3-frame mosaic taken from behind and near the same level as the same mirror shown above.  Here you can see the tertiary mirror is pulled out (below), and the blue prime focus camera is installed above.  The steep curve of the F/1.14 primary mirror can be seen - and they are deep!  It doesn't look it, but they are over 18" deep in the center!  In this shot also, you can see when the Gregorian secondary  and flat tertiary mirrors ARE installed, it can feed any one of a number of instruments that can be seen through the apertures at the right of the mirror.  Lee was telling me which instrument was which, but he came back later saying he had been confused, so now I'm really confused and won't claim I know which any of them are except the CCD prime camera that is top center!

Right about sunset the telescope operator rotated the dome 360 degrees and we were treated to a leisurely panorama of the entire horizon!  Some of the highlights was Heliograph Peak a few miles to the southeast, imaged at left.  Named for the heliograph station located on the peak in the 1880s, it used mirrors to flash signals using sunlight over great distances during the campaign against Geronimo's Apache tribe.  It now consists of an array of various transmitters.  You can see the effects of the big fire that in 2004 came within a kilometer (1/2 mile) of the LBT observatory.  You can also see a flash of yellow foliage from the aspen trees that have been established since the fire.  And while it wasn't being used for observing that night, over our heads in the growing darkness was the Gregorian secondary mirror, reflecting parts of the interior of the telescope structure. 

We finally got kicked out of the telescope enclosure, and while the girls warmed up a bit before the drive down the mountain road in the dark, I stepped out on the deck to take a few more twilight shots.  Visible far to the southwest on the far side of the Tucson valley was, of course, Kitt Peak and Baboquivari.  Kitt Peak is about 40 air miles SW of Tucson, LBT is about 80 miles NE, so Kitt Peak is close to 120 miles, but still line-of-sight from Mount Graham, though barely visible past the Catalina Mountains that are north of Tucson.  At left is a 3-frame mosaic with the 200mm zoom showing Baboquivari to the left, Mount Lemmon to the right.  Kitt Peak is the flat-topped mountain on the down slope of the Catalinas at right.  The picture at right shows a close-up of Kitt Peak, with the telescopes barely resolved a few minutes later deeper in twilight.

We survived the 3-hour drive back to Tucson just fine.  Michelle wasn't sure she wanted to go back to Graham anytime soon, but Min and I are ready any time - it is such a special place to spend an afternoon or evening.  Perhaps sometime I'll get to stay late at night!  Part 2 coming up, hopefully I'll figure out how to post my videos!

1 comment:

Astroweis said...

Fantastic, Melinda and Dean!
Quite unthinkable here to see something that is 120 miles distant.

I observed from a turnout on the way up to Mt Graham shortkly before the dirt road starts and I was delighted to see the milky way even though the moon was close to it. What wonderful places you guys have in AZ!