Sunday, February 14, 2016

Mining the Archives!

We've not been out of the house much the last week other than visits to the oral surgeon and cancer center, which generally make for boring posts, so have been reviewing some of the photo archives to see potential post material I've missed lately. So not really timely, but this one is recent...

Just 2 months ago (13 December), on my way back from watching the sunset behind Kitt Peak from the Mount Lemmon Highway, I paused at Babad Do'ag ("Bad Dog" as I sometimes refer to it) as I frequently do. About 3 miles up the road to Mount Lemmon, it has a great parking lot and overlook with a spectacular views of the Tucson Valley and beyond. It is where I've shot images like at left with Kitt Peak in the far distance in silhouette behind the lights of metropolitan Tucson.

But there are other targets, including other observatories! To the south across the Tucson Valley are the Santa Rita Mountains, with Mount Wrightson as the highest peak on the left at about 9,500 feet. Mount Hopkins, about 1,000 feet lower at 8,500 feet right in the center of the frame at left is the home of the Multiple Mirror Telescope (MMT). Originally so-named because its innovative design combined the light-gathering power of 6 individual smaller mirrors each 1.8 meters (72") diameter, now consists of a single primary mirror 6.5 meters (256") diameter. I've got a connection to it as it was the first large mirror over 3.5 meters I polished the Mirror Lab where I work. A before-and-after image of the telescope from the website above is shown at right. People ask why it is still referred to as the MMT - my thought is that most large telescopes consist of primary and secondary mirrors to get the lights to the instruments, so "multiple" still applies!

Both of the above photos were taken on 13 December with my 200mm lens - the Kitt Peak shot a panorama put together from several images at 200mm focal length. The Santa Rita's shot was a single-shot taken with the same lens set to 110mm. Mount Hopkins at about 40 miles distance, is a little closer than Kitt Peak's 54 miles from "Bad Dog". At left here is a panorama put together from 8 images taken with the Meade 80mm F/6 APO (480mm focal length). Shown at the Blog's 1600 pixel limit, you can spot the squat building of the MMT atop Mount Hopkins at right center. At left is the frame showing the MMT at nearly full-resolution. Not a lot of details can be spotted compared to distant views of Kitt Peak, but you can see how the conical mountain profile would provide smooth laminar airflow over the peak, which is supposed to provide excellent seeing at MMT. There are actually a number of smaller scopes making up Fred Lawrence Whipple Observatory near the peak at Hopkins, but they aren't visible here, since they are located on the south side on a saddle below the peak.

Finally, before leaving "Bad Dog" that evening, I took another set of images with the Meade scope in full darkness to see if I could still capture the mountain profile. Sure enough, with 30 second exposures, it can be spotted, since the profile is backlit by the light glow from Nogales, AZ another 30 miles to its south. The bright lights are either from the drag strip or the Pima County Fairgrounds near Houghton south of Interstate 10, about 20 miles away (halfway to MMT!).  Interestingly there are no star trails visible, though there is a lot of extinction that close to the horizon...  Even 30 seconds at F/6 failed to catch any. 

This is the second post mentioning MMT or Mount Hopkins. The last was from 2009 (!) when Melinda and I took part in a star party for the public at the base camp at the base of the mountain. I've not been up to MMT in over a dozen years - might be fun to take it in again since going digital!

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