Right Place, Right Time!

Am currently in the Midwest and enjoying Fall temperatures at "Ketelsen East" as the highs struggle to reach 70. It is near perfect for going outside and doing fun stuff like biking and exploring. I heard from my astronomy connections at Adler Planetarium last week that they were going to remove the 20" Doane Telescope mirror for some work, and I offered my assistance since I have a little knowledge about handling large optics. It was gladly accepted! The Adler Planetarium dome is shown at left with the massive expansion behind, and at right is the funky striking dome of the Lakeside Doane 20" telescope at right.

While there, Chicago Astronomical Society president Tony Harris sidled up to me and asked what I was doing the next night... Well, he had pulled in a favor and had a personal tour scheduled at the LARGEST REFRACTOR (lens) TELESCOPE IN THE WORLD (40" diameter), at Yerkes Observatory about 90 minutes NW of Chicago the next night! And he had invited me along on his 3-person tour!


So the next day after a little afternoon nap
to prepare for the potential all-nighter, I took a post-dinner drive up to meet Tony and Larry at a convenient place along I-90 on the route to Williams Bay a little over the Wisconsin border on the west side of Lake Geneva. While there was an early evening public program going on, we were to show up at Midnight to meet our tour guide Chuck. We were fashionably early and as we walked up to the door at 11:45, he greeted us at the door!

Ironically, the 40" telescope and the entire Yerkes Observatory, established in 1897 is about to be closed as the owner, the University of Chicago defunds the institution. While they rightfully claims that no scientific research has been going on there in recent years, it has been popular in the realm of outreach and public education, and for some spectacular visual observing like we were looking forward to.



Walking into the dome always impresses! I've visited a couple times, but the huge dome and floor (that rises and lowers over 20 feet to get observers to the eyepiece) is just shockingly large! Once the lights were out and dark adapted, it was easy for me to move about with my camera and tripod to take a few shots. Unfortunately it was a nearly full moon, which brightened the sky affecting some views, as well as a few thin clouds drifting through doing the same. The most impressive views (at 350X!) were globular cluster Messier 15, as well as NGC 7662, the "Blue Snowball" planetary nebula. Neptune easily showed its disk as well as its large moon Triton, but a couple other objects did not show well with the bright sky and cirrus. Finally we moved to the moon itself and enjoyed some viewing and tracking along the terminator.  At left with the diagonal and eyepiece removed, Tony looks up the tube at the real image formed by the giant lens. At left is the more traditional view with the eyepiece providing about 350 power...


About this time we were joined by a few students from U of Chicago who had been hosting groups in other parts of the Observatory (shown at left). With the lateness of the hour and Orion still out of reach to the east, it appeared the moon would close out our observing. But before that, both Tony and I were permitted to mount our cameras on the telescope for a few shots! It isn't often you get a chance to use a 19,000mm telephoto lens!

Achromatic objectives, even mighty classical ones like this one, suffer from chromatic aberration, where green, red and blue wavelengths are not perfectly focused to the same point. It is most noticeable on bright objects like the moon, and mostly not objectionable on most objects. In any case, Tony had mounted a yellow filter to block out some of the unfocused blue light, but in my shot at right, I took out the color to make this 2-frame mosaic of the Mare Crisium (Sea of Crises) part of the Moon's terminator...

As the observing wound down, we took a selfie of the 4 of us - that is the 4 of us at left, Dean (me) at left, Larry, Tony and Chuck. The moon, of course, is the bright object, and the constellation Aries appears at the top of the dome slit. This exposure, and all of the Yerkes photos save the moon shot, were taken with a Sigma 15mm fisheye with the Canon 6D. It was easy to shoot inside the dome, yet be able to capture the entire refractor in one shot...

Before he escorted us downstairs to the historical offices and some cool displays, Chuck took us out on the catwalk to enjoy a bird's eye view of the Observatory grounds and surrounding territory. Lake Geneva was visible in the moonlight to the south, but in this view towards the easy, the other domes housing a 40" and 24" reflecting telescopes are visible with Orion rising high into the sky on the right side. The 40" dome shutter assembly is visible at upper left. This is a 4-second exposure at F/4...


After a brief walk-thru showing us some of the historical instruments and exhibits on the Observatory ground floor, we exited the building and prepared to leave for home. A parting shot is shown at left - a 3-frame HDR, combining 3 different exposures to recover details in highlights as well as shadows. The 40" dome is at center, with the steps leading into the north side of the Observatory at left.

Note that our tour happened on Wednesday night, September 26th. A few days later on Monday 1 October, the doors were padlocked and the Observatory shut down. The University of Chicago continues to search for a buyer that would keep the astronomical mission of the Observatory and the nearly 80 acre lakefront site. The search continues... By the way, our guide on that evening, Chuck Flores, is quite the photographer himself, and has created some dramatic time-lapse sequences of behind-the-scene goings on of the Observatory. His Vimeo clip to Yerkes activities can be seen here, and a sad tribute to his former employer here...