Eighteen years ago I suffered an acute attack of aperture fever after viewing M51 through a 17.5" Discovery Telescope. There was one thing I didn't like about the experience - climbing the ladder. So I bought the largest scope I could that kept my feet on the ground - a 15" Obsession Classic. That scope has served me well for all of the intervening years since and I've enjoyed hundreds of hours of excellent observing with it and it has done a wonderful job of keeping my aperture fever in remission. Returning from a dark sky trip in November of 2017, the symptoms of aperture fever overpowered me again, but I still wasn't crazy about hauling a ladder everywhere with me and climbing up and down it dozens of times each night. I wondered if it was possible to get a larger aperture scope that would provide enough benefit to justify the cost and still be able to keep my feet on the ground. I began to talk with opticians and scope builders about my "ultimate telescope" with a basic list of requirements.
- Largest possible aperture without a ladder or step stool of any kind.
- Portable - Heaviest component less than 70 pounds
- Compact - Needs to fit into the back seat area of my GMC truck
- Tracking will be provided via an Equatorial Platform - no Servo Cat, or Go To system
After several conversations with Mike Lockwood about the goals for this telescope and the fact that I'm not the tallest person in the world, I placed a deposit with Lockwood Custom Optics to begin the production of a 20" f/3.0 primary mirror and matched 4.8" secondary mirror. With an equatorial platform taking up about 6" of the eyepiece height, the focal ratio would need to be short in order to keep me off of a ladder or stool while observing. At just 1.25" thick, the mirror set also saves on the weight of the scope - important for loading/unloading without wheelbarrow handles. While Mike told me that it could take 6 to 9 months to complete the optics, I got a message from him just 3 months later saying that they were complete - well ahead of schedule.
For the selection of the structure, experience taught me that I needed to select a builder with significant experience building large aperture telescopes at f/3.0 and faster. The list of builders who have this sort of experience is very short indeed - especially when limiting my search to builders in the United States. After discussing with three builders, I selected a Spica Eyes structure built by Tom Osypowski of Equatorial Platforms. Detailed information regarding his structures is hard to come by. I learned when I picked up the telescope that mine was number 39 - so that explains the lack of a lot of information or coverage. There just aren't many of these scopes out there. They're truly handcrafted, one at a time. I was a previous customer of Tom's - he built the Equatorial Platform that I use. I have been so pleased with the platform's quality that I had an extremely high level of confidence in the structure that he would build. I contacted Tom on February 1st and received notification that the structure was complete on May 19. Build time was 3.5 months from the initial contact. My current client in California is only about a 2.5 hour drive from Tom's shop so I made arrangements to drive my vehicle up and pick up the telescope over Memorial Day weekend. I was in love with the scope at first sight. Four days after driving from northern California to Phoenix, I was headed to the magnitude 7+ skies of Portal, Arizona for first light. The weather cooperated as perfectly as I could ask. Here are my thoughts and experiences thus far. Constructed entirely of aluminum, the structure is the most solidly built and rigid dob I've ever laid eyes upon.
The full setup
Laid out on the floor at home prior to packing up, there are four main parts to the setup. The telescope is stout - 189 lbs (85 kg) total weight, but it's distributed relatively well between the parts. The heaviest piece is the mirror box of course, at 73 lbs (33 kg) which is slightly over the design spec. The attached, heavy duty handle makes it easy to move the mirror box about though. Not pictured are the removable 30" altitude bearings. Note the mirror cover locks in place to protect the optics. There's a matching mirror box cover for the back side that slides in place and keeps dust out when the telescope isn't in use.
Assembled in the house, and placed on the EQ platform, the telescope has an eyepiece height at the zenith of just 63.5" (161 cm) - perfect for me.
The telescope makes liberal use of connecting hardware from Aurora Precision - and it's insane how well machined the pieces are. The handscrews and truss connectors to the mirror box are machined to fit tightly together in the same orientation every time.
The upper truss connections are even more impressive to me. With two "registration" pins on each of the four upper connections, the UTA literally snaps into place on the truss poles. Even before tightening the knobs, the whole structure is quite rigid. Once tightened, the entire telescope feels as though it's been machined out of a single block of aluminum - incredibly rigid.
The mirror cell is also from Aurora Precision and is best described with the phrase "industrial art". It's well crafted and heavily constructed. I suspect that the mirror cell actually weighs more than the 1.25" thick optics that it supports. Only two collimation knobs are used to achieve alignment, as the point nearest the ground is bolted directly to the mirror box and has the ability to pivot based on the movement of the two collimation knobs mounted at the extreme upper corners. It is a brilliant solution and so easy to use. The whiffle trees are substantial and move easily, supporting the mirror perfectly. Finally, there are two nylon screws near the top of the mirror box that are used to secure the mirror in the cell during transport.
A single 120 mm fan pulls air away from the mirror and is operated with a variable speed potentiometer and on/off switch. The fan is so well isolated that no vibration is detected at 375x magnification. A 12v battery built into the bottom corner of the mirror box supplied power for all 4 nights out. Notice the batter charging port mounted in the mirror box just below the handle. This port is wired to also supply 12v power to other accessories, though I've not used it for anything yet.
At the business end of the telescope, an Astrosystems Super Duty II spider and secondary holder keep the large 4.8" secondary in place without issue. I was happy to see the hub at the center is welded to the spider vanes to inhibit the tendency to twist under the weight of the secondary. The upper cages is made of aluminum as well, and provides a mounting location for the Telrad, 60mm Stellarvue finder and Feathertouch SIPS focuser.