OMI: 48" Dob project - Installation

48" Dob project (Installation)

« return to 48" main page

April 20, 2008 - James Mulherin

Stasi and I just returned Saturday night from a very successful trip to install Jimi Lowrey’s 48” Dob in S.W. Texas. We left Iowa City on Saturday morning, April 11th (2008) with a loaded 29’ U-haul, car in tow. After something over 1300 miles we pulled in to Ft. Davis at 7:00 pm Sunday evening, just in time for dinner with Jimi and some of his friends at the Limpia Hotel. The drive down was uneventful and smooth but we were relieved to have arrived with the scope at its final destination.

After a good nights rest we reported for work at Jimi's place first thing Monday morning. The plan was to get started at 9:00 am, which we did. The scope was off loaded from the U-haul onto a flat bed truck using a construction site fork lift. While we unloaded the scope Jimi and his crew drove a crane truck up to the observatory and positioned it to off load the scope parts from the flat bed truck into the observatory. The observatory is located up the mountain from Jimi's house. There are a couple of switch backs on the road up to the house then one last switch back and a couple hundred yards up a 20% grade to the observatory. If you didn't know better you'd swear there was no way either of the trucks would make it up that last dusty, rocky bit to the observatory but, thanks to some skilled driving, the trucks went right up.

At the top there was just enough room to position both the crane and flat bed truck to swing the crane boom over the pick points and the center of the observatory. I stood inside the observatory and directed Jimi, who stood in the open door and directed the crane operator. We flew each part into the observatory for assembly: first the ground plate, then the rocker box, side bearings and cell, primary mirror and finally, the upper cage and truss assembly. We completed this part of the installation by lunch time!

By dinner we had completed the wiring and the rest of the fiddly bits. We had first light that evening. Before the installation trip I told Jimi we'd have the scope on the sky the same day we did the installation. Jimi thought I was nuts. When you see the photos you'll see why. But I've done this before and it's quite impressive what you can do with the right equipment. That night, as soon as we could see Polaris we did a star alignment, looked at a few bright objects under a moon that was just a few days from full then called it a night. It was a long day and I was worn out, but very pleased with the whole operation and everyone involved. It was a good day.

Jimi and his good friend Van went up to the observatory at 3:00 am that morning and observed the moon and some other bright objects. According to Jimi, using 24 mm Naglers in the Denkmeier bino viewers was like flying over the moon on an Apollo mission. I got a better look at the moon the following night and had to agree. The 48" mirror provides high resolution views of the moon in 3D thanks to the Denks.

Here are a few comments from other observations we made under near full moon conditions:
The double/double system, Castor, in Gemini is split into four components and the brightest star is VIOLET!
In the Cat's Eye nebula you see pinks and greens.
In the Eskimo nebula you can see filaments ("fur") in the hood of the parka.

Jimi's best comment: "This primary mirror is hittin on all cylinders" sums up the optical performance very well. With the Paracor in the focuser stars are pin points with 4 crisp diffraction spikes on brighter stars. The color we saw under the full moon sky is a good indication of the light grasp and contrast that the optics will provide on a good dark night. I expect to hear from Jimi with some incredible observations during the upcoming new moon period. Jimi is awaiting new moon with great anticipation.

I'd like to thank Jimi and his wife Connie, his friends and cohorts for their help during the installation and for showing us a good time during our stay. Jim Chandler was a big help during the unloading, loading and craning operation, and he's an Argo/ServoCat expert. Gary Meyers of StellerCat, although not present physically, was on the spot with technical support the few times we needed his help. Van Robinson volunteered to run my camera while I was busy with the installation. Thanks to Van we have these pictures to post. Thanks also to Tom Hobby for taking more pics on the last night. One of his photos will make the cover of the June issue of Astronomy Technology Today. A big "Thank you" to Yuri Petrunin of Telescope Engineering Co. for providing an excellent primary mirror. We all have great expectations of the optics.

And, finally, a huge THANK YOU! to Jimi and Connie for hiring OMI and our team take on this project to build Jimi's dream scope! Dave Pasley designed the scope and my brother Toney Mulherin manufactured the beast. We all thoroughly enjoyed the challenge and are very proud to have been a part of this project. Stasi and I will be back to Ft. Davis the first week of June for the Texas Star Party and some dark sky observing with the 48”. I’m really looking forward observing with the scope under dark skies and to seeing everyone again.

Jimi's house and the telescopes new home; a 32'x32' roll off roof observatory.

James Mulherin on Monday morning with a cup of coffee and a truck load of telescope ready to go to work.

Loading the telescope parts on a flat bet truck for the trip up the hill to the observatory.

From left to right: The rocker box, primary mirror in its crate, the ground board and secondary cage and the rocker bearings and primary cell loaded and ready to go up the hill.