October 6, 2008
For about a year now OMI has been developing and planning the introduction of a 30 inch Dobsonian telescope. We just made the first formal introduction of the scope at the Okie-Tex Star Party last week. At this point the scope exists only in virtual reality as CAD drawings. We will begin fabrication of the prototype this month and plan to demo the working prototype at the Texas Star Party in April of 2009. I’ll post regular updates here as we work our way through the production of the first scope so stop by occasionally to see our progress.
December 21, 2008 update
We’ve made significant progress on the Evo-30 project. Dave Pasley has completed the design work and we have begun production of the prototype. As you can imagine, there is a lot of detail work in the electrical systems including the drive motors and encoders. Dave has completed all mechanical details down to the last screw. There will still be some detail work after we assemble the prototype, like creating a clean wiring harness, and making the shroud but these things are better left until we have the real thing to work with. Read more. . . .
January 27, 2009 update
Production has begun!
Last week Toney Mulherin started writing CNC programs and fabrication parts for the prototype Evo-30 on the bridge mill. There are three phases to production of the telescope parts. Phase one involves fabricating all of the parts that start out as flat plate. These parts are made on the CNC bridge mill. Included in this list are things like the ground plate, the rocker box bottom and walls, the primary mirror cell, spider vanes and secondary cage rings. Toney will complete phase one by the end of this week. Read more. . . .
May 14, 2009 update
2009 Texas Star Party Report
As promised we made it to the Texas Star Party with the Evo-30 prototype in tow. But, as is our usual custom, we took it right down to the wire in terms of schedule. We only had first light at Jimi Lowrey's place, about 3 miles from the TSP site, on the Saturday evening before the start of TSP. Once again, I owe Jim Chandler a debt of gratitude as he was instrumental in setting up the Argo Navis and ServoCat. I had forgotten to bring a critical component required to initialize the drive system: a USB to serial converter to connect to and load parameters into the ServoCat. Fortunately Jim keeps one in his tool kit and we were on the sky in no time. Read more. . . .
October 20, 2008
There are several types of aluminum coatings available for astronomical mirrors. These mirrors are used and stored in a variety of environments, which is expected to impact the longevity of aluminum reflective coatings. Environmental factors impacting this longevity include, but are not limited to, humidity, pollutants in the atmosphere and the storage environment.
Environmental factors often vary as a function of climate and storage practices. Examples of general climate types include; Desert Southwest (mostly dry, yearly monsoon), Mid-West (warm, humid summer, cold winter), Gulf Coast (hot, humid summer, mild humid winter). Some telescopes reside in permanent installations such as a dome or roll-off roof observatory. Some are stored in a trailer, garage, basement, or air conditioned house.
This experiment seeks to determine the general rate of deterioration of each of several coating types in various environments. Because of the diversity of environments, it is not expected that a hard rule for longevity can be established. However, it is our hope that the data obtained from various climates will allow us to arrive at a fairly representative life expectancy and to provide additional information on the effect of a particular climate. We also hope to gauge how much the life expectancy should be expected to differ from the average due to a particular environment.
Invitation to Participate in the Long Term Mirror Coating Study
Readers are invited to participate in the long term coating study. If you are interested please join the Yahoo OMIcoatings discussion group at
http://tech.groups.yahoo.com/group/OMIcoatings
Participants are not required to have an OMI coating on their telescope mirror as the samples to be studied will be provided in the kit supplied by OMI.
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In June of 07 we started a project to build a 48" Dobsonian for Jimi Lowrey in Ft. Davis TX. The 'scope is finished and has been installed at Jimi's observatory.
Jimi's 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.
We will present an article in the June issue of Astronomy Technology Today detailing the project from start to finish.
Read more and view gallery. . . .
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