Telescopes

Right click on any image and select "Open image in new tab" for a larger version of that image.

30-inch f/2.7 alt-az Newtonian

During the winter and spring of 2022 I transformed my perfectly good 28-inch f/4 scope - see below - into a 30-inch f/2.7. 

Why? How? 

Click here to find out!


28-inch f/4 alt-az Newtonian  

Cover photo of Amateur Astronomy, issue #50. This is an 18 point, low profile floatation cell for the 28-inch diameter, 2 inch thick Pyrex primary mirror. The wiffle tree edge supports in this photo have been recently replaced by two posts at 90 degrees from the center of the mirror - almost exactly where the ends of the two wiffle tree arms are located. This arrangement works quite well as each post cancels the astigmatism created by the other post.  It's important that these two posts can rotate easily so they don't bind and build up stress on the edge of the mirror. This is a much easier side support to make than a wiffle tree.

The main design feature of the mirror cell is that it's moved by the collimation bolts, not just the mirror, so edge stresses don't build up during collimation. Thanks to Dan Gray for this design.

The 28-inch set up and ready for action at Logan Valley in central Oregon, July 2020. This was its first observing run after I upgraded it with Ed Allen's forced ventilation system.

The first night was exceptionally dark at Logan Valley, with several SQM readings at 22.00 - all the better to marvel at Comet NEOWISE at its peak!

For details, see the photo and design and 2016 drive update pages.

 

8-inch f/4 "Springsonian", a regular Newtonian with a fixed height eyepiece

 

There are two main ideas that led to this design - constant height eyepiece, and the entire scope is easily moved on wheels.  

However, the best part about this scope  is that the mirror is my first. I originally completed this mirror in 1969, and refigured it in 1980. It still uses most of its original mirror cell too.

 

 8-inch f/3.3 Newtonian

 

Third time is a charm - this is the re-designed 8-inch f/3.3 scope that was previously a single arm design. Now the scope works as it should and is a delight to observe with.  There are more photos and details about this scope on the Other Scopes page, and I'm proud that Jerry Oltion featured it in his  Astronomer's Workbench column in the October 2020 issue of Sky&Telescope.