Telescope-Making Projects
By Zane Landers
I’ve recently completed my 24″ f/3.5 homemade Dobsonian telescope. The whole scope can be set up by one person in about 25 minutes and fits in the back of my minivan easily. I had to learn how to weld and work with metal to build it, as it uses a homemade mirror cell and significantly more metal parts than anything I’ve built previously. As of the time of submitting this, I’ve gotten the scope out 3 times and had great views even under partial cloud cover and without a light shroud, which was delivered this week and should significantly improve contrast. The Orion Nebula is, in fact, pink under dark-ish skies.
However, I’ve not been content to stop there, so in the last month I’ve begun preliminary work on pair of slumped primary mirrors – a 16″ f/3 as practice and a 36″ f/4, both of which are thin plate glass meniscii (basically shaped like a contact lens with a concave front and convex back). You can read more about how those work here – meniscus mirrors are a relatively established concept in the amateur telescope making community these days. I can barely lift the 36″ blank, otherwise I would’ve sprung for a 42″ instead. The 36″ will probably be a multi-year project due to the infrastructure and effort required. The finished scope will stand about 13 feet tall and require a trailer, assuming I even finish it in the first place. I am not expecting fabulous optical quality due to my mediocre skills but if the scope can handle 30x per inch that’s all I really need.
Lastly, I’ve begun to teach more people the seemingly-forgotten art of making telescopes. With the shortage of new equipment due to pandemic-induced supply chain issues and the all-time high demand for telescopes, making your own is an increasingly viable and worthwhile option. This week I flew to visit my friend Jordanne who is currently working on a 17.5″ Dob, and we finished the mirror cell together.
You can follow her work here: https://www.cloudynights.com/topic/746807-175-f45-truss-tube-dobsonian-build-first-build/
I have another half-dozen students working on scopes at the moment – half are even grinding their own mirrors!
Clear skies and cheers to a good 2021!
