I picked up a Surplus Shed 127mm doublet in a “cell” with plans on using this for my first scope build. How would I be able to collimate this with in the tube. Are there commercially available devices that I could buy or is this something that I need to make myself. Any and all help would be appreciated. Thanks Jack
Collimate Surplus Shed 127 mm lens
Posted 17 January 2020 - 09:31 PM
My two cents...
Search for a collimatible lens cell for a lens of this size ... or a lens collimator.
As long as the cell you already have holds the two lenses firmly in place, a collimator may work just fine, as long as you can adjust the lens cell's position on the tube.
So, if that's your situation, you'll find laser collimators as well as simpler "Cheshire" collimators that you can use for your purpose. Instructions for their use should be included.
Incidentally, I bought a collimatible lens cell (as did at least some others here on CN who have built scopes from the SS 127mm lenses), and it typically holds the lens assembly in such good enough collimation that I rarely need to re-collimate. But collimatible cells can be pretty expensive!
Posted 17 January 2020 - 09:36 PM
I haven't done this yet, but I have such a cell myself and will need to someday. In researching how to do this I found a thread asking about collimating a classic refractor. In it DAVIDG described a process that struck me as one of the most reasonable sounding method.
You can find this post of his here.
Edited by jtsenghas, 17 January 2020 - 09:37 PM.
Posted 17 January 2020 - 11:35 PM
Hello fellow refractor builder, Check with Scope Stuff in Cedar Park, Texas. They sell an eyepiece type collimator for under 30.00 dollars. I have use it to properly line up all my refractors. Some of my refractors had the cells that were able to be adjusted with the adjustment screws in the cell. Some of my homebuilt stuff had cells that just held the lenses. I had to square in the cells with the purchased collimator It really was not that difficult. I later used JB WELD to set the thing to the tube on the focuser end as well as the objective end. I have used these telescopes quite often, and it works.. It may sound like a silly way of doing it, but it works. I did this because I have no skills in machining, and It was not expensive to do. It worked for me.
Hope this might help you with your project. Scope Stuff has a site on the computer. I have bought stuff from them over the past 15 years, and I highly recommend that company. Andy in Arkansas.