Modifying a refractor

Hi All,

More a modification than a making question. I have a SV-102D refractor, and some Tak orthos I love. The require much more in-focus than a Meade 4000 Plossl. I also have recently acqired a Borg eyepiece turret. The Plossls come to focus fine (with a .125 inches to spare) but the orthos just can't go in enough.

I'm toying with the idea of taking the tube in to the local machine schop and having them trim 2" off the back and re-thread it. Then I though about possilbly purchasing a Bino-viewer down the road.

So the questions: 1) Does anyone have any experience with "Tube shortening" I can learn from? Any "gotcha's" I need to watch for?

2) How much shorter would the tube need to be for use with a Bino-viewer w/o a barlow?

Thanks for looking!

---Rob

Rob,

I've shortened a couple of refractors myself so as to use a binoviewer without having to Barlow it. I did it on my tablesaw, but I don't recommend the process.

You may have to move or remove a baffle at the EP end, and you may not have enough backfocus for some configurations without using an extension tube, but in my case it's worked fine!

James Adams