Thursday, April 23, 2009

Ranger Transformation Project Re-open

Today, I found another secret screw on my Ranger, now I could remove the whole back assembly including the dovetail, the draw tube and the focuser. The thread is M77 (or M76? or 3inch? pending confirmation) male and now I have a few more centimeters!

I placed my NGF-S there, and I can reach focus with my 2" mirror diagonal + Pentax SMC XL 40mm, I can reach focus with my 1.25" accessories... I just need a little bit more out-travel but then it's easy... I can make a slightly longer adapter to connect the NGF-S and it's done.

The adapter should look very much like this one:-

which I have made for my Borg 45ED II before. Of course, it's not M57 to connect to the OTA, but it's another specification: 12mm of M77 female thread.

So, if this project is implemented (i.e. make the above adapter), my Ranger will be able to take 2" eyepiece (new life indeed!), as well as motorized focusing which is especially useful for solar imaging with my Solarmax 40, that means I can sell my Borg 45ED II afterward.

Of course, the Borg is great for full disc imaging due to its shorter focal length, so I've tried to use a SCT reducer, but there is not enough back focus. I might want to try out a 0.5x binoviewer corrector to see if it works or not. If it works, there is no reason that I should hold this project.

I always want to find some use with my Ranger, and if that could be done, it's just perfect!

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