Quote:
Originally Posted by astro744
My SW focuser is the black body type. The focuser body height is 60mm. A 12mm collar with a male thread and single locking screw screws directly into the draw tube which is part of the focuser body. It is this collar that has the internal stop preventing any 2" accessory from protruding further into the draw tube. A 45mm 2" eyepiece adaptor (labelled as such) with a tapered base connects to the 12mm collar and is held in place via the single screw. The entire adaptor can be rotated by loosening the single screw. I believe this is where one would replace the 2" adaptor and add a shorter T-Ring if wanting to attach a camera thereby gaining 45mm less the thickness of the T-Ring.
Im not sure of the purpose of stop inside the collar but it prevents any 2" accessory being lowered further into the draw tube. My Astrosystems laser is 2" diameter and just over 100mm long (4"). The approx 5mm Barlow attachment clips onto the end of the collimator. To see the return beam whether with Barlow attachment or not I need the end of the collimator visible from inside the OTA but because it is unable to travel that last 60mm it means it cannot be seen at all making collimation impossible with this particular collimator. (It woks very well on my other custom 10" with GSO focuser).
In fact even a Paracorr cannot be fully inserted, something which for f4.7 could be more used than not. The Paracorr 2" part is 60mm long and sticks out 15mm because of the collar meaning I cannot reach focus with it in place.
As I said I bought this for the kids and they will be using without a Paracorr and so far it has provided some very pleasing views and I am happy with it as it is relatively light and small for a 10" telescope.
If I had access to a lathe (and knew how to use one) I would bore out the stop and problem solved, (or I'll just get some 1.25" collimation accessories).
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This is true.
My Paracorr did not fully go into the focus tube either. (SW 10" DOB).
I read somewhere about a hack, to file around the tube enough to allow the Paracorr to fully insert.
This I did and now all seems well.
But I too am wondering why it was there in the first place.