I bought an NGF-55 two-speed focuser for my SN-8. Meade saw fit to include plastic junk with the OTA and it was ruining my observing. The JMI NGF-55 was a drop-in replacement. It cost $300 delivered with the fine focusing option. It has worked reasonably well. A couple of problems: the website photo showed dual thumbscrews on the drawtube to hold the EP, but the focuser only comes with one now. The inside of the drawtube and extension tube are shiny smooth black anodized aluminum with no filter threads on the extension tube. Had to paint the inside of the extension tube and have it threaded. This focuser sits about 3/4" lower than the stock unit. With extension tube installed, I have to raise a 2" Axiom EP up a bit to bring it to focus. It's OK with 1.25" EP's, and too fast an OTA to use most 2" EP's without a Powermate anyway. The supplied thumbscrews for the extension tube have dimpled ends that will mar an EP barrel, since the extension tube has no compression ring like the drawtube has. The reducer has a single thumbscrew and compression ring to protect 1.25" EP's.
I use a Baader Click Lock with 2" nosepiece to hold my 1.25" EP's and binoviewer anyway. It's much better than the JMI extension tube with JMI 1.25" reducer. The focuser comes standard with the extension tube and reducer, so cannot leave it off for credit. You may need a longer extension tube than standard if you intend on using 2" EP's with the focuser. It seems to be optimized for camera use, which is no surprise as the SN-8 is an astrograph OTA. I'm going to mount some cameras after my move anyway.
Anybody else getting a JMI focuser for a Newtonian might want to check out the issues with internal threading and blackening of the tubes. Also, remember the lack of compression ring in the extension tube.
The nice thing: there is plenty of infocus for me to use my binoviewer with simple Barlow type cell at the front of the bino. No intrusion into the OTA at closest focus like the stock unit. The 10:1 fine focus option works quite well at high powers. No flopping and bending out of collimation with heavy binoviewer. It should hold any reasonable sized camera up to a full size pro 35mm SLR like a Nikon F2 or Canon DSLR with no problem. Electric focusing with digital readout is an additional option. The SN-8 is performing to its optical limits now. Have had no need to adjust the focuser tension, in fact JMI warns against doing that. This is the type focuser that Meade should have included with the SN-8 and SN-10 OTA's.
good luck,
Phil
I use a Baader Click Lock with 2" nosepiece to hold my 1.25" EP's and binoviewer anyway. It's much better than the JMI extension tube with JMI 1.25" reducer. The focuser comes standard with the extension tube and reducer, so cannot leave it off for credit. You may need a longer extension tube than standard if you intend on using 2" EP's with the focuser. It seems to be optimized for camera use, which is no surprise as the SN-8 is an astrograph OTA. I'm going to mount some cameras after my move anyway.
Anybody else getting a JMI focuser for a Newtonian might want to check out the issues with internal threading and blackening of the tubes. Also, remember the lack of compression ring in the extension tube.
The nice thing: there is plenty of infocus for me to use my binoviewer with simple Barlow type cell at the front of the bino. No intrusion into the OTA at closest focus like the stock unit. The 10:1 fine focus option works quite well at high powers. No flopping and bending out of collimation with heavy binoviewer. It should hold any reasonable sized camera up to a full size pro 35mm SLR like a Nikon F2 or Canon DSLR with no problem. Electric focusing with digital readout is an additional option. The SN-8 is performing to its optical limits now. Have had no need to adjust the focuser tension, in fact JMI warns against doing that. This is the type focuser that Meade should have included with the SN-8 and SN-10 OTA's.
good luck,
Phil
