My Questar 3.5 Duplex is vintage 1984. It will accept standard 1.25" eyepieces. A couple of nights ago I used it with a Televue Delite 15mm eyepiece coupled to a PVS-14 night vision monocular via a Televue adapter. The night vision eyepiece works with the main scope but not with its finder. I'm in Bortle 6 with worse light pollution in the south. I centered Antares with a regular eyepiece using the finder and moved to the position of M4 which could not be seen in the finder. Switching to main scope view mode, M4 was not visible. I put it the night vision equipped eyepiece and there was M4 right in the middle of the main scope field. It was extremely bright with myriads of pinpoint stars. The center was resolved and many arms of trailing stars radiated out from the center reminding me of the cluster's nickname of the "crab globular."
So, night vision seems capable of converting the Q 3.5 into a decent deep sky scope... something it is not known for even in dark skies. I used a 12nm H alpha filter which is useful for almost any deep sky object. A 685nm IR pass filter shows increased contrast between sky and deep sky object, but won't show planetary nebulae. It is good for galaxies and clusters. A simple red filter increases contrast in general but is not as good as my H alpha filter although it is better than using no filter. I typically pick one of these three filters when observing deep sky objects with night vision.
Rick
