Ok, so I was too lazy to take out my mak 150 early and let it cool down and too lazy to take out my T-Rex.
I did take out my AT72ED on Manfrotto tripod. It suits my lazy ways too. First attempt with 56mm plossl, 2” 3nm filter on the end of the plossl, Baader digiscoping adapter, NVD Micro in adapter. This came to Focus with my focuser drawtube racked out about 3 1/4 inches. Could see the focal reduction at work. Nice bright image of M42. Could make out ic434, HH lump, and flame.
Next I put the Antares .5x focal reducer on the end of the plossl and the 3nm screwed into the focal reducer. Had to rack in the drawtube a good inch but all came to focus easy. Detail on HH was better. Image smaller for sure. It would not come to Focus with focal reducer on the end of the diagonal. Not enough back focus but worked very well with FR on end of eyepiece barrel. I don’t know the TFOV and didn’t measure it. The three belt stars of Orion fit in the center of the view with a lot of room to spare on each side. Rough guess would be easily over 5 degrees. I’ll try to get a better guesstimate later. I can compare to my 8x42 (have to look this one up again but over 7°) and 10x50 (6.1° TFOV) bino views and get a better idea. I did see some vignetting but edges actually looked pretty good and some of the apparent vignetting might have been from the eyecup opening being a tad smaller than the envis lens. The moon was up nearly 3/4 and positioned above and to the right of Orion. I am in Bortle 7 skies. Not bad for moon and LP to see as much detail as I did. The 3nm helps in those conditions.
Next experiment though will be on the mak 150 for sure. Very interested to see what reduction I can get with the combination here. That scope is 14lbs compared to 25lbs of my 6” F/5.9 and lately would rather use smaller and lighter scopes. If I can reduce it enough to give me some good narrowband summer nebula views that aren’t too noisy I’ll be very happy. At F/12 the Ha starts to get very noisy and my Micro has no adjustable gain. I only have adjustable gain in my 25mm tube devices. I think I can effectively reduce my F/12 mak to somewhere near F/3.8 using both .5x reducer and the Micro afocally over the 56mm plossl.
All in all it was a success for reduction and focusing confirmation. Will add more as I find out more. A few minor kinks to work out like maybe plugging the envis lens all the way inside the eyecup opening to keep from vignetting or possibly removing the eyecup and make my own small shroud to block stray light and keep from vignetting. The Baader adapter is light weight and has many adjustments to easily position the NVD where you want above the eyepiece. Has an adjustment that allows tilting the NVD directly off the eyepiece in click stop increments too for easy compare of regular eyepiece view to afocal NVD view.
Edited by Vondragonnoggin, 15 March 2019 - 02:09 AM.