Last night I confirmed that Dudley do right likely helped design the Unitron 128 mount
The original OP has agreed to let me piggyback on his thread.....Thanks Bill!
The 128 arrived well packed and after 2 weeks of travel everything including the wood cabinets arrived safely. After a general cleaning of the OTA and mount....I did not touch the objective, the first light arrived last night. The objective is in nice shape with a few dew spots and dust but spacers intact. The AR coating is intact and nice shape as well. As you can see it is a older cell style.....I did check the newton rings under a CFL and they are off center but I decided to leave as is for now. The mount itself is missing the original counterweight but in great shape with everything else intact and original as far as I can tell. The replacement weights are interesting to say the least. Not surprising the mount is a joy to use and very smooth....the slow motion controls work very nice. The metal feet are intact but need some attention on their connection to the tripod.....You can tell this scope was enjoyed a lot but not abused. The wood tripod has the original spreader and besides the honest dings and dents is in good shape. A little murphy's oil soap is in order.
I need to clean up the finder optics but it is functional and the eyepiece has a double cross line reticle and the finder tube is chromed brass very heavy. The dewshield for the main OTA is also brass.
I started out the evening early with the crescent moon using a recently cleaned star diagonal and 25mm and 18.5mm unitron eyepieces. Very nice! As vega emerged it was time to view some diffraction rings......I used three eyepieces; a 18.5 Unitron and a 12.5 Unitron and a 12.5 Goto (both cleaned and ready). I did not have a eyepiece in .0965 that matched the F/15 FL to use for this so I decided to try two that were close. My comparison scope last night was a GOTO 105 that delivers, in my opinion, a very good star test. Well with no collimation or cleaning of the 128 objective all I can say is "amazing"! I moved onto Deneb in Cygnus and then Izar in Bootes......The 128 held its own against the GOTO with just a very slight edge to the 105 (lens not cleaned but collimated) So after collimation of the 128 a rematch is in order. As for color correction the 128 has a purplish hue.....the 105 at F/20 has less color but still a tiny hint.
My impression of this 128 is the lens performed much much better than I expected. (The only thing I did to this lens before tesing was to loosen the retaining screws so no pinched optics) In comparison to the 60mm F 700mm Unitrons that I have viewed with this 128 has better color correction. The mount no doubt is a keeper and I look forward to trying the 700mm models on it.
My disclaimer here on star testing comparisons is: It is fun at least for me......I cannot state that what I see you will......but we all know about the variables of star testing........I look forward to DPAC testing of all my objectives in the future but I for one certainly am entertained by trying to compare two objectives with the same eyepieces and star diagonals on a summer evening with the stars waiting.....Enough of that!
Edited by PawPaw, 25 June 2020 - 09:42 AM.