Meade 628 Celestron C 4.5 Tasco 7T (Royal Astro) Tasco 7TE (Royal Astro) Tower 6335 76mm, 1200mm (Royal Astro) Eikow 77mm, 1000mm Carton 60mm Unitron 60mm Bushnell Sky Chief III (SLR) Edmund 3001 1970 Cave 8" f/7 Lightweight Deluxe Meade 300, (T)
Clint & Debbie Whitman (aveman JOIN US AT CSPAMP VII 8/1,2,3/14 Classic Telescopes, 9" f 10.6 AP Refractor ThePEARL, 1946 4" Tinsley Saturn Telescope. 1970 4" Unitron 155c,1954 100mm Unitron Brass 152. 1950s Nippon Kogaku refractors 5 CM, 6.5 CM. 1965 10" F8 Cave Astrola, G-11 ST2000xm Over 5500 posts prior to the CNC on 03/14/14
Quote:No paint on the lens retaining stop screws, 90% of the unitron you see and out of all the ones I have personally worked on had any paint on the set screws. Most of the time in the photos I see it looks like a drunk applied the paint. Not very indicative of a master optician! Barry G of D&G called me and we spent hours on the phone talking about dating Unitron objectives. He has been sent 100s of them over the years. Between us we came up with the same conclusions about dates based on Italic / Straight lettering, the lack of lettering, screw configurations and the 100mm vers 102mm questions. the red paint issue was discussed and Barry said it was very rare that he saw it and figured like me that it was a fad that a few people did to their telescopes. Barry Simon's 60mm is the earliest Italic lettered scope I have ever seen and all the Unitron I have see that were pre 1958 had no plastic knobs or wing nuts on them. All nickel plated brass parts.
What some may view as an argument I view as a different perspective.
Arcturus Observatory Belgium
Quote:In the absence of any informational history from Unitron, one other possibility for the red paint exists:
Perhaps a major dealer of Unitron scopes, lets say RVR Optical where I got several of mine, fine tuned collimation on the scopes that came thru his shop and he then applied the red paint as a way to help prevent collimation from slipping and to determine if anyone tampered with collimation. I can only remember seeing the red paint on "pre-ear" objective cell assemblies. Maybe the 60 mm was known for shifting collimation, who knows. Just a theory. This theory can only be proven if the "red paint" Unitrons could all be traced back to the same dealer.
Quote:That brings me to an other question: you see 60mm and 62mm lenses. Is there a difference in age?
Unitron 152c Unitron 140 TV-NP-101 Takahashi Sky 90 Takahashi FS102 William Optics FLT-110 Takahashi FS-78 TV 102 IS Celestron C-14 Meade LX200, 12" Sears Discoverer 4454 Sears Discoverer 6344
Quote:I have been told the 62mm indicates a slightly older age (mid-50s?). They are the same size lens as the 60mm, just a variation on how measured w/cell.
Quote:This may be another great question to ask the previous owner IF he or she is the original owner whether it came with the painted screws from the factory
Quote:Here is a prefect example Javagos retaining ring is not a threaded type, The screws with the red goo on them are to hold the retaining ring on and the lens in, then the small flat head set screws push it out away from the lens so there is no pressure on the objective. Then they lock the retaining ring in place. This allows the lens to be loosely held by the lens cell and that's all. The red goo would keep some folks from tightening the screws down and breaking the objective which is easily done and accounts for many clam shelled objectives you see. But these screws have nothing to do with collimation of the telescope. Now the BIG flat head screws on the lens cell flange those are another story! Where do you guys find these od flat flange adjustable Uni scopes? InterestingHere is my 1950s 114 purchased from the original owner who had it shipped from Unitron in 1959 with an invoice. No red goo,,, These type have a threaded ring and the three small flat head screws push out on the ring and lock it in place. (non collimatable cell)
Quote:About the red paint on the Polarex lenses.On the 6", 4" and 2,4" lenses from 1957 there is no red paint.On the 75mm Polarex (with the large focuser) there is red paint.Tomorrow I'm going to pick up an old 128. According to the sellers photos there is no red paint. I'll ask the seller the age of the scope.That brings me to an other question: you see 60mm and 62mm lenses. Is there a difference in age?
Quote: my 75mm unitron made in 1996 as i bought it from the original owner in DC..i have his bill of sale dated then when he bought it.
Quote:i would say your 4" was made in the late 80's to mid 90's
Quote: Detail of the 160mm Polarex lenscel 1957
Quote:I have wondered date of manufacture on this one.
9 screws in the retainer ring and Philips heads. Green color multi coating. No evidence of any red paint.
Quote:Clint, your picture of the large lens cell flange-is that yours and what model does it come from? And if I hear you right are you saying this type of flange (pictured here) makes the lens collimatible or not? So much info for my brain which seems to be getting smaller all the time! Thanks.
Quote: Xavier, I wonder if I am the only one who's eyeballs popped out of his head seeing a 6" Polerex!! Please post more photos, Look a real collimating lens cell, with lock screws!!
Quote:A possibility but I kinda doubt it. Looks like Roel's in this thread has the red paint and considering his is a Polarex that would seem that red paint was on both sides of the pond. http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4360156/Main/4357726
Quote:I am going to correct myself. Looking at Roel's scope in a different site does not show the paint. http://www.roelblog.nl/2012/01/nieuwe-telescoop-polarex-75mm-equatoriaal/
My observations, sketches and ATM projects: www.roelblog.nl