90 replies to this topic

[CHASLX200]

They were all good in those days and were pretty consistent too dale

Sorry...not in my experience...and I was around in those days.

True.

Chas

[tim53]

They never did use a faucholt tester or a ronchi tester or what did they test there mirrors with in the 60,s and 70,s dale

I'm sure they used at least a foucalt tester, and I saw the ronchigram that Ed Beck took of my 12.5" Cass optics that I bought ~1990 (he was a former Cave optician).

Maybe Dick Parker or Dave Groski could comment, but my understanding is that most of these tests are qualitative, unless one goes to a lot of trouble to calibrate them. And even then, the measurement techniques are subject to errors inherent in the devices built/used to make the measurements.

On the other hand, double-pass autocollimation has been around for a long time and could have certainly been used by any of these companies' opticians. But it's a dimensionless technique. You can certainly see poor figures with it, but beyond about 1/10th wave it's hard to see the errors. ...but when the mirror's that good, it hardly would matter anyway.

Measuring errors below 1/10th wave probably requires expensive equipment that most of the old companies didn't have or couldn't afford.

-Tim.

[DJD57]

I bet you have a good mirror in yours dale

[DJD57]

Well i have had a edmund criterion cave meade old reflectors and were all better than average and better than most mass-produced mirrors they make now dale

[tim53]

Judge for yourself! (scroll down to the end for some planetary imaging I've done with it) My 12.5" Cass thread



-Tim.

[DJD57]

I agree there methods were not up to date as they are now dale

[clamchip]

It's fun to clean the mirrors in a 40-50 year old scope and examine a defocused star and planetary detail. Like a box of chocolates, some are good, some are not so good, and then we have the ones to die for. Coatings that haven't deteriorated are rare, and the optical tube assembly construction, focuser, secondary and secondary support all have an influence. The image formed and then magnified by the eyepiece is what I use in my personal survey and I have my own favorites. Sometimes it can come down to which side of the focuser the finder is on!

I was looking back through old catalogs and only one stated double pass auto-collimation, that was Coulter.
Cave's company policy is to never over advertise quality by means of fractional wave lengths.
Optical Craftsmen had a exclusive 1/100 wave Caustic tester and 1/20 standard and optional 1/40 mirrors.
Edmund, "better than 1/4 wave"

Robert

[DJD57]

robert i have a old meade #628 6f/8 that dates before the rg reflectors came out and when i got this mirror the owner said it was never re-coated so that is 30 plus years and the mirror still looks new dale

[clamchip]

Hi Dale.
My OC Discoverer mirror looks like new and I don't think it's been recoated since it was made in 1969.
Problem is how do we know how good the coatings are?
Ability to see low-contrast planet detail is all I can go by and planet colors, if rich and not washed out looking.
I'm not sure if the coatings evaporate over time? airborne chemical action or if it is a mechanical process from cleaning and occasional dew condensation-evaporation.
10-15 yrs I think is the average coating life and if so mine are long overdue I guess.

Robert

[DJD57]

i just got mine and the owner said it was well kep t and kept clean with not being outside dale

[charles genovese]

Picked up a Starliner 14" observatory cass and fork mount with pier at an estate sale in the mid 90's- dirt dobber nests and all(don't remember the price but wasn't much). Swapped with Tom Dobbins for a 9" Mak. Dobbins did a big restoration- optics were garbage! had to be redone. Fiberglass tube was too thin to even hold collimation. Fork mount- garbage with huge design flaws- rebuilt and modified extensively -would work OK now-but is a giant doorstop (I have a lot of those!) Maby the german equatorials and newts were OK

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[DJD57]

Nice mount i bet it can hold a heavy tube for sure dale

[Datapanic]

Okay guys and gals, just for kicks, I'm a gonna go down to the 1100 block of S. Columbus and take a pic of where Star-Liner used to be first thing tomorrow morning!

It's sad these companies are just gone. When I was a teenager with a little under 600 bucks to spend on an 8" scope, it was a serious toss-up between the Cave 8" Lightweight Deluxe and the comparable Star-Liner. I forget why I went with Cave, maybe it was better communication, just don't remember, but the Star-Liner mounts did look nice, and their Deluxe was 1.75" shafts opposed to Cave's 1.5" shafts. I guess the ultimate would be a Cave OTA on a Star-Liner mount with Cave Legs to roll it around.... Who KnOws!!!

[DJD57]

THEY were classics in everyway and the starliner mounts were rigid and strong dale

[rmollise]

Nice mount i bet it can hold a heavy tube for sure dale

Uhhh...Charles just told you it _couldn't_, and he's actually had his hands on one of these mounts.

If you like these old scopes, that's fine...but they were hardly a paragon. Some good ones for sure--Cave, some Crtiterions, some Edmunds--but many poor ones as well.

Hell, I love the looks of these old warhorses, but I have used enough of 'em over the last 45 years to go in with my eyes open.

Often they were SEVERELY undermounted. My experience is that the average 60s mount is heavy, yeah, but also shaky.

Optically? Cave is tops. Not every mirror even they turned out was good, but many were very good--depending on the vintage. Edmund and Dynascope used the same mirror supplier, Upco, and these were usually very good. Star-Liner and Optical Craftsmen? CRAPSHOOT all the way.

[DJD57]

i have ahd most od them, the criterion was not the best mount in those years. The meade mount on the rg series was a stronger better made mount and edmund was even worse than the criterion but the cave starlinerwere up in the top 3 in those years in the 70,s for there size and were able to handle alot of weight, dale

[tim53]

It's funny, the different experiences we all had.

I BUILT a lot of the early Meade 628s 645s and 826s, and at the time I thought they were pathetic compared to Cave and Optical Craftsmen, which I had some experience with as well.

Now, though? I'd buy one if I have the room and the price is right.

Greg had a bad mirror in an Optical Craftsmen Connoisseur, so he parted out a great scope and replaced the mirror. I'd have replaced the mirror - preferably with one I made myself - and kept the scope intact. Those don't come up for sale very often. And if you can find one with optics by R. E. Brandt, you've got a real winner. I've had two OC 8" f/6 mirrors, one in the original OTA and one now in my Springfield (I parted that one out when it was only a few years old, so it wasn't a "classic" yet), and they are both excellent mirrors.

My 8" f/7 Cave lightweight deluxe is a very nice scope with excellent optics as well. And though that 1" shaft mount is too light for the scope (especially with rotating rings!), if I balance it well and it's not windy, it makes a good planetary imaging platform.

I've had several SCTs, both classic and modern, and though they are sometimes very good (and more flexible for different types of imaging/observing), they can't beat a good Newtonian for planetary, what I do most. I made parts for 2080s and 2110s for a while at Meade in 1982, and I hated them then (too much "hand work" needed to put them together and get them to perform well, at the time), but I have a 2045LX3 now and love the little guy.

Last but not least, I used to scoff at the Japanese import refractors. Kept doing so until I decided to try out the Mayflower 76x1200 I found on CL a few years ago. Now I've got a bunch of 'em, and one of my absolute favorites is a mid-80s red-tube Tasco 14F. I haven't found any of the small refractors that I've bought to have anything but very nice optics, and 2 of them - 90's Meade and Tasco - are beat to snot jobbies with plastic parts!

This stuff is fun, buying and trying out, and reselling these old scopes!

That fork mount from Star-Liner looks almost like a prototype or a one-off. Reminds me of the Dynamax 8's fork mount.

-Tim.

[clamchip]

Today it's easy to look back and smile, or have a frowny face. I look at the past with a smile. Wooden airplanes, seasonal crops growing on Mars, sun orbiting the earth, outdoor plumbing, 3 channels on the TV, etc.
I enjoy the past and just accept what we call faults today. It's the way it was and is part of the whole experience of using these pieces of our past.
Russell Porter spelled out the "bottleneck" very clearly, I don't see this vital area addressed properly on many commercial mountings. Did they fall asleep in class? they didn't read ATM I II III? like I said I don't care but I do wonder.
Some were in the know, mostly ATM'ers and the big observatories. Thrust bearings did start appearing, Optical Craftsmen being one of the first I know of, Pacific Instruments, Schaefer, and Byers.
Here's a Bill Schaefer mount, I circled what's missing on most of our oldies:

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[rmollise]

i have ahd most od them, the criterion was not the best mount in those years. The meade mount on the rg series was a stronger better made mount and edmund was even worse than the criterion but the cave starlinerwere up in the top 3 in those years in the 70,s for there size and were able to handle alot of weight, dale

Depending on the particular Cave or Star-Liner telescope and mount in question, they could be sufficient--or not. The one that came with my 8-inch f/7 Cave was on the Not side of the equation.

[tim53]

Robert:

Well, you got to water your crops if you want them to survive!! THAT's why we haven't found life on Mars!

[CHASLX200]

Picked up a Starliner 14" observatory cass and fork mount with pier at an estate sale in the mid 90's- dirt dobber nests and all(don't remember the price but wasn't much). Swapped with Tom Dobbins for a 9" Mak. Dobbins did a big restoration- optics were garbage! had to be redone. Fiberglass tube was too thin to even hold collimation. Fork mount- garbage with huge design flaws- rebuilt and modified extensively -would work OK now-but is a giant doorstop (I have a lot of those!) Maby the german equatorials and newts were OK

I owned the Starliner 2" shaft mount back in the 90's. The mount did a ok job of holding my 10" F/8.3 Newt that Starliner made for me. But like all of the mounts back in the day, and i've owned Cave, Meade, Parks mounts and they all had slop of some type. The drives and the clutch on all of these mounts were the bigggest problem.

Chas

[DJD57]

Tim i have one of those meade 628 6f/8 and it,s a gr4eat scope i never tested it but i bet it,s 1/8th wave or better? i have no problem in steady nights seeing saturn at 310x and the moon is sharp at that power, the stars are identical on both sides of focus? i have heard coulter and cave opticians came to help meade make there mirrors after they went out of business in 1978 or so dale

[DJD57]

my meade 628 has slop for sure especially when moving the scope in RA only and only on one direction but the DEc movement is smooth as can be dale

[tim53]

We had a handful of former Cave employees come to Meade, but none of the opticians did. I believe that the early Newts had Coulter mirrors in them, as Meade didn't have an optical shop of its own until they moved to the Irvine facility around 1980. Then, they made their own mirrors.

-Tim.

[DJD57]

i am not sure tim if mind was 1978 or as late as the early 80,s the owner said it is around 1980 so either the mirror was made by meade or coulter as you said which i heard is not good? Did the coulters mirrors back them sub standard like 1/2 wave? dale