Roe 8" f7

Like I needed another scope...II

So I arrived at the 2011 Saint Louis Astronomical Society's Star BQ and it looked like a Gypsy caravan had setup in the lot. Turned out it was my good friend Jim Roe selling off a bit of his telescope equipment. As I walked up to say hi, I passed by what looked like a tall grey water heater on a three legged pipe.

A casual glance revealed an 8" f8 Newtonian telescope on an ancient pier mounted EQ head. It certainly looked like it had seen much better days but now It didn't even appear to be worth $49.95...

I did notice the "FREE" sign on it but I've been down that path before. I quickly scurried past trying to look nonchalant and uninterested but Jim knows I like to rehab scopes. This one had "Stay away" written all over it.

After the usual "propers", I looked through the piles of stuff he had on display. After a few minutes, I felt like I was back in the 60s' again. I think I got a kick start on the journey by that scope I passed by earlier. Jim had worked for McDonnell Douglas in the 60s' & 70s' while I worked there in the late 70s' and again in the late 80s'. When I was in the Air Force, I had the great good fortune to work on nothing but 50s' era aircraft. If you've ever worked on the stuff Jim and I had worked on, you would have seen the same construction style and craftsmanship in all that stuff on Jims tables - "Vintage old stuff".

I hate it too though. You know someone put their heart and soul into it when they built it and used it but now it's obsolete. Todays' equipment outperforms it by orders of magnitude. It's only good for museums or landfills. I really hate throwing that stuff away.

Well the StarBQ was great but as I was packing my stuff up, Jim comes by and says "Hey Grant, take this scope home. You'll really like it".

Damn, almost home free. I shouldn't have asked Thane about his trip to Florida. His response had only lasted a half hour. Short for Thane, fatal for me. I was now stuck with a great white, er, gray, elephant. Being the sucker for punishment that I am, I packed it up and took off. I hoped this was a case of the book being better than its cover.

What follows is another "Sows ear into a silk purse" project - enjoy!

(Image above shows the OTA mounted to my EQ6 tripod for optical testing).

(Click on images for higher resolution versions)

OTA

The business end. It even came with additional counter weights opposite the focuser. The mirror cell appears to be of the University optics design so that's a plus. The finder is essentially an 8x50. The tube is thick commercial fiberglass. The mirrors... yeah, well, there's a story here too and you'll find it below.

Mirror Cell

Spider and diagonal holder

Equatorial Head

The mount consisted of a typical 60s - 70s custom made EQ head on a three legged pier. Typical example of McDonnell Douglas style construction and craftsmanship. Unfortunately, it's going on the pile of other EQ heads that I can't bear to throw away, yet can't really put to good use.

Pier

The primary was pretty well gone. Star testing showed just blobs of light for stars anywhere between 56x and 177x (I didn't do any further testing after that performance). The image on the left is front lit while image in middle was backlit. The original sticker was still on the back. The handwriting says "122662". I'm not sure if this is a date code or serial number. If it's a date code, it could mean December 26 1962 - That would be about the right era for both the mirror and the coating.

It occurs to me that if it was actually coated in '62, then this mirror is at least 50 years old - Huh.

Diagonal

Mirrors

Primary Mirror

When the OTA is mounted to the EQ6 on the tripod (as seen in the image at the top of the page), the eyepiece is nearly 6' off the ground when the end of the OTA is pointing above 45 degrees altitude. The top mounting plate of the pier is the same height as the top mounting surface of the tripod.

So, rather than shorten the tripod, I gave the pier and EQ6 tripod to SLAS member and master machinist Bill Davis for some custom work.

I asked Bill to shorten the pier by 6" and make an adapter for the EQ6 tripod head. Some of the other scopes I have will benefit from that arrangement also.

The EQ6 tripod legs take up most of the patio so the pier will definitely reduce that footprint. I just hope it's as stable as the tripod.

Pier overhaul results TBD ...

The pier on the other hand is going to be reused.

The diagonal was in no better shape than the primary. Image on far right is backlit. The scope was put aside until the mirrors could be recoated.

The diagonal is held in place by what looks like a classic Novak four vane spider and diagonal holder. This is one of those funny holders that have four adjustment screws. Actually, they work pretty well once they were cleaned up and dry lubed.

Mirror re-coating

"Second Light" log entry

Here's the entry from the observing log for 5/6 April 2012:

Location: Apartment G.

It's a great night so far. A bit windy but 50% of the time seeing has to be 4 out of 5. and 25% of the time it approaches 5 out of 5 (bursts that last for ten to 15 seconds every minute or so). I will quibble with the law that says "new equipment == cloudy nights".

Today (5 April), I received my re-coated 8" f7 mirror from Nova Optics. The mirror was ground sometime in the 60s or 70s by parties unknown. The original owner is Jim Roe. Steve Dodds at Nova says it's a Corning mirror and was probably ground commercially. He said it tested to around 1/10th wave.

Reassembly of the scope went very well and collimation was a cinch. The only thing that bothered me was a chip, about 5%, along the edge of the diagonal. The chip is original to the scope and its coating was in the same poor shape as the primary so I had it re-coated also. I blackened the chipped area and hoped it wouldn't hurt the view - much. First light is truly amazing!

Early in the evening (2030), before things settled down, Venus was magnificent at 158x(9mm TMB Planetary) using .6ND and Light yellow filters. (It and the Pleiades were still visible together at 16x in the 4" f4 AstroScan.)

2100. Wind picked up and temperature dropping – now around mid 50s. Seeing is improving rapidly. Transparency is the normal mag 2 light polluted city skies. At 204x (7mm University Optics Ortho), the E star in the trapezium was constantly visible to direct vision and the F star was detectable to averted vision 30% of the time.

2130: Then the folks on the street dropped by for an impromptu star party. Two mothers, a teenage and elementary school daughters and an elementary school age boy. They really liked the views of the Pleiades, Venus and the Moon as well as the stories about how constellations differ from culture to culture and the technical talk about the different objects in the sky. Had to go inside at 2215 to make a call.

2330. Mars shows tremendous detail at 446x (3.2mm TMB Planetary). Four dark areas are visible and have been drawn and await identification. The North polar cap shows as a very small white patch surrounded by darker areas like a thin ring. Made a 5x7 drawing.

0050: Gamma Leonis, a double star at 4" separation, is detectable as two stars at 57x(25mm Astro Tech Paradigm) and at 446x shows a huge "chasm" between each other. I rather suspect this scope will easily split sub arc second stars - on to Porrima: This one is questionable for the moment. Conflicting estimates range from .3 arc seconds separation up to 1.5 arc seconds. It is detectable as a double at 158x and easily separates at 285x(5mm University Optics Ortho). Sure doesn't look sub arc second to me. Maybe one arc second separation.

0200: The Moon is just at 99.5% illumination so the western limb is showing just the thinnest terminator I've seen in a loooong time. This area of the limb just happens to be the libration point so many craters not normally accessible to us are visible tonight. Craters XENOPHANES, GALVANI, PYTHAGORAS, PASCAL, CLEOSTRATUS and many others along the limb are just fantastic at 800x! No kidding, 800x is achieved by using a University Optics 2.8x Klee Barlow and the 5mmUO Ortho! A bit soft but detail is abundant. Best seeing of the night.

0245: Saturn's Cassini division is tack sharp at 285x. The Southern(?) cloud band shows a lighter center I've never seen before! In fact, it looks like there is a second cloud band very close to the pole. The moons Dione(mag 10.4), Tethys(10.2), Rhea(9.7, Iapetus(11.1) and Titan(8.3) are all visible to direct vision at both 158x and 285x. All under mag 2 city skies no less.

Those folks really knew how to make mirrors way back when! it looks like I've finally got a scope where the eyepieces are now the limiting factor!

Ya know, after working with this scope and it's hardware for the last four weeks, I shouldn't be surprised at how good it is optically and mechanically. After all, it was built by some of the finest aerospace workers in the world. It's certainly worth far more than $49.95. Jim was right - I like it!

5 May 2012:

I sent a request to Jim for more information on this scope. Here is his reply:

I'm sorry but I just cant' remember the name of the guy who built it. He was a friend of Paul Westover and didn't belong to the McDonnell Astronomers but I would see him when we met at Paul's (the MAC met at member's homes on a rotating basis in those days). All the folks who might remember him are dead now. I think I paid $250 for it. The RA drive worked in those days.

I used the scope to finish the Messier Club. I remember I got the last one on Christmas night.

I took the scope to the solar eclipse in Nova Scotia in 1972 and got the image that was published in S&T with it. I still believe that this was the largest scope to view that eclipse (everyone else was clouded out).

I got the 17.5 inch Coulter mirror shortly after that and that became my chief observing scope. Mark Jones has now resurrected that mirror into his DOB. He brought it by my house just the other night on his way to Onondaga for the public event there.

Jim

Update

Following successful testing, I gave the pier to SLAS member Bill Davis for modification. Bill is a machinist far beyond master class. The trouble with the pier was it was about six inches too tall. The eyepiece of this scope sits too high when the scope is mounted on the pier.

Bill knocked off six inches from the pier and made two adapters. One for the EQ6 equatorial head and another for a EQ4 equatorial head. The pier was powder coated by SLAS member Steve Sands.

The pier was finished in time for a trip to Albuquerque New Mexico and the 2012 annular solar eclipse followed by the June transit of Venus (Images below).

The combination of the EQ6 and the pier has turned into a real workhorse for all my observing needs. The scope itself is a superb planetary and double star instrument.

(As always, click on an image to view a larger version)

Here's the response from Steve at Nova:

I received your mirror today, and have tested it and found it to be quite good. About 1/10 wave. Also it's not porthole glass, it's a Pyrex mirror from Corning made in the 60's or 70's. I should have it coated this weekend, and shipped on Monday the 2nd.

Steve Dodds

He included a photo of a double pass Ronchi test (on the left).

During a conversation with Steve a few days later, he mentioned that this mirror was typical of the old "Corning pie pan" mirror making process. He says he used to see them quite frequently but not much any more.

He also said he thought it was probably a commercial mirror since the back of the mirror has been ground flat. He said that when the mirrors came out of the mold, the backs were very uneven. Most amateurs didn't take the time to square them up but this one has been ground flat using a diamond grinder.

Initial star testing the night I received it showed pinpoint stars from 56x to 177x. Above that they simply got rounder. The diffraction rings looked textbook perfect. I easily pushed the magnification to 800x and still had a very useable image. I probably could have gotten to 1000x but a .2mm exit pupil is too small for me to use.

Almost a year later (March 2012), I sent the primary and diagonal to Nova Optical for enhanced aluminum, protected coating. Total cost for both primary, diagonal and return shipping was $140.00

2012 Annular eclipse

Using Pentax K20D and an Orion 80mm ED telescope. Filter by Thousand Oaks.

2012 Venus transit

Same setup as the Solar Eclipse above

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