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Classic scope: Optical Craftsmen 6" Newt
Discuss this article in our forums
Optical Craftsmen "Connoisseur" 6-inch f/8 Newtonian
Old scope, new beginnings
Back in September of this year I posted to the CN forums about a vintage scope I had recently acquired; What follows is a recap, and an expansion of the story regarding my "new old scope".
A longtime friend gave to me his Dad's old telescope, which had survived
as a tube (aka OTA) only, the steel pedestal & mount having long since converted
to rust. The scope had been purchased "new"- obtained by his Dad
with much patience, research, and $$ while teaching science in a San Jose
CA area high school back in the '60s. His Dad has long since passed on, &
the scope has been rolling around in garages (including my own for a while
back in the '90s), never used.
My friend not being into astronomy, but knowing his Dad would have wanted the scope to be used & enjoyed, passed it to me (again). However this time around i felt a bit differently, having since learned quite a bit more about astro-equipment, and was now actually excited about getting the thing into service. Here's why- this scope is potentially a VERY nice rig:
* 6 inch F8 Newtonian
* made in the early-to-mid '60s
* silver & black label up by focuser reads "The Optical Craftsmen - Northridge California"
* four-vane, four-screw, fully adjustable spider
* 1-1/8" secondary (~19% C.O.)
* extra-long tube, extends forward of focuser
* beautiful enamel-white tube, fully flocked!, mil-aluminum end rings
* nicely designed open alum. rear cell, three spring-tensioned finger-adustable screws, three screwdriver thrust-only screws
* only potential mechanical "imperfections" are a miserable rack & pinion focuser, & that the tube I.D. is only 7"... perhaps not quite as optimal for thermal venting
Note: The following pix are after its thorough cleaning
Back in the '90s when this first passed into my possession i owned a very decent Meade 826c (8" F6) Newt, so saw little need for fiddling with this "old" scope... but now i recognize this little old grandpa scope was designed & optimized to be what we might term a "planet-killer"... & if it's optics were decent, might stalk to kill yet again!
Relic, or Relish?
Posting the above description to the CN forums, I inquired as to the history & reputation of this line of scopes, trying to determine if the cost of the many upgrades necessary would be justified. Considering the dirty condition it was in, its lack of a mount, and its vintage- I wasn't sure whether to salute it, wheelchair it, burry it, museum it, or use it to put my SCT to shame! However, many of you responded very positively- having actually owned, used, and ENJOYED them yourself! Apparently they had a reputation for putting a lot of effort into their optics. One CNer, Jim, even stated " Listed in both the 2nd & 3rd editions of Phillip Harrington's book, STAR WARE, the "Optical Craftsmen "Connoisseur" 6-inch f/8 Newtonian reflector or larger" was listed as one of the ten Best Telescopes of Yesteryear. If you find out that your model is the Connoisseur model, consider yourself one very lucky guy." I suspected I might be at that!
The encouragement was enough for me to, at the very least, undertake a cleaning
campaign no small task considering how grungy this beast was! This would
entail evicting the spiders (decades of being stored uncapped!), removing
& cleaning the mirror(s) (thru the dust & spider poop the coatings *looked*
okay), thoroughly vacuuming/cleaning the tube (maybe even hosing, hoping the
flocking doesn't come loose!), & lubing the R&P focuser (pretty marginal quality,
considering what's currently available).
The primary mirror & cell were removed & soaked in the kitchen sink after about an hour I gingerly attempted to nudge one bug spot. No luck. It had taken up permanent residence for years, & would require more heroic efforts. I momentarily eyed my Binford 5000 rotohammer, but instead reached for my wife's largest Tupperware. A marinating sauce of dishwash soap & 72 hours (a nudge-test at 24 hours still failed), along with the requisite sterile cotton, distilled-water, and 99% isopropyl alcohol proved equal to the task. However... many bug-spots never lifted out 100%, leaving behind small pin-head size marks. Plus, the outer 1/4" of mirror for a good part of the circumference was lightly blemished- almost like a TDE mask had been applied at one point. And there were some hairline scratches... maybe my cleaning, maybe old. I thot "it will *work* for now", but i knew I'd eventually want to have it recoated.
The secondary was about the same... a few spots that didn't 100% lift out, plus a general wax-paperish haze to the mirror- wasn't evident with a bright white LED light shining directly in it, but was quite visible when viewed with the light off-axis. Again, it'll *work*... but the optics were NOT at their best... and i wasn't experienced enough to ascertain at what percentage they were likely performing compared to being fully recoated. Mirrors & SCT correctors are funny like that... they can look like trash & still give a decent view.
The 72 hour period of optics-marination gave me the opportunity to work on the tube itself. The inside cleaned up pretty well with a leaf-blower to remove the chunky stuff, followed by a vacuum cleaner angle-brush-and-wand assembly, combined with my arm's reach. The felt flocking seemed fairly resilient, and hosing turned out to be happily unnecessary. The tube exterior was cleaned up using my McGuires Automotive polish, nearly all the scuffs & blemishes polishing out to an extremely beautiful & silky finish. This sucker was now clean as a whistle, slippery as an eel, & white as a ghost!
Even the old "Edmund Scientific Co." finderscope (measured at 32mm?) cleaned up pretty well, and actually functioned decently! The objective was deep-set into the metal tube about 1-1/2", the tube itself being a dewshield. However, the tube interior was exposed, shiny metal- if pointed anywhere near a light-source, you'd get a chromatic lightshow! Later on, a little adhesive flocking lining the "dewshield" area yielded very positive results.
The focuser? Well, I did what I could but it was a nasty bugger when new, & age hadn't improved things one bit! The "rack" was more akin to the device used in medieval times for torture even cleaned & lubed, the "pinion" still had a tough time of it- the torque required to focus constantly threatening to strip & override the set-screws at the plastic knobs!
Finally pulling all the pieces back together, I was quite eager to get this
rig out under the stars! Unfortunately, the subject of mounting which had
been to this point so cleverly ignored, came to the forefront: All I had available
was an EQ2 with hollow aluminum legs. Orion rates its capacity at 10 lbs.
max, & the scope attempting to be installed weighs ~12 lbs and is nearly four-feet
long plus I had no rings to fit! Desperation has been known to drive men to
insane measures so with a little searching I came up with some bungie cords.
Cradled with a pillowcase for coosh, & bungied onto the EQ2, this arrangement
was actually sufficient to give me the opportunity to view
Wow! Unbelievable views! This scope seemed to my non-expert eyes to have seriously nice optics! Even with the aforementioned blemishes, even with one stripped adjustment screw on the secondary & a resultant slight miscollimation, and even with a nasty, crotchety old R&P focuser- i was treated to some very sharp, contrasty views of the first-quarter moon.
You know how it is when you focus?- the image grows less fuzzy until it suddenly begins growing *more* fuzzy again, & you see-saw back & forth 'til you get that least fuzzy spot called "perfect focus". Well, okay... that's a typical higher-magnification scenario, but how you often wish that image would just keep getting sharper & crisper? Well, this scope's got what they call "snap" to its focus- and when you dial it in, it doesn't disappoint! Yes, i could detect some of the secondary's blemishes- kinda like the effect of a "floater" in your eye that won't blink away. But seeing past it to the moon itself, i was having riveting views along the terminator! From a 15mm wide angle EP, to a barlowed 9mm LVL at 260x, i was cruisin'... finally settling on a barlowed 15mm LVL at 156x for savoring some extra-crispy lunar topography. Sweet!
My hopes, and the encouragement of those who had used these scopes, were confirmed! This was indeed a fine scope, deserving of those needful upgrades. She was a grand lady, as stated by one CNer and it was then that a fitting name came into clear focus "LadyScope"! And the main thing she needed now was a new ride
Ascending the Mount
My understanding wife (the one with the now-buggified Tupperware!), and I,
together took Ladyscope for a drive to the coast, intending to take her mount-shopping.
Orion Telescopes being so near, it's amazing they see so little of me. Tsk.
Ladyscope & I had our eye on the EQ3 as a potential solution, but upon inspecting
other scopes on the showroom floor so mounted, it was apparent that this mount
is less than ideal even the salesperson admitted they had an undefeatable
wobble in the RA axis- no amount of knob tightening would banish! It's no
coincidence that Orion markets their own 6" F8 "Long-Tube" Newtonian on the "SVP" mount. There really wasn't much of a choice
but at $400 complete with mounting rings & an RA drive, the choice was quite
bearable. And I knew I'd regret every session having chosen anything less-
the mount is just not a place you'd want to skimp, especially for only a hundred
Once home, assembly was straight-forward & fairly quick, so that evening we were under the stars! This is a very solid mount, no slop or play when the axes are *locked*, its not moving one whit. Vibrations dampen very quickly, even for a longish OTA, and as I was about to discover, the SVP mount would enable steady viewing at very high magnifications! It was at this point the story left off in the forums.
Equipped now with a suitable mount, and her optics being cleaned of the grime
of decades yielding reflective surfaces that were *functional* (but really
begging for a new coat), LadyScope has blessed me with splendid viewing
of Lunar & deep-sky objects... with a winsome smile, yet total class, she
gives me 1.4 degree wide vistas with pin-point stars in a 24mm Pan, while
my faithful friend, the FOV-challenged 10" SCT sits sulking in his storage
cabinet! This shouldn't have come as any surprise, but still... it is so very
sweet. Yeah, sure- i'm giving up four HUGE inches of optical horsepower,
& my DSO faves aren't quite as bright as i'm accustomed to seeing...
but those tight stars, and that w - i - d - e field... so this is what you APO people are seeing, eh?
Being now the primary guy in LadyScope's life, i have begged her lenience & favor in postponing the shopping trip for a new coat, preferring instead to focus on the mechanicals. She seems quite understanding, taking to her new Orion SVP mount with grace, happy to shed the sorry bungies of the sad-sack EQ2 that had been her ride. The honest truth is, with the wonderful views of Mars, the Moon, double stars, & brighter nebula... and those now stabilized on an excellent mount- i'm more than a little reluctant to "fix" that which doesn't seem very "broken" at all! Especially since that would involve removing mirrors & shipping them off to a total stranger's vacuum chamber, relegating her to "standby" status just as Mars slides into prominence in our evening skies. No, not a happy choice at all...
Retiring the Gnome!
So instead, LadyScope & i have continued along the lines of mechanical upgrades,
while enjoying our nighttimes under the stars. Turning attention to the stone-age
R&P focuser that she had come with- Yes, the crotchety old gnome that had
hobbled her performance from day one, transforming the fingers of her viewing
partners into gnarled, arthritic stumps... it was time to hit the road! Someone
here at CN had suggested the 2" Crayford units carried by DBA- whoever you
are, you have our sincere gratitude!
Phoning Dale at DBA, we discussed the in's & out's of such an upgrade, his enthusiasm & encouragement being much needed, 'cuz just the thought of drilling focuser mounting-holes in my beloved Ladyscope had been paralyzing me to inaction. Plus the focuser drawtube... might i need to widen *that* hole as well? Yikes! Dale's approach was wise & methodical- measure every EP to be used with LadyScope at its focus position off the exterior of the tube, solo & barlowed, in the existing gnome-focuser. The resulting matrix revealed a very pleasant truth... none of my EPs currently required the existing focuser drawtube to extend down thru the scope's tube! In fact, the focus position hardly varied from one end of the EP stable to the other, barlow or not. And happily, that range could be nicely accommodated by the DBA unit with the addition of only four small bolt holes!
So Dale sent along one of these Crayford beauties, plus a Newt fan-kit, as well as his words of wisdom for their implementation. Using a borrowed Orion 'deluxe' Laser-collimator, i made sure the existing optical train was aligned, then removed the old gnome from his prominent perch! LadyScope seemed to sigh with relief as the crusty curmudgeon of a focuser was lifted from her lovely white neck, to be replaced with the new DBA unit & duct tape to temporarily hold its position. This DBA Crayford unit is a 2" job... big, black, and beautiful, with a curved base & silky-smooth motions... a very refined piece of equipment. Did i mention it was big?... 'twas designed for a 10-12" scope, i believe. Laser ablaze in the new focuser, the unit was scootched around until it was perfectly receiving the laser's return beam, its position carefully & securely taped in place. Then double-checking the drawtube's relation to the existing tube hole, the laser alignment procedure was repeated again & again until i was convinced well beyond my nervousness that the new focuser's position was spot-on. No more than FOUR new holes would be permitted in LadyScope... or i die!
Marking down thru the thick focuser base with a bent paper-clip, circular scratchings in the white paint were etched for hole-drilling purposes, then marked with ink for better clarity before drilling. After applying a patch of black ScopeStuff flocking to the tube area beneath the new focuser- didn't want any reflected light coming off the scope's white tube & up into the drawtube- i began with the finest bit in my kit; Four pilot holes were drilled. Back comes the focuser & laser to make quadruple-certain all is aligned as it should be. Ha- i'm not nervous! Satisfied, a larger bit is chucked, & the holes are widened. A third bit brings them to barely pass the new bolts. With such tight holes, there's no room for error... this focuser will now fit, or it won't. It of course didn't! But only by a tiny smidgeon, so after carefully massaging the fourth hole with the drill to elongate it a skosh, all went together. Giddy with relief, i then resumed breathing.
Turns out the tube was NOT aluminum as i'd guessed, but rather some kind of fiberglass affair... the residue from drilling wasn't curly shards, but white flecks & powdery stuff. And yes, the secondary had been covered with an old plastic pill bottle for protection from the debris. Once finished, all residue was wiped, brushed, and vacuumed away. LadyScope was now fully ready for action... needing only a little flat-black rustoleum touch-up on all of the shiny metal fasteners exposed inside her OTA. But that would wait, 'cuz i was eager to focus on the fruits of my efforts!
Mounting LadyScope in the SVP cradle, i proceeded to rig a make-shift velcro strapping assembly to support the new fan to blow onto the back of the primary mirror. Like a kid with a new toy, i'd hardly got the fan running when in went a 24 Pan EP & Ladyscope was pointed skyward. Ahhhh, yes... focusing was now a joy; precise & crisp stars were a gentle roll of the finger in coming! The Moon was being a DSO spoil-sport, & Mars was now above the trees... so out comes the Pan & in goes the ol' 15mm LVL. Mars is very bright... and still very small... so swapping in my 1970's Edscorp 12.5mm Ortho, it is just as quickly replaced with my current high-power EP- the beloved 9mm LVL. Now, in a scope with focal length coming out its ears like my 10" SCT, 280x would pretty much be the end of the line for magnification for 'normal' observing... but yielding only 130x with LadyScope, there was room to go... except i'm outta EPs! So out comes the 2x Ultima barlow & the Ortho for 187x... about 30x per inch. Now Mars is starting to look like something, with some detail being revealed fairly clearly. Still, it's agonizingly small in image scale... and my only other EP option is gonna be the 9mm LVL barlowed! 260x has gotta be pushing things, at 43x per inch... but nonetheless worth a try. Amazingly, Ladyscope handles this magnification without even straining- yea, asking for yet more! This is unreal! Remember Mike, these mirrors still need recoating, the primary still having nasty stains of the bug-spots that only mostly came off, and the secondary still has a full third of it's surface marred with a kind of wax-paperish gauzy haze. Yet i go on to enjoy some stunning views of Mars, the scalloped edges of, i believe, Mare Cimmerium in moments of good seeing in stark relief! And to think she wants more power! Could this be possible?... or am i just getting my imagination sucked into an optical delusion?
Probing the Depths
Hmmm... perhaps this is what all the hoopla over short FL EPs is all about...
many scopes not having thousands of mm's of FL to throw at an image. Looks
like I'll need some reinforcements to get to the bottom of Ladyscope's magnification
well! The only thing that makes any sense to me at this point is another barlow,
high quality, maybe 2.8x or 3x... or a 'Powermate'. Running numbers, the logical
choice is Televue's 3x barlow- the 2.5x & 2.8x options yielding too many duplications
amongst my current EPs. Unfortunately, my favorite 9mm LVL would then be clocking
at 389x... but my other EPs would scatter nicely down the chart at 280x, 234x,
& 206x- all very useful slots.
So after a modest $100 investment and a short wait for the beloved UPS guy, we're back in the yard, EPs at the ready, barlows quivered... me & LadyScope are gonna shoot ol' Aries! Running up thru the arsenal of EPs, we top out at the 9mm LVL barlowed to 260x. Yup, still looks bright & crisp, there does seem to be room to go- no anomalies here. Out comes the 2x Ultima, in goes the TV 3x with the 12.5mm Ortho in its embrace. I can almost feel Ladyscope's gentle laugh as the 280x image comes into focus... still sharp, clear... and even at 47x per inch, decidedly BRIGHT! What in the world is going on here? I'm near about going in to check the batteries on my calculator, wondering where i've goofed up in my calculations... when she seemingly whispers in my ear: "let's go a little wild tonight!"
But hold on- the "experience" hadn't even been fully experienced yet... i
decided to play with my new DBA cooling-fan! It was suspended centered behind
& blowing upon the primary mirror using velcro tabs stuck to four rubber straps
cut from an old bicycle innertube & fastened to velcro mates on the rear of
the tube. With Mars happily floating around in my LVL eyepiece, magically
suspended there by the single-axis drive motor on the SVP mount, i proceeded
with impish enthusiasm to unplug the fan from the field-battery. Hopping quickly
back to the EP, i was able to observe the image begin to mush to only about
80% of it's former clarity, over the span of 10 to 15 seconds. I continued
observing in this manner for several minutes, swapping EPs up & down a couple
of times trying to find a new *sweet-spot* where the image cleared & sharpened
To ensure that what i'd just observed was due to the halting of the fan-induced air current up the OTA and not some random atmospheric event, i re-engaged the "cooling" fan. Jumping back to the EP, i observed the image of Mars continue as semi-mushy... then begin to wobble & jostle about... then suddenly settle into the clear, steady image i'd been drinking in a short while ago! There wasn't much question remaining- this fan was definitely contributing significantly to the images this scope was putting up! Holding my hand up to partially cover the front-end of the scope, a gentle breeze could easily be felt, obviously originating from the the fan blowing onto the backside of the primary mirror at the "bottom" of the tube. It surprised me a bit- that this volume of air would somehow find it's way around the edges of the mirror & all the way up the tube with any perceptible velocity remaining... but it does... i suppose a simple matter of *pressure*. And it's enough to make a very noticeable impact on the image produced by an optical system that traverses that air nearly 2-1/2 times before arriving at your favorite eyepiece! I've read about such things... and now i've *seen* it with my own eyes. I'm a believer! And "cooling" fan is a bit of a misnomer; Perhaps "TACS fan" is a better fit for this arrangement (tube-air-current-stabilizing)?
As thrilled as i may be over Ladyscope's obvious optical prowess, it would
be my semi-educated guess that a properly installed, quality, rear-TACS-fan
would contribute more to the resultant images produced by any optically
*decent* Newtonian telescope than hot-rod optics could produce alone.
I'll go one further & state that a good, solid mount may be equally important,
with very similar *optical* contributions deriving there from. These mechanical
measures being present would then free up any optical system to perform
nearer its true potential.
I suppose some kind of "follow-up" may be in order, as eventually the subject of mirror recoating will work its way to the front. Once performed, will they produce any evident changes to Ladyscope's images? Perhaps some limiting-magnitude evaluations before-and-after would be telling? Could be difficult to quantify... & "gut-feelings" over planetary images could certainly be subjective. Still... as buggered-up as the current coatings are, it sure seems like there would have to be some improvement! Right?
Finally, to the creators of "Optical Craftsmen" Newtonian telescopes of the 1960's, with their flocked tubes, quality mechanicals, & apparently excellent optical components, i give my hearty thanks & appreciation! You know who you are... you had a lot to do with the high quality of this fine hobby back then, to many happy memories shared between Dads & their kids of two generations passed; Your efforts are now combined with those of quality upgrades from today's conscientious manufacturers- together engaged in rewarding a *third* generation of stargazers with spectacular views of the heavens.