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Appraising a Fine ATM f/23 Mak

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#1 Joe Cepleur

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Posted 06 December 2012 - 05:12 PM

Peter Abrahams's post in another thread may have begun to solve a mystery. My club received a marvelous donation, a home-built f/23 Mak. I promised to provide the donor with an appraisal for her taxes, but have, until now, had no idea where to begin.

The scope is beautifully machined of aluminum. That's the home-built part. This tube is then outfitted with a Unitron focuser, finder, and eyepieces. The optics are not home made. They were manufactured by Three B Optical Company of Gibsonia, Pennsylvania. The included paperwork shows that these optics were purchased in 1964, and were guaranteed to be 1/8 wave or better in mercury light. The maker, although dear to the donor, was surely unknown in ATM circles; this is not a Porter. Obviously, pictures would help.

Still -- are homebuilt scopes generally of little value, even with excellent machining, Unitron parts, and certified optics? Can I safely tell the donor that the scope is worth one- to two-hundred dollars, but no more?

#2 Mirzam

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Posted 06 December 2012 - 05:16 PM

What is the aperture?

JimC

#3 Joe Cepleur

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Posted 06 December 2012 - 05:25 PM

What is the aperture?

JimC


Yes; sorry for the oversight! The documentation states:

4.5" Maksutov primary

4.45" Maksutov corrector

#4 albert1

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Posted 06 December 2012 - 06:35 PM

Have you looked through it yet Joe? Can you post pics?

#5 Joe Cepleur

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Posted 06 December 2012 - 07:45 PM

The paperwork is currently in my possession, but not the scope. I may have pics to post; I'll check. Hate to brag, but... I could not get the scope to focus, so I delivered it to the club's optician, who reports:

"very nice sharp planetary images... it's a gem."

It would be in his nature to have star tested it, but I don't have that report yet, nor do I know how he got it to focus. Not a problem with a draw tube!

#6 mustgobigger

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Posted 06 December 2012 - 08:05 PM

I have a custom made f/20 6"
Mac and had the same focusing
problem.
Turned out the secondary was
Off a little in distance and after
A little adjustment it came onto
Focus.
Great planetary scope....but heavy.
mine also has a unitron focuser
And electric focus control.
I would think mine is worth 500.00
The optics were custom made by
Atm'er.

#7 actionhac

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Posted 06 December 2012 - 08:21 PM

Cave bought cassegrain optics from Three-B.
It may be a great scope.
I recommend a star test.
ATM scopes are marvelous to restore and test, and put into service if the optics are good. I rarely am disappointed. Usually the builder puts his or her all into the project.
A lot of times the builder has some ingenious idea to try out that can't be found commercially. Or just can do it better than anything that can be bought and not satisfied with someone else's workmanship.

Robert

#8 Joe Cepleur

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Posted 07 December 2012 - 07:33 AM

Took a few quick pictures to mail to the club's Vice President of Equipment when we first received the scope. The box is not fine woodworking, but is perfectly custom-fitted and protective.

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#9 Joe Cepleur

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Posted 07 December 2012 - 07:34 AM

It is amazingly beautiful in person, a real shock when one opens the box. Obviously, we'll need better pictures in good light when the scope is back in my possession. Given my impatience to watch Jupiter rise over the lake through it, perhaps that will be soon!

The scope was a gift from the builder's widow. She originally inquired about selling it, but upon seeing the wild excitement it inspired in our club, she donated it instead. Her husband had loved this scope into being, so she enjoyed knowing it would continue to receive devoted appreciation.

Still, it must have a value for her taxes. What might I tell her it is worth?

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#10 Joe Cepleur

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Posted 08 December 2012 - 10:02 AM

This thread began with the notion that an ATM scope would never bring more than $200 at auction, but now adds a knowledgable collecter's opinion that an ATM in his collection is worth $500. Can anyone report on verified prices paid for ATMs at auction? I, and the donor of my club's new ATM Mak, would be grateful for your help.

#11 John Jarosz

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Posted 08 December 2012 - 10:18 AM

Antiques are worth what someone would pay to buy them. Appraisers use data from prior sales of identical or similar items to arrive at their 'best guess estimate' of what they THINK someone would pay for an item. The value could change significantly if there were two people attempting to buy the same unique item.

Finding one person with a scope that he says is worth $500 doesn't necessarily change the value of all the other scopes out there. If he tries to sell his scope at $500 and no one buys it, then it's not worth $500.

The trickiest thing to appraise are items that are unique, where there are no other examples of the same item.

John

#12 mustgobigger

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Posted 08 December 2012 - 10:43 AM

Thing is...you have known components ..
Looks like a unitron finder and rings.
That's $100.00
Unitron focuser $100.00
And a possible cave quality mirror
And secondary if it tests good
Should bring another $100.00
So you can safely say at least
$300.00 and that's low side.
Even if you have no intention
Of splitting it up.
Just my opinion.

#13 Mirzam

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Posted 08 December 2012 - 11:16 AM

If someone from the astronomy club could characterize the mechanical and optical performance, and if a money back guarantee was offered, I think it would be pretty compelling at $500 if the performance is excellent.

JimC

#14 Joe Cepleur

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Posted 08 December 2012 - 05:32 PM

These are helpful posts, thank you. Yes; every component that the maker did not machine himself is Unitron, including two eyepieces not yet accounted for in the $300 minimum value as parts. With them, it's worth $350 to $400. I'll star test it when it's back in my hands. I know how to tell if it tests well, and can ask about significant aberrations if I find them. 

It's looking as though I could tell the donor the scope is worth a minimum of $400 due to the quality of its commercially produced components, and (assuming a suitable star test) an estimated $500 as a complete telescope. To the club, it's priceless. We love scopes with provenance and fine optics! 

#15 *skyguy*

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Posted 08 December 2012 - 05:59 PM

Any appraiser would certainly look at the price of a similar new scope ... the Orion 127mm (5") Makustov is priced at $400. It has no historical value since it was built by an unknown amateur using commercial optics. However, it is interesting to note that the Three B Optical Company supplied Schmidt optics for the Lunar Surface Ultraviolet Camera on Apollo 16.

With the build quality and included accessories, I don't think a tax auditor would raise an eyebrow with an appraised value of between $500-$700. Since appraised values are usually set notoriously high, I'd go with the higher figure.

#16 Da Bear

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Posted 10 December 2012 - 01:06 AM

I have consulted (at NO fee to keep things honest) on many, many optical instruments appraisals and most of the comments in this thread are generally true. However, appraisers do not “set notoriously high prices” without some documentation to back up their work product, otherwise they would not be in the business very long.

ATM scopes require more homework to appraise, but aperture is aperture, glass is glass, and so forth. Workmanship and the image quality of ATM hardware are sometimes given additional consideration than in assessing the value of mass-market scopes. Provenance is a prime consideration in all appraisals, but especially in ATM scopes.

There are also so many subjective values that may be placed on any object. Sentimental value vs. insurance replacement value can be a difficult choice.

For important items get an ASA (American Society of Appraisers) member to write your appraisal. They cost a bit more, but insurance companies almost never contest their valuations.

Da Bear

#17 Joe Cepleur

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Posted 10 December 2012 - 09:17 AM

The club's goal is to provide the donor with a fair appraisal that will minimize her taxes, while not unduly raising the book value of our collections. I, somewhat naively, accepted the role of appraiser, and must say that appraising the ATM is a far cry from other appraisals I've done. With commercial scopes, I cruise eBay and Astromart to find the going value. It's not so simple in this case, but I love learning, so no complaints.

Comparing this scope to a new 5" Orion Mak is smart, yet they are not quite the same beast, because the same beast has likely not been manufactured in decades. The Orion is f/12.1, about half the ATM's f/23. The ATM is from a period before modern ED glass. Beginning sometime in the 1950s, there was a movement of ATMers building Maksutovs. The design sought to combine the perfect color correction of mirrors with the smallest possible obstruction to make a 4" planetary scope of small field of view, but with images rivaling the finest, most expensive 4" refractors or 10" off-axis reflectors (10" stopped down by 4" mask). The low mass and short tube required only a lightweight mount (compare the weight of a 10" Cave Newtonian!), and the simpler eyepieces of the day were better at f/23. This was a connoisseur's scope, a low-budget, magically low-weight rival to the best views otherwise obtainable in the era.

The scope is clearly more valuable to the club than its insurance value would suggest. Donations are priceless. Pay nothing; get something. For a club with roots in ATM and observing (others in our region emphasize dinner parties and speakers), this particular scope is an exceptional gift. Four inches of glass may not seem like much, but I could easily carry this scope outside as a grab-and-go for spectacular views of Jupiter as it rises over the lake. Last month, our club poured a ton of concrete for a pier for a 14" Meade Schmidt-Cassegrain at one of our outreach sites, but that beast requires two strong men just to lift onto its mount. Different scopes for different purposes!

#18 *skyguy*

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Posted 11 December 2012 - 12:09 PM

However, appraisers do not “set notoriously high prices” without some documentation to back up their work product, otherwise they would not be in the business very long.


The use of term "notoriously high" was not intended to imply "overvalued" but at the high end of the estimated value ... the highest price realized, sold under the best circumstances. However, my past experiences with appraisals on antique jewelry, antique firearms, antique cars and commercial properties ... show that the actual sale price in an open market can be significantly lower than the appraised value ... especially if your looking for a quick sale.

#19 Joe Cepleur

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Posted 04 February 2013 - 08:37 AM

An update on this telescope, instructive for some, a laugh for others:

Neither my club's treasurer or I could get this scope to focus, yet our optician focused it immediately and reported it has excellent optics. What's his magic?

It turns out that baffling a Maksutov is complicated at best, and not worth the effort at worst, especially for a home-built astronomical scope. The treasurer and I had each tried to focus the scope on a distant object during the day, when the extreme glare from the blackened, but un-baffled, tube obliterates the image. The optician tested the scope at night when, without the glare, it works fine, yet with a twist. Focusing on stars is no problem. Bright objects such as Jupiter are obscured with glare until they are exactly centered in the field, whereupon they suddenly snap to focus!

#20 DrewFamily

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Posted 04 February 2013 - 10:37 AM

Not sure if you'd be interested in publicing naming the ATM, but I'm sure I'm not the only one who is curious to hear who built it. Jay in CT

#21 highertheflyer

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Posted 04 February 2013 - 03:04 PM

I know in the new political environment, and of a value by one or two appraisals, may not survive the tasks of US IRS regulations.
I continuously worry about the deductions of classic scopes towards 501'c'3.
I know of an 8 inch Meade that will sell for peanuts, as of yours and mine, and with the burial of old tube television cases in landfills, we might see them only packed together in a big glob..
Such a waste. Jim

#22 JohnH

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Posted 05 February 2013 - 11:11 AM

An update on this telescope, instructive for some, a laugh for others:

Neither my club's treasurer or I could get this scope to focus, yet our optician focused it immediately and reported it has excellent optics. What's his magic?

It turns out that baffling a Maksutov is complicated at best, and not worth the effort at worst, especially for a home-built astronomical scope. The treasurer and I had each tried to focus the scope on a distant object during the day, when the extreme glare from the blackened, but un-baffled, tube obliterates the image. The optician tested the scope at night when, without the glare, it works fine, yet with a twist. Focusing on stars is no problem. Bright objects such as Jupiter are obscured with glare until they are exactly centered in the field, whereupon they suddenly snap to focus!


Maksutov/Cassegrains have the limits that all Cassegrains have: Sky-Flooding.

What it means is without proper baffles, light from the sky has an UNIMPEDED path through the telescope, into the eyepiece. Resulting in degraded visibility when bright objects shine in.

The photograph below is a disassembled Ad Astra III Maksutov I bought a few years back.

When I first used it, I found it excellent for its size under dark skies but rather poor on Jupiter and the Moon.

In broad daylight, even worse. Going through the items in the case, I found the conical baffle for the corrector spot there. Once glued back on, performance improved.

I would say it would be worthwhile to baffle the scope properly. With Maksutovs, the baffles are calculated in several steps. In the end the are a compromise: Larger baffles mean darker fields but a larger obstruction.


ATM telescopes are in the eye of the beholder, and a bit of research would help. The f/23 ratio is similar to a design the late John Gregory published in '56 or '57. It was for a 6" instrument, but if scaled down, it would retain the same ratio

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#23 Joe Cepleur

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Posted 05 February 2013 - 01:06 PM

Thanks, John... "Sky-flooding." Never heard the term before, but, yup! As soon as I read, it, I thought, "That's exactly what's happening." Great explanation. Fascinating that the glare from off-center or day-lit objects is so severe as not to just hurt contrast, but completely obliterate the image!

I discussed baffling with our club's optician. This is likely a matter of taste. His feeling was that baffles are difficult to install and unnecessary for this scope to be used in the dark, so long as one is careful to center objects exactly. His logic nevertheless fits with yours. He says that any baffle would necessarily enlarge the obstruction, by fitting around the outside of the secondary. This would work against the idea of an f/23 Mak, which is to have the smallest possible obstruction for the most refractor-like image. It must depend upon the intended use of one's Mak. Given the other scope in the builder's collection, an 8" Meade 2080 SCT with silvered optics, I'm guessing the Mak was reserved for planets and double stars.

Ad Astra has retired, and is selling off his old stock on eBay. Great seller. 100% honest, accurate descriptions and five-star integrity. I have managed to win a few items, including a magnificent vintage University Optics orange finder to match my orange tube C8!

#24 DAVIDG

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Posted 05 February 2013 - 01:58 PM

Does the scope have any baffles at all ?

- Dave

#25 Joe Cepleur

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Posted 05 February 2013 - 02:34 PM

Does the scope have any baffles at all?


It's not currently in my possession to inspect, but as I recall, no. But, it is well blackened.






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