Dmitri Dmitriyevich Maksutov was born in Nikolayev, Russia, on
April 11, 1896. He expressed an interest in astronomy at an
early age and at age fifteen he made a telescope with
an18-centimeter mirror. Some time late he made an improved
21-cm reflector and made such extensive astronomical observations
that they attracted the attention of the Russian Astronomical
Society to which he was elected member at the age of fifteen.
In 1913 he enrolled in the Military Engineering College in St.
Petersburg, but in the following year classes were cancelled and he
saw several years of military service in World War I and the Russian
Revolution before he could return to his interest in optics.
During the 1920s and 1930s Maksutov first worked at the State
Optical Institute in St. Petersburg, then the Odessa Observatory,
the Odessa State Physical Institute, and finally back at the State
Optical Institute.
But it was not until August, 1941 that he invented the class of
telescopes for which he is most famous and the one that bears his
name. It was patented in the U.S.S.R. according to the claim
dated November 3, 19411. He discovered that a steeply
curved meniscus lens in front of a spherical mirror could be made to
introduce the correct amount of over corrected spherical aberration
to balance the under corrected spherical aberration of the mirror.
Even more remarkable, the single corrector lens could be made nearly
achromatic with far less residual color than an equivalent achromat,
and the entire telescope could be made coma free, with very small
residual astigmatism. This concept of a single meniscus lens
is so powerful that it may be applied to many types of telescopes;
the Newtonian, Cassegrain, Gregorian, Mersenne, Schmidt, and even
the subdiameter Ross-type corrector. The optical world first
became aware of this exciting new type of telescope in Maksutov's
paper published in the Journal of the Optical Society of America in
May, 1944, "New Catadioptric Meniscus Systems," from which the
following quotes are taken.
The high universality of the new systems assures their
successful use in almost every branch of optical instrument
making (geodesic, photographic, spectral, laboratory
instruments, microscopes, and so on). However, this paper
is written with the interests of astronomers in mind and will
afford them the possibility of designing and making new
instruments for amateur observations as well as for scientific
ones. The present paper gives only the principal results,
without theoretical derivations and details of design.
The principal role of the meniscus is the correction of
spherical aberration and coma of spherical mirrors, without
introducing a noticeable chromatism; however, in addition to
that, the meniscus fulfills two very important functions.
Firstly, it shuts the tube and makes possible a sealed
instrument, free from convection streams, with mirrors well
protected from dust, damage, and the influence of abrupt changes
of temperature; secondly, the meniscus makes possible the
fastening to it of secondary mirrors without supports, and often
also without settings by means of an adhesive or by optical
contact; in the most special case the central part of the inner
surface of the meniscus may be aluminized and plays the role of
a secondary mirror, the screening and the diffraction hindrances
being in that case very small.1
In the present age of personal computers and optical design
software capable of high-speed optimization and evaluation, it is
difficult to imagine the countless hours of tedium facing the
optical designer in Maksutov's day. To work out an
understanding of this new family of telescope designs in the
shortest amount of time he was required to trigonometrically trace
the fewest possible rays that would reveal the performance of any
particular design, then repeat the process, without errors, for as
many variations as were being thought up. The only tools were
logarithms and slide rules and it took several minutes to trace a
single ray through several surfaces of a telescope.
Fortunately for the amateur, Maksutov's goal was to find designs
simple enough to be produced cheaply in large numbers, meaning
designs that required all spherical surfaces. These he found
and in his paper he gave empirical formulae and tables that allowed
one to select a particular design dependent upon the desired
aperture. Surprisingly, he showed that visual telescopes could
be designed corrected for spherical aberration, coma, and well
achromatized, and have very low F/numbers. For example, for an
aperture of 19.2 cm a telescope could be as fast as F/3.0.
Maksutov must have had access to western publications, for he
recommended for his Herschelian version of the meniscus corrector
telescope a "Springfield" type of mounting. He died in 1964.
Maksutov was not alone in inventing the meniscus
corrector-spherical mirror telescope. During World War II
other Europeans came up with the same idea, Albert Bouwers in the
Netherlands, Karl Penning in Germany and Dennis Gabor in
England. Bouwers finally published a small book, "Achievements
In Optics," in 1950 describing his version of the meniscus corrector
design for which he applied for a Netherland Patent on October 14,
1940. His Author's Preface begins:2
This monograph intends to give a survey of work on optics in
the Netherlands during the last war or immediately before.
Part of the results mentioned have already been published, but
they have not of course penetrated into the English speaking
countries. However, part of the work referred to was
carried out secretly and the achievements were purposely not
disclosed during the German occupation. The text was
prepared and ready for printing before the liberation of our low
countries. Owing to some purely technical reasons however,
the appearance had to be postponed till about a year afterwards.
So some papers on similar subjects as covered in this volume
have not been paid attention to. Especially the article by
Maksutov in the Journal of the Optical Society of America in May
1944 should have been referred to, since this author apparently
obtained -- at a later date than the author of the present
volume -- many of the results mentioned in the first chapters.
Remarkably, Bouwer's first experiments, done in August, 1940,
were carried out with commercial meniscus spectacle glasses bought
at an optician's. One was used as the corrector lens and the
concave surface of the other was aluminized for the mirror.
The arrangement worked nearly as fast as F/1, yet a photograph of a
woman he showed is one to impress even the casual reader.
Unlike Maksutov who developed his designs empirically from
laborious calculations, Bouwers worked through the paraxial
equations governing how to balance the spherical aberration of a
spherical mirror with a weak meniscus lens. Then he showed how
the aperture stop could be moved to end up with a concentric system,
one where the centers of curvature of the lens surfaces and the
mirror are at the same point at the center of the stop. This
eliminated coma, astigmatism, distortion, and lateral color since
there was now no optical axis. This is a beautiful and simple
concept, one characterized by only four parameters; the three radii
of the concentric surfaces and the index of refraction of the lens.
Bouwers had a flare for revealing hidden beauty in an optical
design, perhaps only appreciated by an optical designer. One
example was to point out in a drawing that the two principle planes
of a concentric lens lie together in the plane of the center of
curvature.
The primary detriment to the concentric meniscus-lens-mirror
combination is that it has a small amount of chromatic aberration,
yet this may be corrected by the single meniscus lens if it is
adjusted to deviate somewhat from concentricity. The second
method of achromatizing the meniscus lens is to split it with a flat
surface that is "buried," meaning the glasses on both sides have the
same nominal index but different dispersions. This is
the method he used to construct a small 22x60 monocular fieldglass.
Finally he presented his corrected concentric system that had a
Schmidt aspheric corrector plate at the center of curvature of the
concentric meniscus lens mirror combination. Only this time
the aspheric corrector plate was very weak, its only role being to
correct the slight higher order spherical aberration of the meniscus
lens mirror combination.
Bouwers did not seem to have in mind the amateur interested in
telescope systems; all the above theory was developed for the single
mirror that is really a camera like the Schmidt system with its
inaccessible and curved image surface. Finally, in a later
chapter he presented a design, without specifications, for a
Cassegrainian type astronomical telescope with the secondary mirror
formed by an aluminized spot on the last surface of the meniscus
lens. One important feature of his new type of telescope was
the use of internal stops to completely eliminate unwanted stray
light from reaching the image surface, something that Maksutov never
mentioned even though he did mention the need for an external stop
at the exit pupil of an astronomical eyepiece or an internal stop
with a terrestrial eyepiece.
Lastly, Bouwers pointed out that the meniscus lens could be
flipped over and placed on either side of the aperture stop and
achieve the same correction. This led to the possibility of a
Gregorian type telescope with its erect image for terrestrial use.
It did not take long for Albert Ingalls to hear about Maksutov's
new telescope from advanced amateurs who had access to Maksutov's
paper in JOSA. In the October, 1944 Telescoptics Department of
Scientific American he reacted by enlisting amateur Norbert J.
Schell, of Beaver Falls, PA, to study the design and report in the
clearest possible manner to the amateur community the details of the
exciting new telescope. By this time he had even found time to
locate a source for lens blanks and got ten advanced amateurs to
sign up for them: Norbert J. Schell from Beaver Falls, PA, Broadhead
and Paul from western New York state, and King, Cristman,
Luechinger, Franklin, Cameron, Thorne, and Rekouski all from the
Long Island Astronomical Society. In the December, 1944
Telecsopes, Ingalls reported thirteen advanced amateurs had ordered
8.2-inch lens blanks from Corning Glass Works, while in the same
issue Schell finished his discussion of the theory of correcting
aberrations in the Newtonian-Maksutov telescope.
Ingalls reported3 that in 1945 Arthur DeVany of Des Moines, Iowa,
had built a Maksutov for comet hunting, but it was never described
in Scientific American.
In July, 1946, C.J. Tenukest, R. Shaefer, and H. Pinnock of New
South Wales, Australia described in The Journal of the British
Astronomical Association how they built their 6-inch Maksutov from
data that Maksutov had provided in his 1944 paper in JOSA4.
Nearly two years passed since that first article in October, 1944
before the first report of a Maksutov made by an amateur appeared in
Scientific American for October, 1947. G. Camilli, of
Pittsfield, Massachusetts described building his 8-inch F/4
Newtonian-Maksutov following the specifications in the October, 1944
article by Schell. Then in the Amateur Astronomer page for
December, 1949, David Broadhead of Wellsville, New York, described
his Newtonian-Maksutov built according to the same specifications by
Schell.
John Gregory’s Maksutov telescope at the 1957 convention.
John Gregory’s Maksutov in 1957
The Maksutov field appeared to lie fallow for several years until
John F. Gregory became fascinated with the possibilities of this new
telescope. Not content to build just another
Newtonian-Maksutov, he had dreamed of a Cassegrain-Maksutov
configuration. In Maksutov's 1944 paper4 he claimed to have
computed, constructed, and tested successfully the Cassegrain system
but gave no numerical details. He also suggested the secondary
could be made by aluminizing the central spot on the inside surface
of the corrector lens thus simplifying the construction. Such
elimination of complexity appealed to John and he set about
designing a Cassegrain-Maksutov using the principles set down by
Maksutov. The success of his new design was firmly established
when he brought his 5-inch F/20 "Mak" to the 1956 Stellafane
convention and walked away with first prize for optical excellence.
John Gregory published an article in the March, 1957 issue of Sky
and Telescope describing his new design for a Maksutov-Cassegrain
telescope. He gave complete design specifications for 6-inch
F/15 and F/23 telescopes. "The assembled telescope will
perform so well that the amateur will be unable to find any fault,
and will wonder why he waited so long to construct such an ideal
instrument,"5 he wrote.
This was not John's first attempt at advanced optics. As a
student in mechanical engineering at the Case Institute of
Technology in Cleveland in 1949 he had designed and built a 5-inch
Schmidt camera. The main parts of the fork mounted camera
including the gearbox were aluminum for which he made the patterns
and cast and machined the aluminum. The mirror he made from a
6-inch plate glass blank and had a 14-inch focal length. For
the corrector plate he chose the design with the neutral zone at the
.707 zone and used the test method described by Harold A. Lower in
Amateur Telescope Making-Advanced, 1954 p.412, whereby a slit or
Ronchi grating is placed at the focus and projected backward through
the camera and the image is examined some distance in front of the
camera, about 10 feet, with straight lines as one moves from side to
side indicating a perfectly corrected system.
The same year that John Gregory brought his 5-inch "Mak" to the
Stellafane convention, other people expressed interest in the new
design and Allan Mackintosh stepped in and volunteered to form a
Maksutov Club. But that part of the story is best told by
Allan himself in the following letter.6
I have had a varied life. I was born in Inverness
(Scotland) in March 1909 but my parents moved to London when I
was about three months old as my father had bought a seat on the
London Stock Exchange. The First World War made an upset in my
family and my parents parted company in 1918 after I had been
enrolled as a chorister at St. Paul's Cathedral; my voice broke
in 1924 and I went to Dulwich College where I spent three years.
When I left school I got a job as a bank clerk with the Bank of
England but, after a year and a half I decided that the life was
not for me and resigned. This coincided with the market crash in
1929 and I had great difficulty in getting another job,
eventually I joined the Palestine Police in 1930, after I had
taken a BA degree at London University (evening classes).
I stayed in Palestine until 1938 when I got a commission in
the Colonial Police and was sent to the Bahamas. On arrival in
the Bahamas I found that the commission was temporary so I
applied for a transfer and got one to Jamaica. My job on leaving
Palestine was sergeant in charge of the political section of the
C.I.D. In Jerusalem, I had passed the government exam in Arabic
and also had been called to the bar in London after three years
of study in Palestine. I decided that anyone could do my job in
Jamaica and resigned; this was in the middle of the "phony war"
and on applying for a commission in the Army, I was told that
there were "no vacancies". I had to get a job quickly so I
applied to the U.S. Engineers Dept. who were then building the
base in Jamaica to guard the Panama Canal and was put in charge
of the native guards and watchmen for the base and made Justice
of the Peace for the base and advisor to the Colonel Commander
on native affairs.
I spent one of the best years of my life with the U.S.E.D.,
not least of which was that I met the American girl whom I later
married. When the U.S.E.D. handed over the base to the U.S. Air
Force, the commanding general in Puerto Rico decided that I was
too expensive and cut my salary in half; I appealed to the
Colonel who told me that I had been worth more than my salary to
him but he could not do anything about it, so I resigned and put
another application in for a British Army commission. The phony
war had ended by this time (1942) and I got the commission and
was sent to the Jamaica P.O.W. camp staff. After six months I
was sent to a "commando course"; I had a look round and saw that
most of the others on the course were about the early 20s and
that either I would make the running or be an also ran. At the
end of the course we were not told how we had finished but it
was customary for the first to be given the choice of three
stations to serve in, the second two stations and the rest where
they were told. The Brigadier gave me a choice of three, but I
asked him to send me over to Africa where the war was developing
as I spoke Arabic and was trained in intelligence - he said that
good officers were needed on this side also so I said that I
would like to go to where I would be the most use, He grinned at
me and said, "A soft answer turneth away wrath". At any rate I
spent the next year in the Leeward Islands, mostly in
Montserrat, a very pleasant island before the Soufriere volcano
blew its top, but with short stops in St. Kitts and Anguilla.
In 1944 I was transferred back to the Bahamas where the
quartermaster sergeant had embezzled mess funds. Somehow he had
heard that I was a barrister and chose me as officer's friend; a
court martial is a piece of cake for a trained lawyer and I got
him acquitted. Two weeks later I was sent for by the Brigadier
in Jamaica; he said, "You know he was guilty, don't you". I
replied, "A client is always not guilty for his lawyer and I did
my duty." He said, "Next time we will have you on our side, I am
going to have you made judge-advocate". So I spent the rest of
the war as substantive lieutenant, acting captain, local
(unwanted) major.
From the Bahamas I managed to get a couple of leaves to New
York where I married Helen, my American wife. When I was
demobilized in 1946 she came to join me in Jamaica; I had begun
a cabinet-making business - the only time I have ever made money
in my life as there was only one other good cabinet maker in
Jamaica and during the war he had become a prima donna - this
was the time when a number of hotels were being built on the
north shore of Jamaica so I cornered the market. Unfortunately
Helen had had rheumatic fever as a child and her heart was badly
damaged; in 1949 she became ill and I sent her back to New York
to her doctors who said that she could not return to Jamaica. I
sold out and joined her in New York, there were currency
regulations in force so I could only take out £1000 which lasted
a very short time what with doctors' bills.
I got myself a job as a warehouse supervisor with
Ballantine's Brewery pushing beer down a shute. This was in May
and I did not realize that it would come to an end with the hot
weather. They laid me off in October and said that they hoped to
see me next year. I got some short jobs over the Christmas
period and in March I joined the Sperry Gyroscope as a D-grade
parts inspector (the lowest form of animal life on the earth).
I did not mention that while I was in the Bahamas I picked up
a copy of Scientific American where Albert Ingalls ran a page
called, as I recall, Amateur Astronomer. I had always been
interested in astronomy and sent for a kit and built a 6"
reflector; it was a very bad one and I have kept the mirror to
show me that I was not always so good as I am supposed to be. It
took me six months to find out its shortcomings and when I did
so, I sent for a 10" kit which turned out to be much better. I
also joined Clyde Tombaugh's 16" club and took the blank all
round the Caribbean (fortunately the army paid for my baggage)
On arrival in New York I joined the telescope making section
of the A.A.A., then in the basement of the Hayden Planetarium,
where I got to work on the 16" blank - I also became one of the
class instructors. I also saw a copy of J.O.S.A. containing
Maksutov's article on his telescope - this interested me more
than a little.
In 1951 my wife died, she was a lovely person with a
delightful disposition and I was knocked for a loop. After two
years I had recovered a little and married Maria, my second
wife; she also had a fine disposition and we had 40 years
together - she died in 1993 of heart failure. I have been very
lucky with my wives.
In 1953 I was granted my naturalization papers and the same
year, after running the gauntlet of grades, I became a grade A
parts inspector at Sperry's, making some kind of record in speed
of promotion. We were then living in Glen Cove, L.I.
The Stellafane Conventions had been suspended during W.W. II
but in 1954 they were resurrected; so far as I remember about
400 people attended the early meetings - nothing like the crowds
who attend nowadays and maybe more pleasant because of it. In
1955 a hurricane descended on Connecticut and all roads going
north from Hartford were flooded, so I was unable to get
through.
1956 was a rather peculiar meeting in that the afternoon
session under the marquee consisted of a board of "experts"
(Aunt Sallies) who were to answer to the best of their ability
all questions on telescope making. For some reason I was invited
to be on the board and was detailed to answer questions on
Maksutov telescopes. I was a little surprised at the interest
shown and a hand count showed 35 people interested in making
one; I volunteered to do the dog work in forming a Maksutov
Club.
On returning to Long Island I sent round a circular letter to
the 35 and also to other TNs whom I thought might be interested
in buying corrector blanks in a bulk order and so saving a lot
of money. I eventually got 69 serious participants; 11 1/2"
diameter was decided on as this would accommodate the small
spread of the light path if a 12 1/2" mirror blank was used and
would provide a very powerful telescope. After contacting
several reliable glass manufacturers, I chose Haywards
Scientific Glass Corp. as giving the best price for the massive
blanks (1 3/8" thick of BSC-2 glass) and sent in an order for 75
blanks.
This was a very good choice as I have had no complaints at
all though all the blanks have been sold and a large number of
these large Maksutovs have been completed.
The Maksustov Club meets under the tent at Stellafane, August 16, 1958. Photo by Ed Lindberg.
The Maksustov Club meets under the tent at Stellafane, August 16, 1958.
With regard to the Maksutov Club, I decided that a lot of
information appeared to be required on how to go about building
them so I began the Maksutov Club Circulars and in order to save
costs bought myself a duplicator from Sears Roebuck; membership,
in the Club would consist of buying one of the blanks and
subscribing to the Circulars - no other membership fees. Cost of
the blanks was $75.50 and the Circulars were to be published six
times a year for a subscription of $5 at the beginning, so far
as I remember. This was a good deal and I ran the Circulars for
20 years until I retired and moved to England.
It soon appeared that all aspects of telescope making were
grist to the Maksutov Mill and I appealed for contributions from
all and sundry. Leading telescope makers, amateur and
professional, have been very kind to me and I have rarely been
pushed for material to put in the Circulars. In addition, Albert
Ingalls died some time after publication of ATM III and there
was room for another publication - telescope making is an
on-going pursuit and new ideas are continually surfacing which
would be a pity to deny to other TNs.
The early Circulars were almost entirely concerned with
Maksutov telescopes (as was to be expected) but as time went on
the subject matter broadened to include almost every aspect of
telescope making - such matters as curve generating, testing,
testers and a host of other matters. I came across many subjects
that had been invented previously but, in my opinion, had not
been sufficiently published and so were not readily available to
amateurs. These were published in the Circulars (with the
agreement of the original publishers) and include such matters
as the caustic test, the Gaviola test for convex surfaces,
interferometers, improved Foucault testers, spherometers etc.
etc. By the 70s the Circulars contained almost as much
information as the A.T.Ms (though more "state of the art") and
access to such a wealth of information was becoming clumsy so I
started playing with the idea of collecting the best of the
Circulars into book form and finding a publisher - but I am
getting ahead of myself.
In 1966 labour in Long Island was going through a bad period,
it was highly skilled but expensive and the major firms
(Grumman, Republic, Sperry and others) began to open up branches
in places such as Arizona. Sperry began laying off the Long
Island work force and eventually they reached my seniority (then
16 years) on a Wednesday. I took a sick day on Thursday and went
round to the Kollsman Instrument Co. and filled out an
application form. To my surprise the Personnel Manager came out
and asked me whether I ran an amateur magazine on telescope
making. I said yes and he said he had a job for me, that of
optical technician at 30c an hour more than I was getting at
Sperry's. I told him that I could begin the following Monday.
On Friday I went to Sperry's expecting to be processed but my
foreman told me that they had changed their minds and were not
going to lay me off. I said, "You can't do this to me, you told
me you were going to lay me off, I have got myself a better job,
lay me off!" I went to the personnel dept. where they tried to
give me a parting bonus, but my seniority was sufficient for a
pension and I insisted on this, rather to their disgust.
I went to Kollsmans and was posted to the "incoming"
department; I passed my probationary period without any bother
and it soon appeared that I knew more about optics than the
average technician. Shortly later I was sent to another
department for some reason I don't remember where I saw a 40"
beryllium mirror, which was being figured (this was a forerunner
to the Hubble telescope). It had been cast with a raised ring at
the back for mounting purposes - I remarked to the engineer in
charge that they would have trouble with this as there would be
a depressed zone on the mirror surface which would be difficult
to eliminate. He was impressed and said that I obviously knew
what I was talking about as they were having exactly that
trouble, would I be interested in transferring to his department
as an associate engineer. The answer was naturally, yes.
Maksutov telescope inspired by the commercial Questar telescope at the 1965 convention. Maker unknown. Photo by Walter Scott Houston.
Maksutov telescope inspired by the commercial Questar telescope at the 1965 convention.
I went back to "incoming" but my foreman said that he did not
want to stand in my way but that he had to have a replacement
for me. Optical technicians are at the top of the labor grades
and are far and few between so I waited - and waited. Meanwhile
I had answered an advert. by Indiana University for an
observatory engineer; I took a weekend and went out to
Bloomington Ind. to see and be seen - the professor who met me
turned out to be a subscriber to the Circulars and I asked for a
salary a little larger than I would have got as an associate
engineer at Kollsmans. After some haggling this was agreed, and
the job was mine - the University agreed to pay for the
transport of my now considerable workshop to be added to the
astronomical workshop but which would still belong to me.
I went out to Bloomington at the beginning of January, began
the job and got a house, my wife followed me a month later with
our bits and pieces, having hired a firm to pack the workshop. I
had the idea that an academic job would be very pleasant,
without the backbiting inherent in the commercial world - I was
wrong, my immediate boss thought I knew nothing as I did not
have PhD after my name so I never hit it off with him and found
that the backbiting went on just the same if not worse. I was
never very happy at Indiana University but I stuck it out for
ten years until I got a pension.
I attended Stellafane regularly every year and became one of
the regular judges for the competitions. My greatest boast is
that I was twice seIected as M.C. at the meetings. As time went
on more and more Maksutovs appeared in the competitions, more
often than not taking prizes.
In or about 1958 I received a letter from a Dr. Baar in Rome
N.Y. He asked me a number of questions about Maksutovs which I
answered to the best of my ability but I warned him that a
Maksutov was too difficult for a beginner and he would do well
to make a Newtonian or two before tackling one. He replied to me
that he had already made a Mak and would exhibit it at the next
Stellafane. So far as I remember, it ran off with the second
prize for mechanical excellence and the first prize for optics.
I have since been more circumspect with my remarks. Doc Baar has
since made six or more Maksutovs - more than anyone else I know
- most of them have run off with prizes at Stellafane. He is a
superb machinist and is now one of my best friends; we
correspond regularly and he has visited me in England several
times and I always stay with him when I visit the States (now
less often than I would wish - I have got old).
At Indiana University I was in charge of their three
observatories the Goethe-Link Observatory with a 36" interrupted
Cassegrain reflector, a 5" Zeiss apochromat and the backup
instruments - the Forest Observatory with a 16" reflector - and
the campus observatory with 12" Brashear refractor. These kept
me pretty busy most of the time, what with upkeep of the
telescopes and making accessory instruments as required. Life
would have been ideal if I had had a better boss.
I have only made one Maksutov but have not exhibited it as it
would not have been in keeping with my judging activities at
Stellafane. This has not interfered with designs and 12
different Mak designs have appeared in the Circulars, the work
of amateurs and professionals, to whom I am very grateful; in
addition there have appeared designs for tilted optics
telescopes, the Yolo and Solano reflectors (A.S. Leonard),
specrohelioscopes (sic) (F.N. Veio), interferometers and other
designs too numerous to mention. They all appear in the book
"Advanced Telescope Making Techniques." In fact the contents of
the Circulars became so wide ranging that it was difficult to
make them easily accessible by subject. In 1973 or thereabouts I
began to collect the best of the Circulars into book form. The
Circulars by this time amounted to about 1500 close typewritten
pages and prune how I may, it was impossible to get below 600
pages or so; this would have resulted in a very large and
unwieldy book so I decided to split it into two volumes which I
entitled "Optics" and "Mechanical". All this editing, in
addition to keeping the Circulars going, took a lot of time but
I had got it all into satisfactory form by 1975. Next came the
job of finding a publisher but eventually Perry Remaklus of
Willman-Bell Inc. agreed to publish it in paperback and a very
good job he has made of it (it is now available also in
hardback).
In 1977 I had served in I.U. for ten years - sufficient for a
pension - and retired as soon as the ten years was up as I had
never been very happy at the university. My wife wanted to
retire in England and although I had my doubts about this I
decided to keep her happy, so we sold our house, packed up and
moved over to Cornwall in England where I had found a house
during a visit (this was one of the worst decisions I have ever
made as the U.S.A. is an infinitely better place to live).
Running the Circulars from England would have been very
expensive and unsatisfactory so I arranged for them to be taken
over by a leading club - this was not successful (probably they
were not able to find a member who was willing to put the amount
of work into the project) and I don't think that any numbers
were published after I gave it up. The Maksutov Club collapsed,
this was unfortunate but placed as I was then, I could not do
anything about it - after all, people have to retire some time
and I was beginning to run out of steam, it was time for someone
younger to take over.
Maksutov telescope at the 1976 convention. Made by Rousseau of Quebec, Canada. Photo by Walter Scott Houston.
Maksutov telescope at the 1976 Stellafane convention.
The book is still on Willman-Bell's list and has sold a
considerable number due to their excellent handling of it. 1975
was early in the time of computers, they were expensive and
rather primitive excluding the main line computers which were
priced for universities and other large concerns. Private people
had to be content with calculators so I finished off the Optical
section of the book with a number of programs for programmable
calculators - these now seem to be rather elementary but could
be useful for those who are not computer gurus. The Mechanical
volume deals with all aspects of telescope making that did not
fit too well into the Optical volume. Many subjects deal with
the amateur's workshop and accessories for testing. One of the
objections in my mind to the A.T.Ms is that they have not been
edited to any particular plan and so reference to any particular
subject is frequently difficult; Ingalls once told me that this
was deliberate and necessitated knowledge of the books almost by
heart - this may be all very well, but wastes a lot of time if
the books are to be regarded as reference books. I have tried to
avoid this and have arranged the A.T.M.Ts to the best of my
ability in an order where the reference is to be expected - not
an easy task considering the variety of he information in the
contents. At any rate, the A.T.M.Ts are now the remnant of the
Maksutov Club which is rapidly becoming part of the history of
telescope making.
When I got to England in 1977, I found that there was little
interest in telescope making as such and I no longer had the
get-up-and-go to form a club, so I became inactive in telescope
making except that I joined John Gregory's club to make an 8"
2-element apochromat refractor. I have got so far as to
polishing the elements but unfortunately I had a couple of
operations for incipient cataracts and my eyesight is no longer
good enough for testing although I have one of Ralph Dakin's
sophisticated Foucault testers and a caustic tester. The
apochromat is now in the doldrums and although my eyesight is
improving, it a slow process and I don't know whether I shall
ever be able to finish it. Since I have a pretty good workshop,
I turned most of my attention to model making.
I still have a fairly large correspondence in telescope
making and know that it is still far more widespread than in
England although with the advent of Dobsonians there is perhaps
less activity in the more sophisticated telescopes. This is a
pity because the more advanced amateurs have potential of adding
considerably to the activites of the professionals. After all,
many of the professionals in the past began their careers as
amateurs.
Now that computers are within the budgets of most of us, the
boring part of telescope designing has largely been eliminated
and those of us who are computer gurus have a much easier time
of it than in the past. Amateurs may still take their place in
the forefront of telescope designing.
Schmidt telescopes are very difficult to manufacture owing
the (sic) the 4th order curve on the corrector. This is done
away with in Maksutovs as they can be made with only spherical
curves on the corrector (although a "touch up" on one of the
curves will improve performance) - the touch up can be done with
autocollimation so no special skill is required in making one
and there is no doubt that a catadioptric is better than an
ordinary reflector - it has a wider field and for a given size
has better resolution. Maybe Maksutovs will still appear in the
Stellafane competitions and, I hope, run away with some of the
prizes.
Dr. Ferdinand Baar, a medical doctor from Rome New York, had an
intense interest in photography. One day he saw a photograph
of the moon taken with a Questar telescope and thought that would be
an interesting thing to do. But after discovering the cost of the
Questar was over one thousand dollars he changed his mind and begun
to wonder if he could make such a telescope. Later he read
John Gregory's article in the March, 1957 Sky and Telescope
describing his new design for a Cassegrain-Maksutov telescope.
"I thought I understood it, so I went ahead and got some surface
material and surface glass from Edmund Scientific to practice with.
And it was very very nice and pleasant to glide one piece of glass
across the other. And within moments I was so entranced by
doing it that it slipped out of my hands and fell to the ground and
broke. That was my first lesson."7 He skipped his second
lesson. He would not enter the field of amateur telescope
making by the conventional route of first making one or two
parabolic mirrors for Newtonian telescopes as advocated by Allan
Mackintosh. He would start with the optics for a 4-inch
Maksutov, at the age of forty five.
As a matter of fact on the subject of John Gregory, two years
ago when we were on a cruise, John Gregory was there, he had
just remarried, his wife had passed away, and I realized at that
moment that this man had turned my life entirely around.
Before that I would do everything but nothing purposefully.
Nothing that gave me the satisfaction of grinding glass. I
grind by hand, I don’t grind by machine. I got so
entranced with that that now I’ve got a cellar that has a lathe,
first I started with a small lathe, now I’ve got a 12-inch
lathe, 12-inch swing, all the things that become necessary if
you are doing your own work. As I tell my wife, "don’t
ever worry about it, you know where I am, I’m down in the
cellar, you know who I’m with, I’m alone. If you hear me
talking I’m cussing myself out for doing something stupid."7
All told, Dr. Baar made four Maksutov-Cassegrains, starting with
the 4-inch. Then came an 8-inch F/15 which won second place
for optical performance at the 1967 Stellafane convention, and
finally two 11¼-inch F/15 designs, the first winning two first
awards at the 1969 Stellafane convention, one for optical and one
for mechanical excellence. Each one took about two years to
complete. Dr. Baar's words from a taped interview follow:
Now you can talk about the kids having a high on dope and
stuff, I have never experienced a high like taking double first,
the reason being is I wasn’t entering it to win an award I was
entering it for judgment. I mean this is what I think I’m
seeing, I think its good, as far as I know by my testing and my
numbers it’s good, but how good I don’t know. Like the Olympic
light bearer, I couldn’t get home fast enough to show my wife
what happened.
I donated this (the first 11-inch) to Hamilton College and
they asked why are you doing this? And I said because if I
don’t get it out of the house, get it out of the back yard I’ll
never build another one.
And the business of grinding, even a 12 inch disc or a 11½
inch lens to exact dimensions it’s almost a pleasure it’s not
work. When everything is right it’s as smooth as glass, it
just flows.
At one point I wasn’t certain whether or not I had a slight
hole in the center or a slight hill in the center. Most of
my work was done with Ronchi and I also use the Foucault for
counter testing as well, couldn’t make it out. It took
exactly six strokes, gentle strokes to wipe out. It must
have been a wavelength of glass or less. But to know where
to do it and how to do it that’s another thing. And this I
find very, very appealing, that two hands can do this.
I’ve been hooked by it for years. I find it entrancing,
more than I find using it. Now John Gregory, his kicks are
from designing. My kicks are from making. Somebody
else’s kicks are from using. To paraphrase the old Roman
phrase, all Gaul is divided into three parts, astronomy is
divided into three parts. Then the design, then the make,
and then the use. That’s it.
You want a blunder? Here’s a blunder. I had the
8-inch telescope with the irrigation tubing, aluminum irrigation
tubing, and not for window dressing but I thought of insulating
it, bringing it up here to Stellafane and just let it sit out in
the hot sun it’s going to get hot on the inside by the
insulation, I used gasket cork and put that inside. It’s a
very very good idea gone wrong because now the heat that is
absorbed by the mirror can not escape when things cool off and
you have a little will of the wisp floating in there all the
time. The cold air coming down against the glass of the
lens and then the lens transferring the cold down to the mirror
below which is much bigger in weight and density than the lens
so it’s going to be much slower to dissipate the heat than it is
to accumulate it. I found out about it by a very very simple
experiment. I had put three air holes in the back and I
blew into one of them like a puff of smoke. And it
disappeared. I got a small squirrel cage fan and put it on the back, and
you just keep blowing the air in. Once it cooled down so the
temperatures were equal, between the inside and outside it was
perfect.
Back me up a bit. How and when did you get connected
with the Mak club? After you got into your first?
After I finished the first one. You got my letter.
Then I approached Mac. about applying to the club, because it
was my idea that you had to build one or be building one in
order to apply. Now you can understand why his letter
reads as it does. (You don’t build a Mak for your first
telescope.) But nobody told me I shouldn’t admit it.
I didn’t. I started from what was there. I made
my own tools out of plaster, not out of plaster, but out of, oh,
it’s a very dense type of plaster, the name will come to me.
To make a Mak meniscus it’s a very steep curve. Did you
grind those out by hand?
Oh yes. I started with thick glass but there was a
curvature there. That curvature was thick enough and the
whole piece of glass was thick enough so you could have a whole
series of Maksutovs you could make in that size.
Did you find that out while you were making your first Mak did you say?
Second one. I wanted to learn more about what’s going
on and frankly I enjoy the Foucault, not the Foucault, (The
Ronchi?) the Ronchi test much better, much more reliable if you
do it right. Because the Foucault test can be warped by
body English mental body English. (You can fool yourself
into seeing what you want.) There’s so much flare and
glare. You’re not looking for ______, maybe it isn’t
there, well maybe that spot isn’t there and you kid yourself,
and how bright is that spot as compared to the hole on the
opposite side. Is that as bright as this is dark?
And it doesn’t tell you anything. But if you take the
Ronchi test and you set it up, you have to make your own jigs
with a floating micro head, horizontal and vertical, you can
make those lines move backwards and forwards into focus into the
focal plane and if you do it carefully enough you will see the
lines start to turn and go in the opposite direction that’s the
right turning and you go past the focal plane. So you can
innumerate your focal plane very very carefully and as it goes
back then the lines go through it. It’s like photographing
a picket fence as you come up to it and or come back from it.
Mac and I have fights on this. He doesn’t trust it because
when you use a Ronchi it’s hard to tell on the tips is it a
turned edge? The line comes up and you’ve got a little
lip, and the line seems to terminate into a little cup, and I
keep telling him it is simple, just reverse it. Because if
it is a turned edge the sign will be reversed in the opposite
direction, when you go past the focal plane.
Now you go in and out of focus and they should reverse themselves.
If they reverse themselves its a turned edge. If
they don’t reverse themselves and you still have this
semi-silhouette that might be interpreted as a turned edge then
it isn’t a turned edge. (Ya, I see what you mean.) And the
other thing is, anything over 5 lines 6 lines forget there’s no
accuracy. What you look for is, is there any wobble or any
wiggle as those lines come toward you, you know toward the focal
plane, and beyond and then start to dissipate into multiples
again on the other side and that’s the test. That’s what I
used to test my stuff, and when I take it out of the basement
where there’s no temperature differentials, a pretty uniform
temperature, there’s no problem.
That’s true. There’s another project waiting.
This is like a big garbage can in dimension.
Was this the 11 inch?
Yes, so the mirror is twelve. (Your first 11 inch?)
That was my first 11-inch. And I figured out all the
different ways to approach it. And you learn to do these
things, and as I say, by having the push pull screws fore and
aft I could make my slight adjustments so that I was collimated
perfectly, again that’s where the stars come in. If you
learn what to look for you can tell if your scope is out of
collimation.
What can you tell me about Mac? About how you got into the Mak club?
Well, I sent in my money and I started to receive notices. I
said, my God I had missed all of this information, I said how
much will it be to get all of the back issues? He sent me
all the back issues and I don’t think I got a real nights sleep
for almost a week, going through those things. That’s how
he did it, in other words, insight into the way other people
think.
I have mentored any number of people by letter. I have
done it by phone, never having met them, never having seen them.
The weirdest one is from a fellow from Prescott Arizona, he had
been bugging Mac he was trying to make a 13 incher, I don’t know
where he got the glass from, and he was getting into all sorts
of trouble. So Mac spooked him onto me, and I get this
long distance two hour phone call and I said the first thing we
have to do is decide on terminology, this is what these words
mean to me and try and get the concept across. And I said
the best thing I can think of is that you make a drawing of the
condition of your setup, he used a collimated setup, of what you
see. He was a good draftsman and I took one look at it, he
was using a grinding machine, he was using too much weight, he
was scouring the glass, he wasn’t polishing the glass, he was
scouring the glass. So I wrote and told him to try using
less weight. And he tried and it didn’t seem
to do much but I said take off more weight and little by little
by little the thing took shape. I had never met the man.
And now there’s a sad part of the story. He finished
it and about two or three months later his wife sent me a letter
saying he had died, he had pancreatic cancer which is fast, six
eight weeks and you’re gone. And she wanted to know what
to do with all the gear so I said she should get in touch with
the local club and see what arrangements she could work out. The
strange thing is I never met the man but he finished his Mak and
was happy.7
Diane Lucas at the 1974 convention. Diane and her husband built a 6-inch F/23 Gregory Maksutov telescope. Photo by Walter Scott Houston.
Diane Lucas at the 1974 convention. Diane and her husband built a 6-inch F/23 Gregory Maksutov telescope
Left-to-right: Ralph Dakin, Allan Mackintosh, and Dr. Ferdinand Baar, at the Hartness House during the 1979 convention. Photo by Jack Walch.
Left-to-right: Ralph Dakin, Allan Mackintosh, and Dr. Ferdinand Baar, at the Hartness House during the 1979 convention
Maksutov, D. D., "New Catadioptric Meniscus Systems," Journal of the Optical Society of America, Volume 34, Number 5, May, 1944, p.270-284.
Bouwers, Albert, "Achievements In Optics," Elsevier Publishing Company Inc., New York, 1950, Author's Preface.
Ingalls, Albert G., "Amateur Astronomer," Scientific American, December, 1949, p.60.
Ingalls, Albert G., "Amateur Astronomer," Scientific American, December, 1949, p.61.
Gregory, John F., "A Cassegrain-Maksutov Telescope Design for the Amateur," Sky and Telescope, March, 1957, p.236.
Mackintosh, Allan, Springfield, Marshgate, Camelford, Cornwall, England, letter to B. C. Willard, September 14, 1999.
Interview with Dr. Ferdinand Baar by Berton C. Willard, taped at Stellafane, August 13, 1999.
References:
Bouwers, Albert, "Achievements In Optics," Elsevier Publishing Company Inc., New York, 1950.
Fillmore, Warren I., "Construction Of A Maksutov Telescope," Sky Publishing Corporation, 1961.
Gerasimova, Ludmila A., "Dmitri Masutov's Scientific Legacy," Sky and Telescope, December, 1995, p.77.
Harrie Rutten and Martin van Venrooij, "Telescope Optics Evaluation and Design," Willmann-Bell, Inc., Richmond, Virginia, 1988.
Ingalls, Albert G., "Telescoptics," Scientific American, October, 1944, p.191.
Ingalls, Albert G., "Telescoptics," Scientific American, December, 1944, p.285
Ingalls, Albert G., "Telescoptics," Scientific American, October, 1947, p.188.
Ingalls, Albert G., "The Amateur Astronomer," Scientific American, November, 1949, p.60.
Ingalls, Albert G., "The Amateur Astronomer," Scientific American, December, 1949, p.60.
Maksutov, D. D., "New Catadioptric Meniscus Systems," Journal of the Optical Society of America, Volume 34, Number 5, May, 1944, p.270-284.
PPetrunin, Yuri and Trigubov, Eduard, “Dmitri Maksutov: The Man and His Telescopes,” Sky & Telescope, December, 2001, p.52.
Sky and Telescope Bulletin C, Sky Publishing Corporation, 1963, 1972.
13. Who's Who In The USSRr>1965-66, The Scarecrow Press, Inc., New York, 1966, pp.515-516.
