READERS OF THIS department will recall the description, published here in April, 1939, of a 10" off-axis reflecting telescope made by Norbert J. Schell, 1019 Third Ave., Beaver Falls, Pa., around an off-axis mirror made by T. G. Beede, Youngstown, Ohio-a mirror figured the same as if it were a section cut out of a larger mirror and to one side of the center. Figure 1, reproduced from that description, will recall and explain this telescope. In use, it gave refractor performance in a reflector because diffraction from the diagonal was eliminated, as was astigmatism, the shortcoming of the crude Herschelian.

The same team-Schell and Beede-have now gone one step further-the criss-cross off-axis telescope. Schell writes:

"Here is a sketch (Figure 2) of the horrible details, also photographs (Figures 3 and 4), of this telescope as it appears when put together in a rectangular plywood tube. The performance is pretty sweet-better than the simple off-axis. You ask me to tabulate the specific advantages. Here they are:

1: Long-focus primary easier to figure than short focus.

2: Folded-back focus, a-la-Cassegrain-most convenient observing position.

3: Flat only half the size of the primary -easier to make than full size.

4: Tube length only half as long as focus.

5: Disposition of surfaces permits light baffles, eliminating any light not reflected from primary.

6: Wooden tube-better than metal. Also, because of the shape of this tube, most of the light is kept away from sides of the tube, reducing tube air-current troubles.

"This combination of mirrors can be arranged for use of a warmed observing room, by shooting the light from the flat up the polar axis-no added reflections being necessary.

"This arrangement of a long-focus mirror and half-size flat was thought up by Beede. The only part I contributed was to twist the main mirror around 180 degrees and thus bring about the criss-cross feature.

"No particular trouble was encountered in getting a good alinement.

"The mounting shown was made in a hurry, to try out this design. It is stiff enough, but no considerations of appearance went into it.

"The 10" mirror works as a section of an imaginary paraboloid of 46" diameter. This is necessary in order to get far enough off axis to introduce the 6" flat at the position wanted without obstructing the light reaching the primary.

"The primary mirror has a 148-1/2" focal length and is offset 19" from the theoretical axis. The 6" flat is 67" from the primary and the focus is 81-1/2" from the flat."

MORE of Beede's mirror work: "Enclosed," writes Leo J. Scanlon, of Valley View Observatory, 186

Van Buren Street, Pittsburgh, Pa., "are pictures (Figures 5 and 6) of a 6" Cassegrain telescope -the world's best-made for me as a token of appreciation by two other amateurs. The 6" mirror and secondary were made by T. G. Beede of Youngstown; the mounting, tube, and tripod by Emmor Kelley, of Brownsville, Pa., (he of anniversary whistle clock fame-see this department, Oct. 1938). Beede did a perfect job on the mirrors, and Kelley has produced the finest telescope of his career.

"The tripod has tension-taker-uppers at the headjoint to make it secure. The legs are braced by a special device attached under the tripod head.

"The tube is of Micarta, cloth base, finished in several coats of black Duco rubbed to a satin surface. It is removable from the mounting, this being done by unscrewing the two trunnion bolts. Incidentally, these can't fall out when unscrewed. The cell has a ventilating plate (Figure 5) which can be opened or closed at the turn of a knob near the eyepiece.

"The yoke was fabricated by welding 2" tee-section steel girders and is exceptionally rigid. The slow motions in RA and declination are velvet smooth and have no blacklash, as there are provisions for eliminating this or for applying tension to the bearings in both coordinates. The tripod head and polar axis housing are of cast aluminum.

"The only contribution I made to the telescope," Scanlon continues, "is the method of adjusting the secondary mirror. I gave Kelley the idea and let him work it out-so all the credit for its success belongs to him. The secondary mirror is held by the usual fins to a ring. This ring can be tilted in any direction, or made to approach or recede from the main mirror, by using a screwdriver on three adjusting lugs at the eyepiece end of the telescope, through the holes shown by the arrows (Figure 5). Turning these lugs operates a left-right bushing at the ends of the rods supporting the framework for the secondary. This framework (Figure 6) slides down into the tube and is guided and spaced by additional lugs bolted to the inside of the tube itself. The secondary adjustment is then quite simple; just remove the eyepiece and look in while you adjust with a screwdriver from the rear of the cell. Any slight error of adjustment is immediately corrected. You can line it up perfectly while looking at a star. I think it's great!

"Figure 6 also shows the light-shield for cutting off direct illumination from the field to the eyepiece, during daytime use-though it is left in permanently."

Concerning tubes such as the one used on this telescope, Scanlon writes: "There are two kinds of tubes available at the Westinghouse Company in West Pittsburgh, Pa. One is a laminated Micarta paper tube rolled under pressure on mandrels and glued with a Bakelite varnish. The other also Micarta, is a cloth material wound on a mandrel in similar fashion, same varnish binder of Bakelite cement. Each is baked to harden and is quite as strong as aluminum, without the metallic drawbacks."

For several years your scribe has been hearing echos of Beede, of Youngstown, Ohio, mentioned above in connection with two telescope descriptions, generally from the direction of western Pennsylvania. Leo J. Scanlon some time ago told your scribe that he was an old time worker of most remarkable skill. N. J. Schell, mentioned above, also discovered him and so did others. Yet, never a written word or a syllable came from the man himself, until one began almost to believe him legendary, like Homer. Thanks to Schell, who has now provided some requested personality notes, and to Beede's sidekick, Leo F. Grandmontagne, Box 833, Youngstown, Ohio, who finally managed to get him to submit peaceably to being photographed (Figures 7 and 8), Beede comes at last into focus.

He is about 68 years old, a retired master plumber and plumbing contractor, and started making mirrors in 1898, after visiting an elderly clergyman named Dr. John Peate, of Greenville, Pa., who, after 16 years of mirror making, had cast a 62" mirror, said now to be at the Smithsonian Institution. He has been making mirrors ever since, mostly as an amateur. He was once visited by Prof. Ritchey. "Beede does not hurry his work," Schell states, "but when he turns a job loose you can swear by it. On jobs, such as flats, his methods are tried and sure, and he carries them through without any back-tracking, and in surprisingly short time considering the quality of the finished product. He does all his work by hand.

"He has his own methods of preparing Carbo and rouge," Schell continues, adding, "I have seen some of his Carbo that he has floated three hours. He does not use emery for finishing, saying it is too slow, and that the fine Carbo produces a better surface anyway. He floats his rouge and classifies it as fast-cutting, slow, and so on. He makes laps with a pen knife that look like the idealized drawings in the book, then coats them with mixtures of about three kinds of wax. He uses coal-tar pitch."

Beede is said to have a keen sense of humor despite the relaxed expressions of the photographs. "He is an indefatiguable worker, with unlimited patience," Schell states, "and can produce a beautiful. smooth optical surface of any kind whatever, with perfect edges and correct within limits too close to measure with the knife-edge test, and do it right along. He is considered by a host of amateurs who know him as the dean of amateur telescope makers The Mahoning Valley Academy of Science is preparing to honor him for his development of a method for figuring off-axis mirrors.

"Why hasn't Beede ever told the world about himself?" Schell was asked. "He is by no means gabby." was the reply an understatement.

CREDIT is due to William R. Harlow, an amateur telescope maker and freshman at Miami University, Oxford, Ohio. for an invention consisting essentially of the application of a stroboscope to a telescope for improving definition when observing. Prof. A. E. Douglass, director of the Steward Observatory at the University of Arizona, who has had many years of actual experience at the eyepiece in observing Mars both there and at Lowell Observatory states that he believes the idea fruitful, and it is hoped that other amateurs better situated for trying it out than Harlow will now do so.

Harlow states that he has made a 6" reflector, a 10" Cassegrainian, a 6" simple refractor, and then an 8" achromatic refractor, working on the last-named from J. R. Haviland's instructions in "ATMA." Then he tackled his stroboscopic application. "A careful examination of the shimmering of an image," he states, "will show that about 75 percent of it is harmonic, the remaining 25 percent erratic, due to the varying air currents." These things are described by Prof. Douglass in his chapter on "Atmosphere, Telescope and Observer," in "ATMA." "If some form of stroboscopic disk is interposed somewhere along the light beam," Harlow continues, "with a rheostat control on the disk motor, a lot of shimmering will be stopped.

"The slot in the disk should be a trifle wider than the light beam at the point along the tube where it is applied. With one slot (Figure 9) a speed of half the motion of the image will stop it; with two slots (upper right) quarter the speed; and so on. I found it worked best at the declination axis, where the vibration was least. The motor should be cushioned in some way."

Perhaps one's first thought on noting this description is: "But won't the illumination of the image be greatly reduced?" No, it would not, as Harlow explains, "because of the persistence of vision-though this would be detrimental in photography, where there is no such phenomenon."

J. R. Haviland, to whom this communication was shown, thought "it really is something, if it works." Professor Douglass, commented as follows: "I am a lot interested in Harlow's stroboscopic device. I am satisfied that a substantial amount of the flicker in the image is harmonic. I think this applies to a star or small object like a satellite of Jupiter. [One of Professor Douglass' specialties is the observation of Jupiter's satellites. Another is tree ring research; he is the scientist who has dated many old Indian structures in the southwest by means of the rings in the timbers found in their ruins.-Ed.] I suspect that, in the case of a disk the size of Mars", Professor Douglass continues, "the situation is most complicated. Atmospheric currents are not so easy to study on a planetary disk as on a star.

"Harlow's stroboscopic device will work when the telescope lens is small compared with the wave of the currents in the air, for then you have good definition (but low power, limited by diffraction effects) and a swaying image. This stroboscopic device would decrease or stop the swaying of the image and is a very neat idea; but in a larger aperture which covers several or many waves at once this device, as described, would not aid because the image does not sway but is badly confused due to the varying refraction of the many slopes of the air waves, all in the objective at once.

"So the device should work for a small telescope, 2 or 3, and sometimes 4 or 5, inches, depending on large size of air waves and freedom from cross-currents or local currents (which I used to call ripples), but with increasing aperture (5 to 10 inches) the results might or might not be good (1 am thinking of condition in a good climate such as here in Arizona). For bigger instruments, up to the giant reflectors, it would do no good at all. However, the idea is fruitful. Is there any way some harmonic correcting device could be made to work in a big aperture? For example: On an observation night make a sketch or a photo of the waves as seen with out the eyepiece and in full aperture; transfer this to some dichromated gelatin photographic film on good glass, that displays variable thickness of film without blackening; insert this in the beam and have it vibrate transversely to the waves on a motion found to match the shifting of the waves themselves. This would be very difficult. It might better be tried the following way: Make a film (or choose one of a lot on band), place it in the beam (by motion along the beam it might adapt itself to the proper size-refractive power of wave slopes would be more difficult to match), and then add the stroboscopic slit of Harlow's, adapting the rate to match the wave changes.

"Thus, in short, if a transparent pattern could be made to effect wave correction in some one position of the waves with reference to the telescope lens, then the application of Harlow's stroboscopic device could, I think, be made to pick out the majority of the instants of time when that correction would be an advantage either in photography or visual work."

Commenting on this, Harlow states that he has no facilities to carry the idea further, hence the idea is presented here for other amateurs or professionals to carry on. Harlow adds that he had himself discovered what Prof. Douglass pointed out-that the effect diminished as the aperture increased, and that he had had better results with his 3 refractor than with his 3" reflector and 10" Cassegrainian, but had not known whether or not this would always be true.

WHETHER reflectors with open tubes are superior to those with closed tubes is the subject of a perennial debate. Most recent slant on this is found in the January number of The Journal of the British Astronomical Association, where Dr. W. H. Steavenson's opinion is pointed out. For a telescope which is to be used in the open the disadvantages of the closed tube would be outweighed by the advantages. Most lattice tubes are used under domes, but if used in the open, dewing of the mirror may occur. Two other members pointed out that they find that aluminized flats do not dew in the way that silver flats would under the same conditions.

The same number of The Journal contains a six page article by M. A. Ellison, son of the late Rev. W. F. A. Ellison, describing a Hale spectrohelioscope which he has just completed. This is the second in Great Britain, (by an amateur), A. M. Newbegin having made the first, two or three years ago. M. A. Ellison says the work required two and one half years, and that the performance has come up to expectations.

THE TELESCOPE, popular astronomical journal, March-April number, has a noteworthy, 10-page article on the 200" reflector, by Anderson and Porter. Two thin dimes, Harvard College Observatory Cambridge, Mass.

STELLAFANE Convention, Sat., Aug. 10. 

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