IDEAL hobby for elderly people is telescope making. Equally ideal for telescope making are elderly people, for these have long since discovered the necessary patience and tenacity. E. G. Richardson, 1238 Broadway, San Gabriel, California, is 79 years young and, in sending the photograph (Figure 1) of his 18", f/7 reflector, he says he has ridden the hobby for five or six years and made mirrors from 6" up, also a 5 1/4" refractor and seven 6" and two 12 1/2" flats.

Asked to give further detail about the 18" telescope, which is mounted as proposed by Porter in "A.T.M.", page 139, he writes: "Most telescope drives shown in the "A.T.M." books show the motor on the foundation or the frame of the telescope. I have tried that and attempted to smother the vibration, or rather cut it off from the telescope, by various kinds of pads and vibration insulators, but always found an annoying slight vibration, especially in some positions of the telescope, that interfered with sharp vision. So I have put my synchronous motor in a little two-story 'dog house' located on one side of the telescope platform just visible at the right in the photograph. The motor is mounted on a block of concrete which sits on a hole filled with sand. It is belted to a reduction gear which is on its own separate foundation, and the gear to a shaft which runs through a conduit under the platform and is geared to the worm which drives the large worm gear at end of the polar axle. I have absolutely no trouble from motor vibration.

"The upper story of this little house opens onto the telescope platform and in it I keep star maps and the odds and ends that one uses about a telescope. The switch-controlling motor is also here.

"An accessory that is rather important with so large a telescope is the observing step platform, which the photograph shows beside the telescope. At first I used an ordinary 12' stepladder, but it is surprising to note the number of persons who are more or less timid when they climb a few feet off the ground, especially the ladies. So I built the step platform. The steps are 10" wide and there is a strung rail on each side. You stand on the step that suits your height, lean on or grasp the rail, and take a look. You are relaxed and comfortable. Much of the time you are looking downward, the most comfortable position, and the step is so solid that the most timid feel no fear. For convenience in moving around, the two legs are provided with large casters. You grasp the lower ends of the rails and push it around like a wheelbarrow.

"Are there any advantages in a large telescope ? My experience is that when the seeing is good you get just that much more illumination and see better and more, but when the seeing is poor the big telescope gives no gain. Often, in fact, a smaller instrument will show more."

THE LATE J. H. Hindle, of England, was one of a minority of amateur telescope makers who prefer machines to hand work. Figure 2 is a clean-cut machine he was building when the war intervened. It never was completed. Hindle sent no descriptive data, but a close study of the photograph will afford useful ideas.

Hindle's machines for grinding and polishing embody a principle in which the mirror rides on top, just as in hand grinding, and is free to rotate of its own accord and does so rotate. Earliest origin of this idea, so far as is known, is the machine of Lord Rosse, described in Sir John Herschel's old volume, "The scope," dated 1861. Here it is the iron tool which rides on top (KL, Figure 3), mirror being beneath and immersed continually in water to within an inch of its surface. M is a round disk of wood connected with the polisher by strings hooked to it in six places, Sir John Herschel explains. "The bar DG," he adds, "opens into a ring which fits the polisher nicely, but without tightness, so that the polisher turns freely around." Thus Hindle's machine traces pretty clearly to the younger Herschel's.

Figure 4 also might have been the inspiration of the drill-press grinding machine described by Hindle in "A.T.M.", page 219, and is the old Lassell machine described by Sir John Herschel in the book named above. Amateur telescope makers as a class are too mechanical to need all the lettered details of this old drawing explained, except possibly that the gear O is fixed and the sector S is concentric with the axle P, though in bad perspective in the odd old drawing. It is hollow, and pinion T is adjustable anywhere along its groove: Hollow crank arm V is also adjustable. "By this mechanism," Herschel states, "it is evident that the pin [which drives the polisher J] will be carried circularly around a point which is itself maintained in circular motion."

Hindle's adaptation of this old principle was an improvement, in that he eliminated its rather Rube Goldbergish characteristics, and for them substituted more practical simplicity.

AS ALL amateur telescope makers know, you can saw glass with wet Carbo and the edge of a strip of sheet metal. The same procedure works with stone. In making the stone sundial shown in a temporary mock-up in Figure 5, your scribe sawed out its two 1" x 14" x 18" slabs of dense Devonian flagstone using No. 60 Carbo with the back of a one-man crosscut saw, each cut requiring about an hour. A drip-can was rigged up, a mound of Carbo was poured out near the cut, and this was fed in with the aid of a stick of wood as the right hand kept the saw moving. (In this instance, the owner of the saw, too distant to see clearly and ignorant of our familiar sawing technique, thought the stone was being sawed with the toothed side, and fainted.)

The uneven slabs were worked down with an old glass tool and coarse Carbo with ample elbow-grease, then fined with some of the familiar Carbo series.

The gnomon is a solid casting of bronze made and contributed by Fred. B. Ferson, Biloxi, Mississippi, author of the chapter on molding and casting in "A.T.M.A."

Diagonal lines for each 15-minute time interval from 7 to 11 A.M. were incised with the edge of a piece of sheet metal and Carbo. As they shallow up at the ends, this gives a curved illusion due to the shadows of their own edges.

The larger letters. were hogged out with an electrically driven "Handee Tool" and finished by hand with tools ground from old files and a knitting needle. The style of lettering was stolen from an inscription in England and it isn't orthodox (so, says an engineering friend).

The left-hand stone carries a graph of the equation of time for the summer months, also instructions for making the date corrections. By careful interpolation between the 15-minute lines of the dial, and addition or subtraction of date correction, it is always possible to set a watch and find it within two minutes (Sun's "time diameter") of correct time. Help from Mayall and Mayall, "Sundials," is gratefully acknowledged; also from Mayall and Mayall.

This is an east-facing, morning dial and it was built into the masonry over the door of a rock cabin (Figure 6) situated as per the legend carved on the dial: N. Lat 42°29'40"; W. Long. 76°54'46".

This cabin was begun 15 years ago and has provided a "piece of resistance" for annual two-week vacations. It was

placed 4' from the base of the 20' vertical cliff shown (note ladder) and in 18" of water. It therefore is an island. Some 56 cotton cement sacks were filled with mixed cement and aggregates and corded up on the solid rock bottom under water till they reached the surface. Into these, before the concrete set, was thumped the initial course of stone. The 12" wall then was continued to 17' above datum. Approximately 100 tons of 1 1/2" stone selected from the submerged talus by a submerged editor were brought in a rowboat and laid up in concrete mortar. No help was employed on this cabin-it was too much fun.

The flat, five ply, pitch-and-felt, Barrett Specification roof proved to be the largest and liveliest job of pitch lap making this writer ever did, particularly when the pitch, which was being raised toward 400° F, in an iron washtub over an open fire, flared up in a roar just as both feet became stuck in the hot, soft, just-mopped-on pitch tanglefoot. Has any reader ever found out why two things pick one time to happen?

The castellated design is a perversion of one contributed by Russell Porter. The front porch shown is a temporary eyesore to be replaced by a proper stone stylobate or basal surround, to give proportion. Porter calls this cabin "Karnac," other refer to it as a mausoleum.

Door hardware was forged from Swedish iron, to a tolerance of 10,000 wavelengths of the B line of sodium light.

Inside are a corner fireplace, Shipmate range, built-in table, a bunk 7' overhead and a stone floor to fall out on.

The "Fisherman Good Luck" invocation relates to the small-mouth black bass that lurk in the foreground in 20' of clear water and chuckle "they'll need it," as optimists troll past.

This is a vacation hideout, and there's more than one way to hide out on a two-week vacation far from the madding crowd and the razor (Figure 7), while laying stone masonry.

The preceding 53 lines and Figures 5, 6, and 7, give some indication of excessive mental strain under which Scribe Ingalls has been laboring the past 15 years. The purpose of this note is not only to disclaim all responsibility for the civil-life actions of our associate and especially for this month's department, but also to warn all "Telescope Nuts" of what may be expected from Scribe Ingalls 15 years from now, when he will have "retired" and be living in his own "mausoleum" (Figure 6.)-The Other Editors.

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