Last year so many attended this informal confab of amateur telescope makers and astronomers that it was a question whether to rent a circus tent next time. People came from all over the east, and some from greater distances, to commune with other enthusiastic telescope fans. There is a small hotel in Springfield, also very limited "quarters" (for men) at "Stellafane." A good many come in their cars, bringing the families and tents. There is all sorts of room to camp, and a good spring of water is nearby. Leave your dress suits in mothballs, as this is not a "high hat" affair but just a friendly, comfortable gathering of "folks." If you have made a telescope or invented any kind of optical dingbat of which you are unashamed, bring it along and give the other fans a chance to knock it. If you wish to make any special arrangements write to the Secretary of the "Telescope Makers of Springfield," Oscar S. Marshall, 135 Wall Street, Springfield, Vermont.

WHEN the hot months come people usually let up their efforts in telescope making; they had rather be out of doors than working in the cellar workshop. About September the orders for the instruction book "Amateur Telescope Making" always begin to come in thick and fast, and then we know the game is on again. However, to judge from the postcard announcement which is reproduced on this page, telescope making activities never wane, even in hot weather, in lively Los Angeles. Fragments of information reach us from time to time about the various activities of the Amateur Telescope Maker's Society of Los Angeles, the latest being that they have gone in heavily for refractor making. The seed that was dropped in that city -four years ago is growing-in fact, already has grown-into a thriving tree. We wish the amateurs of "L. A." would send in accounts of their doings, with photographs of the jobs done, for publication. .

Some of the telescopes made by amateurs have been pretty elaborate affairs and some are not so elaborate; However, we publish them all because we do not wish merely to feature the finer ones. A worker who builds a small instrument may lack facilities for making a large one, he may not happen to have had special training in machine work, he may not be rolling in wealth, but he derives as much fun from making it as the fellow who puts together a big one. One thing, however, is that we have found that the work is not suited to boys. Very few have made good at it, ant those, we suspect, were unusually bright lads with an aptitude for mechanical work and for thinking.

JUST how inexpensively a telescope be made never has been settled, but Bob Burns, of 326 Courtland N. E. Atlanta, Georgia, has shaved a big chunk off the average cost of a six-inch reflector. The materials for a six-inch telescope which will magnify from 50 to 200 diameters usually cost about 25 dollars. The initial outlay is ten dollars for a prepared package: containing the glass disks, abrasives, an pitch. With these the mirror is made and then after some time the eyepiece an diagonal prism, each at six dollars, are obtained. The average amateur worker can be trusted to pick up the remaining parts, chiefly secondhand, for little no more than the remaining three dollars. Often we are asked whether there is a way to ma a telescope still more cheaply than this. There is. If one can pick up microscope eyepiece t will save six dollars. Other savings are possible some cases, depending o the worker's resourcefulness.

A four-inch, instead of six-inch mirror, provided the main solution of a cost problem, in the ease of Mr. Burns, who made a telescope at a total cost of $5.36. We asked Mr. Burns to tell the amateurs how he did it. Here is what he reports.

The four-inch glass disks were cut from two pieces of one quarter inch broken windshield glass which I procured for the asking at an auto junk dealer. Cost . . . . . . . . . . . . . . . $ .00

Cutting and grinding the edges of these disks, at an automobile glass service station, was . . . . . . . . . . . . . . . . .25

The American Optical Company furnished me three grades of emery (No. 60, 120, 302) and the rouge for . . . . . . . . . . . . . . . . . . . . . . . . . .65

Silver nitrate, one quarter ounce, cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

I used household ammonia and formaldehyde to reduce the silver nitrate when silvering the mirror. Cost to me . . . . . . . . . . . . . . . . . . . . . . . . .00

A wood turning shop made the wooden mirror cell for . . . . . . . . . . . . . . . . . . .50

The 24-inch tube is made of polished sheet zinc, and cost . . . . . . . . . . . . . . . . . .90

For my diagonal I used a piece of one quarter inch plate glass of oblong shape, 1 1/4 by 3/4 inches, corners rounded, the supports being soldered to the inside of the tube. The cost of this was . . . . . . . . 00

The eyepiece was taken from a "pencil" microscope which cost . . . . . . . . . . 1.00

Brass tubes for eyepiece (plumber's shop) . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Lumber for tripod, cut to size . . . . . . . 1.25

Bolts for tripod . . . . . . . . . . . . . . . . . . . .20

Lacquer and brush for painting tripod and inside of tube . . . . . . . . . . . . . . .20

The total expenditure came to . . . . . . . . $5.35

I polished my mirror by gluing the crown of an old felt hat to my tool and polishing on this pad. It finished out in about 1 1/2 hours. I made no attempt to change the curve from a sphere to a parabola.

With the three quarter inch, double-convex eye lens the telescope gives about 50 to 60 diameters magnification. The innumerable craters on the moon are very interesting.

PHIL E. CHURCH, 104 East LaRue, Streator, Illinois, sends in a few pictures of an unusual telescope. He says: "Three of us did the work, but 'Friday' Angier conceived and built the mounting. The steering wheel is for rapid control in directing the telescope but there are slow-motion screws and these are turned by means of sewing machine flywheels. The three of us, 'Friday,' Herbert Prafcke, and I, are greatly satisfied with this arrangement and we invite comment from other amateurs', Are there any who want to break a lance with these three musketeers?

HERE is an interesting hint. Harold A. Lower, 1032 Pennsylvania Avenue, San Diego, California, who is always trying out something new in amateur optics, writes: "I discovered a new use for a microscope the other day. The mechanical stage makes an excellent arrangement for controlling the knife-edge when making the Foucault test. Just attach the razor blade to the mechanical stage by means of a small D-clamp, and it works as if made to order.

The Society for Amateur Scientists (SAS) is a nonprofit research and educational organization dedicated to helping people enrich their lives by following their passion to take part in scientific adventures of all kinds.