FIGURE 2 shows the observatory and Figure 3 the telescope owned by Mrs. Marion Grant Bowen, of Carson City, Nevada, who was helped in the construction by a brother. The ground floor of the 16' by 22' observatory literally has the comforts of home a foyer, dressing room, bathroom, and library. Many a mere man dreams of such a retreat, well out of shouting distance from domestic appeals for help and, as Ellison put the expression, "with a lock on the door and the key in his pocket." Access to the 11' dome is by way of a hatch that opens outdoors, thus shunting warmed air away from the instrument. The telescope (Figure 3) is an f/6.9, 10" reflector with unusually clean tube, built of cast aluminum rings held on Shelby tubing by opposing nuts. Internal diameter, 12". Setting circles read to 5' in R.A. and 1 degree in declination. There is a slip ring. Cell carries a 9-point floatation system. Altitude at Carson City is 4650 feet, with probably enviable seeing conditions. These data were furnished by Robert Blackmore, 132 N. Arlington Ave., East Orange, N. J.

AMATEURS who sometimes complain of disadvantageous working conditions may take renewed courage after studying Figure 4. which shows the sky-hole in the level roof of a typical Brooklyn residence, with the hatch cover off. William S. von Arx, 573 Monroe St., Brooklyn, N. Y., the author of the chapter on "Stellar Photography," in ATMA, nightly sits on a temporary cross-board at ceiling level 18" below this roof and operates the equipment shown, getting excellent results despite the strong sky-glare of the great city. He describes this equipment as follows:

"THE photographic equatorial shown carries a 508-mm (20") focus, f/6 Eastman Aerial objective, 3.3" aperture which just covers a quarter plate nicely. The area of sky included per plate is about 11 degrees by 14 degrees, of which 10 degrees square yields excellent definition-scale: 1 mm=400 seconds. The guide telescope mounted on the camera is a 72-mm triplet of 21.5 focus, provided with the usual reticle and a 1/4" eyepiece. The 'carbureter' attached to the lower end of the camera is a small clock which beats four times per second, permitting the observer to count seconds with more precision than 'one- chimpanzee-two-chimpanzee-three-chim . . .' and also relieves him of the necessity of removing his attention from the guide star in order to know how far the exposure has progressed. Near the clock is a thumbscrew for moving the plate holder in R. A.-multiple exposure plates. The rubber bulb and hose operates the 4" Packard-Ideal shutter (square panel over the lens), which works with a reassuring clatter but without noticeable vibration. Exposures as short as 1/5 sec. can be successfully managed by biting the bulb. This method is often pursued in times of bad seeing. Operating the shutter with the teeth leaves both hands free for guiding; the latter being a busy business at times. More than this, a mental count is kept of the seconds during which the shutter is open.

"Since the mounting is unhoused it was necessary to make it easily demountable. To accomplish this the yoke simply pulls out of the north and south bearings, thus reducing the mounting to three easily handled units. One by one-according to a very rigid sequence-the parts are stowed below the roof level and the hatch cover drawn to. Three sockets were cemented to the roof when the polar axis was considered well set, so that the polar adjustment is identical each time. It has proved to be sufficiently accurate to continue exposures over two or three nights-taking the whole mounting down between times-without perceptible damage to the images even under microscopic examination.

"With the exception of moving parts, the camera and mounting are made entirely of wood finished with lead gray paint, so that it may be more easily seen at night. The camera is made of 1" by 7" clear white pine, the yoke and north pier of 2" by 3" Douglas fir, and the south pier of 2" by 6" clear white pine, all well seasoned, quite rigid and conveniently light in weight. Where necessary the wooden members are reinforced with heavy corner irons and lag screws.

"The clock drive built into the south pier is of somewhat unconventional design. Suitable worms being quite expensive, it was decided to use a friction drive instead. A smooth, accurate motion in R. A. is secured by a small round-belt pulley bearing directly on a large (12") "V"-belt pulley having a length of 5/8" o.d. high-pressure cord rubber tubing cemented in the groove. The small is pulley is driven by a train of worms and gears originating in an electric phonograph motor. The ratio is such that the motor runs at about 40 percent top speed and 80 percent standard speed. For adjusting the rate of the clock a hand screw (on the right of the S. pier) which has a fine metric thread bears down on the speed control of the governor. On the left, next to the main switch, is a hand control which accelerates the motor any amount over the sidereal rate and holds it there for widening objective prism spectra known amounts. On the north side of the pier is a third control within easy reach from the eyepiece, for momentary acceleration as needed in guiding. A switch on a length of cable 'cuts the gun' as necessary. With the second control down and this switch in hand, a star image can be made to commute between two lines in the reticle at a uniform rate as many times as is necessary to build up an image of a star's spectrum. With the switch 'on,' the image advances. When it reaches the end of its prescribed course the switch is thrown 'off' and the diurnal motion of the earth carries it back to its starting point. The objective prism spectrograph (f/4.5, 10.5-cm. focus with a 60 degree crown prism) clamps on the east trunnion of the Dec. axis at an angle of median deviation, which permits the guide telescope to be used on the star under observation.

"The camera is also equipped with a 15 degree crown objective prism, a 'normal' grating (0.99m) and a 90 degree prism for photographing the North Polar Sequence since it is in the blind spot of the mounting. This blind spot is a very definite disadvantage but, pound for pound, few mounting designs equal the stability of the double yoke. Then too, as those who work with the Hooker telescope solemnly affirm, 'There is nothing interesting north of plus 67 anyway!"

LEST new readers of the magazine now run away with the idea that, in order to be an amateur telescope maker one must be able to concoct creations like those just described, Figure 5 is inserted in order to show a more typical maiden effort such as those who successfully finish instruments of a more ambitious kind have themselves begun on. This is a 6" reflector made by John J. Mosher, 26 Lansdale St., Rochester, N. Y., and the parts of the mounting are made up of pipe fittings-a reducing T, a short nipple, a 45 degree elbow, another short nip, and other standard fittings for the upright. As such fittings often have some looseness and shake, set screws in tapped holes take this up. No blueprints for specific telescopes such as this are available, each instrument being the original design of the maker, based on general principles explained in "Amateur Telescope Making." Generally the beginner thinks his first telescope will be his only creation but the bug gets into his blood stream and he discovers he wants a new and more ambitious one about as often as his wife wants a new hat. Well, it will costs him something less than he would otherwise spend in the same time burning up gas on the road, overeating in restaurants, or making whoopee with some well-upholstered platinum or excelsior blonde in night clubs.

WHILE a 6" diameter is the optimum size for the beginner, a very few make 4" or 5" sizes and Figure 6 shows a 4" "Baby Grand" made several years ago by J. P. Hansen, Framingham, Mass. who says it "works great," and cost "around $25." The stand is from an old drawing board, the patterns were homemade and the castings were made in a local foundry, while others were cast in aluminum in the home basement, using metal melted in the furnace, the molds being of plaster of Paris. Hansen wisely mentions that such molds must he thoroughly dried. He says he was over anxious to get the mounting finished, poured the metal into wet molds and "the whole business blew up to the ceiling." This is an unusually trim little telescope with excellent, rugged design and attractive appearance and, though it is small, it has a much better mounting than the average beginner's No. 1 job usually is or even needs to be.

ANOTHER simple telescope-a maiden effort-is shown in Figure 7, this time an 8" but with simpler mounting than the previous one. H. C. Wilson 877 Chester Road, Charleston, W. Va., is the maker. Tube, galvanized iron with heavy wire rolled into the top for stiffening. Mounting, 4" pipe fitting plus an old tree stump-very solid. Cost, $27.50.

SQUARE tubes for telescopes function as well as round ones and are much easier to make. Figure 8 shows how Paul Mowbray Wheeler, Professor of English at Winthrop College, Rock Hill, S. C., converted a cypress box into a tube, adding scantlings in the form of a rectangle within which this tube, with its 7" mirror, was pivoted. There are bearings at top and bottom ends of the rectangle ("double yoke" is the technical term for this) and the whole is a thoroughly efficient and rigid kind of mounting, simple to make, easy to take to pieces or erect, inexpensive. The world's largest telescope, the 100" reflector at the Mt. Wilson Observatory, is mounted similarly. The large steering wheels on the two axes are the maker's idea, being used for turning the tube in declination, the astronomer's equivalent of latitude, and in right ascension, the equivalent of longitude.

ANOTHER double yoke mounting appears in Figure 9, the photograph having been sent in by R. P. Hassler, of R.F.D. 1, Leverne, Minn. The tube is of metal and the yoke and frame are made of steel channels and an old motor car chassis. This is a 10" telescope-rather beyond beginner size.

"IF paint is applied to galvanized iron or zinc, it will peel off after a time, but the following treatment will make it stay on," according to Lawrence A. Cox, 47 Upper Green East, Mitcham, Surrey, England. "Add 1/2 oz. dilute sulfuric acid to one pint of saturated solution of copper sulfate. If this solution is swabbed on to the metal liberally, it will immediately blacken the surface. It should not be wiped off but allowed to dry on, and the surface then given a coat of gold size. Afterward it can be dead-blacked or painted otherwise as necessary."

WHEN well-meaning friends insist on labeling you, even in public print, an "astronomer,' often to your embarrassment, or where they do not realize what a real astronomer is and what an amateur astronomer isn't, the following quotation taken from an account of the life of the late Ambrose Swasey, the famous professional telescope builder, by Prof. J. J. Nassau and published in the Journal of Applied Physics (New York) might be read to them: "When once Mr. W. H. Crocker of San Francisco remarked, 'Why, Mr. Swasey, you are an astronomer,' he replied, 'When I was a boy, my father kept a great number of sheep and when working around the barn and with the sheep, some of the wool rubbed off on me, but that didn't make a sheep of me."'

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