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Mosquitoes in summer and cold in winter.
Most amateur astronomers put up with these troubles in observing because
the construction of a warmed observatory room, such as those described by
Porter and others in "A.T.M.," is relatively formidable. One such
type is the turret telescope and of these there are now about half a dozen.
One of them warmed electrically, has just been constructed by Roelof Weertman,
of Dutch descent, member of The Amateur Astronomers Association of Pittsburgh,
residing at Division Lane, Observatory Hill, Vanport, Pa., 25 miles north-west
of Pittsburgh (mailing address, R.F.D. 1, Beaver, Pa.), and is shown in
figures 1, 2, 3 and 4. This is a larger, heavier more elaborate installation
than the illustrations at first suggest, the parts above the roof line alone
weighing 1500 pounds.
The telescope itself, when examined closely, proves to be more conventional
in type than the first glance suggests. It is a simple, ordinary Newtonian,
12 ½" in aperture, an f/9; its 100-pound counter weight being
carried on an extension of the rather than in a separate form. This makes
the tube 14’ long. There are no added reflections—no siderostat
as, for example, at Stellafane’s turret telescope. This of course,
entails reversing the dome—toward the building as shown.
In this type of telescope the observer within the dome looks into an eyepiece
which lies in the declination axis. He also stands within the polar axis,
which is expanded into a big ring to permit his entrance into it.
Starting at the bottom and working upward, as in the actual construction,
we have in this telescope the following catalog of elements:
- A reinforced concrete foundation on bed rock.
- A hollow tile building of dimensions shown in Figure 4—narrow enough (56") to permit the tube to reach the zenith on either side.
- A 2" plank floor and a 2" plank roof deck, the latter of tinned iron and painted.
Inside the building a stairway, as shown
(Figure 4). This is only 24" wide and is on the side nearer the reader.
At its head is a trap door 24" wide, and beyond this a fixed section
of platform also 24" wide. The entering observer pushes up the trap-door,
clibs up on the fixed platform, lets the trap-door down, and thus is on
a platform 33" wid and 48" long. There is ample room for two observers,
but three’s a crowd. Well, sometimes.
Surrounding the rectangular opening through the roof deck, where the dome
emerges, a large, rectangular, horizontal, iron base, 51" by 33".
Welded to this, four upright struts of 2"
pipe, to carry the tilted ring.
Fixedly welded to these four supports, a
315-pound ring of 50" inside diameter, made of 3 5/8" by 4 3/8"
angle iron, and slanted at 49° 15’. The web space between the basal
rectangle and the fixed ring is filled in with metal lath and plastered
inside and outside with 2" of concrete, through which there is a window
(Figure 2) 14" by 27".
Bolted to the fixed ring, three 3 1/8"
ball-bearing rollers from automobile rear axle housing.
Pressed on one of these three rollers a
10" worm wheel to provide friction drive to rotate the dome (done by
an automobile window crank).
At right angles to these rollers, two 4
3/8" thrust bearing rollers to prevent the movable ring and its attached
telescope from slipping off.
A 215-pound movable ring of 3 5/8"
by 4 1/8" angle iron. This carries the telescope, the dome, and the
hour circle.
Welded on the movable ring a 2’ length of 4" by 6" angle
iron, as a base, and on this a square piece of 12" flange beam, stood
on end. This unit carries the mounting for the tube, also a declination
slip plate, eyepiece holder, holder for 2 ½" elliptical flat,
declination and setting circle, declination worm, and ball bearings. A blueprint
of these details may be had gratis from the owner.
In its swing, or traverse, the eyepiece
does not rise more than 1’ above its lowest (E. and W.) positions.
On the above unit the tube, 14" inside
diameter, built of 1" by 1" tee-bar straights and 1 ¼"
by ¼" by ½" hoops.
At its upper end the tube carries a 100-pound
counterweight.
Attached to the movable ring a dome of galvanized,
riveted, sheet steel. Its interior is marked with latitude and meridian
circles. Prominent stars and nebulae are indicated on it, with their R.A.
and Dec., so that these and other landmarks can be found instantly.
A 12 ½" mirror which, before
silvering, was subjected to the criticism of Norbert J. Schell, Beaver Falls,
Pa., of off-axis and criss-cross off-axis telescope fame.
When the telescope is not in actual use,
the mirror is left in it covered by a latched lid. A 3’ sack like a
big mail-sack (Figure 3), is drawn over the end of the tube as protection
against rain and the tube is then turned mirror end up.
The 300-pound tube unit, incling the tubes
own 100-pound counter weight, is hung on one side of the movable ring. This
balanced by a 570-pound counter-weight mounted inside the dome opposite
the telescope.
In the photographs (Figure 1, 2 and 3) are
seen respectively: Weertman; Billy Weertman, Mrs. Weertman; John Cool, Billy
again, and a ground level, Mrs. Weertman again with Betty Tulip Weertman,
Billy’s goat (not, however,a billygoat). All—especially Mrs. Weertman—assisted
in the work, even Betty. That is, when anybody made a mistake, Betty was
thegoat.
Weertman says the observatory once served
as a fort. No sooner had he finished the concrete doorstop that a "halitosis
kitty" ambled up, drove him inside, and left his or her footprings
in the soft concrete.
Altogether, this is a notalbe telescope.