200-INCH HALE TELESCOPE—HUBBLE 185 
Actually the dimming factor (the reduction of apparent brightness) 
is a simple fraction represented by velocity of recession divided by 
the velocity of light. Recession at one one-hundredth the velocity 
of light reduces the apparent brightness by 1 percent; at one-tenth 
the velocity of light, by 10 percent, and so on. Thus the effects of 
recession would be negligible until velocities of several hundred miles 
per second were reached. The effects would be appreciable at a 
few thousand miles per second, and conspicuous at several tens of 
thousands of miles per second. 
If red-shifts are evidence of actual recession, the dimming factors 
should become appreciable near the limits of measurement with the 
100-inch and should be conspicuous near the limit of the 200-inch. 
At the very limits of direct photographs with the 200-inch, the factor 
should approach the order of 40 to 50 percent, and should be unmis- 
takable. 
We may predict with confidence that the 200-inch will tell us 
whether the red-shifts must be accepted as evidence of a rapidly 
expanding universe, or attributed to some new principle of nature. 
Whatever the answer may be, the result will be welcomed as another 
major contribution to the exploration of the universe. 
I have mentioned the three specific problems of canals on Mars, 
relative abundance of chemical elements in stars, and the nature of 
the red-shift, because they illustrate the unique powers of the 200- 
inch telescope in three aspects, namely, resolution, dispersion, and 
space penetration. 
Because these problems are of first importance, and can be solved, 
they, together with others of a similar kind, will be included in the 
initial research programs. The solutions of these problems alone 
will fully justify the construction of the telescope. 
But such a program is merely a logical beginning—the first carefully 
considered stage in the exploration of vast unknown regions of the 
universe. As the darkness is pushed back, greater problems will 
doubtless emerge which we cannot now foresee. 
FIRST PHOTOGRAPHS WITH THE 200-INCH HALE TELESCOPE? 
The first photographs with the 200-inch Hale reflector on Palomar, 
made under normal observing conditions, confirm the most optimistic 
predictions of its designers. Such a statement, as usual, requires some 
explanation. The photographs were made as routine tests to record 
progress in the tedious program of adjustments. Seeing was never 
better than “‘average,”’ the aluminum coat was dusty and grimy, and 
the mirror showed a turned-up edge. These handicaps, of course, 
2 A later article by Dr. Hubble from the Publications of the Astronomical Society of the Pacific, vol. 61, 
No. 360, June 1949, 
