449 



TABLE 463.— CALCULATED ATTENUATION OF MICROWAVES BY RAIN 



(db/km) *■ 



Wavelength (cm) 



Rate of rainfall , A , 



(mm/hr) 1.25 3 5 10 



2.46 193 db/km .049 .004 .0007 



6.0 (moderate) 615 .192 .012 .0017 



22.6 (heavy) 2.40 .728 .053 .0070 



43.1 (cloudburst) 6.17 1.64 .165 .016 



155 Adapted from article by L. Goldstein in Summary Technical Report of the National Defense 

 Research Committee, Committee on Propagation, vol. 2, p. 164, published by Academic Press. 



TABLE 464.— ATTENUATION OF MILLIMETER WAVES BY ATMOSPHERIC 



OXYGEN (db/km) 1S6 



156 Lamont, H. R., Proc. Phys. Soc. London, vol. 61, p. 562, 1948. 



TABLE 465.— EXTRATERRESTRIAL RADIO FREQUENCY RADIATION* 

 Part 1. — Discrete sources 



Source a 8 Reported by 1ST 



Cygnus 20 h 00 m +43° Hey, Parsons, Phillips' 



Cygnus A 19 59 +41°41' Bolton" 



Cygnus 19 h 58 m 47 8 ±10 s +41°41'±7' Bolton and Stanley f 



Cygnus 19 h 56 n \5 + 39°50' Ryle and Smith d 



Cygnus 20 30 +38° Hey, Parsons, Phillips & 



Ursa Major 12 18.2 +58°00 Ryle and Smith* 



Taurus A 5 13 +28° Bolton' 



Taurus A 5 ,, 31" , 00»±30 s +22°01' Bolton, Stanley, Slee b 



Taurus A 5 31 20 ±30 -f22°02'±8' Bolton, Stanley h 



Cassiopeia 23 h 17 m .5 + 58°10' Ryle and Smith <» 



Possible sources 



Coma Berenices A. 



+20°30' 



Bolton' 



Hercules A 16 21 +15 Bolton' 



Virgo A 12 l, 28"'06 s ±37 s -fl2°41'±10' Bolton, Stanley, Slee b 



Centaurus A 13 22 20 ±60 -42°37'±8' Bolton, Stanley, Slee b 



* Prepared by C. R. Burrows. 

 157 For references, see p. 450. 



(continued) 



SMITHSONIAN PHYSICAL TABLES 



Remarks 



Approx. position; \«s5m. 



Uncertainty of position about 1°. 

 Observed on 100 Mc/s. 



Observed on 100, 60, 85, 200 



Mc/s. 



Observed on 80 Mc/s. 



Observed on 64 Mc/s; position 

 very uncertain. 



Observed on 80 Mc/s. 



Angular width < 30° ; uncertainty 

 of position about 1°. Observed 

 on 100 Mc/s. 



Intensity measured at 100 Mc/s. 



Observed on 100 Mc/s. 



Observed on 80 Mc/s. 



Obsered on 80 Mc/s. 



Angular width <15'; uncertainty 

 of position about 1°. Observed 

 on 100 Mc/s. 



Angular width <1°; uncertainty 

 of position about 1°. Observed 

 on 100 Mc/s. 



Intensity measured at 100 Mc/s. 



Intensity measured at 100 Mc/s. 



