X-RAYS FROM THE SUN — FRIEDMAN 



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NNa62F. 



LEGEND 



CORONAL GREEN LINE OBSERVATIONS 

 CORONAL RED LINE OBSERVATIONS 

 CORONAL YELLOW LINE OBSERVATIONS 

 PLAGE REGION 

 INTENSE PLAGE REGION 

 DARK FILAMENT 

 PROMfNENCES ON SUN'S LIMB 



Figure 2. — Solar-activity map on day of rocket eclipse experiment, October 12, 1958. 



A strong correlation is known to exist between visible plage regions 

 and the regions of origin of the slowly varying component of radio 

 microwave emission. Solar radio emissions in the decimeter wave- 

 length range also correlate closely with variations in E-region elec- 

 tron density. The lower right-hand portion of figure 3 contains a 

 radioheliograph of the sun at a wavelength of 9.1 cm., obtained at 

 Stanford University with a microsteradian, pencil-beam interferom- 

 eter, having a resolution of 3.5 minutes of arc. It is interesting to 

 compare the radioheliograph with the X-ray disk photograph be- 



