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Radio Astronomy in my backyard: observing the Spiral arms of our Galaxy at 1.42 GHz H-line emission, 





    
        

            Wanni

Radio Astronomy in my backyard: observing the Spiral arms of our Galaxy at 1.42 GHz H-line emission

Description

This is my little Radio Astronomy experiment getting first results.

Original: drift scan waterfall diagram over > 24 hours
(quarterly hour-, hour- and UTC 00:00- marks at the very right vertical line)

AZ 180°, EL 50° resulting to Galactic longitudes 46° and 198°
(The Waterfall diagram starts at the top of the page, close to 198° Galactic longitude)
Center frequency is 1.420405 GHz, Bandwidth 1 MHz

We can see the different frequency spreadings of the Milkyway arms at GL 46° inwards and GL 198° outward ( in opposite to the galactic center)
Main features are the milky way Perseus arm plus our local Orion arm, at 46° also the faint outer arm at maximum blue shift frequency
( frequency distribution : H line rest frequency at center, blue shift right, redshift left
1.420405 GHz +/- 500 Mhz)

I am now running tests over Galactic longitudes from 0° to 230° to get a complete picture
of the Milkyway spiral arms . The Galactic longitudes > 230° are not visible at my latitude

The whole system is based on a low cost approach using
SDR dongle, Raspberry Pi processor,
two LNA's (0.6 dB noise figure) and a modified cavity filter,
originally used for Ham Radio(1.296 GHz)

The software for controlling and displaying a live Waterfall is based on an open source
FFT program where I added my algorithm for frequency switching and data processing /
display ( written in Python language)

P.S. Hint : Here a link to a very good video about the hydrogen line measurement and background
by JJ Maintoux "https://www.youtube.com/watch?v=HGwkZY4E64k" which inspired me a lot!

Comments

Author

wanni60
Wanni
License: None (All rights reserved)
2517
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Revisions

  • Radio Astronomy in my backyard: observing the Spiral arms of our Galaxy at 1.42 GHz H-line emission, 





    
        

            Wanni
    Original
  • Radio Astronomy in my backyard: observing the Spiral arms of our Galaxy at 1.42 GHz H-line emission, 





    
        

            Wanni
    B
  • Radio Astronomy in my backyard: observing the Spiral arms of our Galaxy at 1.42 GHz H-line emission, 





    
        

            Wanni
    C
  • Final
    Radio Astronomy in my backyard: observing the Spiral arms of our Galaxy at 1.42 GHz H-line emission, 





    
        

            Wanni
    D

B

homebrew 1.4204 GHz feed using double quad antenna array

C

Dish sideview

D

2.4 meter parabolic antenna next to my optical observational dome

Histogram

Radio Astronomy in my backyard: observing the Spiral arms of our Galaxy at 1.42 GHz H-line emission, 





    
        

            Wanni