A “strange” unit radio astronomy












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$begingroup$


I'm reading up on radio astronomy, and I came across this paper from 1964. At the bottom of page 193, the author uses a unit that I've not seen before in discussing radio power emission from stars:




Now the outbursts on the Sun give an intensity on Earth of $10^{19}$ to $10^{20}$ $wm^{-2}(c/s)^{-1}$




I'm guessing it's "Watts per square meter per something per second", but I'm not sure what the something is.



A similar unit appears in this paper on the first line on page 364:




The comparison band in the radiometer, being separated approximately 3.25 Mc from the signal band, never encounters the hydrogen range of frequencies.




Again, this looks to me like megasomething. Can anyone shed some light on this?



On page 362 of the second paper, the unit appears as $(Watts/M^2
)/(C/S)$ as a unit of flux. There, the $C$ looks like coulombs, but that makes the $3.25 Mc$ in the second quote seem weird.






radio-astronomy units







share|improve this question











$endgroup$

















    2












    $begingroup$


    I'm reading up on radio astronomy, and I came across this paper from 1964. At the bottom of page 193, the author uses a unit that I've not seen before in discussing radio power emission from stars:




    Now the outbursts on the Sun give an intensity on Earth of $10^{19}$ to $10^{20}$ $wm^{-2}(c/s)^{-1}$




    I'm guessing it's "Watts per square meter per something per second", but I'm not sure what the something is.



    A similar unit appears in this paper on the first line on page 364:




    The comparison band in the radiometer, being separated approximately 3.25 Mc from the signal band, never encounters the hydrogen range of frequencies.




    Again, this looks to me like megasomething. Can anyone shed some light on this?



    On page 362 of the second paper, the unit appears as $(Watts/M^2
    )/(C/S)$     as a unit of flux. There, the $C$ looks like coulombs, but that makes the $3.25 Mc$ in the second quote seem weird.






    radio-astronomy units







    share|improve this question











    $endgroup$















      2












      2








      2





      $begingroup$


      I'm reading up on radio astronomy, and I came across this paper from 1964. At the bottom of page 193, the author uses a unit that I've not seen before in discussing radio power emission from stars:




      Now the outbursts on the Sun give an intensity on Earth of $10^{19}$ to $10^{20}$ $wm^{-2}(c/s)^{-1}$




      I'm guessing it's "Watts per square meter per something per second", but I'm not sure what the something is.



      A similar unit appears in this paper on the first line on page 364:




      The comparison band in the radiometer, being separated approximately 3.25 Mc from the signal band, never encounters the hydrogen range of frequencies.




      Again, this looks to me like megasomething. Can anyone shed some light on this?



      On page 362 of the second paper, the unit appears as $(Watts/M^2
      )/(C/S)$       as a unit of flux. There, the $C$ looks like coulombs, but that makes the $3.25 Mc$ in the second quote seem weird.






      radio-astronomy units







      share|improve this question











      $endgroup$




      I'm reading up on radio astronomy, and I came across this paper from 1964. At the bottom of page 193, the author uses a unit that I've not seen before in discussing radio power emission from stars:




      Now the outbursts on the Sun give an intensity on Earth of $10^{19}$ to $10^{20}$ $wm^{-2}(c/s)^{-1}$




      I'm guessing it's "Watts per square meter per something per second", but I'm not sure what the something is.



      A similar unit appears in this paper on the first line on page 364:




      The comparison band in the radiometer, being separated approximately 3.25 Mc from the signal band, never encounters the hydrogen range of frequencies.




      Again, this looks to me like megasomething. Can anyone shed some light on this?



      On page 362 of the second paper, the unit appears as $(Watts/M^2
      )/(C/S)$       as a unit of flux. There, the $C$ looks like coulombs, but that makes the $3.25 Mc$ in the second quote seem weird.






      radio-astronomy units




      radio-astronomy units






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      share|improve this question




      share|improve this question








      edited 6 hours ago







      Jim421616

















      asked 6 hours ago









      Jim421616Jim421616

      574211




      574211






















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          $begingroup$

          I would expect the authors to be talking about the signal in terms of janskys, the now-commonly-used units of flux density. The typical definition is
          $$1text{ Jansky}=10^{-26}text{ Watts meters}^{-2}text{ Hertz}^{-1}$$
          One Hertz is one cycle per second, which makes me suspect that the "c" stands for cycle. It might seem curious that the authors choose to use cycles/second instead of Hertz, but as the papers were published in 1964 and 1955, and the Hertz was only adopted on a large scale in 1964, the older term "cycles per second" is more fitting, given the time period.






          share|improve this answer











          $endgroup$









          • 2




            $begingroup$
            The fact that they are from older papers makes me agree with you, that it's an old convention. Jansky is consistent with flux. Thanks!
            $endgroup$
            – Jim421616
            6 hours ago






          • 2




            $begingroup$
            I hadn't seen c/s before, but cps (cycles per second) was certainly a common abbreviation back in the olden days (and people would commonly refer to radio frequencies in units of kilocycles and megacycles, dropping the "seconds" entirely). When the SI was introduced in 1960, everyone standardised on Hz (even in the US!)
            $endgroup$
            – Michael MacAskill
            1 hour ago








          • 1




            $begingroup$
            @MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
            $endgroup$
            – HDE 226868♦
            51 mins ago













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          1 Answer
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          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          5












          $begingroup$

          I would expect the authors to be talking about the signal in terms of janskys, the now-commonly-used units of flux density. The typical definition is
          $$1text{ Jansky}=10^{-26}text{ Watts meters}^{-2}text{ Hertz}^{-1}$$
          One Hertz is one cycle per second, which makes me suspect that the "c" stands for cycle. It might seem curious that the authors choose to use cycles/second instead of Hertz, but as the papers were published in 1964 and 1955, and the Hertz was only adopted on a large scale in 1964, the older term "cycles per second" is more fitting, given the time period.






          share|improve this answer











          $endgroup$









          • 2




            $begingroup$
            The fact that they are from older papers makes me agree with you, that it's an old convention. Jansky is consistent with flux. Thanks!
            $endgroup$
            – Jim421616
            6 hours ago






          • 2




            $begingroup$
            I hadn't seen c/s before, but cps (cycles per second) was certainly a common abbreviation back in the olden days (and people would commonly refer to radio frequencies in units of kilocycles and megacycles, dropping the "seconds" entirely). When the SI was introduced in 1960, everyone standardised on Hz (even in the US!)
            $endgroup$
            – Michael MacAskill
            1 hour ago








          • 1




            $begingroup$
            @MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
            $endgroup$
            – HDE 226868♦
            51 mins ago


















          5












          $begingroup$

          I would expect the authors to be talking about the signal in terms of janskys, the now-commonly-used units of flux density. The typical definition is
          $$1text{ Jansky}=10^{-26}text{ Watts meters}^{-2}text{ Hertz}^{-1}$$
          One Hertz is one cycle per second, which makes me suspect that the "c" stands for cycle. It might seem curious that the authors choose to use cycles/second instead of Hertz, but as the papers were published in 1964 and 1955, and the Hertz was only adopted on a large scale in 1964, the older term "cycles per second" is more fitting, given the time period.






          share|improve this answer











          $endgroup$









          • 2




            $begingroup$
            The fact that they are from older papers makes me agree with you, that it's an old convention. Jansky is consistent with flux. Thanks!
            $endgroup$
            – Jim421616
            6 hours ago






          • 2




            $begingroup$
            I hadn't seen c/s before, but cps (cycles per second) was certainly a common abbreviation back in the olden days (and people would commonly refer to radio frequencies in units of kilocycles and megacycles, dropping the "seconds" entirely). When the SI was introduced in 1960, everyone standardised on Hz (even in the US!)
            $endgroup$
            – Michael MacAskill
            1 hour ago








          • 1




            $begingroup$
            @MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
            $endgroup$
            – HDE 226868♦
            51 mins ago
















          5












          5








          5





          $begingroup$

          I would expect the authors to be talking about the signal in terms of janskys, the now-commonly-used units of flux density. The typical definition is
          $$1text{ Jansky}=10^{-26}text{ Watts meters}^{-2}text{ Hertz}^{-1}$$
          One Hertz is one cycle per second, which makes me suspect that the "c" stands for cycle. It might seem curious that the authors choose to use cycles/second instead of Hertz, but as the papers were published in 1964 and 1955, and the Hertz was only adopted on a large scale in 1964, the older term "cycles per second" is more fitting, given the time period.






          share|improve this answer











          $endgroup$



          I would expect the authors to be talking about the signal in terms of janskys, the now-commonly-used units of flux density. The typical definition is
          $$1text{ Jansky}=10^{-26}text{ Watts meters}^{-2}text{ Hertz}^{-1}$$
          One Hertz is one cycle per second, which makes me suspect that the "c" stands for cycle. It might seem curious that the authors choose to use cycles/second instead of Hertz, but as the papers were published in 1964 and 1955, and the Hertz was only adopted on a large scale in 1964, the older term "cycles per second" is more fitting, given the time period.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited 49 mins ago

























          answered 6 hours ago









          HDE 226868♦HDE 226868

          20k265125




          20k265125








          • 2




            $begingroup$
            The fact that they are from older papers makes me agree with you, that it's an old convention. Jansky is consistent with flux. Thanks!
            $endgroup$
            – Jim421616
            6 hours ago






          • 2




            $begingroup$
            I hadn't seen c/s before, but cps (cycles per second) was certainly a common abbreviation back in the olden days (and people would commonly refer to radio frequencies in units of kilocycles and megacycles, dropping the "seconds" entirely). When the SI was introduced in 1960, everyone standardised on Hz (even in the US!)
            $endgroup$
            – Michael MacAskill
            1 hour ago








          • 1




            $begingroup$
            @MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
            $endgroup$
            – HDE 226868♦
            51 mins ago
















          • 2




            $begingroup$
            The fact that they are from older papers makes me agree with you, that it's an old convention. Jansky is consistent with flux. Thanks!
            $endgroup$
            – Jim421616
            6 hours ago






          • 2




            $begingroup$
            I hadn't seen c/s before, but cps (cycles per second) was certainly a common abbreviation back in the olden days (and people would commonly refer to radio frequencies in units of kilocycles and megacycles, dropping the "seconds" entirely). When the SI was introduced in 1960, everyone standardised on Hz (even in the US!)
            $endgroup$
            – Michael MacAskill
            1 hour ago








          • 1




            $begingroup$
            @MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
            $endgroup$
            – HDE 226868♦
            51 mins ago










          2




          2




          $begingroup$
          The fact that they are from older papers makes me agree with you, that it's an old convention. Jansky is consistent with flux. Thanks!
          $endgroup$
          – Jim421616
          6 hours ago




          $begingroup$
          The fact that they are from older papers makes me agree with you, that it's an old convention. Jansky is consistent with flux. Thanks!
          $endgroup$
          – Jim421616
          6 hours ago




          2




          2




          $begingroup$
          I hadn't seen c/s before, but cps (cycles per second) was certainly a common abbreviation back in the olden days (and people would commonly refer to radio frequencies in units of kilocycles and megacycles, dropping the "seconds" entirely). When the SI was introduced in 1960, everyone standardised on Hz (even in the US!)
          $endgroup$
          – Michael MacAskill
          1 hour ago






          $begingroup$
          I hadn't seen c/s before, but cps (cycles per second) was certainly a common abbreviation back in the olden days (and people would commonly refer to radio frequencies in units of kilocycles and megacycles, dropping the "seconds" entirely). When the SI was introduced in 1960, everyone standardised on Hz (even in the US!)
          $endgroup$
          – Michael MacAskill
          1 hour ago






          1




          1




          $begingroup$
          @MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
          $endgroup$
          – HDE 226868♦
          51 mins ago






          $begingroup$
          @MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
          $endgroup$
          – HDE 226868♦
          51 mins ago




















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