A “strange” unit radio astronomy
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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 mega[something]. 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
edited Mar 5 at 8:57
Wrigglenite
1097
asked Mar 4 at 22:16
Jim421616Jim421616
675214
$endgroup$
add a comment |
$begingroup$
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 mega[something]. 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
edited Mar 5 at 8:57
Wrigglenite
1097
asked Mar 4 at 22:16
Jim421616Jim421616
675214
$endgroup$
add a comment |
$begingroup$
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 mega[something]. 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
edited Mar 5 at 8:57
Wrigglenite
1097
asked Mar 4 at 22:16
Jim421616Jim421616
675214
$endgroup$
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 mega[something]. 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
edited Mar 5 at 8:57
Wrigglenite
1097
asked Mar 4 at 22:16
Jim421616Jim421616
675214
edited Mar 5 at 8:57
Wrigglenite
1097
asked Mar 4 at 22:16
Jim421616Jim421616
675214
edited Mar 5 at 8:57
Wrigglenite
1097
edited Mar 5 at 8:57
Wrigglenite
1097
edited Mar 5 at 8:57
Wrigglenite
1097
1097
asked Mar 4 at 22:16
Jim421616Jim421616
675214
asked Mar 4 at 22:16
Jim421616Jim421616
675214
asked Mar 4 at 22:16
Jim421616Jim421616
675214
675214
add a comment |
add a comment |
1 Answer
1
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oldest
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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.
edited Mar 5 at 12:06
Mick
1,141323
answered Mar 4 at 22:37
HDE 226868♦HDE 226868
20.5k268128
$endgroup$
3
$begingroup$
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
Mar 4 at 22:38
5
$begingroup$
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
Mar 5 at 3:35
2
$begingroup$
@MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
$endgroup$
– HDE 226868♦
Mar 5 at 3:50
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The context of the second paper makes it clear that "Mc" is "megacycles [per second]".
$endgroup$
– Mark
Mar 5 at 20:16
add a comment |
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1 Answer
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active
oldest
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1 Answer
1
active
oldest
votes
active
oldest
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active
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votes
$begingroup$
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.
edited Mar 5 at 12:06
Mick
1,141323
answered Mar 4 at 22:37
HDE 226868♦HDE 226868
20.5k268128
$endgroup$
3
$begingroup$
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
Mar 4 at 22:38
5
$begingroup$
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
Mar 5 at 3:35
2
$begingroup$
@MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
$endgroup$
– HDE 226868♦
Mar 5 at 3:50
$begingroup$
The context of the second paper makes it clear that "Mc" is "megacycles [per second]".
$endgroup$
– Mark
Mar 5 at 20:16
add a comment |
$begingroup$
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.
edited Mar 5 at 12:06
Mick
1,141323
answered Mar 4 at 22:37
HDE 226868♦HDE 226868
20.5k268128
$endgroup$
3
$begingroup$
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
Mar 4 at 22:38
5
$begingroup$
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
Mar 5 at 3:35
2
$begingroup$
@MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
$endgroup$
– HDE 226868♦
Mar 5 at 3:50
$begingroup$
The context of the second paper makes it clear that "Mc" is "megacycles [per second]".
$endgroup$
– Mark
Mar 5 at 20:16
add a comment |
$begingroup$
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.
edited Mar 5 at 12:06
Mick
1,141323
answered Mar 4 at 22:37
HDE 226868♦HDE 226868
20.5k268128
$endgroup$
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.
edited Mar 5 at 12:06
Mick
1,141323
answered Mar 4 at 22:37
HDE 226868♦HDE 226868
20.5k268128
edited Mar 5 at 12:06
Mick
1,141323
edited Mar 5 at 12:06
Mick
1,141323
edited Mar 5 at 12:06
Mick
1,141323
1,141323
answered Mar 4 at 22:37
HDE 226868♦HDE 226868
20.5k268128
answered Mar 4 at 22:37
HDE 226868♦HDE 226868
20.5k268128
answered Mar 4 at 22:37
HDE 226868♦HDE 226868
20.5k268128
20.5k268128
3
$begingroup$
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
Mar 4 at 22:38
5
$begingroup$
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
Mar 5 at 3:35
2
$begingroup$
@MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
$endgroup$
– HDE 226868♦
Mar 5 at 3:50
$begingroup$
The context of the second paper makes it clear that "Mc" is "megacycles [per second]".
$endgroup$
– Mark
Mar 5 at 20:16
add a comment |
3
$begingroup$
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
Mar 4 at 22:38
5
$begingroup$
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
Mar 5 at 3:35
2
$begingroup$
@MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
$endgroup$
– HDE 226868♦
Mar 5 at 3:50
$begingroup$
The context of the second paper makes it clear that "Mc" is "megacycles [per second]".
$endgroup$
– Mark
Mar 5 at 20:16
3
3
$begingroup$
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
Mar 4 at 22:38
$begingroup$
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
Mar 4 at 22:38
5
5
$begingroup$
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
Mar 5 at 3:35
$begingroup$
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
Mar 5 at 3:35
2
2
$begingroup$
@MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
$endgroup$
– HDE 226868♦
Mar 5 at 3:50
$begingroup$
@MichaelMacAskill Yeah, considering when the Hertz was adopted makes the non-use of Hertz here make a lot more sense.
$endgroup$
– HDE 226868♦
Mar 5 at 3:50
$begingroup$
The context of the second paper makes it clear that "Mc" is "megacycles [per second]".
$endgroup$
– Mark
Mar 5 at 20:16
$begingroup$
The context of the second paper makes it clear that "Mc" is "megacycles [per second]".
$endgroup$
– Mark
Mar 5 at 20:16
add a comment |
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