File:Wow signal spectrogram.svg

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Summary

Description
English: Spectrogram of the "Wow! signal", taken from the intensities of the printout, with axes etc described in http://www.bigear.org/Wow30th/wow30th.htm Data hand-copied from http://www.bigear.org/Wow30th/WowL.jpg (by resizing it to same resolution as translucent text editor)
Date
Source Own work
Author Omegatron
SVG development
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Source code
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Python code

Source code
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
from matplotlib.ticker import AutoMinorLocator
import datetime as dt

# "A space character on the printout denotes an intensity between 0 and 1"
d = {' ': 0}

# 'the numbers "1" to "9" denote the correspondingly numbered intensities'
for n in range(1, 10):
    d.update({str(n): n})

# 'intensities of 10 and above are indicated by a letter:
# "A" corresponds to intensities between 10 and 11,
# "B" to 11 to 12, and so on. The highest measured value was "U" (an intensity
# between 30 and 31), that is thirty times stronger than normal background
# noise.'
for n in range(10, 36):
    d.update({chr(65-10+n): n})

data = np.ones((82, 50), dtype=int)
with open('wow signal.txt', 'r') as f:
    for x, line in enumerate(f.readlines()[4:]):
        for y, c in enumerate(line[:50].strip('\n').ljust(50)):
            data[x, y] = d[c]

x_lims = [0.5, 50.5]  # Bin centers align with channel numbers

# August 15, 1977, Start: 22:04:10, Peak:  22:16:10, Stop:  22:20:21
# "Also, the EST on the printout referred to the end of the integration
# interval rather than the middle of that interval."
# So the center of each bin corresponds to these times - 5 seconds
y_lims = [dt.datetime(1977, 8, 15, 22, 20, 21-5),
          dt.datetime(1977, 8, 15, 22,  4, 10-5)]
y_lims = mdates.date2num(y_lims)

plt.figure(figsize=(5, 6))
plt.imshow(data, cmap='YlGnBu_r', aspect='auto',
           extent=[x_lims[0], x_lims[1],  y_lims[0], y_lims[1]])
cbar = plt.colorbar()
cbar.set_label('SNR')

ax = plt.gca()
ax.yaxis_date()
date_format = mdates.DateFormatter('%H:%M:%S')
ax.yaxis.set_major_formatter(date_format)
plt.yticks([dt.datetime(1977, 8, 15, 22, 6, 00),
            dt.datetime(1977, 8, 15, 22, 8, 00),
            dt.datetime(1977, 8, 15, 22, 10, 00),
            dt.datetime(1977, 8, 15, 22, 12, 00),
            dt.datetime(1977, 8, 15, 22, 14, 00),
            dt.datetime(1977, 8, 15, 22, 16, 00),
            dt.datetime(1977, 8, 15, 22, 18, 00),
            dt.datetime(1977, 8, 15, 22, 20, 00)])

plt.minorticks_on()
ax.yaxis.set_minor_locator(AutoMinorLocator(4))

plt.xlabel('Channel number')
plt.ylabel('EST [HH:MM:SS]')
plt.tight_layout()

Data

wow signal.txt
CHANNEL NUMBER.(TWO DIGITS, WRITTEN VERTICALLY),  C RT. ASCEN.  DECLIN.   2ND LO   GLCTIC  GLCTIC  EASTERN    OBJECT
00000000011111111112222222222333333333344444444445 N  (1950.0)  (1950.0)    FREQ.    LAT     LONG   STD TIME
12345678901234567890123456789012345678901234567890 T  HH MM SS    DD MM    (MHz.)   (DEG.)  (DEG.)  HH MM SS

   2     1       1        1    21  1 1        1       19 05 22  - 27 02    120.162  -15.39   10.13  22 04 10
   1  21    1     12 1 11 1    11 1  1 1              19 05 37  - 27 02    120.163  -15.44   10.16  22 04 25
   1  1     1  2 1 1 1 1    11 1111   1      1        19 05 49  - 27 02    120.163  -15.45   10.18  22 04 37
  2 1    1        1    1  11 11  1   1                [too lazy to finish this part]
 12    1   1   1       1      1111   1
    1  1     1 11 1  1 1   1   111211
   12 21    1  21    1 1 1     11 21      2    1
   2  21    1  2 111   11       1 2 1        1
      21             11   1    11221  1      1
    1 2      1   1  1     11     11   1   1
  11  2       1   2       11 11112     1     1   1
 1  1 11       111 2  1 1  1    111    1       1
  2    1    1      1      11  1111   1 1        11
  12  1                                  1
    1          1  11             11  1 1  1 11 1 1
       1     2   113  1               1
  1  111       111   1 2   1    11  1  1    11 1
   1 11        1  2              1           1
   11 21  1 1  1                  1     2  1     1
12  1  1 41 2  211 1   1  1    1         1  1
  221        1 11 11  11           1  11 1       1
  312    1                1        11  1     1
1  3     1  1    122   1  1   1   1   1     1
1 31  41     1     2   1      1  1111
  12212        1   1    1     1 12
   21 23     1 1 1 1     1        21      1  1
  6 3 1    111       1  11 1    2 1   1 1   2
   11       1  1   1        11              1   1
  211          2   2    1 1   1
  211 11    2  1 11       1   1111   11
 12   11 1  2 11  2111 1  1    12 1              1
 21         1  111        1  1 1      1     1  1
   1        11 211    111 1   1  112 11  1       1
   1  1     1  2       11     211 21  1
   21  1    1  1   2      1   111  11 1
  1         1  11111            1    1  1
  212             1              1  2
        1   1  2  11 11   1    1 1111111 2
  2   11    11     1  1          1 111       1 1
 1 11          1  111         1    111     111
  1111  111    1   1  1     1      112      11
               1     1 1 1      22  211 22 111
      1        1 1 1               2121 313 21
  11 13 1          2  11            111 22211 11
  11  2        1   2            1   11       1
   11 3        1 15             11  21     1  1
1 111 11    1                11 11         1
      1                    2      1   1     11 2
1  2           1  21 2            1111      1 1  1
1 12     1        1   11  1   1   1 21   1     1
 11   12  1   1111112                1     211  1
   2  1   1  1 1     11       1  11 1      1112 1
   21 1         121  1 1      1   1   1  22 21  1
1     2        1  4  32 1    1   2    2 1 1      1
1 16  1      1     1    11 13  1 11   111   1 1 11
1 11  1    1      11 1        1  1        1     1
  1            3   1             1 1       1 2   1
 6 2           31      1  2 11 1         3111221 1
1E24  3  12  1 21 1         1 3  1 1     3 1 11 1
 Q 1 16 1 2  1  1    1               11 11  1 1
 U31  1      3 7  1              1    2  11    1
2J1   31 3 111  11 1 12       2 12  2 1 2111 11211
 51            1  1           1 1   1   121   1 1
  14   1   113   2  111        11   1   1111111
 1 3  1   1    1       11 1        1  1 12 112  1
 1 4      1  1 1  11  2       11  1   1 111 11
   4  1 1  1 11   111         12 1    1  1211 1
   1        1    2 1               11    1   2 11
 1 1  1        11  1      1    1 1      3 2
   1      1       14    11        1 1     3 1 21 1
1  1  1        2    1   1 1       11   11112  1 1
   11 2    1 1 3   1    1    1   1 11   2 11    1
1  1           1 1   1    11  1  1111 2     11
2     3      1 3 11              1111   11   11
2  3  4 1  1   1        1 1   1     1   1 2 111 1
      1           11            1  112    1   11
     12 1 1       111     1 21 2   111     1   211
 2    5    1 1  1     2      1    1 11  1 2 1    1
 1 2  1        1   1   1    1  1  112     1 1
   1  1     1         11       11  1 11
   1      1    2              2  1 12     2  2 1
2  3  1    2   1 1  1      11     11111    1

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