Interpreting an FTPdetectinfo File - markmac99/ukmon-pitools GitHub Wiki

The FTPdetectinfo file created each night is one of the two key scientific data files, the other being the platepars_all file. What does it contain?

Header

The first eleven lines of the file are the header.

  • The first line indicates how many detections were made.
  • The next few are information about the processing run.
  • Line 10 tells you the information stored in the 3rd line of each detection segment.
Cam# Meteor# #Segments fps hnr mle bin Pix/fm Rho Phi
  • Line 11 tells you the columns of positional data stored in each detection segment.
Per segment: Frame# Col Row RA Dec Azim Elev Inten Mag

Detection segments

The file then contains zero or more detection segments.

  • Each detection segment begins with a line of dashes followed by the name of the FF file containing the detection. There may be more than one detection per FF file and if so, each will have its own segment.
  • The next line tells you if and when the data was recalibrated. If this line says "uncalibrated" then RMS could not use the platepar and you should probably check that it is still valid.
  • Next comes a header containing the information outlined in line 10 of the header. The most interesting field is the third one, which tells you how many frames contained a detection.
UK0006 0001 0012 0025.00 000.0 000.0 00.0 001.4 0125.0 -122.0

Detection lines

Each detection segment then contains one line per frame that contained a detection, something like this (I've pasted the header detals from line 11 so you can see what each column is) : 

Frame#   Col     Row     RA       Dec      Azim     Elev     Inten  Mag
227.7806 0718.00 0562.00 256.9827 +10.2149 243.7352 +31.4084 000138 4.50
    • Frame Number You'll notice that the Frame number is fractional. This is one of the smart features of RMS. The cameras we're using have an electronic rolling shutter - each row of pixels is read in turn starting from one corner of the sensor. The camera operates at 25 fps (thats field 4 in the header line 10), and has 720 lines to scan (thats in the .config file). RMS knows which scan line the detection was in (thats the row value), and so can work out the time of the event to the nearest 1/25/720th = 1/18000 of a second.
    • By the way, this is why you must not turn the camera upside down then use the "flip" function to invert the view. The sensor will be scanned in the same direction, but RMS will *think* that the opposite corner is row zero, and so all the timings will be incorrect by up to 1/25th of a second per frame. This is enough to break trajectory solving.
    • Row and Col identify the pixel of the brightest part of the detection in this frame (the centroid).
    • RA and Dec, Azim and Elev are the coordinates as seen from this camera. If these values are zero, it means that RMS could not apply the platepar.
    • Inten is the total intensity of pixels within a certain range of the centroid. This is used to calculate magnitude.
    • Mag is then derived from the intensity, by comparing it to the intensity of stars in the field of view whose magnitudes are known from the star catalogue. This allows RMS to compensate for cloud, moonlight and other effects. 
Meteor Count = 000195
-----------------------------------------------------
Processed with RMS 1.0 20211029_210240 083ede9405ccd3d707b88424d1059e8de7050024 on 2021-11-03 06:57:30.273606 UTC
-----------------------------------------------------
FF  folder = /home/pi/RMS_data/CapturedFiles/UK0006_20211102_170957_919661
CAL folder = /home/pi/RMS_data/CapturedFiles/UK0006_20211102_170957_919661
-----------------------------------------------------
FF  file processed
CAL file processed
Cam# Meteor# #Segments fps hnr mle bin Pix/fm Rho Phi
Per segment:  Frame# Col Row RA Dec Azim Elev Inten Mag
-------------------------------------------------------
FF_UK0006_20211102_174919_056_0058880.fits
Recalibrated with RMS on: 2021-11-03 06:57:30.139456 UTC
UK0006 0001 0012 0025.00 000.0 000.0  00.0 001.4 0125.0 -122.0
227.7806 0718.00 0562.00 256.9827 +10.2149 243.7352 +31.4084 000138 4.50
228.7778 0721.00 0560.00 256.8730 +10.4158 243.9729 +31.5132 000138 4.51
229.7806 0720.00 0562.00 256.8669 +10.2734 243.8845 +31.3922 000136 4.52
230.7763 0721.58 0558.97 256.8727 +10.4911 244.0234 +31.5749 101121 -2.66
231.7784 0723.43 0560.48 256.7168 +10.4597 244.1509 +31.4620 000275 3.76
232.7792 0724.00 0561.00 256.6671 +10.4469 244.1898 +31.4237 000136 4.52
233.7796 0728.54 0561.33 256.3923 +10.5605 244.5261 +31.3638 001913 1.65
234.7764 0729.00 0559.00 256.4405 +10.7058 244.5775 +31.5101 000136 4.52
235.7754 0728.32 0558.31 256.5024 +10.7251 244.5318 +31.5605 000415 3.31
236.7778 0729.00 0560.00 256.4087 +10.6492 244.5701 +31.4456 000136 4.52
237.7789 0732.50 0560.82 256.1784 +10.7044 244.8250 +31.3620 004872 0.63
238.7778 0733.00 0560.00 256.1757 +10.7654 244.8685 +31.4105 000690 2.75
-------------------------------------------------------
FF_UK0006_20211102_174929_294_0059136.fits

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