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21-03-06, 11:58 PM
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| 122cm target faces Does anyone know the actual reason target face is 122cm? Doing some calculations today, I think I may have hit upon a possible reason for it. But I'd like to know if it is right or if it is just mere (and very strange) coincidence.      |
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22-03-06, 12:05 AM
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| I believe the size was originally directly metricised ( is that a word?) from the old 4 foot British standard target face. Strange that it was never rounded down by FITA though now we have 80, 60 and 40 cm faces for other rounds/distances.
__________________ The more I practice, the luckier I seem to get. | ||||||||||||||||||||||||||
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22-03-06, 12:08 AM
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| its not summing to do with the relative area of each segment is it???
__________________ grab a fist full of bow, a hand full of arrow and keep fighting. | ||||||||||||||||||||||||
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22-03-06, 12:37 AM
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| Quote:
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22-03-06, 08:37 AM
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| Okay, then it is mere coincidence. I was trying to find the viewing angle relationship between the 11.5m I shoot in my back garden, 18m indoors and 70m outdoors. 11.5m turns out to be a good number to work with because it the X-ring (at 2cm) at that distance is exactly 1/10º in our field of view and the entire target face (at 40cm) is 2º. Relating this to 70m, the 122cm target face we shoot at is exactly (to within 2mm) 1º in our field of view. 140m x pi = 439.82 439.82 / 360º = 1.2217m =122.17cm Quite a handy number to work with, if you ask me.  |
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22-03-06, 10:36 AM
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| Someone either a) has become delirious after the exetrions of the last two weekends or b) has too much time on their hands. It's the 4 foot explanation I'm afraid. (Though, of course, the question is now why 4 foot? And did someone do Grant's calculations to determine other target sizes/distances?)
__________________ If - Kipling | ||||||||||||||||||||||||||
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22-03-06, 10:59 AM
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| I just wonder Grant if you've come up with the mathematical reason for several hundred years' evolution of 'that looks about right.'  | |||||||||||||||||||||||||||
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22-03-06, 11:29 AM
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| I think the problem justifying it is that the metric system (and therefore shooting at 70m) hasn't been around for several hundred years. 80y would require a 127cm target face to be one degree at that distance. Not too far off, I suppose... |
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22-03-06, 11:28 PM
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| Within the accuracy of the period these sizes were set I doubt anyone was too fussed about 2" at 80yd. (Anyway, what are 80cm faces at 30m in comparison??)
__________________ Brain, n: An apparatus with which we think that we think. -Ambrose Bierce  |
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22-03-06, 11:37 PM
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| A lot closer?? 
__________________ Purple Mafia  Luck is what you have left over after you give 100% | |||||||||||||||||||||||||||||
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