Signal-to-Noise Calculator

#!/usr/bin/perl $Root = $ENV{'DOCUMENT_ROOT'}; chdir("$Root/code/snr"); $QueryString = $ENV{'QUERY_STRING'}; if ($QueryString) { open (MYFILE, '>input'); @NameValuePairs = split (/&/, $QueryString); foreach $NameValue (@NameValuePairs) { ($Name, $Value) = split (/=/, $NameValue); $Value =~ tr/+/_/; $Value =~ s/%([\dA-Fa-f][\dA-Fa-f])/ pack ("C", hex($1))/eg; if (!$Value) { break; $Incomplete = 1; } if ($Name ne "timeOrSnr") { print MYFILE "$Value\n"; $Stored[$index++] = $Value; } else { $TimeOrSnr = $Value; } } print MYFILE "$TimeOrSnr\n"; print MYFILE "0\n"; close (MYFILE); } print "Content-type: text/html\n\n"; print "\n\n"; print "\n"; print "Signal-to-Noise Calculator\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "

Signal-to-Noise Calculator

\n"; print "\n"; print "\n"; print "\n"; print "

\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "

\n"; print "k is the magnitude zero point. ADUs are computed using the GRIM II\n"; print "(mid-90s) value of 4.73 e^-/ADU.\n"; print "

\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "\n"; print "

\n"; print "\n"; print "	\n"; print " \n"; print "
\n"; print "object size (pixels) \n"; print "	\n"; print "\n"; print "
\n"; print "readout noise (e^-/pixel) \n"; print "	\n"; print "\n"; print "
\n"; print "k (phot/s/cm/cm/Å) \n"; print "	\n"; print "\n"; print "
\n"; print "object magnitude \n"; print "	\n"; print "\n"; print "
\n"; print "sky brightness (mag/arcsec²) \n"; print "	\n"; print "\n"; print "
\n"; print "filter bandwidth (Å) \n"; print "	\n"; print "\n"; print "
\n"; print "pixel area (arcsec²) \n"; print "	\n"; print "\n"; print "
\n"; print "system efficiency \n"; print "	\n"; print "\n"; print "
\n"; print "ND# (e^-/phot) \n"; print "	\n"; print "\n"; print "
\n"; print "telescope area (cm²) \n"; print "	\n"; print "\n"; print "
	\n"; print "\n"; print "

\n"; print "

\n"; print "\n"; if ($QueryString) { system("$Root/code/snr/snr < input > output"); open (MYFILE, "output"); for ($i = 0; $i < 7; $i++) { readline (MYFILE); } for ($i = 0; $i < 7; $i++) { $Out = readline (MYFILE); print "$Out
"; } close (MYFILE); unlink ("input"); unlink ("output"); } print "\n"; print "\n"; end; sub selected { if ($_[0] eq $_[1]) { return " selected" } return ""; }