Dawes' limit (DL)=116/a where DL is arc-sec, a is aperture (mm).
Dawes' limit (DL)=4.56/a where DL is arc-sec, a is aperture (in.).
Limiting visual magnitude (Lvm)=9+(5*(log(a))) where a is aperture (in.), and log is base 10.
"Plate" scale (ps)=8120.667/fl where ps is arc-sec/mm, fl is focal length in inches.
Pixel fov (s)=205(p/fl) where s is arc-sec, p is pixel size in microns, fl is focal length (mm).

Time correction (tc)=-[(sl)-(ol))*4] where tc is min., sl is standard longitude, ol is observer's longitude.
[example: Raton tc is -(105-104.4374)*4 = -2.25 minutes]

Wavelength (w)=2886/K where w is wavelength of maximum emission in microns, K is the temperature in Kelvin.
[10,000 Angstroms = 1 micron]

Temperature Celsius (tc) = tk - 273.15 where tk is the temperature in Kelvin.
Temperature Fahrenheit (tf) = ((9/5)*tc)+32 where tc is the temperature in Celsius.
Temperature Rankine (tr) = tf+459.7

WWV frequencies = 2.5, 5.0, 10.0, 15.0, 20.0 MHz (Ft. Collins, CO., USA).
CHU frequencies = 3.33, 7.335, 14.67 MHz (Ottawa, Canada).

ALPO seeing scale = 0 to 10, with 0=worst, 10=perfect.
ALPO transparency scale = 0 to 5, with 0=worst, 5=perfect.

1 nautical mile = 1.1508 statute miles
1 meter = 39.37008 inches
1 meter = 3.280840 feet
1 meter = 1.093613 yards

(Always under construction)

click here to see visual photometry & stellar brightness data