Getting UT/ST Zeropoint by Alternate Means.
Our program requires knowing the Universal Time and Siderial Time at a given instant. If you forgot to write this on your log sheet, here is alternate way to get it:
- Open SkyCalc tools webpage (thanks to John Thorstensen at Dartmouth College) and click "Daily Almanac"
- Enter the Year, Month, and Day (UT) in question
- For OBSERVATORY, select Other.
- Enter the Observatory's Longitude (in h m s) = 05 34 33
- Enter the Observatory's Latitute (in d ' ") = 41 22 47
- Enter the Observatory's Elevation (in meters, put it in Effective Elevation too): 225
- Enter Site Name = BGSU
- Enter Standard Time Zone, hours West = 5
- Enter Time Zone Name = eastern
- Enter Time Zone Abbrev = E
- Keep Daylight-Savings Option = U.S. Convention
- Click (Get Almanac) button.
Look down into the second block of text, the second & third lines should say:
- Local midnight = ......., 4 hr UT, or JD 245.... (if you are on daylight time, or it may say 5 hr UT if you are on standard time)
- Local Mean Sidereal Time at midnight = hh mm ss.s
In our headadd.cl program, enter as follows:
- UT at beginning of night: 04 00 00 (or 05 00 00 as appropriate to Local midnight above)
- ST at beginning of night: hh mm ss.s (from LMST above)
While you have the SkyCalc page up, you might also
write down the Julian date (JD), just to confirm that IRAF etc were
able to compute it correctly.
Updated 2006 Sep 15 -- ACL