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DATE parameter HJD in AAVSO report?

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DATE parameter HJD in AAVSO report?

I moved to use the program FotoDif, to make my measurements.

This is orginal Fotofif data:



   C1: 13.068

   C2: 13.37

UX UMA                                     CHK-135

GEO J DATE            MAG      +/-    NSR         MAG      +/-    NSR  AIRMS  TRANS  FWHM"   BAKGR   N   NUM

-----------------------------------------  --------------------------  -----  -----  -----  ------  --  ----

2456725.21170      12.909    0.009    121      13.509    0.012     92  2.399   1.06   3.83   16.79  01  0001

2456725.21219      12.900    0.009    122      13.520    0.012     92  2.398   1.07   3.98   16.87  01  0002


When make AAVSO report, FotoDif compute time only as Heliocentric Julian Date - HJD. Is that ok?

Below an example AAVSO report generated by the Fotodif - is it right?

Chart is 13186DYN, Filter Jhonson-V, two ref.stars (131 and 134) Chk star is 135.



#SOFTWARE=FotoDif 3.89





UX UMA,2456725.21496,12.909,0.009,V,NO,STD,ENSEMBLE,na,135,13.509,2.399,NA,13186DYN,na

UX UMA,2456725.21545,12.900,0.009,V,NO,STD,ENSEMBLE,na,135,13.520,2.398,NA,13186DYN,na

Reply to myself: DATE:

Reply to myself:

  • DATE: The format of the date used in the report. Times are midpoint of the observation. Convert all times from UT to one of the following formats:
    • JD: Julian Day (Ex: 2454101.7563)
    • HJD: Heliocentric Julian Day
    • EXCEL: the format created by Excel's NOW() function (Ex: 12/31/2007 12:59:59 a.m )

HQA's picture

Hi Timo,

As you already found out, the AAVSO Extended Format supports HJD.  I personally submit all of my data using that date format.  WebObs stores the HJD and then converts it to JD and also stores that value with each record (since the Light Curve Generator currently uses JD for its plots).  When someone downloads your observations, they will see the original HJD that you used for the submission.


SDB's picture
HJD from Fits header


Are you aware of any programs, hopefully Win, that will pick up the RA, Dec and JD from the image Fits header and output the HJD?



TCB168's picture
AIP4WIN will output HJD. You

AIP4WIN will output HJD. You just have to have told it lat and long in the settings.


HQA's picture
HJD calculations

Hi Donn,

I'm not a Windows person, so I hope someone steps forward with an answer for you!  There are several HJD calculators on the Web (and of course, IRAF has such utilities...), such as


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