Known time description  
   
 
========================

Double Time ranges : date from 01/01/1970 to 01/01/2100  
 
---------------------------------------------------------

-   seconds from 01/01/1970 00:00:00 : 0 to 4 102 488 000
-   milliseconds from 01/01/1970 00:00:00 : 0 to 4 102 488 000 000
    (ambiguity for the first 48days of 1970 with previous time format)
-   seconds from 01/01/0000 00:00:00 : 62 168 472 000 to 66 270 960 000
    (no ambiguity)
-   milliseconds from 01/01/0000 00:00:00 : 62 168 472 000 000 to 66 270
    960 000 000 (no ambiguity)
-   seconds from 01/01/2000 00:00:00 : - 946 728 000 to 3 155 760 000
    (TT2000)
-   milliseconds from 01/01/2000 00:00:00 : - 946 728 000 000 to 3 155
    760 000 000 (ambiguity with TT2000 in seconds?)

µs, ns, ps might also be needed for tt2000

Double (IEEE754)  
64bits  
min value: –1.7977E+308  
max value :1.7977E+308

Number of seconds per year = 60\*60\*24\*365.25 = 31 557 600  
Numbers for 100 years :  
3 155 760 000 s = 3.15576 e+9 s  
3 155 760 000 000 ms = 3.15576 e+12 ms  
3 155 760 000 000 000 µs = 3.15576 e+15 µs  
3 155 760 000 000 000 000 ns = 3.15576 e+18 ns  
3 155 760 000 000 000 000 000 ps = 3.15576 e+21 ps

Typical dynamics for a double seems to be 15 digits, after that we might
experiment precision loss.  
Recommendation is to store time in QLop as microseconds since Epoch
(01-01-1970 00:00:00)

   
 

Known time description  
 
------------------------

|*.Mission Name |*.time var name |*. units |*.DEPEND
|*.LABLAXIS|*.FIELDNAM |*.CATDESC |*.Type |*.VIRTUAL|*.nb of
records|\_.VAR\_NOTES|  
|Cluster FGM |time\_tags\_\_CDFNAME |ms |0 |UT |Universal Time |Interval
centred time tag |CDF\_EPOCH | |normal |field missing|  
|Cluster HIA |time\_tags\_\_CDFNAME |ms |0 |UT |Center Time |Interval
centred time tag |CDF\_EPOCH | |normal |field missing|  
||||||||||||  
|Themis Efi,SCM |VARNAME\_time |sec |TIME |UT |Same as time var
name|UTC, in seconds sinc 01-Jan-1970 00:00:00|CDF\_DOUBLE | |normal
|Unleaped seconds|  
|Themis Efi,SCM |VARNAME\_epoch |field missing|0 |UT |Same as time var
name|Unrelated |CDF\_EPOCH |true |0 |field missing|  
|Themis Efi,SCM |VARNAME\_dot0\_epoch0|msec