You may want to post an example of exactly what you want to do.
To change the contents of a number fields such as your julian date field, you just use the + operator to add days and the - operater to subtract days.
If Julian Date field = 500
Julian Date field + 5 computes a julian date, 505, 5 days later and
Julian date field - 5 computes a julian date, 495, 5 days earlier.
Even convential fields of type date can be used to compute dates a specified number of days in the future or past by adding or subtracting days in the same fashion though they will display as convential dates instead of as a number.
Thank you for your post. What you said is what the manuals said, but I don't know how to do it. Where do I place the operation? Do I have to create another field?
That's why I asked for an example. It depends on what you need to do with the date. Such calculations can be used in scripts or in calculation fields. The calculations can use a constant such as the number 5 or you can refer to a value in another field to control the number of days to be added or subtracted.
In the scripting: Set Variable $myTempNewDate = MyFile::myDateField + 5
Thank you for your notes. Here is the example. I have data tied to certain dates. I have them listed with both Julian and Gregorian dates. I would like to see what data I have for some date (for example) 1,000 days ago. I have created a field for that information, but do not know how to perform the operation.
Thank you for your assistance!
Then you do not need a variable and a script nor do you even need julian dates though you can use them if they are useful to you.
Say you have a number field defined as DaysInPast. Then you can define this calculation field, cJulianPast, for the Julian Date:
JulianDateField - DaysInPast
Select Number as the return type.
You can use the gregorian date fields and compute a Gregorian date with a calculation field defined as:
GregorianDateFIeld - DaysInPast
Select Date as the return type.