[Difx-users] generate fixed JPLEPH calc9 file for calcif2? {External}

[David Gordon]

Maybe I can help here. I haven't looked at calc 9 in many years and don't
have a copy of it.
If someone can provide me a copy of calc9/calcif2 I will take a look at it.
The JPL ephemerises
are made using software and ascii files from a JPL web site. I forget which
JPL ephemeris is
used by calc9 - DE405 maybe? I can look to see if that can be extended, but
it's unlikely
since DE405 is obsolete. Difxcalc uses DE421, which expires in 2050, so it
will need to be
replaced sometime also. Probably the best quick fix would be to replace the
relevant subroutines
in calc9 with the ones used by difxcalc (in file cpepu.f), and then use
DE421. Some
parameters would also need to be changed. Another issue is I believe calc9
is Fortran77
while calc11 is Fortran90. Just renaming it cpepu.f90 might be enough
though for the compiler.

So, Jan, if you can send me calc9/calcif2 or where to get it, I will try to
work on this in the
next few days. Better to contact me at my USNO Email -
david.gordon126.civ at us.navy.mil.

Regards,
David


On Tue, Jan 21, 2025 at 4:28 PM Jay Blanchard via Difx-users <
difx-users at listmgr.nrao.edu> wrote:

> Sorry Jan I don't know enough about the formats but just in case it is the
> same - here is JPLEPH.421 that we use for SCHED.
> I assume it is not the same?
>
> On Tue, 21 Jan 2025 at 09:58, Michael Dutka via Difx-users <
> difx-users at listmgr.nrao.edu> wrote:
>
>> Hi Jan,
>> We just updated the tables dfixcalc11 uses with more stations they're
>> attached here.  Hope these help!
>> -Mike
>>
>>
>>
>> On Tue, Jan 21, 2025 at 9:49 AM Jan Wagner via Difx-users <
>> difx-users at listmgr.nrao.edu> wrote:
>>
>>> Hi list,
>>>
>>> the old CALC 9.1 model behind DiFX 'calcif2' comes with two data
>>> files, JPLEPH and Horizons.lis.
>>>
>>> Unfortunately, the file JPLEPH file is "broken" in the sense that the
>>> ephemerides data contained in it ended already on 12th January 2025.
>>>
>>> For VLBI experiments after that date, the calcif2 processing needed
>>> prior to correlation does not work - not even for VLBI experiments without
>>> local planetary objects.
>>>
>>> Perhaps someone on the list would be able to generate a corrected file?
>>>
>>> John Benson created the current file at NRAO more than 10 years ago.
>>> Unfortunately, he is not at NRAO anymore, perhaps retired.
>>>
>>> A move to difxcalc11 to replace calcif2 is possible, but the ocean
>>> loading tables in it are incomplete. They are missing a lot of stations,
>>> difxcalc11 complains. It'd be more convenient if calcif2 could work for a
>>> while longer - with a fixed JPLEPH file.
>>>
>>> Many thanks,
>>> kind regards,
>>> Jan
>>> _______________________________________________
>>> Difx-users mailing list
>>> Difx-users at listmgr.nrao.edu
>>> https://listmgr.nrao.edu/mailman/listinfo/difx-users
>>>
>>
>>
>> --
>> Dr. Michael S. Dutka
>> US Navy (civilian)
>> USNO Phone Number- 202-762-0242
>> Cell- 301-996-3588
>>
>> _______________________________________________
>> Difx-users mailing list
>> Difx-users at listmgr.nrao.edu
>> https://listmgr.nrao.edu/mailman/listinfo/difx-users
>>
> _______________________________________________
> Difx-users mailing list
> Difx-users at listmgr.nrao.edu
> https://listmgr.nrao.edu/mailman/listinfo/difx-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listmgr.nrao.edu/pipermail/difx-users/attachments/20250122/5f6040ba/attachment.html>