Comment 21 for bug 1124221

Hello Alexander,

Are you able to help me to answer the below?

On 23 February 2013 13:09, Victor Reijs <email address hidden> wrote:

> On 23 February 2013 12:30, Alexander Wolf <email address hidden>wrote:
>
>> Code for change epoch for preparation of star catalog is here:
>>
>> http://bazaar.launchpad.net/~stellarium/stellarium/trunk/view/head:/util/ParseHip.C#L122
>>
>
> So it is important to know that the value is of deltayears in line 122?
> Is my assumption correct that deltayears = 'epoch of Stellarium' - 'epoch
> of the stars' ?
> 'Epoch of Stellarium'=J2000.0? IS this the correct reference epoch of
> Stellarium?
> 'epoch of stars' = J1991.25 (if using the original Hipparcos and *not* an
> already converted Hipparcos)
>
> Original Hipparcos cat (J1991.25) is at:
> http://www.rssd.esa.int/index.php?project=HIPPARCOS&page=hipsearch (using
> ID=32349)
> A converted Hipparcos catelogue (J2000.0) is at:
> http://simbad.u-strasbg.fr/simbad/sim-id?Ident=sirius&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id
>

I see in the zip file of the source there is a SimbadSearcher.cpp, which at
the end has a line:
    url += QString("set epoch J2000\nset limit %1\n query id
").arg(maxNbResult);
<to be honest I don't fully understang this and I don't know if this source
is reading the cat data into Stellarium>

For the Simbad catelogue J2000.0 is indeed true. But what value of Sirius
for instance is in the raw file that is being read in Stellarium?

All the best,

Victor