I placed in the files section of the group, the Goffin Planetary chart
which gives general information and locator charts. Steve Preston
maintains the IOTA Asteroid occultations, and his website is located
at: http://www.asteroidoccultation.com/
Since astrometry closer to the event can actually shift the path, the
article in S&T gives general information, but that can change.

Incidently there is a NEW version of the Tycho2 catalog for Occult.

Denis V. Denissenko wrote:
"The cause of problem was identified - wrong order of stars in several
regions in Tycho2.dat. To make long story short, stars *were* there,
but WinOccult was *not* finding them because they were not at their
places.

I have completely rearranged Tycho2.dat in the correct order and also
recompiled tycho2.inx file. There are still all the same 3375961 stars,
but now WinOccult is finding by 3-3.5 per cent more occultations!
Especially in Gemini, Auriga and Taurus between declinations of
+23.5..+24, +24.5..+25. +26.5..+27, +29.5..+30 and in Capricornus and
Aquarius at -2..-2.5 and -5..-5.5 bands. These are the results of my
test with occultations of stars brighter than 10.5m in 2005.

The fixed version of Tycho2.dat and tycho2.inx is uploaded at
http://hea.iki.rssi.ru/~denis/TychoNew.zip (64.264.832 Bytes, or 62758
kB). Perhaps it will be desirable to upload the replacement at IOTA ftp
site after additional testing by Dave Herald and one or two
calculators. If you have some downloading software like Download Master
or something like that, please use it rather than simple "Save as" from
your browser. File is too large, so it might take several attempts."

David Herald (author of Occult) wrote:

I'm very happy to advise that I have now done a series of checks on the
files that Denis has re-created, and they are fine.

Denis - thanks for the great work in fixing up this bug.

Rob - can you upload the files from Denis' site, and put them on the IOTA
site with some explanatory notes. Main guidance - the new files
required are
Tycho2.dat, Tycho2.inx, and HipparcosIndex.dat - and these simply replace
the existing files of that name in the StarCats directory.

Dave H

The file is also located at the IOTA FTP site:
ftp://lunar-occultations.com/pub/

More detailed information can be found on the Occult Yahoo discussion
group archive located at:
http://groups.yahoo.com/group/occult-software/


Rob Robinson
VP of IOTA Occultation Services

--- In guide-user@yahoogroups.com, "toadatrix" <jsnyder@w...> wrote:
> I discovered that for some reason, I don't know why, the Tycho 2
> star 5244-0017 is not in the Tycho 2 catalog supplied with Occult.
> It is in Guide8 so I used the Guide8 position of it and added it to
> Occult. I then recomputed the occultation using Occult and the
> reported times and occultation path are similar to, but not exactly
> the same as, those shown by Guide8. Both Guide8 and Occult show
> paths for this event that are well to the north and west of the path
> shown in the March, 2004 Sky & Telescope.
>
> --- In guide-user@yahoogroups.com, "toadatrix" <jsnyder@w...> wrote:
> > According to the March, 2004 issue of Sky & Telescope (page 103,
> > 106) the asteroid 107 Camilla will occultate the 11.8 magnitude
> star
> > TYC 5244 0017 on Sept. 5, 2004 at around 9h UT. The map shown on
> > page 103 shows the central path passing over the southern part of
> > Wisconsin where I live. I calculated the same event in Guide 8b
> and
> > found the central path missing southern Wisconsin all together and
> > passing, instead, over the north west corner of Wisconsin.
> >
> > Since Guide has always been dead on accurate for me I have to ask
> > what accounts for the difference and which prediction (if any) may
> > be correct? I should mention that I also tried to find this event
> > with the latest version of Occult and I couldn't find it at all
> > (that was really surprising). Is there a way to get the latest
> > information into Guide so as to get the most accurate
> predictions?
> > Where would I go on the web to get that latest information?
> Thanks.