Celestia Forums

Hi

Can anyone point me to where I can download the Tycho 1997 catalogue already in Excel format?
Looking for all stars up to around 40 light years away.

Thanks

John,

The ESA Tycho catalog does not include any distances or parallax values.

There have been catalogs generated from it which include estimated distances derived from stars' spectrographic information. Two such are available on the CelestiaMotherLode: a 1-million star database and a less accurate 2-million star database. You can use Celestia's star browser to select the stars within 40LY. You could write a CelX (Lua) script to get more detailed information.

I don't know of any Excel spreadsheets created from that information, and a quick Web search didn't turn up any, either.

johnpickin wrote:Hi

Can anyone point me to where I can download the Tycho 1997 catalogue already in Excel format?
Looking for all stars up to around 40 light years away.

Thanks

Why don't you let us know a bit more about what you want to do?

Off hand it doesn't look like a very sensible idea to involve EXCEL here. The standard star catalogs are available in various formats (ASCII, HTML etc) at the global astronomical servers, such that one can easily access ALL the information online. There are many (cross-platform) scripting languages (Perl, LUA,...) that allow easily to select and read out (in Celestia compatible format) particular entries of these large data tables.

Fridger

johnpickin wrote:Hi

Can anyone point me to where I can download the Tycho 1997 catalogue already in Excel format?
Looking for all stars up to around 40 light years away.

Thanks

Actually, I have all stars with measured parallaxes from the Hipparcos mission out to 60 LY or so. (with a scattering of them afterward). Excel format, several columns -> Name, distance, spectral, RA, Dec, Parallax, Mass, temperature, log g, [Fe/H], etc etc.

PM me your e-mail address and I'll e-mail it to you.

Hungry4info wrote:

johnpickin wrote:Hi

Can anyone point me to where I can download the Tycho 1997 catalogue already in Excel format?
Looking for all stars up to around 40 light years away.

Thanks

Actually, I have all stars with measured parallaxes from the Hipparcos mission out to 60 LY or so. (with a scattering of them afterward). Excel format, several columns -> Name, distance, spectral, RA, Dec, Parallax, Mass, temperature, log g, [Fe/H], etc etc.

PM me your e-mail address and I'll e-mail it to you.

Hungry,

I'd be very curious to learn why you did not use the VERY convenient HTML interface (VisieR) from CDS Strasbourg instead of EXCEL?

http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/196

I simply can't see any justification for EXCEL in this context ....

Analogously for Tycho, of course,
http://vizier.u-strasbg.fr/viz-bin/Vizi ... rce=I/197A

except that there are no parallaxes in the original catalog, only a flag that indicates whether the parallax is known or not.

If the parallax is also desired in the context of the Tycho catalog, then one needs to use the HTML interface of The Hipparcos and Tycho Catalogues (ESA 1997)

http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/239

Fridger

PS: Note that there is a more recent and much more accurate reevaluation of the HIP parallaxes on which the new Celestia star.dat is based. So it's not a good idea to use star distances from older sources!

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Floor van Leeuwen, 2007 Hipparcos, the New Reduction of the Raw Data
Astrophysics & Space Science Library #350.
available at http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/311

or again via the most convenient HTML interface (VisieR)

http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/311
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

t00fri wrote:I'd be very curious to learn why you did not use the VERY convenient HTML interface (VisieR) from CDS Strasbourg instead of EXCEL?

I started the excel document several years ago. I'm not familiar with how to use VisieR but I'll go check it out. Thanks for the advice!

Hungry4info wrote:

t00fri wrote:I'd be very curious to learn why you did not use the VERY convenient HTML interface (VisieR) from CDS Strasbourg instead of EXCEL?

I started the excel document several years ago. I'm not familiar with how to use VisieR but I'll go check it out. Thanks for the advice!

OK thanks. That's what I figured...

The nice aspect of all VizieR HTML interfaces@ CDS Strasbourg is that you may trivially select those data columns from the full table that are of interest to you. Moreover, there are different formats available for downloading the entire customized data set (HTML, ASCII with different separators etc)

...last not least you may be sure of getting always the current version of the official catalog in question...

Fridger

Dear Seddon

Thanks for your response.
<<The ESA Tycho catalog does not include any distances or parallax values.>>
I thought it did though. Most sources seem to imply it does - can you explain what's happened there then.
See: http://apm5.ast.cam.ac.uk/hipp/tycho.html
or http://adc.gsfc.nasa.gov/adc-cgi/cat.pl ... gs/1/1239/

The reason I was looking for an Excel version is simply that I am familiar with Excel and not VisieR or Lua.
I can see the stars manually in Star Browser - but can't see an obvious way to extract them at the moment.

johnpickin wrote:Dear Seddon

Thanks for your response.
<<The ESA Tycho catalog does not include any distances or parallax values.>>
I thought it did though. Most sources seem to imply it does - can you explain what's happened there then.
See: http://apm5.ast.cam.ac.uk/hipp/tycho.html
or http://adc.gsfc.nasa.gov/adc-cgi/cat.pl ... gs/1/1239/

The output from these interfaces is from the catalog I was referring to (if you had read my post carefully). The official reference of the catalog underlying these URLs is

The Hipparcos and Tycho Catalogues (ESA 1997), I/239
Here the parallaxes are from the Hipparcos data.

Selden was referring to the original Tycho catalog that I also mentioned in my post:

Tycho Input Catalogue, Revised version (Egret+ 1992) I/197A or even an earlier version.
There are no (independently) measured Tycho parallaxes as Selden correctly emphasized.

The reason I was looking for an Excel version is simply that I am familiar with Excel and not VisieR or Lua.
I can see the stars manually in Star Browser - but can't see an obvious way to extract them at the moment.

You don't need any skills for customizing, reading out or downloading the star data in the VizieR WEB interface! That's the whole point.

Fridger

Parallax values are available for only a very small fraction of the stars.

The 2,539,913 star Tycho-2 catalog includes the 118,218 stars of the Hipparcos catalog of stars which had their parallax values measured. The Tycho catalog itself does not include the Hipparcos parallax values, although it does include the Hipparcos catalog number for the appropriate stars. This makes it possible for people to merge the two catalogs and provide a database which includes the parallax values from the Hipparcos catalog.

http://tdc-www.harvard.edu/catalogs/tycho2.format.html is one of the sites which describes the Tycho-2 catalog in detail.

Detailed information about the Tycho and Hipparcos catalogs is available at
http://www.rssd.esa.int/index.php?project=HIPPARCOS

Took me 30 seconds to realise that this VisieR is pretty darned convenient

Hungry4info wrote:Took me 30 seconds to realise that this VisieR is pretty darned convenient

Yeah, I really think so, too.
Fridger

selden wrote:Parallax values are available for only a very small fraction of the stars.

The 2,539,913 star Tycho-2 catalog includes the 118,218 stars of the Hipparcos catalog of stars which had their parallax values measured. The Tycho catalog itself does not include the Hipparcos parallax values, although it does include the Hipparcos catalog number for the appropriate stars. This makes it possible for people to merge the two catalogs and provide a database which includes the parallax values from the Hipparcos catalog.

http://tdc-www.harvard.edu/catalogs/tycho2.format.html is one of the sites which describes the Tycho-2 catalog in detail.

Detailed information about the Tycho and Hipparcos catalogs is available at
http://www.rssd.esa.int/index.php?project=HIPPARCOS

Selden,

I have to disagree somewhat. There is not just one Tycho catalog (the original one I/197), but several ones, meanwhile. As I discussed above repeatedly, there is also an official ESA 1997 catalog that has the Hipparcos parallax values merged with Tycho stars.....(I/239)

Just have a closer look to my above description of the various catalogs related to Tycho and HIP. The catalog descriptions you were referring to above are part of the official catalogs and hence are also available in the global astronomical database at the CDS Strasbourg server.

Fridger

Back when I was revamping the star database, I did come across this issue with the Tycho catalogue.

The version of Tycho released in 1997 (call it Tycho-1 for now) does have parallaxes included, and these are not the same as the parallaxes in the version of Hipparcos released at the same time (which I'll call HIP1 to distinguish it from the van Leeuwen reduction HIP2) - they usually have far larger errors, and there are some stars which aren't in Hipparcos which nevertheless do have Tycho-1 parallaxes.

e.g. Regulus = Alpha Leonis = HIP 49669 = TYC 833-1381-1

HIP1 parallax: 42.09 ± 0.79 mas (link)
Tycho-1 parallax: 42.40 ± 2.20 mas (link)

Tycho-1 parallaxes are NOT the same as HIP1 parallaxes.

The Tycho-2 catalogue includes more stars and does not have parallax measurements associated with them.

ajtribick wrote:
e.g. Regulus = Alpha Leonis = HIP 49669 = TYC 833-1381-1

HIP1 parallax: 42.09 ± 0.79 mas (link)
Tycho-1 parallax: 42.40 ± 2.20 mas (link)

Tycho-1 parallaxes are NOT the same as HIP1 parallaxes.

Andrew,

I suppose we agree that there was never an independent parallax measurement within the Tycho project. As you can see, the values of the above HIP1 parallax and the Tycho-1 parallax are only formally different, yet physically, they are the same (within errors!). This naturally happens if --in the course of time-- there were somewhat different analyses of the HIP raw parallaxes, along with Tycho data, just like the most recent one by Floor van Leeuwen (2007). This then led to slightly different center values with significantly reduced errors. No mystery whatsoever in my view...

Fridger