UCAC4 Catalog

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proulxf012
Posts: 3
Joined: 03 Jan 2018, 20:05

UCAC4 Catalog

Post by proulxf012 » 17 May 2018, 00:02

Hi. I am downloading the UCAC4 catalog (this is loonnngggg...). I am wondering what to do with it afterward. Since I am using the linux version, i just dumped the other 2 catalogs (G16, G17) in /opt/hnsky. Will it be the same with this one? Including the index?

Thanks again for some great work

François Proulx, Longueuil, Québec, Canada
François Proulx, Longueuil, Québec, Canada

han.k
Posts: 68
Joined: 23 Nov 2017, 15:04
Location: The Netherlands
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Re: UCAC4 Catalog

Post by han.k » 17 May 2018, 00:28

Hello François,

The number of stars in the G17 is about the same as in the UCAC4. The G17 and G16 are based on the very latest and accurate Gaia catalogue and have the advantage they allow 180 degrees field-of-view but also small fields. The stars have however no number/destination except for an artificial based on the ra&dec position.

The UCAC4 allows only small field-of-view but has three minor advantages

1) The stars have a label. (hardly any advantage)
2) Star proper motion is included.
3) Most stars have some color data. See status bar.

The most important advantage is proper motion. If you want to simulate star movement over decennia or centuries, you can do that in simulation mode with the UCAC4.
See https://www.youtube.com/watch?v=uDH_mR7oWZk

I would just keep it you have space but use primary the G17 for imaging and the G16 for visual work

Place the UCAC4 somewhere on you home folder and link HNSKY to it.

Han

proulxf012
Posts: 3
Joined: 03 Jan 2018, 20:05

Re: UCAC4 Catalog

Post by proulxf012 » 17 May 2018, 01:21

Hi Hans
Thanks. OK. I can probably do that. Now, is it important that all files are in order: z001 to z900? For some reason, I forgot some file and downloaded them out of order. They are shown out of order in my Downloads folder. Also, the index file, it is important where it is in the future UCAC4 folder?

Regards

François Proulx, Longueuil, Québec, Canada
François Proulx, Longueuil, Québec, Canada

han.k
Posts: 68
Joined: 23 Nov 2017, 15:04
Location: The Netherlands
Contact:

Re: UCAC4 Catalog

Post by han.k » 17 May 2018, 15:58

Yes file z001 to z900. Furthermore you need the index file, u4index.unf.

Where the files are located is not important. Suggest to place them in a directory under home.

De catalogue kicks in if you zoom in. You could test without having all the z.. files. The Z001 is for the celestial south and Z900 the north. (or the other way around)

Han

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