bug: reason why some people cannot find VY Canis Majoris

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jsotola
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Joined: 19.08.2009
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bug: reason why some people cannot find VY Canis Majoris

Post #1by jsotola » 19.08.2009, 04:21

if you type in "HIP 35793" nothing is found

for some reason the star database has two spaces between HIP and 35793 (windows version anyway)

if you type two spaces then the star will show up

it is the same for HD 58061 !!! two spaces

it shows up correctly with "SAO 173591"

maybe others are the same way

js:)

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t00fri
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Re: bug: reason why some people cannot find VY Canis Majoris

Post #2by t00fri » 19.08.2009, 08:56

jsotola wrote:if you type in "HIP 35793" nothing is found

for some reason the star database has two spaces between HIP and 35793 (windows version anyway)

if you type two spaces then the star will show up

it is the same for HD 58061 !!! two spaces

it shows up correctly with "SAO 173591"

maybe others are the same way

js:)


1) when reporting a suspected bug, please always specify which Celestia version you are referring to!

2) I could not confirm anything of what you wrote, neither in version 1.6.0 nor in the current SVN version, since that star HIP 35793 is NOT part of the Celestia data base (anymore?).

3) As you can easily check in the original HIPPARCOS catalogue (ESA 1997),
http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/239

the uncertainty in the parallax of HIP 35793 is twice its value (1.78 +- 3.54 mas), hence a sensible distance cannot be derived! That's why this star has been eliminated from Celestia's data base.

Fridger
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ajtribick
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Re: bug: reason why some people cannot find VY Canis Majoris

Post #3by ajtribick » 19.08.2009, 18:59

For some reason the star was included in the pre-1.6.0 database. Since the documentation for that version of the star database was rather obscure, I'm not entirely sure why this was.

Fridger has given the parallax in the old reduction of the Hipparcos data. The new reduction can also be easily found online, and it is this reduction that the v1.6.0 star database is built from. The entry for VY CMa is at http://vizier.u-strasbg.fr/cgi-bin/Vizi ... ecno=35688

As you can see, the parallax is given as -4.35±4.99 mas. Negative parallaxes are unphysical, and thus all such stars were eliminated from the database.

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t00fri
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Re: bug: reason why some people cannot find VY Canis Majoris

Post #4by t00fri » 19.08.2009, 20:51

ajtribick wrote:For some reason the star was included in the pre-1.6.0 database. Since the documentation for that version of the star database was rather obscure, I'm not entirely sure why this was.

Fridger has given the parallax in the old reduction of the Hipparcos data. The new reduction can also be easily found online, and it is this reduction that the v1.6.0 star database is built from. The entry for VY CMa is at http://vizier.u-strasbg.fr/cgi-bin/Vizi ... ecno=35688

As you can see, the parallax is given as -4.35±4.99 mas. Negative parallaxes are unphysical, and thus all such stars were eliminated from the database.

Yeah, of course I also have checked the values in the new reevaluation, but skipped the references because they gave no essential change within errors and because of mere lazyness (only back from hiking in "paradise" since today ;-) ).

Fridger
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Topic author
jsotola
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Re: bug: reason why some people cannot find VY Canis Majoris

Post #5by jsotola » 23.08.2009, 18:59

my bad

i have celestia on two computers and have version 1.5.1 (winxp) on one where the bug show up

it did the day that wrote the post anyway
today it shows using any number of spaces

i quadruple checked before posting just to be sure of what i was seeing

i may have used a cel script that somehow caused the problem

the other computer has version 1.6.0 (winxp) and the star is not in the database as previously stated that it has been removed

please consider my original post to be a bogus post

thanks

Danny Lorraine

Post #6by Danny Lorraine » 22.05.2018, 06:24

celestia should definitely include VY Canis Majoris in the next update


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