Stellarium - Incorrect Mag 7.55 star in Markarian's Chain?

[MercianDabbler]

This one has been throwing my star hopping off for several days. I could not find this star in the EP and assumed I must be doing something wrong. It finally occurred to me to look more carefully at some photos of the region and it seems that there is no mag 7.55 star in that position.

The web version of Stellarium doesn't show it so clearly 'the truth is out there'.

I've tried downloading the latest desktop version (0.21.0) but the star is still there.

Do other folks see the same thing and is there any way to get a corrected star catalog?

[John]

That's odd. On my version of Stellarium (0.21.0) the object in the position highlighted in your screen shot is NGC 4435, the 2nd of "The Eyes" galaxies. No star shown there

[MercianDabbler]

2 hours ago, John said:

That's odd. On my version of Stellarium (0.21.0) the object in the position highlighted in your screen shot is NGC 4435, the 2nd of "The Eyes" galaxies. No star shown there

 

Thanks for checking. Both 'eyes' galaxies are there on mine if I zoom in far enough, with 4435 right next to the spurious star.

Well odd.

I can only guess that there is something wrong in one of the data files but pinning it down seems like it would be a lot of effort.

I'll try a complete wipe and a fresh install and see if that makes it go away.

[MercianDabbler]

@John I looked at your screenshot again after posting my previous message. I think you may have the mag 7.55 star too but it is probably luck whether Stellarium shows the galaxy or the star description when you click there.

I have now disabled the magnitude limits in mine so that all of the galaxy labels appear. Here is a view with background images ON and stars OFF (Sky and Viewing Options Window). The second 'eye' shows as an oval symbol.

The same with stars ON - now the same galaxy has a white circular star splodge over it. To me the second 'eye' looks white and circular on your screen shot too.

[philtodd]

I recently downloaded Stellarium (0.21.0) and that mag 7.55 star is there, on top of the galaxy ...

[MercianDabbler]

2 hours ago, philtodd said:

I recently downloaded Stellarium (0.21.0) and that mag 7.55 star is there, on top of the galaxy ...

Thanks... kinda glad it's not just me.

I'm not sure if anything can be done about it. I believe that the star catalogues originate elsewhere (and from more than one place) but how to track down the source of this incorrect star and get it corrected is not clear to me. There is no identifier or name for the star that might give a clue.

[Corncrake]

On 16/04/2021 at 18:58, MercianDabbler said:

Do other folks see the same thing and

This is very odd indeed, yes, I see it in my Stellarium and I m still on 0.18.0 so it has been in the cats for a long time!

Cant be a very much observed bit of sky !lol!

Not much help, but it is in the stars_2_0v0_7.cat  (yours may not be _7 for a later install but it is the third of the base star cats.)

 

Edited April 22, 2021 by Corncrake

[MercianDabbler]

26 minutes ago, Corncrake said:

This is very odd indeed, yes, I see it in my Stellarium and I m still on 0.18.0 so it has been in the cats for a long time!

Cant be a very much observed bit of sky !lol!

Not much help, but it is in the stars_2_0v0_7.cat  (yours may not be _7 for a later install but it is the third of the base star cats.)

 

Cheers. I did discover that the catalog file format is documented on the old Sourceforge Wiki for Stellarium. Documented... but very far from straightforward so I don't think there is much of a chance that someone could easily open the thing up and correct it.

[Corncrake]

3 minutes ago, MercianDabbler said:

Cheers. I did discover that the catalog file format is documented on the old Sourceforge Wiki for Stellarium. Documented... but very far from straightforward so I don't think there is much of a chance that someone could easily open the thing up and correct it.

not at all easy ! I have had a look in with a hex editor, but nothing obvious yet.

Yes, saw that documentation, but not yet started counting the bits/fields/headers. Dont even know if that still applies to recent versions, some of those pages are well out of date, the most recent I can find attributing the source of the cats is that 0, 1, and 2 are from Hipparcos and 3 is Tycho, but that was in ver 0.14.1 !! Dont know where recent documentation is to be found the stellarium main page still points to that old wiki

But if it was from either of those it would/should have a name, and at mag7 many names even, so 'taint an error in those source catalogues ! lol  Maybe it is an easteregg or a copy telltale ?

[MercianDabbler]

2 hours ago, Corncrake said:

 Maybe it is an easteregg or a copy telltale ?

Pain in the posterior more like