Conflicting Astronomical Data

[Andrew*]

I've come across this quite a bit recently, that different sources give significantly differing information particularly on the distance and magnitude of objects.

e.g. NGC 2149.

- According to Wikipedia, 300,000 ly from galactic centre and mag. 9.1

- According to Burnhams, 150,000 ly from GC and mag. 10.9

- According to seds, Calsky and Starry Night, ~295,000 ly from GC and mag. 10.4

It's even more variable with stars, I've noticed.

Calsky gives even the constellations wrong, saying NGC 2149 (Lynx) is in Leo and NGC 2655 (Camelopardalis) is in Draco.

So why the inconsistency, and more importantly, where does one find the most reliable data?

Andrew

[Stephen]

Step 1 - Don't trust Wikipedia

As to proper accurate data, I'm afraid I don't know - wikipedia can be altered by anyone though and someone's got to of got bored at some point and gone and edited the data .....

[kniclander]

I don't think we have any "accurate" data - isn't it all built up on pretty imprecise estimates, parallax effects, redshifts and variables and suchlike? There's quite a good book ("Measuring the universe") which sets out the history of it all.

[Glen]

i agree, Wikipedia is just the consolidation of the peoples opinions who add to it,

and those opinions very from fact to pure delusion, thats the way i look at it.

As for data i'd say the sky app is one of the more reliable.

Regards

Glen

[Hypernova]

Wiki isn't all bad, but it isn't the best either. There are a fair few dedicated contributors who properly source information from reputable websites and put up what extra information is required without changing it in any way to mislead people, they often reference the sites used so you can follow them and check the accuracy of the information yourself.

There does seem to be a lot of disagreements between different website on matters of distance and magnitude .etc, most probably down to just being copied from one web page to another and not verified in any way. The most likely place to find reasonably accurate data for any object is straight from the catalogues themselves, the data in these changes over time as measurements become more accurate and that might be another source of conflicting data.

[Demonperformer]

I use Catalogues and files available at CDS if I want to check latest thinking