Constellations and star's name related...

[ElChristou]

...I don't use any asterisms. I know the stars in and out since I built my first telescope at the age of 11 or so. Therefore that asterism subject really doesn't excite me too much anymore...

That I can imagine; in fact it don't excite me either, but indeed what makes me open this thread is that after the questioning of this friend of mine and principally of his 9 years old boy, I realize that people with heavy background like most users here tend to forget the younger users who actually are discovering the night sky through a screen because there is too much smog above their head to see something. For those kids, name are important just like asterisms because it's a beautiful way to learn how to read the stars...

[ElChristou]

Fridger, looking at those others asterisms.dat, I see what you mean about the use of weak stars, but actually even our file use some pretty weak stars (68 Ori, Xi2 Ori for example). So here what I think could be done: at mag 7 (auto mag ON), displaying the asterism in full screen (the biggest possible seeing all it's components), if some labels are present and make sense to increase a bit the expressiveness of the figure, then let's add them. It's the case of the above Canis Major asterism, all stars get their labels, so to me it's all good... Opinion?

[ElChristou]

Better name positioning, a few constellations with more commonly represented figures...

asterism.dat

[ElChristou]

Or we need some localized files adapting the asterisms depending on the user nationality! THAT would be original! (what soft will do such thing? )

What naive I'm!
What soft? Stelllarium!

Indeed it's a small team but really pretty good! After years I go for a look at their site (which is brand new and pretty well done) and what I see?

They propose Chinese, Korean, Polynesian, Inuit and even ancient Egyptian asterisms!

That's what I call a pretty good coverage! Bravo the Stellarium team!

Now ok, it's normal because after all they are specialized in night skies, but the effort is still nice...

[t00fri]

Their "baroque" hyper de luxe asterisms might be interesting for historians, but from an astronomer's point of view it's plain horrible. My opinion at least.

F.

[ElChristou]

Their "baroque" hyper de luxe asterisms might be interesting for historians, but from an astronomer's point of view it's plain horrible....

You mean the drawings?

[ElChristou]

Their "baroque" hyper de luxe asterisms might be interesting for historians, but from an astronomer's point of view it's plain horrible...

I've been quite surprised to read that nowadays asterisms and boundaries are not used anymore by professionals (the huge digital database are used via coordinates and so), only amateurs still use them and we can say that they are now part of the history or even the folklore of astronomy... True?

[chris]

The reason the name Capella is not displayed is because of Fridger's binary files, but this is really related to an underlying deficiency of the .stc file parser which has forced Fridger into a sub-optimal solution.

In spectbins.stc, Capella (=ALF Aur) is redefined:

Code: Select all

 Barycenter 24608 "ALF Aur"
 {
 RA        79.172065
 Dec       45.999031
 Distance  42.200414
 }


This wipes out the other associations to the star. If Fridger had defined the barycenter without the name part, the star names would get transferred with the HIP number. Alternatively what could be done is to use the full name definition from starnames.dat, however this would in effect force Fridger to track all changes to starnames.dat and update the binary star files if necessary, which is clearly not ideal.

Unfortunately what prevents this is the following bug, which I have brought up for quite a while now but is still present: catalogue references are not handled by the code that resolves the OrbitBarycenter property. This means that Fridger has to use ugly code like the following (from visualbins.stc) to get the binaries to work:

Code: Select all

 Barycenter 2237 "HIP 2237"
 {
 RA         7.088207
 Dec      -20.334776
 Distance 105.181230
 }

This associates the NAME "HIP 2237" with the star HIP 2237 (and also inserts it into the name list displayed after you press ENTER), which enables the barycenter to be referred to in the star definitions. This is clearly an ugly hack which is necessitated by the failure of OrbitBarycenter to resolve catalogue numbers.

You're right that OrbitBarycenter should resolve catalog numbers as well as names. I made a fix to do just this, but Capella still shows up as Alpha Aur A. The reason is that no label is shown for the invisible barycenter: instead, just the label of the visible component is shown. The same thing is happening with Sirius: the label is 'Sirius A', not 'Sirius'.

--Chris

[t00fri]

Their "baroque" hyper de luxe asterisms might be interesting for historians, but from an astronomer's point of view it's plain horrible...

I've been quite surprised to read that nowadays asterisms and boundaries are not used anymore by professionals (the huge digital database are used via coordinates and so), only amateurs still use them and we can say that they are now part of the history or even the folklore of astronomy... True?

To clarify a bit what I meant: An astronomer looking into the sky certainly recalls some correlation of stars by lines for orientation purposes. But these are rather abstract constructs or at least very simplistic geometrical figures. Certainly not big dogs (CMa) with big ears, four legs, a tail, a penis etc

What is a much more useful aid are virtual geometrical guides, like following an orthogonal line half way beween another line between star A and star B, for example. or the familiar star hopping method (see e.g. http://www.nightskyinfo.com/star-hopping/)

Bye Fridger

[ElChristou]

Ok... Finally, it's clear that this topic is really a matter of "education", each person will find what he learn and he used to... One good point of XEphem is the use of plain line for basic asterism and dotted one to achieve the complex figures. I find this a pretty cool solution...

[BobHegwood]

If it makes you feel any better there ElChristou...

I have never, never even seen the asterisms in Celestia.
um, a "matter of education?"

[ElChristou]

...I have never, never even seen the asterisms in Celestia...

I don't believe you!

[BobHegwood]

I don't believe you!

TRUTH...

I have never even had the slightest urge to view them. Still none.
I'm interested in seeing what is REAL, not what is imagined.

How about them apples?