Talk:Ananke group

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[edit] Source of data; group definition

The definition of the group (including which satellite is in which is out) depends on the model chosen, its parameters (e.g. velocity impulse) and the mean orbital data. Sheppard used Jacobson’s data (JPL site) known at the time. The orbits of the moons discovered in 2003 were not known with adequate precision, so Sheppard 2003(see refs in the article) did not use them. Nesforny used its own integration results but could not include 2003 moons either. These publications concur on 6 members only. I could not find other publication extending the list since, so listing fringe members cannot be referenced. I believe we should list only the satellites listed in the published sources even if the parameters of other satellites clearly fit into the group. Consequently, I removed the unreferenced list with (fringe members) S/2006 Jxx, providing instead a graph showing them. Please complete the list of core objects with published refs if I missed them.

Please note that the popular Sheppard’s page quotes Jacobson’s data for the orbital elements by the it does not appear to be kept up to date. The graphs use the most recent (Aug 2006) published Jacobson’s data. Finally, as mean orbital elems differ from one source to another, I suggest to use the size (i.e. magnitude) to order the (partial) list. Eurocommuter 11:32, 29 August 2006 (UTC)

I agree we should add only satellites that are listed as members in published papers/preprints. A comment on the diagrams you've created: I wonder if inverting colors (i.e. black lines on a white background) make them clearer? Aesthetically large black images don't fit the white background of the article. Otherwise I find them interesting and informative.--JyriL ^talk 10:15, 30 August 2006 (UTC)

Thanks. I agree that the choice of colours and readability of labels is an issue. I’m collecting remarks from different editors on all my diagrams and intend to implement some of them. To start with, the SVG->PNG transformer used by Wikipedia does a very poor job (lines are thick, fonts too thick becoming difficult to read,…). Moving to native PNG is probably inevitable. The choice of colours followed some initial logic (different colours for Jupiter, Saturn,…) but an alternative one would be preferable for the groups. The point of traditional black background for orbits is also difficult to defend. I’m collecting feedback and intend to put some alternative presentations resulting from it on my test pages. The good news is that once I feel some consensus, all graphs can be regenerated easily applying the same skin. Eurocommuter 11:45, 30 August 2006 (UTC)

To illustrate your point and see how it would look like I’ve inserted the negative version of two graphs used in Carme group article. We’ll se what other people think. Eurocommuter 16:12, 30 August 2006 (UTC)

Definite improvement, now the images looks much clearer! The lack of proper SVG support is really frustrating (am I correct that IE doesn't recognize that format at all? Even Firefox can't render them always correctly.) I've been pondering if I should create some diagrams and graphics myself using SVG. Must take these limitations into account...--JyriL ^talk 17:02, 30 August 2006 (UTC)

IE requires a plugin (e.g. from Adobe). The limitations of the transformer used by Wikipedia are crippling (e.g. no graphic maps possible as links are not implemented; no colour gradient for areas defined by arbitrary paths,...; all of these are properly implemented by Firefox / Adobe plugin..). The most annoying is when people who are unaware of the difficulties, in good faith, insert convert to svg tags on my (very few) png images on commons following official Wikipedia policy, advertising the benefits of SVG…that cannot be exploited. I believe I should join the discussions on meta on this policy and svg tooling. Eurocommuter 18:03, 30 August 2006 (UTC)

The advantages of the SVG format are so great that I think we should stick with it and not use PNG whenever possible. But if the conversion tool is as crippled as you said, obviously PNG is the only solution for images that can't be shown correctly until the tool is updated.--JyriL ^talk 18:21, 30 August 2006 (UTC)

For the record, I think the white backgrounds look better. The Singing Badger 19:09, 20 September 2006 (UTC)

Very well; waiting for a third vote and will re-plot them in a whiter shade of pale. Eurocommuter 20:45, 22 September 2006 (UTC)