A few requests for ephemeris visualization (AstroCalc)

[Atque]

Not urgent!

I wish for a few improvements of the ephemeris visualization in AstroCalc.

• Being able to change the symbol of the marking. E.g. a cross, a star, a ring, general comet symbol etc.
• Being able to show markings only when labled. This means that I can choose to show e.g. Hale-Bopp's position from 1997-01-01 to 1997-12-31, with 1 day intervals, but only show the markings at e.g. 10 day intervals. This means the line keeps smooth, but without markings in every breaking point. See this image for a suggestion:
  https://upload.wikimedia.org/wikipedia/commons/f/fc/Comet_Hale-Bopp_starmap_1997.png
• Being able to use more customizable labels. For example, I would like to show only day and month, or year and month, or just day and hour.
• Perhaps some antialiasing of the lines and symbols?

[axd1967]

this would be nice for comets; if I understand well, Stellarium already has a drawing model for those.

so one would see the orientation of a comet along the predicted positions.

(I think that is big enough to be dealt with in a separate issue.)

[gzotti]

Far from trivial. A general comet icon could be drawn rotated with a tail pointing away from the sun. But the appearance of the tail model cannot be queried.

[axd1967]

Far from trivial. A general comet icon could be drawn rotated with a tail pointing away from the sun. But the appearance of the tail model cannot be queried.

So the current representation of comets is also an approximate? Wouldn't that be a good starter?

[gzotti]

Alright. Looks like the next comet with obviously false MPC data. Please edit its elements and reduce absolute magnitude by ~20 or 23 magnitudes... Or did I miss something big? You also seem to have two entries for it. Delete one.

[Atque]

@axd1967 The comet symbol turning its tail in the opposite direction of the sun for every position would be really nice and probably help a lot in understanding comet orbital movements and maybe plan photos etc. I have no idea how much harder that would be to implement. I had in mind a simple symbol with constant tail direction.

[axd1967]

Alright. Looks like the next comet with obviously false MPC data. Please edit its elements and reduce absolute magnitude by ~20 or 23 magnitudes... Or did I miss something big? You also seem to have two entries for it. Delete one.

yes... I was long time wondering what went wrong, but it's not a big issue. Don't worry, I take it with a lot of salt ;-) in this case it's more to show the current Stellarium behaviour.

(A, B and C are three distinct comets from the MPC sources).

[alex-w]

@Atque I have question for 3rd item (Being able to use more customizable labels.): Is smart mode unacceptable for you?

[Atque]

@alex-w Smart mode is not unacceptable, but I think it could be too limiting.

[alex-w]

Please check version 0.20.3-4b8e7fd1c8: https://github.com/Stellarium/stellarium-data/releases/tag/weekly-snapshot

[alex-w]

@Atque I have a question for the 1st item: maybe just create markers according to the type of celestial body (a "smart marker")?

[Atque]

@alex-w Yes, that could be useful. But in that case, I would like to have two options: 1. Use "smart markers", and 2. Use normal markers (the circle marker used today).

What do you think about the comet marker with a tail always pointing away from the sun? How much more complicated would that be to implement, compared to a simple static comet symbol?

[axd1967]

What do you think about the comet marker with a tail always pointing away from the sun? How much more complicated would that be to implement, compared to a simple static comet symbol?

I find this interesting because the workaround is to use the angle measurement tool to get an idea of the sun angle.

the length could be configurable in pixels.