sat plugin: umbra at "distance" (should be "altitude") does not correspond to selected sat's umbra

[axd1967]

Expected Behaviour

Actual Behaviour

Additionally

• wordings
• phrasing: "show umbra at distance" should be "show umbra at altitude" (as noted in Earth shadow at sat altitude issues #2510 (comment))
• phrasing: "show Earth's umbra" should be "show umbra" or "show umbra for selected sat" (idem penumbra) because there is only one "Earth umbra", but each sat has its umbra (depending on altitude)
• what is meant by "C.U."? -> make it "CU" or "Centre of Umbra"

Steps to reproduce

System

• Stellarium version: 23.0.72-bdee5b6 [master]

Logfile

If possible, attach the logfile log.txt from your user data directory. Look into the Guide for its location.

[gzotti]

This "umbra at fixed distance/altitude" thingy currently seems anyhow not to do the things users would expect, at least not for LEO. We should disable the button and option at least for now. @alex-w ?
C.U. is Center of Umbra, like for Earth's shadow for the Moon.

[alex-w]

This "umbra at fixed distance/altitude" thingy currently seems anyhow not to do the things users would expect, at least not for LEO. We should disable the button and option at least for now. @alex-w ?
C.U. is Center of Umbra, like for Earth's shadow for the Moon.

Ok

[gzotti]

Back to the drawing board...

[github-actions]

Hello @axd1967!

Thank you for suggesting this feature.

[axd1967]

This issue is still open, nevertheless I'd like to add a snippet of observations:

The current ISS marathon is a nice example of what's happening:

The ISS orbit is in a momentary blackout (yellow segment, starts in Leo, ends below CrB), but the Earth shadow (drawn red) does not match what Stellarium predicts.

(colors inverted: yellow=visible, red=invisible, time in UTC)

Interestingly, Heavens Above does not predict the temporary passage in darkness:

(times in HA screenshot are UTC+2)
(https://heavens-above.com/passdetails.aspx?&satid=25544&mjd=60078.0378598858&type=A)

http://www.satflare.com/track.asp?q=25544#TOP does:

tracksat.space:

[github-actions]

Hello @axd1967!

Please check the fresh version (development snapshot) of Stellarium:
https://github.com/Stellarium/stellarium-data/releases/tag/weekly-snapshot

[github-actions]

Hello @axd1967!

Please check the latest stable version of Stellarium:
https://github.com/Stellarium/stellarium/releases/latest

[axd1967]

looking good.
it should be "umbra" rather than "Earth umbra", because it is dependent on the selected satellite or altitude.

I see no reason to make the selected versus virtual sat altitude settings mutually exclusive: two are related to the selected sat, the third is related to the selected altitude value.

(Ideally, radio boxes should be employed to convey this desire.)

thx