Stellarium

lp:~stellarium/stellarium/fix-DeltaT

Created by gzotti and last modified

This branch should fix some mental twists currently performed around application of DeltaT.

This branch keeps JD in core as JD(UT) with its DeltaT attached in a QPair. Functions using a time argument must decide which flavour of JD is required (getJD() without DeltaT [everything converning time on Earth, calendars, sunrise, ...], getJDE() comes with it [planet and lunar positions]). A few function prototypes had to be changed to cater for mixed cases, those will now be called with separate JD and JDE parameters.

For the user not much changes. Time is still displayed in UT (or just with timezone offset) as expected. Only when changing DeltaT algorithm in the GUI, the displayed time does not change, and earth rotation (i.e. displayed time) does not jump by the difference in deltaT settings.

I have also added a small change that changes the tooltip text on the calendar panel as "Julian Calendar" if date < 1582-10-15.

I have tested with the JPL Horizon data given in https://bugs.launchpad.net/stellarium/+bug/1126981. a difference of about one arcsecond can be explained by slightly different values of deltaT and model of precession or not-yet-use of nutation.
I have also checked satellite times (ISS passage) against heavens-above. Crossing 10° altitude and going into shadow match to the second!

I think we can merge.

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bzr branch lp:~stellarium/stellarium/fix-DeltaT
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Owner:
Stellarium
Project:
Stellarium
Status:
Merged

Recent revisions

7755. By gzotti

most explanatory pre-review comments removed before merge. A few have to stay in, explain open questions for plugin authors!

7754. By gzotti

Moved the remaining plugins to the new, more coherent use of JD with or without DeltaT

7753. By gzotti

applied cleaner data flow concerning JD and JDE.

7752. By gzotti

changed var names' JD->JDE to indicate their real meaning: deltaT-patched JD

7751. By gzotti

A first few changes, mostly comments/docfixes or renamed functions, const'ed parameters etc.

7750. By gzotti

fixed compiler warnings on size_t

7749. By gzotti

Bumped copyright year

7748. By gzotti

Merged in gz_fix-ecliptic-obliquity. Finally we have good precession!

7747. By Alexander Wolf

fixed unit test compiling

7746. By gzotti

merged in branch gz_viewportOffset. Brings an option to lower the horizon, e.g. for a widescreen cylindrical view with mostly sky and ground on lower screen border.

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