Progress has continued fast in the last few weeks. The two new features which will be most visible are luminance adaptation and dynamic object labeling.

Luminance Adaptation

This feature is part of an overhaul of the calculation of brightness of objects. When enabled it dims all objects when a very bright object is visible. Thus, when the full moon is visible, dim stars will drop out of view.

This should not be confused with scattering of light in the atmosphere when a bright object like the full moon is in the sky, or because of light pollution - that effect brightens the sky, overwhelming the brightness of dim objects, and is only in effect when atmosphere is turned on. By contrast, luminance adaptation is effective even with atmosphere turned off.

To see what it is doing, set the field of view to about 30 degrees, and set the time so that it is a moonlit night. Then drag the sky about, letting the moon move in and out of view (off the side of the screen).

Visually, the effect reminds me of a video camera it is in dark conditions and then a bright light is suddenly brought into the field of view - the camera takes a little time to adjust the aperture and other settings so as to avoid saturation of the detector.

I suspect this will unnerve some people and is almost certainly not to everyone's tastes. If you don't like it, you can turn it off from the tools tab of the configuration dialog (the key to toggle configuration dialog is F2).

Dynamic Labeling

The behavior of labels has been changed. It used to be that the amount of labels was determined by the magnitude of the object which they mark. One problem with this was that when the "minimum magnitude to label" setting was such that quite dim objects were labeled, the display would become extremely cluttered at wide zoom levels.

To counter this problem, label visibility is now determined by a combination of an object's magnitude and the current zoom level. When the zoom is wide, the limiting magnitude for labels is adjusted so that fewer objects get a label. As the zoom level is increased, the limiting magnitude for labels is adjusted to include dimmer objects.

It is possible to adjust the amount of labels independently for stars, nebulae and planets from the markings tab of the view dialog (the key to toggle view dialog is F4).

Other changes include some speed improvements and a few minor style changes to the GUI. There is also a little more information in the sky culture descriptions, with some nice information about two of the Tupi constellations. The recent win32 build problems have been solved.

A test build for the win32 platform can be downloaded here.