AstroCalc puzzler

[matt]

Among my numerous sw apps for predicting planetary positions/views, I have AstroCalc.

Up until now I've found it to be excellent, especially for predicting GRS transits.

But I just encountered something really strange. I moved ahead to early tomorrow morning but instead of ticking over to May 1... it read April 31.

What the??? Has the IAU added an extra day in April or have I found a flaw in this otherwise nifty and reliable little proggie???

And what does this mean going forward? Will the program now be perpetually out by a day?

[matt]

Not to worry.

I think I've got it sorted

[[1ponders] (Paul)]

Seeing as you have sorted your own problem out, how about having a go at mine. I've stopped using Astrocalc as it never shows me the correct times for rise. transits and sets. It doesn't matter if I have it set in UT or local. They are usually 10-20 min out, but Jupiter is 4 hrs + out.

These times are comparisons between astrocalc and Astronomy 2006, Starry Night 5 pro and Occult V3. All are late times by astrocalc.
eg.
Today
Mercury 9 min out in setting
Mars 11 min out in setting
4 hours 17 min late
Saturn doesn't give a set time. It seems to think Saturn will set tomorrow thought the rise times differ by 14 min



Any ideas?