First, I just want to echo what others have said about the Astrolabe pages being really nice. I'm super glad the crafting compendium gets a link!
The but is that it seems like the calendar's in-game time conversion is doing something weird with the last 3 days of the month. I'm particularly bringing it up because the update announcing the Astrolabe site said it should be working.
A month gets to the 27th then leaps to the "0th" before incrementing normally again. I checked a couple other months and the same was happening there. As Faerun has 30 day months, I assume something's off here - and not all the month's I checked have the weird in-between days either (which I thought might be what day 0 is supposed to represent).
In fact, at time of writing, it says we're at 2:30am on Day 0 Uktar. I hopped in game to make sure this wasn't oddness with the in-game date, but we're on day 28 Marpenoth, as it should be.