The only time I could come that close (still not to the very altar) was at 9:30 PM and it was very dark inside the cathedral. Other visits I made during day time I found the nave and aisels closed for public and people could only look inside through the bars :(

The Wiener Neustädter Altar, ordered in 1447 by Emperor Freerick III, is composed of two triptychs, the upper being four times taller than the lower one. When the lower panels are opened, the Gothic grate of the former reliquary depot above the altar is revealed. On weekdays, the four panels are closed and display a drab painted scene involving 72 saints. On Sundays, the panels are opened showing gilded wooden figures depicting events in the life of the Virgin Mary.