How to elegantly convert datetime from decimal to “%d.%m.%y %H:%M:%S”?

Question

I am doing an experiment which produces automatically logged data. The software produces a timestamp that is of the format 41149.014850. I would like to convert

Answer 1

This gets close: The numbers indicate the number of seconds since a date close to 1/1/1900:

as.POSIXct(x*3600*24, origin=as.Date("1900-01-01")-2, tz="UTC")
[1] "2012-08-28 01:06:40 BST" "2012-08-28 01:14:01 BST" "2012-08-28 01:21:23 BST"
[4] "2012-08-28 01:28:44 BST"

There still is a timezone offset in there.