Hubble constant narrowed down to 74.2

74.2 ± 3.6 km/s/Mparsec, that is.

Yousuf Khan

The Universe is expanding at 74.2 km/sec/Mpc | Bad Astronomy | Discover
Magazine
"The cool thing is, NGC 3021 and others like it have Cepheids in them,
and are also known to have hosted Type 1 supernovae! Over ten years ago,
a Type I went off in NGC 3021, and very precise measurements of it were
made, including how far away it was. So for galaxies like NGC 3021 we
have two methods of measuring distances which can be tied together in a
single galaxy that can be observed with a single telescope, like Hubble.
That means that uncertainties in the distance measurements using the two
systems can be hammered away, and we get more reliable measurements."
http://blogs.discovermagazine.com/ba...-742-kmsecmpc/