Yeah true, but I think they actually use wavelength of red shift, which is distance… traveled by light in the time it takes to make a full cycle. So I guess we’re back to seconds again.

I think they use this for distance and time because at scales being dealt with they have the same implications.

I think you need to be more specific than ‘long distance’, yes they use parsecs for ‘long distances’ but I believe only for intra-galactic objects. I think other galaxies are too distant for parallax seconds to be useful.

Don’t they measure distance and time by redshift (ie colour)