<p>Red shift is usually measured for galaxies rather than individual stars. Unless a star has just gone supernova, it's usually not bright enough to be seen even w the world's most powerful telescopes at the distances where cosmological redshift comes into play. <a href="http://en.wikipedia.org/wiki/Hubble%27s_law" rel="nofollow">Hubble's law</a> operates over <strong>large</strong> distances; the expansion constant being 67.8 km/sec per megaparsec (3.3 million light years) 
<a href="http://en.wikipedia.org/wiki/Andromeda_Galaxy" rel="nofollow">Andomeda galaxy (M31)</a> is 2.54 million light years away, and although some individual stars are visible at that distance, the galaxy has a net <strong>blueshift</strong> of 0.001001 (303 km/sec) due to its <a href="http://en.wikipedia.org/wiki/Peculiar_velocity#Cosmology" rel="nofollow">peculiar (i.e. non-Hubble) velocity.</a>
Further out is where you start to see redshifts in excess of peculiar motion; and there you need to start using standard candles of some sort.
Cepheid variables when visible, Supernova, globular cluster brightness functions, are all used, as well as some spectral methods: <a href="http://en.wikipedia.org/wiki/Cosmic_distance_ladder#Standard_candles" rel="nofollow">Cosmic distance ladder</a></p>

<p>Supernova measurements go the furthest out, highest redshift, but are <a href="http://www.astro.ucla.edu/~wright/sne_cosmology.html" rel="nofollow">still a bit of a can of worms as far as interpretation goes.</a></p>

CC BY-SA 3.0
2014-08-13T15:59:43.757Z
2014-08-14T16:29:39.787Z
2014-08-14T16:29:39.787Z
Wayfaring Stranger
<p>I am looking for basic data regarding red-shifting that  comes with reliable measure of distance of the emitting star.</p>

<observational-astronomy><redshift><raw-data>
Data for red-shifting
Maesumi
# Data for red-shifting

(Asked by: username_0 on 2014-08-12)

I am looking for basic data regarding red-shifting that comes with reliable measure of distance of the emitting star.

**Tags:** observational-astronomy, redshift, raw-data


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## 1 answers

### Answer by username_1 on 2014-08-13. Score: 3 | Accepted answer

Red shift is usually measured for galaxies rather than individual stars. Unless a star has just gone supernova, it's usually not bright enough to be seen even w the world's most powerful telescopes at the distances where cosmological redshift comes into play. [Hubble's law](http://en.wikipedia.org/wiki/Hubble%27s_law) operates over **large** distances; the expansion constant being 67.8 km/sec per megaparsec (3.3 million light years)
[Andomeda galaxy (M31)](http://en.wikipedia.org/wiki/Andromeda_Galaxy) is 2.54 million light years away, and although some individual stars are visible at that distance, the galaxy has a net **blueshift** of 0.001001 (303 km/sec) due to its [peculiar (i.e. non-Hubble) velocity.](http://en.wikipedia.org/wiki/Peculiar_velocity#Cosmology)
Further out is where you start to see redshifts in excess of peculiar motion; and there you need to start using standard candles of some sort.
Cepheid variables when visible, Supernova, globular cluster brightness functions, are all used, as well as some spectral methods: [Cosmic distance ladder](http://en.wikipedia.org/wiki/Cosmic_distance_ladder#Standard_candles)

Supernova measurements go the furthest out, highest redshift, but are [still a bit of a can of worms as far as interpretation goes.](http://www.astro.ucla.edu/~wright/sne_cosmology.html)


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