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I posted on my Twitter a snapshot of few amazing galaxies, and someone asked about their distances.

I had the coordinates for these galaxies, so I could use the SDSS Navigate tool to see if the distances to these galaxies have been measured.

I input the coordinates in the ra and dec, and the object appears in the image view of the sky.

For example, Galaxy A has a distance, because someone measured its spectrum and calculated a redshift.
You can mark the box next to “Objects with spectra”, and red squares will appear next to the objects with spectral information, which is necessary to measuring the distance to that object.
By clicking on the object of interest and then on “explore” option in the menu to the right of the image, I get to find the redshift of the galaxy, along with other information.

Redshift is a way astronomers represent distance.
The larger the redshift, the further is the object from the observer on the Earth.
You can translate it to distance measurement with this calculator – NED Cosmology Calculator.

For example, for Galaxy A, I input for redshift z=0.092 in that calculator, chose the “flat” universe model, and left all the other parameters as default values. And the distance is about 1.4 Giga-light years (or 424 Mpc).

I put here the links to 5 galaxies in these fields within SDSS.

Galaxy A
z = 0.092    

Galaxy B
unknown redshift based on SDSS data
no spectrum in the SDSS database

Galaxy C
I used a DR17 version of the SDSS Navigate tool, because it had an error for this object in the DR16 version
z = 0.4

Galaxy D
also unknown redshift based on SDSS data

Galaxy E
also unknown redshift based on SDSS data

Let your curiosity lead you an a journey to explore galaxies on your computer, using this SDSS Navigate tool, happy browsing!

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