Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

BASIC EXTRAGALACTIC ASTRONOMY - Part 6: Galaxies, Discovery and Classification

  • Please log in to reply
2 replies to this topic

#1 rekokich

rekokich

    Viking 1

  • *****
  • topic starter
  • Posts: 938
  • Joined: 14 Sep 2014
  • Loc: Virginia

Posted 11 July 2020 - 10:52 AM

The only primary evidence available to an astronomer about a very remote object consists of photometric measurements, a spectrogram, and an image which is in many cases no more than a pinpoint of light. In this article we present basic cosmological concepts and simplified mathematical methods which allow an amateur to derive from this meager data a surprising number of physical properties of distant extragalactic objects with a precision of several percent within professional results.

Click here to view the article

#2 JohnBear

JohnBear

    Viking 1

  • *****
  • Posts: 596
  • Joined: 08 Jul 2017
  • Loc: Sandy, Utah

Posted 11 July 2020 - 12:20 PM

AT this time the links do not seem to be working. But I WILL definitely be following  this topic article.

 

Recently, while looking at some galaxy images, I suddenly realized that ALL of the stars (except for the pictured galaxies) I saw in the images were located very close within our own galaxy rather than randomly dispersed out to and beyond the target galaxies. This allowed me finally realize that there are tremendous voids of presumably empty space between galaxies. That was a rather simple but unexpected personal epiphany for me. Just looking is a pleasant experience, but learning to understand what you are seeing is so much more!

 

It seems obvious now, but I had never thought about it that way before (I just appreciated the beautiful images) - and I have a technical background and consider myself as sort of a "lay scientist".  LoL! 

 

I definitely want to learn more and be able to do some basic calculations to help conceptualize what I am viewing in 3 (or more) dimensions. If this topic continues, I will be referring this topic to other amateur astronomers I know.  So please keep it coming!


  • scottinash, Cosmic_Lox and GaryShaw like this

#3 scottinash

scottinash

    Vostok 1

  • *****
  • Posts: 182
  • Joined: 31 Jul 2004
  • Loc: Tennessee, USA

Posted 22 July 2020 - 08:10 AM

Excellent resource!   Thank you.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics