Look in the night sky and you will see
Many things that are shining brightly
Groups of smart people often measure me
To find the rate at which the celestials move away quickly
Step in and take a stand
If you're in front of me, we can go to faraway lands
But really, we'll still be in the same place
Yet we can make it seem like we went to space
I'm often used to help build things
Which might be strange because I don't even have limbs
Neither am I made of pure metal or alloy
I'm made on something used by a common schoolboy
Putting all of the above together
Make everything devoid of color
Then look at one then look at two
And you'll get some valuable clues
As those things are some of the many parts of me
Also know that keeping doctors away isn't my specialty
What am I?
To clarify a bit more, each of the first 3 clues are looking for a separate word, and once you have all 3 of these, the final clue should help you arrive to the answer. Also note that I'm not looking for an explanation of each line, but just a sentence or two explaining why each word you found fits with its clue.
Sorry if it's confusing, and if you have suggestions or edits or know better tags for these kinds of puzzles, don't hesitate to change anything.