Laurent, forget everything you have just read above.
Just take out a second Mortgage on your house, buy the most enormous Dob you can find (try about 26"), buy a big trailer to cart it around in to dark sky sites, buy a HUGE ladder so you can see in the eyepiece, then after you have done this exercise a few times, pack the scope away in the shed and just turn on the computer and look at the Hubble images
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