Eye relief, ep's etc

[Ally8446]

Im 40+, served in Armed Forces as a weapons mech so why oh why cant I get my head round all this. Having a AM130 with a 10mm and 20mm supplied ep's would someone explain to me (laymans terms please) what I need to know about eye relief vs ep size (why does eye relief make a difference), do I really need a barlow ? Wide angle or not ? All I want to look at planets, nebula and some dso's. No interest in astrophotography (yet). Confused.com

[swamp thing]

Hi Ally

eye relief

The distance between the rear lens (the eye lens) of an eyepiece and the exit pupil . If this distance is too short, the eye will be uncomfortably close to the eye lens; if it is too long, it may be hard to keep the eye in the best position to view the image. In general, eye relief gets shorter as the focal length of the eyepiece decreases, but it is possible to design eyepieces of short focal length with good eye relief. Good eye relief is useful for spectacle wearers.

HTH

Regards Steve