Placement point

[MagicalMuggle]

I've currently got a telescope that has the eyepiece retracting from the other end of the lense (like the blue one in the photo) but have seen others where the eyepiece is practically on top of the lense. I was hoping someone could tell me some pros and cons for having the eyepiece so much further up

[Stargazer33]

Hi and welcome to SGL!

The one that you have is called a refractor and uses only lenses to form the image. The other one is called a Newtonian and uses mirrors to form the image. A quick Google of these terms will provide you with lots of information. 

[John]

Hi and welcome to the forum.

These drawings show the optical arrangements within these different scope designs and I hope explain why the eyepiece position is different. A third design is shown at the bottom - the schmidt-cassegrain. This has an eyepiece position similar to the refractor (at the top):

Here is an article which gives more detail about the strengths and weaknesses of these designs (and others):

https://skyandtelescope.org/astronomy-equipment/how-to-choose-a-telescope/

 

[MagicalMuggle]

Stargazer33, I had a look but couldn't find a massive amount to help a simple minded person like myself. In short, it didn't make much sense. Thanks anyway though bud. 

John, the link you gave altho at times went straight over my head (pun intended 😁) it's certainly helped me understand things better. Cheers for that mate 

[Alan64]

A refractor, along with a Maksutov-Cassegrain, has the focusser at the rear, which is actually, in my opinion, more user-friendly...

With a reflector(Newtonian), the focusser, with the eyepiece inserted, has to be at the front of the tube on the side.  That is how it was designed by Issac Newton over 300 years ago...

There is no advantage, no pro, a con instead, with that design, for observing is best conducted whilst seated.  Form simply follows function in that. 

You cannot change either design.  They're "set in stone", forever...

Any questions?