Whats the difference??

[Plumb71]

Hi,

In relation to my earlier posts, is there much difference between the explorer 150p and the explorer 150PL, apart from the length, PL is f8 and the P is f5 would these differences be that noticable to a novice?

[AKB]

These different focal lengths would give you a different magnification and field of view for any given eyepiece.  So, yes, quite some difference. 

[Plumb71]

3 minutes ago, AKB said:

These different focal lengths would give you a different magnification and field of view for any given eyepiece.  So, yes, quite some difference. 

So which one would be better?

[John]

Speaking generally, the F/8 would be better for viewing the planets, the moon and double stars and the F/5 would be a better deep sky scope because it can show a wider field of view.

The F/5 scope does not need quite such a heavy duty mount to hold it steady. Colimation is more forgiving in an F/8 newtonian and lower cost eyepieces perform slightly better at F/8 than they do at F/5.

 

[Ruud]

The f8 would be better on planets. It has less coma, less curvature of the focal plane and can be made with a smaller secondary (not sure if this is actually done), which means a smaller central obstruction.

The f5 gives wider views with less magnification using the same eyepieces and would be more of a rich field telescope.

 

[AKB]

Depends what you want to view/image.   I’m afraid that “it depends” will be the answer to many question you may have!

To help decide, you should try out some different options with a field-of-view calculator such as

http://astronomy.tools/calculators/field_of_view/

or

http://www.12dstring.me.uk/fovcalc.php

Tony

 

Edited July 24, 2019 by AKB