Astronomical telescope refraction problem, an easy one

[alpyurtsever]

Homework Statement

1.a) Design an astronomical telescope with an angular magnification of +5 (pay attention to + sign !) and
length of 16 cm, i.e. compute fobjective and focular).

Homework Equations

M=-(f_objective/f_ocular)
L=f_ocular+f_objective

The Attempt at a Solution

f_objective=16-f_ocular

M=-(16-f_ocular)/f_ocular

f_ocular = -4 cm
f_objective= 20 cm

I have found like that, but it says that it is an astronomical telescope in the question, where am I doing wrong. Astronomical telescope must consist of 2 convergent lenses, isn't it?

 

[Redbelly98]

Astronomical telescope must consist of 2 convergent lenses, isn't it?

No, not necessarily. Your solution looks good