The light collecting ability of the 114mm Newtonian is equal to an 91.2mm refractor, due to the secondary mirror obstruction. The 114mm Newtonian has no chromatic aberration, because Newtonians never have any. They reflect light instead of refracting (bending). This particular reflector uses a spherical primary mirror as do most inexpensive Newtonians which causes spherical aberration. So, the center third of the image is focused, but the image is slightly out of focus beyond that. And, at f/4.4, the Newtonian will suffer from coma, unless it is perfectly collimated. Coma and spherical aberration are both reduced by a longer focal length, which is why you will see f/7 to f/9 inexpensive reflectors. I will soon be reviewing a Aomekie 76/700 f/9.2 Newtonian. Thanks for your thoughts. 😉
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Would be interesting to see a comparison video with the 90 mm F10 achromat versus the 114 mm newtonian :)
The light collecting ability of the 114mm Newtonian is equal to an 91.2mm refractor, due to the secondary mirror obstruction. The 114mm Newtonian has no chromatic aberration, because Newtonians never have any. They reflect light instead of refracting (bending).
This particular reflector uses a spherical primary mirror as do most inexpensive Newtonians which causes spherical aberration. So, the center third of the image is focused, but the image is slightly out of focus beyond that.
And, at f/4.4, the Newtonian will suffer from coma, unless it is perfectly collimated. Coma and spherical aberration are both reduced by a longer focal length, which is why you will see f/7 to f/9 inexpensive reflectors. I will soon be reviewing a Aomekie 76/700 f/9.2 Newtonian.
Thanks for your thoughts. 😉
A very nice, easy to use beginner telescope.