Pros:
- More forgiving collimation, which often results in better 'real-world' performance on average
- Lack of coma means larger sharp, diffraction-limited field. This is particularly important if the scope is a dob as your target spends most of its time NOT in the center of the field.
- With longer focal lengths you can get high magnifications without having to use barlows, spendy ultra-short f.l. eyepieces or other such optical leverage that put more glass between you and your target.
- Longer scopes are easier to baffle effectively just because it's harder for light to sneak down a longer tube (or cloth-covered truss) which improves contrast.
- You can use a smaller secondary obstruction but IMHO this is probably the least important of long f.l. advantages.
Cons:
- Portability. Not a petty concern with the aperture & focal ratio you're considering!
- Eyepiece height on this bad boy will also not be a trivial matter. Safety First!
- More forgiving collimation, which often results in better 'real-world' performance on average
- Lack of coma means larger sharp, diffraction-limited field. This is particularly important if the scope is a dob as your target spends most of its time NOT in the center of the field.
- With longer focal lengths you can get high magnifications without having to use barlows, spendy ultra-short f.l. eyepieces or other such optical leverage that put more glass between you and your target.
- Longer scopes are easier to baffle effectively just because it's harder for light to sneak down a longer tube (or cloth-covered truss) which improves contrast.
- You can use a smaller secondary obstruction but IMHO this is probably the least important of long f.l. advantages.
Cons:
- Portability. Not a petty concern with the aperture & focal ratio you're considering!
- Eyepiece height on this bad boy will also not be a trivial matter. Safety First!
