FreeLists / az-observing / [AZ-Observing] Re: Mars Sunday night

[Jeff Hopkins <phxjeff@xxxxxxxxxxx>]

>Rick R. wrote:
>
>   Another way of reducing the glare of bright planets is to use an "aperture
>stop" on the newtonian.--clip to save sapce--
>

While that certainly does reduce the light, it also reduces the 
resolution. It is usually better to reduce the light via a full 
aperture filter either on the objective (a must for solar observing) 
or on the eyepiece. This reduces the light while retaining the 
resolution.

Some feel that the aperture reduction helps in poor seeing. I believe 
it only helps by reducing the resolution. Kind of fools you into 
thinking smaller is better, when it really is not.

Now I would argue a clear aperture (e.g., a refractor or off axis 
Newtonian) is better than an obstructed one for planetary work!

Jeff
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