Newt or SCT for planets?

[Satchmo]

Originally Posted by Wavytone

Petr, for observing the planets, in increasing order of quality:
Short-focus Newtonians (typically f/5 or less) are intended for wide-field imaging, not high magnification. Adding barlows and/or ridiculously short eyepieces is about the worst solution for planetary observing.

(ast Newt = poor choice)

With respect, this sounds like thinking from 50 - 25 years ago .

In the evolving Newt market a telescope slower than F5 above 12" aperture is a rarity.

Televue Powermate focal extenders do not lose you any optical quality , so provided you keep your obstruction below 20% ( easy for a visual scope) , have good optics , and can keep your scope well collimated F4 to F4.5 , in a medium aperture, a Newt is the preferred choice as they are well ventilated. World renowned planetary imagers like Anthony Wesley and Trevor Barry both use 16" Newts in this focal ratio.

Even if you do not use an extender there are many long eye relief short FL EP's these days that are beyond reproach. There is much more information about collimation these days and low cost superb collimation tools make the job easy.

Mark

[Poita (Peter)]

I think he said his main aim was imaging and not visual, and that he has a mount that will take almost anything, so a giant newt may be a possibility.

I use my 9.25 and a powermate for planetary, I don't think my seeing is ever good enough for me to want to upgrade past a C11 really.

[Screwdriverone (Chris)]

Originally Posted by Satchmo

World renowned planetary imagers like Anthony Wesley and Trevor Barry both use 16" Newts in this focal ratio.

Mark

Ahh yes, but Mark should also make the point that for this size and F ratio mirror, it helps if the mirror is of exceptional standard, preferably made by a expert manufacturer.......

Know any Mr Suchting?



Cheers

Chris

[casstony]

The cheapity 16" f/4.5 Lightbridge I used recently gave sharp and contrasty views of Saturn and the big aperture gives greater colour saturation making different hues easier to see. The scope was easy to assemble and collimate and had none of the cooling issues I normally have with my SCT's. The lower tube/mirror is very heavy though.