Henry,
A 32mm 1.25" eyepiece will give you a 1.1° TFOV with that 127 Mak. That's as wide a TFOV you can get with that scope. This is more than 50% over what your 20mm plossl gives at 0.7°
That 5" Mak is a very good scope. Maks and SCT's are unfairly touted as being poor for DSO's. Nonsense. Ok, so they don't have the same TFOV as say a 5" f/5 Newt or frac, but the image they throw up is very good. And no chromatic aberration or the challenge that coma can present to some people too.
Some people will also fret about the corrector plate dewing up. Don't fret! While the norm is to wait for our gear to cool to ambient temp, there is a change in thinking when it comes to Maks and SCT's - DON'T let them cool!
When you let a Mak or SCT cool, the metal tube cools much quicker than the mirror and baffle inside the OTA. As a result a heat plume forms inside the tube because of the heat differential.
So, if you insulate the OTA, and don't let the scope cool, no heat differential forms and so no heat plume is generate, AND you can rip high magnification from the scope straight away!
I've been insulating my SCTs and Maks for a number of year now. No waiting for cooling. I set up when I can, and I don't have time to fluff around waiting for a scope to cool over 2 hours. Instead those two hours are actually productive hours for me.
,
,
This won't stop dew forming on the corrector, but it will greatly extend the amount of time the corrector remains dew-free. And when dew does form you can gently use a hair drier to dry it off.
Just one thing about making an insulating wrap - don't make it out of a black or similarly dark material. Black cools to below ambient temperature (regardless of the material), and it will work against you, actually allowing the scope to cool rather than insulate it. Some people have even made these wraps out of those cheap aluminized car windscreen shades.
Alex.
