3 replies to this topic

[oszolom]

Hi.

I bought Smidt Newton 10" by Meade.

It's F=4 telescope.

What do you think, which eyepiece will be good for this telescope?.

I think about 3 pcs.

20-25mm.

9-11mm

6-7mm.

[J.LAMBIE]

Yes.      And barlow.

[SeattleScott]

Seems like a good plan. Just add a barlow or short FL like 3mm to crank it up for planets. I loved my ES 24/82 with my SN.

Scott

[vkhastro1]

This is my take on the Schmidt-Newtonian.

 

I own the Meade SN10 (10” f/4), SN8 (8” f/4) (x2) and the Celestron Comet Catcher 5.5” f/3.64 (x4 - 2 single units and a pair in a Bino-Telescope).

I have owned my 1st Celestron Comet Catcher since its 1st release in the early 80’s and my Meade 10” when it was 1st released. I have over 35 years of experience with this design. All have been variously modified for visual use - upgraded Moonlite dual rate focuser, internal  flocking, flocked dew shields, anti-dewstraps, optimal collimation, etc. 

 

It is a dedicated RFT (Rich Field Scope) and not a planetary scope.

The central obstructions vary from just 30% (SN6 which is f/5) to about 38% (SN8). 

If you are looking for a planetary Catadioptric scope look to the Mak-Newtonian (MN) f/6 versions by Ceravolo and Intes).

I have several MN from 5” to 8” - they rival similar size true APOs on lunar/planetary due to their ~16%-20% central obstructions.

 

The f/4 Schmidt-Newtonians (SN) have the coma of a f/5 Newtonian. 

An f/5 Newtonian is definitely improved by a coma corrector - so is the SN 

I prefer the Baader MPCC (Multipurpose Coma Corrector) because there is no increase in f/ratio - f/4 is f/4.

A Televue Paracorr works perfectly but the f/ratio is increased by 15% - f/4.6 for SN8 and SN10

 

I am in my mid - 60s, so I prefer a maximum exit pupil of 5.5mm (younger eyes go to 7mm).

I also prefer wider AFOV eyepieces, the wider the better, the longer the eye relief the better (I do not wear my glasses to observe) - these eyepieces push the RFT viewing experience to another level in the SN.

 

The following eyepieces 2” (with Baader MPCC) are excellent low power eyepieces - TV Nagler 22mm and 17mm Type 4, APM 20mm 100°, and my absolute favourite ES 17mm 92° (Also amazing without a coma corrector)

Excellent 1.25” low power eyepieces with MPCC - TV 24mm Panoptic, APM 24mm FF, TV 22mm Panoptic, Vixen/Orion 

22mm LVW (also without MPCC), TV 19mm Panoptic 

 

My mid power favourites (with or without MPCC) - 2” ES 12mm 92° Or APM 13mm 100°

1.25” - Doctor 12.5, APM 12.5mm 84°, Baader Morpheus 12.5mm

 

My Meade SN8s both optically start to breakdown (mainly due observing conditions, not the Optics) at 6mm, my SN10 at 7mm. At higher powers I prefer the APM 9mm 100°, Baader Morpheus 9mm and 6.5mm

 

Other excellent eyepiece choices are the TV Ethos and Delos and Pentax XW and XL 

 

The Schmidt-Newtonian is one of my favourite telescopes designs !