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Mewlon 180 for NV

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#1 bdg

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Posted 16 June 2019 - 01:47 AM

My existing scopes are in a relocation companies storage, I only have my Kowa spotter and recently got a Mewlon 180 f12/2160mm to use this season. Any idea if I can use the Mewlon for NV? Perhaps with a  Takahashi 0.8x  reducer  @f9.8, It’s setup now with a Baader T2 prism with 1.25” EP holder. What will be the image scale for nebulae, I suspect galaxies are not possible due to narrow focal length. 

 


Edited by bdg, 16 June 2019 - 01:53 AM.


#2 bobhen

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Posted 16 June 2019 - 06:38 AM

I use a Mewlon 210 and it is great with NV, especially for the smaller objects or any object like globulars that need image scale/magnification.

 

I use an Astro-Physics diagonal and a 2” Antares .7 reducer to get around F8. I also use the native FL as well.

 

Depending on how much light path the prism diagonal uses, and if you use an aftermarket focuser, you may or may not need a mirror diagonal with a shorter light path. The AP diagonal has a short light path.

 

I screw the 2” reducer into the bottom of the 1.25” to 2” adaptor that comes with most diagonals. This works fine.

 

I’ve had my best views ever of the core of the Orion Nebula, M27, faint globulars, etc. with the Mewlon and NV.

 

Any object that fits in the field will look great. Most galaxies, planetary nebula, globular clusters etc. will easily fit in the field.

 

Some people here use Celestron C11s with no problems as well. 

 

Bob


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#3 bdg

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Posted 16 June 2019 - 11:11 AM

I use a Mewlon 210 and it is great with NV, especially for the smaller objects or any object like globulars that need image scale/magnification.

 

I use an Astro-Physics diagonal and a 2” Antares .7 reducer to get around F8. I also use the native FL as well.

 

Depending on how much light path the prism diagonal uses, and if you use an aftermarket focuser, you may or may not need a mirror diagonal with a shorter light path. The AP diagonal has a short light path.

 

I screw the 2” reducer into the bottom of the 1.25” to 2” adaptor that comes with most diagonals. This works fine.

 

I’ve had my best views ever of the core of the Orion Nebula, M27, faint globulars, etc. with the Mewlon and NV.

 

Any object that fits in the field will look great. Most galaxies, planetary nebula, globular clusters etc. will easily fit in the field.

 

Some people here use Celestron C11s with no problems as well. 

 

Bob

Thanks Bob, I don’t have a 2” diagonal. I am using Baader T2 prism  which has the shortest light path with zwo adapter. If Antares reducer works I may skip buying the Tak reducer which is $$$.

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#4 bdg

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Posted 16 June 2019 - 11:48 AM

I think I can screw in the 2” Baader nose piece directly by removing Takahashi visual back adapters. Question is given it’s a T2 Prism with ~55mm measured light path (Baader claims 38.5mm) EP may not come to focus without spacers or 2” reducer can help add some optical path to bring the EP into focus.

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Edited by bdg, 16 June 2019 - 11:49 AM.


#5 bobhen

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Posted 16 June 2019 - 12:55 PM

I also use a Moonlite 2-speed focuser with my Mewlon 210 plus the 2” AP diagonal and the .7 reducer and the Micro still comes to focus, which is one of the benefits of moving the primary to achieve focus.

 

Belo is an image of the optical train that I use with my 4” refractor (left) and it’s the same train that I use with my Mewlon 210 except of course the Mewlon + Moonlite focuser takes the place of the refractor + GSO focuser.

 

Focuser then 2” AP diagonal then the .7, 2” Antares reducer screwed onto the bottom of 2” to 1.25” diagonal adapter then the Micro with a c-mount to 1.25” adapter and either a Pass or Ha filter on the end of the adaptor.

 

Whatever system you use to get to focus, your Mewlon 180 will deliver the goods with NV.

 

Bob

 

 

 

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#6 bdg

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Posted 16 June 2019 - 01:46 PM

I also use a Moonlite 2-speed focuser with my Mewlon 210 plus the 2” AP diagonal and the .7 reducer and the Micro still comes to focus, which is one of the benefits of moving the primary to achieve focus.

 

Belo is an image of the optical train that I use with my 4” refractor (left) and it’s the same train that I use with my Mewlon 210 except of course the Mewlon + Moonlite focuser takes the place of the refractor + GSO focuser.

 

Focuser then 2” AP diagonal then the .7, 2” Antares reducer screwed onto the bottom of 2” to 1.25” diagonal adapter then the Micro with a c-mount to 1.25” adapter and either a Pass or Ha filter on the end of the adaptor.

 

Whatever system you use to get to focus, your Mewlon 180 will deliver the goods with NV.

 

Bob

Those moonlite focusers are nice, do you any advantage using it instead of stock Tak focuser. I have a Moonlite focuser on my Lunt 60ha it’s a nice kit but it replaced not so great stock focuser.



#7 bobhen

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Posted 16 June 2019 - 02:28 PM

Those moonlite focusers are nice, do you any advantage using it instead of stock Tak focuser. I have a Moonlite focuser on my Lunt 60ha it’s a nice kit but it replaced not so great stock focuser.

The stock Mewlon focuser on the Mewln 210 and I presume the 180 is fine but the addition of an aftermarket focuser like a Moonlite or Feathertouch has a couple of advantages.

 

First: they eliminate any image shift when focusing.

 

Second: when using high power (and with a Mewlon you will want to use high power when you can) with a 2-speed focuser you can really dial in exact focus by making very small adjustments.

 

Absolutely necessary, no. But worthwhile, definitely.

 

Bob


Edited by bobhen, 16 June 2019 - 02:28 PM.


#8 The Ardent

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Posted 16 June 2019 - 02:43 PM

Hmmm

https://www.cloudyni...-250crs-and-nv/

https://m.dpreview.c.../thread/3968972

https://m.youtube.co...fset=-420&tsp=1

#9 bdg

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Posted 16 June 2019 - 03:05 PM

Thanks, with a tracking mount & reducer, this m180 setup will be an good NV scope.




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