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80mm ED f/10 FPL-53 & Lanthanum

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#76 m9x18

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Posted 11 February 2020 - 10:14 PM

Oh my gosh that's a beautiful picture! That moon shot looks fantastic!    



#77 johninderby-uk

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Posted 13 February 2020 - 07:53 AM

Replaced the white foam blocks in the case with pick’n’pluck foam. With the handle fitted to the scope it has to lay on its side in the case.

 

Find the case is more suited to storing the scope in. If carrying it around a lot would prefer a heavier duty case .🤔

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#78 johninderby-uk

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Posted 14 February 2020 - 12:44 PM

Luggage straps

 

While the case is OK for storage wanted a bit of extra security for carrying it around. Never trust the latches on cases like these so better safe than sorry. The straps were cheap on Amazon and no need to get a heavier duty case now.

 

     John

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Edited by johninderby-uk, 14 February 2020 - 12:47 PM.

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#79 m9x18

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Posted 14 February 2020 - 12:48 PM

Luggage straps

 

While the case is OK for storage wanted a bit of extra security for carrying it around. Never trust the latches on cases like these so better safe than sorry. The straps were cheap on Amazon and no need to get a heavier duty case now.

 

     John

Good thinking!



#80 calypsob

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Posted 16 February 2020 - 09:58 AM

How much are these things? Unless they have a special reducer, I would assume this is strictly a visual ota.



#81 johninderby-uk

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Posted 16 February 2020 - 10:05 AM

Not aware of a dedicated flattener for it. It really is a visual scope although should be good on lunar and planetary AP.



#82 25585

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Posted 16 February 2020 - 02:41 PM

FLO sell a reducer/flattener but its optimised for F5-F7 scopes.



#83 aa6ww

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Posted 16 February 2020 - 10:20 PM

looks like a perfect 80mm refractor. I like the F10. Very nice. Can it be bought in the US from a US dealer?

 

...Ralph



#84 desertlens

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Posted 16 February 2020 - 10:36 PM

looks like a perfect 80mm refractor. I like the F10. Very nice. Can it be bought in the US from a US dealer?

 

...Ralph

As far as I can see (and I've been looking), no US vendor has picked up on this one yet. An 80mm ƒ10 ED doublet has a lot of potential as a well corrected solar system and double star instrument. Let's hope...


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#85 daquad

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Posted 18 February 2020 - 11:50 AM

Beautiful scope, but I'd like a 100 mm f/10 version with the same build quality and R&P focuser.  Maybe in the not too distant future?

 

Dom Q.


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#86 Tyson M

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Posted 18 February 2020 - 11:51 AM

Beautiful scope, but I'd like a 100 mm f/10 version with the same build quality and R&P focuser.  Maybe in the not too distant future?

 

Dom Q.

 

The TS 102 F11 doesnt tick that box?

 

Unless you mean FPL53 + lanthanum glass.


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#87 daquad

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Posted 18 February 2020 - 11:53 AM

The TS 102 F11 doesnt tick that box?

 

Unless you mean FPL53 + lanthanum glass.

That's what I mean.


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#88 25585

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Posted 20 February 2020 - 03:18 PM

Would there be much benefit of F10 over F9? 



#89 daquad

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Posted 21 February 2020 - 10:55 AM

Would there be much benefit of F10 over F9? 

Not much, but what I like about the Stella Mira is the build quality.  The 80 mm looks like it is worth the higher price.

 

Dom Q.


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#90 johninderby-uk

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Posted 21 February 2020 - 11:08 AM

Similar build quality to William Optics.

 

A little something arrived that should help with high mag in this scope. 

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#91 astro42

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Posted 21 February 2020 - 02:30 PM

Nice,

I just picked up one of those zoom eyepiece but haven't had a chance to try it yet.



#92 johninderby-uk

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Posted 21 February 2020 - 03:37 PM

Had one of them before. A great eyepiece that isn’t a compromise despite being a zoom. 

 

Arrived with typical weather for a new purchase though. Not too cold tonight at 10c (50f) but a bit wet.

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Edited by johninderby-uk, 21 February 2020 - 03:49 PM.


#93 m9x18

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Posted 21 February 2020 - 03:55 PM

Excellent choice! I have that eyepiece too. It's very versatile and should be a part of every backyard astronomer's inventory. 



#94 GlenM

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Posted 22 February 2020 - 05:32 AM

Had one of them before. A great eyepiece that isn’t a compromise despite being a zoom. 

 

Arrived with typical weather for a new purchase though. Not too cold tonight at 10c (50f) but a bit wet.

It's been terrible weather John. I'm on the verge of packing it in due to the weather. I would like to hear about the performance on double stars when the weather clears up. 

 

Glen.



#95 25585

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Posted 22 February 2020 - 07:38 AM

January had some good nights. Feb literally a wash-out. March might not be much better. I hope April & May, galaxy season, bring back clear skies.  



#96 Gregory Gross

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Posted 19 May 2020 - 12:43 PM

Everyone talks about color correction, as if it's the only thing in a refractor, but there are other reasons to go with a long focal length, other than achieving a bit better color correction:

 

- spherical aberration gets much easier to control

- spherochromatism becomes MUCH easier to control

- curves get gentler, making manufacturing easier, making it much more likely that the lens is of high quality

- collimation becomes much less critical

- an objective with gentler curves suffer less from aberrations during cooldown, because a difference in temperature between the front and rear lens(es) introduces less spherical aberration and spherochromatism in an objective with gently curved lenses, than one with strong curves. 

 

 

Clear skies!
Thomas, Denmark

One question that occurred to me along these lines is this: what is the difference between the performance of a long-focus refractor with a natively long focal length and slow focal ration vs. stopping down a larger-aperture but faster focal ratio refractor down to the same focal ratio as the slower smaller-aperture scope? For example, what difference in performance would one see if one looked through this 80mm f/10 Long Perng refractor vs, say, a SkyWatcher 100mm ED f/9 scope with an aperture mask that brought it down to an 80mm f/11.25 scope?

 

I'm curious to know if the scope with 80mm optics designed to operate at f/10 would outperform the 100mm f/9 scope stopped down to 80mm for the reasons that Thomas outlined in his post from this past February.



#97 Jond105

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Posted 19 May 2020 - 12:54 PM

One question that occurred to me along these lines is this: what is the difference between the performance of a long-focus refractor with a natively long focal length and slow focal ration vs. stopping down a larger-aperture but faster focal ratio refractor down to the same focal ratio as the slower smaller-aperture scope? For example, what difference in performance would one see if one looked through this 80mm f/10 Long Perng refractor vs, say, a SkyWatcher 100mm ED f/9 scope with an aperture mask that brought it down to an 80mm f/11.25 scope?

 

I'm curious to know if the scope with 80mm optics designed to operate at f/10 would outperform the 100mm f/9 scope stopped down to 80mm for the reasons that Thomas outlined in his post from this past February.

This is just my opinion, both being longer focal length ED doublets with great glass, not much. Though the stopping down of the 100ED, may be a little better as it increases the focal length. Obviously not as wide a view. Owning 3 100ED’s, I can say all were great. Minimal SA and zero CA. I doubt the 80 would best it. Nor do I think the 100 stiopped would best the 80. Though I never looked through the 80. 


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#98 SeattleScott

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Posted 19 May 2020 - 01:14 PM

As far as I understand a 100mm stopped down to 80mm F10 would perform identical to a 80mm F10 assuming same glass types and quality. I don’t think there is really an advantage to operating at native F ratio compared to stopping down to the same F ratio. Other than a 80mm will be lighter and more portable than the 100mm.

Scott
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#99 Jond105

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Posted 19 May 2020 - 01:18 PM

As far as I understand a 100mm stopped down to 80mm F10 would perform identical to a 80mm F10 assuming same glass types and quality. I don’t think there is really an advantage to operating at native F ratio compared to stopping down to the same F ratio. Other than a 80mm will be lighter and more portable than the 100mm.

Scott

Though the 100Ed stopped down does get a completely different f ratio. 


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#100 johninderby-uk

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Posted 19 May 2020 - 01:28 PM

The 80mm f/10 has better optics and will give a sharper more contrasty image than the 100mm. Probably not a lot in it but think the superior optics of the 80mm would let you pick out finer detail. 

Love the build quality of the 80mm Just as good as William Optics.

 

Basically it’s just a newer generation of scope vs one that has been around for a while. What will Skywatcher do to up their game? 


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