Prototype Sky-Watcher Evolux ED Refractors

[barkingsteve]

Excuse my ignorance but i thought the focal ratio was the focal length divided by the aperture ?  these numbers are a little confusing to me.

 

Technical Specifications:

• Optical Design - Refractor 
• Aperture - 82mm
• Focal Length - 400mm (without reducer)/ F=360 (with optional reducer)
• Focal Ratio - f/6.4 or (f/5.8 with optional reducer)
• Weight - 2.6kg

Edit: looks like a mix up, i think they are the 62mm version focal lengths and ratio.

Edited March 1, 2020 by barkingsteve

[Dave Lloyd]

And me! Does it have some internal restrictor or baffle? 

Edited March 1, 2020 by Dave Lloyd

[Dave Lloyd]

Good spotting. 

[Adam J]

On 29/02/2020 at 01:27, Shaun_Astro said:

https://www.altairastro.com/skywatcher-evolux-82ed-refractor-telescope---ota-only-2575-p.asp

Altair have the page up for these fracs. The 82's glass type isn't listed (al-la Evostar 72ED) therefore is unlikely Ohara FPL-53 of the Evostar 80, or even fp-51? It is listed as improved ED glass. Interesting but I don't think this will be a step up from the Evostar 80 ED?

Likely to be fcd100 and that is good glass

[Rick_It]

IMHO, this is the new ED glass from CDGM, the H-FK71. It is somewhat in between FPL51 and FPL53, but closer to FPL53. I've already seen SW using terms like new or improved ED glass, and this glass is actually new and improved from H-FK61 (the previous "ED" from CDGM). And, from a marketing perspective I can understand that they don't want to disclose this glass, as (i) it is slightly inferior to FPL53 (and FCD100), (ii) it's new-unproven and (iii) not from the traditional glassmakers (Ohara, Hoya, Schott).

Edited March 2, 2020 by Rick_It

[Adam J]

1 hour ago, Rick_It said:

IMHO, this is the new ED glass from CDGM, the H-FK71. It is somewhat in between FPL51 and FPL53, but closer to FPL53. I've already seen SW using terms like new or improved ED glass, and this glass is actually new and improved from H-FK61 (the previous "ED" from CDGM). And, from a marketing perspective I can understand that they don't want to disclose this glass, as (i) it is slightly inferior to FPL53 (and FCD100), (ii) it's new-unproven and (iii) not from the traditional glassmakers (Ohara, Hoya, Schott).

Well that (H-FK71) looks similar in performance to OK-4 and that does very well for LZOS.

[Shaun_Astro]

The current ED80 uses FPL-53, and retails at £379. The Evolux features effectively the same glass then, but is listed as $1500 AUD, that's £750, twice the price.

[Skyline]

Let's wait and see what skywatcher offer. Sure it will be competitive.

Has FLO got an update when they will hit the uk market bearing in mind with the Corona outbreak ?

Edited March 12, 2020 by Skyline

[Shimrod]

On 12/03/2020 at 12:11, Shaun_Astro said:

The current ED80 uses FPL-53, and retails at £379. The Evolux features effectively the same glass then, but is listed as $1500 AUD, that's £750, twice the price.

 

I think you need to compare that to the price of the ED80 in Australia - that's $1399 (or £700) for the £485 kit over here. If you take the same deduction (FLO sell the tube only by  splitting kits), then you are comparing $1104  to $1500. A big chunk of that cost could be the upgraded focuser, depending of course on how good it is.

[Fozzie]

Just noticed a few prices, from an Italian based astro supplier.. links from a recent CN post..

Ta

Fozzie

[Chris]

The 62 looks very keenly priced!

[Shaun_Astro]

£730 to replace a £375 80 Ed. Jeez I might buy the evostar if it's being discontinued. 

[Shimrod]

11 minutes ago, Shaun_Astro said:

£730 to replace a £375 80 Ed. Jeez I might buy the evostar if it's being discontinued. 

I suppose it depends how much the focuser has been improved as well as the optics. I recently bought an 80ED but upgraded the focuser at the same time - that was £675 (OTA plus Baader Steeltrack + adapter) to accommodate my camera.

[Rick_It]

The focuser cannot costs too much, as the same unit is included in the 300€ Evolux 62mm. The difference in price between the two is quite strange. The price of the 62mm ED makes sense: same price as the Evostar 72mm, with 10mm less aperture but a better focuser and retractable dew shield. It's the 82mm price which is strange. In principle, it could eventually be the case that the 82mm is using a better glass (like FPL53 instead of FPL51). But consumers cannot consider that, as SW refuses to disclose this key technical characteristic.

Edited April 17, 2020 by Rick_It

[Shaun_Astro]

1 hour ago, Rick_It said:

The focuser cannot costs too much, as the same unit is included in the 300€ Evolux 62mm. The difference in price between the two is quite strange. The price of the 62mm ED makes sense: same price as the Evostar 72mm, with 10mm less aperture but a better focuser and retractable dew shield. It's the 82mm price which is strange. In principle, it could eventually be the case that the 82mm is using a better glass (like FPL53 instead of FPL51). But consumers cannot consider that, as SW refuses to disclose this key technical characteristic.

The evostar 80 uses fpl53, the Evolux probably uses a new glass discussed earlier, which isn't quite as good. as FPL53 apparently.

 

It seems very expensive if seems but then, maybe the 80ed was under priced. The WO 81apo is £799, and that's a fpl53 doublet. The lens design is perhaps better also than the 80ed. 

Edited April 17, 2020 by Shaun_Astro

[Merlin66]

IMHO the FPL 51 v’s FPL 53 is all marketing hype....

The average punter will be hard pressed to see any difference......

[Chris]

1 hour ago, Merlin66 said:

IMHO the FPL 51 v’s FPL 53 is all marketing hype....

The average punter will be hard pressed to see any difference......

If this is true it would save us all a lot of money! At low mag and dim object visual maybe it is true? for any kind of imaging I think FPL51 glass looks a bit more 'bloaty' to my eye. 

[Merlin66]

The FPL51/53 is just one of the elements in the lens design........

[Skyline]

The old William Optics ZS66SD - White trim model with black focuser was equipped with FPL51 glass but the mating element must have been a good one as there was no bloat or any blue cast around the stars. 

Similar results I found with the SW ED72, wonderful optics no blue casting around the stars but the build quality could be better.

Other options are on the market, but I am still weighing up should I need to buy another scope?

That's why I stuck with my Celestron ED Refractors and probably still will.

You could really have a good refractor optic with glass other then fpl53 so long as the mating element(s) are of good optical quality and correction  as well.

Take for example the WO Megrez 72, the original design of the scope belonged to long pern (probably still does). It was equipped with FPL51 with another glass element but showed some blue  bloat around stars in images (I know because I had one).

Another telescope manufacturer now manufactures them with a modified lens cell which does not pinch the optics with FPL53 and NBM51 glass, looking at the test images there's now no blue bloat and more likely better now for the optics to handle using a scope with a quality reducer bringing the scope down to f4.7 from f6.

It's all swings and roundabouts. Marketing Hype is included for free !

Just my 2pennies worth.

Edited April 17, 2020 by Skyline

[Chris]

2 hours ago, Merlin66 said:

The FPL51/53 is just one of the elements in the lens design........

That's correct, and as you know you can't bring all wavelength of light to the same focal point with a doublet. However, it's easier to come close with high refractive index glass right?

Other variables of course include aperture and focal length (focal ratio), and whether it's a doublet or triplet, and the optical figure etc because you can make a very well corrected scope with fpl51 if it's a triplet.

All other things being equal, shouldn't fpl53 do a better job?

The reason I'm arguing the toss is because I've always been put off cheaper fpl51 ED scopes because the reviews highlight that they are more semi apo, and the images taken with them don't look pin sharp to me.

Having said this I would be happy with very smaller ED scopes having fpl51 because even very small aperture achro's show very little CA. The online aperture and focal length chart that often crops up demonstrates this.  

Edited April 17, 2020 by Lockie

[Rick_It]

In 102mm f11, nobody I think could spot the difference between and FPL51 and an FPL53 variant. In a 102mm f7 (where we have both the FPL51 and the FPL53 doublets) I think this difference is much larger.

[Skyline]

In smaller apertures maybe, as you go bigger its becomes more apparent.

[Adam J]

I really want one of these when are they going to get here!

[Skyline]

When skywatcher decides it's ready to release. From the marketing point of view, its stoking the fire as they say !

But I have noticed another retailer in the uk has released their own version of the ed72 with fpl53 and comes with a front collimatable lens cell also with stand offs not like the mounting issues what the WO73 suffers from.

Interesting times !

[AstroRuz]

I remember seeing this photo a while ago. As a huge Sky-Watcher fan I hope they're real. I'd like both thanks. Proper "Shut up and take my money" moment.

Well... as long as the specs make sense at least. I  agree with Chris - a scope that looks nice is important to me as well as its specs. Even though we normally image at night, we enjoy sharing photos of our rigs, right?

 

Plus it would match the green and white of my EQ6-R Pro...