Skywatcher ED150/1200 APO. Is this real or fake news?

[glend]

Just noticed that Andrews has a note posted concerning the arrival of a Skywatcher ED150, 1200mm (f8) fl APO due in late January. Of course, Skywatcher has had an old 150/1200 Achtomat for many years, but the Andrews website says its an Apochromatic. An internet search fails to uncover any news concerning this type of scope, and the Esprit 150 APO is a f7 triplet using FPL-53 glass.
Is this simply an advertising mistake in describing the Esprit or is there actually a 150 m f8 APO coming as well (maybe a Doublet version)?

[LewisM]

Well, the APM 150 doublet is made in China, so who knows. Could be.

I'd be tempted by it. Reports from the APM ones are fairly positive.

[Tropo-Bob]

... and just when I thought I had all the equipment that I wanted...

[glend]

Just spoke to Luke, he confirms it is a Doublet APO but cannot tell me what kind of glass but thinks its from Schott. Seems to be the big brother to the ED120 Black Diamond version. Definitely not in the Esprit line. He says the price will be around the $3000 mark, or just under.

Now by coincidence (?), Astronomics is releasing its 152mm Doublet APO in January and is accepting pre-orders. There is a thread running on a beta test on CN. The Astronomics 152mm Doublet APO is priced at $3999 USD, but it may have better Abbe numbers and build quality, too soon to tell.

Big difference between the $3000 AUD (landed and GST inc) and $3999 USD without delivery or import charges. I assume the Skywatcher would need a focuser upgrade, but not the Astronomic.

The APM 150 Doublet does look good, and its on sale right now for 2998 euro, or $4690 Aud (without shipping or import charges). Astronomics specs look very similiar but the $5260 AUD price give a big advantage to the APM sale price.

Its good to see more competition in this sector.

[MortonH]

Andrews' website now confirms the price as $2999. That's remarkably cheap if it's FPL-53. Makes me wonder if it's using FPL-51 instead.

[glend]

I will be surprised if its FPL-53.
The APM 152mm Doublet is using FPL-51 plus Lanthanum in its objective.

The APM 140 Doublet uses FPL-53, current price is circa $4200 AUD not including shipping and import charges.

[casstony]

The US Skywatcher rep who posts on CN has stated that he doesn't want to sell a scope which doesn't meet previous Skywatcher standards, so it might be fpl55 or 53. Time will tell.

[casstony]

On the Skywatcher Australia website you can download the 2018 catalogue with Australian pricing.
The SWBDED150, a larger version of the ED120, is listed at $2899 and the specs state fpl53 doublet.

http://skywatcheraustralia.com.au/wp-content/uploads/2017/11/SkyWatcher-Catalogue-compressed.pdf

[glend]

Well, there you go. That seems excellent value for the price, even if you have to replace the focuser.

[MortonH]

That's pretty amazing.

[Saturnine]

An 150mm ED for less than &3k, Skywatcher, please stop torturing me.
If it is the same glass as the APM / Lunt 150 ED, which is a good possibility, they have good reviews. So very, very tempting, but that's a lot of pension cheques.

[bigjoe]

Morton ..Hope it is FPL53 and good mating element (just as important )as this would be terrific for doubles and planetary Dsos and some imaging...I'll be in line if it is .already have 4ed and 6inch Fraunhofer doublet from SW..So it would be a big step up!

[bigjoe]

Thanks for the info Glen.. the APM was my first choice..maybe not now
Cheers bigjoe.

[bigjoe]

Tony.. sounds as if they dont want to make the mistakes they did years ago with their first lot of triplets
bigjoe.

[casstony]

I wonder if the mass producers use fpl55 to help keep costs down and just call it fpl53 for marketing purposes?

I note fpl55 has a higher melt frequency and is about 15% cheaper but has almost identical optical properties.

The lighter weight of an ED150 would be a big advantage over the Esprit, even if the Esprit is optically better.

[MortonH]

The Skywatcher guy on CN says the glass is not FPL-53:


"The glass they list is incorrect. We are using a proprietary glass combo to make these. Optics were designed by the same optical engineer that designed our Esprit triplets.

Now don’t let this whole glass thing scare you off. The color correction diagrams looks very good. It is my main concern to make sure the scope performs well and well corrected. I will know more once my samples arrived to me. "

[bigjoe]

FPL-53 is not just used to improve the chromatic aberration in an objective over that of FLP-51 , but really also to reduce the focal ratio requirements so a shorter F ratio can be used. F/8 Is quite ok and can get by with Fpl51 Fcd 1etc ...esp in triplets, as in Astrotech 115mm, a cracking scope! Its just FPL53 AND Flourite have more bragging rites.
bigjoe.

[casstony]

The 115mm triplet is a much smaller aperture and the extra element makes using fpl51 (or equivalent) easier. Apart from better possible colour correction with an fpl53 doublet the curves on the glass can be less steep and collimation/centering less critical, so there are good reasons to use fpl53/fpl55 in a doublet.

[skysurfer]

This one at TS? (https://www.teleskop-express.de/shop/product_info.php/language/en/info/p4880_Skywatcher-Esprit-150ED-Triplet-Super-Apo-Refraktor-Teleskop.html)
But it costs EUR 5200, a lot more, about A$7500. But this one is FPL-53.

[glend]

That Astrotech 115 is probably the same scope as the TS115, but they are Triplets, and using FPL-51 & Lanthanum elements in the objective, at f7, certainly does produce nice results. Those scopes are price leaders as well. The design trend seems to be, for Imaging Triplet f7 and faster, is to go to FPL-53 for at least one element, or to FPL-51 and Lanthanum combos. As you say, life gets easier at f8, but the Skywatcher 152mm is a Doublet, so the devil is in that objective details.

[bigjoe]

Keeping my fingers crossed then Glen..As a predominantly visual observer of Doubles,Planets and planetaries, a good doublet Apo would do me ..with good glass at F8..otherwise I may very well get a TS scope or APM..There all fabulous these days and a test report above .95 Strehl included by Marcus Ludes !
Cheers bigjoe

[Camelopardalis]

That US guy certainly has some bite :lol: I think he’s trying to breed some confidence into the brand, after all Skywatcher doesn’t have the brand presence and reputation that they do like in, say, Europe. I think it’s a bit of a reach to suggest that the US is “by far” their biggest market...maybe within the family of companies, but not SW specifically.

Skywatcher should certainly be able to produce the goods, the Esprit 150 is a fire cracker and grinding a f/8 shouldn’t present much of a challenge.

The price is mighty tempting...but I couldn’t bring myself to image at f/8, so someone here needs to buy one and experiment with what reducers work well ;)

[glend]

Had an email back from Luke (at Andrews), he says Tasco is trying to get objective details from Synta. He offered that the second element is likely not Lanthanum, given the local price point.
So what does that leave us? If you believe the Skywatcher guy on CN, its not FPL-53, and probably no Lanthanum either.
It will be interesting to see what eventually comes out on this scope.

[Tropo-Bob]

Astropetes is now advertising these for $2795.

The details of this scope will be interesting, however, I think some will be disappointed. The scope looks like the Black Diamond Achromat with an ED lens. It appears to lack many of the nice features normally associated with topline apochromatic telescopes. However, this is consistent with the Skywatcher ED range and for the price, it appears to be fantastic value for money.

I look forward to seeing user reviews rolling in next year.

[Camelopardalis]

So long as interested buyers understand that it’s the big daddy of the BD range, I don’t see a problem.

We do, after all, get what we pay for.

It’ll certainly be interesting to see how it develops, as a 6” ‘frac that’s well corrected for that money is certainly new territory. With a reducer and a little customisation (i.e. motorised focuser), it could make for a killer imaging scope for the price...

[Tinderboxsky]

If it is as well corrected as the ED120 then it has the potential to be an outstanding visual scope for the price too. I have a preference for well corrected doublets over triplets for visual. They have less glass, less weight and the very marginal improvement (for visual) is not worth the step up in price for a triplet.

[MortonH]

I was in Bintel today and they had hard copies of the Skywatcher 2018 catalogue. Nothing different from the PDF on the Skywatcher website but it was nice to see the same info, er... 'confirmed', in a proper glossy booklet.

[toc]

So what would the main advantages be of this scope over something like the Skywatcher MN190 scope?

[glend]

Well at present the ED150 is an unknown, other than rough specs like focal length. At 1200mm fl it is longer than the MN190, but optically slower at f8 verses f5. It is unclear if the ED150 will be a good imaging scope. It is a Doublet objective type refractor, the MN190 is a corrected, flat field, Mak-Newt. The MN190 works as both a visual and imaging scope right out of the box, you will need to buy bits to make the ED150 a good imager (assuming that optically it is well corrected), it would need a field flattener, or reducer corrector at the very least. They are very different optically, and budget wise.

[Kunama]

My guess would be that it will have glass from Chengdu. One thing for sure, it will be a BIG scope, given that the dew shield will not retract, expect something around 1350mm OTA length....

It is going to need a decent mount to control the moment arm of such length and to counter any breeze that should blow on it.

I think my money would be going to the APM 152F7.9 FPL51 doublet instead.

[LewisM]

And there is one of them in the trader right now - APM and Lunt ones are the same (and close by...Hmmmmm)

[glend]

And the second objective element is Lanthanum. Price has been dropped as well.

[FlashDrive]

+1 for me to ....:(

[Tropo-Bob]

I notice that that 150mm Achromat is not listed in the 2018 Skywatcher Catalogue. I assume the reality is that demand for the large achromat will fall away when the ED scope becomes available.

[bigjoe]

Thats the triplet Fpl53..This is going to be a doublet..which weve heard not much about ..what glass is going to be used at F8, needs to be better than Fpl51 or equivalent ..may be ok for visual though.
..someones got to Beta test it when it comes out
bigjoe.

[JimsShed]

We could speculate that it will have Hoya FCD100 like the new Saxons

http://www.astroshop.com.au/products/details.asp?id=MAS-045I7

[glend]

There is an interesting article here,

https://www.altairastro.com/ed-glass-types-used-in-altair-wave-series-refractors-and-how-this-affects-optical-performance..html

Comparing glass types and optical performance. It seems to peg the FCD100 Abbe number a little below FPL-53, but its much better than FPL-51.

As always the element it is partnered with, doublet or triplet design, etc all play a role in final performance. What can be acceptable visually may not be acceptable for imaging. Much of the discussion of the new crop of 150mm ED refractors on CN, is being led by guys that want it for visual use. It's going to be very hard to convince imagers that anything less than an equivalent of a FPL-53 triplet is going to be good enough for serious imaging.

I would find claims of FCD100 superiority to Flourite Abbe number to be pretty far fetched without diagrams to support that design.

[Tropo-Bob]

This new scope really had me thinking about the limits of refractors for us hobbyists. To increase in size again, above the 1200mm FL and large tube diameter for the 150mm scope, as well as the increasing difficulty in making quality lens for large sizes suggests some limits, or at least some rapidly shrinking diminishing returns on the money spent.

Pity, because I used the now defunct, Oddie telescope at Mt Strombo once, loved the experience and I still desire to have a really large refractor. However, at the larger sizes, other designs are more affordable, and even arguably better. So, I suspect, this is possibly as large as a reasonable quality, mass produced (and affordable to the most people) refractor will go.

[Wavytone]

Bob I too spent many Monday nights in the 70s with the Oddie, originally thanks to Ed Simmonds and before it was made accessible to others apart from the postgrad students at the observatory. While it was great for insane magnifications on the planets when seeing permitted it’s focal ratio made it pretty hopeless on DSOs. The little plate camera was ok but mainly for teaching the basics of plate photography for those who hadn’t learnt it in their undergrad course. I even used it as a guidescope with an 8” newtonian bolted on to take photos on several occasions.

But it really was a museum piece.

This may seem heretical to many here, but last year I put the refractor hype to the test with star tests on same objects through an assortment of three APOs 130-150mm side by side with a C6 a good 8” dob and my SW mak. The APOs included an AP Starfire 130 GT... nice scope but compared to the reflectors the only conclusion I came to is that the refractors are “try-hard wannabes” when it comes to real achromatism. As for resolution... sorry refractor guys, the 7” SW mak won every time and it matched them for contrast.

This was enough to wean me off refractors for good as the 7” mak won every comparison.

A 9” mak or SCT is about as big as I can lift and a 9” premium modern mak IMHO surpasses what the Oddie was able to do in every respect. A good 10” or 11” SCT ditto.

[raymo]

Well I don't find it heretical; Since getting my first proper scope [as opposed to a toy one] in 1952, I have either owned or used, scopes of many types
and sizes, and I have to say that I agree with Wavytone 100%. Oddly, I
have only ever had two Maks, a 6 and a 7, and both of them split
Antares more cleanly and aesthetically pleasingly than any other
amateur scope of similar, or even a little larger, size that I have ever used.
The SW 6" was especially good value for money.
raymo

[Tropo-Bob]

I read up on your rare 9" mak and it certainly sounds like a gem of a scope.
Very interesting remarks, that will have some of us refractor guys choking on our cornflakes. :)

[Tropo-Bob]

I have owned a lot of scopes, but never a Mak, so these are interesting remarks.

I find Antares easier to split with a SCT, so perhaps something to the central obstruction happening to make the split easier?

[glend]

Andrews is now advertising the Skywatcher ED150 will arrive shortly with a FPL51 element in the Doublet objective.

[glend]

Discounting already?
Astronomy Alive is advertising the as yet unseen Skywatcher ED150 for $2729 AUD. Obviously shipping charges will apply, but from where? The scope would likely be shipped directly from Tasco at Brookvale NSW to the buyer.
Andrews is still advertising the ED150 at $2899, plus shipping, again from Tasco.
Looks like a savings of $170 if you order through Astronomy Alive, assuming they honor that offered price.

[LewisM]

The Astronomy Alive discount is probably because he'll claim he was the optical designer for it :abduct:

[glend]

Ha ha ha, you make my laugh Lewis. I just got off the phone with him and he was trying to up-sell me on one of his designs.
BTW, he confirmed the $2729 price, and of course claims most inbound are already pre-sold.

[bigjoe]

Airy disk smaller in big SCT ..EASY split in very good conditions.

One good early morn , I split Antares cleanly with an ETX 125 , that I could not in a bigger cooled SCT..they get affected by seeing a bit more due to the big central obstrction in my experience .

Though if seeing is very good , they WILL perform to their theoretical limits, and outperform a smaller aperture..but not as often as in the Mak or refractor.

bigjoe.

[LewisM]

HIS designs - now you make ME laugh Glen :lol:

[AG Hybrid]

Interesting stuff.

To be fair Wavy. I've had a good look through your Mak. That thing is a god-damn unicorn being ridden by bigfoot. It's no wonder even the best refractors with smaller apertures cant compete.

[bigjoe]

Even though I no longer have a Maksutov the've all split just about any double I've thrown at them...even in average conditions..would I love another one ..YES..even bigger over around 250mm would be Ideal for me... to go with the 130mm triplet and others
.
bigjoe

[bigjoe]

Too true Adrian ..Wavys big Maksutovs..would surely be very hard, nie impossible for any good smaller refractor or SCT to beat on a lot of targets.

Even in good to average seeing , once cooled down.Central obstructions under 24% barely affect the image at the EP ..and so aperture RULES!...seen this many times.

bigjoe.

[bigjoe]

By the end of the month one of them could be offered as a TRIPLET in a DAIRY GRADE CELL ..you never know your luck with one of his designs .. FLOURITE ?. Hes UNIQUE I say.;)
bigjoe

[LewisM]

I have contacted MY dealer to see what price they will do one at.

I'd like one for visual.

[bigjoe]

These should be great for visual you'd imagine..what thev'e mated it with ..well find out soon enough.

That and nice polishing, and coatings weve come to expect from Synta, should make for a great visual scope.

With all the coming Planetary oppositions ..esp Mars, M22 and Saturn On April Fools Day and the next..don't anyone be an April Fool, and miss them.

bigjoe.

[LewisM]

The exceptional optics I expect for imaging is well covered by Tak with me, so this leaves visual, where a small difference in Strehl means stuff all considering the human eye cannot see the difference (unless the figure is horrid)

So, so long as the SW meets or exceeds 0.9 Strehl, I am fine with it.

I was considering a Mak, Mewlon or even a Dob for visual, but ruled all of them out for various reasons (cool down, dewing issues etc), so this leaves me the ED150 :)

If my dealer says circa $2800, I am in.

[LewisM]

I got VERY good news from my dealer, but he will update when these arrive in country. Same price (actually slightly better) as "elsewhere".

[bigjoe]

.

Cant wait till someone actually tests one..

I have a feeling it will be above .90 Strehl and be a surprise...theres no way Synta SW will make or release, with their vast experience and knowhow , anthing thats not at least very good to excellent with these APOs.

bigjoe.

[Tinderboxsky]

They will be a challenge to view on April Fools Day. I think they rise about 10.45pm on the 1st April. Best viewing will be in the morning of the 2nd, just before twilight kicks in.

[bigjoe]

All too true Steve ..those remarks were mostly intended as a Reminder ..a few hrs later will of course be ideal.

This is going to one of the best years in Astronomy , for a long time... and SW is finally coming out with a big 6 " Ed Apo that would be perfect for this.

bigjoe.

[Tropo-Bob]

Astro Petes has advertised $2795 for about a month now, so not a tough ask.

Me? I will consider it when U sell yours for a further discount in 2 or 3 months time. :D

[LewisM]

Got confirmation circa $2650

[Wavytone]

You should try again now that I've fixed the collimation. It was quite close but not quite perfect at 450X and I thought leave well enough alone. But last Saturday I broke out the screwdriver and tweaked it, ever so gently. All it took was barely crack 1 screw, perhaps 1/10th of a turn or less.

Now that it's spot on I can say a Strehl of 97% is quite something to behold, and I was quite surprised at just how much difference that tweak made at really high powers on close multiple stars and planets.

Something else also stood out looking at the moons of Jupiter and Saturn - even in poor to average seeing its quite easy to identify those that are moons and not stars. Jupiters moons are resolved nicely... Saturns are harder.

Compiling a list of close double stars to see how it fares near Dawes limit.

FWIW I have a nice 8" f/9 mirror with a fine figure in storage, never used.... I think that's going to be up for sale soon.

[Wavytone]

OK I give in. Finally. For the first time in... cripes... 30 years... this year I'll try taking some shots with a camera through the scope.

By the way Joe, if you have the place to put it there are some serious big maks going... https://www.astromart.com/classifieds/details.asp?classified_id=968866

... and more... it seems APM have sourced some large mak optical sets from LOMO again, 10" and larger.

I'll have to wait till retirement but by then I probably won't be able safely lift one larger than my current one.

[bigjoe]

Wavy...

Collimation...Thats actually a bigger problem than most realise with SCTs and even less frequently Maksutovs

One of the main reasons otherwise good SCTs get bad raps..usually the owners fault ..some are even sold way out of collimation to the unwary, only to be cursed and resold within months..

They all screem foul about the ordinary images, and thats one bad reputation they unfairly hold ..bad images that should not be in most cases...Ive had some really good ones...Collimation and cooling is a must otherwise they will perform poorly.

PS: Wonder if Synta SW or Celestron will ever release a big Maksutov over 200mm , they had one 305mm in testing ..what happened to that!

bigjoe

[AG Hybrid]

Next time we meet. Can you bring what ever tools you used? I'd like your help collimating my Mak. After opening it up multiple times for flocking the collimation is slightly out. At least according to star tests.

[glend]

Back on topic: the Skywatcher ED150.

As might have been mentioned previously, the APM 152mm Doublet, f7,9 happens to use FPL-51 and Lanthanum, which might be pretty close to the Skywatcher ED150 spec. The APM, and its Lunt, breathern, are pretty higjly regarded as a visual scopes. Could the APM have been the Skywatcher target. With Andrews now listing FPL-51 as one component, it is a possibility. Its (the ED150), affect on the APM price point, longer term, could be interesting.

[brian nordstrom]

:thumbsup: Yes as we all know , the mating element makes or breaks an objective and FPL51 and Lanthium are well regarded in this respect and with SW's track record ( ED80 -100 and 120 , yes I know these are SPL53 but not a Lanthium mating element ) I believe these should be a little better than the APM/Lunt 150mm APO's .

Computer mapping has come a long way in the 5 or so years since APM did the un-believable by allowing us with little money the chance to own a 6 inch APO .

Well done Sky Watcher :thumbsup::thumbsup::thumbsup: , I will be following these very closely ( along with plenty of others I am sure :D ) .

Go on Lewis be out beta tester here in Australia .;) . Go on !

Brian.

[LewisM]

Well, technically they aren't apochromats :P

I am seriously considering one.

[brian nordstrom]

:P Knew it ,, did not take long ,,,,, but yes they pass the APO spec by bringing 3 colours to a point that is perfect enough for visual , these were never designed for AP , thats why there are 80-100mm short f/l triplets and quads out there .

But never the less do a google on 'astro photography with an ED80' and you will see plenty of awesome shots taken with a ' Technically non APO ' scope but as said these were not designed for AP in mind , imagine the mount needed ,,, mmmm AP900 or 1200 ? perhaps ? .

Go for it Lewis ,,, ;) . get one .

Brian.

[LewisM]

For sure you can do AP with doublets, and some are better than others, but there is ALWAYS a slightly observable halo despite the best correction. A good triplet or quad on the other hand mitigates it almost entirely (notice I said GOOD - there are a few triplets out there not even as good as a good doublet!)

My BD150 is going to be a pure visual instrument. That's all I want it for. Unless I buy Steffen's Mak :drool:

[thebonz]

If these are what they are built up to be., I will have a severe case of TAKYPHALAXIS and put my FS128 in the museum for preservation and bring on the 6 incher

[LewisM]

Or sell me the 128 so you can afford the 150 :D (just after I sold the Tenba FS128 case of course)

[bigjoe]

Matthias Wirth scopes are beyond awesome and designed by Dr Phillip Keller...in Germany...Some of those LOMO Russian blanks are tens of thousands alone!

The prices are usually Astronomical to use a very worn out pun..but its the same performance as an 11 inch Apo that one offered in the Ad.

If I ever bought something like that....................."Im gunna need a bigger boat"! .....read that mount...some time off yet!

bigjoe

[Wavytone]

Lewis, No halos here, nada, zip, none :D

Last year I came to the conclusion that APO's are all wannabe's. Wannabe reflectors, that is.

Shocking, I know.

They can be very good, I agree, but none are perfectly achromatic across the whole spectrum in the way that a good reflector or catadioptric is.

FWIW there is an interesting rumour that Questar is considering making a Q5. That should be a really, really interesting scope, and if it came down to a choice of that vs a Takahashi I'd take the Q5, no question.

[thebonz]

It as depends on your point of view of course. The doublet refractor will give wider field views that settle very quickly where as the mac will be a longer focal length narrower field of view. Horses for courses of course.

[Wavytone]

Adrian did flocking make much difference to your scope ? For example, contrast when observing a star near the lunar limb, where stray light is very difficult. Mine is good at that test, but am scratching my head as to whether flocking would make any difference.

Reason I ask is that I'm preparing to pull my OTA apart later this year for several mechanical mods, and am thinking about whether to flock the inside of the OTA as well.

FWIW Steffen has just listed his Intes 6" mak. The humidity must have driven him crazy.

[LewisM]

We shall agree to disagree :)

More pros with a refractor IMHO than a Mak.

[glend]

Mak, Mak, Mak, get over it. Questar's are not exactly cost effective regardless of size. An 8" Edge HD makes more sense, and i have one. However, i cannot denigh the attraction of a good long refractor at a reasonable price. I would like to put the Skywatcher ED150 f8 up against my iStar 127mm f12 R30 Anastigmatic, Strehl of 0,93. :eyepop:

[LewisM]

Questars are not as good as their fable either. Not sure anyone was talking Questar here anyway?

And Matt no longer has his Mak either - the continual dew problems and protracted cool-down (plus the desire for a Bino-scope Tak) saw him sell that. I experienced the same issues with the Maks I have owned (2).

[AG Hybrid]

Like all telescope designs, be it refractors, reflectors and composites. You can't gain contrast over the original intended design. But, through manufacture process and materials used it can be lost due to light scatter and what not. Flocking helps with removing the doubt of "Am I getting the best performance?". In my case, the flocking reduced stray light illuminating my inner tube as my backyard is rather well lit through no fault of my own.
The long focal length and optical design already lends to excellent contrast.
Flocking made the biggest difference in my Skywatcher strut dob.

[glend]

Well things certainly change quickly. According to Luke (at Andrews), he has just received this information on the ETA.

Tasco are now expecting them to ship in late April and are hoping to receive them in early May.
He was not sure where the late Jan/early Feb timeline came from as Tasco are now saying that*the factory is apparently not commencing mass production until around the end of Feb.

This information lines up with what Kevin from Skywatcher USA said (from China) about them being doubtful for NEAF.

There you go.