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View Full Version here: : Skywatcher ED150/1200 APO. Is this real or fake news?


glend
28-11-2017, 07:50 AM
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
28-11-2017, 08:26 AM
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
28-11-2017, 08:34 AM
... and just when I thought I had all the equipment that I wanted...

glend
28-11-2017, 08:40 AM
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
28-11-2017, 08:56 AM
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
28-11-2017, 09:00 AM
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
28-11-2017, 09:15 AM
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
28-11-2017, 09:33 AM
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
28-11-2017, 09:42 AM
Well, there you go. That seems excellent value for the price, even if you have to replace the focuser.

MortonH
28-11-2017, 10:09 AM
That's pretty amazing.

Saturnine
28-11-2017, 10:55 AM
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
28-11-2017, 11:10 AM
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
28-11-2017, 11:14 AM
Thanks for the info Glen.. the APM was my first choice..maybe not now
Cheers bigjoe.

bigjoe
28-11-2017, 11:17 AM
Tony.. sounds as if they dont want to make the mistakes they did years ago with their first lot of triplets
bigjoe.

casstony
28-11-2017, 11:38 AM
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
28-11-2017, 01:55 PM
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
28-11-2017, 02:01 PM
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
28-11-2017, 03:11 PM
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
29-11-2017, 06:45 AM
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
29-11-2017, 07:20 AM
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
29-11-2017, 11:35 AM
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
30-11-2017, 09:38 AM
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
30-11-2017, 09:59 AM
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
03-12-2017, 08:50 AM
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
03-12-2017, 11:19 AM
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
03-12-2017, 02:06 PM
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
03-12-2017, 03:05 PM
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
03-12-2017, 10:53 PM
So what would the main advantages be of this scope over something like the Skywatcher MN190 scope?

glend
04-12-2017, 06:01 AM
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
04-12-2017, 06:35 AM
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
04-12-2017, 10:20 AM
And there is one of them in the trader right now - APM and Lunt ones are the same (and close by...Hmmmmm)

glend
04-12-2017, 10:57 AM
And the second objective element is Lanthanum. Price has been dropped as well.

FlashDrive
04-12-2017, 11:10 AM
+1 for me to ....:(

Tropo-Bob
08-12-2017, 10:20 AM
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
10-12-2017, 11:59 AM
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
19-12-2017, 06:42 PM
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
19-12-2017, 07:18 PM
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
06-01-2018, 09:54 AM
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
06-01-2018, 07:26 PM
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
06-01-2018, 10:05 PM
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
07-01-2018, 09:55 AM
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
07-01-2018, 10:00 AM
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
21-01-2018, 04:57 AM
Andrews is now advertising the Skywatcher ED150 will arrive shortly with a FPL51 element in the Doublet objective.