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Starwave 102ED f11 (yes, ED)

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#51 Eric H

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Posted 11 January 2019 - 10:36 PM

Can't wait to hear some reports!



#52 Jon Isaacs

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Posted 11 January 2019 - 10:45 PM

With a color blur of less than 1, it is definitely an APO.  This scope must be using something like FPL-53 to achieve that value of f/df.  The SW 100 Ed uses FPL-53 and has excellent color correction at f/9.

 

 

I agree that it would have to be something similar to FPL-53 to have that kind of correction.  This scope is not a great deal more than the AT-102ED and I believe is manufactured by Kunming United. It is around $600 and does not have a sliding dew shield. I just don't see a FPL-53 class objective in a Kunming or Long Preng 4 inch scope for less than around $1000.  

 

It's all speculation until someone has one.   

 

Jon


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#53 jrbarnett

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Posted 11 January 2019 - 11:03 PM

No need for that. It's white and has a sliding dew cap, with a pretty logo on it. What more do you need? wink.gif

 

 

Clear skies!
Thomas, Denmark

Thomas, you always were a sucker for a pretty...er...dew shade.  I too have a fondness for properly long, white dew shades.

 

The best dew shade I have is pictured below.  2.5x the aperture in length.

 

Best,

 

Jim

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#54 jrbarnett

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Posted 11 January 2019 - 11:12 PM

I agree that it would have to be something similar to FPL-53 to have that kind of correction.  This scope is not a great deal more than the AT-102ED and I believe is manufactured by Kunming United. It is around $600 and does not have a sliding dew shield. I just don't see a FPL-53 class objective in a Kunming or Long Preng 4 inch scope for less than around $1000.  

 

It's all speculation until someone has one.   

 

Jon

Why not?  There are Synta 4" FPL-53 doublets for much less than $1000.

 

https://www.bhphotov...ft=BI:514&smp=Y

 

And now Hoya has a cheaper FPL-53 competitor, FCD-100.  It is used on ES triplets and now is showing up in cheaper binoculars.

 

Also Kunming (who clearly makes this scope) will do builds with either HFK-61 or FPL-53.  TS offers a Kunming 130ED FPL-53 triplet for a price not much higher than other dealers' Kunming 130ED triplets using HFK-61.

 

And there are many grades of optical glass.  Maybe the cheaper scopes are using high occlusion ED blanks rejected by pickier optics manufacturers.

 

Best,

 

Jim


Edited by jrbarnett, 11 January 2019 - 11:33 PM.

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#55 jay.i

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Posted 12 January 2019 - 01:20 AM

Why not?  There are Synta 4" FPL-53 doublets for much less than $1000.

 

https://www.bhphotov...ft=BI:514&smp=Y

 

And now Hoya has a cheaper FPL-53 competitor, FCD-100.  It is used on ES triplets and now is showing up in cheaper binoculars.

 

Also Kunming (who clearly makes this scope) will do builds with either HFK-61 or FPL-53.  TS offers a Kunming 130ED FPL-53 triplet for a price not much higher than other dealers' Kunming 130ED triplets using HFK-61.

 

And there are many grades of optical glass.  Maybe the cheaper scopes are using high occlusion ED blanks rejected by pickier optics manufacturers.

 

Best,

 

Jim

The new A-P Stowaway uses FCD-100 as well. It would be cool to see an aggressively priced semi-fast doublet with it. Maybe 130mm f/7? The SV125-A uses FCD-100 now too and is 125mm at f/7.8. I don't know if it's possible to go wider and faster and still maintain good correction. Hopefully it is! Who knows what manufacturers will do with FCD-100 in the next year or two, my guess is good things!



#56 Sasa

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Posted 12 January 2019 - 06:38 AM

I agree that it would have to be something similar to FPL-53 to have that kind of correction. This scope is not a great deal more than the AT-102ED and I believe is manufactured by Kunming United. It is around $600 and does not have a sliding dew shield. I just don't see a FPL-53 class objective in a Kunming or Long Preng 4 inch scope for less than around $1000.

It's all speculation until someone has one.

Jon

My code gives me about 30 suitable glasses that produce together with S-FPL51 color defocus 1/10000 or better (C,F lines with respect to e). Majority of them are suitable to design Fraunhofer doublet 102mm at f/11. Some of the glasses are even cheap, like S-BSM15 (f/df~10000), K10 (f/df~10000), N-K5 (f/df=14000), K7 (f/df=21000). I like the combination with K10, curvatures are reasonably mild (inner surfaces have about 232mm radius). The lens has very good control over spherochromacity (the worse is C-line with strehl 0.98). My code gives an estimate of polystrehl 0.97 at best polystrehl focus. If the lens is focused in e-line, you still have strehl 0.82 at F-line and 0.89 at C-line. If you don't want good performance in violet g-line for astroimaging, there is no need to use S-FPL53 for visual use at f/11.

Edited by Sasa, 12 January 2019 - 09:26 AM.

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#57 Astrojensen

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Posted 12 January 2019 - 07:09 AM

With potential numbers like these, I am getting a bit excited. 

 

 

Clear skies!
Thomas, Denmark


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#58 dscarpa

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Posted 12 January 2019 - 04:22 PM

 Was leaning toward  getting a 90 Coronado 3 but that scope with a 90 Coronado etalon and BF on now empty Unistar-AP tripod would be sweet. Longer FL for less seeing sensitive scope is a big plus for HA.  David   


Edited by dscarpa, 12 January 2019 - 04:25 PM.


#59 HARRISON SCOPES

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Posted 12 January 2019 - 04:37 PM

I'll see if I can star test one early next week if the January cloud blanket gives a break.
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#60 aa6ww

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Posted 14 January 2019 - 01:13 AM

  I dont think a GP mount is enough mount to handle the length optical tube without considerable setting time, something I cant deal with at any level.

  I have a Vixen GP DX with Hal 110 legs and have tried my friends Astrotelescope 102 F/11 on it and though it looks very cool, the settling time during focusing was horrible. This was with the legs full extended in grass but without my accessory tray attached, which does add to the stability somewhat.

  My 120ED Skywatcher is considerably more stable on the same mount, and shows no settling time at the eyepiece. 

We tried Mars at almost 250x and the focuing was completely unacceptable, having to let go of the focuser and let the scope settle down before trying to observe the polarcaps. Lower Magnifications where most of our observing is done at anyways, probably would be acceptable.

  In my situation because I use my lightweight mount for my smaller refractors, I would consider a Hargreaves Strut for added stability to tame down the dampening on such a long tube scope on a lightweight mount.

 I do like the 102ED F/11 but it wouldn't work for me because more than likely I would have to use my G11 mount to stabilize the scope. If I was going through all the set up time on my G11, Id just rather use my 152ED refractor.

   

 ...Ralph

   

 

 

Hi Thomas,

that sounds really interesting. I hope that you get  a good refractor. I am curious how good this refractor is and what you tell us.

A normal Vixen GP, Celestron ADM or similar should be fine. You probably don't need a Vixen Saturn. I have the achromat version with 4" f/11 and for me it works ond a ADM fine.

Clear skies,

  Roland


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#61 Jon Isaacs

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Posted 14 January 2019 - 06:06 AM

Why not?  There are Synta 4" FPL-53 doublets for much less than $1000.

 

This is obviously not a Synta scope and Synta makes other compromises. 4 inch Kunming United/Long Perng doublets that use FPL-53 cost at least $1000. You don't get the nice build with the nice paint, machined focuser, machined rings and sliding dewshield AND FPL-53/FCD-100 for under $700 including VAT.  This scope would be $600 in the US. That's what a AT-102ED costs with the HK-61 objective. 

 

And APM is selling the Evostar ED100 for over a $1000.., 

 

 https://www.apm-tele...o-refractor-ota

 

My code gives me about 30 suitable glasses that produce together with S-FPL51 color defocus 1/10000 or better (C,F lines with respect to e).

 

I think anyone who has owned a Kunming United or Long Perng FPL-51 or HK-61 doublet is aware that their color correction is not that good. 

 

Jon 



#62 Astrojensen

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Posted 14 January 2019 - 11:21 AM

I think anyone who has owned a Kunming United or Long Perng FPL-51 or HK-61 doublet is aware that their color correction is not that good. 

 

Jon 

Yes, but those are f/7-ish scopes, not f/11 ones. There is a tremendous difference between f/7 and f/11 in color correction with the same glass types. Just think of the difference between a typical f/7 achromat and an f/11 achromat. 

 

But all this is still speculation, until mine arrives and I can get it under the stars.

 

 

Clear skies!
Thomas, Denmark


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#63 daquad

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Posted 14 January 2019 - 01:31 PM

  I dont think a GP mount is enough mount to handle the length optical tube without considerable setting time, something I cant deal with at any level.

  I have a Vixen GP DX with Hal 110 legs and have tried my friends Astrotelescope 102 F/11 on it and though it looks very cool, the settling time during focusing was horrible. This was with the legs full extended in grass but without my accessory tray attached, which does add to the stability somewhat.

  My 120ED Skywatcher is considerably more stable on the same mount, and shows no settling time at the eyepiece. 

We tried Mars at almost 250x and the focuing was completely unacceptable, having to let go of the focuser and let the scope settle down before trying to observe the polarcaps. Lower Magnifications where most of our observing is done at anyways, probably would be acceptable.

  In my situation because I use my lightweight mount for my smaller refractors, I would consider a Hargreaves Strut for added stability to tame down the dampening on such a long tube scope on a lightweight mount.

 I do like the 102ED F/11 but it wouldn't work for me because more than likely I would have to use my G11 mount to stabilize the scope. If I was going through all the set up time on my G11, Id just rather use my 152ED refractor.

   

 ...Ralph

Ralph, my experience with the Astrotelescope 102 f/11 Achromat on a Vixen GP Dx was the same as yours.  I always had to use it on my Losmandy GM-100.

 

Dom Q.

 

DSCN1640.jpg


Edited by daquad, 14 January 2019 - 01:32 PM.

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#64 daquad

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Posted 14 January 2019 - 02:16 PM

This is obviously not a Synta scope and Synta makes other compromises. 4 inch Kunming United/Long Perng doublets that use FPL-53 cost at least $1000. You don't get the nice build with the nice paint, machined focuser, machined rings and sliding dewshield AND FPL-53/FCD-100 for under $700 including VAT.  This scope would be $600 in the US. That's what a AT-102ED costs with the HK-61 objective. 

 

And APM is selling the Evostar ED100 for over a $1000.., 

 

 https://www.apm-tele...o-refractor-ota

 

I think anyone who has owned a Kunming United or Long Perng FPL-51 or HK-61 doublet is aware that their color correction is not that good. 

 

Jon 

Jon, I'm not sure what you mean by "not that good."  Those who post on the AT102 ED thread have nothing but good things to say about that scope, including its color correction, which, by the numbers, is better than a 4" f/15 achromat, which most would say is good.  We're talking visual, of course.

 

Dom Q.



#65 mikeDnight

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Posted 14 January 2019 - 04:00 PM

I've never really understood the seemingly single minded consideration of colour correction, when as Thomas has already mentioned, there are other more important factors to consider such as spherical abberation, smoothness of figure etc. I have little doubt this new F11  ed apo will have very good colour correction. And a sobering thought always sticks in my mind from about ten years ago, when my friends 102mm Vixen F6.5 ED gave a far superior and more detailed view of Saturn's ring system than my NP101, which had superior colour correction and cost around three times the price. There are far more important factors at play in a good telescope than colour correction! I have no idea what glass types Vixen used in their F6.5 ED's but the level of CA was certainly not objectionable, even on the brightest objects. With newer ED glasses and a good figure, I'd be fairly certain this new scope will pack a serious punch.


Edited by mikeDnight, 14 January 2019 - 04:01 PM.

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#66 John Huntley

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Posted 14 January 2019 - 05:28 PM

Though never stated or confirmed by Vixen I believe the ED element in the ED102SS is FPL-51 Mike. Fine scope, I agree smile.gif


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#67 Niklo

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Posted 15 January 2019 - 05:03 AM

Ralph, my experience with the Astrotelescope 102 f/11 Achromat on a Vixen GP Dx was the same as yours.  I always had to use it on my Losmandy GM-100.

 

Dom Q.

 

attachicon.gif DSCN1640.jpg

Hi Dom,

I used my 102/1100 on a Celestron ADM and a Vixen GPD2 and had no problem. On your photo the upper part of the 102/1100 is very long and so the lever arm is very long. As far as I rember I used the telescope more centered so that could be one reason of our different experience. By the way on both mounts I use my 6" f/8 Orion UK newton and a modified Tal2 newton without problems, too. I am fine with these mounts for all of my telescopes except the 4" f/15 which is too long and too heavy. That's how I see it but other people see it differently. smile.gif

My estimation for visual use is quite similar to the mount table:

http://www.deepsky-b...biTEL_Monti.htm

 

What is very important is a solid tripod below the mount.

 

For me it would be overkill to buy and use a Saturn mount but it looks nice and if it's already in house and no hassle to carry the mount and tripod around ... why not using it for lightweight telescopes, too.

The same is possible for the EQ6 and a 114/900 newton. Completely rock solid. smile.gif

Clear skies,

  Roland


Edited by Niklo, 15 January 2019 - 05:05 AM.


#68 Terra Nova

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Posted 15 January 2019 - 10:44 AM

Congratulations Thomas. In terms of appearance, build, and dimensions it looks pretty identical to the Astro Telescopes 102mm F11 achromatic refractor I used to have and I was very happy with that scope (other than its size and weight which was a bit more than I liked, but that is just me and my physical requirements). Optically the scope was as good as the two 4” F15 scopes I used to have (Unitron and Edmund). Kunming did a very nice job with it and I can see no reason why your new scope won’t be even better! I’ll bet you will be quite satisfied. waytogo.gif


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#69 daquad

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Posted 15 January 2019 - 02:10 PM

Hi Dom,

I used my 102/1100 on a Celestron ADM and a Vixen GPD2 and had no problem. On your photo the upper part of the 102/1100 is very long and so the lever arm is very long. As far as I rember I used the telescope more centered so that could be one reason of our different experience. By the way on both mounts I use my 6" f/8 Orion UK newton and a modified Tal2 newton without problems, too. I am fine with these mounts for all of my telescopes except the 4" f/15 which is too long and too heavy. That's how I see it but other people see it differently. smile.gif

My estimation for visual use is quite similar to the mount table:

http://www.deepsky-b...biTEL_Monti.htm

 

What is very important is a solid tripod below the mount.

 

For me it would be overkill to buy and use a Saturn mount but it looks nice and if it's already in house and no hassle to carry the mount and tripod around ... why not using it for lightweight telescopes, too.

The same is possible for the EQ6 and a 114/900 newton. Completely rock solid. smile.gif

Clear skies,

  Roland

Hi Niklo, with the GM-100 I can use the mount with the tangent arm dec drive toward the focuser end, as my photo shows, or the objective end.  If I used it toward the objective end, the tube would balance more toward the center, but the eyepiece will be lower.  With it mounted as shown in the picture, I got a more comfortable eyepiece height.  Either way the GM-100, nearly 28 years old now, carried it with no shake whatsoever even while I was focusing.   

 

The Vixen GP DX had aluminum legs, so as you pointed out maybe that was the weak link.  



#70 Astrojensen

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Posted 15 January 2019 - 02:13 PM

It's here. Short, first impressions:

 

No damage during shipping. The box is decent, but only single layer. The scope is held with foam blocks inside the box. 

 

The tube looks very nice and has a nice heft to it. Overall build quality is very, very nice for the price. The focuser is smooth and solid, but the microfocuser gearing is not completely smooth and has some tight spots, which gives it an odd feel, when you turn it. It doesn't appear to affect focusing, though, but we'll see when we're out under the stars.

 

The removable section was clearly not assembled correctly and I had to dis- and reassemble it, to find the optimum position. Now it appears to be fine. The three small screws that hold the threaded insert are clearly too small and I'll have to replace them. They're hex screws and one was already slightly damaged, when I received the scope. I could still remove it and reattach it, but I can't tighten it like the others. 

 

The threads that hold the focuser and the removable tube section are quite tight and I needed to lubricate them with a bit of silicone lube, to get rid of the insanely loud screeching noise they made, when I turned them. It'll get better with use, I suppose. 

 

The dew shield is quite long, very nice and slides back and forth with just the right amount of friction. The dust cap is metal, feels very solid and sits quite snuggly and securely over the dew shield. 

 

The paint is flawless, both in- and outside. Inside is very nicely baffled and blackened. The focuser has a truckload of baffles. The main tube has several. Even the dew cap has one, right at the front. The outside paint has a nice, slightly rough texture to it, making handling the scope much safer and much less stressfull, since it never slips in your hands.

 

The tube rings are extremely nice and very solid. Turning the scope in the rings can be quite difficult, due to the rough texture. 

 

I haven't tested the optics yet, but the coatings on the objective are insanely nice. The glass is completely invisible, unless strongly illuminated. It does NOT have that strong, greenish cast you see on some cheaper refractors. 

 

More to come, as well as pictures. 

 

 

Clear skies!
Thomas, Denmark 


Edited by Astrojensen, 15 January 2019 - 02:18 PM.

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#71 Sasa

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Posted 15 January 2019 - 03:17 PM

Congratulation Thomas. Eagerly waiting the images and your reports!

#72 Riccardo_italy

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Posted 15 January 2019 - 03:54 PM

Congrats Thomas, really looking forward for pics and first light impressions!



#73 starcanoe

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Posted 15 January 2019 - 04:11 PM

Wow....certainly sounds nice !



#74 Astrojensen

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Posted 15 January 2019 - 04:31 PM

Okay, believe it or not, but I just had a first light of sorts. It was 99% cloudy (or more), but I could see the Moon, as well as some stars, through an occasional sucker hole for a few, brief moments. It was also very windy and the seeing was mostly pretty horrible. The scope was mounted on my Zeiss 1b mount, which felt like an almost perfect combination. I used a Baader/Zeiss T2 prism diagonal and my ES eyepieces. 

 

I quickly aimed at the Moon, using my 11mm ES82 (102x). Despite just a few minutes of cooldown, the image snapped into focus. There was no visual false color whatsoever that I could see. I repeatedly studied the image at 168x (6.7mm ES82) and saw no false color at all. The limb of the Moon was razor sharp, like cut with an exacto knife. Contrast was superb, even through thin clouds and with little cooldown time. Even out of focus revealed very, very little false color. I couldn't do a proper star test, but I managed to find Procyon and rack it out of focus, so I could judge the collimation, which appeared to be spot on. I could see that the upper end of the defocused disk was fuzzy and wavering, a clear sign of heat plumes in the scope. 

 

In short: The optics on this scope appear to be no joke, especially the color correction. Can't give an assessment of the spherical correction yet, but it does appear to be at least very decent. A really clear night with better seeing should tell me more. 

 

 

Clear skies!
Thomas, Denmark 

 

PS: Pictures will have to wait until tomorrow, as it's getting pretty late here and I'll have to head for bed now.


Edited by Astrojensen, 15 January 2019 - 04:34 PM.

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#75 Jond105

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Posted 15 January 2019 - 04:54 PM

Congrats on the new scope, very interesting an F/11 ED. Can't wait to hear more observing reports. I have no intentions to get one, but I love to read about scopes I'll never get.
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