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Stellarvue SVX127D thoughts?

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#1 soulprophet

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Posted 02 January 2021 - 06:30 PM

Thinking of picking one of these up. The only other telescope I've ever really used is my Stellarvue 90mm fluorite triplet that I really enjoy. This will be for visual use only. Is it a nice jump from 90mm? I was thinking of their SVX130....but this is half the cost. 


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#2 scadvice

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Posted 02 January 2021 - 06:51 PM

I have the SVA130T ( One of the last 'A' versions but with a Strehl of .992). They are heavy in the front with all that glass! However, amazing views.  There is a new upcoming Doublet that are F/8 so if that works something to consider. I'd give them a call and see what they have on the shelf or coming up. I don't regret buying mine.


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#3 junomike

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Posted 02 January 2021 - 06:55 PM

Thinking of picking one of these up. The only other telescope I've ever really used is my Stellarvue 90mm fluorite triplet that I really enjoy. This will be for visual use only. Is it a nice jump from 90mm? I was thinking of their SVX130....but this is half the cost. 

I think it will be fine for visual but just remember it won't be the SVX130 at "half the cost" either


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#4 Heywood

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Posted 02 January 2021 - 07:13 PM

Thinking of picking one of these up. The only other telescope I've ever really used is my Stellarvue 90mm fluorite triplet that I really enjoy. This will be for visual use only. Is it a nice jump from 90mm? I was thinking of their SVX130....but this is half the cost. 

 

It would help a lot if you could tell us about the SVX127D.  It doesn't appear on the Stellarvue website, and I, for one, have never heard of it.  Is it a doublet?  Triplet?  Focal ratio?  Price?  Availability?

 

Thank you.



#5 JumboFlex

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Posted 02 January 2021 - 07:15 PM

I went from 100 to 140mm, it was an noted improvement in light grasp and resolution. Not revelatory but it could be appreciated pretty easily. Both scopes were on par from an optical quality standpoint (NP101 to TEC140). Other optical differences will be dependent upon the type of refractor, focal ratio...

 

Obviously the bigger you can go the better but that's also about the sweet spot before weight and size become an issue; however, if you are permanently or semi-permanently mounting than thats not as much of a concern. 



#6 soulprophet

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Posted 02 January 2021 - 07:42 PM

It would help a lot if you could tell us about the SVX127D. It doesn't appear on the Stellarvue website, and I, for one, have never heard of it. Is it a doublet? Triplet? Focal ratio? Price? Availability?

Thank you.


I saw it in an email from them. Doublet, F8, $2495, pre-order. It might not be a SVX130, but a doublet at F8 should be a pretty nice view.
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#7 Brollen

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Posted 02 January 2021 - 07:51 PM

It would help a lot if you could tell us about the SVX127D.  It doesn't appear on the Stellarvue website, and I, for one, have never heard of it.  Is it a doublet?  Triplet?  Focal ratio?  Price?  Availability?

 

Thank you.

I received notification on this new scope and other models via email - I am on a distro list for scope announcements, etc. I own an excellent SVR90T and have had it serviced at Stellarvue. This has lead to interest and conversations with Stellarvue folks about some of their newer offerings.

 

Per the email, the SVX127D is a very high Strehl f/8 doublet at an introductory price of $2495 ... with more details to be announced! Best to reach out directly to Stellarvue if interested or with any questions.

 

I for one, am very excited about their announced SVX102ED and have queued up for one. 

 

Clear skies!


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#8 Jeff Bennett

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Posted 02 January 2021 - 08:05 PM

It would help a lot if you could tell us about the SVX127D.  It doesn't appear on the Stellarvue website, and I, for one, have never heard of it.  Is it a doublet?  Triplet?  Focal ratio?  Price?  Availability?

 

Thank you.

I learned about this offering through an email from SV as well, but I was not surprised to see the announcement.  If you look at the Certified Pre-owned section of the SV website you will see the SVX125D, which is a scope that SV offered a year or two back in pretty limited quantities.  When the CPO model was listed a few months back I jumped on it and have had it out a number of times.  It has been a great scope with both an excellent focuser and very nice optics as well.  It goes a good bit deeper than my 92mm Stowaway, and it is lighter and a little easier to handle than my TEC140.

 

I suspect that the SVX127D is a slightly tweaked version (by 2mm, and addition of a 3-inch focuser as compared to a 2.5 inch version, who knows what else) of what I got.  I have seen a couple other SVX125Ds for sale on the used market in the past six months or so.  The SVX125D uses FCD100 glass along with a Lanthanum element, and at 975mm focal length is F7.8.

 

I will be very interested to see how long SV can stick with the $2495 price, including the case at least initially.  I would consider this a bargain given the promise of very well figured optics, particularly for visual use.


Edited by Jeff Bennett, 02 January 2021 - 08:07 PM.

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#9 soulprophet

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Posted 02 January 2021 - 08:08 PM

Obviously the bigger you can go the better but that's also about the sweet spot before weight and size become an issue; however, if you are permanently or semi-permanently mounting than thats not as much of a concern.


That’s what I’ve read about 127/130, sweet spot. I’m in the service so I move ever couple years or so, one day perhaps a forever home! I have looked through a 6 inch scope (I recall) and that was a monster.
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#10 Ennis

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Posted 02 January 2021 - 08:23 PM

This may be a dumb question, but would the image through an SVX 127mm doublet with 0.99 Strehl be essentially the same as the image through an SVX 130mm triplet with 0.99 Strehl?  If not, how would they differ?

#11 junomike

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Posted 02 January 2021 - 10:02 PM

This may be a dumb question, but would the image through an SVX 127mm doublet with 0.99 Strehl be essentially the same as the image through an SVX 130mm triplet with 0.99 Strehl?  If not, how would they differ?  

Tough call as it would depend if both used similar glass and F/L's.   I'd suspect the Triplet would be better for CA/Color correction however anything's possible.



#12 Spikey131

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Posted 02 January 2021 - 11:21 PM

This may be a dumb question, but would the image through an SVX 127mm doublet with 0.99 Strehl be essentially the same as the image through an SVX 130mm triplet with 0.99 Strehl?  If not, how would they differ?  

We will know when they leave the land of unicorns and someone points one up at the sky.

 

’Til then, we will all enjoy months of speculation.popcorn.gif popcorn.gif


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#13 121601

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Posted 02 January 2021 - 11:45 PM

This may be a dumb question, but would the image through an SVX 127mm doublet with 0.99 Strehl be essentially the same as the image through an SVX 130mm triplet with 0.99 Strehl?  If not, how would they differ?  

Perhaps the longer focal length may deliver identical performance but with less expensive glass.

 

I also checked my old notes. These may possibly be revised product (see:  www.cloudynights.com/topic/673667-stellarvue-drops-svx125d-again,

www.skiesunlimited.com/stellarvue-sv125-access.html,   f/7.8 @ $1995.00)

 

"...New SVX doublet! Using what we’ve learned hand figuring, we applied the same processes to the Access 125 mm doublets. We are proud to announce a high Strehl version, the SVX125D. These instruments are hand figured to .98 - .996 Strehl with low spherical error. The objective contains an apochromatic doublet using a combination of Hoya FCD100 and Lanthanum which will keep your image contrast high, and since every lens is aligned before ... you’ll be getting color free visual performance, but without the higher price...(SV Newsletter, May, 2019)."

 

There appears to be an earlier "STV-SVX125D" version ($2,595.00) as well:

astromart.com/classifieds/astromart-classifieds/telescope-refractor/show/stellarvue-access-125-apo-doublet-premium-hand-tuned-zygo-tested-at-sv

"The optics used in this model is FPL53 and Lanthanum glass to yield excellent color correction. The newer ones used FCD100 and Lanthanum.

(interferometry report attached)." 

 

For these 2 examples,  the PV (0 .134), RMS (0.012) and Strehl 0.994) specs. for the Hoya version (SV sale webpage) are numerically better than FPL53 version.   CS

Attached Files


Edited by 121601, 03 January 2021 - 03:44 AM.


#14 dhferguson

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Posted 03 January 2021 - 12:45 AM

Cheers,

 

If the SVX125D is "better" than my SVA125, it will be a truly exceptional visual-use refractor. I purchased my very similar (both are f/7.75 ED doublets) "Access" Chinese-made but Stellarvue-vetted telescope at the closeout sale of August, 2019. Since then, I have used it extensively and've enjoyed every minute.

 

Visual (fifty years of experience here):

Mine star tests to Strehl => 0.98 using a (teal-colored) narrowband Lumicon G3 OIII filter. How much better? I don't know: the star test becomes ambiguous and hard to interpret at higher Strehl. With broadband, the star test is a bit fuzzy in and out of focus, however, which is to be expected of any ED doublet. That said, there is zero, and I mean ZERO longitudinal color visible on the toughest of test targets: Vega, Venus, the lunar limb, and Betelgeuse for example. I don't know whether my telescope uses FCD-100 or FPL-53 glass; whichever, because they are essentially identical glasses from two different manufacturers. What does this mean for visual observing? That star images in good seeing exhibit perfect diffraction images: rings w/black in-between. Epsilon Lyrae is a breeze. Tighter doubles actually show the Airy disks touching or even merging. Jupiter's Galilean moons are crisp disks (unlike in my Edge 8" HD SCT). Moving to slightly larger angular scales but lower contrast, I would say, for example, that the detail on Jupiter's disk visible in the SVA125 is ever-so-slightly better than in the Edge 8" HD, and I have compared the two extensively. What more can I say about the high visual quality?

 

AP (former professional astronomer but beginning amateur AP'er):

My ED doublet is very usable but there are two compromises. The first has to do with equipment: SV only offered a matched field flattener and not a flattener/reducer for my scope. I purchased and like it ... but ... Vic, can you recommend a flattener/reducer for a not-too-dramatic focal reduction too, something like f/6.5? Incidentally, the aforementioned flattener is sized to be suitable for full-frame imaging  and yields point-like, and I mean POINT-LIKE images at all corners on my APS-C sensor. The second issue, as might be expected, is "blue bloat" of certain stars. I use an Astronomik L3 UV/IR blocking filter (the most restrictive of the three) and this helps some. Using this filter, bloat is only hugely apparent on really bright, blue stars: the Pleiades and Altinak come to mind. KUO, the manufacturer of the "Access" series, always seemed to emphasize focus slightly to the red, so in this respect the SVX125D may be better balanced for AP, I don't know. Either way, I believe most AP'ers will be very happy with their images from the optically similar SVX125D ED doublet. Or, one can buy a far more expensive triplet.

 

Regarding the weight and portability "sweet spot," my SVA125 weighs almost exactly the same as my Celestron Edge HD 8". Given the former's longer tube, it does have a more clumsy form factor but it is very "mount-able" on my AVX. Also, unlike the Edge, it does not have a built-in and convenient handle. Neither telescope is "grab-and-go" in any sense but the OTA and mount are both very manageable. I'm assuming the SVX125D will be very similar here. I also purchased the SVA125 case (I assume that will be part of the SVX125D price?) and it is robust and well-made. My case is exactly sized for the OTA, which means it is too short to accommodate the star diagonal.

 

I have had no problems whatsoever reaching thermal equilibrium. I pretty much always set up the telescope near sunset, then go inside for an hour, so YRMV. I assume the SVX125D uses a different focuser so I won't comment except to say my Chinese focuser works great both for visual and AP (manual focus only so-far).

 

I have one little nit, and it may be specific to my Chinese-made version. There is an adapter for 2" eyepiece accommodation that unscrews to install the field flattener in its place. There are three set screws on this adapter to hold the eyepiece (or star diagonal) 2" barrel in-place. One of these came stripped. I was able to re-tap it but I don't think all of you would have the tooling or experience to do so. What did I think? "Cheeeep," and really, this is a truly minor glitch.

 

BTW, this sort of telescope also makes a fine solar telescope provided you obtain an aperture filter. I ordered one of the standard sizes--very slightly oversized--from Thousand Oaks Optical, then epoxied four disks of the correct thickness cut from wine corks to the inside of the solar filter for a snug fit on the dew shield. Do this carefully for the filterr must never just fall off: your eyes depend on it. It works great!

 

Congrats to Stellarvue and best wishes for a well-received product launch.

 

A happy SVA125 owner,

 

Don


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#15 MortonH

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Posted 03 January 2021 - 03:00 AM

This may be a dumb question, but would the image through an SVX 127mm doublet with 0.99 Strehl be essentially the same as the image through an SVX 130mm triplet with 0.99 Strehl?  If not, how would they differ?

Fewer elements can mean higher contrast but that depends on a bunch of variables.


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#16 RadioAstronomer

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Posted 03 January 2021 - 03:33 AM

If the SVX127D is as good as my SVX125D it will truly be an exceptional performer. I was on the hunt for a quality 5" doublet a few months ago and when I saw a SVX125D on the classifieds I had to jump in.

Scope has incredibly sharp optics, an excellent star test,  and no visible CA at 243x (which is as high as I go with a 4mm EP).


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#17 bobhen

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Posted 03 January 2021 - 09:21 AM

HERE is a link to the TS website and their Photoline 125mm F7.8 Ed Doublet using FPL 53 glass.  The price would be around $1,600 USD plus shipping. It’s the same scope as the SV 125 that is reviewed in this thread (post 14) but for less money.

 

Bob



#18 dhferguson

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Posted 03 January 2021 - 12:01 PM

Cheers,

 

The telescope listed in Post #17 link is very similar but not quite the same., First, the adapter at the eyepiece end is different. Second, TS does not test/adjust/QC their Chinese imports. Alan at SV says they returned over half of the Access scopes due to subspec (< 0.95 Strehl) optics and other problems. I suspect this is one reason SV no longer offers the Access line.

 

Happy observing always,

 

Don



#19 Heywood

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Posted 04 January 2021 - 08:34 PM

Thinking of picking one of these up. The only other telescope I've ever really used is my Stellarvue 90mm fluorite triplet that I really enjoy. This will be for visual use only. Is it a nice jump from 90mm? I was thinking of their SVX130....but this is half the cost. 

 

Did Stellarvue mention when the new SVX127D telescopes would actually be available to ship to the buyers?  Soon?  Not so soon?  Late in the year?

 

Thank you.



#20 121601

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Posted 04 January 2021 - 10:29 PM

Did Stellarvue mention when the new SVX127D telescopes would actually be available to ship to the buyers?  Soon?  Not so soon?  Late in the year?

 

Thank you.

Hello, don't recall but I would send him a note to get notified:  vic@stellarvue.com .  This could turn out like his 102EDT f/6 and was produced in only 1 limited run.

 

It was also good to see they appear to be employing interferometry not only after the lens is done, but during figuring.  Roland Christen of AP pointed the critical importance of this iterative process in customizing lenses.  (I think of it simply as like super fine tuning collimation on a Dob.)  Sounds like a premium grab and go.

 

CS
 


Edited by 121601, 04 January 2021 - 10:41 PM.


#21 Tyson M

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Posted 04 January 2021 - 11:53 PM

This is basically the retake on the FS128, just with better mechanics and likely optical quality. F8 doublet is perfect for visual observers like myself.

I'm in on this one. Not available until the summer so I got time to save up.

Edited by Tyson M, 05 January 2021 - 12:28 AM.

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#22 RadioAstronomer

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Posted 05 January 2021 - 01:42 AM

This is basically the retake on the FS128, just with better mechanics and likely optical quality. F8 doublet is perfect for visual observers like myself.

I'm in on this one. Not available until the summer so I got time to save up.

Reminds me of that time that I compared my SVX125D with a friend's FS-128 on a night with good seeing. Both scopes provided the exact same level of detail on planets and luna. These SV refractors with optics figured/tweaked in-house are keepers.


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#23 ovgjr

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Posted 26 January 2021 - 04:35 PM

It would help a lot if you could tell us about the SVX127D.  It doesn't appear on the Stellarvue website, and I, for one, have never heard of it.  Is it a doublet?  Triplet?  Focal ratio?  Price?  Availability?

 

Thank you.

It is an f8 5" doublet. Price is $3495 with 3" Feathertouch focuser. Only 100 will be made.


Edited by ovgjr, 26 January 2021 - 08:37 PM.


#24 ovgjr

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Posted 26 January 2021 - 05:00 PM

I actually prefer a well figured doublet to a triplet for visual. At f8 the color correction should be excellent. I will put down the $500 deposit and get on the list. Feathertouch focuser is a must.


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#25 Thomas Marshall

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Posted 26 January 2021 - 05:36 PM

We will know when they leave the land of unicorns and someone points one up at the sky.

 

’Til then, we will all enjoy months of speculation.popcorn.gif popcorn.gif

"We will know when they leave the land of unicorns and someone points one up at the sky," - and observes the wonders of "Monoceros". 


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