New affordability breakthrough

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  • Member since
    March, 2008
New affordability breakthrough
Posted by Antitax on Thursday, December 19, 2013 8:16 AM

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p6679_TS-PHOTOLINE-130mm-f-7-Triplet-APO---FPL-53---2-5--RPA-Auszug.html

   This is in Europe but will no doubt be sold in North America and other continents under different names. For the first time a large triplet apo with premium PFL-53 glass is sold for 2.200€. For that amount of cash you used to obtain only FPL-51 triplets with a good matching lanthanum lens, but FPL-53 is unbeatable.

   Even better, the upgraded 130mm is equipped with a clone of the Feather Touch 2.5" focuser (a hybrid Crayford/rack-and-pinion), it seems large enough to avoid vigneting with regular sensors, and it also sports self-centering adapters in 2" and 1.25" sizes.

   The other high-grade 130mm apo's I know of are the APM (6,800€), the Officina Stellare (7,315€), and the Takahashi (5,550€). I willingly ignore Astro-Physics because although perfect in their lenses and gears, making people wait several years for superexpensive things is insanely horrible service. For very large sums you should have excellent service, and excellent service implies it should be prompt.

    I believe Astro-Physics could very well have hired and trained more staff a couple decades ago, when delivery times started growing crazy (recently a guy in Cloudy Nights triumphantly announced he got his Astro-Physics scope delivered after 9 years and 8 months! Yeah, way to go, dude! Lucky you didn't die of old age before they started bothering with your order). With more qualified staff they would produce more good scopes without letting clients grow ZZ-Top beards, and not have to compromise quality.

   I'm no longer a fan of Questar for the same reason: after asking many thousands for a seven-inch they don't bother to serve with speed adequate to the price. In contrast, even the 6-incher from TS are delivered from stock, or with a three-weeks delay at most.

   There you have it, mid-size apos for a price most everyone can afford after some saving, the only wait will be while filling the piggy bank. By the way, TS also has a 100mm f/5.8 quadruplet (front doublet plus rear corrector for 2,200€ to compete with TeleVue's NP101), which is also sold under Stellarvue's logo. Last, non-european-union customers can deduce the hated VAT tax, and make even better deals on TS gear.

Tags: no rip-off

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

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  • From: Texas
Posted by chipdatajeffB on Thursday, December 19, 2013 9:37 AM

Sounds good to me.

I have seen very similar offerings from SkyWatcher in the Esprit line. They are excellent values and compete favorably -- even photographically -- with premium refractors costing twice as much.

 

And, yes, being able to ship from stock is a huge boon to the customer.

 

A plus for imagers is the built-in field flattener (usually these are optional extras on the premium APOs).

 

The major reason the AP line has such a wait line is that Roland does the optical alignments personally, and he is a stickler for accuracy. I don't view the wait as part of their "service", however. Their aftermarket service and support is superb.

 

Where do you get the idea that the Televue NP 101 is part of the Stellarvue lineup?

The universe is not only stranger than we imagine, it's stranger than we CAN imagine. --- JBS Haldane

Come visit me at Comanche Springs Astronomy Campus (we're on Google Maps) in Texas.

www.3rf.org

  • Member since
    March, 2008
Posted by Antitax on Thursday, December 19, 2013 11:00 AM

chipdatajeffB

Where do you get the idea that the Televue NP 101 is part of the Stellarvue lineup?

 
   That's not what I wrote, you overlooked a parenthesis.

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

  • Member since
    March, 2008
Posted by Antitax on Thursday, December 19, 2013 11:08 AM

chipdatajeffB

The major reason the AP line has such a wait line is that Roland does the optical alignments personally, and he is a stickler for accuracy.

   And when he dies he plans to leave the commenced work unfinished, and his staff unemployed? If he's a master he should have apprentices, and, God forbid! create jobs.

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

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  • Member since
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  • From: Texas
Posted by chipdatajeffB on Friday, December 20, 2013 5:08 AM

Antitax
 
chipdatajeffB

Where do you get the idea that the Televue NP 101 is part of the Stellarvue lineup?

 

 

 
   That's not what I wrote, you overlooked a parenthesis.
 

Indeed I did! Thanks ...

The universe is not only stranger than we imagine, it's stranger than we CAN imagine. --- JBS Haldane

Come visit me at Comanche Springs Astronomy Campus (we're on Google Maps) in Texas.

www.3rf.org

  • Member since
    March, 2008
Posted by Antitax on Friday, December 20, 2013 9:50 AM

   I happen to have a NP-101 at home now, a friend left it here so I could dewobble (the word exists now that I made it up) its Polaris-clones mount and tripod. I also checked the focuser for play, its former owner put shims in the wrong place, slightly seperating the rack from the pinion. The teflon sleeve between the focuser housing and drawtube needed some rectification too, it was worn out a bit, I simply made it thicker with a couple strips of tape. I might add some tape depending on how much friction he wants, that's a matter of taste.

   But since we're talking astro buying power and value, and the NP-101 pops up, here's a little calculation I made: it costs 4,100€ new for the optical tube only. The main components are the four lenses, the cell, the tube, and the focuser, that's close to 600€ each.

   But for a little over 600€ you get a complete Sky-Watcher 100mm apo with dual-speed focuser, which the NP-101 does not have; you must spend a couple hundred more for that, and choose the NP-101is instead. Plus, the "basic" version vignettes badly, my friend also brought it so I would craft aperture stops of 85mm and 70mm, to see how vignetting and resolution would change. Again, you have to take the more expensive NP-101is to avoid this.

   By the way, I checked the optics on daytime views, and with an artificial and natural stars, they're excellent; the diffraction figures are colorless and smooth, but not quite as symmetrical as in my triplet, that's the accepted difference between an astrograph and a visual scope. However my 80mm triplet with dual-speed costed 646€, and is sharper than the TeleVue stopped-down to 85mm.

   At full aperture the NP-101 struggles to outresolve the 80, which seems to cut through turbulence, and provides a steadier view. And while my friend expected an f/5.4 101mm scope to be around 540mm long, it's 760mm long, retracted dewshield to retracted focuser.

   Plus, it causes weird artefacts around bright stars, the halo has two strange dark indentations, maybe because of the two slots in the shiny ring that keeps the outer lens in place. I cut a permanent stop out of matte mousepad black rubber, it reduces the useful diameter by a half-millimeter at most, and is simply stuck in the threads outside the ring. Couldn't experiment with it as yet, though.

   My apo does not cause any photo artefacts, and most others don't either. More, the flocking inside the TV unglues itself at places, but the tube is sealed. More than more, while the felt-lined dewshield keeps dew away from the lens very well, it wobbles badly when extended, and that feels cheap.

   The homemade dewshield I made for the 60mm achro I gave away has no play at all when extended; that's very easy to design, and what little play my apo's dewshield had, I removed with adhesive rubber pads instead of the original crude velours strips. The TeleVue's dewshield can't be modded however, its design precludes this.

   You get what you pay for?

Tags: you don't

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

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Posted by chipdatajeffB on Friday, December 20, 2013 12:35 PM

Hmmm ... at 3RF we have several premium APOs of different aperture. We also have several achromats. Currently, we are testing each of the different SkyWatcher Esprit models.

While we are very favorably impressed by the SkyWatchers -- especially for the price! -- there are some definite "advantages" to the premium scopes.

  1. In general, the mechanics are superior. Not that the SkyWatchers are "bad", just that the premium scopes are "better". That is to be expected, given the 2X to 4X price difference.
  2. The focusers on the premium scopes are Much better. Except for the Takahashi FSQs and TOAs, all our premium apos have two-speed FeatherTouch focusers. Again, not that the SkyWatchers are "bad", just that the premium scopes' focusers are obviously better. I don't think the difference means much for visual observing, but for imaging -- especially with extenders, Powermates, and heavy cameras, the difference can be important. We are doing our testing with Canon 60Da DSLRs, by the way.
  3. The optics in the premium scopes measure to be better (mfr-supplied Zygo readings are superior), but photographs made with them do not show obvious superiority -- until you analyze them with software. Contrast is higher on the premium scopes, for one thing. A lot depends on how and why you compare the scopes, so "superior" is a bit open for interpretation unless you stick to the specs alone.

We also have a Televue NP-101 and a 102. Neither is an "is" model. Both are good performers, on a par with the other premium apos.

Neither TV scope vignettes. This leads me to believe that either a baffle is loose or the focuser or extension is causing the problem you noticed. If neither is the case, then I am baffled (sorry!, couldn't resist!).

I suspect the spacer tabs in the retaining ring of the front optics is what's causing the indentations in the halos you noticed. They could also be the result of pinched optics, but that cause likely would also show up as warped images. If you have access to an optical test pattern, you can easily determine if the optics are pinched. Otherwise, draw a series of closely-spaced parallel lines on a cardboard target and check for warpage.

Felt absorbs moisture and is prone to changing size and shape, as well as coming loose. If flocking material is coming loose inside the tube, it is likely that excess moisture is the cause.

We have the opposite problem, as we are located on a desert plain where dry conditions prevail. Felt or velour strips in dewshields, or flocking material, tend to flatten and shrink with age and use here, so when we can we replace them with nylon hook-and-loop material (the loop side, to avoid scratching and binding) and then tends to work well. I have not tried disassembling either of the TV scopes, but even after more than a decade in our climate they are still working quite well.

On balance, I am tempted to say "Yes, you get what you pay for." However, the price difference is more than 2X and in a couple of cases even 2X above that. Especially since there is zero to very little wait time for the less expensive scopes, you have to ask yourself why you can't just as easily replace a worn SkyWatcher with another one instead of buying a premium scope?

I'm sure there are other brands that we could tout here ... but I don't have direct experience with them.

The universe is not only stranger than we imagine, it's stranger than we CAN imagine. --- JBS Haldane

Come visit me at Comanche Springs Astronomy Campus (we're on Google Maps) in Texas.

www.3rf.org

  • Member since
    March, 2008
Posted by Antitax on Friday, December 20, 2013 1:00 PM

   Here's what Tom Trusock from Cloudy Nights says:

"One of the considerations of this particular scope is that there is some vignetting due to the size of the focuser and rear elements. In the standard (non-IS) model, this is most noticeable in long term 35mm CCD exposures (smaller chip sizes pose far less of an issue). While vignetting can be compensated for by several different methods, it's not ideal, ergo the IS scopes have a larger set of rear elements and a larger internal diameter focuser draw tube to increase the field illumination, further optimizing them for imaging".

   Extracted from this review:

  http://telescopereviews.com/item.php?item_id=1749

Tags: told you

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

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  • From: Texas
Posted by chipdatajeffB on Friday, December 20, 2013 1:08 PM

I will have to try the 60Da on them to see how the light falls off from center. It isn't noticeable visually. It makes sense it would be more troublesome with larger chips, since one reason to get a larger chip is to pick up field of view, which you don't then want to have to crop away ...

Alad Dyer used a 4" TV for the photos he made for Nightwatch ... I think it was a Renaissance ...

The universe is not only stranger than we imagine, it's stranger than we CAN imagine. --- JBS Haldane

Come visit me at Comanche Springs Astronomy Campus (we're on Google Maps) in Texas.

www.3rf.org

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