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Update on my SW ED150 order...

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#551 YAOG

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Posted 10 August 2018 - 10:15 PM

Carbon stars are always great to observe. I just swiped a list and imported them to my tablet to look at next time I'm out. Now if only the sky would clear up...

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#552 jrbarnett

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Posted 10 August 2018 - 10:28 PM

Jim,

Any chance you verified the scope is a full 150mm. Just curious as I know the early 120s were stopped down.

I have suspicions that the draw tube may be too long as I noted edge of field darkening (vignetting) with widest field eyepieces.  It does have a very long draw tube and with a compression adapter only slightly longer than the stock two screw diagonal retention ring, I couldn't achieve focus with many eyepieces (i.e., not enough inward focus).  Not sure the culprit may be the extra long adapter flange between the whitr focuser and black OTA end plate.

 

With a little less distance there you could get away with a shorter draw tube, likely reducing vignetting, shorten the OTA by an inch or more (which would let you either shrink the case or add more and better padding inside the case).

 

 

Or you could opt for a pricey 2" prism diagonal which has shorter glass path than a mirror diagonal, and call it a day.  I'll try and check baffle placement and cut-ins in the light cone between rear port and objective this weekend.

 

Best,

 

Jim


 

#553 Daniel Mounsey

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Posted 12 August 2018 - 08:03 AM

That’s odd Jim. How are the fires treating you now? Have you had a decent night?  I saw your comments on how it compared to the sky watcher 120 ED. I’ve used four 120ED’s and I think the 150ED was a cut above if anything. Thoughts welcome.


 

#554 25585

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Posted 12 August 2018 - 08:08 AM

John I have seen those rings shift from transit damage a good few times, the spots of glue would still be visible. I am not saying you are wrong but they slip in their threads very easily being so thin. A bit like a slide hammer effect. Looking at skywatchers history of making optics for a very long time now I seriously doubt any left the factory with defects. Especially given the fact these were anticipated eagerly and publicly, what company in their right mind would blow it carelessly.

To assemble the cell retaining ring cross threaded is a real schoolboy error and in my honest opinion unlikely for an experienced company aware of the hype.

As Synta are in China, a country and culture far far away from our own, I wonder if the western hopes and expectations - especially of a very small demographic globally , initially at least, have much or any impact on a big company.

 

To Synta, the 150 will be just another product I imagine. Sure one up from an achro optically, but the rest I have my doubts on.

 

Even the much more upmarket Esprit triples have their issues, from triplet lens, to finish, to case lining fluff getting inside an OTA.

 

So I am glad HT and FLO are aware of and check SW refractors before dispatching to buyers, if requested. However the whole issue of buying expensive glass by online, for larger objects in manufacturer packing generally, has been as much the issue as QC.

 

I have had no trouble with big Newtonian  (well 12 inch max) mirrors, but those come boxed separately to the tube, not ready mounted. Perhaps there is a case for Borg-like component disassembly and reassembly in the construction and shipping of refractors with 100mm+ objective lens cell. 


Edited by 25585, 12 August 2018 - 08:11 AM.

 

#555 CHASLX200

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Posted 12 August 2018 - 08:27 AM

Dose this scope have a finder shoe built in like my SW150 Mak?


 

#556 Daniel Mounsey

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Posted 12 August 2018 - 08:48 AM

Yea, it comes standard with a Vixen style dove shoe. I’ll update you tomorrow.


 

#557 John Huntley

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Posted 12 August 2018 - 08:52 AM

Dose this scope have a finder shoe built in like my SW150 Mak?

Yes:

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#558 CHASLX200

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Posted 12 August 2018 - 09:03 AM

I like the built in shoe on my SW150 Mak and my low profile holder works good for the SW150 Mak. Be fun to compare the two scopes and keep the winner.

 

23upov9.jpg


Edited by CHASLX200, 12 August 2018 - 09:04 AM.

 

#559 jrbarnett

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Posted 12 August 2018 - 11:41 AM

Okay another session with the scope under the belt, under much better seeing conditions albeit worse transparency.  The occasion was the de-consecration of OFLI's home observing field in Sonoma.  The property is being sold, and this was our final session from the site.  12 years.  Wow.  Tempus fugit.

 

It was fun sharing the big Skywatcher with the others.  Targets primarily were planets (Mars, Saturn and Jupiter),  a couple of bright summer globulars, easy double stars and an opportunity to re-evaluate color correction and the star test (unfiltered this time) under better conditions.

 

The best news is that the optic appears to be centered with no evidence of wedge or similar errors.  Star testing pretty much corroborated my earlier results under poorer seeing - an adequate but not fantastic optic.  Better'n 1/4 wave but just at or even a little shy of 1/5 wave, and a bit over-corrected.  Smooth enough but not super smooth.

 

I would put seeing last night around Pickering 7.  For planets that were better placed above the slop (Jupiter early in the session and Saturn following) the scope did a credible job.  In keeping with being a good but not great optic, usefulness in good seeing started to break down pretty early as magnification was ramped up.  At 25x per inch (150x) a very slight deterioration of image sharpness entered the equation, though more detail was seen on both gas giants despite the slight softening.  At 33x per inch (200x) things got pretty soft frankly to the point where the optic, not seeing, was doing more harm to the image than magnification was producing additional detail.  As is typical Saturn remained a little "tighter" than Jupiter at this magnification level, but at 33x per inch I was definitely trading image quality for scale.  While I'm not exactly disappointed, and my intended use of this instrument (more on this in a second) isn't affected by these results, this would not be my first choice in refractors for a planetary aficionado.  IMO the ES 127ED is the better bet, having now used four samples of that scope and been generally impressed with planetary performance up to about 40x per inch in good seeing.  But I digress.

 

My intended use of this scope is primarily deep sky, wide field observing, specifically in the context of guiding mounted binoculars to target regions using a GLP.  It replaces a United Optics 6" f/5.9 achromat in this role.  For this purpose it'll be a fun scope, with one qualification.  The qualification being that the case is ridiculously huge (oversized).  So much so that it makes it patently unpleasant to load, unload and transport the scope.  Figure the scope in its case takes up 4x the cargo area in a vehicle as the 6" f/5.9 achromat in a padded lighting stand bag (soft case).  I am noodling sourcing a padded carry bag for the OTA from Pacific Designs and reserving the metal case for storage.

 

I spent a good deal of time working on the focuser earlier in the day yesterday.  I still cannot determine what exactly is making the irregular "clicking" as the draw tube is racked in and out.  I did manage to reduce the amplitude of the irregularity by carefully paralellizing the roller with the draw tube flat and messing with tension "teeter-totter" screws, as well as four point tilt (the little rubber o-rings at each corner of the roller assembly attachment plate are pretty cool/clever.  Next project is to use a sharpening stone to flatten the draw tube flat.  I definitely need a replacement focuser, and would like a stock replacement, since even tuned carefully this one in current condition is a huge let down at any but minimal magnification.

 

Color correction.  Hmm...a little better in better seeing unsurprisingly.  But still plenty colorful on our old friend Vega.  Definitely deep blue tinging violet CA on that star even at lower magnification.  The issue of imperfect correction was made even more obvious by head to head comparison with a nearby FS-128.  Ignorance is bliss.  :grin:  200x on Vega is dispels any notion or pretension about this being an APO.  On the other hand, flase color on Saturn was hard to find.  But False color on Juiter was there albeit pretty subtle even at higher magnification.  All by itself with no better reference would likely leave the owner happy with the amount of false color.  Coming from a fast achromat, I'm tickled pink with the color correction compared to the achromat I replaced with this scope.

 

More to come...

 

- Jim


 

#560 mogur

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Posted 12 August 2018 - 11:59 AM

I have had no trouble with big Newtonian  (well 12 inch max) mirrors, but those come boxed separately to the tube, not ready mounted. Perhaps there is a case for Borg-like component disassembly and reassembly in the construction and shipping of refractors with 100mm+ objective lens cell.


What Newtonians have you ordered that pack the mirrors separate? My Meade, Celestron, and ES all came with the mirrors already mounted.


 

#561 mogur

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Posted 12 August 2018 - 12:06 PM

Jim, the irregular clicking doesn't sound like a shaft problem as I would think that to be pretty regular as the shaft turned. It sounds more like a bad bearing somewhere.


 

#562 starman876

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Posted 12 August 2018 - 12:15 PM

Okay another session with the scope under the belt, under much better seeing conditions albeit worse transparency.  The occasion was the de-consecration of OFLI's home observing field in Sonoma.  The property is being sold, and this was our final session from the site.  12 years.  Wow.  Tempus fugit.

 

It was fun sharing the big Skywatcher with the others.  Targets primarily were planets (Mars, Saturn and Jupiter),  a couple of bright summer globulars, easy double stars and an opportunity to re-evaluate color correction and the star test (unfiltered this time) under better conditions.

 

The best news is that the optic appears to be centered with no evidence of wedge or similar errors.  Star testing pretty much corroborated my earlier results under poorer seeing - an adequate but not fantastic optic.  Better'n 1/4 wave but just at or even a little shy of 1/5 wave, and a bit over-corrected.  Smooth enough but not super smooth.

 

I would put seeing last night around Pickering 7.  For planets that were better placed above the slop (Jupiter early in the session and Saturn following) the scope did a credible job.  In keeping with being a good but not great optic, usefulness in good seeing started to break down pretty early as magnification was ramped up.  At 25x per inch (150x) a very slight deterioration of image sharpness entered the equation, though more detail was seen on both gas giants despite the slight softening.  At 33x per inch (200x) things got pretty soft frankly to the point where the optic, not seeing, was doing more harm to the image than magnification was producing additional detail.  As is typical Saturn remained a little "tighter" than Jupiter at this magnification level, but at 33x per inch I was definitely trading image quality for scale.  While I'm not exactly disappointed, and my intended use of this instrument (more on this in a second) isn't affected by these results, this would not be my first choice in refractors for a planetary aficionado.  IMO the ES 127ED is the better bet, having now used four samples of that scope and been generally impressed with planetary performance up to about 40x per inch in good seeing.  But I digress.

 

My intended use of this scope is primarily deep sky, wide field observing, specifically in the context of guiding mounted binoculars to target regions using a GLP.  It replaces a United Optics 6" f/5.9 achromat in this role.  For this purpose it'll be a fun scope, with one qualification.  The qualification being that the case is ridiculously huge (oversized).  So much so that it makes it patently unpleasant to load, unload and transport the scope.  Figure the scope in its case takes up 4x the cargo area in a vehicle as the 6" f/5.9 achromat in a padded lighting stand bag (soft case).  I am noodling sourcing a padded carry bag for the OTA from Pacific Designs and reserving the metal case for storage.

 

I spent a good deal of time working on the focuser earlier in the day yesterday.  I still cannot determine what exactly is making the irregular "clicking" as the draw tube is racked in and out.  I did manage to reduce the amplitude of the irregularity by carefully paralellizing the roller with the draw tube flat and messing with tension "teeter-totter" screws, as well as four point tilt (the little rubber o-rings at each corner of the roller assembly attachment plate are pretty cool/clever.  Next project is to use a sharpening stone to flatten the draw tube flat.  I definitely need a replacement focuser, and would like a stock replacement, since even tuned carefully this one in current condition is a huge let down at any but minimal magnification.

 

Color correction.  Hmm...a little better in better seeing unsurprisingly.  But still plenty colorful on our old friend Vega.  Definitely deep blue tinging violet CA on that star even at lower magnification.  The issue of imperfect correction was made even more obvious by head to head comparison with a nearby FS-128.  Ignorance is bliss.  grin.gif  200x on Vega is dispels any notion or pretension about this being an APO.  On the other hand, flase color on Saturn was hard to find.  But False color on Juiter was there albeit pretty subtle even at higher magnification.  All by itself with no better reference would likely leave the owner happy with the amount of false color.  Coming from a fast achromat, I'm tickled pink with the color correction compared to the achromat I replaced with this scope.

 

More to come...

 

- Jim

Very interesting report.  Independent report on a scope is the best.  I will try and provide the type of report on the APM 152.   I wonder what the Strehl is of the SW150.  It is around 93 for the APM 152. Well, that is what they state on their test data that comes with the scope. I think it is great they provide a test report of each lens.   Interesting with your comment on the ED127ED.  I cobbled one together yesterday using that lens and was very happy with the outcome.  However, even though on both sides of focus i saw the same difraction rings without color.  On mars I could see a bit of blue on the edge of the planet but only on one edge. 


Edited by starman876, 12 August 2018 - 12:19 PM.

 

#563 janapier

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Posted 12 August 2018 - 12:18 PM

 ...

Star testing pretty much corroborated my earlier results under poorer seeing - an adequate but not fantastic optic.  Better'n 1/4 wave but just at or even a little shy of 1/5 wave, and a bit over-corrected.  Smooth enough but not super smooth.

...

At 33x per inch (200x) things got pretty soft frankly to the point where the optic, not seeing, was doing more harm to the image than magnification was producing additional detail.  

...

Color correction.  ...  200x on Vega is dispels any notion or pretension about this being an APO.  On the other hand, flase color on Saturn was hard to find.  But False color on Juiter was there albeit pretty subtle even at higher magnification.  All by itself with no better reference would likely leave the owner happy with the amount of false color.  Coming from a fast achromat, I'm tickled pink with the color correction compared to the achromat I replaced with this scope.

 

More to come...

...

- Jim

Nice review that reveals, in conjunction with others, what more you get when you buy the Esprit rather than this new doublet, albeit at more than twice the price: „etched“ and „tack-sharp“ planetary images @ 200x and higher mag, no image breakdown while observing the moon @400x, and no color on either Vega or Venus other than atmospheric dispersion. 


Edited by janapier, 12 August 2018 - 12:20 PM.

 

#564 Bomber Bob

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Posted 12 August 2018 - 12:27 PM

At 33x per inch (200x) things got pretty soft frankly to the point where the optic, not seeing, was doing more harm to the image than magnification was producing additional detail.

 

Thanks for the report Jim!  Yikes!  That is sub-par for a 6" refractor - regardless of design, glass type, or country of origin.  My beat up old 1971 Criterion RV-6 F8 Newtonian is sharp at 40x per inch.  My APM is sharp at 80x per inch.  I know the impact of local conditions, but at the P-7 seeing you reported... I hope it can be attributed to the post-shipping repairs, and other mechanical factors.


 

#565 noisejammer

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Posted 12 August 2018 - 12:56 PM

In one regard the SW ED150 blows away the TOA-150 for visual - it's totally equilibriated within 30-45 minutes.  I've used TOA-150s at star parties that *never* reached equilibrium as temperatures dropped through the night.  Huge glass mass (two 6" ED elements plus a third element) and huge air gaps (necessary to achieve the phenomenal color correction for such a big refractor, are the culprits.  That and you could get 6 or 7 of the SWs for the price of one TOA-150, and the TOA-150 weights twice as much as this scope, so also requires a bigger mount.

Jim, perhaps we can agree to disagree on this one. I'm thrilled that many more folk will get to experience large, well corrected refractors. They do make the exotic triplets look like white elephants. And yet ...

 

I had my TOA150 out at Starfest and over Friday evening ran it through lots of showpieces under excellent seeing. Over the four hours I was entertaining, the lineup was never shorter than four people. The temperature fell 15C and none complained about the view. In my ten years with the scope, I've never been disappointed. Maybe I'm just easily pleased - I don't use any scope at more than about 40-45x per inch.

 

For what it's worth, I don't use the 10-lb tube weight. I suspect this huge heat capacitor is as big a culprit as any in degrading the instrument's performance.


 

#566 jrbarnett

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Posted 12 August 2018 - 12:58 PM

Very interesting report.  Independent report on a scope is the best.  I will try and provide the type of report on the APM 152.   I wonder what the Strehl is of the SW150.  It is around 93 for the APM 152. Well, that is what they state on their test data that comes with the scope. I think it is great they provide a test report of each lens.   Interesting with your comment on the ED127ED.  I cobbled one together yesterday using that lens and was very happy with the outcome.  However, even though on both sides of focus i saw the same difraction rings without color.  On mars I could see a bit of blue on the edge of the planet but only on one edge. 

Given that your blue was on one edge only, I'd suspect either atmospheric refraction, with the red on the other edge being invisible due to the natural ruddy glare of the planet.  Alternately with particularly good apparitions I've seen dark features on the limb look bluish.

 

But yeah, I can reel in false color on the JOC 127EDs too.  It's just that the quality of the optics tends to be pretty consistently good now on that OG.  I haven't yet seen one of the FCD100 versions though.

 

Best,

 

Jim 


 

#567 jrbarnett

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Posted 12 August 2018 - 01:07 PM

Nice review that reveals, in conjunction with others, what more you get when you buy the Esprit rather than this new doublet, albeit at more than twice the price: „etched“ and „tack-sharp“ planetary images @ 200x and higher mag, no image breakdown while observing the moon @400x, and no color on either Vega or Venus other than atmospheric dispersion. 

I don't find the Moon to be a very good test of optics.  Even mediocre scopes tend to be able to get decent results at high magnification due to the abundance of light.

 

It's worth noting tough that the Esprit optics and these optics and the cheapo 6" acrhomat optics are all fabricated in pretty much the same manner by the same people using the same methods and machines.  I suspect that what you get in Esprit land is a higher rate of rejection of elements, more attention to testing and more robust build in terms of both OTA and lens cell.

 

Jim, perhaps we can agree to disagree on this one. I'm thrilled that many more folk will get to experience large, well corrected refractors. They do make the exotic triplets look like white elephants. And yet ...

 

I had my TOA150 out at Starfest and over Friday evening ran it through lots of showpieces under excellent seeing. Over the four hours I was entertaining, the lineup was never shorter than four people. The temperature fell 15C and none complained about the view. In my ten years with the scope, I've never been disappointed. Maybe I'm just easily pleased - I don't use any scope at more than about 40-45x per inch.

 

For what it's worth, I don't use the 10-lb tube weight. I suspect this huge heat capacitor is as big a culprit as any in degrading the instrument's performance.

Interesting point about the big counterweight.  I hadn't thought of that.  But I suspect also that you may not have been pushing much magnification if you were chasing bright showpiece objects for visitors.  Thermal issues tend to manifest at high magnification rather than low, though tube currents may affect low power views with some instability of best focus.

 

Also a good point on the magnification limits many of us use most often.  I too tend to hover in that 25x to 40x per inch range.

 

Regards,

 

Jim


 

#568 Tyson M

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Posted 12 August 2018 - 01:10 PM

My intended use of this scope is primarily deep sky, wide field observing, specifically in the context of guiding mounted binoculars to target regions using a GLP. It replaces a United Optics 6" f/5.9 achromat in this role. For this purpose it'll be a fun scope, with one qualification. The qualification being that the case is ridiculously huge (oversized). So much so that it makes it patently unpleasant to load, unload and transport the scope. Figure the scope in its case takes up 4x the cargo area in a vehicle as the 6" f/5.9 achromat in a padded lighting stand bag (soft case).


Color correction. Hmm...a little better in better seeing unsurprisingly. But still plenty colorful on our old friend Vega. Definitely deep blue tinging violet CA on that star even at lower magnification. The issue of imperfect correction was made even more obvious by head to head comparison with a nearby FS-128. Ignorance is bliss. :grin: 200x on Vega is dispels any notion or pretension about this being an APO. On the other hand, flase color on Saturn was hard to find. But False color on Juiter was there albeit pretty subtle even at higher magnification. All by itself with no better reference would likely leave the owner happy with the amount of false color. Coming from a fast achromat, I'm tickled pink with the color correction compared to the achromat I replaced with this scope.

- Jim


Hey Jim, for wide field and deep sky usage wouldn't the achro do the same job in a much smaller package? Unless you are looking for smaller deep sky targets like planetary nebula or wide fields clusters that include very bright stars- where the better color correction would be more desirable?
 

#569 jrbarnett

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Posted 12 August 2018 - 01:12 PM

Jim, the irregular clicking doesn't sound like a shaft problem as I would think that to be pretty regular as the shaft turned. It sounds more like a bad bearing somewhere.

The only bit I haven't yet had apart is the fine focuser reducing gear assembly.  There are no true bearings in any other part of the ficuser,  All contact points appear to be Teflon pads.

 

Because waxing the draw tube flat with cutting wax seemed to help almost as much as adjusting parallelism of the roller to the draw tube flat, I am wondering is the impact (or impacts - the tail of my scope was loose in the box with the fine focus knob no doubt merrily slamming against the lit more than once on its journey) may have caused damage to the roller itself or to thin edge contact surfaces along the drawtube.

 

I'll let you know what honing the draw tube flat section accomplishes.

 

Best,

 

Jim


 

#570 starman876

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Posted 12 August 2018 - 01:15 PM

Given that your blue was on one edge only, I'd suspect either atmospheric refraction, with the red on the other edge being invisible due to the natural ruddy glare of the planet.  Alternately with particularly good apparitions I've seen dark features on the limb look bluish.

 

But yeah, I can reel in false color on the JOC 127EDs too.  It's just that the quality of the optics tends to be pretty consistently good now on that OG.  I haven't yet seen one of the FCD100 versions though.

 

Best,

 

Jim 

Hi Jim

That is what I was seeing.  Blue tinge on one edge and a red tinge on the other edge.  I suspected as much. It is good to talk these points out with other astronomers.   everyone has a bit to add from their experiences over the years.   This is a great forum in where everyone benefits as long as we keep the conversations within reality of what can be normally expected.


 

#571 JKAstro

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Posted 12 August 2018 - 01:27 PM

Okay another session with the scope under the belt, under much better seeing conditions albeit worse transparency.  The occasion was the de-consecration of OFLI's home observing field in Sonoma.  The property is being sold, and this was our final session from the site.  12 years.  Wow.  Tempus fugit.

 

It was fun sharing the big Skywatcher with the others.  Targets primarily were planets (Mars, Saturn and Jupiter),  a couple of bright summer globulars, easy double stars and an opportunity to re-evaluate color correction and the star test (unfiltered this time) under better conditions.

 

The best news is that the optic appears to be centered with no evidence of wedge or similar errors.  Star testing pretty much corroborated my earlier results under poorer seeing - an adequate but not fantastic optic.  Better'n 1/4 wave but just at or even a little shy of 1/5 wave, and a bit over-corrected.  Smooth enough but not super smooth.

 

I would put seeing last night around Pickering 7.  For planets that were better placed above the slop (Jupiter early in the session and Saturn following) the scope did a credible job.  In keeping with being a good but not great optic, usefulness in good seeing started to break down pretty early as magnification was ramped up.  At 25x per inch (150x) a very slight deterioration of image sharpness entered the equation, though more detail was seen on both gas giants despite the slight softening.  At 33x per inch (200x) things got pretty soft frankly to the point where the optic, not seeing, was doing more harm to the image than magnification was producing additional detail.  As is typical Saturn remained a little "tighter" than Jupiter at this magnification level, but at 33x per inch I was definitely trading image quality for scale.  While I'm not exactly disappointed, and my intended use of this instrument (more on this in a second) isn't affected by these results, this would not be my first choice in refractors for a planetary aficionado.  IMO the ES 127ED is the better bet, having now used four samples of that scope and been generally impressed with planetary performance up to about 40x per inch in good seeing.  But I digress.

 

My intended use of this scope is primarily deep sky, wide field observing, specifically in the context of guiding mounted binoculars to target regions using a GLP.  It replaces a United Optics 6" f/5.9 achromat in this role.  For this purpose it'll be a fun scope, with one qualification.  The qualification being that the case is ridiculously huge (oversized).  So much so that it makes it patently unpleasant to load, unload and transport the scope.  Figure the scope in its case takes up 4x the cargo area in a vehicle as the 6" f/5.9 achromat in a padded lighting stand bag (soft case).  I am noodling sourcing a padded carry bag for the OTA from Pacific Designs and reserving the metal case for storage.

 

I spent a good deal of time working on the focuser earlier in the day yesterday.  I still cannot determine what exactly is making the irregular "clicking" as the draw tube is racked in and out.  I did manage to reduce the amplitude of the irregularity by carefully paralellizing the roller with the draw tube flat and messing with tension "teeter-totter" screws, as well as four point tilt (the little rubber o-rings at each corner of the roller assembly attachment plate are pretty cool/clever.  Next project is to use a sharpening stone to flatten the draw tube flat.  I definitely need a replacement focuser, and would like a stock replacement, since even tuned carefully this one in current condition is a huge let down at any but minimal magnification.

 

Color correction.  Hmm...a little better in better seeing unsurprisingly.  But still plenty colorful on our old friend Vega.  Definitely deep blue tinging violet CA on that star even at lower magnification.  The issue of imperfect correction was made even more obvious by head to head comparison with a nearby FS-128.  Ignorance is bliss.  grin.gif  200x on Vega is dispels any notion or pretension about this being an APO.  On the other hand, flase color on Saturn was hard to find.  But False color on Juiter was there albeit pretty subtle even at higher magnification.  All by itself with no better reference would likely leave the owner happy with the amount of false color.  Coming from a fast achromat, I'm tickled pink with the color correction compared to the achromat I replaced with this scope.

 

More to come...

 

- Jim

Sounds very much like what one would expect at this price point.  Seems this post should be post #1 of a new thread, so that prospective buyers have a chance of reading it.


 

#572 jrbarnett

jrbarnett

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Posted 12 August 2018 - 01:36 PM

Hey Jim, for wide field and deep sky usage wouldn't the achro do the same job in a much smaller package? Unless you are looking for smaller deep sky targets like planetary nebula or wide fields clusters that include very bright stars- where the better color correction would be more desirable?

Hi Tyson.  Actually for wider field observing color correction still matters if there us anything bright-ish in the FOV.  The f/5.9 6" achromat that this scope replaced was a nice scope but definitely showed visible false color on bright stars even in low power fields.

 

Best,

 

Jim


 

#573 jrbarnett

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Posted 12 August 2018 - 01:41 PM

Sounds very much like what one would expect at this price point.  Seems this post should be post #1 of a new thread, so that prospective buyers have a chance of reading it.

Hi JK.  I'm actually working on a formal review article for this scope.  It's an important enough scope from a new capability at a low pricepoint perspective that such a persistent easy to find piece should prove useful.

 

Best,

 

Jim


 

#574 janapier

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Posted 12 August 2018 - 02:04 PM

I don't find the Moon to be a very good test of optics.  Even mediocre scopes tend to be able to get decent results at high magnification due to the abundance of light.

 

It's worth noting tough that the Esprit optics and these optics and the cheapo 6" acrhomat optics are all fabricated in pretty much the same manner by the same people using the same methods and machines.  I suspect that what you get in Esprit land is a higher rate of rejection of elements, more attention to testing and more robust build in terms of both OTA and lens cell.

 

...

Yeah, the moon tends to yield impressive images even in mediocre scopes. But „impressive“ does not equal „really good“. There are targets on the moon that will challenge optics, dependent on the lighting conditions. The craterlets in plato come to mind, as well as certain lunar domes and rille systems. There is this difference between „Now as you say it, I am actually seeing it“ and „Wow, look at that structure! This image is impossibly sharp!“.

And yes, the optics are made by the same people on the same machines. But as you say: there may be more money for QC and mechanically better lens cells. There might also be more forgiving designs using one lens more and better-suited albeit more expensive glas combinations.


 

#575 CHASLX200

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Posted 12 August 2018 - 03:40 PM

Yes:

Looking at that pic i don't think my low profile rings will work. I have another set if rings that are higher that should work fine.


 


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