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Takahashi Starbase 80 - My User Notes

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#1 agmoonsolns

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Posted 31 October 2019 - 05:22 PM

Brief rundown, more in-depth review to follow with all of the juicy details and photos.

 

Recently received the Takahashi Starbase 80mm f/10 achromatic refractor on alt-az mount. Wonderful fit and finish and pretty good optics. If you have used a Vixen 80mm f/11 refractor made in Japan whether badged as a Celestron Meade, Vixen, etc. then you already know how this will perform. The Starbase 80 is basically like these, but slightly faster and with a smidgen more chromatic aberration. 

 

Star test was good, but no where near as good as what one finds with the regular Takahashi apochromatic refractors and old fashioned long focal length achromats (like those from RAO, etc.) Did notice scattered light at medium to higher magnifications, but couldn't find any sources of glare or reflections inside the tube assembly (it's a well-made unit). Not sure if this is because of rough optical surfaces or something inside the tube assembly I can fix with flocking or flat black paint.

 

CA was pronounced on Jupiter and Sirius and still pretty significant on Saturn and Vega. I don't mind CA to a certain extent, but I am very sensitive to it and this much color (the same as you will find in any decent 80mm f/10 to f/11 refractor) really kind of bugs me. I am used to my achromats being much slower and better corrected than this.

 

Handles magnification fairly well up to about 119x and then the images start to fall apart rapidly with increasing magnification. For an 80mm, this isn't too bad, almost 40x per inch which is pretty standard average for most inexpensive, mass produced telescopes.

 

I compared it to a 76mm/1200 RAO (vintage achromat) and the AT80 (currently made ED apochromat) and both were very much superior to the Starbase in terms of optics, mechanics/tube assembly, and performance.

 

The RAO had considerably better correction of SA, CA, etc. and delivers a textbook perfect star test. The RAO is also able to deliver sharper images up to much higher magnifications (I routinely use a 6mm for 200x on the moon and double stars with this) and it delivers higher contrast images.

 

The AT80ED is a marvel - superb color correction, short/fast tube assembly with buttery smooth 2" focuser, solid tube assembly construction, and a very nice lens. It's unfair to compare the Starbase to the AT80 because the AT80 uses a much better, newer design and ED glass. Still, I had them all out and so compared them. The AT80 performed like it had more aperture than the Starbase 80. Not sure if this might be due to better coatings, baffling, more transparent glass or what, but the differences were unmistakable. There were many things I could see with the AT80 I couldn't even glimpse with the Starbase 80. I am scratching my head on this one. I thought maybe there might be some internal reflections or glare hurting image quality, but I have yet to find it. I think it's worth noting the AT80ED appears to be a much more transparent lens and shows noticeably more details and nebulosity than the Starbase 80.

 

All scopes were allowed to completely reach thermal equilibrium, the seeing out here on the coast for the last week has been absolutely exceptional, all scopes were in collimation (checked several times to make sure), and the same diagonal was used in all scopes. Eyepieces were the same where possible, but I did have to substitute different focal lengths of the same brand/design to get approximately the same magnifications across all scopes for comparing. The eyepieces are known quantities I have been using for years and feel comfortable those chosen were delivering the same quality of images across all three scopes.

 

It's a good, basic achromat in a gorgeous tube assembly. Unfortunately, most definitely not anything special. If you're looking for an exceptional achromatic doublet, you will do much better with a vintage refractor like a Royal Astro Optical, Unitron, etc. If you want something in a smaller package with better correction or a good scope for a beginner, then the AT72EDII or the AT80 are much better scopes. 

 

I will continue to test and use the Starbase 80 for a while, but it definitely isn't a keeper for me. Honestly, I am mildly disappointed. It's been fun to try though.

 

More later.


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#2 payner

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Posted 31 October 2019 - 06:38 PM

Enjoyed reading your comparison of these refractors and giving us your findings.


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#3 IMB

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Posted 31 October 2019 - 07:25 PM

Thank you very much for a thorough review.


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#4 aa6ww

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Posted 31 October 2019 - 07:30 PM

Thanks for the nice write up on the Starbase 80. I have a few questions regarding your comments.


Quote: CA was pronounced on Jupiter and Sirius and still pretty significant on Saturn and Vega. I don't mind CA to a certain extent, but I am very sensitive to it and this much color (the same as you will find in any decent 80mm f/10 to f/11 refractor) really kind of bugs me. I am used to my achromats being much slower and better corrected than this.


Question: What achromats specifically are you referring to which are slower and better corrected from this comment?



Quote: Handles magnification fairly well up to about 119x and then the images start to fall apart rapidly with increasing magnification. For an 80mm, this isn't too bad, almost 40x per inch which is pretty standard average for most inexpensive, mass produced telescopes.

Question: What objects are you observing where the image falls apart rapidly at 119x?



Quote: I compared it to a 76mm/1200 RAO (vintage achromat) and the AT80 (currently made ED apochromat) and both were very much superior to the Starbase in terms of optics, mechanics/tube assembly, and performance.

Question: What specifically makes your AT80 and 76mm/1200 RAO superior mechanically and have how are the tube assemblies superior to the Starbase 80?




Quote: The RAO had considerably better correction of SA, CA, etc. and delivers a textbook perfect star test. The RAO is also able to deliver sharper images up to much higher magnifications (I routinely use a 6mm for 200x on the moon and double stars with this) and it delivers higher contrast images.


Comments: I have an 80mm F/15, definitely agree on this, especially better contrast to shorter focal length refractors. I'm sure your 76 F/15 squashes your AT-80 in this regard also. I noticed you didn't mention that.



Quote: All scopes were allowed to completely reach thermal equilibrium, the seeing out here on the coast for the last week has been absolutely exceptional, all scopes were in collimation (checked several times to make sure), and the same diagonal was used in all scopes. Eyepieces were the same where possible, but I did have to substitute different focal lengths of the same brand/design to get approximately the same magnifications across all scopes for comparing. The eyepieces are known quantities I have been using for years and feel comfortable those chosen were delivering the same quality of images across all three scopes.

Question: Were these tests all side by side tests on the same night?


Quote: It's a good, basic achromat in a gorgeous tube assembly. Unfortunately, most definitely not anything special. If you're looking for an exceptional achromatic doublet, you will do much better with a vintage refractor like a Royal Astro Optical, Unitron, etc. If you want something in a smaller package with better correction or a good scope for a beginner, then the AT72EDII or the AT80 are much better scopes.


Comments: Not many people want an 75-80mm F/15 Achromat. I do, its the only Achromat I have, my 80mm F/15. It has a 2" focuser.
I had a beautiful Vixen 80mm F11 Custom I sold this year. I just had too many scopes and sold all my achromats for triplets and doublets. I regret selling my white tube Vixen, it was an exceptional Japaneese scope from the 1980's and had a 2" Focuser.

Thanks for the review. It still seems like an exceptional 80mm F/11 Achromat but they should sell it as an OTA only. I bet one wouldn't last a day if it came up for sale on CN. Fortunately, my AT-92 fills my needs for a scope of that size and makes for a very nice piggy back scope on my and C11 also. These are still small aperture scopes for plinkling. Nothing too serious but definitely lots of fun. I'm a big fan of small refractors under 4"

...Ralph

Edited by aa6ww, 31 October 2019 - 07:31 PM.

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#5 Redbetter

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Posted 01 November 2019 - 05:21 AM

 

CA was pronounced on Jupiter and Sirius and still pretty significant on Saturn and Vega. I don't mind CA to a certain extent, but I am very sensitive to it and this much color (the same as you will find in any decent 80mm f/10 to f/11 refractor) really kind of bugs me. I am used to my achromats being much slower and better corrected than this.

 

Handles magnification fairly well up to about 119x and then the images start to fall apart rapidly with increasing magnification. For an 80mm, this isn't too bad, almost 40x per inch which is pretty standard average for most inexpensive, mass produced telescopes.

 

 

Performance sounds similar to my garage sale Celestron LT 80AZ (f/11.3), but coming from the opposite direction as to expectations and price:  at $10 it was too cheap to pass up...even though there was water dripping from the open diagonal when I saw it and the focuser rack had some issues and lacked an acceptable RDF.  When I tested the objective at night I was surprised that it was sharper than I expected from a modern beginner's achro, which led me to put a real focuser (2") on it and rebalance it with a long dovetail closer to the focuser.

 

I am not surprised by the level of color with the Starbase 80, as in general it should be slightly greater at f/10 than an 80 at f/11.3.  The 119x figure is roughly the same as the 129x that seems to be about the limit for planetary detail with my 80 f/11.3.  (Perhaps the same effective increment because available eyepiece focal lengths tend to dictate this.)  I have tried filtering etc...but still see the same sort of planetary resolution limit, so it doesn't appear to be the wide spread blue/violet that is the issue so much as the residual spread in the medium wavelengths.  It isn't the color/halo that I object to as I quickly mentally "filter it out" (although it does affect and skew the impression of color on the bodies themselves); it is the loss of fine detail that comes with it and seems to linger even after the blue/violet halo is eliminated.

 

I find it interesting comparing the progression of CA in 80's at f/5, f/11.3 and an ED doublet, and the impact this has on being able to resolve planets (Neptune & Uranus), features and transits on Jupiter, double stars, etc.  The progression of maximum effective planetary magnifications has been straightforward and as one would expect.    

 

Question 1:  What diagonal do they include?  I am guessing it is not the standard 1.25" Tak prism.

 

Question 2:  Follow up...if not, is the diagonal well collimated?

 

Question 3:  How is the mount for the scope?


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#6 SandyHouTex

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Posted 01 November 2019 - 05:20 PM

Brief rundown, more in-depth review to follow with all of the juicy details and photos.

 

Recently received the Takahashi Starbase 80mm f/10 achromatic refractor on alt-az mount. Wonderful fit and finish and pretty good optics. If you have used a Vixen 80mm f/11 refractor made in Japan whether badged as a Celestron Meade, Vixen, etc. then you already know how this will perform. The Starbase 80 is basically like these, but slightly faster and with a smidgen more chromatic aberration. 

 

Star test was good, but no where near as good as what one finds with the regular Takahashi apochromatic refractors and old fashioned long focal length achromats (like those from RAO, etc.) Did notice scattered light at medium to higher magnifications, but couldn't find any sources of glare or reflections inside the tube assembly (it's a well-made unit). Not sure if this is because of rough optical surfaces or something inside the tube assembly I can fix with flocking or flat black paint.

 

CA was pronounced on Jupiter and Sirius and still pretty significant on Saturn and Vega. I don't mind CA to a certain extent, but I am very sensitive to it and this much color (the same as you will find in any decent 80mm f/10 to f/11 refractor) really kind of bugs me. I am used to my achromats being much slower and better corrected than this.

 

Handles magnification fairly well up to about 119x and then the images start to fall apart rapidly with increasing magnification. For an 80mm, this isn't too bad, almost 40x per inch which is pretty standard average for most inexpensive, mass produced telescopes.

 

I compared it to a 76mm/1200 RAO (vintage achromat) and the AT80 (currently made ED apochromat) and both were very much superior to the Starbase in terms of optics, mechanics/tube assembly, and performance.

 

The RAO had considerably better correction of SA, CA, etc. and delivers a textbook perfect star test. The RAO is also able to deliver sharper images up to much higher magnifications (I routinely use a 6mm for 200x on the moon and double stars with this) and it delivers higher contrast images.

 

The AT80ED is a marvel - superb color correction, short/fast tube assembly with buttery smooth 2" focuser, solid tube assembly construction, and a very nice lens. It's unfair to compare the Starbase to the AT80 because the AT80 uses a much better, newer design and ED glass. Still, I had them all out and so compared them. The AT80 performed like it had more aperture than the Starbase 80. Not sure if this might be due to better coatings, baffling, more transparent glass or what, but the differences were unmistakable. There were many things I could see with the AT80 I couldn't even glimpse with the Starbase 80. I am scratching my head on this one. I thought maybe there might be some internal reflections or glare hurting image quality, but I have yet to find it. I think it's worth noting the AT80ED appears to be a much more transparent lens and shows noticeably more details and nebulosity than the Starbase 80.

 

All scopes were allowed to completely reach thermal equilibrium, the seeing out here on the coast for the last week has been absolutely exceptional, all scopes were in collimation (checked several times to make sure), and the same diagonal was used in all scopes. Eyepieces were the same where possible, but I did have to substitute different focal lengths of the same brand/design to get approximately the same magnifications across all scopes for comparing. The eyepieces are known quantities I have been using for years and feel comfortable those chosen were delivering the same quality of images across all three scopes.

 

It's a good, basic achromat in a gorgeous tube assembly. Unfortunately, most definitely not anything special. If you're looking for an exceptional achromatic doublet, you will do much better with a vintage refractor like a Royal Astro Optical, Unitron, etc. If you want something in a smaller package with better correction or a good scope for a beginner, then the AT72EDII or the AT80 are much better scopes. 

 

I will continue to test and use the Starbase 80 for a while, but it definitely isn't a keeper for me. Honestly, I am mildly disappointed. It's been fun to try though.

 

More later.

That’s odd.  I see no CA on Saturn using the Starbase Orthos.  I expected to see it on Jupiter, Sirius, and Vega considering how bright they are.  It’s also important to note that the CA in the Starbase, is the same level of CA as in my 80mm f/6.25 EON that is an FPL-53 doublet, which is the equivalent of a fluorite doublet.  My Starbase handles 133X with the supplied 6mm Ortho with no trouble.   Very sharp.  It also has a near perfect star test in and outside focus.  Just a small hint of violet out of focus, which is to be expected.


Edited by SandyHouTex, 01 November 2019 - 05:29 PM.

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#7 agmoonsolns

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Posted 01 November 2019 - 05:27 PM

The Starbase Orthos are not made in Japan, they are made in China (report on these to follow). Everyone is different in their sensitivity to chromatic aberration and sharpness. I am very sensitive to both. I was deliberately trying to be as picky as possible because people want to hear the details. Even if the differences are small, people want to know and that's what I have tried to do.

 

I will try to answer everyone's questions this weekend.

 

That’s odd.  I see no CA on Saturn using the Starbase Orthos.  I expected to see it on Jupiter, Sirius, and Vega considering how bright they are.  It’s also important to note that the CA in the Starbase, is the same level of CA as in my 80mm f/6.25 EON that is an FPL-53 doublet, which is the equivalent of a fluorite doublet.  My Starbase handles 133X with the supplied 6mm Ortho with no trouble.   Very sharp.


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#8 agmoonsolns

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Posted 01 November 2019 - 05:36 PM

Great, now we have provided people with a balanced array of user feedback on this scope. The more people do this, the better. I look forward to reading about other user experiences with the Starbase 80.

 

That’s odd.  I see no CA on Saturn using the Starbase Orthos.  I expected to see it on Jupiter, Sirius, and Vega considering how bright they are.  It’s also important to note that the CA in the Starbase, is the same level of CA as in my 80mm f/6.25 EON that is an FPL-53 doublet, which is the equivalent of a fluorite doublet.  My Starbase handles 133X with the supplied 6mm Ortho with no trouble.   Very sharp.  It also has a near perfect star test in and outside focus.  Just a small hint of violet out of focus, which is to be expected.


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#9 eros312

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Posted 01 November 2019 - 06:25 PM

The Starbase Orthos are not made in Japan, they are made in China 

See here https://scopetown.co...08449/list.html They are Japanese made. 


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#10 agmoonsolns

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Posted 01 November 2019 - 06:50 PM

They might be assembled in Japan, but I was told the optics are made in China. I'll provide a copy of the e-mail with my full review as I don't have much time right now.


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#11 agmoonsolns

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Posted 01 November 2019 - 07:07 PM

I was told the optics for the eyepieces were made in China, but I'll leave it up to others to investigate what was made where and by whom and where things were assembled. I don't want to get caught in the middle of a debate where one person says one thing and another says something entirely different.  It shouldn't matter where they were made or assembled, only how they compare with other similar eyepieces. I'll provide the information I have and stick to comparing the Starbase 80 equipment with equipment I have on hand and sharing the results. 

 

I am also more than willing to meet up with people locally and let them look through this equipment  for themselves to formulate their own opinions. As I said before, the more opinions and feedback we can get on things, the better.



#12 eros312

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Posted 01 November 2019 - 07:18 PM

I agree. I wasn't trying to cause any problems,  and I look forward to your continuing report. 


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#13 Redbetter

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Posted 01 November 2019 - 08:16 PM

That’s odd.  I see no CA on Saturn using the Starbase Orthos.  I expected to see it on Jupiter, Sirius, and Vega considering how bright they are.  It’s also important to note that the CA in the Starbase, is the same level of CA as in my 80mm f/6.25 EON that is an FPL-53 doublet, which is the equivalent of a fluorite doublet.  My Starbase handles 133X with the supplied 6mm Ortho with no trouble.   Very sharp.  It also has a near perfect star test in and outside focus.  Just a small hint of violet out of focus, which is to be expected.

An 80 f/10 achro should have over twice as much color blur as an 80 f/6.25 FPL-53 doublet, which has me wondering about the quality of correction of that particular EON sample.   I would expect the EON to show some color with that short of a ratio at 80mm, but to be matched by an f/10 achro of the same aperture suggests a problem.   The EON should be similar in color spot size to my 110 f/7 ED doublet w/ FPL-51, but the 110 should show color far more readily because it is almost twice as bright.  The 80 f/11.3 I have, has noticeably more color although the image is dimmer as noted.

 

Blue color blur with Saturn is more muted because of its lower surface brightness and golden hue, both of which reduce the relative intensity of the halo, and the latter of which also reduces the relative intensity to the planet's own.  Even so, I can see it with an achro or a more semi-apo ED.


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#14 Bomber Bob

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Posted 01 November 2019 - 09:38 PM

An 80 f/10 achro should have over twice as much color blur as an 80 f/6.25 FPL-53 doublet, which has me wondering about the quality of correction of that particular EON sample.

 

I briefly owned a Meade S5000 80mm F6 triplet (replaced by my FL80S), and its color correction was near-perfect. I've tested some very well made vintage Astro Optical (Japan) 76mm F12 achromatics, and even those would show false color -- how much I saw with Saturn depended on seeing, sky-glow, accessories, etc.  Not sure how the S5000 would compare with the EON, but I would expect the EON to be a noticeable improvement over the SB80, though I think this new Tak-offered refractor to be well made, too.


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#15 SandyHouTex

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Posted 01 November 2019 - 10:34 PM

An 80 f/10 achro should have over twice as much color blur as an 80 f/6.25 FPL-53 doublet, which has me wondering about the quality of correction of that particular EON sample.   I would expect the EON to show some color with that short of a ratio at 80mm, but to be matched by an f/10 achro of the same aperture suggests a problem.   The EON should be similar in color spot size to my 110 f/7 ED doublet w/ FPL-51, but the 110 should show color far more readily because it is almost twice as bright.  The 80 f/11.3 I have, has noticeably more color although the image is dimmer as noted.

 

Blue color blur with Saturn is more muted because of its lower surface brightness and golden hue, both of which reduce the relative intensity of the halo, and the latter of which also reduces the relative intensity to the planet's own.  Even so, I can see it with an achro or a more semi-apo ED.

My EON 80 is a great, very sharp scope.  The fact that Venus, Jupiter, Sirius, and Vega show some slight color is not a defect.  One of the knocks on many short APOs, for example the Tak Sky 90, was and is that you can’t correct out the CA at those short focal lengths.  In fact, if you look at the ray traces in “Telescope Optics”, by Rutten and van Venrooij, Figure 6.19, even an f/8 fluorite APO doublet (think Tak FS series), has a red blur circle twice the Airy disk, and a blue blur circle that is three times the Airy disk at best focus.


Edited by SandyHouTex, 01 November 2019 - 10:38 PM.


#16 SandyHouTex

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Posted 01 November 2019 - 10:36 PM

I was told the optics for the eyepieces were made in China, but I'll leave it up to others to investigate what was made where and by whom and where things were assembled. I don't want to get caught in the middle of a debate where one person says one thing and another says something entirely different.  It shouldn't matter where they were made or assembled, only how they compare with other similar eyepieces. I'll provide the information I have and stick to comparing the Starbase 80 equipment with equipment I have on hand and sharing the results. 

 

I am also more than willing to meet up with people locally and let them look through this equipment  for themselves to formulate their own opinions. As I said before, the more opinions and feedback we can get on things, the better.

Actually I did check with Takahashi America and the Starbase 80 Orthos and Kellners are made in Japan.  Just like the scope.

 

What happened to the email you said you had?


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#17 agmoonsolns

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Posted 01 November 2019 - 10:39 PM

"I'll provide a copy of the e-mail with my full review as I don't have much time right now."

 

Actually I did check with Takahashi America and the Starbase 80 Orthos and Kellners are made in Japan.  Just like the scope.

 

What happened to the email you said you had?


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#18 Redbetter

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Posted 02 November 2019 - 02:12 AM

My EON 80 is a great, very sharp scope.  The fact that Venus, Jupiter, Sirius, and Vega show some slight color is not a defect.  One of the knocks on many short APOs, for example the Tak Sky 90, was and is that you can’t correct out the CA at those short focal lengths.  In fact, if you look at the ray traces in “Telescope Optics”, by Rutten and van Venrooij, Figure 6.19, even an f/8 fluorite APO doublet (think Tak FS series), has a red blur circle twice the Airy disk, and a blue blur circle that is three times the Airy disk at best focus.

The problem is that something doesn't add up in your comparison of the level of CA in the Starbase and the EON.  If they are equal in color correction, then the EON is underperforming by a considerable margin.  After all, there is only so perfect the 80 f/10 achro could be.  If we were talking about an f/15 or greater 80 achro, then closer CA performance would be expected. 

 

The fact that color is showing on Jupiter is not so much a defect as expected for the EON combination ratio/aperture/FPL-53 doublet.   It is the Starbase matching it (from what you are saying) that suggests it is underperforming its potential. 


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#19 Delta608

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Posted 02 November 2019 - 06:56 AM

"I'll provide a copy of the e-mail with my full review as I don't have much time right now."

 

   Years ago when the movie 300 came out there was a written review of the movie...There was one fella who had challenged the reviewer with..."The Spartan's  scarlet capes in the movie were too dark according to history.

 

Take it for what its worth and thanks for your review...


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#20 lylver

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Posted 03 November 2019 - 01:22 AM

/.../

Star test was good, but no where near as good as what one finds with the regular Takahashi apochromatic refractors and old fashioned long focal length achromats (like those from RAO, etc.) Did notice scattered light at medium to higher magnifications, but couldn't find any sources of glare or reflections inside the tube assembly (it's a well-made unit). Not sure if this is because of rough optical surfaces or something inside the tube assembly I can fix with flocking or flat black paint.


I compared it to a 76mm/1200 RAO (vintage achromat) and the AT80 (currently made ED apochromat) and both were very much superior to the Starbase in terms of optics, mechanics/tube assembly, and performance.

 

The RAO had considerably better correction of SA, CA, etc. and delivers a textbook perfect star test. The RAO is also able to deliver sharper images up to much higher magnifications (I routinely use a 6mm for 200x on the moon and double stars with this) and it delivers higher contrast images.

 

/.../

How do you define scatter in you visual test ?

How do you mesure SA (spherical aberration) in star test ?

 

If there is scatter on this objective is due to roughness it may be defective : it is soft polished at Kubota Optical

see the blog, a visit by Scopetech that has the same manufacturer : https://blogs.yahoo....o/32155110.html

 

KO_0.jpg

 

Spherical Aberration is low on a 80mm f/10 BK7 F2 classic objective, it is hard to see better than lambda/10

On F ray theoric value grows to lambda/9 outside .35 degree off axis, small to invisible in center.

=> figuring/polishing is the limit in this case.

It start only to be cared since 4 inch diameter.

 

Anyway, about the origin of the refractor manufacturing, Scopetech proposed the textbook design for the STL80A-L (80/1000), correction between Sidgwick that is the minimum to be used in perfect atmosphere and Conrady criteria that is very resilient. The starbase 80 is at Sidgwick limit, this is a beginner scope. Previously sold in the 1980th and still now similar design were more robust for this like the entry level Vixen 80/910.

 

In fact, I believe SA residual could come from the eyepiece used at f/10.

But we need to know which eyepiece you used.

 

Also this need to be confirmed : the objective as a small air-spaced gap and is only "pink" mono layer coated.

Contrast at high magnification is better with classic gap 1/1000th fl. or a 4 layer modern one that Kubota proposed as a standard for the 80/1200.

 

The more polishing precision you offer, the more you must look at design and AR treatment you use.

Despite the price, this is a beginner unspecialised scope that should last long and reliable.



#21 SandyHouTex

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Posted 03 November 2019 - 06:05 PM

How do you define scatter in you visual test ?

How do you mesure SA (spherical aberration) in star test ?

 

If there is scatter on this objective is due to roughness it may be defective : it is soft polished at Kubota Optical

see the blog, a visit by Scopetech that has the same manufacturer : https://blogs.yahoo....o/32155110.html

 

attachicon.gif KO_0.jpg

 

Spherical Aberration is low on a 80mm f/10 BK7 F2 classic objective, it is hard to see better than lambda/10

On F ray theoric value grows to lambda/9 outside .35 degree off axis, small to invisible in center.

=> figuring/polishing is the limit in this case.

It start only to be cared since 4 inch diameter.

 

Anyway, about the origin of the refractor manufacturing, Scopetech proposed the textbook design for the STL80A-L (80/1000), correction between Sidgwick that is the minimum to be used in perfect atmosphere and Conrady criteria that is very resilient. The starbase 80 is at Sidgwick limit, this is a beginner scope. Previously sold in the 1980th and still now similar design were more robust for this like the entry level Vixen 80/910.

 

In fact, I believe SA residual could come from the eyepiece used at f/10.

But we need to know which eyepiece you used.

 

Also this need to be confirmed : the objective as a small air-spaced gap and is only "pink" mono layer coated.

Contrast at high magnification is better with classic gap 1/1000th fl. or a 4 layer modern one that Kubota proposed as a standard for the 80/1200.

 

The more polishing precision you offer, the more you must look at design and AR treatment you use.

Despite the price, this is a beginner unspecialised scope that should last long and reliable.

I clicked on the link and read that this factory also grinds and polishes APOs and Fluorite objectives.  Very nice.



#22 aa6ww

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Posted 03 November 2019 - 07:23 PM

Waiting for some answers to the questions I asked, since the weekend is over. Why do I suspect there wont be any specific response to any of my questions asked......???

 

...Ralph

 

 

The Starbase Orthos are not made in Japan, they are made in China (report on these to follow). Everyone is different in their sensitivity to chromatic aberration and sharpness. I am very sensitive to both. I was deliberately trying to be as picky as possible because people want to hear the details. Even if the differences are small, people want to know and that's what I have tried to do.

 

I will try to answer everyone's questions this weekend.


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#23 agmoonsolns

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Posted 03 November 2019 - 08:10 PM

"aa6ww has just posted a reply to a topic that you have subscribed to titled "Takahashi Starbase 80 - My User Notes".
This review is sounding more and more flakey everytime i read and reread this review. Do we already have Starbase haters out here.
I no longer take this review as anything but some type of low level bashing.  There are too too many holes in this review.

FAKE!

...Ralph"

 

Are you kidding me? I said it's a basically good scope, it just simply isn't the miracle worker some claim it is. It's a good, mass-produced 80mm f/10 achromat. It shows about as much chromatic aberration as the very good Vixen 80mm f/11 achromats which is a positive as those are good scopes.

 

I don't "hate" Takahashi telescopes, I am a huge fan with a house full of them (along with many other telescopes) and a fortune invested in their equipment. I also have over half a century of experience. No wonder people don't want to post equipment reviews. Good grief, who wants to deal with this kind of nonsense?

 

I most definitely did not bash it, I have been providing honest details on what I actually saw. I have even taken pictures to show what I am seeing. If you don't like the results, that isn't my fault and it most certainly isn't a reason to attack the reviewer. I so firmly stand behind what I said, I have offered to meet with people to show them the views through these scopes so they can judge for themselves.

 

This is a very nice, but very average telescope. I am so sorry if people don't like this and choose to react by attacking the reviewer. You didn't even wait to read the full review, you just jumped all over me and engaged in brutal name-calling. I am so done with dealing with this kind of behavior, it's inexcusable.


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#24 agmoonsolns

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Posted 03 November 2019 - 08:26 PM

Ralph, instead of attacking people for saying something you didn't like, why don't you go buy a Starbase 80 yourself? After you see it performs exactly as I said, you can post an apology. 


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#25 agmoonsolns

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Posted 03 November 2019 - 08:46 PM

And I am waiting for your sincere apology. It looks like we are both going to have to live with disappointment. There's absolutely no way in heaven or hell I will ever read or respond to any of your questions or posts again. Please take this opportunity to go take a flying jump in the lake.

 

Waiting for some answers to the questions I asked, since the weekend is over. Why do I suspect there wont be any specific response to any of my questions asked......???

 

...Ralph


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