73 replies to this topic

[Scott in NC]

I found another excellent sample of a TOA-130 to test, and this one appears to have been from the same run as the last one that I tested, with serial numbers differing by only 16 between the two.  I have not had a chance to test it out under the stars, and I'm waiting for the weather to cooperate. 

For those of you who aren't familiar with the particulars of the TOA-130, this is a 130mm f/7.7 (FL 1000mm) apochromatic triplet with a robust lens cell encasing two FPL-53 elements, with two wide air gaps between the FPL-53 elements and the mating element. Just like the last one that I tested, this is the NS version with a 2.7" focuser.  Takahashi also produces a NFB version which is optically equivalent but has a 4" focuser. 

Here's the scope set up on my optical testing bench, a.k.a, dining room table

 

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[Scott in NC]

Green inside / outside focus:

 

 

Red inside / outside focus:

 

 

Blue inside / outside focus:

 

 

White inside / at / outside focus:

 

 

 

[Scott in NC]

This looks very nice.  Although the two are very close, and I'm undoubtedly splitting hairs by saying so, I think I might like this one even better than the last one that I tested.  Having said that, the last one gives views (for visual observation at least) that are near perfection, as would be expected from a high-end apo triplet. That one is so close to perfection that I can't imagine that I'd see a noticeable difference between the two. Maybe one of these days the skies will cooperate so I can test out that theory.

[CHASLX200]

This looks very nice.  Although the two are very close, and I'm undoubtedly splitting hairs by saying so, I think I might like this even better than the last one that I tested.  Having said that, the last one gives views (for visual observation at least) that are near perfection, as would be expected from a high-end apo triplet. That one is so close to perfection that I can't imagine that I'd see a noticeable difference between the two. Maybe one of these days the skies will cooperate so I can test out that theory.

I am sure it would pass my sniff test.

[scoale]

Superlative.  What I would have expected, but still impressive.  I continue to believe the TOA-130 sets the optical standard for 5" refractors.

[CHASLX200]

Superlative.  What I would have expected, but still impressive.  I continue to believe the TOA-130 sets the optical standard for 5" refractors.

For the price it should.

[Aibrahim]

Man, would love to put my TOA 150,130 and SVX152T to test. I have a ronchi screen that is on a 1"X1" glass but don't know how to construct the rest of ronchi tube + camera attachment.

[Scott in NC]

Man, would love to put my TOA 150,130 and SVX152T to test. I have a ronchi screen that is on a 1"X1" glass but don't know how to construct the rest of ronchi tube + camera attachment.

If you have access to a 3D printer, the files are located here, courtesy of fellow CN member moshen: https://www.thingive.../thing:2904804 

[Scott in NC]

If you have access to a 3D printer, the files are located here, courtesy of fellow CN member moshen: https://www.thingive.../thing:2904804 

I don’t know why that link doesn’t work. But if you use the search terms “moshen Ronchi” you’ll find it.

[Aibrahim]

I don’t know why that link doesn’t work. But if you use the search terms “moshen Ronchi” you’ll find it.

Much appreciated. So if I take that to a 3D printing shop or buy a 3D printing I'll be able to print the whole assembly? Minus the optical flat?

[Lagrange]

The null image looks really smooth. Is that indicative of the figure and polish being very good?

[Aibrahim]

The null image looks really smooth. Is that indicative of the figure and polish being very good?

Looks absolutely superb in my humble opinion

[Scott in NC]

Much appreciated. So if I take that to a 3D printing shop or buy a 3D printing I'll be able to print the whole assembly? Minus the optical flat?

You should be able to. I don’t know much about 3D printing but my son is pretty well versed in it and used that file to print one for me. He might have modified it a little though.

[Scott in NC]

The null image looks really smooth. Is that indicative of the figure and polish being very good?

Yes, indeed.

[Scott in NC]

Much appreciated. So if I take that to a 3D printing shop or buy a 3D printing I'll be able to print the whole assembly? Minus the optical flat?

And I forgot to mention, but you probably already knew this—you’ll need to get some LED lights. Green would be the minimum you’ll want, but having red, blue, and white would be nice too. I’m not really sure what the best source is though, as I got mine from a fellow CN’er.  You’ll also need a power source (mine uses two AAA batteries) for the light, and having a rheostat to allow you to adjust the brightness is nice to have too.

[Aibrahim]

And I forgot to mention, but you probably already knew this—you’ll need to get some LED lights. Green would be the minimum you’ll want, but having red, blue, and white would be nice too. I’m not really sure what the best source is though, as I got mine from a fellow CN’er. You’ll also need a power source (mine uses two AAA batteries) for the light, and having a rheostat to allow you to adjust the brightness is nice to have too.

Thank you. I got that covered ( the led source and power ) My biggest two issues now is the optical flat which I'm thinking of using oil pan for starters instead and the assembly of the Ronchi screen inside a 2 inch barrel with the integration of camera threads into it and led lights. How am I supposed to fit that 1"x1" Ronchi screen inside a 2 inch barrel and make room for the interchangeable led and attaching the camera to the end of it might be the death of this project.

[davidc135]

Green inside / outside focus:

 

IMG_9255 bright green inside.JPG

IMG_9258 bright green outside.JPG

 

Red inside / outside focus:

 

IMG_9255 bright red inside.JPG

IMG_9258 bright red outside.JPG

 

Blue inside / outside focus:

 

IMG_9255 bright blue inside.JPG

IMG_9258 bright blue outside.JPG

 

White inside / at / outside focus:

 

IMG_9255 bright.JPG

IMG_9257 bright.JPG

IMG_9258 bright.JPG

Superb lens. What's especially impressive is their control of sphero-chromatism.   David

[Scott in NC]

Thank you. I got that covered ( the led source and power ) My biggest two issues now is the optical flat which I'm thinking of using oil pan for starters instead and the assembly of the Ronchi screen inside a 2 inch barrel with the integration of camera threads into it and led lights. How am I supposed to fit that 1"x1" Ronchi screen inside a 2 inch barrel and make room for the interchangeable led and attaching the camera to the end of it might be the death of this project.

Yeah, I think you might need a larger Ronchi screen, and unfortunately I don’t have a good source for that.

[bobhen]

One of Takahashi's secrets, besides getting the lenses from Canon/Optron, is keeping the focal length very reasonable. The TOA 130 is F7.7, which is slowish for an apo triplet. The TSA 120 is F7.5 and the TSA 102 was F8. For example, Astro-Physics pushes their triplet design much faster, usually in the F6 range, probably for the imaging crowd. 

 

Tak's astrographs are faster but they have even more lens elements.

 

Bob

[Jeff B]

This looks very nice.  Although the two are very close, and I'm undoubtedly splitting hairs by saying so, I think I might like this one even better than the last one that I tested.  Having said that, the last one gives views (for visual observation at least) that are near perfection, as would be expected from a high-end apo triplet. That one is so close to perfection that I can't imagine that I'd see a noticeable difference between the two. Maybe one of these days the skies will cooperate so I can test out that theory.

A more perfect-perfect.

 

Hey, splitting angel hairs is what we do here on CNs Scott.   

 

Well done and suuuuuupeeeeeer smooth.  

 

I see you are having fun!

 

Jeff

[Scott in NC]

Jeff, I photographed the “at focus” image (what other others might call the “null” image, but I think that that might be an inaccurate use of the term) multiple times in order to best show any surface irregularities. I tried numerous times and failed, as that was the ugliest image I was able to capture. I like it when that happens!

[CHASLX200]

Jupiter should snap with life in my seeing at 300x.

[peleuba]

Superb lens. What's especially impressive is their control of sphero-chromatism.   David

 

Yes.  Its a novel design using two pieces of FPL53, a VERY wide air gap and a relaxed focal ratio.  The TOA130 is the most color free scope I have ever looked through.

 

bobhen a few posts up nailed it.         

 

There is a slight rolled edge... I would have to star test the scope to see how much of an impact it would have at the eyepiece.  It may very well be inconsequential.

Edited by peleuba, 25 May 2024 - 08:44 PM.

[Scott in NC]

I star tested the scope on Arcturus last night (I know that a colored star isn’t the best choice to test for chromatism, but that was about the only star visible), and I didn’t see any issues.  Compare this with the last TOA-130 that I tested, which looks very similar on DPAC testing, and also looks great under the stars:

 

https://www.cloudyni...0ns/?p=13152814

[Jeff B]

Jeff, I photographed the “at focus” image (what other others might call the “null” image, but I think that that might be an inaccurate use of the term) multiple times in order to best show any surface irregularities. I tried numerous times and failed, as that was the ugliest image I was able to capture. I like it when that happens!

Me too!  I have a couple of scopes that were "frustrating" in that regard.  I just could not get an ugly looking image at focus no matter how many adjustments I did, including hyping the contrast during processing.

 

So annoying!