1482 replies to this topic

[alnitak22]

Here:

https://web.archive....t_oculaires.pdf
https://web.archive....laires_10mm.pdf

Thanks!

[Mike B]

The TPLs are 4-element, not 5-element.

I beg your pardon- so many similarities with the TPL in my mind, I’d talked myself into a 5th element  

 

To refresh re: the data from that initial TPL thread:

 

 

Main specifications
TPL-12.5
Focal length: 12.5mm
Eye relief: 9mm
Apparent field of view: 48°
Lens construction: 4 elements in 2 groups
Size: φ39 x 51mm
Weight: 90g
TPL-18
Focal length: 18mm
Eye relief: 13mm
Apparent field of view: 48°
Lens construction: 4 elements in 2 groups
Size: φ39×60mm
Weight: 110g
TPL-25
Focal length: 25mm
Eye relief: 18mm
Apparent field of view; 48°
Lens construction: 4 elements in 2 groups
Size: φ39×71mm
Mass: 140g

[PatientObserver]

Can we please keep discussions in this thread limited to TPL reports, rather then unrelated criticism or defenses of other manufacturers? There is plenty of said discussion in the other thread; this one was created so reports of the TPL line would be easier to find. I am not referring to comparisons and observations between eyepieces in the reports.

I have now had the opportunity to use my TPLs in my Mewlon 180C for brief observations over a period of three nights. The scope is still new to me, and I have yet to compare the view of the TPL to that of the Pentax XW in the Mewlon. What I can say is that the lunar views I have seen with the TPL in the Mewlon are clear and sharp, and are the best I have seen yet. The Pentax XW in the FOA-60Q are similarly excellent, just not as bright (which is what I would expect given the difference in aperture). I find that I have more blackouts while approaching the eyepieces with the TPL than the Pentax XW, but it is not distracting to me, and is not an issue once I find the correct placement.

I compared similar magnifications between the two scopes:

FOA-60Q | Magnification | Mewlon 180C | Magnification
Pentax XW 10 | 90.1 | TPL 25 | 86.4
Pentax XW 7 | 128.7 | TPL 18 | 120
Pentax XW 5 | 180.2 | TPL 12.5 | 172.8

Note: My scopes are not aligned, so I had to realign to my target whenever I switched between scopes. That said, there were no details that I could see in one scope that I could not see in the other. Again, the only difference was brightness.

Edited by PatientObserver, 28 September 2023 - 06:51 AM.

[Mike B]

 

Can we please keep discussions in this thread limited to TPL reports, rather then unrelated criticism or defenses of other manufacturers? There is plenty of said discussion in the other thread; this one was created so reports of the TPL line would be easier to find. I am not referring to comparisons and observations between eyepieces in the reports.

Sorry to disappoint, but how the TPL plays-out with other gear, like amplifiers and scopes of various apertures, types, & f/ratios is highly pertinent! I’m grateful to all those who’ve posted herein 

 

Plus, comparing the TPL to other oculars is valuable for establishing a familiar frame-of-reference for our fellow observers, and honestly, is the primary tool most of us have handy for offering one another a useful data-point.

 

Seems to this gearhead this thread re-boot has been right on target! And just such threads in the archives of CN & other sites have been extraordinarily useful in my past digs for info! 

[PatientObserver]

Sorry to disappoint, but how the TPL plays-out with other gear, like amplifiers and scopes of various apertures, types, & f/ratios is highly pertinent! I’m grateful to all those who’ve posted herein

Plus, comparing the TPL to other oculars is valuable for establishing a familiar frame-of-reference for our fellow observers, and honestly, is the primary tool most of us have handy for offering one another a useful data-point.

Seems to this gearhead this thread re-boot has been right on target! And just such threads in the archives of CN & other sites have been extraordinarily useful in my past digs for info!

Comparing them to other eyepieces and discussing how it works with other gear is encouraged and I stated so in my previous post. What I am complaining about is how the thread deviated into discussions about Tele Vue that had nothing/little to do with the TPL.

[SandyHouTex]

Here:

https://web.archive....t_oculaires.pdf
https://web.archive....laires_10mm.pdf

So I looked at both of those, but since I can't read French, I mostly looked at the pictures.  It looks like they just checked things like chromaticism, figure, and things like that.  I see nothing on quality of polish.

[SandyHouTex]

Sorry to disappoint, but how the TPL plays-out with other gear, like amplifiers and scopes of various apertures, types, & f/ratios is highly pertinent! I’m grateful to all those who’ve posted herein 

 

Plus, comparing the TPL to other oculars is valuable for establishing a familiar frame-of-reference for our fellow observers, and honestly, is the primary tool most of us have handy for offering one another a useful data-point.

 

Seems to this gearhead this thread re-boot has been right on target! And just such threads in the archives of CN & other sites have been extraordinarily useful in my past digs for info! 

I tend to agree, but we certainly don't need posts about how wonderful TV eyepieces with NO data.

Edited by SandyHouTex, 28 September 2023 - 11:36 AM.

[Starman1]

So I looked at both of those, but since I can't read French, I mostly looked at the pictures.  It looks like they just checked things like chromaticism, figure, and things like that.  I see nothing on quality of polish.

Use Google Translate to read sections, then.

Note that the data is at f/3.5 and f/7.

Polish information is going to be proprietary for all manufacturers.

The only way to get official data on that is to dismantle an eyepiece and test using a microscope.

That is NEVER going to be done.

The best we're going to get will be interferograms of surfaces or wavefront measurements.

When we're lucky, we'll see the Lyot test results, the most illustrative test for surface polish.

[Mike B]

 

…. Polish information is going to be proprietary for all manufacturers.….

That makes sense- like McD’s “secret sauce” recipe, or CocaCola’s, or any of a thousand famous marketing details- kept under lock & key.

 

Now, I’m curious, if Orion or APM, etc. we’re to approach an “offshore” EP manuf., wanting 5,000 units of XYZ EP design made to their specs- do they simply click boxes on a pre-cooked drive-thru menu board? Would surface polish even be on such a menu? Who is it that makes such a choice?… and where in the pipeline is it made?

[Starman1]

That makes sense- like McD’s “secret sauce” recipe, or CocaCola’s, or any of a thousand famous marketing details- kept under lock & key.

 

Now, I’m curious, if Orion or APM, etc. we’re to approach an “offshore” EP manuf., wanting 5,000 units of XYZ EP design made to their specs- do they simply click boxes on a pre-cooked drive-thru menu board? Would surface polish even be on such a menu? Who is it that makes such a choice?… and where in the pipeline is it made?

If it is a previously existing product, and this seems to be the case with Orion's eyepiece offerings, they would specify packaging, name and logo on the product, perhaps anodized color, rubber eyecup type,

possibly filter threading.  Polish, lens coatings, focal length choices likely would not be selectable.  It would cost WAY too much extra.

For 5000 of each focal length, the factory might offer additional options.  Even an order for 5000 pieces in total would be large enough for some possible extra options.

 

The serious question is whether any factory would produce something entirely new for an order of that size.

Maybe yes, if the factory sees a future market private-labeling the product for others.  Maybe no if it is a one-of-a-kind order, but that would totally depend on price.

[CrazyPanda]

Had extremely good seeing this morning. Did some more Jupiter testing at full aperture and with 130mm aperture mask, bringing the scope to F/13.2.

 

Pretty much same observations as before.

 

With the 130mm aperture mask, again, the TPL was brighter than the Docter or DeLite. Seems to confirm the initial observation with the 90mm ETX - when you're starved for light, you notice the brightness advantage of the TPL a bit more.

 

Sharpness and detail was the same in all three eyepieces, however, the lower scatter and extra brightness of the TPL did make features stand out more clearly in the TPL vs the Docter ever so slightly. I saw no noticeable advantage over the DeLite.

 

For fun I also tried the 28mm RKE with the Baader Hyperion Zoom 2.25x barlow (the barlow is telecentric in design so it should be 12.5mm effective focal length). Surprisingly, this combo had lower scatter than the TPL! However, eye positioning was so tricky due to the long eye relief, it was even less comfortable to try and that critical focus view of Jupiter with this combo than the TPL, so I abandoned it quickly. Maybe someday I'll fashion an eye guard to help with registration of the 28 RKE, but that oddball combination has some real potential.

 

At any rate, seeing was so good it was stupid to waste it comparing these eyepieces. Switched to the 6 Ethos which is every bit as sharp and contrasty as any "planetary" eyepiece, and at 330x, the view was incredible.

 

Also decided to do some imaging to take advantage of the seeing.

 

Edited by CrazyPanda, 28 September 2023 - 02:28 PM.

[Heitman]

Very nice!

[alnitak22]

Fabulous image, Crazy!

[25585]

Use Google Translate to read sections, then.

Note that the data is at f/3.5 and f/7.

Polish information is going to be proprietary for all manufacturers.

The only way to get official data on that is to dismantle an eyepiece and test using a microscope.

That is NEVER going to be done.

The best we're going to get will be interferograms of surfaces or wavefront measurements.

When we're lucky, we'll see the Lyot test results, the most illustrative test for surface polish.

I am actually surprised that nobody has dissected an eyepiece to examine it under a microscope, given the depth of analysis and declarations of supremacy that certain brands have attributed to them. 

[CrazyPanda]

I am actually surprised that nobody has dissected an eyepiece to examine it under a microscope, given the depth of analysis and declarations of supremacy that certain brands have attributed to them. 

There's a guy in my astronomy club that does material analysis with an electron microscope for a living. I asked him for his thoughts on using the microscope to analyze eyepiece optic surface roughness, and he said that because the chamber is so small, you would have to destroy an eyepiece get a lens fragment small enough to fit in the chamber.

 

I wonder if a conventional optical microscope would offer sufficient resolution.
 

Edited by CrazyPanda, 28 September 2023 - 04:50 PM.

[alnitak22]

There's a guy in my astronomy club that does material analysis with an electron microscope for a living. I asked him for his thoughts on using the microscope to analyze eyepiece optic surface roughness, and he said that because the chamber is so small, you would have to destroy an eyepiece get a lens fragment small enough to fit in the chamber.

 

I wonder if a conventional optical microscope would offer sufficient resolution.
 

Or you could just look through them in a scope and see if they satisfy you! I’ve done that for years with umpteen brands and know what fits my needs best.

Edited by alnitak22, 28 September 2023 - 05:08 PM.

[SandyHouTex]

Use Google Translate to read sections, then.

Note that the data is at f/3.5 and f/7.

Polish information is going to be proprietary for all manufacturers.

The only way to get official data on that is to dismantle an eyepiece and test using a microscope.

That is NEVER going to be done.

The best we're going to get will be interferograms of surfaces or wavefront measurements.

When we're lucky, we'll see the Lyot test results, the most illustrative test for surface polish.

I posted that I bought two microscopes with dark field lights that shine the light on the stage from the side.  It is specifically used to highlight things like scratches and digs.  I just need the motivation.

[SandyHouTex]

That makes sense- like McD’s “secret sauce” recipe, or CocaCola’s, or any of a thousand famous marketing details- kept under lock & key.

 

Now, I’m curious, if Orion or APM, etc. we’re to approach an “offshore” EP manuf., wanting 5,000 units of XYZ EP design made to their specs- do they simply click boxes on a pre-cooked drive-thru menu board? Would surface polish even be on such a menu? Who is it that makes such a choice?… and where in the pipeline is it made?

Actually the military does it all of the time.  In fact in many optics, especially laser optics, scratch/dig are part of the contract. 

 

Carl Zambuto guarantees his mirrors to have a laser polish of scratch/dig 10/5.  If he can do it and tell us, I don't see why eyepiece manufacturers can't.

[SandyHouTex]

The good news is that here in Texas fall will be here next week, and if congress lays me off, I'll have all kinds of time to do some more looking at Saturn and Jupiter with my TPLs.  I hope to compare them to the two ZAO Is I have and the Tak Orthos.  The Tak Orthos come in 12.5mm, 18mm, and 25mm so it should be easy to compare them.

[SteveC]

The good news is that here in Texas fall will be here next week, and if congress lays me off, I'll have all kinds of time to do some more looking at Saturn and Jupiter with my TPLs.  I hope to compare them to the two ZAO Is I have and the Tak Orthos.  The Tak Orthos come in 12.5mm, 18mm, and 25mm so it should be easy to compare them.

I just ordered  the 18mm. I'm heading south to Florida tomorrow and I'll compare it to my 16mm  ZAO II and 16mm Supermono. That's the best I can do for the sake of comparison. I have nothing else close to 18mm, so regardless of the results, it's a keeper. I almost considered buying the 25mm and comparing it to the 25mm ZAO, but that was idiocy. That was old SteveC of long ago buying duplicate eyepieces for comparison. 

[SandyHouTex]

I just ordered  the 18mm. I'm heading south to Florida tomorrow and I'll compare it to my 16mm  ZAO II and 16mm Supermono. That's the best I can do for the sake of comparison. I have nothing else close to 18mm, so regardless of the results, it's a keeper. I almost considered buying the 25mm and comparing it to the 25mm ZAO, but that was idiocy. That was old SteveC of long ago buying duplicate eyepieces for comparison. 

That will be a great comparison.

[PatientObserver]

Last night, I loaded the Pentax XW 20 into my Takahashi Turret and compared it with the TPL 25 and TPL 18. I had the turret install in the Mewlon 180C. The views were so similar that I could not notice any differences other than field of view. There may have been subtle differences, but since I needed to adjust focus for each eyepiece and my visual memory is not good enough to store a perfect image, I rate them both as excellent.

The TPL is perfect for the Takahashi Turret (and I imagine binoviewers). For use in my Tele Vue Everbrite diagonal, I prefer the Pentax.

[Mike B]

 

…. 

At any rate, seeing was so good it was stupid to waste it comparing these eyepieces. Switched to the 6 Ethos which is every bit as sharp and contrasty as any "planetary" eyepiece, and at 330x, the view was incredible.

Also decided to do some imaging to take advantage of the seeing.

Nice that NASA gave you time on the Hubble! Very generous- good of them  

[scoale]

I recently acquired the 12.5mm TPL and 4mm TOE.  I also own 11mm and 13mm Delites, which I compared to the 12.5mm TPL for several hours this morning while viewing Jupiter.thru my C11 and my Mewlon 210.

 

Observing conditions

Jupiter was well placed this morning between 55 and 65 degrees during my session.  Jupiter's size was a robust 47.  Astrospheric, Good to Stargaze, Cleardarksky, and Meteo Blue were forecasting 3/5 seeing at best but I estimate actual seeing at 4/5.  Even with the large aperture I was using I was seeing decent airy disk and ring detail at 350x.  Both scopes were decently thermally stable via a combination of several hours of passive cooling and some active cooling with Lymax cat coolers (the Mewlon did, however, exhibit a small degree of pluming during the session).  Ambient temp was 60 degrees at start of session, dropping about 1 degree/hour during session, and humidity was at 95%.

 

C11

I started the session with the C11 at 254x.  But the best combination of color, contrast, and resolution was achieved at the 215 to 224 range with the 12.5 TPL and 13mm Delite. The north polar region was well shaded and yellowish, with a thin brown north north temperate belt and a very faint north temperate belt. The NEB included several embedded ovals and there was a hint of festoon shading in the equitorial zone. The GRS was transiting and was richly colored and was surrounded by irregular white clouds.  The SEB also had an embedded cloud streak to the left of the GRS and embedded oval to the right.  The south tropical zone was apparent and there was myriad faint belt ripples and irregularities in the shaded southern region.  There was also a very faint oval in the southern region below the GRS.

 

Okay, with all of that build-up, the punch line is the best view was had with the last eyepiece I looked through.  There wasn't any detail visible in the TPL that I couldn't see in the Delite, and the color rendering and contrast seemed on par.  The Delite, of course, has the FOV and eye relief advantage.  The TPLs eye relief was not an issue for me.

 

Mewlon 210

Switching to the Mewlon, the image at 185x with the 13mm Delite is sharp; etched during moments of better seeing.  As Jupiter continues to rotate some very prominent ovals and more distinct festoon activity emerges.  The southern region belts also appear more distinct. While observing with the Mewlon I had two separate instances where following the 12.5mm TPL with the 13mm Delite seemed to result in improved resolution and contrast.  I also noted the FOV and eye relief advantages a bit more during the session with the Mewlon. I didn't see any detail in the Delite that I wasn't seeing in the TPL, and color and contrast were nearly indistinguishable - but I did have that immediate impression of an improved view when switching to the Delite two separate times (I probably switched between the two eyepieces 4 or 5 times overall.

 

Conclusion

 

So there you have it. I give the edge, on this night, to the Delite.  That said, I am glad I purchased the TPL and anticipate using it regularly.  It will get plenty of opportunity to change the ranking- but mostly I'm just going to enjoy it.

Edited by scoale, 30 September 2023 - 05:00 PM.

[CrazyPanda]

The funny part about all this testing between the 12.5mm TPL is and 13 DeLite is learning how absolutely superb the 13 DeLite is.

 

I know 25585 gives the nod to the 18.2 and 15 DeLites - which I agree are astonishingly good - and I would add the 13 DeLite to that mix as well. Unbelievably sharp, crisp, contrasty, and rich with snappy focus.

Edited by CrazyPanda, 02 October 2023 - 08:18 AM.