Fluorite EP's?

[LewisM]

Did/does any manufacturer make fluorite EP's? I know Baader makes SOME fluorite accessories, but any EP's at all?

And who is making FPL53 EP's? I guess a second best option

[AG Hybrid (Adrian)]

Your obsessed with this fluorite stuff aren't you? You just can't get enough of it, can you? I bet you know which brand of tooth paste and which flavor variants have the highest content of fluorite in parts per million off by heart.

Traditionally, eyepiece manufacturers are "hush-hush" about what the content and makeup of the glass they use in their eyepieces. We know Pentax and Vixen market Lanthanum as a major component of their eyepieces. But, manufacturers like Televue as far as I know have never published that information.

I'm surprised you don't know the answer to your own question. If I was going to ask this question you would have been the first person I would have asked.

[Larryp (Laurie)]

Originally Posted by AG Hybrid

Your obsessed with this fluorite stuff aren't you? You just can't get enough of it, can you? I bet you know which brand of tooth paste and which flavor variants have the highest content of fluorite in parts per million off by heart.

Traditionally, eyepiece manufacturers are "hush-hush" about what the content and makeup of the glass they use in their eyepieces. We know Pentax and Vixen market Lanthanum as a major component of their eyepieces. But, manufacturers like Televue as far as I know have never published that information.

I'm surprised you don't know the answer to your own question. If I was going to ask this question you would have been the first person I would have asked.

No fluorite in toothpaste, I'm afraid! Either sodium or stannous fluoride
Fluorite is calcium fluoride.

[AG Hybrid (Adrian)]

Originally Posted by Larryp

No fluorite in toothpaste, I'm afraid! Either sodium or stannous fluoride
Fluorite is calcium fluoride.

We'll. I assume he knew that was the case too.

[Hans Tucker (Hans)]

The only eyepiece manufacturer I have ever come across that gave a name to the glass they used in their eyepieces was Vixen with their LV series which uses Lanthanum glass which itself is a low-dispersion. But being a Vixen fan Lewis you would have already known this bit.

Takahashi uses ED Extra-low-dispersion glass in their LE & UW series which is also used in the TMB, Televue and Saxon brands. Now FLP-53 is considered an Extra-low-dispersion glass so by association FLP-53 could be used to manufacture one or more elements in these multi element designed eyepieces. Cheaper eyepieces just use flint and crown glass.

I have not come across any manufacturer that manufactures fluorite eyepieces possible due to cost and difficulty working with the material particularly since is is a fragile material.

I do have a Baader Flat Field Converter (FFC) that has elements manufactured from fluorite and that was a very expensive item to buy.

[alocky (Andrew lockwood)]

Originally Posted by Larryp

No fluorite in toothpaste, I'm afraid! Either sodium or stannous fluoride
Fluorite is calcium fluoride.

You could always brush with dioxygen diflouride for that extra clean feeling...

[Allan]

TeleVue use Lanthanum, they even publish it on their website somewhere. Fluorite would be a problematic material to construct eyepieces from. Just stick to the drug in your objectives.

[Regulus (Trevor)]

I hesitate to suggest Lewis this given the things I have read when his name is mentioned, but Cris (Astro_Melb) seems to have a deep knowledge of manufactures and decades of experience in trading in quality optics.
Perhaps a message to him might help.
Just a thought.

Trev

[Profiler (Profiler)]

Originally Posted by Allan

TeleVue use Lanthanum, they even publish it on their website somewhere. Fluorite would be a problematic material to construct eyepieces from. Just stick to the drug in your objectives.

I would love to know where this appears in print

[RB (Andrew)]

Careful you don't get Fluorite in your eye from the eyepiece, it'll make you stupid just like town water does.

[Hans Tucker (Hans)]

Originally Posted by Profiler

I would love to know where this appears in print

I had to go looking and found a suggestion of Televues uses of Lanthanum here:
http://www.televue.com/engine/TV3b_p...d=78#.VJqRRA8Y

And I found other websites that state that Lanthanum was used in the Panoptics and Radian eyepieces.

[ariefm71 (Arief)]

The link also mentioned TV uses "fluorite type" glasses.

[AG Hybrid (Adrian)]

Originally Posted by Hans Tucker

I had to go looking and found a suggestion of Televues uses of Lanthanum here:
http://www.televue.com/engine/TV3b_p...d=78#.VJqRRA8Y

And I found other websites that state that Lanthanum was used in the Panoptics and Radian eyepieces.

Well how 'bout that? "The finest performance requires the finest materials such as high index lanthanum and fluorite type glasses, in some cases costing up to 15x more than ordinary glass types."
I suppose FPL designated glass would be considered Fluorite type glass.

[Hans Tucker (Hans)]

Originally Posted by AG Hybrid

Well how 'bout that? "The finest performance requires the finest materials such as high index lanthanum and fluorite type glasses, in some cases costing up to 15x more than ordinary glass types."
I suppose FPL designated glass would be considered Fluorite type glass.

Not quite all FPL, only FPL-53 (artifical fluorite) has been regarded as being close to calcium fluorite type glass because its abbe value (94.93) is close to that of genuine fluorite (94.99). FPL-51 has an abbe number of 81.54 and FPL-52 has an abbe number of 90.29.

Apparently FPL stands for:

F - Fluorite
P - Lead
L - Low refractive index
51, 52 or 53 - The 51st, 52nd or 53rd glass in its family

[Allan]

Originally Posted by Profiler

I would love to know where this appears in print

There you have it

[AG Hybrid (Adrian)]

Originally Posted by Hans Tucker

Not quite all FPL, only FPL-53 (artifical fluorite) has been regarded as being close to calcium fluorite type glass because its abbe value (94.93) is close to that of genuine fluorite (94.99). FPL-51 has an abbe number of 81.54 and FPL-52 has an abbe number of 90.29.

Apparently FPL stands for:

F - Fluorite
P - Lead
L - Low refractive index
51, 52 or 53 - The 51st, 52nd or 53rd glass in its family

Those numbers would suggest a major difference between the common glasses used in telescopes, FPL-51 and FPL-53. But, how does that translate at the eyepiece or at the CCD chip? IS the color correction 15-20% better or does it scale differently?

[Hans Tucker (Hans)]

Originally Posted by AG Hybrid

Those numbers would suggest a major difference between the common glasses used in telescopes, FPL-51 and FPL-53. But, how does that translate at the eyepiece or at the CCD chip? IS the color correction 15-20% better or does it scale differently?

I would think the use of abbe numbers would apply to any lens elements used in optical design be it telescope, camera lens or an eyepiece. It is all about matching lens elements to achieve the focus of the incoming light to a single point. With eyepieces you want to achieve magnification whilst maintaining control over contrast, sharpness and color definition.

When designing eyepieces you still have issues like chromatic aberration and spherical aberration to correct for hence the need to match as close as possible the lens elements whilst trying to get and maintain the maximum light transmission.

[LewisM]

Thanks for the serious and sarcastic answers - all much appreciated.

Yes, fluorite is the wonderful elixir of life. ED is just a cheap(er) substitute

[Camelopardalis (Dunk)]

Originally Posted by AG Hybrid

Those numbers would suggest a major difference between the common glasses used in telescopes, FPL-51 and FPL-53. But, how does that translate at the eyepiece or at the CCD chip? IS the color correction 15-20% better or does it scale differently?

I'm seeing a difference in the cheaper glass with my new camera I tried out last weekend, the blue halos are more prevalent than with my other cam, although it's probably mostly because my little scope is only a doublet

[brian nordstrom (As avatar)]

Great discussion going on here , thanks Lewis .

Hans , a few years ago I had a full set of the beautiful Vixwn LV's , beautiful eyepieces in every way , but I grabbed an 18mm Radian from the classifieds here and now have a full set of the TV's , they are a better eyepiece IMOO , so sold the LVs to a lucky IIS'r .

The Radians do impart a more natural tinge to the Moon and Planets in my eyes and these are my favourite night sky objects , in my refractors more natural hues , but especially in my 9 1/4 inch Cat the Radians really shine in this scope .
They are , the ( LV's) and Radians special eyepieces for luna/planetary viewing but I do find my Panoptic's better for deep sky, cleaner ? perhaps , very subjective subject .

Great discussion this one and a merry Christmas all .

Brian.

Originally Posted by Hans Tucker

I had to go looking and found a suggestion of Televues uses of Lanthanum here:
http://www.televue.com/engine/TV3b_p...d=78#.VJqRRA8Y

And I found other websites that state that Lanthanum was used in the Panoptics and Radian eyepieces.