Do you know the Lunt 160mm etalon filter?

[mami813]

Hello everyone.
Do you know the Lunt 160mm etalon filter?
There is a 160mm filter made to order in Korea.
I made an observation today. It was the best..
Do you know the history of this filter?
Unfortunately, a 160mm filter was used in the 150mm telescope. It's unfortunate.
Please understand that my English is not fluent.
thank you.

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[Bob Yoesle]

This filter is mentioned here, and I was told only a few were made. I believe they sold for around $14,000 - $16,000, and thus probably were not commercially viable - therefore the same fate as the Coronado SM140. The one shown indicates it was the fourth one made in the year 2010.

[Dennis]

must be amazing for visual observation.. but only if you have often good seeing.
for imaging on the other hand i dont see much advantage over the cheap solutions with rear mounted etalons.

[torsinadoc]

This filter is mentioned here, and I was told only a few were made. I believe they sold for around $14,000 - $16,000, and thus probably were not commercially viable - therefore the same fate as the Coronado SM140. The one shown indicates it was the fourth one made in the year 2010.

Any thoughts on why they didn’t continue development of the pressure tuned front etalon (mentioned in the link)

[mami813]

must be amazing for visual observation.. but only if you have often good seeing.
for imaging on the other hand i dont see much advantage over the cheap solutions with rear mounted etalons.

hello dennis
Thank you for answer.
I hope the transaction with you goes well.
Jongho

[mami813]

This filter is mentioned here, and I was told only a few were made. I believe they sold for around $14,000 - $16,000, and thus probably were not commercially viable - therefore the same fate as the Coronado SM140. The one shown indicates it was the fourth one made in the year 2010.

hi Bob
Thanks for sharing some of the information you know.

[christian viladrich]

Waow, this is a big one ! Thanks for the photo.
If was wondering what is the size of the main telescope on which the TOA 150 is attached to ?

Bob, what about going triple-stack with this 160 mm etalon ;-)

[marktownley]

Nice! Interesting to know and thanks for sharing!

[Bob Yoesle]

Any thoughts on why they didn’t continue development of the pressure tuned front etalon (mentioned in the link)

No definite ideas - although it would take a clear window and the ERF for sealing the etalon - which would add weight to an already heavy etalon/ERF. Then it would need to be vacuum-tuned with a precision pump. For the 160, the usual piston might not have enough volume for the job.

Bob, what about going triple-stack with this 160 mm etalon ;-)

Wowzer!!! - if I found one I might consider it !-0

[mami813]

Any thoughts on why they didn’t continue development of the pressure tuned front etalon (mentioned in the link)

No definite ideas - although it would take a clear window and the ERF for sealing the etalon - which would add weight to an already heavy etalon/ERF. Then it would need to be vacuum-tuned with a precision pump. For the 160, the usual piston might not have enough volume for the job.

Bob, what about going triple-stack with this 160 mm etalon ;-)

Wowzer!!! - if I found one I might consider it !-0

triple stack? Just thinking about it makes me excited!!
But there was no erf in front of 160mm.
There was a small erf filter on the back blocking filter.

[DeepSolar64]

WoW, what an etalon!! Though a bit smaller than the etalon the TOA150 is a top notch scope and should perform excellently with it. That's a big scope the TOA150 is mounted on!!

James

[christian viladrich]

Hello Mami,
Could you have a picture taken from the front of the etalon to see whether there is any central spacer ?
Any image of the blocking filter ? Is is a "classic" one ?

[Bob Yoesle]

I personally would NEVER mount an etalon - let alone the monster ones - on the dew shield of any telescope. You want to mount it directly to the objective lens cell proper if at all possible.

I would think the LS160 etalon would be best served by the "root 3" spacer system - and a single central spacer would have violated the Coronado Patent that Meade inherited from David and Andy Lunt et.al.

[rsfoto]

I personally would NEVER mount an etalon - let alone the monster ones - on the dew shield of any telescope

Hi Bob,

You are correct. I have a TOA 130 and I have to say the play of this dew shield in the lowest position is quite play free and it looks as they have the dew shield in its shortest position. Just tested it on my TOA 130.

[mami813]

I personally would NEVER mount an etalon - let alone the monster ones - on the dew shield of any telescope. You want to mount it directly to the objective lens cell proper if at all possible.

I would think the LS160 etalon would be best served by the "root 3" spacer system - and a single central spacer would have violated the Coronado Patent that Meade inherited from David and Andy Lunt et.al.

hi Bob
you're right.
The etalon is made of three central spacers.
I also told the owner that it is best to mount it on the lens cell if possible.
Why should it be mounted on a lens cell?
thank you.

[MapleRidge]

Mami...

The dew shield is too flexible to support an etalon like this without sagging and ruining the ability to keep the etalon optics aligned properly.

I have the Lunt 75mm etalon, and it is too heavy to mount on the on the dew shield of my 80mm pressure tuned.

Still, it is an impressive sight!

Brian

[mami813]

Hello Mami,
Could you have a picture taken from the front of the etalon to see whether there is any central spacer ?
Any image of the blocking filter ? Is is a "classic" one ?

hi christian viladrich
Sooner or later, it will be shipped to me to manufacture the objective lens cell adapter.
Then I'll upload detailed equipment pictures again.
Jongho

[marktownley]

Thanks Jongho, keep us updated with plenty of pictures.