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Leica ASPH Zoom Paracorr setting

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#1 johnnyha

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Posted 31 January 2013 - 03:34 AM

Any idea what the best Paracorr 1 setting is for the Leica ASPH Zoom with 2" adapter? My preliminary tests show it appears to need to be set with the tunable top all the way down (setting 5). Even this is not enough "in", but at this setting I'm happy to report I do get a sharp image across 100% of the FOV in my f4.65 dob. :cool: How 'bout y'all?

#2 Doug Culbertson

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Posted 31 January 2013 - 06:30 AM

That's the setting that I use as well.

#3 Víctor Martínez

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Posted 31 January 2013 - 06:48 AM

Johnny, you say:
"I'm happy to report I do get a sharp image across 100% of the FOV in my f4.65 dob".
This is only with the eyepiece and Paracorr, or adding a Barlow lens also to the optical train

#4 btom

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Posted 31 January 2013 - 07:45 AM

Ditto that question?

#5 Doug Culbertson

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Posted 31 January 2013 - 08:59 AM

In my case, I get sharp stars almost all the way across the fov at all magnifications with the Leica ASPH. I can't say for sure that it's 100%, but it's at least as good as my 31mm Nagler at the same setting. Not perfect, as it could stand a bit more inward travel, but close enough for rock and roll. FWIW, that's in my 14.5" f/4.3 Starmaster.

#6 johnnyha

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Posted 31 January 2013 - 07:00 PM

Johnny, you say:
"I'm happy to report I do get a sharp image across 100% of the FOV in my f4.65 dob".
This is only with the eyepiece and Paracorr, or adding a Barlow lens also to the optical train


This is with only the Leica ASPH zoom and a Paracorr 1, no barlow. Sharp to the edge! I was testing on the Moon so there was no ambiguity, 100% of the FOV was clean and sharp. :)

With a barlowed Leica ASPH zoom I find the Paracorr is not needed, I get a sharp image across the FOV.

With an unbarlowed, unParacorred Leica ASPH zoom I get a soft image starting 2/3 of the way to the edge.

#7 Víctor Martínez

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Posted 01 February 2013 - 05:18 AM

Can you tell me anything about focus travel of this eyepiece + Barlow Antares 1.6X compared to an eyepiece Ethos. In my focuser, a JMI Ev-1n, I have focus with all my eyepieces, from ES 30 mm until 10 mm Ethos, all barlowed also with Antares 1,6X included.

#8 Víctor Martínez

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Posted 02 February 2013 - 04:10 PM

Nobody can answer this question?. Anyone could know what is the value of the field stop of this eyepiece?.

#9 johnnyha

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Posted 02 February 2013 - 07:59 PM

I actually went out specifically to check last night Victor but it had clouded up, and looks like rain tonight.

#10 andydj5xp

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Posted 03 February 2013 - 03:13 AM

Anyone could know what is the value of the field stop of this eyepiece?.


Victor,

the field stop diameters for the various ASPH settings can be seen here

Info about the infocus requirements as compared to some other eyepieces is given here

I don't remember the infocus requirement for the Antares 1.6x Barlow, but normally the focus travel with and without Barlow is very similar if not the same. Therefore, if the Leica ASPH can be fosused stand alone it will also achieve focus with the Antares Barlow.

Andreas

#11 Víctor Martínez

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Posted 03 February 2013 - 05:08 AM

Johnny, thanks for the inconvenience you are taking to check it, I really appreciate.
Andreas thank you.
Well, based on the Tammy says in his post, the distance of the field stop of Leica zoom with the Starlight adapter, in respect of the focal plane, would be of -16'9 mm (-0'66"), always taking values of Televue site of approximately location of field stop.

#12 johnnyha

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Posted 03 February 2013 - 08:57 PM

Victor - the Leica ASPH zoom/1.6X Antares barlow requires 1/4" more infocus than the zoom alone. The zoom alone is parfocal with the 31T5 Nagler.

The 13 Ethos requires 3/4" more outfocus than the 1.6X barlowed Leica ASPH zoom.

#13 Víctor Martínez

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Posted 04 February 2013 - 03:34 AM

The 31T5 Nagler is, in theory, parfocal with 21mm Ethos. Consequently, the Leica ASPH zoom/1.6X Antares barlow requires 1/4" (6'35mm) more infocus that 21mm Ethos. According to the TeleVue Ethos eyepieces and in theory, the 13mm Ethos requires 0'9" (22'86mm) more outfocus than the 1.6X barlowed Leica ASPH zoom. With this I can get an idea that the travel focus I need.
Thank you very much Johnny.






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