Lunt CaK module with oil spaced objectives

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
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urassner
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Lunt CaK module with oil spaced objectives

Post by urassner » Sat Aug 20, 2016 12:00 am

I am new to this forum, but have been dabbling in some solar observing and imaging for a couple years. I have a Quark Chromosphere that I am happy with. Daystar advices to use a UV/IR cut filter with scopes larger than 80 mm in aperture and also state that the UV/IR cut filter should not be used with oil spaced objectives.
The Lunt CaK module has a shiny filter/glass at the telescope side, but I have not been able to find out if that functions like a dichroic UV/IR cut filter and would make the module not suitable for oiled objectives. I could not find helpful information on the Lunt website and have called Lunt a few times without receiving a helpful answer.
While I have a air spaced telescope, my travel telescope has an oil-spaced triplet and I would love to be able to do some CaK viewing when traveling.

Thanks.

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Montana
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Re: Lunt CaK module with oil spaced objectives

Post by Montana » Mon Aug 22, 2016 7:05 am

I have a TEC140 and have been using the Lunt CaK module with it with no problem. I must admit, I stop it down to 100mm when using it and I only use it for around a hour, I never leave it tracking on the Sun all day. But I guess you use it at your own risk (don't blame me). To be honest I think if I had a full front ERF on the front for the Lunt I might get better images (less heating inside) but I don't know of an ERF for CaK other than the Beloptik tri filter and you can't get hold of those.
With the Quark I have a full front Baader D-ERF to protect the objective.
Alexandra

urassner
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Re: Lunt CaK module with oil spaced objectives

Post by urassner » Mon Aug 22, 2016 5:43 pm

Thank you for sharing your experience. This makes me feel better. I am not sure that there is a ERF that lets CaK through. I have not been bale to find transmission data for the Lunt or Daystar ERF.
Ulrich

piekielrl
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Re: Lunt CaK module with oil spaced objectives

Post by piekielrl » Fri Sep 02, 2016 3:07 am

I'm jumping in here late, but I had Omega Bob make me a full-aperture (95mm) CaK filter to rebuild my Coronado CaK 90 with. He can make thes in any size, and as wide or as narrow as you wish.
Attachments
Omega full aperture CaK filter on Coronado 90 1 of 2.JPG
Omega full aperture CaK filter on Coronado 90 1 of 2.JPG (237.3 KiB) Viewed 986 times

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