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Off axis WL Filter Question

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6 replies to this topic

#1 Special Ed

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Posted 11 January 2017 - 11:34 AM

Hello,

 

I tried asking this question in the Cat forum but didn't get a response.  Does anyone here know?

 

Thanks in advance.



#2 George Bailey

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Posted 11 January 2017 - 01:09 PM

I don't think it would make a difference

(I never noticed a difference with my C8),

but it would be simple enough to test it out at different positions and see if you get a better view

at one of them with your scope.



#3 Special Ed

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Posted 11 January 2017 - 02:37 PM

Thanks for the response, George.  I'd like to experiment with it but the Sun won't cooperate by producing an AR.  Wouldn't matter anyway--cloudy forecast here through next Tuesday...



#4 David Gray

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Posted 12 January 2017 - 06:13 AM

Hi Michael….

 

I’m not really a solar observer but I use a 6” off-axis (clear) mask/diaphragm with my 16.3” scope on occasion for other objects and not found an optical issue.

 

However for your solar-mask pursuits I wonder about how much (if) the sun would heat the opaque area of the device – thus possibly rising thermals across the filter in some instances....(the 9 to 3-o-clock positions ???) – so perhaps a 6-o-clock position might be in order.  

 

Or wind-directed thermals might be the factor to consider/address….?

 

Just my speculations on the matter…….

 

Dave.



#5 Special Ed

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Posted 12 January 2017 - 08:54 AM

Hi Dave,

 

Thanks for the thoughts.  The opaque part of the filter is white so it should reflect away a lot of the Daystar's heat but probably not all.  It makes sense to keep the filtered opening at the bottom (6 o'clock) of the objective.  Good to hear from you.



#6 marktownley

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Posted 12 January 2017 - 02:40 PM

I don't think you will see any difference.  With a blank sun you will get an easier full disk with your 50mm scope.



#7 Special Ed

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Posted 13 January 2017 - 06:53 PM

Thanks, Mark.  You're probably correct.  As far as seeing the full disk, I have other telescopes (and my 15x70's) for that).  My 2" ep's give me very close to a full disk, but I am more interested in a high power view with the C14.

 

As luck would have it, a (sort of) break in the clouds this afternoon coincided with the emergence of AR2625 so I was able to try out my new off-axis filter.  It worked great.  Sketch can be seen here.

 

[Edit: AR2625 is now followed by newly designated AR2626 ]


Edited by Special Ed, 14 January 2017 - 10:35 AM.



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