RASC Hamilton [ Special Announcement] Transit of Venus - June 5

[Ron Shields]

Dear Mark,

Thanks for the advice. My apologies but the lens is only 60 mm, not 90 mm as mentioned before. When I use it for solar observation, I use the small solar opening of 38 mm (11/2”) in the large lens cap along with the solar filter. It was used to observe the entire annular eclipse that passed through the area on May 10, 1994 without incident as well as for general solar observation through the years. I have never had any heat issues at all generated on the eyepiece even when the image is rear projected through an eyepiece without the solar filter. Although the filter is good, rear projection of the sun through the telescope is the best and safest route for solar observations, especially for large groups. I have not blinded anyone yet in the 40 years of using it in this regard. Your concerns are noted and will be taken under advisement for the transit.

Regards,
Ron Shields

From: Mark Kaye 
Sent: Saturday, May 12, 2012 7:01 AM
To: astronomers at hamiltonrasc.ca 
Subject: Re: RASC Hamilton [ Special Announcement] Transit of Venus - June 5

On 12-5-12 3:26, rjshields at sympatico.ca wrote: 
  I have a 90mm refractor with a solar filter that threads into the eyepiece. I can bring it to the gathering. Have used it over the years for solar observations and eclipses. It is what got me interested in the stars in the first place. Hate parting with an old friend.


   This type of solar filter is dangerous and should not be used.  The only method of solar viewing that is safe has the filter in front of the telescope.  The heat generated by the Sun hitting that filter will cause it to break and allow the Sun through.  Please do not use this eyepiece filter.

-- 
   Clear Skies!
               MK

http://www3.sympatico.ca/mark.kaye/index.htm

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