Ebay Omega

[Wah]

Ebay Omega <0.1nm Halpha filter on sale!

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 1249wt_898


I wonder if the thicker one can be used as a large blocking filter for other solar telescopes :woohoo: :woohoo: :woohoo:

[solarchat]

ebay ads are directly embeddable in posts on solar chat for future reference. Check the toolbar above the message posting area.

[swisswalter]

Hi Wah

I had them here. I do not remember that on of the pair was thicker then the other. Where have you your information from ?

[Wah]

http://solarchat.natca.net/index.php/en ... al-filters

[swisswalter]

Hi Wah

thank you very much for the thread reference. So there are two different types on the market. Now I don't wonder any more, why we get different results from the Omega Halpha filters

[Wah]

It seems nobody can tell if the thicker one can be used as a cheap blocking filter.

[marktownley]

It seems nobody can tell if the thicker one can be used as a cheap blocking filter.

Missed this post, sorry Wah! I have bought 2 different sets of these off ebay and can confirm that certainly the ones I have cannot be used as blocking filters.

[Wah]

Do you have idea why? Is that safety issue or bandwidth issue? :huh:

[sullij1]

Hi Wah,

I own alll of the Omega Ha offerings, As I understand it, the thicker one is actually Omegas attempt at an etalon.. So the thick one "is" the etalon in the Omega system.

"The thin one is the blocking filter for the Omega etalon". As I understand it, blocking filters are manufactured for FSR of the etalon, each manufactuer FSR may be slightly different(dependent on etalon spacing). For example, Omega blocker may not work on a Coronado etalon because of FSR. So "bandwidth" may be an issue."

Link to Colin's paper:

http://www.designerinlight.com/solar/Et ... clePt1.pdf

See title THEORY and fig 4,5,and 6.