I am confused about the Coronado SolarMax II 60mm Ha Etalons which are being sold with the description that they are for Double Stacking. I have read a caution by Meade/Coronado that the separately purchased Double Stack (DS) etalon is not to be used as a "standalone filter."
Does that mean that a DS etalon is manufactured to different specifications than a Primary etalon, or are they both built the same?
I am wondering if the DS etalon is lacking safe filtering which a Primary etalon would have, in order to minimize the loss of Ha light to the Primary etalon? -- OR is the stated caution simply indicating that a DS etalon cannot be used without the appropriate blocking / ITF filter (BF10, BF15, etc.) as would always be required usage with a regular Primary etalon?
I have not been able to get any answers by Googling this, and Meade's telephone customer service cannot be reached by phone due to COVID. And for that matter, I have seen a comment that Meade CS is not very familiar with the Solar product line, so would an answer from them even be correct?
I am hoping one or more of the experienced and knowledgeable Solar experts here can enlighten me.