Re: [ATM] LWT setup questions

["john sherman" <atm@mail.johnspics.com>]

Hi again,

>Bit tough on the Couder mask that... 

More like tough on myself, for not being able to do what many others have. Couder's mask was a great improvement on the current knowledge, that's why it still has such great popularity. Instead of judging where the shadows are with a pinstick (e.g.), the mask hides all the distractions and shows you only what you need to see. 

I know the Couder test works very well, for those with the wherewithall to use it. Indeed, my superb new 22" mirror was figured primarily with the Couder test (not by me!). And it destroys the 22" mirrors I had previously that were made by a pro with an interferometer. 

I'm sorry, I did not mean to give the impression that there is anything "wrong" with Couder, just that it was too difficult for me, personally, to use. Now we have the LWT, which is SO much better (for me, anyway). 

>The pinhole!

Did you try the method where you stack many layers of foil, and shove a well-sharpened needle partway into it? You must sharpen your needle yourself. When I look at a standard sewing needle with a 25mm eyepiece, it appears far from sharp. Until I discovered that, my pinholes were quite poor. 

Take care,

John









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