Couder mask

[JRM]

Hi All,

  I no longer have the computer my drawing program was on and I need to make a 7 zone mask for the 20" project I am currently working, does anyone

know of a program that is able to print a multi page drawing of 20" mask?.

 

Thanks

Rick M

 

[Dr_Ju_ju]

Hi Rick,

Up front, I've never made or printed a Couder mask, but....  There are some videos on youtube detailing the plans, and you could use an on-line service e.g. OnShape (https://www.onshape.com/) where you could design a mask. 

As for printing, as long as you have a reasonable quality printer, able to print large sheets (A3 European size), then even Window$ is able to split & scale appropriately...

[JRM]

Thanks for that Julian

Rick M

[Chriske]

Do not misunderstand me : Not that it is wrong using 7 zones to test a mirror at all. I think it's a waste of time.
All my life I always used a three zone mask, even for large mirrors. Making the curve smooth in the process there's no need to measure between these 3 zones. If there's a raised or a depressed zone between my 3 measuring-points I deal with it without measuring that raised/depressed zone.
What I do during every test session is making a focogram of the surface. That picture is always taken when the knife is exactly at the 70% zone.

Ask 10 mirror-makers how they grind and polish a telescope-mirror, you'll get 11 different answers... And most of the time, they all lead to a good mirror...

[JRM]

Thanks for that Chriske, no misunderstanding at all,sound like a good idea for me at the moment, I just need to get a mask made,

found a program, it will print a 20" mask with as many zones as you like without the center zone but it does not give the measurement,

so still looking.

Rick M