Darken Back and Edge of Secondary Mirror??

Post by **weixing** » Tue Feb 13, 2007 6:13 pm

Hi,
I just replace my secondary mirror to slightly larger secondary mirror. Unlike the old secondary mirror, this new secondary got a transparent back, so that you can actually see the aluminum coating from the back too... like a normal mirror. The old secondary got a translucent back.

While waiting for the silicone adhesive to fully cured, I was wondering do I need to darken the back and the edge and what is the best way to do it??

Have a nice day.

kayheem · Post by **kayheem** » Tue Feb 13, 2007 9:08 pm

For my ex-10 incher, I used a black felt marker. While it was not matt black, it was certainly a big improvement from what I can see thru the focuser.

Post by **weixing** » Fri Feb 16, 2007 8:54 pm

Hi,
Complete the "darkening" of my new secondary mirror edge and back.

Hope tomorrow night weather is clear for me to test my "reborn" C8N.

Have a nice day.

elton · Post by **elton** » Sat Feb 17, 2007 10:19 am

Wow, you really went all out to blacken it. The paint used seems to be quite reflective though.

kayheem · Post by **kayheem** » Sat Feb 17, 2007 10:34 am

How did u do it, Weixing? Care to share?

Post by **weixing** » Sat Feb 17, 2007 1:57 pm

Hi,
I initially plan only to darken it using a black paint marker, but the black paint marker is very reflective and the paint won't "stick" easily on the smooth glass surface. So in the end, I spray a layer of the Nippon flat black paint over it. Although it still a bit of reflective at certain angle, it better than the black paint marker and since it at the back of the mirror, I think it won't affect that much.

Anyway, I haven't blacken the front edge, as spray the flat black paint is difficult and black paint marker is too reflective... still looking for a solution for that.

Have a nice day.