troypiggo
30-03-2010, 06:27 AM
I have a SkyWatcher Black Diamond 10" Newtonian. The secondary mirror on it is only 50mm diameter on the narrowest side. It appears to be connected to the "stalk" with double-sided tape, and the stalk is narrower than the mirror, so I can see the back of the mirror when I look through the end of the scope.
I was thinking that something like the Kendrick split dew heater would be perfect, but it appears too big - for 75mm secondaries? It has been suggested that I could do a bit of a DIY resistor solution on the back of the mirror part exposed, but just exploring all options.
I read here from their website (http://www.kendrickastro.com/astro/newtonian.html) that they don't recommend the wrap-around heater because the double-sided tape just acts as an insulator, but when I emailed them directly and asked, that was the system they recommended provided I put something around the heater to insulate it.
I'm a little concerned about heating the stalk and the glue on the double-sided tape letting go.
Would there be a better way for me to fix the secondary to the stalk to alleviate this problem? Will it even be a problem? What glues have you used that handle heat ok?
I know we're only talking about tiny amounts of heat, only a couple of degrees above ambient typically. Just thinking of some accidental scenario where the dew controller settings get bumped or something silly happens and a little more heat gets produced. Don't want the secondary falling off and onto the primary.
I was thinking that something like the Kendrick split dew heater would be perfect, but it appears too big - for 75mm secondaries? It has been suggested that I could do a bit of a DIY resistor solution on the back of the mirror part exposed, but just exploring all options.
I read here from their website (http://www.kendrickastro.com/astro/newtonian.html) that they don't recommend the wrap-around heater because the double-sided tape just acts as an insulator, but when I emailed them directly and asked, that was the system they recommended provided I put something around the heater to insulate it.
I'm a little concerned about heating the stalk and the glue on the double-sided tape letting go.
Would there be a better way for me to fix the secondary to the stalk to alleviate this problem? Will it even be a problem? What glues have you used that handle heat ok?
I know we're only talking about tiny amounts of heat, only a couple of degrees above ambient typically. Just thinking of some accidental scenario where the dew controller settings get bumped or something silly happens and a little more heat gets produced. Don't want the secondary falling off and onto the primary.