Good Cheap Mirror

[supernova1965 (Warren)]

I was wondering if the mirror in the scope part circled in this add from the current AS&T could be used as a replacement for a DOB mirror because it would be a cheap way to replace my damaged mirror.

It is a Meade LXD55 10" SNT Optical Tube - Broken corrector plate
Primary and secondary mirrors, cells and focuser OK

Thanks


Warren

[Satchmo]

The primary is no use without the corrector plate, unless it is refigured.

[supernova1965 (Warren)]

Originally Posted by Satchmo

The primary is no use without the corrector plate, unless it is refigured.

Thanks for the reply so no good for me I wondered if I could use the corrector plate from my scope sorry if this is a NOOB thought I still don't know all there is to know about scopes.

[bojan]

Those mirrors and corrector plates come as matched sets.. so this is not worth the trouble.

[JethroB76 (Jeff)]

Originally Posted by supernova1965

Thanks for the reply so no good for me I wondered if I could use the corrector plate from my scope sorry if this is a NOOB thought I still don't know all there is to know about scopes.

As above, but what scope do have that has a corrector plate? you only have a dob dont you?

[supernova1965 (Warren)]

Originally Posted by JethroB76

As above, but what scope do have that has a corrector plate? you only have a dob dont you?

this shows how much I don't know I am not really sure what a Corrector Plate is

[erick (Eric)]

Wikipedia is your friend here.

Perhaps some reading on:-

http://en.wikipedia.org/wiki/Schmidt-Newton_telescope

and on "Newtonian reflector"

http://en.wikipedia.org/wiki/Newtonian_telescope

[supernova1965 (Warren)]

Originally Posted by erick

Wikipedia is your friend here.

Perhaps some reading on:-

http://en.wikipedia.org/wiki/Schmidt-Newton_telescope

and on "Newtonian reflector"

http://en.wikipedia.org/wiki/Newtonian_telescope

Thanks Erick just what I love Home work

[mic_m (Michael)]

The corrector plate (commonly a Schmidt corrector plate)is a piece of glass at the front of catadioptric telescopes (i.e. Schmidt–Cassegrain and Schmidt–Newton telescopes) primary optical lens. This piece of glass is an aspheric lens which is designed to correct the spherical aberration present in the spherical mirrors used in these scopes. Here is a diagram to show the relationship of these components.

[ausastronomer (John Bambury)]

I will take the homework out of it for you.

The Meade 10" Schmidt Newtonian uses a 10"/F4 spherical primary mirror. Your 10" Meade Starfinder has a 10"/F4.5 parabolic primary mirror. The two mirrors have an entirely different shape and focal length and are not interchangeable as Satchmo said, without complete refiguring.

Keep your eyes open on Astromart for a 2nd hand mirror, or a damaged Meade Starfinder. A new or refigured 10"/F4.5 mirror would cost more than the scope is worth, considering you can buy a complete new 10"/F5 GSO dob for about $700 to $800.

Cheers,
John B

[supernova1965 (Warren)]

Originally Posted by ausastronomer

I will take the homework out of it for you.

The Meade 10" Schmidt Newtonian uses a 10"/F4 spherical primary mirror. Your 10" Meade Starfinder has a 10"/F4.5 parabolic primary mirror. The two mirrors have an entirely different shape and focal length and are not interchangeable as Satchmo said, without complete refiguring.

Keep your eyes open on Astromart for a 2nd hand mirror, or a damaged Meade Starfinder. A new or refigured 10"/F4.5 mirror would cost more than the scope is worth, considering you can buy a complete new 10"/F5 GSO dob for about $700 to $800.

Cheers,
John B

Thanks John I at present intend to get the Mirror recoated probably next wet season when I can't use it. I did do the homework but to be honest I couldn't understand much of what I read but after your explanation it all became clear. Even with the coating loss on my mirror I can still get some great views even of nebula and galaxies.