Where can you find the plans to make a focus reducer?

Question

I have a mead 70az-tr when I try and do some astrophotography I can not get it to focus the problem is I can not get the camera in close enough I know I need a focu reducer but my question is how do you make a focus reducer and what do I need ?

Answer 1

You don't want to make your own focal reducer (not focus reducer) as that will be beyond you, unless you are an expert at optical configuration and reducing lenses. You won't find any plans to assist you as optical companies protect their designs fiercely and keep them a "secret".

That telescope is not suitable for astrophotos as it is a cheapo achromatic which will be full of false colour and optical shortcomings, remember astrophotography magnifies any defects in the OTA, Mount and Camera cumulatively so a 70mm f5 is meaningless without considering the quality of all 3 items.

Anyway, you are obviously going to have a go at it, but at 70mm and f5 you do not need a focal reducer to get your camera to focus. Your problem is that you do not have enough back-focus so you will need to extend the focusing tube by at least 100mm to come to focus. That is simple you just buy a cheap extension tube that takes a 1.25inch accessories and extend the focus tube by 100mm, or try the diagonal which should be a similar length. Or you can buy a Meade camera adapter if there is one that fits your camera, but the average consumer digital camera is not very good at astrophotography.

Don't expect too much though. Good luck, you will need more than that, a miracle perhaps to get that mount, scope and camera to perform any tricks.

Answer 2

you don't make it. you buy it.

how are you coupling the camera to the telesscope?

how were you planning to do astrophotography without an equatorial mount?