What should I look for in a refractor Diagonal?

Hi,

I recently purchased an Orion 80 ED APO which is currently in the mail on its way here. It does not have a diagonal which means I should start looking for one. However, I have very little experience with such things and have no idea what features to look for. I plan to be doing some photography and some visual observing through the scope.

Can anyone describe the basic principles of diagonals and/or point me towards some type of consumer research article regarding shopping for them?

I suggest that you consider a quality 2-inch dielectric diagonal, if it will fit in your scope's focuser. Several makes are available (Astro-Physics, Tele Vue and others), and the dielectric coatings are quite durable--especially when it comes to the occasional need for cleaning.

Ron
Equipment Forum co-moderator

PM sent.
Cheers, Paul

Having recently been on a diagonal quest myself you can read the results in Message #521269 in this forum.
One thing I found that most manufacturers don't tell you is how much space there is to seat your eyepiece without coming in contact with the diagonal mirror.
I never ran into this problem until I bought a hybrid 2/1.25" eyepiece. It bottomed out ON the mirror. Fortunately It was light out and I was being gentle so did no damage. The problem was easily fixed by using a piece of 2" ID PVP pipe (painted black) which was cut to the proper length to make the eyepiece parfocal with my main observing eyepiece.

Fred