Diagonal newbie help?

[saturn10]

Hello everyone,

I have a stock meade 1 1/4" diagonal prism for my meade 8" lx90.

I would like to upgade this to a mirror perhaps quartz dielectic.

When viewing through a prism or mirror what is the difference in image position (upside down, left to right etc)?

thanks,

Rob

[Peter Drew]

A diagonal prism/mirror as long as it is a standard 90 degree unit will give a normal upright image but with left to right reversed. This will appear different however if the diagonal is turned for convenience in its holder. The stock diagonal is quite adequate, you may not notice a great improvement at F10 with an upgraded one but it would be nice to have.

[damnut]

Hi Saturn10,

I have dielectric, uhtc, and bog standard 2" diags, cannot really see much difference. Like the dielectric in the SCT appears to transmit more light & sharper image. May just be my old eyes! :-),

[saturn10]

Thanks for the advice.

Is there an improvement with a 2" over 1 1/4"?

[John]

Thanks for the advice.

Is there an improvement with a 2" over 1 1/4"?

Just that it gives you the ability to use 2" eyepieces as well as the 1.25" ones. The 2" format eyepieces can deliver a much wider field of view at low power.

It's quite common to have a mix of eyepiece sizes - 1.25" for medium to high power viewing and a 2" or two for lower power, wide angle viewing.

[cyg]

Hi Rob, I agree with John, the 2" diagonal gives the advantage of allowing 2" eyepieces for low power wider field views. But I still use the 1.25" eyepieces when observing anything needing reasonable magnification. I went for the standard push in diagonal, which ment I also had to buy the 2" adapter, but it means I can add a filter to the diagonal and change eyepices without moving the filter.

John

[saturn10]

Thanks for your help.

The 2" with adaptor for 1 1/4" might be best.

I have seen some for about £90 quartz dielectric Revelation.

Are these ok or do I need a TV.

thanks,

Rob

[cyg]

I have the Revelation and it appeares OK to me (for the cost) but I'm sure the TV is the proberly better product.