Dielectric star diagonals

[Inky]

Hi, like most people new to astronomy the more I read and do the more i think i need. I've been wondering if I should replace the diagonal I got with my 127 mak with maybe a dielectric one?? Is this sensible/necessary/a good idea? If so what would people suggest I get for say 50/60 quid ??

[John]

The William Optics one is very popular and nicely made. The optical improvements will be subtle rather than obvious but it's a nice piece of kit and it has a compression ring fitting which marks your eyepieces less than the set screws that the stock diagonals use.

It's a "nice to have" rather than a necessity though, if money is tight.

The main advantages of these diagonals is that they tend to transmit a little more light (eg: 99% v's 95%) and the coatings on the mirror (the dielectric ones) are more hard wearing than standard ones.

[jonathan]

I agree with John, it might just become the nicest part of your scope but as it's the part you interact with the most (changing eyepieces) then it's also one of the most important.  The Williams Optics 2" dielectric diagonal that I have has removable side panels for easy cleaning inside, and has carbon fibre construction which makes it much lighter than a similar sized metal bodied one.  Expensive but the only diagonal you may ever need to buy.  I really miss the brass compression rings if I have to use a cheap scope that my 2" diagonal won't fit (e.g. ST80), like I miss the saddle clamp on my NEQ6 when I use smaller mounts that only have screw fittings for the vixen dovetail clamping.

[Mem]

I agree with the above members, the view it provides is a subtle change, and combined with quality eyepieces does make a big difference, I also agree the William optics diagonal it's the one I would recommend as I had one on my sct and also on my zs 71, also I can see why the 2" is popular but I have always bought the1.25", it's more affordable and no difference in quality it all depends if you want to go down the 2" route, the 2" also comes with the 1.25 adapter.

[sandyshaw]

Generally speaking the Skywatcher diagonal is pretty good and is the improvement of the diagional upgrade worth the money that could be better spent on other parts of the telescope?

[CodnorPaul]

Changed mine for the Celestron XLT one and didn't really notice a big difference in viewing quality - what I do get is a bigger FOV with 2" EPs and a much better build quality.  Definitely worth the upgrade for me BUT don't expect the universe to open up in front of your eyes - the stock supplied Celestron one, and I assume the stock Skywatcher one, do a decent job as it is

[Inky]

Thank you for your answers. It looks a nice to have and might have to wait till I have a few more EP's. Cheers