Willams Optics 2" Dielectric Diagonal (SCT)

[M4lcs67]

I have decided that I would like the added visual expanse that having a 2" eyepiece would give, and that obviously means getting a 2" diagonal. I have been on the lookout for a couple of weeks now, and after much deliberation and also a recommendation from Martin @ FLO, I am really leaning towards this,

http://www.firstlightoptics.com/diagonals/william-optics-2-dielectric-diagonal-with-sct-adaptor.html

As well as wishing to have a good quality diagonal, I need one that is a screwfit and not a pushfit, so there is 100% no chance of it falling out of the back of the scope. That did happen to me the other week with my supplied diagonal working loose and falling to the ground with my brand new Hyperion eyepiece still attached. Luckily there was no damage to either, but I want to be sure that I doesn't ever happen again. Thats why I want a screw fit diagonal, so it is physically attached. This diagonal has a push fit end to it, but it also has the SCT adapter as well.

Also being a huge fan of Baader eyepieces I was looking at the Hyperion Aspheric 36mm, but Martin said that they are all but unobtainable and have been for quite some time. So perhaps look at the 31mm instead. Has anyone else got this eyepiece? I really would like to have a larger ep that will give wider views of the sky and I think this could do the trick.

Thanks for your comments/opinions.

[E621Keith]

Your C925 is mounted on a GEM. Are you sure you want a screw fit diagonal? Trying to reorientate a screw fit diagonal can be quite annoying.

Have you consider using a compression ring visual back or a Baader click lock visual back?

[M4lcs67]

Hi Keith,

I hadn't considered either as I don't know what they are. I did think that just slackening off the lock ring and re-orientating the diagonal would have been sufficient? Are these two other methods 100% failsafe?

[E621Keith]

They are not 100% fail safe, but I have never had problem with them. I just think constantly tightening and untightening may wear out the visual back thread.

The safety undercut usually prevents push fit diagonal and eyepiece from falling out, even if it wasn't tighten sufficiently

[alanjgreen]

I have a 31mm Aspheric and I really like it.

I use it as my low power finder eyepiece (CPC800 has 2000 focal length so 2000/31 = x64mag)

The view is very sharp and the eyepiece has a large eye relief which I find comfortable with/without my glasses on. It is perfectly capable to resolve many double stars without the need to change to more power.

Alan

[M4lcs67]

Hi Keith,

So you would still need to have the visual back still attached? I thought that because if you were using a 2" diagonal it would screw directly onto the thread that sticks out of the back of the scope. Although thinking about it logically, by doing it that way you would probably wear the thread out on the scope itself. It would be a damn site cheaper to replace the visual back if that wore out. The safety undercut that is on my Hyperions. Is that a safety device on all Baader stuff then?

Alan,

That is good to know. I am a glasses wearer now, having not had to wear them before, so being able to leave them on will help. Constantly chopping and changing would become rather tedious after a while.

[glowjet]

Most of all the good quality makes have an undercut, I have a Williams 2" Quartz push fit diagonal which once locked into the compression rings of the Moonlite focuser does not move, neither is there any chance of my Hyperions falling out of the diagonal either, with the under cut, whether used in 1.25" or 2" mode, you will also find Williams have introduce a stop flange in their 2" diagonals to prevent such as the Hyperion range accidentally touching the mirror, if you use your eye pieces with other makes of 2" diagonals without such a stop, Baader do a special stop ring with compression fittings, just for this purpose

John.

[RichieP]

Plus one for the annoyance of having to reorient a screw on SCT diagonal, especially when it gets cold and the metal contracts.

[fondofchips]

I have just bought the Revelation 2" diagonal, recommended by SGL members that is the same quality as the William Optics: -

http://www.scopesnskies.com/prod/Revelation/quartz/astronomy%20-accessories/sct/mirror-star-diagonal/dielectric.html - £81.49 posted.

The other SCT version is £88.99 posted.

Also purchased a Baader Hyperion 68° eyepiece 13mm, very impressed with the quality, not tried it yet but it is noticeably heavier than my other 1.25" eyepieces.

Weighed with kitchen scales Baader 13mm 2" approx 400g & the largest 1.25" eyepiece I have Bresser 32mm 175g.

With the 2" diagonal & the Baader eyepiece you will have to reset the scope balance.

[fondofchips]

Described the diagonal incorrectly - the cheaper one is the correct one I think.

Somebody will know exactly what is needed, I do agree that the screw thread would be a pain, I have got into the habit of double checking the holding screws only takes a second or two.

Earning the money to replace damaged gear takes longer..........

[Dunkster]

Malc, I'd recommend one of these as it makes it really easy to rotate the diagonal, even with gloves on http://www.365astronomy.com/2-clicklock-clsc-eyepiece-clamp-for-sc-telescopes-p-1911.html

[M4lcs67]

Hey, Dunk,

Thanks for the heads-up on this. Do you have it then? Looking at the Baader system, it appears to have the clamp type set-up as alot of the other ones do, where you tighten the lockscrew, but it doesn't gouge directly into the metal. As you tighten the screw, the internal collar closes around the diagonal barrel and grips it right around.

There is so much choice again. Nigh on impossible to choose sometimes.

Looking at things, this would be the diagonal to go with it then?

http://www.365astronomy.com/2-clicklock-dielectric-diagonal-mirror-p-654.html

Well I have a shed load of ideas now. It is just a case of digesting it all and coming to a decision.

ps

Hope you are doing ok. Been out lately????

[Dunkster]

Yeah, I have it's wider sibling - the C11 and C14 have a 3.25" diameter thread on the back instead of the 2" thread on the smaller SCTs - but functionally they're the same. It is compression ring, but like you noticed more of a clamp than a tightening ring. Absolutely rock solid with the diagonal and ES82 30mm (1kg!) along for the ride. Not sure I'd fancy carrying my ota upside down with it like in the promotional shots though

For the diagonal itself, you can use any standard 2" diagonal, but the click lock diagonal is the obvious choice if you decide you like the click lock system.

Btw, 2" EPs is a natural progression but comes at a price

[E621Keith]

Hey, Dunk,

Thanks for the heads-up on this. Do you have it then? Looking at the Baader system, it appears to have the clamp type set-up as alot of the other ones do, where you tighten the lockscrew, but it doesn't gouge directly into the metal. As you tighten the screw, the internal collar closes around the diagonal barrel and grips it right around.

There is so much choice again. Nigh on impossible to choose sometimes.

Looking at things, this would be the diagonal to go with it then?

http://www.365astron...rror-p-654.html

Well I have a shed load of ideas now. It is just a case of digesting it all and coming to a decision.

ps

Hope you are doing ok. Been out lately????

No, that's not how the Baader works. You are thinking of a compression ring system, but Baader click lock uses a twist lock mechanism. You turn the adapter to lock the eyepiece/diagonal. That thumb screw like extrusion is a lever to give you more leverage when you turn the lock ring.

[M4lcs67]

Thanks again, Keith. I know what you mean now. I take it you could still use different makes of diagonal with a 2" barrel? For example the Baader Clicklock 2" clamp and the Williams Optics 2" Dielectric diagonal or something of that sort?

[E621Keith]

yes, it is still a 2" push fit connection

[faulksy]

ep wise i use a 40mm sw aero and find this pin sharp right across the fov