star diagonal help

[Jim]

Hi,

i have a Sky Watcher 150PRO mak and need a star diagonal....is it worth all the extra to get a dielectric or is a normal one good enough....I wanna spend £40 max really unless it really is worth the extra??

Thanks,

J.

[barkis]

The cost will be more than £40 surely?

Are you getting a 2" or 1.25".

Personally, I would make do with an ordinary Diagonal.

Ron.

[perrin6]

I suppose once you've bought a dialectric diag. you won't ever have to buy one again if you look afer it (I expect they are 'lasters' but I don't really know),

[Jim]

no i meant £40 for a new one!

the dielectrics are around £80 - is it worth it - I see the difference is 90% reflectivity for normal and 98% for dieletric....just wondering if it will make much difference to me?

thanks.

[KevG]

I have a standard, plus a dielectric & tbh cannot tell the difference between them

[Jim]

thanks - can you recommend a normal one?

cheers.

[astroimpulse]

FLO do a cheap Celestron Diagonal for £36

Diagonals - Celestron 1.25" 90 degree Erecting Prism

[Jim]

thanks, whats better a prism or mirror design?

[sixela]

There's something else a pure dielectric diagonal gets you, other than the reflectivity: the coatings last Forever (plus one day), and they're extremely scratch-resistant. In my book, that alone is worth the price of admission.

[michael.h.f.wilkinson]

I exchanged my Celestron 1.25" diagonal for a WO 2" dielectric, and the difference is very noticeable for two reasons: first the 99% vs 90% transmission, second, the surface is flatter over a larger area, yielding sharper, crisper results at high magnification. I got my WO for 99 Euro, definitely more expensive than 40 pounds, but money well spent.

[astroimpulse]

I wouldn't touch the Celestron as a new diagonal, personally (linked to it for OPs budget reason).

I'll be getting (likely) one of the WO dielectrics as soon as cash flow permits.

[Jim]

so you would touch the one you recommend?

right....???

[astroimpulse]

No...I found that one for your budget. And it's probably as good as it gets new for £40 (I'm guessing).

If I was buying new (which I will be) I wouldn't spend £40 on a diagonal. I'll stretch a wee bit to £100ish and that will be a good start I think (for myself). I don't want to scrimp on a very important part of the optical train after spending so much on my scope.

But like I say...I was showing you that as it fitted your budget

Of course secondhand diagonals come up all the time for your budget. Have you seen U.K. Astronomy Buy & Sell ? Some good deals on there from day to day.

BTW: When my scope arrives it will have the Celestron diagonal lol. But it's thrown in to tide me over until I purchase a 2" dielectric.

[red dwalf]

i had a 1.25" celestron diagonal which came with the scope, i then bought a 1.25" william optics dielectric diagonal and compaired the two like for like, just looking through the diagonal in daylight you can see that the william optics one was so much brighter and clearer than the celestron offering, also look great and if you can get one second hand all the better.

[John]

The funny thing about diagonals is there don't seem to be many (any ?) mid-priced products. You have the low cost Skywatcher / Celestron / Meade / noname standard issue ones which go for £30 or so new, often much less used and then there is a jump straight to the likes of the William Optic's 1.25" dielectrics at £60.

I did come across this dielectric one at just £10 over your budget:

GSO Revelation (GSO) 1.25" fit deluxe CNC mirror star diagonal

[astroimpulse]

Good find John

[E621Keith]

The dielectrics ones will worth the extra money.

I had a normal 1.25", and bought a 2" Celestron XLT diagonal in Astrofest two years ago. Since then, I haven't used the 'normal' one at all, the XLT coated ones does appears brighter than the normal type, and the mechanics feels a lot better. (such as compression ring vs screw, the housing feels more substantial etc...)

[Jim]

Ahh great - I just bought the dielectric one John found!

Hey thanks for your help guys.......I hope I get it read some bad things on here about that shop!! scopes n skies.......HeHe....fingers crossed anyhow!

[John]

Ahh great - I just bought the dielectric one John found!

Hey thanks for your help guys.......I hope I get it read some bad things on here about that shop!! scopes n skies.......HeHe....fingers crossed anyhow!

I'd be interested to know what you think of it - it seems pretty decent for the price

Scopes N Skies seem to have been improving their service lately - I've bought a few things from their "Astroboot" section lately and they have come through fine.

Might be worth giving them a ring to check that your order is OK and the items are in stock - the "human touch" often works I find

[MartinB]

In terms of improving quality of image I've found upgrading the diagonal to be pretty disappointing. However, I would recommend a dielectric on the grounds of durability alone. Diagonals have a busy life, the mirror is very dust and dew prone and, given that they are fairly close to the focal point the grime does make a difference. You can be much more relaxed cleaning a dielectric and in the long run it will save you money. Sounds like you have purchased well. Lets hope SnS get their act together.

Who reckons it will be in stock?

[Jim]

lol! apprently it's "in-stock for immediate dispatch!".... Hmm everything on their site is....must be a HUGE warehouse huh!!

[DeadMan]

It is massive and just down the road from me