Star Diagonal

[Zuts]

Hi all,

I need to get a 2 inch star diagonal and was thinking of getting the Meade 5000 series dialectric. Anyone have any thoughts on this.

It is for a Nextstar 11 GPS

Thanks Paul

[MikeyB]

For a premium product at a generic price, the Bintel Star Diagonal Quartz would take some beating: $149 in either standard (https://www.bintelshop.com.au/Product.aspx?ID=7255) or SCT type (https://www.bintelshop.com.au/Product.aspx?ID=7256). These are solidly built and work brilliantly.

The Meade (https://www.bintelshop.com.au/Product.aspx?ID=7141), at $309 from the same source, isn't quartz substrate or SCT fitting. Personally, I wouldn't pay double for blue paint and less features!

An SCT diagonal could fit directly to the N11, surely? It certainly did with my N8i. Then you can ditch the standard Visual Back along with the lame 1.25" diagonal.

The only downside of going to a 2" diagonal might be clearance from the mount base. If this is an issue on the N11, you'll need to alter the NexStar slew limit via the handpiece, to reduce the maximum vertical angle.

The William Optics 2" diagonals (and possibly some Lumicons), are supposedly a shorter form factor and might avoid mount base contact problems. I went with the much cheaper Bintel and didn't investigate those alternatives.

I hope this helps and doesn't just confuse matters for you!

[jase]

I used a Televue 2" Everbrite diagonal with NX11. With the Peterson 2" eyeopener visual back you've purchased Paul, you can just about use any 2" diagonal. The NX11 has considerable clearance between the fork arms. In fact, the entire OTA can swing down (do a complete 360 degree loop) and not hit the telescope base. Impressive for a 11" OTA. This makes it easier to transport. Not sure if the new Meade's can do this, but it was one of the reasons I went down the Celestron path at the time. Field portability with such a large aperture/long focal length telescope was excellent. I'm sure the new CPC's are similar.

[Zuts]

Wow, I never saw that one! Thanks for your quick reply.

I was after the meade because it was the (cheapest lol) with dialectric coatings.

Would it change your opinion if i said i could get a second hand one, in very good condition for $190? Meade says enhanced dialectric coatings?

What is the benefit of quartz over a mirror.

Thanks
Paul

[Zuts]

Lol Jase, I dont suppose you want to throw in the Televue :)

Seriously, what is your opinion of the Bintel quartz v the Meade @ $190

[casstony]

I think quartz has no pracitical advantage over other substrates. I've been told that it has better thermal stability, but surely the diagonal will be cooled by the time the scope has cooled. Televue everbrites are not quartz and are considered to be the best money can buy.

[Zuts]

Thanks casstony, that sounds like a very good point.

[g__day]

I use the Bintel and for under $150 its great!

[casstony]

There is also the BK7 dielectric at Bintel for $95. Unless there are different standards of manufacturing between the BK7 and quartz (such as a different number of layers of dielectric coating) I can't see why one would pay an extra $54 for the quartz diagonal. It would be interesting to see a comparison between the two Bintel dielectric diagonals.

[Zuts]

Hi All,

Thanks for your help. I got the Bintel mirror dialetcric coated, 2 inch for $95. Quartz is probably only useful in areas of extreme temp changes and visually probably not much difference to the meade. Probably not worth double.