Best diagonal

[LewisM]

Who manufactures the most reliably consistent maximum transmission/least light loss/scatter 2" or 1.25" diagonal?

Are Tak diagonals worth it? TV (I had a 1.25 TV, and it was nice)? AP?


Need the best I can obtain to suit my new Takahashi visual arrival, and I think the Meade I currently have (generic rebranded Chinese) won't give me the best view possible - good, but no cigar

Yes, it's pedantic, but...

[Larryp (Laurie)]

I have always used Televue 2" dielectric mirror diagonals-cannot fault them.

[blink138 (Pat)]

i have a 2" takahashi diagonal too lewis if you want to lend it?
pat

[RB (Andrew)]

On my TOA 130 (and all my other scopes) I use a TeleVue 2" Everbrite Diagonal.
Beautiful quality, never needed any other.

[SkyWatch (Dean)]

If you want the best, then the TV or Tak are probably the way to go. However, I use a GSO dielectric quartz one: the specs (if you can believe such things) give better figures than either TV or Tak (GSO claim 1/15 wave!), and it is very well made: at 1/4 of the cost of the Tak...

- Dean

[brian nordstrom (As avatar)]

Lewis there is no shame in owning and using the GSO's , I have one in my SKY90 a GSO 2 inch Quartz type and when I was in Darwin 4 of us did a blind comparisim using 3 telecopes , My sky90 , a np127 TV APO and my 127mm iStar achromat , we set up on a good dry season night and one person shifted the 3 diagonals , My GSO , a TV Everbrite and an AP Maxbrite , all 2 inch between all 3 scopes at random , he kept notes as to which diagonal was in which scope and our comments and to be very honest here ,,,, none of us could see the slightest bit of difference in all three . It sure was fun reading these over a beer later on colourful reading .

Objects were , moon , Jupiter , Mars , Alpha Crux triple star system and the eta Carina nebular , all eyepieces were TelVue Naglers , a 22mm ,14mm and 6mm .

There is mystique in owning a top shelf diagonal for sure , but we found that the difference in the field is neglegable at best and highly suggestive with not one diagonal any better or worse than the other 2 , but hey its your money and if you want an AP , TV or Tak diagonal go for it .

I like my GSO Quartz , its very , very good .

Brian.

[PlanetMan]

I would have to concur with Brian regarding the quality of the mirrors in the diagonals. Indeed, from my experience images seemed slightly better in my quartz GSO than an everbrite. However, this was a memory comparison over different nights and I wouldn't bet my house on this.

Now - the real question is what actually makes the TV Everbrite better and why everyone buys them. They are IMO as follows:

1) One piece design - when you have that 1k$ 21mm Ethos or 31T5 terminagler in your diagonal and your EQ mount turns onto a horizontal angle you have complete peace of mind the nose won't twist and down goes the EP. You can try threadlock or glue on GSO diagonals but for 100% peace of mind you can't beat a one piece design.

2) Durability - this is both on the construction of the actual diagonal and coatings on the mirror. Basically, you buy the everbrite and that's it for life.

3) Resale value - TV products tend to hold their value better than virtually any other gear

Having said all of this does not down play the excellent piece of equipment the GSO quartz diagonals represent but merely highlighting the main benefits of the Everbrites.

[LewisM]

Thanks everyone. I'd like to TRY Tak, just to "stay with the team" and see how they are. I know what the TV's are like, having had a 1.25" one.

Will keep looking for a second hand one, or shell out the deniro to Claude.

[LewisM]

Originally Posted by blink138

i have a 2" takahashi diagonal too lewis if you want to lend it?
pat

Thanks Pat - I might take you up on that gracious offer.

[Don Pensack]

The Vernonscope quartz dielectric ranks right up there.
Also the Astrophysics Max Bright.
These for mirror diagonals.
For prisms, Baader and Zeiss.

[Renato1 (Renato)]

Darned if I can see much by way of difference between my Celestron, Meade, Televue, William Optics, GSO and some no name brand diagonals. Certainly not on DSOs though sometimes, if I try hard, I think I can imagine a slight difference on planets.
Regards,
Renato

[N1 (Mirko)]

Originally Posted by PlanetMan

I would have to concur with Brian regarding the quality of the mirrors in the diagonals. Indeed, from my experience images seemed slightly better in my quartz GSO than an everbrite. However, this was a memory comparison over different nights and I wouldn't bet my house on this.

Now - the real question is what actually makes the TV Everbrite better and why everyone buys them. They are IMO as follows:

1) One piece design - when you have that 1k$ 21mm Ethos or 31T5 terminagler in your diagonal and your EQ mount turns onto a horizontal angle you have complete peace of mind the nose won't twist and down goes the EP. You can try threadlock or glue on GSO diagonals but for 100% peace of mind you can't beat a one piece design.

2) Durability - this is both on the construction of the actual diagonal and coatings on the mirror. Basically, you buy the everbrite and that's it for life.

3) Resale value - TV products tend to hold their value better than virtually any other gear

Having said all of this does not down play the excellent piece of equipment the GSO quartz diagonals represent but merely highlighting the main benefits of the Everbrites.

I agree with all of the above. I have replaced my 1.25" WO diagonal with an Everbrite for different (initial) reasons. The WO is actually pretty good overall, but I had 2 issues with it: vignetting eyepieces (especially the 24 Pan) and a snagging compression ring. Both things I was not prepared to tolerate forever (I did for 2 years) and the Everbrite solved both.

Despite having a greater internal diameter, the Everbrite is smaller than the WO. The recessed area where it connects to the visual back of the refractor is cylindrical not conical, meaning that is is held in place more precisely and securely.

My only complaint about the Everbrite is the thumb screw. It stands out further than on other units and collides with my nose at some observing angles.

In terms of brightness, I can't say I've seen a difference though.

[acropolite (Phil)]

+1 for the GSO quartz, keep the extra money for your next fad...

[AG Hybrid (Adrian)]

Which ever you choose, don't forget to open them up and flock or paint the insides (minus the mirror of course). Pretty much all of them have reflective surfaces on the inside and are reminiscent to glitter balls. Some simple flocking material or black board paint will provide a small improvement to contrast.

[brian nordstrom (As avatar)]

Good advise Planet man , but my GSO Quartz actually has 3 tiny grub screws hidden inside , coming upwards to lock the eyepiece holder so it cant undo , also my sweet TMB 2 inch Dielectric has 3 inside as well but coming in from the sides , hidden under the side plates these are tiny only a about 1.5mm allen key.
I only found these by accident one day , being the consument tinkerer .

Brian.

[Octane (Humayun)]

Hey Lewis,

I have a 2" Takahashi diagonal you're welcome to borrow.

I don't know if if will fit your Baby "Q", though. It was designed specifically for the 106N.

H

[Kunama]

Personal preference only but after trying the Tak 1.25", GSO 2", Baader 2" and a few others, I decided on the Baader 34mm Zeiss Prism, it is just beautiful and seems to really suit the Fluorite Taks.

[UniPol]

I think I've owned most brands (mirror & prism) over the years and can honestly say that I've really not noticed any appreciable difference in their performance. I currently own TeleVue and Takahashi diagonals mainly because of their build quality, compatability with the same branded eyepieces, telescopes and the expectation that they will perform well and have a good resale value. My Unitron 50 year old plus prism diagonals certainly perform very well to this day.

I have mentioned on this forum in the past that there is really only one way to test if a diagonal is up to the mark at least on an amateur level and that is to just put your eyepiece in the drawtube and just look straight through so to speak, ah la Galileo Galilei style.

[brunono2 (Brian)]

Lewis

BEFORE you buy a diagonal I suggest you read the attached cloudy nights diagonals Review- Baader T2+ 2 inch prism feature highly

Cheers

Bruno

[LewisM]

Thanks all.

I have committed to buy Tony's 1.25" Tak prism diagonal, so will give that a crack for a while.

H, I may come down and tak ..errr. TAKE you up on that kind offer (saves any postage issues with Pat's). The FSQ85 has both the 2" and 1.25" visual backs, so shouldn't be an issue.

I tried the Meade through the FSQ with the Tak 2" back, and I can say that's a VERY well designed and EXTREMELLY solid clamping ring! No movement whatsoever. I have had diagonals come loose in GSO, SW and Vixen compression rings, but no way on this one. The 1.25" "click-lock esque" of Tak's is just plain solid as a rock too.

I hated the Vixen compression ring so much I put a Baader Clicklock with Vixen adapter on it. Like their adverts show, I could pick the OTA via the diagonal if i were so stupid to try it