What's the best 2" Diagonal for a Tak FC 100-DC, f7.4?

[SuburbanMak]

A question for the hive mind...

What's the best 2" diagonal option for an f7.4 Tak 100 DC?

Having recently acquired a FeatherTouch focuser which came attached to the lovely new-to-me FS60Q  (purchased in immaculate condition courtesy of @astro_al )  I've got this up and running on my Tak FC100-DC & after a bit of allen-key fiddling it's now working perfectly.  In 1.25" mode, the FC100 DC was working beautifully with the Tak Prism, which makes me think that at f7.4 I am fine with a prism. 

My 2" diagonal today is a TS-Optics 99% Dielectirc mirror, originally purchased as part of an ST80 2" conversion. It's giving lovely views and although not a "budget, budget" option I am thinking that it may be the weakest link in my optical chain. 

So, the questions are:

Do I need to upgrade at all, will I notice the difference?    

If I do upgrade am I best with a Prism or a Mirror and if so which is the best fit with this scope?

Options seem to me to be from the Tak 2" mirror, Baader 2" BBHS Mirror or Prism, Televue Everbrite.  Main considerations are 1) optical fidelity & 2) weight. 

 

 

 

 

Edited February 15 by SuburbanMak

[mikeDnight]

I use a 1.25" Baader Zeiss BBHS prism which actually has an oversized prism. This means that with a 2" nose and 2" click-lock, you can use  30mm 70° Ultraflat eyepiece  (UFF) and still get a completely full field. Alternatively you could use a 2" dielectric such as the Altair 2" with click-lock.

 

Or you could stay totally Tak as JeremyS has.

Edited February 15 by mikeDnight

[Space Hopper]

I use the Baader BBHS mirror diagoal, with 2" clicklock which has always impressed me greatly.

Beautiful build quality, and excellent performance. Item number is #2456115

The bad news is its gone up in price by a crazy 50% since i bought mine 4 or 5 years ago

Nearly as good, but for a bit less is the white bodied non BBHS version #2956100. Incredible build quality again.

https://www.firstlightoptics.com/diagonals/baader-clicklock-2-dielectric-star-diagonal.html#about_this_product

But whether it be mirror , or prism, you won't go far wrong with Baader.

[SuburbanMak]

43 minutes ago, mikeDnight said:

I use a 1.25" Baader Zeiss BBHS prism which actually has an oversized prism. This means that with a 2" nose and 2" click-lock, you can use  30mm 70° Ultraflat eyepiece  (UFF) and still get a completely full field. Alternatively you could use a 2" dielectric such as the Altair 2" with click-lock

Thanks @mikeDnight - this is a good & potentially money saving tip! 

[Nicola Fletcher]

59 minutes ago, Space Hopper said:

I use the Baader BBHS mirror diagoal, with 2" clicklock which has always impressed me greatly.

Beautiful build quality, and excellent performance. Item number is #2456115

The bad news is its gone up in price by a crazy 50% since i bought mine 4 or 5 years ago

Nearly as good, but for a bit less is the white bodied non BBHS version #2956100. Incredible build quality again.

https://www.firstlightoptics.com/diagonals/baader-clicklock-2-dielectric-star-diagonal.html#about_this_product

But whether it be mirror , or prism, you won't go far wrong with Baader.

I use this one for my FC100DZ and really like it too.

[Stu]

@SuburbanMak what is the lowest power/widest field eyepiece you use? Do you do much widefield observing?

I ask because the T2 versions of the prism or BBHS mirror diagonals from Baader are much lighter and with a shorter light path than the 2” versions, yet still show only limited vignetting even with something like a 31mm Nagler. I found most benefits to be at higher powers, although others may disagree, so the clear aperture is less of an issue in these instances.

 

[JeremyS]

If going larger than 1.25 inch diagonal, I’d go for a mirror (to avoid longer path length through a bigger prism). BBHS is my preference. You could cut cost and weight with T2 size.

The Tak 2-inch mirror is super too, but I generally like the Baader Clicklock

[SuburbanMak]

3 minutes ago, Stu said:

@SuburbanMak what is the lowest power/widest field eyepiece you use? Do you do much widefield observing?

Hi @Stu  - the widest I am likely to use in the FC100 is the Stella Lyra 30mm UFF (APM clone).   With the TS 2" mirror I am having to drop the diagonal back about 5mm to achieve focus with this EP currently, not ideal but secure & workable.   I'd love to get a diagonal that doesn't require this so maybe a somewhat longer lightpath might actually help. 

[Space Hopper]

Worth noting that the Clicklock bit itself actually adds around 10mm to the lightpath, so yes, that could be helpful.

The flipside is of course, it can be detrimental, say if you want to try binoviewing where every mm can count in the focusing challenge. 

[Mr Spock]

Baader Zeiss T2. Works perfectly with the 30mm UFF without any vignetting.

It's already been said, but the biggest difference will be seen at higher powers. It's much easier to see faint features on Jupiter for example than with a mirror diagonal. I have the Baader mirror which is excellent but this prism just takes the next step upwards. I still use the mirror for doubles as I don't see a difference, plus the mirror 2" can take my 42mm LVW.
Prior to this I had the Tak prism and the differences between the two visually are slight, however, the Baader is far easier to use with the clicklock and takes 2" eyepieces whereas the Tak was 1.25" only.

One thing to note is the shorter light path. It's shown here with the 35mm extension but doesn't come to focus with that. I have to use the Tak 80mm which came with the scope.

[DirkSteele]

No real experience with prism diagonals but the best mirror diagonal I have used is the Baader BBHS. Colours have a greater vibrancy than dielectric mirrors and slightly less scattered light around bright objects. Not a night and day improvement but definitely obvious. The biggest surprise was the increase in intensity of the GRS using 4” class scopes.

[Space Hopper]

17 minutes ago, Mr Spock said:

Baader Zeiss T2. Works perfectly with the 30mm UFF without any vignetting.

It's already been said, but the biggest difference will bee seen at higher powers. It's much easier to see faint features on Jupiter for example than with a mirror diagonal. I have the Baader mirror which is excellent but this prism just takes the next step upwards. I still use the mirror for doubles as I don't see a difference, plus the mirror 2" can take my 42mm LVW.
Prior to this I had the Tak prism and the differences between the two visually are slight, however, the Baader is far easier to use with the clicklock and takes 2" eyepieces whereas the Tak was 1.25" only.

One thing to note is the shorter light path. It's shown here with the 35mm extension but doesn't come to focus with that. I have to use the Tak 80mm which came with the scope.

Your scope looks very classy with the Feathertouch and 'More Blue' rings Michael.

And the Baader diagonal adds to that look as well. Very impressive.

[Mr Spock]

2 minutes ago, Space Hopper said:

Your scope looks very classy with the Feathertouch and 'More Blue' rings Michael.

And the Baader diagonal adds to that look as well. Very impressive.

As I head for retirement (four weeks tomorrow) I was determined my last scope would have the best of the best of the best. It is now a joy to use and will last a lifetime (what little I have left ).

[SuburbanMak]

23 minutes ago, Mr Spock said:

Baader Zeiss T2. Works perfectly with the 30mm UFF without any vignetting.

It's already been said, but the biggest difference will be seen at higher powers. It's much easier to see faint features on Jupiter for example than with a mirror diagonal. I have the Baader mirror which is excellent but this prism just takes the next step upwards.

Great information thank you & I have the same 30mm so very good to know!  Also, that does look nice...

[John]

When I want to use a 2 inch diagonal in my Tak FC100-DL I use an Astro Physics Maxbright, which is really a superb item 🙂

Most of the time I use a Baader T2 Zeiss prism though and stick to 1.25 inch format eyepieces.

 

[jock1958]

6 hours ago, Space Hopper said:

Nearly as good, but for a bit less is the white bodied non BBHS version #2956100. Incredible build quality again.

Bought mine off an SGL’r a few years ago and agree about the incredible build quality, love the chunky feel, kerfs on the nosepiece and easy to use click lock. Also it’s the mainstay diagonal for edge to edge views with my 31mm Nagler T5.