1.25 Diagonal - economical suggestions please

[Justin P]

Hi all,

I’m after a little advice please. I have made some recent purchases including a mount and Swift 831, so I’m keen to get (re) started.....
 

Long term my intentions are to have excellent eyepieces and an excellent diagonal - but my budget at this stage can’t cope.

Please could I hear your views on a good - but cost effective - diagonal for an old but well regarded Swift 831........

In addition I need some eyepieces -  longer term the TV, or Pentax range of kit is on my mind - but I’m after something to get started with - something that generates a bang for the buck so to speak. I’m a glasses wearer so eye relief is a must. Viewing will be mainly lunar and planetary - but id like to use the odd wide field too - If my budget permits.

Any opinions / thoughts welcome.

Best wishes, Justin 

[Pixies]

Can you give a little guidance on your budget?

[johninderby]

The Svbony 1.25” diagonal is pretty good despote it’s bargain price.

https://www.amazon.co.uk/Diagonal-Adapter-Refracting-Telescope-Eyepiece/dp/B07GPMX7BN

The StellaMira diagonal is a bit better.

https://www.firstlightoptics.com/diagonals/stellamira-1-25-90-di-electric-diagonal.html

And better still.

https://www.firstlightoptics.com/diagonals/william-optics-125-dura-bright-dielectric-diagonal.html

Or if you  would prefer a prism.

https://www.rothervalleyoptics.co.uk/baader-prism-diagonal-t-2-90-with-focusing-eyepiece-holder-and-125-nosepiece.html

 

 

[cajen2]

The usual advice for a reasonably-priced EP range is BST Starguiders.

Eye relief is right on the edge for you at 16mm.

Edited February 15, 2022 by cajen2

[cajen2]

The Vixen SLV range has 20mm and are very good but over twice the price.

[cajen2]

You could also check out the StellaLyra LER (long eye relief) range

 

[mikeDnight]

Swift are really Takahashi, so I'd suggest you treat your beautiful Swift to a Takahashi 1.25" prism diagonal. These are superb quality and allow for exquisite images with no light scatter.

[Louis D]

2 hours ago, cajen2 said:

The usual advice for a reasonably-priced EP range is BST Starguiders.

Eye relief is right on the edge for you at 16mm.

12mm usable thanks to 4mm of eye lens recession for all but the 25mm which has 17mm of usable eye relief.

[Louis D]

Long eye relief at high power (<1mm exit pupil) isn't a must for an eyeglass wearer unless you've got really strong astigmatism (>2.0 diopters).

As an f/13 scope, it is going to be pretty gentle on eyepieces.  Also, you probably won't want to go much below an 8mm eyepiece to keep the exit pupil above 0.6mm which is already pretty tiny and prone to exposing floaters in the eye.

[Justin P]

23 hours ago, Pixies said:

Can you give a little guidance on your budget?

Sorry for the slow reply - I guess ideally not more than £100 per eyepiece at this stage - I was thinking of two eyepieces and obviously just one diagonal. 

[johninderby]

The Nirvana eyepieces are a real best buy. Not quite as good as Naglers but not far off and a great price.

https://www.firstlightoptics.com/ovl-eyepieces/ovl-nirvana-es-uwa-82-ultrawide-eyepieces.html

[Justin P]

21 hours ago, mikeDnight said:

Swift are really Takahashi, so I'd suggest you treat your beautiful Swift to a Takahashi 1.25" prism diagonal. These are superb quality and allow for exquisite images with no light scatter.

Thanks for this info - it does open up a few more questions.... 

There seems to be a lot of chat on prisms v’s mirror diagonals - having said that if your happy with yours and you think it will suit the swift I think  I’ll go with this.

Incidentally I also have a Tal 100r, I assume it would be good for both ?

thanks justin 

[Justin P]

Just now, johninderby said:

The Nirvana eyepieces are a real best buy. Not quite as good as Naglers but not far off and a great price.

https://www.firstlightoptics.com/ovl-eyepieces/ovl-nirvana-es-uwa-82-ultrawide-eyepieces.html

Thanks for this - I’ll check them out ! 

[johninderby]

I chose the Baader prism for my Scopetech 80. Prisms work best on longer focal length scopes.

 Scopetech and the Starbase scopes are both made by the company in Japan that makes the Starbase scopes for Takahashi. Classic scopes but with the latest optical coatings.👍🏻

 

Edited February 16, 2022 by johninderby

[cajen2]

17 minutes ago, johninderby said:

I chose the Baader prism for my Scopetech 80. Prisms work best on longer focal length scopes.

 Scopetech and the Starbase scopes are both made by the company in Japan that makes the Starbase scopes for Takahashi. Classic scopes but with the latest optical coatings.👍🏻

 

That's a thing of beauty.....

How long is the OTA? I believe the 80 has two f/l options.

Edited February 16, 2022 by cajen2

[johninderby]

The f/15 has an OTA length of 125cm. They also do an f/12 version and Starbase does an f/10.

[mikeDnight]

13 hours ago, Justin P said:

Thanks for this info - it does open up a few more questions.... 

There seems to be a lot of chat on prisms v’s mirror diagonals - having said that if your happy with yours and you think it will suit the swift I think  I’ll go with this.

Incidentally I also have a Tal 100r, I assume it would be good for both ?

thanks justin 

Hi Justin,

  Yes, I couldn't be happier with the Takahashi Prism. I'm pretty sure you'll find it works fine on your Tal too. 🙂

[Roy Challen]

15 hours ago, Justin P said:

 

Incidentally I also have a Tal 100r, I assume it would be good for both ?

thanks justin 

Probably not. The Tal 100R has a bespoke screw on diagonal IIRC. If you mean 100RS, then yes, it'll be fine.

[Justin P]

Ok thankyou all. It is a Tal 100r Roy…. I’ll have a think about this when the swift is up and running !

 

 

[Zermelo]

On 15/02/2022 at 22:54, johninderby said:

And better still.

https://www.firstlightoptics.com/diagonals/william-optics-125-dura-bright-dielectric-diagonal.html

 

If you were taken by that suggestion, FLO have a return at a slight discount:

 

[Justin P]

7 hours ago, Zermelo said:

 

If you were taken by that suggestion, FLO have a return at a slight discount:

Many thanks for this info. Regards Justin 

 

 

[F15Rules]

The Tal 100r I had some years back would take the Tak prism physically, but had only about 30-40mm of travel, which could make focusing a problem...

..but for your 831 (lovely scope, is it adapted for 1.25" diagonals?) the Tak would be a great match as Mike says👍.

Dave

[Justin P]

On 21/02/2022 at 23:04, F15Rules said:

The Tal 100r I had some years back would take the Tak prism physically, but had only about 30-40mm of travel, which could make focusing a problem...

..but for your 831 (lovely scope, is it adapted for 1.25" diagonals?) the Tak would be a great match as Mike says👍.

Dave

Thankyou Dave. So, the .965 to 1.25 adapter is sorted, as is the Tak prism. The 100R is causing me a headache.

As you have identified there is very limited travel on the focuser …. Perhaps the subject of another topic.

Best, Justin.