Going to the Refractor dark side

[pragmatist]

Ok so finally after being away from the hobby I have decided I want an Apo triplet refractor.

i am mostly visual on planets, double stars etc but would also like to dip my toes into the imaging pool at some stage. I would ideally like 100mm ish and have around £1500 to play with for the OTA.

Ive been looking at Altair's offerings and also the WIlliams 102 GT at F6.9

Any others I should be considering?

Thanks,

Matty

 

 

 

 

 

 

[John]

If you had not mentioned imaging I'd be suggesting that you look out for a pre-owned Takahashi FC-100 in the F/7.4 form. About as good as a 4" apochromat can get IMHO.

As a "visual only" person I'd tended to stick with doublets for their faster cool down.

 

 

[LightBucket]

You should seriously look at the Skywatcher Espirit Pro 100mm, superb scopes, but with the Flattener and the optics check and certificate that FLO provide (which is well worth the extra £75) it will be a tad over budget..

https://www.firstlightoptics.com/esprit-professional-refractors/skywatcher-esprit-ed-100-pro-triplet.html

[RayD]

+1 for the Esprit.  I have the 100mm and absolutely love it.

[Owmuchonomy]

What is it you intend to image?  You may not necessarily 'need' a triplet depending upon your targets and technique, for example narrow band.  What capacity is your mount?  I used to own the Altair 102 triplet but it had to be returned.

[Chris]

In your price range I'd probably go for one of the certified/tested Esprit 100 from FLO also.

https://www.firstlightoptics.com/esprit-professional-refractors/skywatcher-esprit-ed-100-pro-triplet.html

The above is just a general opinion though, as mentioned it would be handy to know what mount you plan for it, and what objects you want to image.

 

[pragmatist]

It would be 80% visual but imaging wise prob planets and open clusters and double stars 

[pragmatist]

1 hour ago, LightBucket said:

You should seriously look at the Skywatcher Espirit Pro 100mm, superb scopes, but with the Flattener and the optics check and certificate that FLO provide (which is well worth the extra £75) it will be a tad over budget..

https://www.firstlightoptics.com/esprit-professional-refractors/skywatcher-esprit-ed-100-pro-triplet.html

I forgot about the Esprit, yes I did include that in my possible list.

[pragmatist]

1 hour ago, LightBucket said:

You should seriously look at the Skywatcher Espirit Pro 100mm, superb scopes, but with the Flattener and the optics check and certificate that FLO provide (which is well worth the extra £75) it will be a tad over budget..

https://www.firstlightoptics.com/esprit-professional-refractors/skywatcher-esprit-ed-100-pro-triplet.html

My worry also is that F5.5 is pretty fast for visual though I am inexperienced in this area as I've always just had SCT's

[Chris]

13 minutes ago, pragmatist said:

It would be 80% visual but imaging wise prob planets and open clusters and double stars 

Well just focusing on the 20% imaging for a moment, especially with planetary and double stars you'd be better off with more aperture for the added resolution. Something like an SCT, Newt, or Mak. 

If you're 80% visual and just 20% planetary, maybe an ED120 f/7.5 would be a good compromise, plus you'll have change for a nice Moonlite focuser

All depends on the mount being able to handle this though? 

[michael.h.f.wilkinson]

Agreed that on planetary imaging, a big aperture SCT totally outclasses a smaller refractor. There is no contest between my 80mm triplet and my C8 on planetary imaging

[newbie alert]

16 minutes ago, michael.h.f.wilkinson said:

Agreed tha ton planetary imaging, a big aperture SCT totally outclasses a smaller refractor. There is no contest between my 80mm triplet and my C8 on planetary imaging

I've had my sct for a couple of years and delighted with the views and images..ive now got a 80ed which first light I thought I'd try on the moon and was quite shocked at the clarity...

[Macavity]

I think I was more in awe of expensive refractors (and their owners!) until I had actually read
more about some *actual* measurements of optical quality / adjustment of said refractors.
(It would seem that "indifference" is still a possibility and simple BAD adjustment is as well?)

That said, I am "blown away" by the (subjective) performance of a humble ED66 (semi) APO!
To me it seems evident that the added *complexity* of TRIPLET APOs (cell, collimation etc.)
would merit a detail knowledge (certificates!) of the individual  performance of the Beast... 

[Stu]

Certainly buying a cheap triplet seems a route to problems, for imaging in particular. FLO's testing and certification offer seems worth going for.

Agreed though, think about whether an Apo frac is best suited to your needs. Personally I love them, and if my only scope was a high quality 4" apo, either doublet or triplet then I would be happy.

An SCT, say an 8" will give higher resolution and more colourful views, and much better planetary images but will be more susceptible to cooling, seeing and collimation issues. I find that fracs give cleaner star shapes and personally enjoy splitting doubles with them more than SCTs.

Here is an idea. On the used market you could get both a 120ED and an 8" SCT for under your budget, what's not to like?  

[michael.h.f.wilkinson]

Just found some older data

APM 80mm Triplet:

C8

 

[ollypenrice]

1 hour ago, pragmatist said:

My worry also is that F5.5 is pretty fast for visual though I am inexperienced in this area as I've always just had SCT's

On a high quality instrument the fast F ratio can be great for visual, giving a huge FOV in a long focal length eyepiece. Rosette, entire Veil complex, Double Cluster with Stock II... lots to enjoy in widefield!

Olly

[michael.h.f.wilkinson]

21 minutes ago, Stu said:

Certainly buying a cheap triplet seems a route to problems, for imaging in particular. FLO's testing and certification offer seems worth going for.

Agreed though, think about whether an Apo frac is best suited to your needs. Personally I love them, and if my only scope was a high quality 4" apo, either doublet or triplet then I would be happy.

An SCT, say an 8" will give higher resolution and more colourful views, and much better planetary images but will be more susceptible to cooling, seeing and collimation issues. I find that fracs give cleaner star shapes and personally enjoy splitting doubles with them more than SCTs.

Here is an idea. On the used market you could get both a 120ED and an 8" SCT for under your budget, what's not to like?  

Totally agree that a combination of a frac and an SCT is near perfect. The APM 80mm F/6 I have is great for wide-field viewing, and is my stalwart solar imaging scope, the SCT is my general purpose visual scope and planetary and lunar imaging scope of choice. My only wishes (for now ) are either a big Dobson, or bigger SCT, and something like a 5 or 6" achromat for larger scale solar images (using extreme narrowband, so no need for APO). 

[RayD]

Or of course, as I have, go for both 

 

[Chris]

1 hour ago, michael.h.f.wilkinson said:

Just found some older data

APM 80mm Triplet:

C8

 

Hi Michael, just had a thought! Would it be possible to crop the 80mm Triplet image to the same image scale as the C8? I'm thinking it would be a good and accurate test of resolution and sharpness perhaps?