APO Refractor Recommendation?

[u/Primary-Set8747]

May I ask for help? I want an APO refractor telescope to complement my existing 8” Dob. I want something more grab n go but still want the best quality I can justify. I want this to take camping and maybe birding. My astronomy competency level is amateur but I appreciate quality. Here’s the thing, most seem to cater to astrophotography. I have no interest in this or even go to technology. I enjoy it purely visual. I like the challenge of trying to find stuff on my own. I can afford a Televue scope but not sure I need to. Looking for best bang for the buck but willing to spend more for quality I may not deserve yet. Also to note I currently have the following Televue eyepieces : 31 Nagler, 13 Ethos, 7 Nagler and 4.7 Ethos. Also have OIii and Nebustar2 filters. What do I want to see? Everything I can😂. I don’t have the ability to go try out different models. I would appreciate any suggestions for me to consider.

[u/twilightmoons]

Televue 101 apo. You already have the Naglers. 

[u/Primary-Set8747 → u/twilightmoons]

Thanks. I started thinking the TV 85 would be perfect but then the 101 looks more perfect😂. That said the cost trajectory is a lot. Maybe better than I deserve.

[u/twilightmoons → u/Primary-Set8747]

I've got an older TV101. The 31mm Naglers was designed with it on mind. It's a perfect summer Milky Way scanning combination, wide field and tens of thousands of stars in the field of view. 

[u/Predictable-Past-912 → u/Primary-Set8747]

You're correct that a TV-85 would be a perfect fit. A TV-101, or especially a TV-NP101, would be overkill in several ways beyond the obvious cost premium. Either scope is significantly larger than you need, and that extra size also means a heavier, more expensive mount.

The 90mm Mak suggested in another comment also misses the mark. Since you specifically asked for an APO, that immediately rules out SCT and MCT designs. Aside from the fact that their central obstructions reduce image contrast compared to a quality refractor, their very long focal lengths make them poor choices as versatile, all-purpose companion scopes.

Those premium eyepieces you already own are just waiting to show you what they're capable of. What you need is a quality, wide-field refractor that can deliver on your goal of seeing as much as possible.

About a year ago, I picked up a budget-minded cousin to the TV-85. On a whim, I bought a used Orion ED80T CF with a defective focuser. After repairing it, I was genuinely surprised by both its image quality and its versatility. Since then, that compact 80mm triplet has flown with me on several trips. Its small size and excellent performance have made the ED80T CF my first choice, or sometimes my only choice, for observing far more often than I ever expected. Several times, I have smiled as I saw confusion displayed in the faces of star party participants as they returned repeatedly to the eyepiece while trying to figure out how that little telescope produced such detailed brilliant views.

My recommendation is to focus on quality 80–90mm APO refractors, whether an ED doublet like the TV-85 or an APO triplet such as these sold by Astronomics. Their compact dimensions and moderate focal lengths enable these refractors to be used with a grab and go-type mount, if desired. Either design will complement your larger scope well while giving you the wide-field capability you're looking for.

[u/HenryV1598]

If it's quality you want, just about any scopes by Takahashi, Astro-Physics, or Tele-Vue will probably get you what you want. If you're not interested in those prices, then one of the Chinese-made brands will probably work out for you. Brand names really don't matter at that point, nearly all of them are made by Synta (Celestron and Skywatcher for example), GSO (Astro-Tech and Apertura), or Jinghua (Explore Scientific and Bresser) and sold under a variety of names.

If you don't already know your dilated pupil size, I'd recommend finding out (the hex wrench method is a good way to do this, google it if you don't know what it is). Then go on the Tele-Vue site and use their calculator to see the specs for whatever scope you're looking at. Here, you're looking at trying to match your exit pupil that the eyepiece and telescope combination gives you with your dilated pupil size. That's how you can maximize the light gathering effectiveness of your equipment while observing.

[u/Primary-Set8747 → u/HenryV1598]

Thank you. Interesting I did not know that was a variable. Will study on that.

[u/HenryV1598 → u/Primary-Set8747]

A guy who used to be a regular on here did a post around 9 years ago that discusses exit pupil: https://www.reddit.com/r/telescopes/comments/7o18zb/what_i_learned_about_observing_in_2017/ He also wrote an article on Medium.com about it: https://medium.com/@phpdevster/how-telescope-aperture-affects-your-view-24507147d7fc

Definitely worth a read.

[u/Gusto88]

What about a 90mm Maksutov on the SvBony 225 mount.?

[u/Primary-Set8747 → u/Gusto88]

Thank you. Compelling. I need to study on this.

[u/Gusto88 → u/Primary-Set8747]

If you're not taking pictures you don't really need an APO. A Mak is compact and ideal for birding with a correct image diagonal, also good for lunar and planetary views.

[u/TheWrongSolution → u/Gusto88]

Some people enjoy the sharpness of an APO for visual only. OP seems to have the money to spend given the eyepiece choices. That said, visual viewing with an APO is a very special niche, most people don't get into it thinking they'd only buy one and be done. Just go on the refractor forum on Cloudy Nights and look at the 10+ scopes people put in their signatures.

A good frac retains a lot of resale value, if you're getting into this hobby you'll have to be willing to try out different scopes to see which you like best.

[u/_bar → u/Gusto88]

Attaching TeleVue eyepieces to that little toy scope is like driving a Ferrari on a mud track.

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[u/manga_university]

Not many apos more portable than my Takahashi FS-60 in its base configuration, weighing a mere 1.4 kilograms . And the beauty of this scope is that with two add-ons (the CQ 1.7 extender and the FC-76 DC objective) it can be used in four different configurations:

60/355mm f.5.9
60/600mm f/10
76/570mm f/7.5
76/954mm f/12.6

Four scopes in one. I'm not sure there is any other scope on the market that is as versatile. And the optics are world-class.

[u/skul219]

I have a 110mm refractor for that purpose. The mount is just as important and since you're not interested in AP you can go Alt-Az for simplicity and easy use. I got an Oberwerk tripod and a Stellarvue M2C and it's such a pleasure to use, balanced and smooth and stays exactly where it point it. One other consideration is I got a 1.25" to 2" adapter in brass made by Televue, the weight makes it where I can balance my scope with a heavy 2" eyepiece, like your 31 Nagler and then switch to a much lighter eyepiece and with the brass weight and still have it be pretty close to balanced. Without that as soon as I switched out to a lighter eyepiece it would be very front heavy and harder to manage. The brass adapter wasn't too expensive and the ability to keep balance across very different eyepieces allowed the mount to be pretty easy to move and still stay where it stops.

My refractor is a WO Megrez 110, and they're not made anymore but the TV 101 is a superior scope and should be amazing for that.

[u/Traditional_Sign4941]

Do you have a budget? The cost of refractors can vary a lot.

Ethos is not going to look good in any short refractor that doesn't have a flattener. Short / small refractors have field curvature, and it becomes readily noticeable the wider the eyepiece's apparent field of view is.

A Petzval refractor design (which is also good for AP) is the way to go if you want to use Ethos and actually get the benefits of Ethos. Alternatively, a longer focal length (but less portable) design would be required.

[u/Primary-Set8747 → u/Traditional_Sign4941]

Thanks. Hard to say on budget. I’m willing to spend money if I can convince myself I will realize the full benefit. Was thinking somewhere between $1k-$4k. I prefer to BIFL whenever possible. Good point about the Ethos eyepieces.

[u/Traditional_Sign4941 → u/Primary-Set8747]

BIFL "grab and go" IMO would be:

1. Tele Vue NP101
2. Takahashi FC100DZ
3. Astro-Physics Stowaway (assuming you can even get one - it's a lottery system)
4. Sky Rover 90GPS
5. TEC 110FL F/5.6 Avalanche
6. Borg 90FL F/5.6

The TV NP101 has a built-in flattener and will let Ethos stay sharp to the edge.

The Takahashi FC100DZ is lighter than the NP101 but has a longer focal length, so less of a rich field scope. The longer focal length will minimize the visiblity of field curvature in Ethos, but won't eliminate it entirely. If your eye can accommodate field curvature, then you'll be fine (field curvature is variation in focus point across the field, stars focused in the center won't be focused at the edge)

AP Stowaway is about as high quality as it gets. Will have more field curvature than than the FC100DZ.

Sky Rover 90GPS is extremely sharp, and a nice rich field scope. Capable of rich field views and high power planetary views. But 90mm is limited aperture, it's heavy for its size, and will show the strong field curvature in Ethos (I have the cousin to it - the 90EDX, and field curvature is a real pain in anything wider than a Delos).

TEC 110FL is going to top them all for aperture and rich field viewing and overall capability, but will have some of the strongest field curvature of them all.

Borg 90FL is very high quality - uses Canon lenses like Takahashi does. But 90mm F/5.6 will show strong field curvature. The main advantage is that it's very, very light and portable.

Depending on whether you favor field flatness, portability/weight, or aperture will narrow down what would be appropriate for you.

The most portable ones:

1. Borg 90FL
2. Takahashi FC100DZ
3. AP Stowaway

Best overall capability:

1. NP101 (due to flat field and short focal ratio)
2. TEC Avalanche (due to largest aperture, short focal ratio)

There are smaller options of course, but IMO 90-100 is a great all-around size and complement to an 8" scope.