46 replies to this topic

[Tony Flanders]

Just about a year ago I bought my first APO as a 70th birthday present to myself. I did it for a variety of reasons, including simply scratching an itch. I knew I'd always be dreaming of buying an APO if I didn't actually do so.

 

My choice was an AT80EDT on the grounds that I wanted the scope to be clearly superior to my very first -- the Tele Vue Ranger -- in every way except price and portability. Actually, in inflation-adjusted dollars, the AT80EDT is considerably cheaper than the Ranger was when I bought it 28 years ago -- which makes its far superior optical and mechanical quality all the more impressive. As a cute plus, the AT80EDT has exactly the same focal length as the Ranger (480 mm), meaning that with any given eyepiece it delivers the same magnification, but with a bit more aperture to back it up, and much less false color on bright objects.

 

On the other hand, the AT80EDT is nowhere close to the Ranger in terms of portability. It's small enough, but weighs more than twice as much, and requires a much beefier mount. Which may be a good thing, because I finally splurged for a Bogen 3046 tripod, which works far better than lighter tripods do for the Ranger. Eventually I think I will want a Go To mount for the AT80EDT -- or more likely two, a lightweight alt-az Go To for visual observing, and a serious EQ mount for imaging. But the Bogen 3046 is just about ideal for wide-field browsing, and still perfectly adequate at high power.

 

All this raises the question: what's an APO good for? Part of the answer is that APOs are ideal for attaching cameras and other instruments -- but I haven't gotten around to doing that yet. For the moment, I'm thinking strictly in terms of visual observing.

 

From one point of view, APOs are good for everything. From a more cynical point of view, they're good for nothing, due to their ridiculously small apertures. (I'm basically a Dob kinda guy.) With the hindsight of a year of (admittedly rather limited) experience, I'd say that they excel at two things: providing truly expansive low-power, wide-field views, and providing great views of bright stars and multiple-star systems -- within the limits of their apertures. Oh yes, and they're also great for viewing Venus. Not so great on the other planets, due to their tiny apertures, but since there's hardly any detail to see on Venus, small aperture isn't much of a limitation. Likewise for stars -- they show precisely zero detail in any telescope, no matter how big. But if you want to see diffraction rings, you can't do better than a small APO.

 

I spent a very enjoyable few hours a couple of nights ago on my first serious deep-sky session with the AT80EDT -- the kind where I actually record my observations, and look for objects other than the two or three hundred that I more or less know by heart. I tried all three of my two-inch eyepieces with the telescope, the 27-mm Panoptic, 30-mm UFF, and 40-mm Orion Optiluxe. I specially bought the 30-mm UFF as a companion for the scope, and indeed it proved to be the best of the lot for my purposes. The Optiluxe is a great finder eyepiece, but 12X is ridiculously low magnification for an 80-mm scope, especially given that my pupils now open only to 4.5 mm. The 27-mm Panoptic shows significantly fainter star and finer details than the 30-mm UFF, but at the cost of a much smaller true field of view. The difference in TFOV is much bigger than the numbers suggest, because I can see very nearly the entire field of the UFF in a glance, even while wearing glasses, whereas I have to crane my neck at weird angles to see the Panoptic's field stop.

 

I also viewed (or attempted) all the same targets with my Oberwerk 15x70 Deluxe binoculars. It was quite an instructive comparison, because those binos theoretically have almost exactly the same true field of view as the scope with the 30-mm eyepiece, slightly over 4 degrees. But again, I absolutely cannot see the whole field of view of the binoculars wearing glasses, and my astigmatism is really obtrusive at wide-open exit pupils when I don't wear my glasses. Also, it's much easier to fit the scope with filters, which mattered for some of my targets, notably the Rosette Nebula.

 

As is my custom, I was using the binoculars hand-held, so it's not surprising that I could see much finer detail with the scope. On the flip side, large, none-too-bright objects like M46 definitely had more presence in the binoculars. That's not surprising given that the binoculars two 70-mm objectives gather far more light than the scope's 80-mm objectives. And as we all know, two eyes really are better than one.

 

Overall, though, I'd have to say that I enjoyed wide-field observing a lot more in the scope than in the binoculars, due primarily to the 90-degree viewing angle. Oh, by the way, I was using an Amici prism. I have no desire to return to a conventional star diagonal, except maybe for splitting close double stars. I despise mirror-imaged views, especially at low power where the correlation between the naked-eye view and the view through the scope is so obvious.

 

For close-up views I used my Baader Hyperion 8-24 zoom, which I find complements the scope beautifully. I was observing the tail end of the winter Milky Way, in Monoceros, Canis Major, Puppis, and Hydra, which contains many bright clusters and nebulae that are well suited to small apertures. Even so, I kept thinking "gosh, I sure wish I had just a little more aperture." Any way you slice it, 80 mm isn't much. Nor is 100 mm, for that matter.

 

I ended the session just before the Moon rose by observing NGC 2903, the first of the great spring galaxies. It was nice enough, and perhaps even exhibited a hint of its bar structure. But I think I will put away the little refractor for galaxy season, and return to my 7-inch and 12.5-inch Dobs. Which, when all is said and done, are much more versatile instruments as far as visual observing is concerned. And certainly far superior for galaxies.

Edited by Tony Flanders, 20 March 2025 - 08:18 PM.

[Jon Isaacs]

Tony:

 

I have several ED/APO refractors..  I am basically a Dob/fast refractor guy.  Under dark skies I typically setup a fast refractor and a Dob.. They provide balance.  From my urban backyard, I enjoy the convenience of the refractor...  I enjoy splitting doubles.. Some nights I will out there with the 10 inch or 13.1 inch going for sub-arc-second doubles.  Some nights I just enjoy looking at what might pass for easier doubles.  

 

Tonight, I am kind of tired after getting up at 3:45 am to take my sister to the hospital for some surgery..  I am thinking 4 inch ED/apo... Plus the Meade 277, a 60mm F/5 achromat... 

 

Jon

[SoCalPaul]

Good write-up, Tony. I am impressed that you know two or three hundred DSOs by heart.

 

I appreciate the sharp, high contrast views I get in an APO, but as the saying goes, "aperture wins".

 

There is a degree of self-satisfaction in finding difficult objects in an APO, leveraging the high contrast to meet the challenge.

 

But if you want to see more detail, it's no contest- bigger is better. (Assuming the bigger glass is decent quality.)

 

Otherwise, wide-field can be better in a smaller APO, as you say above.

 

Clear skies,

Paul

[sevenofnine]

Very nice astro report! I feel about the same way with my AT80ED. What it can see is splendid but it runs out of light too fast for some objects. I either choose targets that I know will look good or just sweep looking for something interesting. I do find that I see more using a tracking mount. This Sky-Watcher AZ-GTi is not perfect but the tracking works well enough and go-to is handy 

 

.

Edited by sevenofnine, 20 March 2025 - 09:45 PM.

[weis14]

Nice writeup Tony.  I think you have really hit on the issues with small refractors and why some people love them to the point that they are almost the only scope I use (me) and why others think they are interesting for wide fields, but quickly turn to larger scopes.

 

Larger scopes allow for more detail and fainter objects to be seen, but smaller ones actually get used.  I made it out in a bone-chilling windchill tonight for a 45 minute session with my Stowaway.  I guarantee that any scope larger than that would have caused me to stay inside instead.  If you are in a position where you can observe a lot, then the larger scope makes sense and the associated hassles with setting it up, waiting for cooldown, etc. are worth it.  However, if you barely have time to find 40 observing nights annually, with most sessions shorter than 3 hours, then larger scopes rapidly become a nuisance.  I know this first hand.  My C9.25 was only used twice all of last year, and one of those sessions was for outreach.  I sold it earlier this year when I realized that using it was more of a hassle and I kept looking for reasons not to take it out.  I never have that problem with my small refractors.

[Jethro7]

Hello Toney,

Nice thoughtful write up. Thank you for sharing.

 

HAPPY SKIES AND KEEP LOOKING UP Jethro

[bobzeq25]

This is all true for visual observing, which is why visual observers generally prefer larger aperture scopes.

For imagers, the advantages of APOs generally dominate. Long total imaging times can, to a large degree, substitute for aperture. Some imagers also use large aperture scopes, but do so significantly less frequently than visual observers.

Example (click on it for a better version, and details). A visual observer would not likely want to use a small APO (this is a 70mm) for observing this target, but the small APO does just fine when used as an imager.

[Astro-Master]

Tony, nice write up.

 

  I bought my first refractor about 8 years ago, a Stellarvue 105mm Triplet after seeing double stars in my friend's Stellarvue 102 ED Doublet.  I love the perfect Double Star images in my APO at high power using a TV 3-6 Zoom 122x to 245x and with a 2x Barlow on the tight doubles.

 

Well, your all set for sweeping the Summer Milky Way with your new scope.  

 

Clear Skies

Bruce

[Achernar]

I have one of these telescopes myself. Before I started using it as an astrograph, I did some visual observing with it. I was very impressed with the sharpness and extremely good color correction. It can show very dim objects such as the California nebula with a hydrogen beta filter. No, it's no match for a 15-inch Dob, let alone a 6-inch Dob, but a small apochromatic refractor can do very well for low-power, wide-field visual observing.

 

Taras

 

 

 

 

Edited by Achernar, 21 March 2025 - 12:13 AM.

[Tony Flanders]

Larger scopes allow for more detail and fainter objects to be seen, but smaller ones actually get used.  I made it out in a bone-chilling windchill tonight for a 45 minute session with my Stowaway.  I guarantee that any scope larger than that would have caused me to stay inside instead.

Unfortunately for my 80-mm APO, it lives in the same room as my 7-inch Dob, which is considerably easier and faster to set up, as well as being easier and more comfortable to use. The Dob does have a much longer cool-down time, which would be a major issue at my city home. But not at my country home, where I can leave the Dob outside to cool down as long as I have the foresight to know that I'll want it soon. So all the time I'm using the APO, the thought that I could be using the Dob instead is whispering over my shoulder.

 

I do think that the little refractor would benefit greatly from a tracking mount for high-power observing. And Go To would eliminate the problem of finding objects high in the sky. But a tracking mount would be irrelevant or counterproductive in the refractor's role as a low-power sky-sweeper.

 

I certainly agree with bobzeq25 that APOs really come into their own when used for imaging. I just haven't gotten around to doing that yet.

[Jon Isaacs]

Unfortunately for my 80-mm APO, it lives in the same room as my 7-inch Dob, which is considerably easier and faster to set up, as well as being easier and more comfortable to use. The Dob does have a much longer cool-down time, which would be a major issue at my city home. But not at my country home, where I can leave the Dob outside to cool down as long as I have the foresight to know that I'll want it soon. So all the time I'm using the APO, the thought that I could be using the Dob instead is whispering over my shoulder.

 

I do think that the little refractor would benefit greatly from a tracking mount for high-power observing. And Go To would eliminate the problem of finding objects high in the sky. But a tracking mount would be irrelevant or counterproductive in the refractor's role as a low-power sky-sweeper.

 

I certainly agree with bobzeq25 that APOs really come into their own when used for imaging. I just haven't gotten around to doing that yet.

 

Tony:

 

I find that alt-az mounts with slow motion controls like the Portamount 2, the SkyTee, the original Astro-Tech Voyager are easy to use at higher magnifications. They can be slewed at low to mid powers but for centering and tracking at high magnifications, I just dial them in.  

 

Last night, I setup my 13.1 inch F/5.5 Dob and the little AT-70ED.  The AT-70ED is super easy to setup.  The tripod has eyepiece racks and the entire rig is light enough even when loaded with eyepieces that I can carry it outside with one hand.  I probably spent an equal amount of time with each scope.  The thought I could be using a Dob, it's right there if that's what catches my fancy. 

 

For observing with just a refractor, I find a 4 inch is more satisfying.  It's significantly larger than an 80mm but it is still relatively easy to carry outside all setup with eyepieces in the tray, all ready to go.  

 

The other night from San Diego:

 

 

Three scopes is unusual for me, two sometimes from my urban backyard, nearly always from dark skies.  They complement each other.. 

 

Jon

 

P.S.  Recently I learned from Tony the difference between compliment and complement.  My scopes do compliment each other.  Sometimes during the day I hear them whispering to one another.. "I love your big, beefy truss poles" and "that objective lens sparkles in the star light." 

Edited by Jon Isaacs, 21 March 2025 - 05:43 AM.

[John R.]

Thanks for the write up. While an APO is not in my future, perfectly happy my 80ED, (especially price/performance) it is still nice to hear others honest opinion. 

 

A 7 inch dob? Seems like an odd size. Would be interesting to hear about it.  

[City Kid]

So all the time I'm using the APO, the thought that I could be using the Dob instead is whispering over my shoulder.

This is my experience. I've never gone out with one of my Dobs and wished I had my refractor instead. But I've definitely gone out with a refractor and wished I had one of my Dobs. That's why I repurposed my 80mm to a spotting scope and I got a Lunt solar filter for my 101mm. However one of my all time favorite object/scope combinations is M31 in my NP101 with 13mm Ethos. But that's only the case out in Nebraska at NSP. In my normal skies all DSO's are lacking in my refractors.

[Jon Isaacs]

This is my experience. I've never gone out with one of my Dobs and wished I had my refractor instead. But I've definitely gone out with a refractor and wished I had one of my Dobs. That's why I repurposed my 80mm to a spotting scope and I got a Lunt solar filter for my 101mm. However one of my all time favorite object/scope combinations is M31 in my NP101 with 13mm Ethos. But that's only the case out in Nebraska at NSP. In my normal skies all DSO's are lacking in my refractors.

 

At the end of the evening when it's time to put everything away.. that is when you might have ywished you'd brought out a refractor.

 

Jon

[kmparsons]

You can see plenty with a small apo! A 70mm aperture gathers 100 times the light of your fully-dilated pupil. I had my teeny-tiny 60mm out last night and had a most enjoyable session. From a dark sky site a small apo can open the universe for you. 

[balcon3]

 

For close-up views I used my Baader Hyperion 8-24 zoom, which I find complements the scope beautifully. I was observing the tail end of the winter Milky Way, in Monoceros, Canis Major, Puppis, and Hydra, which contains many bright clusters and nebulae that are well suited to small apertures. Even so, I kept thinking "gosh, I sure wish I had just a little more aperture." Any way you slice it, 80 mm isn't much. Nor is 100 mm, for that matter.

 

I enjoyed reading your post. I just want to comment on this one section. In my experience, as Jon says above, there is a significant difference between an 80mm Apo and a 100mm Apo. With my AT80EDL, I do often wish that I had more aperture. But with my Takahashi FC100DF I rarely feel that way. A good 100mm Apo can give really nice views of planets. Not, of course, better than a 12.5 inch Dob, but still a lot of detail. Indeed, since getting my 100mm Apo, I find myself using my Mewlon 180c less. The Mewlon shows much more detail on Jupiter, Saturn and the moon, and resolves globular clusters significantly better. But still, the 100mm Apo always puts up engaging views. So I guess my message is that before you relegate smaller Apos to widefield and double star duty, try a 100mm. They show much more than an 80mm and are still easy to set up and mount. 

[BKBrown]

Well said Tony, as always. Let me start by saying that I love my APOs and ED doublets regardless of their aperture. The clarity and crispness of the views they provide never disappoint, and much larger aperture is immediately available. Being in a position to build an observatory under dark rural skies has been a blessing, and I suspect that without it my big SCTs might not find much future employment (especially the EdgeHD 14 ). But if I had to reduce my holdings, I would retain my best three or four refractors and a couple of decent mounts with tracking options. With todays excellent eye pieces, cameras, and EAA/NVA options I will never run out of things to see or the ability to go deep. And a 140mm APO  is plenty of gun to take hunting.

 

Like Jon and many others here, I like to use different scopes simultaneously. I just keep them on the same mount, and aligned to point at the same target.

 

 

Clear Skies,

Brian 

[Jon Isaacs]

 

For close-up views I used my Baader Hyperion 8-24 zoom, which I find complements the scope beautifully. I was observing the tail end of the winter Milky Way, in Monoceros, Canis Major, Puppis, and Hydra, which contains many bright clusters and nebulae that are well suited to small apertures. Even so, I kept thinking "gosh, I sure wish I had just a little more aperture." Any way you slice it, 80 mm isn't much. Nor is 100 mm, for that matter.

 

For close up, I want more magnification than 60x.. Small refractors excel at cleanly splitting close doubles but it doesn't happen at 60x.  Even for DSOs, globulars, planetary nebulae, I am going 150x with an 80mm, sometimes more.  

 

I find my small refractors great fun....  Not as capable as a 16 inch or 22 inch Dob but they challenge me is different ways.

 

Jon

[Tony Flanders]

For close up, I want more magnification than 60x.. Small refractors excel at cleanly splitting close doubles but it doesn't happen at 60x.  Even for DSOs, globulars, planetary nebulae, I am going 150x with an 80mm, sometimes more.

That's an excellent point. Some of the open clusters I observed would obviously have profited from magnifications above 60X. And I bet that would also be true for Hubble's Variable Nebula, NGC 2261. If I get another chance during this Moon cycle -- which is beginning to look a little doubtful -- I will make another pass over the entire list using a bit more magnification.

[Wildetelescope]

Just about a year ago I bought my first APO as a 70th birthday present to myself. I did it for a variety of reasons, including simply scratching an itch. I knew I'd always be dreaming of buying an APO if I didn't actually do so.

 

My choice was an AT80EDT on the grounds that I wanted the scope to be clearly superior to my very first -- the Tele Vue Ranger -- in every way except price and portability. Actually, in inflation-adjusted dollars, the AT80EDT is considerably cheaper than the Ranger was when I bought it 28 years ago -- which makes its far superior optical and mechanical quality all the more impressive. As a cute plus, the AT80EDT has exactly the same focal length as the Ranger (480 mm), meaning that with any given eyepiece it delivers the same magnification, but with a bit more aperture to back it up, and much less false color on bright objects.

 

On the other hand, the AT80EDT is nowhere close to the Ranger in terms of portability. It's small enough, but weighs more than twice as much, and requires a much beefier mount. Which may be a good thing, because I finally splurged for a Bogen 3046 tripod, which works far better than lighter tripods do for the Ranger. Eventually I think I will want a Go To mount for the AT80EDT -- or more likely two, a lightweight alt-az Go To for visual observing, and a serious EQ mount for imaging. But the Bogen 3046 is just about ideal for wide-field browsing, and still perfectly adequate at high power.

 

All this raises the question: what's an APO good for? Part of the answer is that APOs are ideal for attaching cameras and other instruments -- but I haven't gotten around to doing that yet. For the moment, I'm thinking strictly in terms of visual observing.

 

From one point of view, APOs are good for everything. From a more cynical point of view, they're good for nothing, due to their ridiculously small apertures. (I'm basically a Dob kinda guy.) With the hindsight of a year of (admittedly rather limited) experience, I'd say that they excel at two things: providing truly expansive low-power, wide-field views, and providing great views of bright stars and multiple-star systems -- within the limits of their apertures. Oh yes, and they're also great for viewing Venus. Not so great on the other planets, due to their tiny apertures, but since there's hardly any detail to see on Venus, small aperture isn't much of a limitation. Likewise for stars -- they show precisely zero detail in any telescope, no matter how big. But if you want to see diffraction rings, you can't do better than a small APO.

 

I spent a very enjoyable few hours a couple of nights ago on my first serious deep-sky session with the AT80EDT -- the kind where I actually record my observations, and look for objects other than the two or three hundred that I more or less know by heart. I tried all three of my two-inch eyepieces with the telescope, the 27-mm Panoptic, 30-mm UFF, and 40-mm Orion Optiluxe. I specially bought the 30-mm UFF as a companion for the scope, and indeed it proved to be the best of the lot for my purposes. The Optiluxe is a great finder eyepiece, but 12X is ridiculously low magnification for an 80-mm scope, especially given that my pupils now open only to 4.5 mm. The 27-mm Panoptic shows significantly fainter star and finer details than the 30-mm UFF, but at the cost of a much smaller true field of view. The difference in TFOV is much bigger than the numbers suggest, because I can see very nearly the entire field of the UFF in a glance, even while wearing glasses, whereas I have to crane my neck at weird angles to see the Panoptic's field stop.

 

I also viewed (or attempted) all the same targets with my Oberwerk 15x70 Deluxe binoculars. It was quite an instructive comparison, because those binos theoretically have almost exactly the same true field of view as the scope with the 30-mm eyepiece, slightly over 4 degrees. But again, I absolutely cannot see the whole field of view of the binoculars wearing glasses, and my astigmatism is really obtrusive at wide-open exit pupils when I don't wear my glasses. Also, it's much easier to fit the scope with filters, which mattered for some of my targets, notably the Rosette Nebula.

 

As is my custom, I was using the binoculars hand-held, so it's not surprising that I could see much finer detail with the scope. On the flip side, large, none-too-bright objects like M46 definitely had more presence in the binoculars. That's not surprising given that the binoculars two 70-mm objectives gather far more light than the scope's 80-mm objectives. And as we all know, two eyes really are better than one.

 

Overall, though, I'd have to say that I enjoyed wide-field observing a lot more in the scope than in the binoculars, due primarily to the 90-degree viewing angle. Oh, by the way, I was using an Amici prism. I have no desire to return to a conventional star diagonal, except maybe for splitting close double stars. I despise mirror-imaged views, especially at low power where the correlation between the naked-eye view and the view through the scope is so obvious.

 

For close-up views I used my Baader Hyperion 8-24 zoom, which I find complements the scope beautifully. I was observing the tail end of the winter Milky Way, in Monoceros, Canis Major, Puppis, and Hydra, which contains many bright clusters and nebulae that are well suited to small apertures. Even so, I kept thinking "gosh, I sure wish I had just a little more aperture." Any way you slice it, 80 mm isn't much. Nor is 100 mm, for that matter.

 

I ended the session just before the Moon rose by observing NGC 2903, the first of the great spring galaxies. It was nice enough, and perhaps even exhibited a hint of its bar structure. But I think I will put away the little refractor for galaxy season, and return to my 7-inch and 12.5-inch Dobs. Which, when all is said and done, are much more versatile instruments as far as visual observing is concerned. And certainly far superior for galaxies.

I think that this is an excellent post!   I personally lean toward refractors, and I agree with everything you say here in your description of your experience with the smaller refractors.  A good, well colliimated dob will pull in more detail and fainter objects every time.   For a refractor to compete, it has to get large enough that the dob is the more portable option.  I have the 80 mm EDT and it is likely the perfect upgrade to your pronto, and a good complement to your dobs!  What I really like about your post is that you provide context regarding what and how YOU like to observe, and IMHO fairly assess how the small refractor fits into that routine.  I really enjoyed reading it!  I also share your love of naked eye observing;-). 

 

Cheers!

 

JMD

 

Edit!  Just read Jon’s post and have to change compliment to complement!  Although in my experience the 80 EDT is quite well mannered so I think Either would apply:-)

[azure1961p]

Only the fondest memories of my TV Ranger.  Some blue to be sure, but tye sharpness on planets and moon was exquisite.

 

Glad you like your new scope Tony.

 

Pete

[Jon Isaacs]

That's an excellent point. Some of the open clusters I observed would obviously have profited from magnifications above 60X. And I bet that would also be true for Hubble's Variable Nebula, NGC 2261. If I get another chance during this Moon cycle -- which is beginning to look a little doubtful -- I will make another pass over the entire list using a bit more magnification.

 

Tony:

 

My strategy is to have a sufficient number of eyepieces with me that I can achieve any imaginable possible magnification. With a scope like your AT-80EDT that would include something around 3.5 mm plus a 2x Barlow.

 

For this purpose (on my relatively dry climate), the Bogen 3046 tripod is just about perfect. The widely splayed upper legs are perfect for mounting eyepiece racks. The eyepieces are at my fingertips and add little weight, it's still easy grab and go.

 

 

For anyone concerned about eyepiece safety, they're self locking:

 

 

I started using the racks nearly 25 years ago. I was only about 3 years ago that I realized I could use the same tripod with an accessory tray on top with all my scopes. It's amazing, it's like a portable observing table so I have everything right at my fingertips, I don't even have to standup to swap eyepieces or get a filter. It works great in rocky terrain, sandy or muddy soil.

 

 

----------------

 

That said. Tony.. I've known you a long time. You are a very skilled observer who is an observer through and through and not a gear head. You are very practical, what impresses you is what you see, not what you see it with..

 

Furthermore, you started with a 70 mm Ranger and spent time learning to observe with it. I believe observing with a smaller scope helps us become better observers, you learn to get the most out of the light and resolution you have.

 

I consider my myself an observer in a similar way to Tony but I'm also a bargain hunter and have more space.. I started with small scopes but they weren't very good, my first decent scope was a late 1970s Orange tube C-8. By the time I had a decent refractor, a TeleVue Pronto, I had a 12.5 inch Dob.

 

So for me, I'm kind of a big scope but who enjoys small refractors for the balance they provide. And I do like pristine views, whether it's the 12 mm Ethos with a Paracorr 2 in the  22 inch or the 31 mm Nagler in the NP-101..

 

Tony's more practical.. he has had an Orion 100 mm F/6 achromat for quite a number of years. For many aspects of deep sky observing, it shows just about everything the NP-101 does.

 

So Tony's take on the AT-80EDT is particularly interesting because it's unencumbered by the dazzle and bells and whistles of a small APO...

 

So.. I'm curious how Tony compares the AT-80EDT to the 100 mm F/6 achromat??!

 

Jon

[Oldfracguy]

 

Overall, though, I'd have to say that I enjoyed wide-field observing a lot more in the scope than in the binoculars, due primarily to the 90-degree viewing angle. Oh, by the way, I was using an Amici prism. I have no desire to return to a conventional star diagonal, except maybe for splitting close double stars. I despise mirror-imaged views, especially at low power where the correlation between the naked-eye view and the view through the scope is so obvious.

 

 

Outstanding, Tony, and a most candid assessment.

 

What make and model Correct Image Amici Prism diagonal are you using in your AT80EDT?

[Tony Flanders]

 

Tony:

 

My strategy is to have a sufficient number of eyepieces with me that I can achieve any imaginable possible magnification. With a scope like your AT-80EDT that would include something around 3.5 mm plus a 2x Barlow.

 

For this purpose (on my relatively dry climate), the Bogen 3046 tripod is just about perfect. The widely splayed upper legs are perfect for mounting eyepiece racks. The eyepieces are at my fingertips and add little weight, it's still easy grab and go.

 

 

 

For anyone concerned about eyepiece safety, they're self locking:

 

 

 

I started using the racks nearly 25 years ago. I was only about 3 years ago that I realized I could use the same tripod with an accessory tray on top with all my scopes. It's amazing, it's like a portable observing table so I have everything right at my fingertips, I don't even have to standup to swap eyepieces or get a filter. It works great in rocky terrain, sandy or muddy soil.

 

 

 

----------------

 

That said. Tony.. I've known you a long time. You are a very skilled observer who is an observer through and through and not a gear head. You are very practical, what impresses you is what you see, not what you see it with..

 

Furthermore, you started with a 70 mm Ranger and spent time learning to observe with it. I believe observing with a smaller scope helps us become better observers, you learn to get the most out of the light and resolution you have.

 

I consider my myself an observer in a similar way to Tony but I'm also a bargain hunter and have more space.. I started with small scopes but they weren't very good, my first decent scope was a late 1970s Orange tube C-8. By the time I had a decent refractor, a TeleVue Pronto, I had a 12.5 inch Dob.

 

So for me, I'm kind of a big scope but who enjoys small refractors for the balance they provide. And I do like pristine views, whether it's the 12 mm Ethos with a Paracorr 2 in the  22 inch or the 31 mm Nagler in the NP-101..

 

Tony's more practical.. he has had an Orion 100 mm F/6 achromat for quite a number of years. For many aspects of deep sky observing, it shows just about everything the NP-101 does.

 

So Tony's take on the AT-80EDT is particularly interesting because it's unencumbered by the dazzle and bells and whistles of a small APO...

 

So.. I'm curious how Tony compares the AT-80EDT to the 100 mm F/6 achromat??!

 

Jon

 

Yeah, I'm curious too. We will just have to wait a while, because I'm sick of wasting my precious few clear moonless hours comparing different telescopes. I want to spend more time looking at the sky now.

 

Truth be told, it's been a long, long time since I last used the 100-mm f/6 achromat. There's just not much that it does that another of my scopes doesn't do better, and with less fuss. Also, I'm reasonably sure it doesn't have enough in-focus to handle a 2-inch Amici prism.

[Tony Flanders]

For close up, I want more magnification than 60x.. Small refractors excel at cleanly splitting close doubles but it doesn't happen at 60x.  Even for DSOs, globulars, planetary nebulae, I am going 150x with an 80mm, sometimes more.

Well, I did in fact get one last clear moonless night before the late winter Milky Way becomes unobservable. This time instead of using my 8-24 zoom for closeups, I used my Pentax XL's: 14, 10.5, 7, and 5.2 mm for 34X, 46X, 69X, and 92X, respectively. I didn't want to bother with a Barlow, and my 4-mm eyepiece is at my other home. In any case I don't think it would have helped much with any of my targets.

And indeed, 60X is lower than optimal for most of those DSOs in an 80-mm APO. For instance, I got significantly better resolution of M46 and M93 at 92X than at 69X -- though M46 barely fit in the field of view at the higher magnification. NGC 2261, Hubble's Variable Nebula, was a more interesting case. I had seen barely any detail at 60X with the 8-24 zoom, but the 7-mm Pentax at 69X showed the comet-like structure clearly while still leaving the nebulosity quite bright. The nebulosity became surprisingly dim at 92X, but arguably showed more structure, especially when using averted vision.

 

I was using my 7-inch Dob side by side. It happens to have exactly the twice the AT80EDT's 480-mm focal length, allowing me to use identical magnifications in both scopes. I confirmed that for the brightest and coarsest of the clusters that I observed, such as M41 or M47, magnification makes much more difference than aperture. But when it came to M46, the bigger scope allowed me to see more stars at lower magnification, yielding a far more pleasing view. Moreover, NGC 2438, the superposed planetary nebula, was just sitting there in plain view through the 7-inch, whereas I couldn't make it out at all in the 80-mm scope. (Granted, I didn't really try all that hard.)

 

The difference in aperture is most obvious by far on nebulosity rather than star clusters. Hubble's Variable Nebula is gloriously bright in a 7-inch scope, and the aperture allows me to use all the magnification this object deserves without fading below visibility. Nonetheless, it has an ethereal beauty of its own in the smaller scope.