849 replies to this topic

[Rich V.]

It's also clear to me that small refractors aren't so susceptible to poor seeing.  I view in an area with high, steep mountains just west of my location.  It's very difficult to count on good planetary seeing, particularly with larger aperture scopes. 

 

I have much greater success with my 80mm or 130mm refractors.  The little 80mm will frequently show Jupiter's moon transits and the GRS in just so-so seeing.  It's also a great companion to binos on those nights where the Moon intrudes into the darkness and becomes the dominant target as well.

[Fiske]

Out with the big scope tonight, as it will be the last clear night for some time to come. Paired it with the rubberized 8x42, because I am observing mostly standing tonight and don’t want to bump instruments into each other and inflict damage. This is more a case of a support binocular than support scope though, to see what Jupiter brings tonight 

 

Switched on my outdoor lights to facilitate in setting the 16” up, all switched off now.

 

IMG_8053.jpeg

If I were doing it now, I would build a 16-inch Dob instead of a 22-inch. 

 

That's a nice Dob, Erik. 

[Fiske]

It's also clear to me that small refractors aren't so susceptible to poor seeing.  I view in an area with high, steep mountains just west of my location.  It's very difficult to count on good planetary seeing, particularly with larger aperture scopes. 

 

I have much greater success with my 80mm or 130mm refractors.  The little 80mm will frequently show Jupiter's moon transits and the GRS in just so-so seeing.  It's also a great companion to binos on those nights where the Moon intrudes into the darkness and becomes the dominant target as well.

The forecast is for mostly clear skies tonight, with temps of around 32 degrees and 9 mph winds, which isn't wonderful, BUT I am eager to try out the AT-80 with the new Baader Amici diagonal, so we will see what happens.

 

[RMay]

That's a nice Dob, Erik.

Agree completely, Fiske… Erik, that’s a beauty.

Ron

[Cali]

 

I have much greater success with my 80mm or 130mm refractors.  The little 80mm will frequently show Jupiter's moon transits and the GRS in just so-so seeing.  It's also a great companion to binos on those nights where the Moon intrudes into the darkness and becomes the dominant target as well.

Rich V - Which little 80mm?

 

Thx

-Cal

[Rich V.]

The forecast is for mostly clear skies tonight, with temps of around 32 degrees and 9 mph winds, which isn't wonderful, BUT I am eager to try out the AT-80 with the new Baader Amici diagonal, so we will see what happens.

 

Beats the Pacific snow storm that's hitting the Tahoe area right now, Fiske!  The air is full of white stuff.

[norvegicus]

It has snowed here every day for the last week, and will for the next week....  it's probably time to switch hobbies and go skiing...

[Fiske]

It has snowed here every day for the last week, and will for the next week....  it's probably time to switch hobbies and go skiing...

Or just go skiing. The stars will still be there later. 

[norvegicus]

Or just go skiing. The stars will still be there later. 

Yep.  By switch hobbies I meant "for the next week or two".

[Fiske]

Yep.  By switch hobbies I meant "for the next week or two".

Well that's okay then. 

[jrazz]

Or just go skiing. The stars will still be there later. 

That's what I've been doing....

[Fiske]

So I had the AT-80 out last night with the 2-inch Baader Amici diagonal and to be candid, I am underwhelmed. 

 

Firstly, though, the Baader diagonal makes navigation a breeze. It essentially turns the telescope into a Right-Angle Correct-Image (RACI) finder. Even without a red-dot finder on it, I had no trouble navigating or getting objects in the view.

 

But it's an achromat, and no more aperture than the 82XL-SD, which is apochromatic with the added advantage of binocular summation. The AT-80 is a quality instrument, but being an achromat purple halos are present around brighter stars. I used a range of eyepieces including a 27mm Panoptic, 24mm Orion UFF (easily my favorite wide field eyepiece for the AT-80), 10/7/5mm Pentax XWs, a 4mm Televue Delite, and a 9mm Baader Morpheus. The most pleasing views were at lower magnifications, though, honestly, those suffer in comparison with lower magnification views with the 82XL-SD or Kowa Highlander. In fact, there is no comparison. Binocular vision makes that much difference. I had a look at M 35 with it, and it took me a while to realize, yeah, that is M 35, nothing nearly so engaging as viewing the cluster with a BT. But then that isn't really the point of the support telescope anyway.

 

To me, the role of the support telescope is to provide an easy, high magnification alternative to binoculars and binocular telescopes, mostly for closer double stars. I tried the AT-80 on STF 628, a double near the wonderful binocular double star STF 627, described in this observing report, but was unable to resolve it even at higher magnifications, presumably because 80mm is not sufficient aperture to make the 9.85 magnitude secondary visible near the brighter primary. Really, the limiting factor for magnification from my yard is atmosphere, not the optical quality of refractor diagonals compared with more complex binocular telescope prisms assemblies. The optical differences is not that significant. Certainly not at the typical magnifications current local viewing conditions support. I was able to fully resolve Castor in Gemini at 120x with the AT-80 (TV 4mm DeLite). The star images were not distorted, but were certainly not pinpoint sharp at 120x either.  I'm planning to do some comparisons between the AT-80 on doubles like Castor with the 100XL-SD at 80x or 112x (Pentax 7 and 5mm XW eyepieces).

 

Other comparisons will be made as well, and over multiple observing sessions.

 

A premium 80mm APO refractor would offer better performance, but it's still only 80mm (or 76mm for a Takahashi), and considering that I already own TV-101 and EON 120 APO refractors, which will easily outperform an 80mm APO in higher magnification views, there doesn't seem much point in going that route.

 

Part of the appeal of the 80mm refractor is that it's so easy to deploy. The TV-101 is a lot bulkier, but with the Amici diagonal the Mini-Borg finder would not be necessary and that would simplify setup. It still would not be grab and go like an 80mm though.

 

What this is really pointing to is the supremacy of the Celestron 6SE as a support telescope. 

Edited by Fiske, 11 January 2024 - 09:06 AM.

[jrazz]

I have come to the same conclusion e.i. I am spoiled by the APOs I own. Achromats are fine but they completely pale in comparison to the sharpness of these better corrected instruments.

 

That being said for less than $900....

https://www.kyoei-os...shi-foa-60.html

[Bill Barlow]

I was out yesterday evening as well Fiske with the C6.  Even with good collimation, the views were underwhelming.  To me it looked like there was atmospheric turbulence given an upper level disturbance moving through the region.  I couldn’t get sharply focused stars to save my life, which probably isn’t worth saving anyway.

 

Last night a mounted pair of 20x80 binoculars would have been a better option (if I owned them).

 

Bill

Edited by Bill Barlow, 11 January 2024 - 11:04 AM.

[Rich V.]

Rich V - Which little 80mm?

 

Thx

-Cal

Hi, Cal, it's a Russian LOMO 80/480 triplet in a SV tube w/FT focuser.

Attached Thumbnails

• 

[Erik Bakker]

That 80mm LOMO looks like a great binocular support scope to me.

[Scott99]

I have come to the same conclusion e.i. I am spoiled by the APOs I own. Achromats are fine but they completely pale in comparison to the sharpness of these better corrected instruments.

 

That being said for less than $900....

https://www.kyoei-os...shi-foa-60.html

The problem with apos is once you get one, it's hard to go back.  I find the same thing is happening to me in binoculars.  Once you spend time with a fully corrected bino, suddenly that color halo around Sirius or looking at ducks in the sun becomes most unwelcome

Edited by Scott99, 11 January 2024 - 11:48 AM.

[jrazz]

I'm going to go out on a limb and say that a cat that small isn't really going to give you any big advantages over a BT. Maybe as a companion to a 10x binocular but even a 82SD should easily match or exceed it on resolution - even if not on magnification.

 

That's why I think the best support telescope would be a smaller refractor. You won't get as much magnification but the resolution and sharpness would match.

 

Honestly it's tough. I would match the support telescope's aperture to the binocular's. Using a 70mm or 82mm BT? Use a 80mm apo. 100mm BT? 100mm apo (or in my case a 130mm apo ) 

[Rich V.]

That 80mm LOMO looks like a great binocular support scope to me.

IMO, it's the best possible "short tube" 80mm ever made.  LOMO knocked those LZOS OK4 triplets out of the park, so to speak.  Just excellent glass by any standard; gives all an 80mm aperture can offer.  Not light like an ST80 though, the lens cell is built like a Russian tank just like the SV tube/ hardware is.  It was a retirement present from my employer when I retired in 2007.  Beats the heck out of a watch.  

[Fiske]

I'm going to go out on a limb and say that a cat that small isn't really going to give you any big advantages over a BT. Maybe as a companion to a 10x binocular but even a 82SD should easily match or exceed it on resolution - even if not on magnification.

 

That's why I think the best support telescope would be a smaller refractor. You won't get as much magnification but the resolution and sharpness would match.

 

Honestly it's tough. I would match the support telescope's aperture to the binocular's. Using a 70mm or 82mm BT? Use a 80mm apo. 100mm BT? 100mm apo (or in my case a 130mm apo ) 

Well, Bill B seems pleased with his 6-inch SCT. And Erik with his 5-inch SCT. 

 

And I'm not going out on a limb. I'm actually going to compare them side by side. 

[Fiske]

I was out yesterday evening as well Fiske with the C6.  Even with good collimation, the views were underwhelming.  To me it looked like there was atmospheric turbulence given an upper level disturbance moving through the region.  I couldn’t get sharply focused stars to save my life, which probably isn’t worth saving anyway.

 

Last night a mounted pair of 20x80 binoculars would have been a better option (if I owned them).

 

Bill

Okay. So not really a fair 80mm refractor test.

 

I know where this is going to go. The AT-80 performance will be respectable on a better night, and I'll be tempted by an 80-90mm APO, break my vow to avoid acquisitions in 2024, and have to do some unspecified penance...

 

  

[norvegicus]

I have come to the same conclusion e.i. I am spoiled by the APOs I own. Achromats are fine but they completely pale in comparison to the sharpness of these better corrected instruments.

 

That being said for less than $900....

https://www.kyoei-os...shi-foa-60.html

That's a bargain for an FOA-60, which is the nicest 60 you can get anywhere, but it's still a 60.

 

Okay. So not really a fair 80mm refractor test.

 

I know where this is going to go. The AT-80 performance will be respectable on a better night, and I'll be tempted by an 80-90mm APO, break my vow to avoid acquisitions in 2024, and have to do some unspecified penance...

 

  

 

I remain steadfast in my opinion that everyone should have an FC-100.  It's nearly as light and easy to handle as a 60/76/80, sits happily on a simple AltAz mount like a Vixen Porta II,  and punches well above its aperture optically.  It's incredibly versatile and does everything well.  Mine is my cold, dead hands telescope, never to leave my side.

[Fiske]

I remain steadfast in my opinion that everyone should have an FC-100.  It's nearly as light and easy to handle as a 60/76/80, sits happily on a simple AltAz mount like a Vixen Porta II,  and punches well above its aperture optically.  It's incredibly versatile and does everything well.  Mine is my cold, dead hands telescope, never to leave my side.

Not helping!!!!!

 

Edited by Fiske, 11 January 2024 - 12:25 PM.

[Scott99]

That's a bargain for an FOA-60, which is the nicest 60 you can get anywhere, but it's still a 60.

 

 

I remain steadfast in my opinion that everyone should have an FC-100.  It's nearly as light and easy to handle as a 60/76/80, sits happily on a simple AltAz mount like a Vixen Porta II,  and punches well above its aperture optically.  It's incredibly versatile and does everything well.  Mine is my cold, dead hands telescope, never to leave my side.

Totally agree, I have many fond memories of years w/ my FS102.  Especially if you grew up reading Walter Scott Houston's observing notes with his 4" f/15 uncoated Clark, it's amazing how convenient it is nowadays to use a 4-inch refractor

[Erik Bakker]

Let me help Fiske, I had an FS-102 NSV, an optical stunner for sure. But I  prefer my ED82 for it’s rare combination of delightful optics and great grab-n-go ergonomics. It shows the most jaw-dropping views of the universe of all the scopes I ever had for it’s size and on some objects even irrelative of it’s small size. It has enough aperture to see wonderful detail on many objects and never feels lacking in that respect, unlike my 55mm and 70 mmm f/8 fluorites. The Tak FS-102 shows even more than all these of course, but is already much bigger and more at home on my Tak EM-10 equatorial, a great combination IME. Even today, after many years of use, I still wonder every night I use it under the stars how Nikon could make it this good. Many a time, I have to convince myself that I am observing at 75x instead of 30x. E.g., the stars are so small in the eyepiece, so tight and radiant with their spectral class colors that I often put on a small flashlight to make sure In cannot increase magnification. Because at 75x, it has reached the limit of magnification with it’s delightful native eyepieces. And yes, I have a full case of TeleVue and Zeiss eyepieces too. With scopes from Tak, Zeiss, Celestron, Vixen, Zeiss, Questar and Matthias Wirth.

 

And we’re talking a 10+ year old 82mm Nikon ED spotting scope here, which I use almost exclusively at night to observe the universe with instead of birds during the day