Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Differenced between 60mm refractors

Refractor
  • Please log in to reply
59 replies to this topic

#1 GGK

GGK

    Mariner 2

  • *****
  • topic starter
  • Posts: 272
  • Joined: 04 Jan 2021
  • Loc: SouthWest Florida

Posted 23 June 2021 - 06:15 PM

Long-time SCT user, short time on CN, and my first post in the refractor forum.

 

I've been reading a lot over the past few weeks about 60mm refractors, but do not really see threads that explain the difference between the various brands available or that make detailed comparisons.

 

I'm considering a small refractor that I can easily travel and hike with, but that I can also piggyback onto the top rail of my 9.25 inch SCT.  Visual use only, and I want to keep the weight low. The weight is the main reason I'm looking at 60mm.

 

Is there a major difference between a Televue 60mm vs. and AT60ED, vs. an Apertura 60EDR, for example?  Why is the Televue more expensive -  other than it's Televue?  Does one have any more capability than another?

 

I understand the aperture limitations on a 60mm scope.  During normal viewing sessions, my SCT has mid to high power covered, so I would use the refractor for objects larger than 1.2 degrees.

 

I also do a lot of short session viewing with my 16 x 50 binoculars and I'm thinking that a 60mm refractor on a light tripod might give a little more viewing capability and a more stable view for my run out for 20 minutes sessions.

 

Final question -- the many threads I've read are filled with people saying "I used to own...".  Why do so many people seem to sell their 60mm refractors even though they speak so highly about them? 

 

I will appreciate any experience, details and comparisons of the different brands that you can offer.

 

Thanks, Gary

 

 


  • Castor and teashea like this

#2 mac57

mac57

    Viking 1

  • *****
  • Posts: 623
  • Joined: 19 Feb 2013
  • Loc: DeLand of Oz, Florida

Posted 23 June 2021 - 06:27 PM

I think that in the current market, you get what you pay for.  I bought my first refractor a few months ago ( AT80ED) and love it for quality of build and performance.  To get really good optics, you have to pay.  I know a guy that has a 4" Stellarvue that would knock yer socks off.  If you want quality, patience in the used market is a good route.  Keep checking the Classifieds and get yer dream.  Mark


  • teashea and GGK like this

#3 Redbetter

Redbetter

    Voyager 1

  • *****
  • Posts: 10,940
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 23 June 2021 - 07:37 PM

With regards to people selling their 60's, there are a lot of scope owners and refractor owners in particular who flit from one scope to another, trying whatever is new, then going on to something else.  Folks do this with eyepieces as well, sometimes alternately buying and selling the same model several times.  It leaves me scratching my head, but some seem to find this satisfying.

 

On the other hand, a person might go to a 60 for the widest field, then pick up a 72 ED f/6, 80 f/5 (achro) or something else later and decide that it better suits their need, rendering the 60 superfluous.   There are various ways of accomplishing some of the same objectives.

 

The question is what does the observer (or imager) intend to do with the scope and under what conditions?  What other gear will that entail?

 

I don't doubt that the TV 60's are excellent and I wouldn't be surprised if they did better than the AT60ED's at high power, but they have 1.25" draw tubes.  So that puts a limit on wide field viewing of 4.3 degrees, and using 1.25" accessories (e.g. nebula filters.)  On the other hand the AT60's can do 7.3 degrees, but this requires a 2" diagonal, a massive 2" eyepiece and would require 2" nebula filters to take full advantage of it.  In this case, the scope is likely not the most expensive component.  But if a person already has the eyepieces and filters...  (Keep in mind there is loads of field curvature with such a wide true field and such a short focal length.)

 

In my case, I picked up the AT60ED to provide the widest possible field of view for the largest possible targets in dark sky.  I already had the eyepieces and accessories to make use of the lowest power/widest field as well as planetary/double star magnification.   Pleased with the results, I later added an AT72EDII, and in between I added an 80 f/5 achro that I modded with a 2" focuser/etc for rich field.  While they each do much of the same thing, they also have some applications for which I prefer one over another.  I am in no hurry to part with any of them.  


  • payner, M44, Castor and 2 others like this

#4 teashea

teashea

    Vanguard

  • *****
  • Posts: 2,120
  • Joined: 20 Dec 2020
  • Loc: Lincoln, Nebraska, USA

Posted 23 June 2021 - 08:03 PM

Long-time SCT user, short time on CN, and my first post in the refractor forum.

 

I've been reading a lot over the past few weeks about 60mm refractors, but do not really see threads that explain the difference between the various brands available or that make detailed comparisons.

 

I'm considering a small refractor that I can easily travel and hike with, but that I can also piggyback onto the top rail of my 9.25 inch SCT.  Visual use only, and I want to keep the weight low. The weight is the main reason I'm looking at 60mm.

 

Is there a major difference between a Televue 60mm vs. and AT60ED, vs. an Apertura 60EDR, for example?  Why is the Televue more expensive -  other than it's Televue?  Does one have any more capability than another?

 

I understand the aperture limitations on a 60mm scope.  During normal viewing sessions, my SCT has mid to high power covered, so I would use the refractor for objects larger than 1.2 degrees.

 

I also do a lot of short session viewing with my 16 x 50 binoculars and I'm thinking that a 60mm refractor on a light tripod might give a little more viewing capability and a more stable view for my run out for 20 minutes sessions.

 

Final question -- the many threads I've read are filled with people saying "I used to own...".  Why do so many people seem to sell their 60mm refractors even though they speak so highly about them? 

 

I will appreciate any experience, details and comparisons of the different brands that you can offer.

 

Thanks, Gary

There are differences in the quality of the design, construction and finish of 60mm refractors.  The resulting differences in optical quality are substantial.  I have four different Takahashi 60mm refractors and each is different in terms of the optical quality and its uses.  For purely optical quality, the Takahashi FOA60Q provides the best optical performance of an Takahashi, or any commercially available telescope.  But is longer than the others and one might want a telescope with a shorter length.  

 

Here are a couple of photos.

 

FS-60Q.jpg

 

172472727_10222028826204099_4544638028780655508_n.jpg

 

172567475_10222028825404079_5050053235414545495_n.jpg


Edited by teashea, 23 June 2021 - 08:05 PM.

  • BlueMoon, Castor, rerun and 3 others like this

#5 hyia

hyia

    Vostok 1

  • -----
  • Posts: 154
  • Joined: 07 Nov 2010

Posted 23 June 2021 - 08:35 PM

I think you really need to focus on the use case.  If I were getting it to take along traveling, hiking, bird watching, etc., I'd go with the Televue because it fits that the best IMO.  The trade-off is the helical focuser and, optically, it's not going to match up with the Tak FOA.  Roughly, I think of them as follows:

 

Spotting scope equivalent:  Televue 60, small, and tough.

Great optics:  Tak FOA 60, reputed to have the best optics but is a relatively long scope.

Astrophotography:  AT60, lots of reviews you can look at.  Cheap enough I wouldn't be gutted if it was damaged/lost in travel.

Mixed use:  Tak FS-60Q, without the Q-module, wouldn't be a bad as a spotting scope.  With the Q-module, not far behind the FOA.  I'd be a little worried about traveling with it because it is a little pricey although the flexibility and modular nature is attractive.  (I expect all my stuff to take abuse/be lost while traveling.)

 

This is just how I think of them, and I wouldn't claim any of this to be definitive.

 


  • Castor, Anthony236J, JeremySh and 1 other like this

#6 BlueMoon

BlueMoon

    Surveyor 1

  • *****
  • Posts: 1,598
  • Joined: 14 Jun 2007
  • Loc: South Central Idaho, USA

Posted 23 June 2021 - 08:50 PM

Long-time SCT user, short time on CN, and my first post in the refractor forum.

 

I've been reading a lot over the past few weeks about 60mm refractors, but do not really see threads that explain the difference between the various brands available or that make detailed comparisons.

 

I'm considering a small refractor that I can easily travel and hike with, but that I can also piggyback onto the top rail of my 9.25 inch SCT.  Visual use only, and I want to keep the weight low. The weight is the main reason I'm looking at 60mm.

 

Is there a major difference between a Televue 60mm vs. and AT60ED, vs. an Apertura 60EDR, for example?  Why is the Televue more expensive -  other than it's Televue?  Does one have any more capability than another?

 

I understand the aperture limitations on a 60mm scope.  During normal viewing sessions, my SCT has mid to high power covered, so I would use the refractor for objects larger than 1.2 degrees.

 

I also do a lot of short session viewing with my 16 x 50 binoculars and I'm thinking that a 60mm refractor on a light tripod might give a little more viewing capability and a more stable view for my run out for 20 minutes sessions.

 

Final question -- the many threads I've read are filled with people saying "I used to own...".  Why do so many people seem to sell their 60mm refractors even though they speak so highly about them? 

 

I will appreciate any experience, details and comparisons of the different brands that you can offer.

 

Thanks, Gary

Suggestion: make it simple on yourself. Choose: apochromat or achromat. Choose: doublet or triplet. That's pretty much it. Once you have these two answers, it helps define your choice(s) for a 60mm scope.

 

Why people sell their gear, 60mm scopes and telescope brand not withstanding, is as myriad a number of reasons as why they bought it in the first place. There is no definitive answer.

 

Clear skies.


Edited by BlueMoon, 23 June 2021 - 10:14 PM.

  • Jon_Doh, BFaucett, teashea and 1 other like this

#7 Parsonsk

Parsonsk

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 01 Mar 2020

Posted 24 June 2021 - 12:26 AM

what do you think of the SharpStar 76 or 61

 

and do you think the jump up to the 76 from the 61 is worth it?



#8 M44

M44

    Viking 1

  • *****
  • Posts: 803
  • Joined: 24 Mar 2007
  • Loc: Southern California

Posted 24 June 2021 - 12:36 AM

 

 

I also do a lot of short session viewing with my 16 x 50 binoculars and I'm thinking that a 60mm refractor on a light tripod might give a little more viewing capability and a more stable view for my run out for 20 minutes sessions.

 

Final question -- the many threads I've read are filled with people saying "I used to own...".  Why do so many people seem to sell their 60mm refractors even though they speak so highly about them? 

 

You are absolutely right about 60mm being more versatile than a 16x50 binocular.  I really appreciate the steady views of a 60mm refractor after using my 18x70 binocular.  

 

For traveling, hiking etc, I would suggest between

 

  - doublet and triplet => doublet (examples: AT60ED, Televue 60, Takahashi FS-60CB/CQ)

  - f/6 or longer => f/6 (AT60ED, Televue 60, Takahashi FS-60CB)

  - 2" focuser or 1.25"  =>  (Televue 60, Takahashi FS-60CB) 

  - ED or Achromat => ED (Televue 60, Takahashi FS-60CB)

  

 Now I own AT60ED, because of it is compact and comes with 2" focuser. But it would be heavy to carry a 2" diagonal and eyepieces. For traveling it may not make a difference but for hiking it would be heavy. 

 

I used to own :-), Takahashi FS-60CB/CQ. It is a fantastic performer and I have many memorable views of Milkyway at a dark skies after converting it to accept 2" diagonal. I liked it so much and hated it so much, I bought and sold this scope 3 times. I might buy it again. 

 

The main issue with small scopes is the balance when using 2" diagonal and heavier eyepieces.  My AT60ED is capable of handling the load with ease.

 

I also own a 80mm f/5 achromat and it will be a good choice for hiking and traveling and brighter views of DSOs. Many Orion short tube 80mm and clones are discontinued but there a couple I see.

 

Celestron 80mm f/5

 

IOptron 80mm f/5

 

Edit: I suggested 80mm f/5 , because it is lighter than many 60mm scopes and close to the focal length of 60mm f/6 scopes. 

 

 

 

 - 


Edited by M44, 24 June 2021 - 12:50 AM.

  • JeremySh and GGK like this

#9 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 93,703
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 24 June 2021 - 05:30 AM

My thinking:

 

A 60mm is a "niche" scope.  As a companion for a larger scope, I think an 80mm is a better choice.  It's still compact, it's still grab and go but it's a better balance between aperture and field of view.  A 60mm F/6 can do a 7.3 degree field of view with a 41mm Panoptic but that's at 8.8x.  An 80mm F/6 can do 5.5 degrees at 11.7x, plenty for most purposes.  

 

The field curvature of a 60mm F/6 with those wide fields is major, the stars at the edge are way out of focus. The difference between center focus and edge focus with an eyepiece like the 41mm Panoptic that maximizes the field of view is over 2 mm. Stars are not clean and round.  To get clean round stars, that's takes a TSFLAT2, another $200 and an appropriate diagonal and some messing around.  The 80mm F/6 will also have field curvature, not as much.

 

At higher magnifications, the 60mm takes quite a hit which compared to the 80mm.  As a grab and go scope, the 80mm is more versatile. 

 

I don't have a 60mm F/6.  These scopes are best suited for low power, wide field observing.  In my mind, for low power, wide field, an 80mm F/5 achromat is a better choice.  The focal length is 40mm longer so the maximum possible field of view is "only 6.6 degrees", more than enough for nearly all practical purposes.  And the added 20mm of aperture means the images are 78% brighter at the same magnification, a big advantage since the most often those big wide fields are used with deep sky filters and the brighter image is a big help.  

 

In Gary's situation, I would be looking at an 80mm.. 

 

Jon


  • Alan French, BlueMoon, knight_parn and 1 other like this

#10 BlueMoon

BlueMoon

    Surveyor 1

  • *****
  • Posts: 1,598
  • Joined: 14 Jun 2007
  • Loc: South Central Idaho, USA

Posted 24 June 2021 - 09:54 AM

+1 What Jon said. waytogo.gif



#11 GGK

GGK

    Mariner 2

  • *****
  • topic starter
  • Posts: 272
  • Joined: 04 Jan 2021
  • Loc: SouthWest Florida

Posted 24 June 2021 - 02:30 PM

My thinking:

 

A 60mm is a "niche" scope.  As a companion for a larger scope, I think an 80mm is a better choice.  It's still compact, it's still grab and go but it's a better balance between aperture and field of view.  A 60mm F/6 can do a 7.3 degree field of view with a 41mm Panoptic but that's at 8.8x.  An 80mm F/6 can do 5.5 degrees at 11.7x, plenty for most purposes.  

 

The field curvature of a 60mm F/6 with those wide fields is major, the stars at the edge are way out of focus. The difference between center focus and edge focus with an eyepiece like the 41mm Panoptic that maximizes the field of view is over 2 mm. Stars are not clean and round.  To get clean round stars, that's takes a TSFLAT2, another $200 and an appropriate diagonal and some messing around.  The 80mm F/6 will also have field curvature, not as much.

 

At higher magnifications, the 60mm takes quite a hit which compared to the 80mm.  As a grab and go scope, the 80mm is more versatile. 

 

I don't have a 60mm F/6.  These scopes are best suited for low power, wide field observing.  In my mind, for low power, wide field, an 80mm F/5 achromat is a better choice.  The focal length is 40mm longer so the maximum possible field of view is "only 6.6 degrees", more than enough for nearly all practical purposes.  And the added 20mm of aperture means the images are 78% brighter at the same magnification, a big advantage since the most often those big wide fields are used with deep sky filters and the brighter image is a big help.  

 

In Gary's situation, I would be looking at an 80mm.. 

 

Jon

 

 

You are absolutely right about 60mm being more versatile than a 16x50 binocular.  I really appreciate the steady views of a 60mm refractor after using my 18x70 binocular.  

 

For traveling, hiking etc, I would suggest between

 

  - doublet and triplet => doublet (examples: AT60ED, Televue 60, Takahashi FS-60CB/CQ)

  - f/6 or longer => f/6 (AT60ED, Televue 60, Takahashi FS-60CB)

  - 2" focuser or 1.25"  =>  (Televue 60, Takahashi FS-60CB) 

  - ED or Achromat => ED (Televue 60, Takahashi FS-60CB)

  

 Now I own AT60ED, because of it is compact and comes with 2" focuser. But it would be heavy to carry a 2" diagonal and eyepieces. For traveling it may not make a difference but for hiking it would be heavy. 

 

I used to own :-), Takahashi FS-60CB/CQ. It is a fantastic performer and I have many memorable views of Milkyway at a dark skies after converting it to accept 2" diagonal. I liked it so much and hated it so much, I bought and sold this scope 3 times. I might buy it again. 

 

The main issue with small scopes is the balance when using 2" diagonal and heavier eyepieces.  My AT60ED is capable of handling the load with ease.

 

I also own a 80mm f/5 achromat and it will be a good choice for hiking and traveling and brighter views of DSOs. Many Orion short tube 80mm and clones are discontinued but there a couple I see.

 

Celestron 80mm f/5

 

IOptron 80mm f/5

 

Edit: I suggested 80mm f/5 , because it is lighter than many 60mm scopes and close to the focal length of 60mm f/6 scopes. 

 

 

 

 - 

 

 

Suggestion: make it simple on yourself. Choose: apochromat or achromat. Choose: doublet or triplet. That's pretty much it. Once you have these two answers, it helps define your choice(s) for a 60mm scope.

 

Why people sell their gear, 60mm scopes and telescope brand not withstanding, is as myriad a number of reasons as why they bought it in the first place. There is no definitive answer.

 

Clear skies.

 

 

I think you really need to focus on the use case.  If I were getting it to take along traveling, hiking, bird watching, etc., I'd go with the Televue because it fits that the best IMO.  The trade-off is the helical focuser and, optically, it's not going to match up with the Tak FOA.  Roughly, I think of them as follows:

 

Spotting scope equivalent:  Televue 60, small, and tough.

Great optics:  Tak FOA 60, reputed to have the best optics but is a relatively long scope.

Astrophotography:  AT60, lots of reviews you can look at.  Cheap enough I wouldn't be gutted if it was damaged/lost in travel.

Mixed use:  Tak FS-60Q, without the Q-module, wouldn't be a bad as a spotting scope.  With the Q-module, not far behind the FOA.  I'd be a little worried about traveling with it because it is a little pricey although the flexibility and modular nature is attractive.  (I expect all my stuff to take abuse/be lost while traveling.)

 

This is just how I think of them, and I wouldn't claim any of this to be definitive.

Thanks to everyone for your replies.

 

Weight is concern, both for grab and go as well as mounting on top of my SCT.  Since this is for visual only, a doublet is all I need.  I don't have the experience to know if I will notice the difference between and Achromat vs. an APO, for visual use.  I have plenty of experience with field curvature, though, pushing my SCTs out to 2 degrees.  Minimizing field curvature is always a positive.

 

I prefer the larger 80mm aperture if the weight is about the same and the length is manageable.  However, when I Google search for 80mm f/5 refractors, I only see the ones like the Celestron and iOptron above that say they're for kids and beginners. I also saw a used Meade 80mm that looked the same as the iOptron.   Are these decent refractors or am I not finding what you are suggesting?  The weight is definitely nice at 3 pounds (iOptron 80mm description).    

 

Also, the 80mm f/5 refractors appear to all have a 1-1/4 focuser.  The 41 Pan mentioned above for the wider views was with a 80mm f/6.  The 80mm f/6 Achromat doublets I found with a search all weighed nearly 2.5x as much.   Are there any 80mm f/6 OTAs in the 4 to 5 pound range?  The additional 3+ inches in length is workable if the weight doesn't increase too much.

 

Finally, I know I can step between a 60mm and 80mm with something like the AT7ED f/6 at 4.8 pounds and get a 2 inch focuser if I decide that's best for my needs.  Is there a general price point where a little better quality smaller 72mm aperture will outperform the 80mm f/5 scopes above?

 

Thanks,  Gary


  • teashea likes this

#12 GGK

GGK

    Mariner 2

  • *****
  • topic starter
  • Posts: 272
  • Joined: 04 Jan 2021
  • Loc: SouthWest Florida

Posted 24 June 2021 - 02:37 PM

 

In my case, I picked up the AT60ED to provide the widest possible field of view for the largest possible targets in dark sky.  I already had the eyepieces and accessories to make use of the lowest power/widest field as well as planetary/double star magnification.   Pleased with the results, I later added an AT72EDII, and in between I added an 80 f/5 achro that I modded with a 2" focuser/etc for rich field.  While they each do much of the same thing, they also have some applications for which I prefer one over another.  I am in no hurry to part with any of them.  

RedBetter,

 

So you started with the AT60ED, then bought the 80mm f5 Achro that you adapted for a 2 inch focuser.  What does the 72mm you bought later give you that is not already covered by these two?  No challenge in my question - I'm really just trying to learn about these smaller refractors and what to expect from them.

Gary



#13 GGK

GGK

    Mariner 2

  • *****
  • topic starter
  • Posts: 272
  • Joined: 04 Jan 2021
  • Loc: SouthWest Florida

Posted 24 June 2021 - 02:45 PM

You are absolutely right about 60mm being more versatile than a 16x50 binocular.  I really appreciate the steady views of a 60mm refractor after using my 18x70 binocular.  

 

 

My 16 x 50 binoculars are about as much magnification as I can handle without support.  I'm already at the edge of being too unsteady without leaning on something.

 

Have you ever tried a monopod with your 18x70s?  I was looking at those before I started considering a small refractor.

 

I wonder if anyone has ever tried a monopod with a small refractor with wide field views. It would definitely be more portable than packing a tripod.



#14 M44

M44

    Viking 1

  • *****
  • Posts: 803
  • Joined: 24 Mar 2007
  • Loc: Southern California

Posted 24 June 2021 - 02:59 PM

My 16 x 50 binoculars are about as much magnification as I can handle without support.  I'm already at the edge of being too unsteady without leaning on something.

 

Have you ever tried a monopod with your 18x70s?  I was looking at those before I started considering a small refractor.

 

I wonder if anyone has ever tried a monopod with a small refractor with wide field views. It would definitely be more portable than packing a tripod.

I use zero gravity chair and hold them at the barrel ends briefly for observing. I tried monopod with 10x50 long time ago, didn't like. 

 

I use observing chair and hands off the tripod/scope when observing, monopod is not practical for me. 


  • GGK likes this

#15 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 93,703
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 24 June 2021 - 03:14 PM

Gary:

 

80 mm F/5 achrmats come with 1.25 inch focusers, they have to be upgraded. The standard is the GSO two speed for $135.

 

This is my ST-80.  I also have 80mm F/6 and F/7 ED doublets.

 

Celestron ST-80.jpg
 
Jon

  • GGK likes this

#16 gwlee

gwlee

    Mercury-Atlas

  • *****
  • Posts: 2,838
  • Joined: 06 Sep 2015
  • Loc: 38N 120W

Posted 24 June 2021 - 04:16 PM

The AT60ED has a 2-inch focuser, so it can use 2” accessories, making it more versatile than the TV 60 and costs 1/2 as much. The TV 60 is limited to 1.25” eyepieces, but it’s probably the lightest most compact 60mm available.

 

I replaced TV 60 with an AT72ED2, because I didn’t need quite as much portability as TV 60 offers, and wanted a bit more aperture along with a 2” focuser. The TV 60 costs about twice as much, and doesn’t perform as well, but I would have kept it I needed it’s greater portability. The AT72EDII IS excellent for tree dodging, travel, and suitable for hiking a mile or two from my home to catch a celestial event that I can’t see from home. 

There’s no doubt an 80mm scope offers more performance, but it’s a bigger and heavier scope scope that requires a bigger and heavier mount to be as well mounted, and it’s usually more expensive than a smaller scope. However, If I didn’t have an 92mm scope, I would probably replace my 72mm scope with an 80 because it’s portable enough to meet my needs now and definitely offers more performance. 
 

Basically, selecting between small refractors come down to a choice between performance and portability, which usually gets you a wider FOV too. All are modest performers though, so I recommend choosing based on your portability requirements. 
 

Small good quality ED doublets have become so inexpensive that I wouldn’t buy an achromat these days, which usually don’t have the same build quality in addition to chromatic aberration. 


Edited by gwlee, 24 June 2021 - 04:19 PM.

  • Jon Isaacs and GGK like this

#17 GOLGO13

GOLGO13

    Fly Me to the Moon

  • *****
  • Posts: 6,027
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 24 June 2021 - 04:36 PM

Maybe I lucked out, but my AT60 current version is as good as the Televue 60mm and the Takashi 60mm. I sold the TV60 because it was. I just got the Takahashi 60mm and got the Q module to make it F10. Obviously that helps a bit with field curvature and such.

Honestly, the AT60 I have is the best of the 3. Again, I may have lucked out. It was one of the first batch of AT60EDs. But the TAK60 does provide some flexibility with being F10 or F6, I have white light and Hydrogen Alpha filters for solar for it.

These are great scopes for ultimate portability especially when you consider a mount. Great for solar and spotting scopes. Great for lunar and planetary, but obviously limited in aperture. They are sharp at high magnification but run out of light eventually. Good to pair with a 3 to 6 zoom.
  • BFaucett and GGK like this

#18 GOLGO13

GOLGO13

    Fly Me to the Moon

  • *****
  • Posts: 6,027
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 24 June 2021 - 04:48 PM

I do agree that 60mm is pretty small aperture.  Really it's best for situations where light weight and or extreme portability is needed. But I do admit they are fun to use and are better than some folks may realize.  Just have to have the right expectations.  But I find 80mm is limited in aperture also. But they have a place for grab and go portabilty. 


  • Jon Isaacs, BFaucett and GGK like this

#19 GGK

GGK

    Mariner 2

  • *****
  • topic starter
  • Posts: 272
  • Joined: 04 Jan 2021
  • Loc: SouthWest Florida

Posted 24 June 2021 - 05:42 PM

 

Gary:

 

80 mm F/5 achromats come with 1.25 inch focusers, they have to be upgraded. The standard is the GSO two speed for $135.

 

This is my ST-80.  I also have 80mm F/6 and F/7 ED doublets.

 

 
 
Jon

 

Jon,

 

Thanks. The picture really helped.  I could not tell by the vendor pics that the focuser could be upgraded.  I already have 2 inch accessories.  Is the GSO upgrade an easy switch or is it something you only want to do once?  The reason I ask is because the ST-80 design with the stock focuser is as light as the 60mm achromats I was looking at, but the 2 inch focuser will add a little more weight.  I was wondering if I can easily go back to the 1-1/4 focuser if needed to keep the weight to a minimum for back-packing.  When going for lightest pack weight, I might want to stay with the 1-1/4 diagonal and light weight eye pieces. But I think I would like the wider-field capability with a 2-inch set up when the ST80 is piggy-backed onto the bigger SCT.  

 

Thanks, Gary



#20 GGK

GGK

    Mariner 2

  • *****
  • topic starter
  • Posts: 272
  • Joined: 04 Jan 2021
  • Loc: SouthWest Florida

Posted 24 June 2021 - 06:23 PM

I searched CN for focusers for the St-80 and found this very informative discussion that answers most of my questions:  

 

https://www.cloudyni...m-f5-refractor/

 

There are some comments regarding the different ST-80 type brands as well as comments comparing to the AT72ED.  



#21 Redbetter

Redbetter

    Voyager 1

  • *****
  • Posts: 10,940
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 24 June 2021 - 06:44 PM

RedBetter,

 

So you started with the AT60ED, then bought the 80mm f5 Achro that you adapted for a 2 inch focuser.  What does the 72mm you bought later give you that is not already covered by these two?  No challenge in my question - I'm really just trying to learn about these smaller refractors and what to expect from them.

Gary

The AT60ED gave me the absolute max true field of view for a well corrected refractor, and the smallest overall package.  It also is the most forgiving of a light mount.  For taking in as much as possible of Barnard's Loop all at once, this is the one for me.  Ditto for the Lambda Orionis nebula (Angelfish.)  It can also do some light planetary, and partially resolve the brighter globulars at high power.  It is the most airline portable of what I have, although I have not used it that way...so far.  I still would like to see the Large and Small Magellanic clouds through it.  

 

The 80 f/5 (Meade Adventure Scope which is an ST80 clone with different colors/badging) was a pleasant surprise since it has decent optics.  My ST80 has some aberrations, but makes an excellent finder on the 20" and sees some service at moderate powers as well.  So when I realized that this particular sample of Meade 80 f/5 had a good figure, I decided to take full advantage of it by adding a 2" GSO two speed focuser--which could be had for $86 delivered at the time.   I added rings, and moved the internal tube baffle back to maximize the fully illuminated field.  

 

In practice the 80 f/5 achro is a mix visually.  This sample is capable of some planetary, but of course that is still its weakness.  The chromatic aberration is such that the AT60ED is preferable for high power viewing, lunar and planetary.  Some of this is aesthetic, but there is loss of fine detail to CA which results in the 80 achro performing more like a 60ED at high power.  (Filters don't fix the loss of fine detail from CA in my experience.)   

 

Of course, I didn't buy the achro for planetary or high power.  I bought it for rich field; any other capability is just bonus.  While I can use a 41 Pan for ~6.6 deg true field of view, the result is an 8.2mm pupil.  The result is that my eye's pupil will effectively stop the scope down to some extent.  So a better pairing is the 31 Nagler for 6.0 degrees and a 6.2mm pupil.  There is still a lot of field curvature inherent to the scope's short focal length.  It does quite well with filters on large nebulae complexes.  The extra aperture helps in this regard, so for all but the most gargantuan nebulae it has an advantage. 

 

The 80 f/5 with 2" focuser, rings, and its fixed dew shield is considerably bulkier than the AT60ED or even the AT72EDII.  It is still a lot smaller than the ubiquitous ED80 f/7.5.  The ED80's are great optically, but they have fixed dew shields, and the tube ID is actually for a 100mm objective.  Therefore they have not been optimized for portability/travel.  And of course the focal length of the ED80 is considerably longer.

 

I am finding the AT72EDII is somewhat of a Goldilocks scope between the AT60ED and the 80 f/5 achro in 2".  It isn't quite as small as the 60, but it fits in the same size Apache 3800 case with 2" diagonal and RDF.   It provides more resolution than the 60 and is better at planetary than the 80 f/5 achro.  At f/6 it is a better match for the 41 Pan than the 80 f/5, providing 6.1 deg true field and 6.8mm pupil. 

 

The net result is that the 72EDII has been getting a lot more use than I thought it would.  When I needed something to put in the car quickly and find a spot along the road up the mountain for the Jupiter-Saturn conjunction, it provided the best balance.  When I was tracing the Eridanus super bubble during a DSO session beside the 20", it became the tool of choice over the other refractors I could have brought.  I wanted somewhat more light than the 60 was bringing in. The 80 might have done even better for this, but the 72 was more conveniently packaged.  Seeing in the backyard is usually pretty bad this time, with vigorous twinkle to the stars, so a small scope has an edge most of the time since there won't be much to see.  The 72 is more convenient than the ED80 for quick looks at planets in the backyard, so the 72 is on a light mount near the door.  If the seeing is better then bigger scopes than the 72 or 80 will come out...unfortunately that hasn't been worthwhile in recent months.


Edited by Redbetter, 25 June 2021 - 12:02 AM.

  • ewave, BFaucett, NYJohn S and 1 other like this

#22 daquad

daquad

    Vanguard

  • *****
  • Posts: 2,025
  • Joined: 14 May 2008

Posted 24 June 2021 - 06:45 PM

Thanks to everyone for your replies.

 

Weight is concern, both for grab and go as well as mounting on top of my SCT.  Since this is for visual only, a doublet is all I need.  I don't have the experience to know if I will notice the difference between and Achromat vs. an APO, for visual use.  I have plenty of experience with field curvature, though, pushing my SCTs out to 2 degrees.  Minimizing field curvature is always a positive.

 

I prefer the larger 80mm aperture if the weight is about the same and the length is manageable.  However, when I Google search for 80mm f/5 refractors, I only see the ones like the Celestron and iOptron above that say they're for kids and beginners. I also saw a used Meade 80mm that looked the same as the iOptron.   Are these decent refractors or am I not finding what you are suggesting?  The weight is definitely nice at 3 pounds (iOptron 80mm description).    

 

Also, the 80mm f/5 refractors appear to all have a 1-1/4 focuser.  The 41 Pan mentioned above for the wider views was with a 80mm f/6.  The 80mm f/6 Achromat doublets I found with a search all weighed nearly 2.5x as much.   Are there any 80mm f/6 OTAs in the 4 to 5 pound range?  The additional 3+ inches in length is workable if the weight doesn't increase too much.

 

Finally, I know I can step between a 60mm and 80mm with something like the AT7ED f/6 at 4.8 pounds and get a 2 inch focuser if I decide that's best for my needs.  Is there a general price point where a little better quality smaller 72mm aperture will outperform the 80mm f/5 scopes above?

 

Thanks,  Gary

True for the 80 mm Achro's..  But the Orion 80 mm f/7.5 ED (~500$) has a 2" focuser and with a wide field eyepiece can deliver wide field views in excess of 4 degrees, more than enough for most RFT observing.  You won't even need a

finder, although you have to buy a set of rings.  

 

Dom Q.


  • GGK likes this

#23 GGK

GGK

    Mariner 2

  • *****
  • topic starter
  • Posts: 272
  • Joined: 04 Jan 2021
  • Loc: SouthWest Florida

Posted 24 June 2021 - 07:02 PM

 

The AT60ED has a 2-inch focuser, so it can use 2” accessories, making it more versatile than the TV 60 and costs 1/2 as much. The TV 60 is limited to 1.25” eyepieces, but it’s probably the lightest most compact 60mm available.

 

I replaced TV 60 with an AT72ED2, because I didn’t need quite as much portability as TV 60 offers, and wanted a bit more aperture along with a 2” focuser. The TV 60 costs about twice as much, and doesn’t perform as well, but I would have kept it I needed it’s greater portability. The AT72EDII IS excellent for tree dodging, travel, and suitable for hiking a mile or two from my home to catch a celestial event that I can’t see from home. 

There’s no doubt an 80mm scope offers more performance, but it’s a bigger and heavier scope scope that requires a bigger and heavier mount to be as well mounted, and it’s usually more expensive than a smaller scope. However, If I didn’t have an 92mm scope, I would probably replace my 72mm scope with an 80 because it’s portable enough to meet my needs now and definitely offers more performance. 
 

Basically, selecting between small refractors come down to a choice between performance and portability, which usually gets you a wider FOV too. All are modest performers though, so I recommend choosing based on your portability requirements. 
 

Small good quality ED doublets have become so inexpensive that I wouldn’t buy an achromat these days, which usually don’t have the same build quality in addition to chromatic aberration. 

 

The AT72ED2 is one of the options I'm looking at.  Per the Astronomics website, it's 4.8 pounds with the rings and dovetail.  In another thread I read that the ST-80 with a 2-inch focuser and rings is 4.5 pounds, so about the same.  The AT72ED2 is nearly $200 more, but I am guessing that it gives a better view for visual on everything, except the times when the extra aperture really matters.  

 

It's hard to beat a 3+ pound shorter scope for back packing, though, which is why I'm back and forth on this.  It's why in my opening post I asked for a comparison between the TV-60, the AT60ED and the Apertura 60EDR.  I like the 2 inch focuser on the AT and Apertura and they're half the price of the Televue and maybe only another half pound. But realistically, probably 85% of the time I will use the refractor as a rich field combination with my SCT or a stand-alone running around my yard, and the extra pound won't matter.  

 

I liked your tree dodging comment.  Before setting up my SCT, I always use an App to review the tracks of the main objects I plan to view.  Even a few feet of movement can make a difference. By doing this, I can see Omega Centauri in a V between two trees.  I get about 20 minutes viewing time, so planning and position is everything.


  • BFaucett and teashea like this

#24 teashea

teashea

    Vanguard

  • *****
  • Posts: 2,120
  • Joined: 20 Dec 2020
  • Loc: Lincoln, Nebraska, USA

Posted 24 June 2021 - 07:13 PM

Thanks to everyone for your replies.

 

Weight is concern, both for grab and go as well as mounting on top of my SCT.  Since this is for visual only, a doublet is all I need.  I don't have the experience to know if I will notice the difference between and Achromat vs. an APO, for visual use.  I have plenty of experience with field curvature, though, pushing my SCTs out to 2 degrees.  Minimizing field curvature is always a positive.

 

I prefer the larger 80mm aperture if the weight is about the same and the length is manageable.  However, when I Google search for 80mm f/5 refractors, I only see the ones like the Celestron and iOptron above that say they're for kids and beginners. I also saw a used Meade 80mm that looked the same as the iOptron.   Are these decent refractors or am I not finding what you are suggesting?  The weight is definitely nice at 3 pounds (iOptron 80mm description).    

 

Also, the 80mm f/5 refractors appear to all have a 1-1/4 focuser.  The 41 Pan mentioned above for the wider views was with a 80mm f/6.  The 80mm f/6 Achromat doublets I found with a search all weighed nearly 2.5x as much.   Are there any 80mm f/6 OTAs in the 4 to 5 pound range?  The additional 3+ inches in length is workable if the weight doesn't increase too much.

 

Finally, I know I can step between a 60mm and 80mm with something like the AT7ED f/6 at 4.8 pounds and get a 2 inch focuser if I decide that's best for my needs.  Is there a general price point where a little better quality smaller 72mm aperture will outperform the 80mm f/5 scopes above?

 

Thanks,  Gary

The Takahashi  FC76DS is one you might consider if you want to step up in size from a 60mm.  There are quite a number of reports about it here on CN.  I have two of them and find it to be a very nice telescope.

 

177581259_10222081005548550_2843867916166275145_n.jpg


  • rerun, jena100 and GGK like this

#25 GGK

GGK

    Mariner 2

  • *****
  • topic starter
  • Posts: 272
  • Joined: 04 Jan 2021
  • Loc: SouthWest Florida

Posted 24 June 2021 - 07:19 PM

The AT60ED gave me the absolute max true field of view for a well corrected refractor, and the smallest overall package.  It also is the most forgiving of a light mount.  For taking in as much as possible of Barnard's Loop all at once, this is the one for me.  Ditto for the Lambda Orionis nebula (Angelfish.)  It can also do some light planetary, and partially resolve the brighter globulars at high power.  It is the most airline portable of what I have, although I have not used it that way...so far.  I still would like to see the Large and Small Magellanic clouds through it.  

 

The 80 f/5 (Meade Adventure Scope which is an ST80 clone with different colors/badging) was a pleasant surprise since it has decent optics.  My ST80 has some aberrations, but makes an excellent finder on the 20" and sees some service at moderate powers as well.  So when I realized that this particular sample of Meade 80 f/5 had a good figure, I decided to take full advantage of it by adding a 2" GSO two speed focuser--which could be had for $86 delivered at the time.   I added rings, and moved the internal tube baffle back to maximize the fully illuminated field.  

 

In practice the 80 f/5 achro is a mix visually.  This sample is capable of some planetary, but of course that is still its weakness.  The chromatic aberration is such that the AT60ED is preferable for high power viewing, lunar and planetary.  Some of this is aesthetic, but their is loss of fine detail to CA which results in the 80 achro performing more like a 60ED at high power.  (Filters don't fix the loss of fine detail from CA in my experience.)   

 

Of course, I didn't buy the achro for planetary or high power.  I bought it for rich field; any other capability is just bonus.  While I can use a 41 Pan for ~6.6 deg true field of view, the result is an 8.2mm pupil.  The result is that my eye's pupil will effectively stop the scope down to some extent.  So a better pairing is the 31 Nagler for 6.0 degrees and a 6.2mm pupil.  There is still a lot of field curvature inherent to the scope's short focal length.  It does quite well with filters on large nebulae complexes.  The extra aperture helps in this regard, so for all but the most gargantuan nebulae it has an advantage. 

 

The 80 f/5 with 2" focuser, rings, and its fixed dew shield is considerably bulkier than the AT60ED or even the AT72EDII.  It is still a lot smaller than the ubiquitous ED80 f/7.5.  The ED80's are great optically, but they have fixed dew shields, and the tube ID is actually for a 100mm objective.  Therefore they have not been optimized for portability/travel.  And of course the focal length of the ED80 is considerably longer.

 

I am finding the AT72EDII is somewhat of a Goldilocks scope between the AT60ED and the 80 f/5 achro in 2".  It isn't quite as small as the 60, but it fits in the same size Apache 3800 case with 2" diagonal and RDF.   It provides more resolution than the 60 and is better at planetary than the 80 f/5 achro.  At f/6 it is a better match for the 41 Pan than the 80 f/5, providing 6.1 deg true field and 6.8mm pupil. 

 

The net result is that the 72EDII has been getting a lot more use than I thought it would.  When I needed something to put in the car quickly and find a spot along the road up the mountain for the Jupiter-Saturn conjunction, it provided the best balance.  When I was tracing the Eridanus super bubble during a DSO session beside the 20", it became the tool of choice over the other refractors I could have brought.  I wanted somewhat more light than the 60 was bringing in. The 80 might have done even better for this, but the 72 was more conveniently packaged.  Seeing in the backyard is usually pretty bad this time, with vigorous twinkle to the stars, so a small scope has an edge most of the time since there won't be much to see.  The 72 is more convenient than the ED80 for quick looks at planets in the backyard, so the 72 is on a light mount near the door.  If the seeing is better then bigger scopes than the 72 or 80 will come out...unfortunately that hasn't been worthwhile in recent months.

This is great information.  Thank you.  It hits on my main objectives for buying the refractor. 

 

As I said to gwlee above, although I'm looking for a light weight backpacking scope ( which will include flights), probably the majority of the time I will be using it in my yard or around the neighborhood.  When I wrote my opening post, I was thinking only about piggybacking the refractor to my SCT when at home which I will do, of course, because it's a very nice compliment.  However, now that I've had comments from people who actually use the scopes and know what they're talking about, I can see that I might also use it more during the summer months at home on it's own light weight mount.  I live in southwest Florida in fairly dark and usually pretty stable skies.  We have two seasons - dry and wet.  Summer starts the wet season, so my viewing goes more to 30 minute sessions between rain clouds with the binoculars.  These small refractors sound like they're convenient enough and also good enough to use during those short opportunities.  My initial thought without knowing better was that they were at least better than binoculars when hiking.  But I am now starting to get a much better opinion about their potential value to my viewing.


  • teashea likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: Refractor



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics