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Thoughts On The Refractor?

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#1 -Starfighter-

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Posted 06 August 2014 - 11:01 AM

Hi All,

 

Admittedly my experience with the small refractor is limited, however I think I have just had an epiphany on these scopes. Although I affectionately call the refractor the 4x4 of scopes due to its ease of use and grab-n-go factor I am starting to think that it is not an ideal scope to separate stars on globular clusters and look for feint fuzzies. I have read a great deal about the comparisons between the refractor vs reflector debate and I am just not so sure that a refractor can get the detail due to the lack of light grasp. I am now spoiled with the views I get through my Orion 10" and am skeptical that I will be able to make out the same detail through a refractor with substantially less light grasp. I had my Skywatcher 120mm out at a dark site with good seeing last week and I turned the scope to one of my favorite globulars M13. I can say it was just not impressive. Once you have spent time with a light cannon you are spoiled... I have enjoyed the scope for solar system viewing with it's crisp high contrast views (with CA) but it seems beyond that I am just not going to get much use from it. I am starting to think if I want to have the impressive views where I can resolve the stars in clusters I am going to have to be at a 8" CAT min. Perhaps I will have to sell it and look for a new set up. I think I am still going to want to have an apo in my collection in the future but I am now skeptical that it's going to be the scope that gets used the most. It's seems refractors large and small have a strong following, however is this because of the contrast, use for AP,or FOV because visually I am not sure they can provide the detailed views of DSO's...

 

I had some passers by look into the scope and even they were not impressed! If it was my 10" they would have spent much more time at the ep....

 

Should I be looking at TAK's and the like for that visual wow experience, or just stick with the cheaper designs and get all that aperture?

Why are people so enamored with small refractors when they can't get that detail (visual)?

 

Thoughts?



#2 RussL

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Posted 06 August 2014 - 11:52 AM

For me:  I am old with health issues, so my refractors are what keep me going out the door due to their light weight.  I do miss the detail of larger aperture, but...  I am also in a red zone and have come to enjoy richfield observing of brighter objects, so my refractors show me a good time at low mags with a large FOV.  Of course, the brighter planets would still be doable with any aperture in a red zone, but I have to give up something in the mix.  Richfield observing has given me a new look on everything, so I am like a kid again out there seeing things in a new way.  I'd love a 12" or larger, but it wouldn't get much use to due the hassle of moving it around.  And that's another thing, I have to move around the yard a lot, too.  so, I'm happy with smallis refractors these days.



#3 Astrojensen

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Posted 06 August 2014 - 12:02 PM

 

 

Why are people so enamored with small refractors when they can't get that detail (visual)?

Because we get other things in return. 

 

 

Clear skies!
Thomas, Denmark


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#4 Scott99

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Posted 06 August 2014 - 12:07 PM

Even the best 120mm refractor isn't going to compete well with a 10 inch reflector.   I've seen better views of M13 through Orion's 6-inch f/8 dob than in my 120mm apo.  The smaller refractors are easy to set up and use though.  No collimation worries and nice sharp views.  I can use the 120mm apo on a Teegul alt-az mount and get most objects in the FOV by siting along the tube with no finder.   These scopes can do amazing things on the planets too.

 

I think a 6-inch refractor can give rewarding deep-sky views compared to a 10-inch.   6-inch refractor is probably the smallest one to be considered a serious deep-sky instrument.   It will still give up some brightness to the 10-inch and won't do as well on objects with low surface brightness.  But the crisp clarity of the views can make up for it.   If I only had one scope it would have to be at least a 6-inch refractor.  The smaller ones complement bigger scopes well though.

 

There are a lot of intangibles with refractors, it's an acquired taste, you will be giving up aperture.  But you also get to observe from a comfortable seated position with the eyepiece facing straight up, every time.  The heaviest component of my 6-inch equatorial is the tube and weighs 27 pounds, the next heaviest part is 20 pounds, which is easier than most mirror boxes, tubes, etc, of larger newts.


Edited by Scott99, 06 August 2014 - 12:13 PM.


#5 Fortress

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Posted 06 August 2014 - 12:32 PM

I guess if I had a permanent observatory are a similar set-up, my opinion would be different.  Since I do not have an observatory, I learned the hard way.  I started out with a 4" apo refractor on an alt-az mount.  I sold it and with a 12.5 Obsession.  The Obsession provided great views, but at a cost.  It was an absolute chore to carry all these components around and set up.  The mirror box was heavy and quite cumbersome.  I did this for less than a year.  I sold the Obsession and, yes, you guessed it, purchased another 4" apo refractor.  For me, even setting up my gem becomes a chore when I only have a few hours to observe.  That's me though.  If you really cannot live without the detail on DSOs you currently enjoy, keep your current set-up and save youself some money.


Edited by Fortress, 06 August 2014 - 12:33 PM.

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#6 WebFoot

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Posted 06 August 2014 - 12:33 PM

I agree with OP completely.

 

That said, there are time when I will choose a small refractor over the 10", for very large objects (think, e.g., open clusters), and for colorful stars (think, e.g., Albireo).

 

Of course, I have a general sense of futility with frequent viewing anyway.  At any particular time, there are no more than a dozen objects in the sky which might be interesting either with the 10" or the small refractors, so, over time, I won't be going out to view very often.  That's why I image.

 

JMO



#7 -Starfighter-

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Posted 06 August 2014 - 01:02 PM

I completely agree about the grab-go ability of the refractor. This is why I picked one up in the first place. However, once you see all the detail that aperture provides, when you take out the smaller refractor the experience is lackluster. It almost leaves me feeling like "Whats that point?" I can appreciate some people like the rich field views, but that seems to me to be the domain of binoculars. When I am looking at the sky I am looking for objects, looking to learn the sky , scanning can be done with a good set of mobile bino's (the real grab-n-go-setup) When I finally have the reward centers firing because I have found a new object, I just want that detail! As I noted previously I think an apo is a must in my future collection, just not the primary scope. I am just feeling like this has been an important realization/evolution in my viewing/setup going forward.


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#8 Astrojensen

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Posted 06 August 2014 - 01:07 PM

 

 

6-inch refractor is probably the smallest one to be considered a serious deep-sky instrument.

 

Oh? Define serious, please. Is Stephen James O'meara not a serious observer, then, because he only uses a 4" refractor? He has used his observations with this instrument as the basis for four observing handbooks. That's pretty darn serious in my book.

 

 

Clear skies!
Thomas, Denmark


Edited by Astrojensen, 06 August 2014 - 01:08 PM.

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#9 Astrojensen

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Posted 06 August 2014 - 01:15 PM

 

 

At any particular time, there are no more than a dozen objects in the sky which might be interesting either with the 10" or the small refractors,

A dozen objects? That's enough for two or three hours of observing. Personally, I find the number staggeringly much higher, even in my 63mm. I can never observe all the objects I want to see, because I run out of energy, it gets too late on a weeknight or it gets cloudy again. 

 

I regard almost *anything* I can see in my 63mm as interesting targets, worthy of at least one good, long look. You never know what you might see, if you try really hard. 

 

 

Clear skies!
Thomas, Denmark



#10 Jon Isaacs

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Posted 06 August 2014 - 01:29 PM

I think there is a place for both refractors and reflectors.. certainly M13 takes on a different character when viewed at 300x in a large scope.. but m13 is still enjoyable in a 4 inch..  there is no perfect scope but two or more well chosen scopes are superior, more capable, than any single scope.

 

I use refractors for low power wide field and easy look-easy setup.. Jupiter in a 4 inch apo..  definitely worthwhile.

 

Jon



#11 WebFoot

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Posted 06 August 2014 - 01:32 PM

 

 

 

At any particular time, there are no more than a dozen objects in the sky which might be interesting either with the 10" or the small refractors,

A dozen objects? That's enough for two or three hours of observing. Personally, I find the number staggeringly much higher, even in my 63mm. I can never observe all the objects I want to see, because I run out of energy, it gets too late on a weeknight or it gets cloudy again. 

 

I regard almost *anything* I can see in my 63mm as interesting targets, worthy of at least one good, long look. You never know what you might see, if you try really hard. 

 

 

Clear skies!
Thomas, Denmark

 

To each his own.  I applaud your ability to be interested in things I am not interested in, but that has no bearing on what interests me.  That's why I image.



#12 Scott99

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Posted 06 August 2014 - 01:34 PM

 

 

 

6-inch refractor is probably the smallest one to be considered a serious deep-sky instrument.

 

Oh? Define serious, please. Is Stephen James O'meara not a serious observer, then, because he only uses a 4" refractor? He has used his observations with this instrument as the basis for four observing handbooks. That's pretty darn serious in my book.

 

 

Thomas - that's funny, I was thinking of Walter Scott Houston and his 4-inch Clark when I wrote that!  yes, of course he was definitely a serious deep-sky observer.  Indeed one can do "serious" work with a 4-inch, it's easily enough to see the Herschel 400 list of objects.  

 

I guess I was referring to my own preference for seeing deep-sky objects.  The 6 inch-apo is enough to keep me observing at my scope & not wandering off to look through various big dobs that are usually on the observing field of my club.

 



#13 Sasa

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Posted 06 August 2014 - 01:54 PM

Starfighter, funny how people are different. I had in past nice tuned 10" f/6.4 Dobson. But once I bought 4" ED scope, the Newton was seeing less and less starlight. I sold it at the end. Dobson was too heavy for short sessions from  my backyard and I was taking it out only in good weather forecast. But with ED and the light alt-az mount, I was out every evening and as a result I saw much more than through the large scope.

 

I know I will never have a refractor that would perform at the same level as this Dobson, but I don't care. I'm quite happy with my largest 110mm refractor sitting in my darker-side observatory.


Edited by Sasa, 07 August 2014 - 04:04 AM.


#14 Max Power

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Posted 06 August 2014 - 02:01 PM

Attached File  GEDC2102.JPG   174.39KB   5 downloadsThat's why man invented wheels, so he won't have to carry heavy loads.  Pictured are 8" dob with wheels for effortless roll-out, and tripod base that is transportable with a 2-wheel handcart, only a little more effort required.  Now if only I can figure out how to rotate pics.....



#15 -Starfighter-

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Posted 06 August 2014 - 02:01 PM

 

 

 

6-inch refractor is probably the smallest one to be considered a serious deep-sky instrument.

 

Oh? Define serious, please. Is Stephen James O'meara not a serious observer, then, because he only uses a 4" refractor? He has used his observations with this instrument as the basis for four observing handbooks. That's pretty darn serious in my book.

 

 

Clear skies!
Thomas, Denmark

 

Galileo's 1620 telescope had and aperture of 36mm. That was serious observing then, hardly a serious instrument now I think you would be hard pressed to find a professional observatory using small commercial telescopes. i would also think universities are using bigger instruments. 4" telescopes are for hobby observing. You don't need to be a serious observer to write a book. I suppose "serious" can mean different things to different people.



#16 Astrojensen

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Posted 06 August 2014 - 02:11 PM

 

 

Galileo's 1620 telescope had and aperture of 36mm. That was serious observing then, hardly a serious instrument now I think you would be hard pressed to find a professional observatory using small commercial telescopes. i would also think universities are using bigger instruments. 4" telescopes are for hobby observing. You don't need to be a serious observer to write a book. I suppose "serious" can mean different things to different people.

EVERYONE in this forum is observing as a hobby, not for a living. Therefore, the idea that a telescope has to be any minimum size to be considered "serious" is flawed. And how can it be considered "serious" to be observing with a 6" refractor, yet it's somehow just a hobby and not serious to use a 4" and write several books about it? 

 

What is a serious observer? I would like to have this defined, even if it's just your own opinion. 

 

 

Clear skies!
Thomas, Denmark

 

PS: There is at least one professional observatory, who uses an array of off-the-shelf Canon camera lenses and CCDs to image gamma ray bursts in visual light. So yeah, some professional observatories do use very small scopes. 


Edited by Astrojensen, 06 August 2014 - 02:19 PM.


#17 Astrojensen

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Posted 06 August 2014 - 02:16 PM

 

 

To each his own.  I applaud your ability to be interested in things I am not interested in, but that has no bearing on what interests me.  That's why I image.

My response was mostly meant to nudge you to explore what's visible with your scope, plus to show that there are observers out there who likes to look at anything they possibly can. I don't like to image, because it robs me of precious eyepiece time. 

 

Each to his own.  :)

 

 

Clear skies!
Thomas, Denmark



#18 areyoukiddingme

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Posted 06 August 2014 - 02:32 PM

I love my little refractors (a 80mm and a 101), but when I get "serious" I need aperture.

 

The ability of O'Meara to find extraordinary detail with his 102 and 127 beggars belief. His eye sight is obviously extraordinary, AND he has some of the best skies on the planet to observe from.

 

In my typical conditions, I've found that my 11" SCT is almost enough to keep up with O'Meara's 4"!



#19 pdxmoon

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Posted 06 August 2014 - 02:41 PM

All of you observers who are too serious to use 60-100mm refractors, please PM me for my address so that you can send them to me--especially those un-serious Unitrons.

 

I'm a completely unserious observer, and having a heck of a good time.  :curtsy:


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#20 -Starfighter-

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Posted 06 August 2014 - 04:50 PM

In all seriousness, my interests have just evolved for the time being, perhaps once I have seen all the objects enough, have the locations and sky all memorized, I will be happy to go back to deep field. 

 

 

 

 

Galileo's 1620 telescope had and aperture of 36mm. That was serious observing then, hardly a serious instrument now I think you would be hard pressed to find a professional observatory using small commercial telescopes. i would also think universities are using bigger instruments. 4" telescopes are for hobby observing. You don't need to be a serious observer to write a book. I suppose "serious" can mean different things to different people.

EVERYONE in this forum is observing as a hobby, not for a living. Therefore, the idea that a telescope has to be any minimum size to be considered "serious" is flawed. And how can it be considered "serious" to be observing with a 6" refractor, yet it's somehow just a hobby and not serious to use a 4" and write several books about it? 

 

What is a serious observer? I would like to have this defined, even if it's just your own opinion. 

 

 

Clear skies!
Thomas, Denmark

 

PS: There is at least one professional observatory, who uses an array of off-the-shelf Canon camera lenses and CCDs to image gamma ray bursts in visual light. So yeah, some professional observatories do use very small scopes. 

 

Well, if you want to get serious..."EVERYONE in this forum is observing as a hobby" would be a generalization because I would not be surprised if there are many professionals (do this for a living) that move about the forums. In addition I would argue that there is definitely a difference between commercial grade and research grade equipment. My note about Galileo is simply conveying the idea that there is a difference between what type of research can be done with larger more complex instruments. I would say that once long ago a 4" quality instrument would be a serious research tool, now I would say the aperture and complexity of the equipment would play a role in what work can be done with it. My point being, that larger telescopes to allow for additional research. A 10" CAT will do everything a 4" refractor will do and more. As aperture increases so does the detail of research. As you previously asked, IMO Serious Observing = Research observing. That being said, amateur observers are finding new things all the time, however this might just be due to the fact that there are many more eyes on the sky and researchers have targeted goals and the equipment to accomplish that goal...in reference to the original quote about the 6" being required to do some serious observing? well I took his comment to mean exactly what I am looking for "serious" detail in DSO's. 

 

You can race an old Ford model T, at one time it may have been relevant to talk about its prowess on the track and so for other models through the years, however if you want to talk about a serious race car today, the engine does mater. 

 

However, this is all tangential to the original topic. I am interested to hear how others have had similar experiences, their opinions, and how they have resolved the issue to satiate their needs.  :lol: 


Edited by -Starfighter-, 06 August 2014 - 04:52 PM.


#21 LewisM

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Posted 06 August 2014 - 05:26 PM

My smallest refractor is an 85mm - Tak FSQ85ED. It punches WELL above it's weight, both visually and photographically. The smallest I have owned is the Tak FS-60CB - a lovely little beast. (well, actually, a Toya/Meade 50mm refractor that I use occasionally as a guidescope counts too I guess)

 

I image nearly exclusively, though do do visual. Nothing beats a GOOD refractor on planets, tight doubles - yes, a GOOD refractor can easily split many difficult doubles - my Vixen FL102S is well capable of doing it, as has been evidenced by a few friend observers, where their Skywatcher's failed to do so.

 

What enamours me more to refractors than anything is the lack of artificially induced imaging artifacts - namely those yak, gad-awful diffraction spikes. I want my images to be as "pure" as possible, and diffraction spikes look like stars from a kid's story book :) ALL the refractors I have have negligable visual and photographic CA, so I don't even include that as an artifact.

 

I have been on the road for righteous telescope discovery for a long while now, and bought and sold a LOT of scopes. I even stupidly sold my Vixen FL102S twice, though bought it back both times. I have had large dobsonians (loathe them), newtonian astrographs (see diffraction spike dislike), Ritchey-Chretiens (PITA) and Cassegrains and Maks (including Mak Newts - The Body Builder's Scope). The ONLY mirror system I ever liked and bought a few times was the Maksutov and the Vixen VC200L - both were visually amazing, and the VC200L, apart again from diffraction spikes, was a fantastic flat field imager.

 

ALL my refractors are collimatable. I have NEVER had to do it, EVER. I cannot say the same about the reflectors I had.

 

To each their own - whatever makes you happy. The little quip in my signature line sums up my thoughts on reflectors :)



#22 cwilson

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Posted 06 August 2014 - 07:27 PM

All of you observers who are too serious to use 60-100mm refractors, please PM me for my address so that you can send them to me--especially those un-serious Unitrons.

 

I'm a completely unserious observer, and having a heck of a good time.  :curtsy:

 

I'll glady take any "overflow" if you get too many! :waytogo:



#23 gene 4181

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Posted 06 August 2014 - 07:57 PM

never mind


Edited by gene 4181, 06 August 2014 - 08:22 PM.


#24 Jon Isaacs

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Posted 06 August 2014 - 08:15 PM

 Nothing beats a GOOD refractor on planets, tight doubles - yes, a GOOD refractor can easily split many difficult doubles - my Vixen FL102S is well capable of doing it, as has been evidenced by a few friend observers, where their Skywatcher's failed to do so.

 

 

Refractors are quite good for their aperture at the planets and at splitting difficult doubles. The difficulty is that few possess sufficient aperture to split very close, very challenging doubles, the Dawes limit on a 4 inch is about 1.15 arc-seconds..  That's idling along for a 10 inch Newtonian.. 

 

Jon


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#25 drollere

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Posted 06 August 2014 - 09:04 PM

this discussion reminds me of the guy who took a hammer back to the hardware store -- wanted his money back, he couldn't turn screws with it.

 

in general, the benefits of aperture work in opposite directions. as aperture increases, resolution increases, but the increased susceptibility of the larger aperture to atmospheric turbulence and cool down problems makes that increase difficult to exploit. at the same time, image brightness increases, and faint objects are easier to see and faint luminance contrasts emerge more clearly, which can be enjoyed at low magnifications where the effects of seeing are minimized.

 

i agree there is a significant difference between a 4" and a 12" aperture, but to get the same relative increase in image brightness you would need to step up to a 36" mirror. many reasons conspire to make ~8"-12" the sweet spot in amateur apertures.

 

to jon's comment ... i'm a double star astronomer first, but i think the benefits of resolution can be overstated. a 1" double is challenging in my 140mm TEC, and a 0.5" is challenging in my 250mm DK. but so what? there are plenty of both classes to be found in the sky, and there is nothing intrinsically more challenging in resolving a binary at the aperture limit in one aperture vs. another: the pleasure is the same. and i can more often exploit that 1" refractor than i can the 0.5" reflector, due to seeing, which is no small compensation.


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