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Cheap small Dob delight

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#1 Binojunky

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Posted 21 June 2018 - 11:35 AM

Well after sitting in my living room corner for several weeks after purchase  I managed to get out last night with an Orion XT6 dob, now this is the basic one, 1.25" focuser, no eyepiece rack and just the one eyepiece, lots of eyepieces already so its not needed anyway. I bought this on a whim new for less than what I have paid for a mid range single eyepiece, $300 Canadian taxes  included, free shipping. I,m older and weight was an issue so the 6" made more sense than the 8" which I owned many years ago so I was aware of the weight and bulk of it, also the 6" will live in a small upright tool shed I have for gardening stuff. Just lift it out and use it.

 Lots of light pollution where I live so I tend to observe the moon and planets so after adjusting the secondary (it was way too far towards the primary) I turned it onto the moon.

 

Well it looks like I got a good one and I came in at 1:30 pm when both it and Jupiter fell behind the trees, tremendous detail on the moon and sharp crisp views, I like a lot of others have over the years got wrapped up in complex and expensive gear so have a night like this for a modest outlay was a delight, I found it really worked well with some of my lower cost eyepieces, higher grade ones made a difference but not that much, waytogo.gif D.

 

 

 


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#2 Astrojensen

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Posted 21 June 2018 - 11:38 AM

A 6" f/8 newtonian with a good mirror is a thing of beauty. 

 

 

Clear skies!
Thomas, Denmark


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#3 petert913

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Posted 21 June 2018 - 12:24 PM

 

A 6" f/8 newtonian with a good mirror is a thing of beauty.

It really is.  Enough aperture and brightness to open the doors to a lot of DSO's.  And good for lunar and planetary.

What's not to like ?

 

Such a classic scope. 


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#4 macdonjh

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Posted 21 June 2018 - 01:09 PM

+1

 

The XT6i was my default recommendation to newcomers who were confident they would enjoy the hobby.  Alas, Orion no longer offers the 6" with IntelliScope.  As Binojunky said, enough aperture to open the door to DSO, can handle magnifications I like to use on planets (200x-300x), light, easily carried, etc., etc.  It's also the perfect size for kids who are old enough to "drive" by themselves.  My son and I used one when he was ten.  He liked that he could collimate it himself, use the IntelliScope computer himself and point the scope himself.  He just wished it tracked.  I almost went to Jon Isaac's house so my son could get a dose of manual tracking bliss.


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#5 Astrojensen

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Posted 21 June 2018 - 01:12 PM

It really is.  Enough aperture and brightness to open the doors to a lot of DSO's.  And good for lunar and planetary.

What's not to like ?

 

Such a classic scope. 

The best thing is that today you can have all this for as little as $300. 

 

 

Clear skies!
Thomas, Denmark


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#6 NEOhio

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Posted 21 June 2018 - 01:28 PM

I have an 8" f/6, which seems to be the more popular size versus the 6" f/8. Are there significant advantages of the 6" f/8 in terms of weight/portability, and/or the longer focal length, that outweigh (no pun intended) the larger 8" aperture? The focal lengths are the same (1200 mm) so the OTA length should be about the same, not sure if the longer f/8 focal length is really noticeable in terms of using low end eyepieces. There is of course the $100 difference between the xt6 and xt8, which is nothing to dismiss :-)  

 

I have never used a 6" f/8 dob, so just curious if there is much practical difference between the two.



#7 macdonjh

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Posted 21 June 2018 - 02:16 PM

I have an 8" f/6, which seems to be the more popular size versus the 6" f/8. Are there significant advantages of the 6" f/8 in terms of weight/portability, and/or the longer focal length, that outweigh (no pun intended) the larger 8" aperture? The focal lengths are the same (1200 mm) so the OTA length should be about the same, not sure if the longer f/8 focal length is really noticeable in terms of using low end eyepieces. There is of course the $100 difference between the xt6 and xt8, which is nothing to dismiss :-)  

 

I have never used a 6" f/8 dob, so just curious if there is much practical difference between the two.

There is a reason that the 8" f/6 scopes are more popular.  The 8" obviously has 2" more aperture, but the focal lengths of the two are the same so the overall sizes of the scopes are similar.  The basic versions are similar in weight, with the 6" being a bit lighter: 34 pounds versus 41 pounds for the 8".  Lower weight and smaller girth compared to the 8" was of benefit for me when I got the XT6i for my son to use with me.  A new XT6 is $100 less expensive (pretty substantial in terms of percentage, 26% less).  In my case, the XT6i was available and the owner was willing to trade straight-up for a William Optics ZenithStar 66mm refractor I didn't use anyway.

 

For beginners wanting to observe DSO, I'm hard pressed to recommend an 8" scope over a 6".  I see a huge jump between 6" and 10", but between 6" and 8", not so much.  However, if a beginner says he (or she) wants to observe the planets, then I see an advantage to an 8" scope.  For me, that's the minimum aperture to get my lazy cones to jump up and take notice so I can see color.  If I observe Jupiter with a 6" scope, I see the Great Tan Spot; with an 8" scope I get to see the Great Red Spot I hear so much about.


Edited by macdonjh, 21 June 2018 - 02:17 PM.

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#8 aatt

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Posted 21 June 2018 - 02:45 PM

A 6" F/8 is likely to have a better mirror than an f/6 8" due to the shallower less exacting parabola with the longer focal length. If you have someone who knows what they are doing, it is easier to make a great optic at that focal ratio.Getting a dog mirror from synta or GSO at that focal length is pretty unlikely while the chance of getting an excellent mirror are pretty high relative to all other apertures. It cools down faster and is easier to collimate. I have a 6" and it is a formidable little scope with a mirror that takes magnification like nobodies business. 50x per inch? Easy. 70x? sure if all things atmospheric agree.It is super easy to move around and under a dark sky it does not disappoint. That being said, I would have bought an 8" back in the day if I could have afforded it. In retrospect, I have no regrets about my purchase. Easily transportable even on family vacations with limited car space is another winning trait.


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#9 mogur

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Posted 21 June 2018 - 03:03 PM

f/6 isn't exactly "exacting". Even coma is almost non-existent at that focal ratio.


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#10 gwlee

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Posted 21 June 2018 - 07:43 PM

I have an 8" f/6, which seems to be the more popular size versus the 6" f/8. Are there significant advantages of the 6" f/8 in terms of weight/portability, and/or the longer focal length, that outweigh (no pun intended) the larger 8" aperture? The focal lengths are the same (1200 mm) so the OTA length should be about the same, not sure if the longer f/8 focal length is really noticeable in terms of using low end eyepieces. There is of course the $100 difference between the xt6 and xt8, which is nothing to dismiss :-)  

 

I have never used a 6" f/8 dob, so just curious if there is much practical difference between the two.

I have owned three of each and still have one of each, both Orion. 6”f8 weighs 34#. 8”f6 weighs 41#. 7# doesn’t sound like much, but it’s a major difference for me at this site that requires a lot of tree dodging; 6” is very easy to use here; 8” is almost unusable, which is why I own the 6. Be aware that 6 and 8 weigh about the same with some brands, SW for example. 

 

Focal lengths are identical, 1,200mm. 6s cools a little faster. All three 6s had a poor a quality 1.25” focuser. It can be adjusted well enough to be serviceable, but requires frequent tuneups. 8s come with an OK 2” focuser. Both are equally easy to colimate to the required tolerances using laser or collimation cap; theory suggests the collimation tolerances are more forgiving on the 6”, but I haven’t noticed a practical difference. 

 

Optical quality (figure) of all of them were about equal, good to very good, no advantage to 6 or 8. 6” might be easier on inexpensive eyepieces, but I only use expensive EP, so can’t say from experience, but it’s consistent with optical theory. 

 

With the same LP EP in both scopes, the 6” has a smaller exit pupil, which is a bit more compatible with the astigmatism in my eyes, so star fields seem a bit sharper to me. At the same exit pupil stars are equal sharp to me in both scopes. I doubt a person without astigmatic eyes would notice a difference. 

 

The larger 8” is a noticeably better optical performer an all targets, but especially DSOs. Noticeable, but not wow! I also believe the 8s have slightly better motions, but it’s subtle, and most people probably won’t notice the difference if they don’t have the opportunity to use bith scopes side-by-side. For sites where I can carry the scope out in two pieces and leave it in one place all night, I prefer the 8. 


Edited by gwlee, 22 June 2018 - 12:42 AM.

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#11 Jon Isaacs

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Posted 21 June 2018 - 09:56 PM

I have an 8" f/6, which seems to be the more popular size versus the 6" f/8. Are there significant advantages of the 6" f/8 in terms of weight/portability, and/or the longer focal length, that outweigh (no pun intended) the larger 8" aperture? The focal lengths are the same (1200 mm) so the OTA length should be about the same, not sure if the longer f/8 focal length is really noticeable in terms of using low end eyepieces. There is of course the $100 difference between the xt6 and xt8, which is nothing to dismiss :-)  

 

I have never used a 6" f/8 dob, so just curious if there is much practical difference between the two.

I have owned more than one 6 inch F/8, more than one 8 inch F/6 and one 10 inch F/5.   The 10 inch F/5 I still have, the others, I couldn't figure out why to use them when I had the 10 inch so they have found new homes.. My two cents:

 

- Weight and portability depend on the individual.  For Binojunky, the lighter weight of the 6 inch F/8 OTA seems to be a real advantage.  For me, that would not be the case.  

 

-  The $100 difference in price is significant but it does buy more than just aperture, generally it means a 2 inch Crayford focuser, if it is GSO Dob, it will be a 2 inch two speed that would cost $130 to buy.  And a decent 50mm RACI finder and a 30mm Widefield eyepiece.  

 

- Some years ago I came up with the phrase:  "The best 6 inch F/8 is an 8 inch F/6."    That pretty much says it all for me.

 

Jon


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#12 barbie

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Posted 21 June 2018 - 10:35 PM

My xt6 is a super planetary scope that does well on deep sky and double stars too.  It has ridiculously sharp optics and is easy to carry and transport.  10 years ago I had an 8"F6 and the quality was not nearly up to the standards of my current 6"F8.  I found it too heavy to use and transport and the mirrors weren't as good as my current 6"F8 so I would say the best 6"F8 is a 6"F8( in dobsonian format, of course).


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#13 gwlee

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Posted 22 June 2018 - 12:17 AM

My xt6 is a super planetary scope that does well on deep sky and double stars too.  It has ridiculously sharp optics and is easy to carry and transport.  10 years ago I had an 8"F6 and the quality was not nearly up to the standards of my current 6"F8.  I found it too heavy to use and transport and the mirrors weren't as good as my current 6"F8 so I would say the best 6"F8 is a 6"F8( in dobsonian format, of course).

 

It’s a fact that the 6” f8 is lighter and less bulky and these facts can be easily proven by objective measurements taken with common household tools. Sharpnes is a bit tougher to measure objectively. It’s easy to compare two scopes that are sitting side-by-side on the same night and make a somewhat objective determination about which is sharper, but much tougher when the comparisons are separated by ten years. At least it is for me because a lot has changed in the last 10 years, my eye sight for example, and also memory fades and becomes less reliable. 

 

For a while, I thought my current 6”f8 was sharper than my current 8”f6, but several weeks of side-by-side testing, some experimentation, and a visit to the eye doc convinced me that the difference I was seeing was very real, but it was due entirely to the larger exit pupil of the 8” scope interacting with the astigmatism in my eyes that had become much worse in the last ten years. When the two scopes were operated the same exit pupil, I could no longer see any difference in sharpness. Also the difference in sharpness largely disaoears when an astigmatism correcting lens (Dioptrx) is installed on the 24mm Panoptic that corrects for the astigmatism in my observing eye. 

 

However, the 6”f8 definitely does provide a sharper star field for my eyes when both scopes have a 24mm Panoptic installed because the 6 produces a 3mm exit pupil that misses the aberration in my observing eye and the 8 produces a larger 4mm exit pupil that passes light through the aberration, but it’s not because the scope is inherently sharper. 

 

Of course none of this means that your current 6” scope isn’t inherently sharper than your previous 8” scope, but it’s something to consider. 


Edited by gwlee, 22 June 2018 - 01:08 AM.

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#14 Jon Isaacs

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Posted 22 June 2018 - 03:18 AM

Of course none of this means that your current 6” scope isn’t inherently sharper than your previous 8” scope, but it’s something to consider

 

Gary:

 

Some nice observations, the exit pupil is an important factor in judging the optical quality of a scope, of the image.  "Sharpness" is a subjective judgment, just what does it mean?

 

I like something more specific, splitting the same close double or showing a particular detail on Jupiter.  In my experience, the 8 inch F/6's I have owned did show more detail, split closer doubles than the 6 inch F/8s.  

 

That said, a good 6 inch F/8 has it's place, it can be the right scope for the individual, for the situation.  That's what this thread is about.  

 

Jon


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#15 starcanoe

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Posted 22 June 2018 - 06:51 AM

f/6 isn't exactly "exacting". Even coma is almost non-existent at that focal ratio.

 

 

Well yes and no.

 

Regarding coma and probably a few other things.  They often go as the square or cube of the f ratio (well 1 over that). So 1 over 8 squared is about half of 1 over 6 squared. The cubed version is even better.

 

Alignment easier in a f8, focusing easier in an f 8, coma "free" field is bigger in an f8. Eyepieces work better at f8 (and often for the more affordable eyepieces there is a BIG difference between operating at f6 vs f8). If the mirror is not carefully figured there is a better chance the f8 mirror has a better wave front than the f6. A six inch mirror will be a bit thinner...and cooling goes as the square too I think.

 

I love the 6 inch f8 dob I use. Small enough for grab and go. Big enough for a fair number of things to be a bit more than "well, I can see it".

 

And IMO a perfect compliment to that is a 3 to 4 inchish achromatic refractor of moderate f ratio (again f8 ish). That covers the WIDE fields you can't quite get with the 6 inch. And since its main purpose is WIDE fields...it being a lowly achromat is fine...no need for an apo here...no worrying about a purple fringe on Jupiter or the moon....because thats what the 6 inch dob is for !

 

I just wish there were commercial 6 inch mirrors of f10 ratio readily available. If my 6 inch was f10 I'd be doing a lot less bending over...I can transport a f10 tube just as easily as f8...and optically and tolerance wise many things would be even better still. An f11 would be workable as well...and at f11 you could just make the mirror a good sphere instead (thats workable at f10 though IMO that is pushing it a bit).


Edited by starcanoe, 22 June 2018 - 06:56 AM.

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#16 macdonjh

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Posted 22 June 2018 - 10:13 AM

I have owned more than one 6 inch F/8, more than one 8 inch F/6 and one 10 inch F/5.   The 10 inch F/5 I still have, the others, I couldn't figure out why to use them when I had the 10 inch so they have found new homes.. My two cents:

 

- Weight and portability depend on the individual.  For Binojunky, the lighter weight of the 6 inch F/8 OTA seems to be a real advantage.  For me, that would not be the case.  

 

-  The $100 difference in price is significant but it does buy more than just aperture, generally it means a 2 inch Crayford focuser, if it is GSO Dob, it will be a 2 inch two speed that would cost $130 to buy.  And a decent 50mm RACI finder and a 30mm Widefield eyepiece.  

 

- Some years ago I came up with the phrase:  "The best 6 inch F/8 is an 8 inch F/6."    That pretty much says it all for me.

 

Jon

Points taken.  We have to keep reminding ourselves in threads that go in this direction: everybody's needs differ, which is why there are so many scopes available.

 

For my son and me: the $100 was important (nobody wanted to trade their 8" f/6 for my little refractor), the bulk and weight mattered to my 10-year-old (wouldn't now, though), the little finder didn't matter because we only used it for the 2-star alignment then never looked through it again, yes, the 1-1/4" plastic focuser supplied with the XT6 is junk.  It is easily modified, though, and works fine once it's fixed.


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#17 Jon Isaacs

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Posted 22 June 2018 - 10:50 AM

Well yes and no.

 

Regarding coma and probably a few other things.  They often go as the square or cube of the f ratio (well 1 over that). So 1 over 8 squared is about half of 1 over 6 squared. The cubed version is even better.

 

 

:waytogo:

 

At F/6, the coma free field is 4.75 mm in diameter , at F/8, its 11.3 mm , about 2.4x greater. In the 6 inch F/8, that's over half a degree. 

 

Collimation is easier,  tolerances are correspondingly more relaxed. 

 

Jon


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#18 Binojunky

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Posted 22 June 2018 - 11:25 AM

Had it out again last night, with the ES 4.7mm eyepiece it gave a mag: of about x255,good views when the air currents settled down, its been hot and I have to observe over house roofs though the moon was up high, I felt it would go a bit higher under better conditions,compared it side by side with a 4"achromat F6.5, the newt won hands down at a similar lower magnification, lots of fine detail, I,m happy, one of the better purchases I have made, is it perfect? no but for the price its a good scope,D.
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#19 barbie

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Posted 22 June 2018 - 01:33 PM

Points taken.  We have to keep reminding ourselves in threads that go in this direction: everybody's needs differ, which is why there are so many scopes available.

 

For my son and me: the $100 was important (nobody wanted to trade their 8" f/6 for my little refractor), the bulk and weight mattered to my 10-year-old (wouldn't now, though), the little finder didn't matter because we only used it for the 2-star alignment then never looked through it again, yes, the 1-1/4" plastic focuser supplied with the XT6 is junk.  It is easily modified, though, and works fine once it's fixed.

The focuser on my XT6 worked just fine right out of the box.  Very smooth and no backlash so I wouldn't say it's junk. It's a heck of a lot smoother than some metal focusers I've used and the build quality is good, despite it being plastic.grin.gif


Edited by barbie, 22 June 2018 - 01:39 PM.

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#20 barbie

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Posted 22 June 2018 - 01:36 PM

It’s a fact that the 6” f8 is lighter and less bulky and these facts can be easily proven by objective measurements taken with common household tools. Sharpnes is a bit tougher to measure objectively. It’s easy to compare two scopes that are sitting side-by-side on the same night and make a somewhat objective determination about which is sharper, but much tougher when the comparisons are separated by ten years. At least it is for me because a lot has changed in the last 10 years, my eye sight for example, and also memory fades and becomes less reliable. 

 

For a while, I thought my current 6”f8 was sharper than my current 8”f6, but several weeks of side-by-side testing, some experimentation, and a visit to the eye doc convinced me that the difference I was seeing was very real, but it was due entirely to the larger exit pupil of the 8” scope interacting with the astigmatism in my eyes that had become much worse in the last ten years. When the two scopes were operated the same exit pupil, I could no longer see any difference in sharpness. Also the difference in sharpness largely disaoears when an astigmatism correcting lens (Dioptrx) is installed on the 24mm Panoptic that corrects for the astigmatism in my observing eye. 

 

However, the 6”f8 definitely does provide a sharper star field for my eyes when both scopes have a 24mm Panoptic installed because the 6 produces a 3mm exit pupil that misses the aberration in my observing eye and the 8 produces a larger 4mm exit pupil that passes light through the aberration, but it’s not because the scope is inherently sharper. 

 

Of course none of this means that your current 6” scope isn’t inherently sharper than your previous 8” scope, but it’s something to consider. 

My 6"F8 is inherently sharper than my former 8"F6 and no, I don't have astigmatism.lol.gif


Edited by barbie, 22 June 2018 - 01:41 PM.


#21 gwlee

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Posted 23 June 2018 - 01:20 PM

Gary:

 

Some nice observations, the exit pupil is an important factor in judging the optical quality of a scope, of the image.  "Sharpness" is a subjective judgment, just what does it mean?

 

I like something more specific, splitting the same close double or showing a particular detail on Jupiter.  In my experience, the 8 inch F/6's I have owned did show more detail, split closer doubles than the 6 inch F/8s.  

 

That said, a good 6 inch F/8 has it's place, it can be the right scope for the individual, for the situation.  That's what this thread is about.  

 

Jon

Like pornography, I find sharpness is difficult to define, but easy to recognize. I am probably using the term imprecisely, but here's an example of how I think of it. When my scope is unfocused, the image is blurry, contrast is low, and I can see few details. When I adjust the focuser to the point were contrast is the highest and the most detail shows in the image, the image is no longer blurry, it's "sharp." We could get into MTFs and such, but I think most layman understand what I am describing and will agree that sharpness is a desirable property in a telescope, and that some telescopes are sharper than others.

 

However, sharpness a difficult property to measure objectively in the field, and the best I can do is to use both scopes in the field side-by-side over a long period of time, preferably one or two years, assuming that both scopes are of good quality and functioning properly.  I consider single-scopes tests a better test of "seeing" tests than a scope test, and don't have much confidence in critical comparisons that aren't done side-by-side. 

 

A properly functioning big telescope will usually split tighter doubles than a properly functioning small telescope because it has greater inherent resolution. If it can't there's usually something wrong with it, so the biggest scope will almost always be the "sharpest" telescope using this test.

 

Comparing two scopes of identical size on doubles can show which is sharper, but doubles are not convenient targets for comparing two hand driven, alt/az scopes side-by-side at high power, and doubles aren't that interesting to me. I don't see much detail on Jupiter, so don't use it much for these comparisons. 

 

Instead, I like to look at star fields, and I want to see every star as a pin point right to the edge. For this task, I have never found anything better than an NP101. I would call this a very "sharp" scope, but it was one of the smallest scopes I have owned and not as good at splitting tight doubles as the three 6-8" newts that I owned at the time. I also like viewing lunar detail to compare medium to high power views.

 

Using star fields, I find my 6"f8 a little sharper than the 8"f6 at low power. Primarily because it's smaller exit pupil at the same magnification is a little easier on my astigmatic eyes, and secondly it has a touch less coma at the field edge, but neither scope seems to have an overall sharpness advantage on a wide variety of targets. 

 

Scope selection is very much a personal matter. I want the scope that's best suited to my observing interests, my observing style, and my observing site, not necessarily the "best" scope. I also usually prefer to own just one scope and use it for everything. With that goal in mind, it's usually a 6-8 Dob, depending on the site, but I a tie usually goes to the 6"f8, and one day I hope to own a premium version that lives up to the scopes full potential. 



#22 Jon Isaacs

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Posted 23 June 2018 - 02:05 PM

Instead, I like to look at star fields, and I want to see every star as a pin point right to the edge. For this task, I have never found anything better than an NP101.

 

 

I've owned my NP-101 for 8 years.  I call that,  "sharp across the field" but only consider that one aspect and one that's very dependent on the eyepiece.  The NP-101 is very tough on eyepieces because it's quite fast and with that flat field , imperfections are easily seen.  The NP-101 with the 30 mm GSO Superview is not sharp across the field.  It takes eyepieces like the 31 mm Nagler to provide that sharp-sharp field of view .

 

In comparing a 6 inch F/8 to an 8 inch F/6, the F/8 would exhibit much less coma so those low power wide field views would sharper to the edge .  Unless a coma corrector were used .

 

I think of sharpness as a quality that manifests itself a high magnifications ... a sharp scope has excellent optics and provides crisp views of the planets and well resolved views ofof doubles.  It can be a relative measure.. 

 

Jon


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#23 gwlee

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Posted 23 June 2018 - 04:02 PM

I've owned my NP-101 for 8 years.  I call that,  "sharp across the field" but only consider that one aspect and one that's very dependent on the eyepiece.  The NP-101 is very tough on eyepieces because it's quite fast and with that flat field , imperfections are easily seen.  The NP-101 with the 30 mm GSO Superview is not sharp across the field.  It takes eyepieces like the 31 mm Nagler to provide that sharp-sharp field of view .

 

In comparing a 6 inch F/8 to an 8 inch F/6, the F/8 would exhibit much less coma so those low power wide field views would sharper to the edge .  Unless a coma corrector were used .

 

I think of sharpness as a quality that manifests itself a high magnifications ... a sharp scope has excellent optics and provides crisp views of the planets and well resolved views ofof doubles.  It can be a relative measure.. 

 

Jon

I generally agree with you, but consider sharpness at high power only one test or aspect of sharpness and sharpness across the field another. If high power was my primary type of viewing, that might be my primary method of testing sharpness, but I prefer a scope that gives me a good balance of both. 

 

I found the NP101 very sharp across the field with Panoptics and Nagler T6s and very sharp at high power until it was compared with larger scopes that had much more resolution. “Very” meaning relative to the 1/2 dozen scopes that I owned at the time.

 

Unfortunately, unlike weight or size, few of us have the test equipment required to get an absolute measurement of sharpness, so relative comparisons must do, but long duration, side-by-side testing is somewhat more objective.

 

I really wish I had kept the NP101 for a second scope now, but it wouldn’t do everything I required of a one-scope solution so it went to a good home after a couple of years. I realize that one scope can’t do everything, but I don’t want to do everything, so I can usually find a satisfactory one-scope solution with enough time and effort. 

 

I know you have done a lot of observing at high power. Most of the observing sites that I have used regularly have poor seeing, and haven’t lent themselves to high power observation. I spent a couple of years testing two 8”f6 scopes, one with Zambuto optics, the other Synta optics.  Eventually, I accumulated enough side-by-side time in good seeing on these two scopes to unequivocally confirm that the Zambuto had the sharper views at high power.

 

Since retiring and moving to a new home a few years ago, I have been intensively evaluating two 6”f8 and one 8”f6 Dob to see, which works best for me at this site and feel that I have a good handle on what each does best, but haven’t decided which to keep. 


Edited by gwlee, 23 June 2018 - 05:47 PM.


#24 Binojunky

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Posted 26 June 2018 - 09:58 AM

The focuser on my XT6 worked just fine right out of the box.  Very smooth and no backlash so I wouldn't say it's junk. It's a heck of a lot smoother than some metal focusers I've used and the build quality is good, despite it being plastic.grin.gif

Same here, plastic but its fine for my needs which are visual, replace? maybe a wintertime project but its not screaming at me to do this,D.



#25 gwlee

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Posted 26 June 2018 - 01:56 PM

Same here, plastic but its fine for my needs which are visual, replace? maybe a wintertime project but its not screaming at me to do this,D.

Let us know if you find a good replacement for the stock focuser. I have been looking for a good drop in replacement for mine, but haven't found one yet. 




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