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Comparison of NexStar SE Scopes

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#1 chemist

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Posted 09 February 2013 - 06:32 PM

With some trepidation, I thought I would explore the “technical” differences between the NexStar SE telescopes. Let me begin by stating that all of these instruments are well made, easy to use and can provide a lifetime of enjoyment under the stars. Also, I will not address the 4SE since it’s a Mak rather that an SCT.

Here’s a compilation of stats that I have assembled from a variety of internet sources:

Model………......5SE……….......6SE………....8SE

Aperture……....125mm……....150mm…....200mm

Resolution…...1.12 arc”…...0.93 arc”…..0.70 arc”

Focal………......1250mm…....1500mm…...2032mm
Length

Limiting Magnitude
City………….......8.7.………....9.1.………...9.7
Suburban……...10.2.………...10.6.………..11.2
Dark Site……...12.7.………...13.1.………..13.7

Cost………….....$700.……....$800.……...$1200

So what do I take away from this comparison? First, the 6SE offers a little more resolution and light gathering capability (not to mention a more substantial mount and tripod) than the 5SE for just a little more money ($100). Second, the 8SE offers a little more resolution and light gathering capability than the 6SE for a lot more money ($400). Is the 8SE worth 50% more than the 6SE? Perhaps, if you plan to use the scope at or near its limits. But for average viewing on an average night the 6SE is a great value.

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#2 mitaccio

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Posted 09 February 2013 - 06:53 PM

Having had both the 6 and 8 inch models, I can firmly attest to the improvement in light gathering power of the 8. For my eyes, there was a great deal more light being brought in and was worth every penny of the upgrade. Numbers don't show you images. Eyes do that.

#3 RTLR 12

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Posted 09 February 2013 - 07:20 PM

The numbers thing is great, but sometimes you have to get out of the library to do a real comparison.

Stan

#4 Midnight Dan

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Posted 09 February 2013 - 08:18 PM

Hi Chemist:

If you do the calculations, and include the effect of the central obstruction, you'll find:

Comparing the 6 to the 5:

43% more light gathering
20% more resolution
18% more contrast

Comparing the 8 to the 6
91% more light gathering
35% more resolution
48% more contrast

The leap from the 6 to the 8 is MUCH larger than the leap from the 5 to the 6, especially in light gathering which is almost double.

Something that's left out of your numbers is size and weight. One of the reasons I chose the 5 over the 6 for a travel scope is that the mount head is smaller and weighs less. The 6 and 8 share the same mount, but the 4/5 mount is a smaller version. Still holds the 5 VERY solidly, but is more compact for a travel situation.

-Dan

#5 Peter9

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Posted 10 February 2013 - 04:17 AM

Having had both the 6 and 8 inch models, I can firmly attest to the improvement in light gathering power of the 8. For my eyes, there was a great deal more light being brought in and was worth every penny of the upgrade. Numbers don't show you images. Eyes do that.


Agreed. I have upgraded from the 6se to the 8se and can testify to a marked difference at the eyepiece. Numbers are O.K ...but.

Regards. Peter.

#6 sonny.barile

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Posted 10 February 2013 - 10:21 AM

There is a huge difference. In fact, I once owned an 8" Coulter Dob and there is a huge difference in optical quality in comparison to that. The 8se is more expensive than the smaller versions for obvious reasons, but none of that matters. I firmly believe in the old adage "The scope you use has a larger aperture, higher definition, and better contrast" than the one you dont own or are not using.

Regards
Sonny

#7 chemist

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Posted 10 February 2013 - 07:01 PM

OK, I didn't intend to enrage all of the 8SE owners out there. I was just pointing out that it's OK to own a 6SE instead and that it's price/performance is a very good value.

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#8 Midnight Dan

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Posted 10 February 2013 - 07:08 PM

Absolutely! I don't think anyone was enraged. Just sharing their opinions! :grin:

-Dan

#9 hopskipson

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Posted 10 February 2013 - 08:44 PM

Not enraged either! I like Sonny's reasoning. The best scope is the one you are looking through. If the 8se is too heavy to handle you are less likely to set it up and therefore an expensive dust collector.

#10 ben2112

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Posted 10 February 2013 - 09:10 PM

+1 on Sonny's reasoning. But I don't think weight should be a factor, as the mount is the majority of the weight. Also, the 6SE and 8SE use the same mount. When I got my 8SE, I was more afraid of the bulk of the OTA more then anything. But the more I handled it, the more I got used to it. It might not be as portable as a 4SE or a 5SE, but it is still pretty portable to me. Just my 2 cents.

I would rather see a person buy a 4SE and use it then for them to buy a 8SE and for it to collect dust.

#11 mitaccio

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Posted 10 February 2013 - 09:31 PM

Also not upset at all. I loved my 6SE. It was my favorite scope until I traded it for my 8SE. Now I love my 8. My favorite is the one I own. The 8 is "somewhat" harder to transport than the 6SE, but I am 32 years old and 6'1". So it isn't that big to me. One day it won't be a grab-n-go. Hopefully I have an observatory then.

You won't be disappointed with a 6SE. But the 8SE if you can afford it will show you more.

#12 Peter9

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Posted 11 February 2013 - 07:20 AM

I don't think people who have had, or still have, both scopes, should be labled "enraged" for passing on their "hands on" experiences with both scopes. Similarly, nor should those correcting the statement

"The 8SE offers a little more resolution and light gathering capability than the 6SE".

That said, your praise for the 6se is justified and welcome. It is indeed a great scope in its own right and a match for any scope in its range.

Regards. Peter.

#13 Gary Z

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Posted 18 February 2013 - 06:22 PM

I think it is great that we share the discussions and logic behind each choice...we all shared these thoughts on size/performance/value before purchasing our scopes. Makes for interesting reading!

#14 hopskipson

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Posted 19 February 2013 - 01:13 PM

I know this is a tad off topic, but has anyone compared the difference between the C8, C9.25 and C11?

#15 ghataa

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Posted 20 February 2013 - 10:11 AM

Lol, not bothered at all! I see value in all scopes and the more the merrier!

Best,

George

#16 careysub

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Posted 02 March 2013 - 10:20 AM

One other significant parameter left off is the TFOV of the scopes, which are limited by the baffle tube. It is a bit hard to get comparative numbers for them all though.

According to Swanson's "The NexStar User's Guide" the TFOV (deg) are:
-----Stock----With Reducer
C5----1.75-------2.2
C8----1.0--------1.3
C11---1.0--------1.0

Others have reported:
C6----1.3--------??

#17 butsam

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Posted 02 March 2013 - 03:50 PM

I got my 8SE with all sorts of accessories (EP/filter kit, power tank, vibration suppression pads) for under $1300, so even though retail it appears like a large price difference, you can certainly find it cheaper.

Also, I am not sure what the dark sky limiting magnitude is that you quote. You either need to add a line, or change those numbers. The limiting magnitude for the 8SE is over 14. (I think it is about 14.5?)

Finally, it might be helpful if you "de-logarithmize" the scale (yes, I just made that word up). I heard somewhere that, for every increase in number, that represents about 3.2x the light-gathering capacity. As a rough hack (not completely correct -- you should actually truly exponentiate), a difference in Suburbia (where I am) of 0.6 is something like almost 80% more light...for everything. That means things barely visible in a 6" at 10.5 mag in suburbia will be fairly easily visible in the same suburbia setting with an 8".

Also, I realize the definition of "suburban" is variable, but I live in a suburb of a reasonable-sized city (Dayton, OH) and in the past, I have seen stars labeled as mag. 12 with my 8 SE (although I don't recall what the sky conditions were...it was my 2nd time using the 'scope, I was just happy it was clear out!) I wasn't even trying to look at dimmer objects this past Monday, but I easily saw something Stellarium said was mag 11.4 next to an object I was looking at, without even putting any effort into it. The skies were what cleardarksky.com called poor transparency (2/5) and poor seeing (2/5).

All that said, I laud your efforts to put down numbers to help people decide. I am just saying that, at a minimum, the numbers for the 8SE seem conservative to me...which may also mean the numbers for the 6SE and/or 5SE are conservative, but I can't comment on that.

I think it is good you point out the 6SE gives you not just a bigger bucket, but also a sturdier mount. This opens up the option for the 8SE by just upgrading the tube later, or stick with the 6SE, which is an excellent choice as well.

All this said, I think any of them are great 'scopes!

#18 Midnight Dan

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Posted 02 March 2013 - 04:03 PM

One other significant parameter left off is the TFOV of the scopes, which are limited by the baffle tube. It is a bit hard to get comparative numbers for them all though.

According to Swanson's "The NexStar User's Guide" the TFOV (deg) are:
-----Stock----With Reducer
C5----1.75-------2.2
C8----1.0--------1.3
C11---1.0--------1.0

Others have reported:
C6----1.3--------??


These numbers seem about right for the unvignetted field of view. In other words, the brightness of the view will be pretty even across a field of that size. However, you can go quite a bit larger before you hit a hard edge to the field, but the view does get a bit dimmer the farther out you go.

I have measure the maximum field of view of my C8 at just under 2° with a focal reducer and a 36mm, 72° AFOV eyepiece. With that configuration, I can see a slight sliver of black around the edge of the view, indicating that the field of view is slightly smaller than what the eyepiece/reducer combination would otherwise allow. I then measure the angular field from edge to edge of that view.

-Dan






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