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Nexstar 8 or 8SE?

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#1 dogeddie

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Posted 13 January 2013 - 12:02 AM

Hi, what is the difference between a Nexstar 8 and a Nexstar 8SE? Thanks

#2 Tel

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Posted 13 January 2013 - 04:28 AM

Hi Dogeddie,

All 'scopes within this series, (i.e. from the original Nexstar 8 to the current Nexstar 8SE), share the same optical system with an aperture of 203mm and a focal length of 2032mm, (f/10). The transmission coatings have however changed over the years from those called "Starbright" on the earlier Nexstar 8 and 8i models, to "XLT" coatings on the later, (short lived) Nexstar 8iSE and the current Nexstar 8SE.

Secondly, the Nexstar 8, the 8i and the 8iSE were "fixed" to the single arm of the mount: i.e. no "slideability" was provided as it is today on the Nexstar 8SE via its Vixen dovetailed rail.

This was a distinct disadvantage in those earlier models as it precluded access to the Zenith with any additional piece of equipment, (such as a focal reducer or a motorised focuser), which would bulk against the base of the mount should the OTA be elevated much above ca.80 degrees.

To overcome this problem, two American guys, Ray Cooper and Frank Dilatush (Sp?) invented what is known as "Ray's Bracket" which substitutes this OTA fixture for a slideable system, specifically aimed at the time at the Nexstar 5/8 and Nexstar 8/8i markets. (I believe they are still available today).

Going back to the Nexstar 8, apparently the motorised drive lacked accuracy over prolonged periods, an aspect which was to be corrected in the Nexstar 8i's mount via new electronics.

By similar token, the Nexstar 8i's mount was to receive two in-built ports on its base: one, an auxillary port: the other, an auto guide port: the former being able to accept, for example, the likes of a GPS system, (Celestron marketed such under the brand N16), or if preferred, the 'scope's hand controller could be plugged in at this point as an alternative the mount arm. The auto port was supposedly for guiding the 'scope when carrying out long exposure imaging but in all truth, the mount is incapable of allowing such even if sitting on a wedge due to its relatively excessive backlash inherent spur gear drive compared to that of worm gear drive.

Finally, hand controller firmware has of course been vastly upgraded over the years. However, neither the hand controller supplied with the Nexstar 8 nor that of the Nexstar 8i were flash upgradeable in themselves. A new modern hand controller could be purchased to upgrade the original supplied with the Nexstar 8i, but not so that of the Nexstar 8, which remains the case. Thus the Nexstar 8 can only be used with the originally supplied hand controller.

I hope this at least gives you somewhat of an overview as to the differences between these various Nexstar models. If I have missed anything then please forgive me. No doubt our colleagues here on this CN forum will advise you further.

Best regards,
Tel

#3 dogeddie

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Posted 13 January 2013 - 08:44 AM

Thanks for the detailed response. What should one pay for a used plain ol' 8(non SE)
these days?

#4 Midnight Dan

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Posted 13 January 2013 - 09:46 AM

Another thing to consider regarding an older model like the 8 is mirror oxidation. Over time, any scope with a mirror will experience oxidation on the mirror surface which reduces reflectivity. The amount of oxidation can vary greatly depending on temperature swings, humidity, mirror cleanliness, etc. I've heard some say you should re-coat mirrors every 10 years or so, but most use scopes without noticeable degradation for much longer than that.

In any case, it's just something to keep in mind. While I doubt the 8 has enough oxidation to make any difference yet, the fact that it is probably in the vicinity of 10 years old means it is at least starting down that oxidation curve and has less life in it than a newer scope.

I have owned a plain old 8 in the past and upgraded to the 8SE. I liked the idea of the newer firmware and upgradable handset, and the 8SE's dovetail mount which allowed adjusting the position of the scope for balance or clearance. As Tel says, you can get a Ray's bracket for the 8, but that's added cost. I also noticed a distinct improvement in the views when moving to the 8SE, but that may have just been luck-of-the-draw with my two particular examples. There is always some scope-to-scope variance within any model of SCT.

One more thing that a new 8SE gets you is a 2-year warranty. Definitely worth something in the purchase price. Personally, I wouldn't pay more than $500 for an 8. But I'm not sure what they're getting for them on the used market.

-Dan

#5 azure1961p

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Posted 13 January 2013 - 09:55 AM

Tel,

Thanks for the clarification. I recall over the phone when I made my purchase I inquired to the meaning of the SE following the Nexstar6 and the fella laughed and said he had no idea "maybe it stands for special edition?".

Again thanks for clarifying.

Pete

#6 Tel

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Posted 13 January 2013 - 11:47 AM

Hi Pete,

Well, in fact he was quite right. :waytogo:

At least this "tag" was appended to the Nexstar 8i SE (the first of the "orange tubes") and therefore, I assunme it persists ! :lol:

www.nexstarsite.com/Book/Updates/N8iSE.htm

Best regards,
Tel

#7 Arthur Dent

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Posted 13 January 2013 - 02:22 PM

Yep that's quite right.

The 4, 5, 6 and 8SE have been around for so long, maybe it should now mean Standard Edition

Art :grin:

#8 BigC

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Posted 14 January 2013 - 11:34 AM

I'm not upgrading my 5i and losing the GPS align!

Looked for an 8i for a couple years but ebay bidder pushed them past what I could get a nice 8SE (used).

Not sure if *iSE is really an improvement over the standard 8i.

Celestron move to dovetaikl mounts and better accuracy in the 6/8SE is definitely a step up.

#9 Greyhaven

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Posted 14 January 2013 - 12:06 PM

Tel
The Ray's Bracket is still available at least for the 5i. I've had clearance problems with AP with interference with the battery case so I ordered one Sunday afternoon and received confirmation that it was shipped today,Monday.
I'm wondering if for $30. I should order a rail that would make it possible to use my 90mm on the same mount, without balance issues. But, that's for another post in another forum far, far away.
Be Well
Grey

#10 Tel

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Posted 14 January 2013 - 01:51 PM

Hi Grey,

That is fact what I did.

Back around 2007/2008, (as far as I can remember), I had a second plate made up which slots into the half of my "Ray's Bracket" which is fixed to my Nexstar 8i's mount. It, in turn, has a dovetail shoe attached to it which can receive the dovetail rail attached to my 102mm f/5.9 refractor.

As to balance or lack of it, yes, the refractor was somewhat nose heavy, particularly when positioned to allow access to the Zenith.

To overcome this, (and some may regard this as the cardinal sin), I tightened the clutch adjustment to cope with this imbalance and thus overcame any tendency for the OTA to drop under its own weight. I would add that I never had any problem with this set up whatsoever !

Perhaps the attached image provides some idea ? I have to say though, that I very rarely use my original Nexstar 8i's mount for any purpose nowadays, as my two 'scopes; (the 102mm refractor and the N8i, now reside side by side on a tandem bar on a GEM in my observatory).

Best regards,
Tel

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#11 Tel

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Posted 14 January 2013 - 01:53 PM

And perhaps ?

Best regards,
Tel

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#12 Bob Griffiths

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Posted 14 January 2013 - 02:02 PM

I'm not upgrading my 5i and losing the GPS align!

Looked for an 8i for a couple years but ebay bidder pushed them past what I could get a nice 8SE (used).

Not sure if *iSE is really an improvement over the standard 8i.

Celestron move to dovetaikl mounts and better accuracy in the 6/8SE is definitely a step up.


LOL... I coud care less about the GPS .. I did upgrade my 8i shortly after I purchased it because at the time I traveled during the work week and often found myself setting up a few hundred miles away from where I had set up the night before.. The GPS simply solved the problem of finding out where the heck I was...
Anyway I did miss the GPS alignment procedure on the 8i (it used North and Level) when I upgraded to a SkyAlign HC...yep missed it for all of about 5 minutes.. I paid serious money (for the CN-16 lol) so you bet I still use the GPS with the scope but only to enter the date and time..

The *iSe was just a "special Edition" because it brought back the orange colored OTA which was similar but not the same color ORANGE.. Mechanically and optically they were identical to the 8i ..The last few months that they were sold the Coatings were available as Starbright XLT coatngs...

I'd personally pay $500 for a good 8i BUT not a cent more then $250 for an original 8

BTW... I also think my 8i with the addition of a SkyAlign Hand controller and rays brackets is better then an 8Se LOL...Actually purchased an 8Se for my granddaughter rather then give her my 8i as I had promised her after I pulled the 8i out of my observatory and replaced it with a CPC1100 ..

I just could not part with an old friend (the 8i)

Bob G.

#13 Greyhaven

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Posted 14 January 2013 - 02:09 PM

Tel
Thanks for that second shot ( and 1st one too). I would imagine that a stout length of red oak dovetailed to match and the original mounting rings would be as sturdy and allow me better control of the length of the
rail for balancing the rig. I love the smell of sawdust in the morning.
As always, thanks for the advice.
Be Well
Grey

#14 BigC

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Posted 14 January 2013 - 02:28 PM

Spending $150 for a new Hand Controller rather changes the cost factors.

Add another ,what, $110 for Ray's Rails (which are fine products) ,

and you might as well put that money towards a newer scope.

By the way,ebay buyers seem to be paying about $500 for the original N8.

#15 Tel

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Posted 14 January 2013 - 02:54 PM

Hi BigC,

If Dogeddie were to decide to "go" for a Nexstar 8, there is no question of having to pay out ca. $150 for a modern hand controller because, as stated above, unlike the Nexstar 8i and all models thereafter, the Nexstar 8 hand controller is just not upgradeable or replaceable with a later version; (i.e. only the original hand controller is compatible with the Nexstar 8).

On the other hand though, while a Ray's Bracket is not an absolute necessity, it is a highly desireable accessory which opens up a whole new dimension for this otherwise "fixed to the arm" 'scope.

Best regards,
Tel

#16 BigC

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Posted 15 January 2013 - 12:52 PM

I had thought only that the original handset was not upgradeable;didn't realize the the base could not accept a newer handset.That could be a problem when one's original handset fails!

#17 Tel

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Posted 16 January 2013 - 04:42 AM

Absolutely ! :praying:

Best regards,
Tel






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