I currently have a Meade 12.5" Dobson. After a few (ok, a lot) of modifications, I love my telescope except for the fact that I have to decide between it or the kids if I'm going somewhere. It's just too large. So, I'm considering another telescope and I'm hoping I can get some opinions on what I'm considering from the wise and learned folks on this list. I've decided that an 8" Schmidt-Cassegrain is just the ticket and I think I've narrowed it down to these two models which are in my price range and appear to have all the features I want: Option #1: Celestron Nexstar 8i Product Information: http://www.celestron.com/prod_pgs/tel/nx8ise.htm Option #2: Celestron C8-SGT Product Information: http://www.celestron.com/prod_pgs/tel/c8sgt.htm The second telescope is about $100 more than the first. From my searches on the Internet, they both get decent reviews. Does anyone know what the practical differences are between these two scopes? Does anyone know of any issues with Celestron's quality? Are there any other brands/models you would recommend? Thanks in advance for any advice or help you can offer. -- --Chris Russell
On Mar 22, 2006, at 10:00 PM, Chris Russell wrote:
I love my telescope except for the fact that I have to decide between it or the kids if I'm going somewhere. Sounds perfect just the way it is.
But if you must change, I'd recommend the SGT version of the scope. As a German equatorial, It might take a few extra minutes to align. But it will be considerably more stable. I have the first generation of Nexstar 8". I understand they've improved it considerably, but my experience tells me that still isn't enough. The single fork arm just doesn't have enough mechanical stability and high magnification views are seriously compromised because of periodic error and damping problems. From what I hear, the CG5 mount in the SGT version has been beefed up, and while not observatory class, it can still hold the 8" nicely. By the way, my criticism of the Nexstar only applies to the mount. The OTA is very nice. Someday when both time and money allow, I'll mount it appropriately. I'm sure you're already aware of this, but the views you get with an 8" SCT will be considerably different from a 12.5" Dob. In addition to the full magnitude difference in light-gathering, your field of view will change a lot. Planetary and lunar views are superb with an SCT (refractor purists will disagree, but they've got to justify dropping $3,000 for 4 inches of aperture). Other views that you've grown used to (let's say M51) will lose considerable detail. One last thing. If you pop for either of the scopes, be sure to spend an extra $15 on a set of Bob's Knobs. These are little thumbscrews that replace the collimating screws on the scope. Depending of Celestron's mood, they give you either phillips head or hex head collimating screws. To collimate, you have to stand in front of the scope, just hoping you don't scratch your corrector. And you've got to keep track of the tool. With Bob's knobs, you can easily reach the adjusters while at the eyepiece. Collimation changes from a chore to a piece of cake. Hope this is helpful, Michael
I've decided that an 8" Schmidt-Cassegrain is just the ticket and I think I've narrowed it down to these two models which are in my price range and appear to have all the features I want:
Option #1: Celestron Nexstar 8i Product Information: http://www.celestron.com/prod_pgs/tel/nx8ise.htm
Option #2: Celestron C8-SGT Product Information: http://www.celestron.com/prod_pgs/tel/c8sgt.htm
Amen to what Michael has said. The main advantage of the first telescope is that it is a fork and you can view objects in the north more readily but the stability issue goes with the German equatorial. The same mount holds much larger telescopes (see Celestron's website) so it should be stable for an 8". I have the mount the CG-5 was based on, the Vixen GP-DX, and it holds an 8" very well and a 9.25" well enough to due planetary imaging. Clear Skies Don -----Original Message----- From: utah-astronomy-bounces+djcolton=piol.com@mailman.xmission.com [mailto:utah-astronomy-bounces+djcolton=piol.com@mailman.xmission.com] On Behalf Of Michael Carnes Sent: Thursday, March 23, 2006 6:23 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] Trying to decide between two telescopes On Mar 22, 2006, at 10:00 PM, Chris Russell wrote:
I love my telescope except for the fact that I have to decide between it or the kids if I'm going somewhere. Sounds perfect just the way it is.
But if you must change, I'd recommend the SGT version of the scope. As a German equatorial, It might take a few extra minutes to align. But it will be considerably more stable. I have the first generation of Nexstar 8". I understand they've improved it considerably, but my experience tells me that still isn't enough. The single fork arm just doesn't have enough mechanical stability and high magnification views are seriously compromised because of periodic error and damping problems. From what I hear, the CG5 mount in the SGT version has been beefed up, and while not observatory class, it can still hold the 8" nicely. By the way, my criticism of the Nexstar only applies to the mount. The OTA is very nice. Someday when both time and money allow, I'll mount it appropriately. I'm sure you're already aware of this, but the views you get with an 8" SCT will be considerably different from a 12.5" Dob. In addition to the full magnitude difference in light-gathering, your field of view will change a lot. Planetary and lunar views are superb with an SCT (refractor purists will disagree, but they've got to justify dropping $3,000 for 4 inches of aperture). Other views that you've grown used to (let's say M51) will lose considerable detail. One last thing. If you pop for either of the scopes, be sure to spend an extra $15 on a set of Bob's Knobs. These are little thumbscrews that replace the collimating screws on the scope. Depending of Celestron's mood, they give you either phillips head or hex head collimating screws. To collimate, you have to stand in front of the scope, just hoping you don't scratch your corrector. And you've got to keep track of the tool. With Bob's knobs, you can easily reach the adjusters while at the eyepiece. Collimation changes from a chore to a piece of cake. Hope this is helpful, Michael
I've decided that an 8" Schmidt-Cassegrain is just the ticket and I think I've narrowed it down to these two models which are in my price range and appear to have all the features I want:
Option #1: Celestron Nexstar 8i Product Information: http://www.celestron.com/prod_pgs/tel/nx8ise.htm
Option #2: Celestron C8-SGT Product Information: http://www.celestron.com/prod_pgs/tel/c8sgt.htm
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Michael Carnes wrote:
But if you must change, I'd recommend the SGT version of the scope. As a German equatorial, It might take a few extra minutes to align. But it will be considerably more stable. I have the first generation of Nexstar 8". I understand they've improved it considerably, but my experience tells me that still isn't enough. The single fork arm just doesn't have enough mechanical stability and high magnification views are seriously compromised because of periodic error and damping problems. From what I hear, the CG5 mount in the SGT version has been beefed up, and while not observatory class, it can still hold the 8" nicely. By the way, my criticism of the Nexstar only applies to the mount. The OTA is very nice. Someday when both time and money allow, I'll mount it appropriately.
I was wondering if the single fork could really be all that steady, so I appreciate your feedback. I understand it's easier to use and set up, but I would definitely prefer something more steady.
I'm sure you're already aware of this, but the views you get with an 8" SCT will be considerably different from a 12.5" Dob. In addition to the full magnitude difference in light-gathering, your field of view will change a lot. Planetary and lunar views are superb with an SCT (refractor purists will disagree, but they've got to justify dropping $3,000 for 4 inches of aperture). Other views that you've grown used to (let's say M51) will lose considerable detail.
Yes, I realize this probably wouldn't replace my other telescope if I wanted the best view. I would just like to get something that would work well as a pinch hitter if I'm taking my kids along while traveling somewhere (such as camping or visiting relatives in Southern Utah). Also, I have the crazy idea of trying some photography, perhaps using picture stacking software, though that's really not much of a priority in trying to make my decision.
One last thing. If you pop for either of the scopes, be sure to spend an extra $15 on a set of Bob's Knobs. These are little thumbscrews that replace the collimating screws on the scope. Depending of Celestron's mood, they give you either phillips head or hex head collimating screws. To collimate, you have to stand in front of the scope, just hoping you don't scratch your corrector. And you've got to keep track of the tool. With Bob's knobs, you can easily reach the adjusters while at the eyepiece. Collimation changes from a chore to a piece of cake.
Thanks for the advice. That sounds like an excellent idea. -- --Chris Russell
Chris Russell wrote:
I've decided that an 8" Schmidt-Cassegrain is just the ticket and I think I've narrowed it down to these two models which are in my price range and appear to have all the features I want:
Option #1: Celestron Nexstar 8i Product Information: http://www.celestron.com/prod_pgs/tel/nx8ise.htm
Option #2: Celestron C8-SGT Product Information: http://www.celestron.com/prod_pgs/tel/c8sgt.htm
I agree with the others. Fork mount is more user friendly, especially for a portable scope.
Does anyone know of any issues with Celestron's quality?
During the many years I sold telescopes at the late, great Hansen Planetarium I never had to return a Celestron for repairs. Alas, I can not say the same for the other brands we sold. Disclaimer: I've been out of the business for a few years and I suppose it's possible things could have changed.
there any other brands/models you would recommend?
I really like the Dobs from Orion but if overall size is a problem and the price does not scare you off, S/C is probably a better choice. Patrick
Patrick Wiggins wrote:
During the many years I sold telescopes at the late, great Hansen Planetarium I never had to return a Celestron for repairs. Alas, I can not say the same for the other brands we sold.
Unfortunately my Meade has come under my "knife" many times in attempts to repair defects and problems with the design (though never with the optics, just with the cabinet and tube). I'm getting my hopes up that, if I get one of these Celestrons, it will be a little better designed and more problem free. Thanks.
Quoting Patrick Wiggins <paw@wirelessbeehive.com>:
Does anyone know of any issues with Celestron's quality?
During the many years I sold telescopes at the late, great Hansen Planetarium I never had to return a Celestron for repairs. Alas, I can not say the same for the other brands we sold.
Disclaimer: I've been out of the business for a few years and I suppose it's possible things could have changed.
Patrick, I have 3 of the "other" brand and they all work great. Of course, being in the next room, I'm sure they feel the foundation shake and smell the gunpowder everytime I test fire a weapon, so maybe they are just behaving themselves... ;)
diveboss@xmission.com wrote:
Patrick, I have 3 of the "other" brand and they all work great. Of course, being in the next room, I'm sure they feel the foundation shake and smell the gunpowder everytime I test fire a weapon, so maybe they are just behaving themselves... ;)
Now, Guy, I wasn't just referring to _that_ brand (funny how most everyone knows which brand we're talking about). In fact we also had our share of problems with Tasco (yes, I hate to admit it but for a mercifully short time someone had the "great" idea to try selling Tascos). And it's hard to forget the day a box of Edmund "Cherry Bombs" arrived with all of the secondary mirrors rolling around inside the tubes. But I stand by my statement that during all my years there I never had to return a single Celestron for repair. Patrick (running for cover) p.s. Care to bring those "other" scopes to SPOC tonight for the Messier marathon? Just be sure and bring the cat box you suggested for under the Big Scope viewing position...
Quoting Patrick <paw@wirelessbeehive.com>:
p.s. Care to bring those "other" scopes to SPOC tonight for the Messier marathon? Just be sure and bring the cat box you suggested for under the Big Scope viewing position...
Hate to be the bearer of bad news Patrick, but it's going to be cloudy tonight. So unless someone will be running all 110 objects using a radio telescope, I will probably wait for it to come out on HBO ;) Bundle up!
participants (6)
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Chris Russell -
diveboss＠xmission.com -
Don J. Colton -
Michael Carnes -
Patrick -
Patrick Wiggins