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nodalpoint
scholastic sledgehammer


Reged: 06/03/13

Loc: FEMA camp
For those considering the NexStar mount new
      #6046064 - 08/25/13 09:52 PM

The following is one guy's opinion for anyone considering the purchase of a scope on the NexStar mount. After much debate and a little hand wringing, I purchased a NexStar 8 in July. At first I was going with the 6 inch but helpful advice here convinced me to go with the bigger aperture of the 8. I've found the move up to be a wise choice as my fears of portability were unfounded and the extra cost was worth the extra reach of those two inches. But one nagging item was the stability of the larger ota on the NexStar mount several members expressed.

I've had the most amazing time with my scope, my first real scope btw, and love seeing all the things I've read about since a kid. So of course I'd have to get into imaging and that's why a shiny new AVX mount arrived yesterday! Now for the opinion.

After one night using the AVX with the 8" ota mounted I've realized the NexStar mount was simply too frustrating due to vibration and pointing at objects near zenith. I'm only talking visual observing as it would be unfair to mention imaging, but even with the NexStar's tripod as low to the ground as possible and on a solid surface I get a ton of vibration. Every time I touch the focuser I'm battling the shakes. Brushing the eyepiece or the mount does the same. Last night being at the end of a rock solid mount I realized the extra weight and bulk of the AVX was worth the benefit of the much better views.

So anyone out there thinking of getting a NexStar, they are awesome and totally worth it. Don't think I'm down on them. But loading up the bigger ota on the arm mount in my opinion is too jittery. The AVX versions of the scopes are a bit more but unless portability is the top priority, I'd recommend them over the arm mount. Plus, you can always pick up a new or used NexStar mount down the road for a travel package/grab and go.

Hope people understand where I'm coming from and I'm not trying to diminish how awesome the NexStar is, but anyone about to pull the trigger might want to look at all the options.


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Midnight Dan
Postmaster
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Reged: 01/23/08

Loc: Hilton, NY, Yellow Zone (Bortl...
Re: For those considering the NexStar mount new [Re: nodalpoint]
      #6046111 - 08/25/13 10:22 PM

There's no comparing an SE mount to a GEM. My iEQ45 blows away the SE mount any day in terms of stability.

BUT ... the SE mount is extremely portable, easy to use, lightweight, and quick to set up ... something I can't say about the iEQ45. Fact is, after using the iEQ45 a few times for visual, I found myself not wanting to go through the setup time and effort and instead always reach for the SE. Yes it's shaky, but I can be out and observing in very little time and that's important to me. Its a tradeoff. The iEQ45 is rock solid, the SE is quick and easy ... take your choice.

Once I have my observatory set up, the iEQ45 will be in there and permanently mounted on a pier and aligned. In that case, I will be able to observe quickly without the setup time, AND enjoy the stability of the GEM mount. At that point I probably won't use the SE mount except for travel to dark sites and star parties.

By the way, being on a solid surface is the worst case for vibrations. When you touch the focuser, the vibrations travel down the tripod legs and are reflected back up and down like a tuning fork. If you put the tripod on a soft surface, like a lawn, the dirt will absorb the vibrations and not reflect them back up as much. That will improve the vibration settling time quite a bit. Anti-vibration pads do the same thing and work on any surface. I use them all the time. They don't fix the problem, but they reduce it by about 50%.

-Dan.


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AhBok
sage


Reged: 12/02/10

Re: For those considering the NexStar mount new [Re: nodalpoint]
      #6046118 - 08/25/13 10:25 PM

This is why I personally prefer the SE6. It is a good match for the one-armed fork and tripod. I have a CPC800 for my 8" scope and it is very solid and stable. I previously had an SE8 and though it worked quite well, the vibrations were ultimately the reason I downsized to the 6" for my travel scope. I've used a SE8 on a CPC tripod, however, and it was very stable, so I concluded the one arm fork is not really the problem. I think it is just difficult to get a highly portable, lightweight 8" SCT. Still, I think many would be willing to sacrifice some stability to have that much aperture in a feature-rich, lightweight package.

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AstroTatDad
Pooh-Bah
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Reged: 04/22/13

Loc: Los Angeles - San Diego
Re: For those considering the NexStar mount new [Re: AhBok]
      #6046257 - 08/26/13 12:27 AM

for me putting down carpet and using the vibration pads on hard surfaces had cut the vibrations down a lot. since I have picked up the CG 5 it's been great. but I'm only using it for AP, I'm fine with the SE mount for visual.

But grass and putting down carpet with the pads has worked for me, I flicked the diagonal for a test and maybe get a second of vibration. focusing as well is not bad, yes you have to be gental but it's not bad for me anyhow.


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AstroTatDad
Pooh-Bah
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Reged: 04/22/13

Loc: Los Angeles - San Diego
Re: For those considering the NexStar mount new [Re: AstroTatDad]
      #6046261 - 08/26/13 12:29 AM

oops forgot to add I do have the 6se so I guess you guys with the 8" with the extra 3 pounds, probably do see more vibration.

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Bob Griffiths
Getting Grouchy
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Reged: 10/10/05

Loc: Frederick Maryland
Re: For those considering the NexStar mount new [Re: AstroTatDad]
      #6046587 - 08/26/13 09:10 AM

I own a couple of refrators that are Gem mounted..one GoTo and one manual,, and I also own an 8i as well as a CPC1100...

I HAVE to agree with you about shakes with my 8i BUT ONLY WHEN I TOUCH the focus knob...easy solution is just to AVOID touching that knob...

A Motofocus eliminated the need to even touch the scope...PROBLEM SOLVED...add mounting the scope on my CPC1100s' tripod or on an Antares 4 inch portable pier and the stability is more then adequate ...

As for viewing at Zenith. well I can even with the motofocus and a huge Denk S1 P/S diagonal hanging off the back of the scope (with Rays Brackets)BUT TRUTH BE TOLD...I rarely ever view at Zenith or even close to Zenith

I have about 7 pounds "bolted" on to my 8i OTA and I have no problem with shakes... PLUS it is 10 times easier for me to lug outside and align them my GoTo Gem (which holds a 5 inch refractor BTW)


MONEY can solve the shakes...(my way or a New Gem mount)...lol

Bob G
Bob G


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WarmWeatherGuy
Carpal Tunnel
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Reged: 08/27/11

Loc: Orlando, FL 28 N, 81 W
Re: For those considering the NexStar mount new [Re: Bob Griffiths]
      #6046645 - 08/26/13 09:54 AM

Quote:

I HAVE to agree with you about shakes with my 8i BUT ONLY WHEN I TOUCH the focus knob...easy solution is just to AVOID touching that knob...

A Motofocus eliminated the need to even touch the scope...PROBLEM SOLVED...
Bob G




You can also use a Bahtinov mask as I explain in this video:

How to focus a wobbly telescope

You might also have a vibration problem when it is windy as seen in this video:

Venus Celestron Nexstar 8se Red Filter

I suspect the problem with the 8SE is resonance. You might have less vibration by adding more weight to the OTA.


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CelestronDaddy
scholastic sledgehammer
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Reged: 08/22/09

Re: For those considering the NexStar mount new [Re: nodalpoint]
      #6046698 - 08/26/13 10:27 AM

This was one of the reasons I went with the 6SE rather than the 8SE. Now I haven't weighed the 6"OTA and the 8"OTA but I hear there is about 3 pounds difference. That may be or not be correct but I think the mount is well matched for the 6" and mine works just fine. If I saw a good deal locally on the bigger mount I might take a look but for now I'm quite happy with the performance of the mount with the 6" OTA...

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Peter9
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Reged: 10/30/08

Loc: Yorkshire - Born & Bred
Re: For those considering the NexStar mount new [Re: CelestronDaddy]
      #6047012 - 08/26/13 01:29 PM

When I upgraded from the 6se to the 8se, I followed Bob's advise and fitted a motor focuser which solved the vibration issue when focusing the scope. Main drawback is that its a costly solution. I also go along with Tony in that the mount is much more suited to the 6se than it is to the 8se.
As an aside, I found out last week, while trying to make a repair to a tripod leg, that the metal outer tripod leg only extends about 1" into the platic moulding around the bottom of the leg. That means the bottom 5" or more of the outer tripod leg is all plastic. Is this likely to cause more vibrations than if there were more metal extending deeper into the plastic moulding???

Regards. Peter.

Edited by Peter9 (08/26/13 02:23 PM)


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AhBok
sage


Reged: 12/02/10

Re: For those considering the NexStar mount [Re: CelestronDaddy]
      #6047031 - 08/26/13 01:43 PM

Just to add--it is not just the 3lb diff in weight and shorter length of the 6" vs. 8" OTA. I tend not to load the 6" up as much with a 2" diagonal and eps, preferring to use 1.25" to match the smaller rear port opening on the 6". Also, I use a f.63 focal reducer on the 6" for a FL Of 960mm which is, IMO, a good general purpose focal length for travel and G&G visual use. Finally, I use the stock Starfinder since its only purpose is for initial alignment. Contrast that with my C8 with accessory bar, counterweights, optical and red dot finders and 2" accessories. I tend to use the focal reducer less because I like to use the C8 on planets, globulars and planetary nebulae which rspond well to the native 2032 focal length. IMO, the SE mount is meant as a lightweight mount visual mount, so loading it up means trading off stability.

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CelestronDaddy
scholastic sledgehammer
*****

Reged: 08/22/09

Re: For those considering the NexStar mount new [Re: AhBok]
      #6047083 - 08/26/13 02:19 PM

Good point... I just use the 6SE for visual and I've got the same RDF on it. I am not adding any additional weight other than the EP and maybe a barlow. I use vibration pads too. What ever vibration there is from manually focusing is minimal and dampens in a second or so. The 6SE on this mount is a decent goto visual mount. If I started adding much more additional weight or if I had the 8" OTA, I'd upgrade to a heavier duty mount. For what it is though I think it is a decent mount with good goto accuracy, at least so far !!

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ben2112
scholastic sledgehammer


Reged: 07/12/12

Loc: North Charleston SC
Re: For those considering the NexStar mount new [Re: CelestronDaddy]
      #6047450 - 08/26/13 06:02 PM

Well.. My 8SE can be a little shaky when trying to focus manually. That is why I went with an electric focuser. I looked various models. The cheapest being $175 seemed a little high for me. So I built my own for a fraction of the cost. It fixed my shakes. I love my 8SE. The only reason I want to get a GEM is for DSO AP. You can't beat the setup ease. Within 10mins, I can have my scope setup and tracking. And within 10mins, I can have it torn down and back in the house.

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hawk
sage


Reged: 03/12/13

Re: For those considering the NexStar mount new [Re: ben2112]
      #6047791 - 08/26/13 09:52 PM

Quote:

The only reason I want to get a GEM is for DSO AP. You can't beat the setup ease. Within 10mins, I can have my scope setup and tracking. And within 10mins, I can have it torn down and back in the house.




Love that part, too. If I couldn't carry it all in and out in one piece, I'd have no time to observe at all these days.

I knew I was sacrificing stability when I chose the 8SE, but with the vibration pads -- and the fact that since I have only two high quality EPs right now -- I rarely have to refocus. Overall, it's not a bad tradeoff to make.

If I get more into AP, I'll get a GEM. If I decide to upgrade to a more stable scope for visual only, though, it may be a CPC or a giant Dob, but I'd miss the portability.


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AhBok
sage


Reged: 12/02/10

Re: For those considering the NexStar mount new [Re: hawk]
      #6047890 - 08/26/13 10:49 PM

I think these are important points. Though I have the SE6, the SE8 is a great package for those wanting the largest aperture you can get in such a lightweight package, with all the features you get with this mount. In this sense, there is nothing wrong with the SE mount, only trade-offs. If someone wants a mount capable of AP and superior stability, the trade-off is a much heavier, less portable and more expensive mount. The SE, IMO, is fine as is for either 6" or 8" OTAs for its intended use.

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nodalpoint
scholastic sledgehammer


Reged: 06/03/13

Loc: FEMA camp
Re: For those considering the NexStar mount new [Re: AhBok]
      #6047975 - 08/26/13 11:36 PM

Traveling to a nearby dark site, the SE mount is great for that. For carrying from inside the house to the porch or backyard, after removing the counterweight from the AVX it's not much more of an effort than for the SE.

I'm just looking at it from a value/bargain point of view. The NexStar mount is great and a blast to own but maybe an extra pound or two added for a better included tripod would make for a more stable platform.


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Muleya
sage
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Reged: 04/17/10

Loc: Harrisonburg, VA
Re: For those considering the NexStar mount new [Re: nodalpoint]
      #6048741 - 08/27/13 12:34 PM

My C8 is on the CG-5 mount. I was a little surprised by the weight of the mount when I first got it, but for the most part, the scope is rock solid when on it...even on a hard surface.

I do manage to carry mine out to the back yard in one piece...it takes a bit of effort, especially getting through the door, but not too bad.

One thought for an easy way of making the SE mount more stable. Back in the day, my grandfather increased the stability on his inexpensive Jason refractor by hanging a weight from the eyepiece holder on the tripod...I think it was just a lead disk weighing several pounds with a small hole in the middle and he fashioned a hook from a bolt or something with a washer on the end to hold the weight on. You could easily just use a counter weight made for a GEM...you'd just have to come up with a way to attach it securely...a bungee cord might even work.


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hawk
sage


Reged: 03/12/13

Re: For those considering the NexStar mount new [Re: Muleya]
      #6049001 - 08/27/13 02:37 PM

Yep, I've seen a few folks hang their powertanks off the eyepiece holder, so I assume it's a reasonably effective trick.

Also, I don't yet have a good chair, so I've got the tripod legs fully extended. That's a situation I could probably improve.....


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