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What OTAs could fit on a celestron nexstar 114 mount


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Hi All

I've got a Celestron Nexstar 114SLT on the stock nexstar goto alt/az mount

When it comes to upgrade time, does anyone know what else I could fit on the mount (dovetail fitting) and still have accurate goto and tracking performance?

Is the weight of the OTA the limiting factor?...if so what would the max weight be?

...would it handle a 6inch mak/sct (nexstar 6 OTA or a skymax 150 for example), or a longer refractor such as an evostar 150

Thanks in advance for the advice

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I've mounted both a Celestron 80ED and a Skymax 102 on mine without issue. The NexStar SLT handles either, and goto and tracking remains accurate. I have used the SLR with the 80ED and my 450d mounted on it, tracking wasn't good enough for longer than 15 second exposures, but that's a 1/2 Kg heavier with an odd weight distribution. As I understand it, that mount is basically the same as the Skywatcher AltAz SynScan mount so should handle the Skymax 127 ok. Beyond that, I can't say, sorry... I've not got anything else to try on it.

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I think you will find that weight-wise you are pretty limited to the 127 Mak, 130 Newt, or 102 refractor. However, I find it works a treat with my Onyx 80mm ED (which is lighter than the stock 102), which is why I hung on the mount for a grab-&-go.

M.

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Rob and myself tried loading his SLT mount with various scopes to see what it could handle and still remain useable.

With the legs retracted for max stability it could take the Skymax 127. But with the legs extended (which ideally you would want with that type scope) it was as wobbly as jelly.

The best combo turned out to be an Orion (Skywatcher) ED80 and the SLT. Still wobbly with the legs extended but useable. GOTO still worked without fault.

I can't see that mount handling a 6" Mak or SCT, even with the legs retracted.

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Thanks for the quick responses, it's useful to know the limitations of the kit

It will probably be a while until upgrade time for me, but I wanted an idea just in case a bargain pops up...I spotted an evostar 150 ota on ebay which got me wondering...I wont bid!

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I did some testing a while ago and found that the 127 Mak or the C5 SCT OTAs are an ideal match. Also 80mm refractors worked well or you might consider a Zenithstar 70 or Megrez 72 as they make for a great grab'n'go setup that needs almost no cooling down time at all.

The Skymax 150 however is simply too heavy. I have heard of the C6 SCT OTA (a lot lighter than the 150 Mak) being fitted, and it was supposed to be usable, but I've not seen that for myself.

The CG5 or EQ5 tripod legs won't fit as the mounting points at the top are totally different.

John

Edited by johninderby
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I think the problem is, even if you could put a more robust tripod under it, I don't think the mount head could cope with a heavier / longer OTA than those already suggested. The motors and gears in it can only cope with so much.

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I agree. Replacing the legs will help the 5" ota's for stability, especially at full height but the 6" scopes (Skymax 150 definitely) are beyond this mount. The lighter C6 may just be usueable but damp down times could be poor, which could make it a frustrating experience.

There was a member of SGL who successfully updated his SLT legs with nice wooden ones. It was sometime back now, perhaps 2006/7 and i can't remember who the member was. Not much help...sorry.

Russ

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Were the tests carried out with the aly tripod, or the stainless? I have the stainless, which is supposed to be better, although it is a bit wobbly. Sticking a lifting-weight on the eyepiece tray, and putting some pads cut out of camping mat helps to damp it down. The wobble is mainly from focusing, and a crayford helps with that, and I guess an electric focuser adapter would improve it even more. Maybe an SE tripod would fit? Aternatively, if you are upgrading the scope and the tripod, why not sell it and upgrade the whole thing? Then you could have an SE or Meade equivalent, or an EQ mount & whatever-scope-you want package. Or, if you can afford it, upgrade and keep the SLT for grab-and-go.

M.

Edited by MishMich
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I have the stainless legs on mine, I never really lifted the legs up very far, I've only used refractors and sitting means you don't need it to be very high. Focusing was always when the wobbles became worst, more so with the longer FL Mak than the fracs. But once focused, the little SLT works perfectly well for visual with all three.

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There is an easy way to use a heavy duty photo tripod if you wanted to.

When the SLT mount is removed from the tripod you will see a small steel plate that is screwed onto the bottom of the head. The centre hole in the plate is a standard 1/4 photo tripod thread. Reverese the plate and it now sticks down far enough to screw the correct photo mounting plate on.

The key part is a Manfroto 357 Sliding Adaptor Plate. This plate is narrow and long enough to fit properly.

http://www.warehouseexpress.com/buy-Manfrotto-357-Sliding-Plate-Adaptor/p11044?cm_mmc=GoogleBase-_-Tripod-Heads-_-Quick-Release-_-Manfrotto-357-Sliding-Plate-Adaptor_11044

The long plate on the 357 adapter is then fastened onto the bottom of the mount and the base part is fastened onto the photo tripod.

Now you just need the right heavy duty photo tripod.

I can take a photo of the arrangement if you wish.

John

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Ok here's a few photos of the Manfrotto 357 adaptor fitted to a SkyWatcher AZ GOTO mount (didn't have an SLT to hand but they are the same).

The Manfrotto 357 adaptor consists of a dovetail plate and a dovetail saddle that fastens directly to a photo tripod with a standard 1/4 fitting. It's a well made item that also has a safety catch so that when the dovetail plate is slid into place a safety catch engages which prevents the dovetail plate from being removed unless a safety catch button on the side is held down.

There is no modification needed to the SLT mount as the only thing you're doing is unscrewing a mounting plate and turning it upside down. The first photo shows the little mounting plate on the bottom of the mount turned upside down.

John

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  • 6 years later...

I have been dissatisfied with the wobbliness of the Nextstar tripod.  I also have an EQ-5 stainless steel tripod which is an order of magnitude more stable.

Re. the discussion above about the Manfrotto, I had a look at the underside of the Nextstar mount. It is clear that it could be securely mounted by a single 1/4" screw onto a flat metal plate or board, which is a useful thing to know if you are thinking of making your own adaptor.

Vixen have a 1/4" to tripod adapter, which might work for you if you have one of their tripods. 

In engineering terms, it ought to be possible to make an adapter to fix the Nextstar mount to any solid tripod (e.g. by reworking an EQ-5 extension pillar) or adapt it to a pier top plate, but the question is will this be more cost-effective than upgrading the whole kit? Unless you already own a suitable tripod and some bits, I fear it isn't.

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