Author Topic: (Actual) Weight Limit for Nexstar SLT Mount  (Read 159 times)

birchzufhyro

  • Active Astronomer
  • ***
  • Posts: 100
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
(Actual) Weight Limit for Nexstar SLT Mount
« on: December 24, 2017, 06:07:41 PM »
Hi all,

I've a question about the weight limitation for the NexStar SLT mounts.

I have an SLT 127 using the bracket that came with it.  I've read (for instance, here:http://www.cloudynig...star-slt-mount/ and here: http://www.cloudynig...xstar-127-slt/) that the mount's weight limit is approximately 8 pounds, along with the optical tube is approximately 8 pounds (maybe a little bit less).  My understanding is that it has already at/near that the "official" weight limitation.

I've been trying to shoot some basic images (planets, the moon, that sort of thing) by holding my camera up to the eyepiece (which hasn't actually turned out that bad...) but for Christmas someone gave me the camera adaptor (http://www.celestron...apter-universal) which is actually sort of thick (about a pound), along with also the camera adds about another half a pound.

My concern is whether this will be too thick for the bracket.  I balanced the tube using the camera adaptor & camera on it, and when mounted it does not slide.  I'd use the control to move the tube around (just a bit) and did not hear any gears clicking, etc..

My questions are:
1) Can this set-up too thick for the bracket?  (I'm using x-cel eyepieces, which adds some weight also but not too much.)
2) More generally, what signs should I be searching for to know some set-up is too thick for the bracket?  I don't wish to damage any of these gears or anything.

Thanks everybody & clear skies!



portfreqportri

  • Active Astronomer
  • ***
  • Posts: 125
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #1 on: December 27, 2017, 02:51:29 PM »
Mount specifications are not hard and fast. In addition, besides the weight, the length of the OTA also matters. The 127mm Mak is relatively short so that is a good thing. In the short term, the added weight of the camera adapter should not be a problem and in the long term, it might shorten the life of the drive train somewhat but if it were me, I would just do it..

Jon

longpetdowntown

  • Active Astronomer
  • ***
  • Posts: 114
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #2 on: December 30, 2017, 11:56:27 AM »
The biggest issue with the SLT mount comes from the tripod and not the ability of the Mount itself.
I put a set of vintage wooden legs on my SLT and it carried a Celestron C6 SCT easily.
You are going to have trouble getting any decent photos, with the way it was mine shook for 6 or 7 seconds. The wood cut that down to about 2 seconds.
I don't know why the Chinese put such obviously undersized legs on their mounts. The Celestron 6 and 8 SE Nexstars are about as bad. While the 6" is OK, the same mount was used for the 8" the result is very bouncy.

whoopsirode

  • Active Astronomer
  • ***
  • Posts: 120
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #3 on: December 30, 2017, 03:02:39 PM »
Changing the tripod is one of the best upgrades you can do for the SLT mount. Though it is "rated" as 8lb capacity I normally load mine to 10-12 lbs.
With an aluminium tripod from an EQ-3 and vibration pads the shakes last hardly over 1 second.

Elijah York

  • Active Astronomer
  • ***
  • Posts: 112
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #4 on: December 31, 2017, 04:41:56 PM »
I don't know why the Chinese put such obviously undersized legs on their mounts.
To reduce the price of the package. imho

gausinoleac

  • Active Astronomer
  • ***
  • Posts: 122
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #5 on: January 08, 2018, 11:26:51 AM »
Quote
I don't know why the Chinese put such obviously undersized legs on their mounts.
To reduce the price of the package. imho

I think that is just about it. When the CG-5 ASGT was introduced, Celestron upped the ante with the 2 inch diameter Stainless Steel legs, that was a vast improvement over the previous legs, extruded aluminum legs.

Jon

Dennis Collins

  • Active Astronomer
  • ***
  • Posts: 126
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #6 on: January 09, 2018, 02:19:59 AM »
It seems Celestron has always been behind the 8 Ball when it comes to their Tripods. Their Silver locking
tripods were not heavy enough for the C8. Criterion had a vastly superior tripod with their Golden Tripod.
which suspiciously looks like Mead's Field tripod from the 80's on up hmmmm  .
But it is hard to replace a good hardwood tripod. I said mine was around 2 seconds, that is with a good "RAP" on it, about 1.5 seconds. I honestly think the SLT is a very under rated mount. I have owned 2 (I still have one) The Go-To is very good, the object is always in the field of view with a 20mm eyepiece.
I haven't had a breakdown, and they weren't as "sloppy" in axis as my N-Star se mount.
Battery life is also a bit better too.
My 127 SLT was so shaky, I had to sit on the ground with the tripod legs fully retracted. It still bounced for about 5 seconds.
I have an old 120mm F5 on it now it is a heavy little guy sitting in the closet just waiting for a mount. Now it is about my most used scope!

Bill Godschalk

  • Active Astronomer
  • ***
  • Posts: 119
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #7 on: January 10, 2018, 02:03:47 AM »
I own Nexstar 130SLT, the same mount. With original supplied andmirrorless camera, scope tracking is fine enough for short exposure. I can always get 80% pin-point star at 5-sec.

As you concerned, SLT mount is likelyreach it's limit with supplied 130mm Newtonian scope. However,overload is possible as the altitude (vertical) axis use gear+tension clutch which will slip instead of broken in case your equipment is not in balanced or too heavy.

I used to addsome overload to the mount about 1-2 kg by attachDSLR camera on the optical tube (before I make DIY mount for DSLR). Mount will become more shaky and tracking accuracyispoorer but no sign of broken. Camera shutter will makes scope tracking slip from original position. You will find this when combine multi-exposure to a single video. This likelynot happen whenjust taking a video.

My opinion, SLT mount is cheap built (also it's cost). So,try whatever you want and learn fromit.When it die,it will bea good time to moveto something better and take them a good care.

tialegofi

  • Active Astronomer
  • ***
  • Posts: 121
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #8 on: January 10, 2018, 06:37:27 PM »
http://astrob.in/93670/C/

http://astrob.in/119234/0/

I shot these with a 4" refractor. The payload was around 4.5kg and the refractor's lenght was for sure more punishing compared to a compact 5" MCT/SCT.
Furthermore, the refractor's cradle pushed the OTA center of gravity outside the tripod's own center of gravity, causing an unbalancing on the azimuthal plane impossible to fix
It was not a very pleasant experience (had to work a lot to proper tune the anti-backlash); the SLT apparently did not suffered damages

grountentaybrig

  • Active Astronomer
  • ***
  • Posts: 128
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #9 on: January 10, 2018, 10:35:52 PM »
Hesoid I load my SLT over 4.5 kgs on a regular basis. 102mm refractor, Herschel wedge, binoviewers, etc and have no issues with balancing all the gear. From your description I would assume you need a longer dovetail to get more adjustment. I use an 8" on my normally but have used a 10" before.

cromsotejbi

  • Active Astronomer
  • ***
  • Posts: 117
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #10 on: January 11, 2018, 03:30:49 PM »
No, I can properly balance the refractor on the altitude plane. The fact is that the refractor ends up too much on the left because of the height of the cradle and vixen adapter.
Anyway, I did not have a good feeling with such setup so downgraded to a 90/1250 Mak or a 66/400 tiny refractor for the WL Sun.

Jeremiah Greer

  • Active Astronomer
  • ***
  • Posts: 134
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #11 on: January 12, 2018, 08:48:12 AM »
According to Celestron, the SLT mount has an 8 pound weight capacity:

http://www.celestron...oad-capacities-

unllamerblood

  • Active Astronomer
  • ***
  • Posts: 132
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #12 on: January 15, 2018, 01:21:46 PM »
The stated weight capacity is exceeded by many people with no issues quite often. I believe the 127 Mak they sell with the SLT is 8lbs without accessories. They are good mounts with unfortunately very flimsy tripods.

latorika

  • Active Astronomer
  • ***
  • Posts: 116
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #13 on: January 16, 2018, 03:55:12 AM »
Indeed. The meaning of my first post was to encourage the OP, because my SLT did not suffered any damage even under more severe circumstances (long, partially unbalaned refractor). A 127/1500 MCT is more compact and will put less stress on the SLT; however, as Gabby76 noted, a longer dovetail may help to get a good balancement on the altitude plane if the OTA is very back-heavy: when I use the binoviewer, the 90/1250 is entirely after the clamp (the binoviewer block and the OTA are both roughly 1 kg...).

The 127/1500 can be a quite amazing telescope for planetary imaging, especially if a planetary camera (or a modded webcam) is employed.

Waka Belcher

  • Active Astronomer
  • ***
  • Posts: 131
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: (Actual) Weight Limit for Nexstar SLT Mount
« Reply #14 on: January 17, 2018, 08:39:20 AM »
Thanks all! I feel much better about trying this out!