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ES TwiLight I Capacity Mount Questions vs Others

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#1 spongebob@55

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Posted 10 January 2014 - 08:42 PM

I have 2 scopes, a 6" SCT and a 102mm f9.8 refractor. I'm seriously thinking of getting the Twilight I. its rated at 15lbs. I weighed both scopes after fully loading the scopes with all the heaviest EP, diagonal, finders, and anything else I could possibly use, at its heaviest. The SCT weighs in at 14.2 lbs and the refractor at 13.2 lbs.
My question is....is the 15lbs they quote accurate and am I too close to this 15 lbs at these scope weights?
(Seems strange that the Astro Tech, GSO and similar clones are rated at 20 lbs). To me, the Twilight looks stiffer, with the tubular legs and metal spreader.
Thanks for your input.
Sbob

#2 hottr6

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Posted 11 January 2014 - 10:11 AM

Sorry, no experience with the Twilight, but I do have an AT Voyager. My Voyager with stock aluminum tripod and extension pier is optimistically rated.

In the following discussion, OTA weights are given that include dewshield, rings, dovetail, finder shoe and 2" eyepiece extension tube, but no caps, finder, eyepiece or diagonal.

The Voyager seems well-suited to carrying a 6" MCT (11.8lbs, no rings), 6" f/5.3 Schmidt-Newt (12.5lbs, no rings), 4.5" f/8 Newt (6.8lbs) and 5" f/5 Newt (9.0lbs) and C80ED (7.0lbs), and marginal with a 6" f/5 Newt (12.9lbs).

The Voyager is overloaded with a 3.5" f/11 achro (7.7lbs) and 102ED f/7 (9.1lbs). WTH??

You can see the pattern. The Voyager is happy with short, reasonably heavy payloads, but once the tube length gets long, it is decidedly less happy.

If the Twilight is anything like the Voyager, it should be quite happy with your SCT but you will hate it with the 'frac.

#3 Pinbout

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Posted 11 January 2014 - 12:52 PM

I've got a dsv-1 you can borrow, I'm not selling it but you can see how this style works with that scope. :p

#4 JonNPR

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Posted 11 January 2014 - 01:47 PM

Sbob, I often see experienced mount owners on CN recommend cutting the advertised load rating in half for optimal operation. That said, I am using a Twilight I head on an Oberwerks tall tripod with a long refractor that weighs about what your scopes do, when loaded with all accessories (8x50 finder, rings, dovetail) and my heaviest eyepieces. The slow motion controls work quite smoothly. However when pushing the scope about with the clutches open the Twilight tends to struggle a bit under the weight.

Your experience when using the Twilight mount on its stock tripod might be better, but realize you are indeed pushing the limit of even the manufacturer's specs.

Jon

#5 OrdinaryLight

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Posted 11 January 2014 - 03:15 PM

For not too much more than the cost of a Twilight I, you can put together an Oberwerk blem tripod ($129 + $16 s/h) and Vixen Porta II head ($170-$190). The adapter included with the Porta head takes an M10 bolt so you need to adapt the head to the Oberwerk. Here are some threads that show a few different ways to do this:

http://www.cloudynig...?Number=6154401
http://www.cloudynig...?Number=5070283
http://www.cloudynig...?Number=5796175

With the 102GT f/9.8 mounted vibrations damp in 3-4 seconds @100x. With a slightly heavier but shorter 102mm f/7, vibrations damp in 2-3 seconds.

The Porta head comes with the M10 adapter base (not used in my setup), slow motion cables and a tray that fits the Oberwerk tripod spreader perfectly. IMHO, they make a good looking pair:

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#6 spongebob@55

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Posted 11 January 2014 - 04:18 PM

Sbob, I often see experienced mount owners on CN recommend cutting the advertised load rating in half for optimal operation. That said, I am using a Twilight I head on an Oberwerks tall tripod with a long refractor that weighs about what your scopes do, when loaded with all accessories (8x50 finder, rings, dovetail) and my heaviest eyepieces. The slow motion controls work quite smoothly. However when pushing the scope about with the clutches open the Twilight tends to struggle a bit under the weight.

Your experience when using the Twilight mount on its stock tripod might be better, but realize you are indeed pushing the limit of even the manufacturer's specs.

Jon


Thanks Jon. I'be seen these discussions too, and they seem to make sense to me, along with the advice that it gets worse with a long OTA. That's why I loaded my 6" SCT and 102 f9.8 with the heaviest accessories I could put on.... even a dove tail weight to push the center of gravity of the SCT forward, so the dovetail clamp isn't more than all the way back, and then weighed them. I was surprised how much weight all those accessories added up! But this is what must be done in order not to make mistakes, and then to get advice from CN'ers, which is the real life input.
But I want a true pick it up, spread the tripod legs and point away, with some slow motion available. I guess I could do that too with a small GEM, but I've yet to look at those yet.......CG4 or CG5 I guess? Nothings ever easy, is it? Of course, with this lousy weather, I have some time!
Thanks
Bob

#7 spongebob@55

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Posted 11 January 2014 - 04:44 PM

For not too much more than the cost of a Twilight I, you can put together an Oberwerk blem tripod ($129 + $16 s/h) and Vixen Porta II head ($170-$190). The adapter included with the Porta head takes an M10 bolt so you need to adapt the head to the Oberwerk. Here are some threads that show a few different ways to do this:

http://www.cloudynig...?Number=6154401
http://www.cloudynig...?Number=5070283
http://www.cloudynig...?Number=5796175

With the 102GT f/9.8 mounted vibrations damp in 3-4 seconds @100x. With a slightly heavier but shorter 102mm f/7, vibrations damp in 2-3 seconds.

The Porta head comes with the M10 adapter base (not used in my setup), slow motion cables and a tray that fits the Oberwerk tripod spreader perfectly. IMHO, they make a good looking pair:


Great information and links. Let me take a look.....
thanks
Bob

#8 spongebob@55

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Posted 11 January 2014 - 04:45 PM

thanks Danny, but the website says its good for up to 102mm f/7's, and my 102 is a f9.8, not to mention I have to buy a tripod too.....unless I could put it on my Atlas EQ-6 tripod. But I think it would still be under mounted.

Dag should I be looking at a small GEM then?

Thanks and would you do something with this blanking weather?
Bob

#9 spongebob@55

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Posted 11 January 2014 - 06:00 PM

so why does the Porta II and Astro Tech Voyager have a 20lb capacity, whereas the Twilight I have a 15lb capacity? I seems to be that the Twilight is built better with the tubular legs and the metal leg spreader/EP holder. I had a Porta II years ago before I went bigger scopes, and I wasn't impressed by the aluminum legs and plastic fold out spreader. I even bought a pie pan, drilled a hole in its center, and used to stiffen it up and hold all my stuff.
Are is the Porta and Astro Tech and GSO overstating, or is the ES understating? Or is there something the way theyre built that validates these 20 and 15lb capacities?
Thanks
Bob

#10 JonNPR

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Posted 11 January 2014 - 06:11 PM

Bob, I use the Twilight mount head (similar, perhaps the equal or better of the Porta II?) on the Oberworks tall blem tripod. That's similar to Danny's suggestion. I also have what sounds like the long 102 you have - the ubiquitous and fine Celestron model. It's loaded with the 2" diagonal, a Orion dual finder stalk carrying an 8x50 RACI and an RDF, and usually a heavy SWA or Baader Hyperion long focal length EP.

Vibrations settle quickly and the slow motion controls make higher magnification tracking smooth enough. Focusing at higher powers is not so great, but I haven't replaced or worked especially on the stock focuser (yet). It isn't a big deal, just requires more patience. Balance, though, is interesting.

The long OTA makes it challenging to balance so that the front lens cell end doesn't crash downwards without the clutch tightened...and also not positioned so far back towards the rear that the EP end won't stay where you place it when tilted up at higher altitudes. Because of the alt az method of placing the center of gravity to the rear of the tripod center, I've found that at that sweet spot of front/back balance, the rear/eyepiece end will tend to be near the backward tipping point of the tripod! So I keep a tripod leg aligned with that EP end, just in case.

So at least despite the wise cautions about cutting the advertised load capacity in half, this set up and The stock steel tripod as well works well enough (The stock tripod is just too low for comfort for me). But the binding I mentioned above was puzzling and after your post here, I investigated further.

I disassembled the mount head and removed the azimuth nut from the base. The disturbing almost grinding-like sound I was hearing and feeling in one section when rotating the mount disappeared when I replaced the nut and its washer and tightened it sufficiently. The head rotated smoothly again, with no rough spot at any point.

After reassembling the mount and testing it on both the stock tripod and the Oberwerks, the action remained very smooth with the entire C102 package riding. I don't know what caused the binding. The azimuth nut felt quite tight when I initially checked it before removing it. Maybe it was too tight, but the slight tilt I observed where the binding was occurring suggests too loose. Weird.

Time will tell whether the weight of the scope, in the vicinity of what yours weighs, was the cause of whatever was involved with the azimuth bolt and rotation. Right now it is smooth as butter. And I think from pictures here and elsewhere of the Portamount that it might be less robust than the Twilight.

In terms of Grab and Look-or-Go, that's how I have this set up. Ready to pick up and carry fully assembled out the back door, or slip the OTA in its padded bag and quickly put it and the tripod in he car and drive away to a nearby better site.

Hope this helps!

Jon

PS The Twilight mount attaches directly to the Oberworks tripod because the tripod ships with an adaptor plate that fits the Twilight bolt.

#11 OrdinaryLight

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Posted 11 January 2014 - 06:12 PM

It seems weight ratings are tricky. In addition to variables like OTA length, there is the question of what the baseline is. If the goal is a setup that performs well (e.g. reasonable dampening times and smooth movements), this is all very subjective. So I can see how ratings can vary widely on similar mounts.

#12 JonNPR

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Posted 11 January 2014 - 07:05 PM

Very good point, Dave. I believe that some degree of the "reduce rated payload by half" advice may apply to quality for imaging. The degree of dampening a person tolerates for visual observing must vary some, from person to person.

Jon

#13 stevew

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Posted 11 January 2014 - 07:13 PM

I have this mount, and it works great with my C5.
No vibrations, and very smooth slow motion controls, but when I put a 102 F-6 achromat on it the vibrations limit it's use to low and medium power.
And while I do like the steel legs, it's a bit too short for getting behind the Telrad to find things. It's fine from a seated position.
I still find myself looking at the Vixen Porta II

Steve

#14 Pinbout

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Posted 11 January 2014 - 07:16 PM

whatever head you get, buy the oberwerks tripod, blem or not. that will make or brake your head. I'd like to see how your f9 works on my head I made

Posted Image

#15 JonNPR

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Posted 12 January 2014 - 01:41 PM

For comparison, with a 102GT mounted and legs fully extended, the Twilight 1 stands roughly at or below the height of the Oberwerks TALL blem, WITHOUT extending its legs. AFAIK, the height of the Porta II is roughly similar to the Twilight.

The advice on the Oberwerks Tall tripod is excellent for those using a long focal length refractor! And they are beautifully crafted.

Jon

#16 spongebob@55

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Posted 12 January 2014 - 07:19 PM

So a point I might have missed.....does the wood tripod only look great or does it have some dampening or better stability effect?
Thanks
Spongebob

#17 JonNPR

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Posted 12 January 2014 - 10:09 PM

Yes, it looks great. The wood and its grain is attractive and it is nicely finished. I bought a blem model and I guess it has a very small scrape on one leg but I never see it. Wooden legs are reputed by experts here to have better dampening characteristics than metal. If you think about the nature of hollow metal tubes and solid wood, that makes sense.

Jon

#18 spongebob@55

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Posted 16 January 2014 - 02:58 PM

whatever head you get, buy the oberwerks tripod, blem or not. that will make or brake your head. I'd like to see how your f9 works on my head I made

Posted Image


Hey Danny,
Sure, lets try it. Let me know when you're going to Wawa and I'll bring it along. That's if it ever clears up around here! Hasn't it been ridiculous?!
Bob

#19 Pinbout

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Posted 16 January 2014 - 04:04 PM

whatever head you get, buy the oberwerks tripod, blem or not. that will make or brake your head. I'd like to see how your f9 works on my head I made

Posted Image


Hey Danny,
Sure, lets try it. Let me know when you're going to Wawa and I'll bring it along. That's if it ever clears up around here! Hasn't it been ridiculous?!
Bob



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