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Mounting a TV-NP101 in Alt-Az

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#26 Lt 26

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Posted 11 February 2019 - 04:42 PM

I use the larger Gibraltar mount with the 5 head. The most improvement came from replacing the TV clamshell with a set of rings to hold the TV102. That gave me an attachment point for a DM 18" straight bar.

I place a 5lb padded weight in the eyepiece tray and have the TV eyepiece caddy, very handy. I don't care for side mount or single arm mounts.

When done correctly a scope floats on Gibraltar mount.

Dereck
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#27 terraclarke

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Posted 11 February 2019 - 04:54 PM

I use the larger Gibraltar mount with the 5 head. The most improvement came from replacing the TV clamshell with a set of rings to hold the TV102.


I do something similar.

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#28 rustynpp

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Posted 11 February 2019 - 06:13 PM

I would like to know if you can find a manual alt-az mount offering fine tracking control that’s stronger than the Porta2.

Haven't tried it, but perhaps the DSV-2 from Desert Sky Astro?

 

http://desertskyastro.com/DSV-2.html



#29 Jon Isaacs

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Posted 11 February 2019 - 07:10 PM

The M2 is sturdier than the Porta2 but if the OP plan to often manually track above 150x, the M2 is not the perfect tool for the job.

I would like to know if you can find a manual alt-az mount offering fine tracking control that’s stronger than the Porta2.

I was not able to find such a mount so I bought that M2 with the column and CGEM tripod.


(Maybe that thread should go in the mount forum).

 

The StellarVue MG-2 is obsolete but is certainly easily up to the task of the NP-101.  It handled my 120mm Eon, a 15 pound scope, very nicely. I would use it routinely up to 360X and occasionally up to 514x and found it steady.  It appears to be a single sided version of the Sky-Tee mount. 

 

https://www.firstlig...muth-mount.html

 

Jon



#30 Nippon

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Posted 11 February 2019 - 07:35 PM

Haven't tried it, but perhaps the DSV-2 from Desert Sky Astro?

 

http://desertskyastro.com/DSV-2.html

As long as you are not in a hurry. Desert Sky mounts are nice. I had one. But be prepared for a possible extended delivery time.



#31 Jon Isaacs

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Posted 11 February 2019 - 07:38 PM

That’s funny Jon, because what I see in the Mounts Forum is to stay away from the Porta II with anything greater than 10 pounds. I have a Porta II and I like it very much. It handles my featherweight Fujinon 102mm F6.4 with ease, but that OTA is short and slight. When I had my heavier Stellarvue 102mm F7 apo I used it some on the Porta (see my current avitar) and it was visibly getting to the mount’s weight limit. My TV Genesis SDF is considerably heavier and I wouldn’t even consider it on the Porta. My Gibralter on the other hand does fine with the TVGSDF. I have never gone above 216X with it (using my 2.5mm Vixen LV), and more frequently the upper limit of 180X (3mm TV delite) because of limited seeing, but the Gibralter is just fine!

When you read the mounts forum, you almost certainly have seen my voice among those pointing out the various issues with using a scope as heavy as the NP-101 on the Portamount.  I do not recommend it.  Even with the more robust wooden legs, it is too prone to vibration.  On the other hand, with a light touch, tracking at centering at high magnifications is doable.  With the Houston-Fearless tripod it is actually quite steady.  What tripod are you using with your Portamount?

 

The steadiness of the mount is a different issue than the tracking issue. What I read is that the bearings on Gibraltar are small and not easily adjusted for balance and tracking at high magnifications.  I am fine with fully manual tracking with a Dob, there's a much longer lever, more friction and mass, a Dob can be setup so it tracks nicely and does not need adjusting the balance while swapping eyepieces up to a kilogram or more. With the 22 inch, I have managed a bit over 1600x, mostly just to see if it could be done.

 

But with a refractor on an alt-az mount, balance and tracking complicate the issue, I consider slow motion controls a major plus, they allow greater friction so the NP-101 can be used with eyepieces like the 31mm Nagler without having to worry about the balance when swapping eyepieces.  And with a light touch, tracking at higher magnifications is doable with relatively short settling times.  In terms of real time focusing, the two speed Feathertouch makes a big difference. 

 

Bottom line:  For me, slow motion controls are a necessity for a scope like the NP-101, precise centering and tracking at any necessary magnification is just so easy.  The Portamount is not the ideal mount but with a sturdy tripod, it's workable.  The SV MG-2 as mentioned in my other posts is not perfect, there are a few things I would change if I could. But it is rock solid with an NP-101 and tracks smoothly and precisely with the slow motion controls at any necessary magnification.

 

Jon 


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#32 Jon Isaacs

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Posted 11 February 2019 - 07:46 PM

Haven't tried it, but perhaps the DSV-2 from Desert Sky Astro?

 

http://desertskyastro.com/DSV-2.html

 

The basic mechanical components of the DSV-2 looks essentially identical to the Sky-Tee and the MG-2. I wonder if the Sky-Tee/MG-2 were copied from the DSV-2 or if they were/are manufactured by the same manufacturer?  Based on the Desert Sky Astro Products webpage, it looks like the former.  

 

Jon



#33 Nippon

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Posted 11 February 2019 - 08:08 PM

The basic mechanical components of the DSV-2 looks essentially identical to the Sky-Tee and the MG-2. I wonder if the Sky-Tee/MG-2 were copied from the DSV-2 or if they were/are manufactured by the same manufacturer?  Based on the Desert Sky Astro Products webpage, it looks like the former.  

 

Jon

I had a DSV 1 which is the same basically as the DSV 2 but lacking slow motions. I also had a MG2 and there is no similarity at all except they are T shaped mounts. DSV mounts are made by a small company in Arizona.



#34 Passerine

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Posted 11 February 2019 - 08:10 PM

The StellarVue MG-2 is obsolete but is certainly easily up to the task of the NP-101.  It handled my 120mm Eon, a 15 pound scope, very nicely. I would use it routinely up to 360X and occasionally up to 514x and found it steady.  It appears to be a single sided version of the Sky-Tee mount. 

 

https://www.firstlig...muth-mount.html

 

Jon

Anyone who is interested in picking up a very lightly used Stellarvue MG2 Alt Az mount, send me a personal note.  I have one in excellent condition that I've been meaning to put up for sale along with the surveyors tripod that came with it.  It was my very first mount that I got with my first Stellarvue 4" scope.  I can let it go for a bargain price, especially to a local buyer (SF bay area).  I need to put it in the Classifieds.

 

Dave


Edited by Passerine, 11 February 2019 - 08:12 PM.

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#35 gwlee

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Posted 12 February 2019 - 01:38 PM

 

These scopes are definitely worthwhile at 200x, I go to 308x on close doubles.  In my opinion, an NP-101 deserves a mount that's solid and easy to track at such magnifications.  Otherwise, the mount is getting in the way of the scope and what it can do.  

 

Here, I seeing a lot of support for the Gibraltar but that is not what I have seen in the mounts forum.  Does it really allow easy, precise tracking at 200x, 300x?  Is it solid so real time focusing at 300x is doable?

 

These are my criteria, that's why I generally use the SV-MG2 rather than the Portamount.  The Portamount is not that bad at 200x-300x but it definitely vibrates in a breeze and vibrates while I am focusing..

 

This actually worked pretty well but the tripod weighs close to 30 pounds. Not quite grab and go.  Of course it's rated for 400 pounds so it would support the scope, me and my wife with some reserve.  

 

 
 
Jon

 

Except for low power sweeping, I found the TV Gibraltar wasn’t enough mount/tripod to support my TV NP101. The NP101 was rock solid on my DM6 Mount/tripod, but the combo weighed about 50#.

 

From these experiences, think the DM4 that I own now would be about right for the NP101, but I haven’t tried it. Tom Peters, owner of DiscMounts, says he considers a 4” refractor to be the sweet spot for the DM4, and we seem to have about the same tolerance of the shakes. Still looking for another NP101 to find out for sure. 


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#36 Mike W

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Posted 12 February 2019 - 02:29 PM

Except for low power sweeping, I found the TV Gibraltar wasn’t enough mount/tripod to support my TV NP101. The NP101 was rock solid on my DM6 Mount/tripod, but the combo weighed about 50#.

 

From these experiences, think the DM4 that I own now would be about right for the NP101, but I haven’t tried it. Tom Peters, owner of DiscMounts, says he considers a 4” refractor to be the sweet spot for the DM4, and we seem to have about the same tolerance of the shakes. Still looking for another NP101 to find out for sure. 

Which Gibraltar? The original Gibraltar with the larger altitude bearings or the current one with the Telepod head. That's what the current one is, an H/D Berlbach tripod with the Panoramic or Telepod head? Don't know why TV went this route? Here's a photo of the difference BTW the original Gib. is on the left and it handles my TV102 nicely.

IMG_4752.JPG


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#37 25585

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Posted 12 February 2019 - 04:58 PM

The basic mechanical components of the DSV-2 looks essentially identical to the Sky-Tee and the MG-2. I wonder if the Sky-Tee/MG-2 were copied from the DSV-2 or if they were/are manufactured by the same manufacturer?  Based on the Desert Sky Astro Products webpage, it looks like the former.  

 

Jon

For my other refractors I use a Skytee2. Its fine for 120s. I replaced the clamps. Its top mount is not stfong as its side one, but the latter is fine.

 

Skytee2 has slow motion cables, but fine adjustment of tensions, clutches, alignment is down to grub screws, and the stiction from thick white grease goo in its bearings, especially in the cold. 

 

I like the extension pillar and it mounts on a SW EQ5 tripod base.



#38 NC Startrekker

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Posted 12 February 2019 - 08:32 PM

Except for low power sweeping, I found the TV Gibraltar wasn’t enough mount/tripod to support my TV NP101. The NP101 was rock solid on my DM6 Mount/tripod, but the combo weighed about 50#.

 

From these experiences, think the DM4 that I own now would be about right for the NP101, but I haven’t tried it. Tom Peters, owner of DiscMounts, says he considers a 4” refractor to be the sweet spot for the DM4, and we seem to have about the same tolerance of the shakes. Still looking for another NP101 to find out for sure. 

The DM-4 is an exceptional match for the NP-101. In fact, it is overkill if there is such a thing when it comes to mounts. The DM-4 also pairs well with my SV-115T.  It will support my NP-127 competently but heavy eyepiece swaps becomes the rub. When swapping out heavy Ethos eyepieces, the altitude bearing is not quite large enough to produce the friction necessary to keep the scope from drifting. This led me recently to purchase a DM-6. It's rock solid now but at the price of a much heavier mount. Like refractors, mounts do not tend to scale gracefully either. But, I digress. If you get the chance to try your DM-4 with an NP-101, you won't be disappointed. 


Edited by NC Startrekker, 13 February 2019 - 09:40 AM.

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#39 nicknacknock

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Posted 13 February 2019 - 05:53 AM

DM-4 is a solid choice for this scope, but you need a solid tripod - it ain't just the mount. I even tested mine with my FS-128 and it could actually handle it (but with tight friction to hold it, still eminently usable). Tom Peters (owner of Discmounts) prefers to mount his AP130 on a DM-4 if that says something.

 

Another option is the AYO II mount from AOKSwiss. Dual mounting off the shelf (a plus relative to the DM-4) plus ability to include encoders (also available on DM-4). I have the AYO DIGI II mount for my FS-128 and it just laughs at the scope!

 

If you do go for the DM-4, do get the pan handle and also the eyepiece tray. Both make life much easier!


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#40 gwlee

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Posted 13 February 2019 - 01:14 PM

Which Gibraltar? The original Gibraltar with the larger altitude bearings or the current one with the Telepod head. That's what the current one is, an H/D Berlbach tripod with the Panoramic or Telepod head? Don't know why TV went this route? Here's a photo of the difference BTW the original Gib. is on the left and it handles my TV102 nicely.

attachicon.gif IMG_4752.JPG

Original with ash tripod. From talking to TV staff, gather the mount was designed to be used with TV 85. Understand that TV makes a heavier version of the Gibraltar now that was designed for the 5” TV refractor, which might be a better choice for the NP101. 

 

Regardless, it didn’t come close to meeting my expectations of an adequate mount for the NP101, but other people seem to like it. I thought it was a good looking mount, and it worked OK for low power scanning with the NP101. 


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#41 Jon Isaacs

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Posted 13 February 2019 - 01:21 PM

Original with ash tripod. From talking to TV staff, gather the mount was designed to be used with TV 85. Understand that TV makes a heavier version of the Gibraltar now that was designed for the 5” TV refractor, which might be a better choice for the NP101. 

 

Regardless, it didn’t come close to meeting my expectations of an adequate mount for the NP101, but other people seem to like it. I thought it was a good looking mount, and it worked OK for low power scanning with the NP101. 

Gary:

 

The SV-MG2 weighs 19 pounds and the NP-101 (with diagonal, clamshell) weighs 12 pounds, the rig, ready to go, weighs about 31 pounds.

 

Jon



#42 Mike W

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Posted 13 February 2019 - 01:31 PM

Original with ash tripod. From talking to TV staff, gather the mount was designed to be used with TV 85. Understand that TV makes a heavier version of the Gibraltar now that was designed for the 5” TV refractor, which might be a better choice for the NP101. 

 

Regardless, it didn’t come close to meeting my expectations of an adequate mount for the NP101, but other people seem to like it. I thought it was a good looking mount, and it worked OK for low power scanning with the NP101. 

Hard to believe since the TV85 wasn't even out when the original Gibraltar was in production!


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#43 gwlee

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Posted 13 February 2019 - 02:24 PM

DM-4 is a solid choice for this scope, but you need a solid tripod - it ain't just the mount. I even tested mine with my FS-128 and it could actually handle it (but with tight friction to hold it, still eminently usable). Tom Peters (owner of Discmounts) prefers to mount his AP130 on a DM-4 if that says something.

 

Another option is the AYO II mount from AOKSwiss. Dual mounting off the shelf (a plus relative to the DM-4) plus ability to include encoders (also available on DM-4). I have the AYO DIGI II mount for my FS-128 and it just laughs at the scope!

 

If you do go for the DM-4, do get the pan handle and also the eyepiece tray. Both make life much easier!

Tom gently tried to discourage me from ordering the pan handle with my DM4, but I bought it anyway because it worked well with my previously owned DM6 that I used with a previously owned NP101 and Mewlon 210. I am still searching for another NP101 or other 4” refractor to use with the DM4.

 

In the meantime, which is over a year now, I have been using the DM4 with my AT72EDii. I don’t like using the pan handle with this scope because it’s awkward, it’s heavy, and it exacerbates a balance problem with this tail-heavy refractor, so I have removed it. Tom suggested shortening the handle, but I haven’t done so yet because I want to try it with a 4” scope first. Don’t know how this will play out yet, but suspect I will eventually cut down the DM handle or sell it and fabricate my own handle because I have some concerns about steering a refractor by its diagonal. 

 

I bought the eyepiece tray with my DM6, but didn’t with my DM4 because I don’t want the added weight of the tray on what I hope will be a grab-and-go 4-inch refractor rig. Think I will eventually fabricate a smaller and lighter EP tray that I will mount on the tripod to lower the rigs CG. 



#44 gwlee

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Posted 13 February 2019 - 03:39 PM

Gary:

 

The SV-MG2 weighs 19 pounds and the NP-101 (with diagonal, clamshell) weighs 12 pounds, the rig, ready to go, weighs about 31 pounds.

 

Jon

Thanks Jon. I am budgeting 35# total for 4” refractor, mount, tripod, diagonal, EP, and finder, but it must be rock solid. Meeting weight is easy enough, but meeting weight with stability acceptable to me is much tougher. If I can’t meet both requirements with a 4-inch scope, I will go smaller. My experiments with the AT72EDII on the DM4 show it’s possible to get rock solid stability at 27#.

 

How much bigger I can go is unclear. I haven’t been able to find another NP101 yet, so I am tempted to buy one of the inexpensive Chinese 100mm f7 scopes to prove (or disprove) the concept before buying a premium 4” scope. I am stalling for the moment to see whether I get a call from AP about the new 92mm this Spring. 

 

Many of the currently availble mounts, including my DM4, require an extension column to allow pointing the scope at the zenith while staying clear of the tripod legs when scopes reach about 4 inches or so. The column adds about 3# to the rig. That’s also true of SV’s replacement for the MG2, which actually weighs a few pounds more than the weight specified on SV’s website, bringing it up to the actual weight of the DM4. 

 

Gary



#45 gwlee

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Posted 13 February 2019 - 05:10 PM

Hard to believe since the TV85 wasn't even out when the original Gibraltar was in production!

I wouldn’t know. Just relating what one TV employee told me when I was talking to him about the stability of the Gibraltar mount when used with the NP101. 



#46 Mike W

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Posted 13 February 2019 - 05:56 PM

I wouldn’t know. Just relating what one TV employee told me when I was talking to him about the stability of the Gibraltar mount when used with the NP101. 

The original Gibraltar was introduced 14 years before the TV85, all the scopes were 4" ( Renaissance, Genesis, Genesis SDF, and TV101) except the Oracle and the Gibraltar is way overkill for the Oracle. Just sayi'n, enjoy your DM


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#47 25585

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Posted 13 February 2019 - 06:26 PM

Hard to believe since the TV85 wasn't even out when the original Gibraltar was in production!

There was/is the Panoramic built for Renaissance and Genesis, kept for 85 and smaller. https://www.firstlig...ash-tripod.html

 

Then came Gibraltar 4, to take 101 and 102. https://www.widescre...k/G4M-6014.html

 

It was replaced by the 5 which was wider and taller to take NP127s. 

ehttps://www.widescre...k/G5M-5014.html



#48 Mike W

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Posted 13 February 2019 - 07:04 PM

There was/is the Panoramic built for Renaissance and Genesis, kept for 85 and smaller. https://www.firstlig...ash-tripod.html

 

Then came Gibraltar 4, to take 101 and 102. https://www.widescre...k/G4M-6014.html

 

It was replaced by the 5 which was wider and taller to take NP127s. 

ehttps://www.widescreen-centre.co.uk/G5M-5014.html

WHATTT!!!!!!!

Those are all current mounts, the original Gibraltar came out in 1984! 

Televue Renaissance 1984        Origional Gibraltar

"       "     Genesis           1988          "                "

"       "     "         "  SDF   1993          "                "

"       "     TV101& TV85  1998         "                "

"       "     TV101              2000     Current Gibraltar (HD4)

"       "      NP101             2001         "               "

"       "     NP101             2001


Edited by Mike W, 13 February 2019 - 07:41 PM.

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#49 terraclarke

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Posted 13 February 2019 - 07:11 PM

I wouldn’t know. Just relating what one TV employee told me when I was talking to him about the stability of the Gibraltar mount when used with the NP101.


When the TV85 first came out, it was paired with the Panoramic mount. I don’t know where the employee got his information but it's not what I remember at the time. Like Mike said, the Gibralter came out long before the lighter, smaller Panoramic. My older Gibralter head has significantly larger bearings than my Panoramic mount. The whole setup (mount and tripod) is a good deal heavier. I’m quite satisfied with its performance. The only thing I didn’t like about the design was bolting the clamshell of my Genesis SDF into the saddle when mounting the scope. I replaced the clamshell with Parallax rings and a mounting plate with permanent downward-facing mounting bolts threaded into the mounting plate. Now I just set the tube down on the saddle with the bolts going through the holes and then tighten the wingnuts. I put an ADM/Vixen mounting rail on the clamshell and use it when I put the Genesis on a GEM.

Edited by terraclarke, 13 February 2019 - 07:34 PM.

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#50 Mike W

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Posted 13 February 2019 - 07:21 PM

Thank you Terra! I understand why these guys want a different mount that will handle 300X but throwing around false information helps no one. It doesn't make sense that the Gibraltar came out 14 years before the TV85 but it was "made" for the TV85? What did they put on it? Did people buy  a Gibraltar and wait 14 years for the TV85?


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