Preconceived notions

Getting an idea stuck in your head can sure cause trouble. 
For about a year I have owned an AT70ED. Right away I discovered that with my preferred mounting configuration it is difficult to balance the scope around its CG. Because of the notion that ‘the focusing knobs have to be level horizontally’ I came up with adding extra weight, one pound, forward of the vixen rail. 


Turned out, because I had installed a non-marking vixen clamp on my Sparta AZ mount, this configuration was a nightmare to work with. And it went counter to having a lightweight scope. So, finally started to question my idea that the focusing knobs just had to be level. And you know what? They don’t. So now I have a vixen rail long enough to balance the scope, and the standard and slow speed knobs pass under the rail. They only need to be about 15 degrees off level. 
​

And mounted it looks like this;

This set up worked with a minimum of fuss. And can even balance a heavy 2 inch diagonal and eyepiece. 
Hardly notice the position of the focusing knobs in operation. 
 

The white knob in the middle picture is a safety in case the vixen clamp isn’t tight enough, and allows the scope to slide back. (Which has happened but I caught it before it fell.)
Anyway, so much for ‘preconceived notions’. 

Edited by John R., 13 May 2024 - 11:32 AM.

John:

Focusing knobs do not need to be level but I like them to be level.. Sometimes, I cannot have everything I  want. 

Jon

Edited by betacygni, 13 May 2024 - 12:36 PM.

Another option is to swap the two speed from the right side to the left, I have done that a few times.  It's possible with some focusers but not all focusers.. It did that with this AT-72ED.

 

Jon

 

I found that in use, the tilt was hardly noticed. The problem with spacers is that the altitude bearing is already side loaded, and moving the CG out just increases the loading. When using an EQ mount in AZ mode, as Jon is in the photo, you can add a counter weight, but that provision is not available on any of my AZ mounts.  

All my AZ mounts are right hand mounted so turning the scope end over is not an option. Could rotate the focus knobs to on top I suppose. I have heard that the slow focus knob can be configured to the left side but I'm not going to mess with the mechanicals on an almost new telescope. 

I couldn't put my focuser "normal" or else I'd lose my panhandle.

mine fits better on my mount like Jon's

I could have done 15 degrees also I think, but I prefer it this way for my OCD

Edited by vicuna, 13 May 2024 - 03:44 PM.

Getting an idea stuck in your head can sure cause trouble. 
For about a year I have owned an AT70ED. Right away I discovered that with my preferred mounting configuration it is difficult to balance the scope around its CG. Because of the notion that ‘the focusing knobs have to be level horizontally’ I came up with adding extra weight, one pound, forward of the vixen rail. 
IMG_0206.jpeg

Turned out, because I had installed a non-marking vixen clamp on my Sparta AZ mount, this configuration was a nightmare to work with. And it went counter to having a lightweight scope. So, finally started to question my idea that the focusing knobs just had to be level. And you know what? They don’t. So now I have a vixen rail long enough to balance the scope, and the standard and slow speed knobs pass under the rail. They only need to be about 15 degrees off level. 
​ IMG_0235.jpeg

And mounted it looks like this;

IMG_0236.jpeg

This set up worked with a minimum of fuss. And can even balance a heavy 2 inch diagonal and eyepiece. 
Hardly notice the position of the focusing knobs in operation. 
 

The white knob in the middle picture is a safety in case the vixen clamp isn’t tight enough, and allows the scope to slide back. (Which has happened but I caught it before it fell.)
Anyway, so much for ‘preconceived notions’. 

I had to mount a C5 way off centre of a Orion VersaGo II alt-azimuth mount because it had a 2 inch diagonal on it. 

I am adding someone similar to the white knob you have on your dovetail to my dovetail plate. I just had the worst event with the dovetail slipping out of the saddle. Today I inspected it, there was a little bur on it that I hadnt noticed and I got some lubricant on the it from lubing the saddle screws that were sticking. I put my scope on the saddle and check it multiple times by even shaking it. I went inside the house to get eyepieces, walked up to the scope and suddenly like an avalanche it slid down. The dovetail hit my arm and punctured it, then dug in above my wrist, as the scope flipped i stuck out my foot and caught the objective end. The scope is fine.

Yikes! That must be a heavy scope. The little AT70 is only about 6 lbs. I observe sitting down. Had just swung the scope almost vertical and turned aside to pick up a different eyepiece when it suddenly slipped down almost into my lap. But mine never quite left the saddle. That's when I took it out and rigged the dovetail with that safety. I can slide it back to touching the saddle so if it loosens now, it can't go anywhere.  

I really like the clamp type saddles, don't care for screws digging into the aluminum rails, but didn't realize you must make doggone sure that clamp is really secure. 

Edited by John R., 13 May 2024 - 07:47 PM.

I couldn't put my focuser "normal" or else I'd lose my panhandle.

 

mine fits better on my mount like Jon's

 

I could have done 15 degrees also I think, but I prefer it this way for my OCD

Really nice looking mount! Afraid my Slik DX300 is not vibration free, but I like that I can adjust eyepiece height a moderate amount just be raising the center collum. If I move elevation a large amount then I go ahead and adjust the legs.   

Because the scope must be mounted left side & up for the computerized Sky-Watcher AZ-GTi, I used mounting blocks to get the scopes focuser horizontal and with room for my hand to operate it. It's a good arrangement and balances well IMO 

.

Because the scope must be mounted left side & up for the computerized Sky-Watcher AZ-GTi, I used mounting blocks to get the scopes focuser horizontal and with room for my hand to operate it. It's a good arrangement and balances well IMO 

 

rsz_1rsz_img_2067.jpg.

If that is an AT80ED then I have the same scope and mount, but haven’t mounted it on the GTi yet. Have to give it some thought now. 

John,...my AT80ED worked ok without the blocks but the fine focuser hit the pier extension or very close. So, the solution is to have the focuser in the vertical position. I got used to it but I was always fumbling around to find it in the dark. Also, know that the blocks work great as long as you keep the scope light. If you load it up with a 2" diagonal. heavy 2" eyepieces and a 9x50 RACI then you will need a much better tripod IMO. The AZ-GTI mount will handle the extra weight. no problem. Good Luck! 

John:

 

 

Focusing knobs do not need to be level but I like them to be level.. Sometimes, I cannot have everything I  want. 

 

 

 

 

Jon

Sorry but I’m waaaaay too Monkish (as in Adrian Monk, the great SF consulting detective) to EVER do that!  

Sorry but I’m waaaaay too Monkish (as in Adrian Monk, the great SF consulting detective) to EVER do that!  

John:

 

 

Focusing knobs do not need to be level but I like them to be level.. Sometimes, I cannot have everything I  want. 

 

 

 

 

Jon

I actually prefer it this way.   I like reaching directly under the eyepiece using it for (mental) alignment without having to look.  Once you get used to it, it's a hard habit to break. 

Getting an idea stuck in your head can sure cause trouble. 
For about a year I have owned an AT70ED. Right away I discovered that with my preferred mounting configuration it is difficult to balance the scope around its CG. Because of the notion that ‘the focusing knobs have to be level horizontally’ I came up with adding extra weight, one pound, forward of the vixen rail. 
 

I wanted my small ED refractors focusing knobs to remain horizontal as well, and they work just fine on a Sky-Watcher AZ Pronto ALt-Az mount.  Here is a slightly bulkier AT72EDII on it:

You can also add a long Vixen dovetail to the AT70ED:

The two smaller outer holes on the bottom of the AT70ED (and AT60ED) little mounting foot are 1/4"-20 threads that can be used with short 1/4"-20 screws to attach a Vixen/CG-5 dovetail rail.  You can also reverse the direction of the mounting foot so the scope can be moved farther forward to balance better with a 2" diagonal and a 2" eyepiece.

 

Another option is to swap the two speed from the right side to the left, I have done that a few times.  It's possible with some focusers but not all focusers.. It did that with this AT-72ED.

 

 

Jon

 

 

Good idea, Jon.  I tried it with an AT70ED, but the problem is that the holes that hold the bearings at each end of the focuser shaft are different sizes, and so are the bearings themselves if I remember correctly:

Edited by Oldfracguy, 14 May 2024 - 09:12 PM.

I wanted my small ED refractors focusing knobs to remain horizontal as well, and they work just fine on a Sky-Watcher AZ Pronto ALt-Az mount.  Here is a slightly bulkier AT72EDII on it:

 

101_2495.JPG

 

You can also add a long Vixen dovetail to the AT70ED:

 

101_1978.JPG

 

The two smaller outer holes on the bottom of the AT70ED (and AT60ED) little mounting foot are 1/4"-20 threads that can be used with short 1/4"-20 screws to attach a Vixen/CG-5 dovetail rail.  You can also reverse the direction of the mounting foot so the scope can be moved farther forward to balance better with a 2" diagonal and a 2" eyepiece.

 

 

 

 

Good idea, Jon.  I tried it with an AT70ED, but the problem is that the holes that hold the bearings at each end of the focuser shaft are different sizes, and so are the bearings themselves if I remember correctly:

 

101_1967.JPG

I have seen that type of AZ mount before but wouldn't that configuration be out of balance in most altitude positions. If possible, I prefer to have the altitude axis pass through the CG of the scope. Then, even when disengaged from the slow motion gearing it stays put in any position if balanced properly. 

On my AT70 those 1/4-20 threads are what I use to attach the vixen style rail. The Svbony branded 210mm long rail I bought from Amazon centered up, but just barely. The foot taps are 30mm apart on center and that is also the minimum distance apart cap screws can be with the rail center brace. Works anyway, even if not ideal. 

Edited by John R., 15 May 2024 - 12:58 AM.

I have seen that type of AZ mount before but wouldn't that configuration be out of balance in most altitude positions. If possible, I prefer to have the altitude axis pass through the CG of the scope. Then, even when disengaged from the slow motion gearing it stays put in any position if balanced properly. 

On my AT70 those 1/4-20 threads are what I use to attach the vixen style rail. The Svbony branded 210mm long rail I bought from Amazon centered up, but just barely. The foot taps are 30mm apart on center and that is also the minimum distance apart cap screws can be with the rail center brace. Works anyway, even if not ideal. 

Yes, it would be out of balance if you disengage the position gear clutch knobs.  I don't.  I just use the slow-motion gears to position the scope.  It takes a little longer, but it's a very small price to pay for the simplicity of this mount, and the fact that it can mount any type of scope with its dovetail rail on the bottom.  Besides that, the mount is strong enough to hold up scopes much larger than at AT70ED:

Here is a C6 SCT:

a William Optics Zenithstar 81:

and a 130mm f/5 Newtonian:

 

Another option is to swap the two speed from the right side to the left, I have done that a few times.  It's possible with some focusers but not all focusers.. It did that with this AT-72ED.

 

 

 

 

 

Jon

 

 

Never liked using Manfrotto heads to hold scopes.  They are too crude.  By that I mean sometimes it requires you use a lot of force to lock them in-place, even then they can slip.  I've got an old Leitz Tiltall tripod that is 1/2 the size (its head) compared to the Manfrotto and you can lock up to an 80mm scope with two fingers and it won't slip.  I put it all down to manufacturing tolerances.