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How Do You Balance Your Small Refractor for Heavy Eyepieces?

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#126 desertlens

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Posted 13 December 2019 - 11:37 PM

I know you said you didn't want to stack dovetails but this works for me with the AT72EDII.

 

AT72EDII3.jpg

 

The short dovetail (Losmandy VUP4) has 2 1/4"-20 holes conveniently placed so that it can be attached to the rings first and the long dovetail is easily attached on top using these 2 holes. Be careful with screw length when attaching to the rings. The holes pass through the rings and a long screw can easily dimple the tube. The long bar easily clears the port side focuser knob. The mount is an SV M1V. The setup is nicely balanced as shown. Personally, I've never seen the attraction of tormenting a scope this size with a 2 pound eyepiece but this setup will allow you to get the mount pivot axis as far back as the focuser drive axis which should handle a lot of eyepiece in an already heavy focuser.


Edited by desertlens, 13 December 2019 - 11:45 PM.

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#127 Sarkikos

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Posted 14 December 2019 - 08:47 AM

Yes, it looks like the two-dovetail option will work pretty well as long as you minimize the length of the small dovetail.  But I'm already in it for the risers, which are purposely designed to solve the problem at hand.  A prime advantage to the risers is that they can lift the OTA higher above the dovetail than just the thickness of a second dovetail could.

 

Mike


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#128 desertlens

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Posted 14 December 2019 - 01:30 PM

The risers should be the best option. I just had the short bar on hand and was unaware if the Primaluce risers at the time.


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#129 sojourneyer

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Posted 20 December 2019 - 04:55 PM

Yes, this is an old and well-known story for observers with small scopes.

 

I have several small refractors for grab-n-go.  I mount them on a MicroStar Deluxe head on Vanguard Auctus Plus 324AT.  When I put a heavy eyepiece in the diagonal, the setup is out-of-balance and the telescope OTA tends to fall back, even when the altitude knob is clamped down hard.   The dovetail cannot be pushed far enough forward to compensate for the imbalance.

 

I don't want to replace the MicroStar and tripod with a more heavy-duty setup.  I have those options already, but I don't want to increase the size and weight for grab-n-go.  I'm looking for ways to improve the balance of the setup I already have.

 

Mike

Here is my simple solution. -  purchase a Velcro ankle bracelet and wrap it just behind the dewcap


Edited by sojourneyer, 20 December 2019 - 04:56 PM.


#130 sojourneyer

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Posted 20 December 2019 - 05:02 PM

On a TV 85, I "borrowed" one of my wife's one pound ankle weights, strap it around the OTA and slide it up or down the OTA as needed.  Works, easy, cheap.  It's made of a soft material so no problem scratching the OTA.

 

Dan

Also wrap a small bungee cord around the OTA with a small weight attached to the cord


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#131 sojourneyer

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Posted 20 December 2019 - 05:06 PM

Nope. No ankle weights.  No rubber bands.  No bungee cords.

 

Mike

It will be years before a bungee cord breaks.  Plus  inspection of the cord will tell you it needs replacement 



#132 Sarkikos

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Posted 20 December 2019 - 06:59 PM

I appreciate your ideas, but I want a solution that is a more permanent and integral part of the system.  Risers should do that nicely.  I can install them once and be done with it.

 

Mike


Edited by Sarkikos, 20 December 2019 - 06:59 PM.


#133 Sarkikos

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Posted 30 December 2019 - 10:23 AM

OK, so it's been nearly a month since I ordered the PrimaLuceLab 30mm PLUS Spacers from High Point Scientific (ordered 12-5-2019).  That same day I received an email from HPS saying the item was "currently on back order with an estimated in stock date of 7 to 14 business days."

 

I called HPS this morning.  The associate said that PrimaLuce is slow in shipping out any product, and that he had no idea when they would have more in stock.  So I cancelled the order.

 

Joseph07081 said in post # 117 that he received a tracking number for his PrimaLuce risers.  That was back on December 12th.  He ordered from Woodland Hills.

 

When I order again from a vendor, I'll call to make sure they actually have them in stock and that will send them to me at once.  No more waiting a month for something that never comes.

 

Mike



#134 Sarkikos

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Posted 30 December 2019 - 10:24 AM

Mike

I just received a tracking number for my spacers, perhaps some inventory is making it's way to dealers. 

Joseph, did you ever receive the risers?  If so, how did they work out for you?

 

Mike



#135 Sarkikos

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Posted 30 December 2019 - 12:50 PM

I just now called Woodland Hills.  Although their website says the Primaluce Labs 30mm spacers are in stock, they are not in stock.  And Woodland Hills has no idea when more will be available.  Though the 20mm and 10mm are in stock.  But they are not what I want, so I will not order them.

 

Well, I'll wait until they are available.  Or I'll try to find a reasonable substitute.  I really don't want to order straight out of Italy.  Although if nothing shows up here in the USA, I might have to. shrug.gif

 

In the meantime, I'll continue to use the counterweights.

 

What I will not do is rig up some rubber bands or bungee cords - or some other Rube Goldberg device - as a virtual counterbalance.  

 

https://www.google.c...iw=1920&bih=975

 

Mike


Edited by Sarkikos, 30 December 2019 - 12:59 PM.


#136 Sarkikos

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Posted 30 December 2019 - 01:15 PM

I called PrimaLuceLab USA.  They said they have about a dozen of the 30mm spacers in stock.  I placed my order.

 

https://primalucelab...mm-spacers.html

 

Mike


Edited by Sarkikos, 30 December 2019 - 01:15 PM.


#137 Sarkikos

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Posted 30 December 2019 - 01:21 PM

I checked the email receipt from PrimaLuceLab USA.  The payment is to Woodland Hills Camera & Telescopes.  Now, isn't this the same company who a few minutes ago said they didn't have the 30mm spacers in stock?  And yes, the receipt is for 30mm spacers, not 20mm or 10mm.   But the PrimaLuceLab USA website I ordered from is a different website from the Woodland Hills website.  Also, I did receive a second email receipt directly from PrimaLuceLab USA.  What gives?  

 

I hope the guy who answered the call for PrimaLuceLab USA didn't just glance at the product count on the website and assume it was correct. 

 

Mike


Edited by Sarkikos, 30 December 2019 - 01:30 PM.


#138 REC

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Posted 30 December 2019 - 02:11 PM

I use ankle weights and wrap them around the tube. Easy fix and no need move the tube ect.



#139 REC

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Posted 30 December 2019 - 02:13 PM

Also wrap a small bungee cord around the OTA with a small weight attached to the cord

Yup, me to, simple fix! Use it when I have a binoviewer on the back.



#140 Sarkikos

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Posted 30 December 2019 - 02:16 PM

No bungee cords, no ankle weights.  Now, I have gone over this before on this very thread.  poke.gif

 

Google "Rube Goldberg machine."

 

grin.gif

Mike


Edited by Sarkikos, 30 December 2019 - 02:17 PM.

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#141 Sarkikos

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Posted 30 December 2019 - 02:54 PM

Look back at my post # 86 to see the counterweights I use now.  They are easy to attach or remove as needed.  I can also move the dovetail adapter forward or backward on the dovetail to help balance the scope.

 

Mike


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#142 houndsbourgh

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Posted 10 February 2020 - 07:56 PM

Kind of a struggle to find room on my dovetail for my counter weight on different mounts. I needed something a bit more elegant and compact. I decided on a stackable system. Much like my old C90 Astro. Small Rig makes some very economical stackable weights for photography based on the 1/4-20 thread. 200, 100 and 50 gram are available. For the mount I made a 1/4-20 female/6mm male mounting ring stud. Neat and clean. And as far out on the dovetail as possible.

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Edited by houndsbourgh, 10 February 2020 - 09:39 PM.

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#143 joseph07081

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Posted 11 February 2020 - 11:25 PM

Joseph, did you ever receive the risers?  If so, how did they work out for you?

 

Mike

Mike

i am sorry, I lost track of this thread. I did receive the risers that I ordered and they worked out well. Unfortunately work and weather have kept me indoors since then. 



#144 Sarkikos

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Posted 12 February 2020 - 07:54 AM

Mike

i am sorry, I lost track of this thread. I did receive the risers that I ordered and they worked out well. Unfortunately work and weather have kept me indoors since then. 

Ditto for me.  I received the risers a month ago.  I ordered them directly from PRIMALUCELABUSA.COM.  They actually had the spacers in stock.

 

I have tried them on the AT72EDII and they work fine.  Also ditto for the work and weather.  My tests have only been inside, no field tests yet.

 

Mike



#145 k5apl

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Posted 15 February 2020 - 10:56 AM

I balance my scope with a magnet from Amazon and some hardware from Tractor Supply.  The pictures show the scope with a Morpheus 9mm eyepiece and a 19mm Pentax zoom eyepiece.  The scope is balanced with no pressure from the friction knobs.  This is easier for me than moving the scope in the rings or moving the dovetail in the dark.

(the magnet has a 1/4-20 stud that screws into a tapped hole in the dovetail).

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Edited by k5apl, 15 February 2020 - 12:21 PM.

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#146 Jon Isaacs

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Posted 15 February 2020 - 11:01 AM

Yes, that's why I didn't order the risers from Woodland Hills.  I think OPT also showed them in stock.  But those companies are in CA, at the other end of the country, and chances are the risers are not actually "in stock."  So I took my chances with HPS, which is close and ships fast.

 

Mike

 

I can tell this, if you'd called Woodland Hills and asked, they would have looked on the shelf to see..

 

Jon



#147 Sarkikos

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Posted 15 February 2020 - 03:48 PM

I can tell this, if you'd called Woodland Hills and asked, they would have looked on the shelf to see..

 

Jon

After waiting for several weeks for the risers from HPS, and not receiving them, I cancelled my order. 

 

Then I called Woodlands Hills to see if they had them in stock. Woodland Hills told me they did not have them in stock

 

Later that same day I called PrimaLuceLabsUSA, who said they had them in stock.  So I ordered from PrimaLuceLabsUSA and received the risers in a week or so.  This despite the fact that my payment to PrimaLuceLabsUSA went to Woodland Hills. shrug.gif

 

Someone else can figure it out.  I really don't care.  I have the risers now.

 

Mike


Edited by Sarkikos, 15 February 2020 - 03:52 PM.


#148 aa6ww

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Posted 16 February 2020 - 10:41 PM

Why not just use a longer dovetail bar. We all have extra dovetail bars. They come on and off in a minute and allows the entire scope to re balance easily.  Ive use this on my AT-92 with the barlow in front of the 2" diagonal with large 2" eyepieces, and their is plenty of room to always be in balance just by sliding the dovetail in the saddle. 

These are little lightweight scopes and require no effort to adjust the position of the scope.

 

 

...Ralph

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Edited by aa6ww, 16 February 2020 - 10:41 PM.


#149 areyoukiddingme

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Posted 17 February 2020 - 01:13 AM

I has a Half Hitch Mk 3 (from memory).

 

That mount was only balanced when it had an eyepiece in the scope, so it had two counter measures.

 

The first was a slotted attachment on the altitude with a 1.25" weight. The weight was screwed into the slot with a plastic washer, so a half turn or so, and it could be slid back and forth to move the center of gravity back and forth.

 

If that wasn't enough, the second counter measure was that that weight could have a 1.25" adapter slipped over the top. If you had a Televue Equilizer, that could be quite a bit of weight.

 

I got sick and tired of doing the swaps as I like using eyepieces of a range of weights.

 

Now I use a Stellarview M2, and it generally keeps good balance changing between eyepieces, and I can twist the tension on the altitude quickly if imbalance is an issue.


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#150 Redbetter

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Posted 17 February 2020 - 04:41 AM

Why not just use a longer dovetail bar. We all have extra dovetail bars. They come on and off in a minute and allows the entire scope to re balance easily.  Ive use this on my AT-92 with the barlow in front of the 2" diagonal with large 2" eyepieces, and their is plenty of room to always be in balance just by sliding the dovetail in the saddle. 

These are little lightweight scopes and require no effort to adjust the position of the scope.

 

I don't understand how the question relates to the development of the OP's request.  Ignoring the fact that we don't all have "extra dovetail bars" (mine are all accounted for on scopes), your image shows what appear to be risers, in addition to a very long dovetail bar (another item I don't have and I suspect that is somewhat uncommon thing for others as well.)   That looks like a reasonable solution for the longer/heavier objective AT92 triplet, but not necessarily the optimum for an AT72 doublet with a lighter objective and shorter lever arm.  

 

Part of what I gathered from the thread is that a 30mm spacer will allow the AT 72EDII's focuser knobs to clear in rotation.  That is a handy bit of information.   A second dovetail won't provide enough space to clear the knobs from what I see.  So purchasing a more expensive extra long dovetail to go with the shorter Vixen doesn't seem to be as full of a solution.  

 

At any rate, spacers and a moderately sized dovetail seem a far more elegant and simple solution to me.   Probably more cost effective too, especially since it is possible to fabricate custom spacers for a fraction of the cost.  


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