troubles balancing takahashi

[Entropy]

Hey guys,
I recently purchased an fsq-106 to put on top my skywatcher EQ6. The mounting plate that came with it was no good so I purchased a losmandy dovetail which fits my mount. The screws that go in to the tube rings didn't fit the holes on the dovetail so I took some advise and drilled them out. Now the tube rings fit on the dovetail plate but the screws for the tube rings sit next to the actual dovetail so I can't move it up and down the mount to balance it. I have tried every combination of holes and tube rings with no luck, the telescope is always grossly out of balance (not even close). Any advice? I have a photo of the plate and rings if required, I'm just having some computer issues and can't upload it (also writing this message on my phone because of it)
Thank guys.

[pmrid (Peter)]

Entropy - seems a bit odd addressing someone that way but putting that aside - you have a mismatch happening between your rings and plate. I assume your plate is the wide Losmandy D standard as opposed to the narrower Vixen standard. Not all plates are created equal just as all tube rings - some adhere to metric and some to imperial measurements for the placement of mounting holes. Some tube rings have 3 holes that are an inch apart while others have 30mm separations. I suggest you measure your tube ring holes accurately and with that information, give Ron or Peter at Sirius Optics a ring and see which plate will work for you.
A hint - you don't really have to have a screw in each of the three holes in the rings - you could, for example, have one screw in the centre hole only and as long as it is done up reasonably tight, you'll probably be quite secure that way.
A photo of your 'problem' might help.
Peter

[blink138 (Pat)]

my advice would be dont skimp on that OTA!
look at mating the two with an ADM or a robin cassady plate for sturdiness and get rid of the tube rings
many here would tell you to spend 5k on a mount and a couple on the OTA!
you have it the other way around
this is only my opinion.... just wait for others to respond
pat

[The Mekon (John Briggs)]

Two ways to balance: by dovetail or by tube rings. I always prefer the latter, ie to balance by sliding the tube up and down the tube rings. I like whatever mounting plate is fitted, to be in the middle of the dec axis. Only problem can be if you have widely spaced tube rings, there may not be enough travel to shift the tube. Solution is to mount with a shorter base plate or dovetail.

[Entropy]

Thank you all for your advice, I'll try and reply to all points raised.
Firstly, Peter, my apologies if I offended you. I assume that you were unhappy with my use of the word 'guys'. I assure you that I only used this an informal and non gender specific greeting and nothing more. There was no ill intent to writing that. But if I offended you or anyone else for that matter, I apologies.

I would like to add that everything I have done so far, I have done with advice from a reputable telescope store (Replacing the hockey puck thing from a Vixen style to a Losmandy style, drilling holes in the dovetail plate) Just so you know I am not going off half-cocked or anything.

Now, on to the topic. My computer is now working correctly so I can attach some images so you can visualise my problem.
http://imageshack.us/a/img585/2966/dovetail.jpg
As you can see from this photo the heads of the screws protrude quite far below the plate and sit very close to the actual dovetail. This makes balancing the telescope by sliding the plate within the mount impossible. I have tried every combination of holes and have even tried non-standard spacing of the tube rings with no luck.

http://imageshack.us/a/img826/8076/t...ewithrings.jpg

As you can see with this shot there is little to no room to slide the OTA with the tube rings, making balancing that way impossible. As mentioned previously, I have tried making the spacing between the tube rings shorter without any luck. For example If i have the tube rings at there shortest possible spacing, with the tube ring sitting right up to the dew shield and the hockey puck sitting right against the screws from the tube rings in the dovetail plate the telescope will still be front heavy. I am at a complete loss of how to proceed. I'm pretty sure I have tried everything I can without purchasing new equipment.

Lastly, Pat, I have done it all a bit back wards but I can assure you this is only a temporary solution and I will be buying a much higher quality mount in the near future. I only did it this way because I could not handle using my poorly figured, poorly aligned, poor quality, 15 year old, cheap 8" Newtonian any longer and have decided that all purchases made from now on are done with a 'no compromise' attitude. I was thinking of getting the EM400 but I have heard some bad things about Tak mounts so I am continuing to research.

Thank you all for your help and once again I am sorry if I offended anyone.

Entropy

[pmrid (Peter)]

Originally Posted by Entropy

Firstly, Peter, my apologies if I offended you. I assume that you were unhappy with my use of the word 'guys'.

Crikey, I'm not offended. I was amused by the Tag "Entropy" since I understand it to mean a tendency to move from order towards disorder. It sounded like the experience of entering through the door of my shed and mpving towards the rear.

I have a Tak FSQ85 and have had a 106. If using rings, I go for the widest possible spacing which meant sliding the dew shield as far out as it will go and putting one ring right behind it. The other one I put as far back towards the focuser as I can - that way, if there are screws protruding, I still have a fair amount of clear grip on the Losmandy plate for sliding up and down in the mount head.

The rings you have look like genuine Takahashi rings. My guess is they were designed for use with a Tak mount as well which may explain the screw spacings. I'll leave others who have Tak mounts to clarify this.

Since you're using a Skywatcher mount, you'll need to migrate to different rings or, as another comment here suggested, get one of those plates that are designed to accept Tak rings or the Tak clamshell.
I guess everyone has different preferences. I didn't like the clamshell and had a set of rings made for my Tak as quickly as I could.
Pter

[mithrandir (Andrew)]

Will this bar from Robin Casady suit you?

Or maybe one from ADM. They have Tak specific ones.

[rally]

Entropy,

You have one problem you have identified and I suspect you may also have a second problem you have not yet identified depending on the camera/filterwheel system you end up with and your mount or the new mount you are getting.

The FSQ106 is a very back heavy scope owing to the 4 element Petzval design.
As such, once you add a camera, rotator, possible OAG etc etc you will find this to be an extremely backheavy system - so you have to move the whole OTA very far forward on the saddle plate.

Adding a big camera and filter wheel results in large diameter mass on the back of the OTA and this will need some clearance between the OTA and the mount or saddle plate.

Most OTA rings off the shelf do not facilitate this level of clearance, so you need to make up your own OTA Ring spacer block
This fits between the OTA rings and the Dovetail
Typically about 25-30mm is required.

More often than not a front OTA counterweight is also required - this is not a small mass either !
This can be achieved by using a second dovetail plate in the same dovetail which has the weight attached to its underside.

But a lot depends on your configuration.

So to solve the first and the second problem, in one go, I suggest you make up your own spacer block and that will allow you to have two sets of holes - one that matches the ADM/Losmandy bolt hole spacing and the other set of holes to match the FSQ OTA rings.
If this isn't a problem with the EQ6 - it will be a problem with many other mounts (with larger camera/CFWs).

Otherwise you will need to countersink the bolt holes and use countersunk socketheads to get them out of the way.
But bear in mind just how far forward they will need to be when fully loaded first before you start drilling !

Rally

[Entropy]

Thanks everyone for your help.
After taking everybodies input and discussion with the seller I have purchased some Parallax Instrument tube rings... These, from what I can tell, will bolt straight on to my Losmandy dovetail without any more drilling required.

Thanks again

[Entropy]

Me again
So using the old balancing method (telescope parallel to the ground.. balanced, etc) I can now effectively balance my telescope in both RA and DEC.
However when the telescope and counter weight bar is parallel to the ground and I rotate it so it is so the telescope is pointing directly up the scope is heavily out of balance to the front again.
On my old newtonian I used to fix this by rotating the actualy tube to achieve balance in that orientation. How can I balance this out with a refractor (this is my first serious refractor I have owned)
I have a Tak FSQ106 with a 7x50 Finderscope and an Orion Short tube 80mm autoguider sitting on top the tube rings of the tak (on a vixen style bar)
Any ideas, is this where a space plate is needed so i can rotate the tube, this doesn't seem viable however due to the guidescope getting in the road of the finderscope?

Thanks again