With my ED80 and ST80 on top as guide scope sitting as far forward as they can be on my HEQ5Pro mount, I can't achieve balance in DEC axis with my SLR and guide cam weight. RA balance seems fine. It's like I need more weight on the front end of scopes.
I have no idea what would be a good, recommended weight solution. What do you recommend? I was thinking, but maybe it's silly, was some of those velcro weights you can wrap around ankles for gym/running etc? Any better/cheaper ideas?
I bought an extension for the bar the carries the weight from Oneofone on this forum. worked a treat, and the price was very reasonable. Do a search for him and give him a call.
Oh, my post mustn't have been clear enough. It's not an issue with the weights for RA axis. It's DEC that's a problem. When I say I need to add weights to the front of my scope, I mean literally the scope, not the mount.
That must be easy.. Just wrap thick rubber around the tube (there are places selling various rubber product.. and rubber is pretty heawy).
Another alternative is to move the tube forward in the mount - it depends how the tube is attached to the Dec shaft.
Could you post some images of your scope?
I had similar problem with my dobson when camera is attached, and I solved it by adding brass weights (0.5kg) just under the mirror.
Also, I have a steel shaft (8mm dia) running in parallel with the tube, with movable weight (again, brass block). So I am ready for any eventuality :-)
Thanks Bojan. I've got the scope sitting as far forward in the rings as I can get it, and the dovetail is as far forward as it will go in the mount. Still not enough. Don't have any pics at the moment, but will take some at next opportunity.
I know what you mean Troy - I have the same problem.
At the moment I get around it by using a velcro strap and a 1.25kg dumbell from an old weight set. I use the velcro strap to strap the weight to the dew shield of the ED80.
Not ideal, and I'm following this thread with interest to find out how other people get around it.
Well if RA axis is not the problem maybe you should try mounting the guidscope side by side. I got a long dove tail bar and two dovetail mounts from bintel. All up it cost me about $100, plus it looks cool hehe. Go to bintel web page and look at "telescope Accesories" look for "Bintel Dovetail Mount (Vixen Style) " Two of those and cross bar and your set.
I picked up a couple of 500gm and 1kg scuba diving weights which I fix to various parts of my scopes, depending on what configurations I use.
As the weights are relatively light, I use Velcro and I also painted the weights with a couple of coats of black paint to minimise lead handling issues, using lead free paint of course!
These weights are cast such that you can thread a nylon webbed belt through them, so adding some Velcro to the nylon webbing and perhaps a thin foam backing to each weight (to protect the OTA) might just do the job?
This also gives you the flexibility to add/remove weights as well as some control over where they are positioned.
I was refering to Troy as he said his ST80 sits on top of his ED80, but your saying that yours is side by side so obviousely it wont work for him either.
Wow, how heavy is an ed80, I have an 8" newt with dslr and an st80 with a DSI II and manage to balance it perfectly side by side. Ah, but then I'm able to slide my newt up and down the rings for balance I imagine that you can do that with somthing as short as an ED 80. The penny drops.
Quote:
Originally Posted by iceman
Mine is a side-by-side setup. that's not the issue.
When you attach a DSLR to the end of the ED80, it puts a lot of weight at one end which swings easily unbalanced in the DEC axis.
Something is needed to balance the other end of the ED80 on the DEC axis.
On my dob, i use some magnets I got from a window washer, you know the ones do both sides of the window at the same time and an old socket set. I wrapped the square magents in white gaff tape so as not to scratch the scope. If i need more weight I add a nother socket/wratchet. Does the job nicely and you can be really precise with it because the sockets come in different sizes.
Have you got a shot of your setup as it is. I am thinking that the whole assembly must come forward. This will depend on your dovetail length which probably is a shorter version. So an image will give me some ability to give you advice. Adding weights is not the best way of going about this problem. Shifting the center of gravity is what you need to do. It will provide less torque on the tube of your telescope too.
Paul - I don't have a shot of setup at the moment. Will try to take some pics on weekend. The dovetail is pretty short, maybe 300mm long, as it's only for a 600mm ED80.
Troy, from my understanding, the eyepiece end is heavier than the objective end, and you have moved the scope as far forward as possible, Yes?
If so, buy from Bintel, (or somewhere) a dovetail mount like the one shown in the link for about $49.
Attach a lead weight as suggested by Dennis, by screwing it to the underside of the mount with some countersunk self tappers. Then attach the dovetail mount, c/w lead weight, to the existing dovetail, and that will slide along the length of the scope. Fine adjustment should be pretty easy.
If I've got it all wrong, sorry, if not, then your problem should be solved, and it should look reasonably neat.
Hi Troy
Here's another one for you...I had a problem with my 10" dob needing some extra weight down the mirror end so I filled up a length of clear plastic tubing (garden section..Bunnings) with fishing sinkers and some sand..blocked the ends with some corks and threaded a length of bungee cord through each end enough to provide a firm fit around the tube.
Cheers!
I had a similar problem when I first got my ED80 (in combination with a piggy back guide scope).
I solved the problem by simply mounting the guide scope a little further forward on the piggy-back dovetail bar (with the guide scope rings pretty close together ... only 100mm spacing).
Now balances fine in decl with flattener, DLSR, guide camera, etc.
Troy, from my understanding, the eyepiece end is heavier than the objective end, and you have moved the scope as far forward as possible, Yes?
Just to throw in a small variant on this interesting theme - I have an equatorially mounted newtonian, an 8" with a guidescope piggy-backed onto the rings for the main scope. It is mounted on an EQ6 Pro. When you go through the usual horizontal RA then horizontal Dec routine of balancing, it all balances well enough in both axes but when you put it back in the polar home position and release the Dec lock, the eyepiece (secondary) end wants to swing down to the left. This happens whether I have a DSLR in place or not. If I slide the scope back down the rings, the weight distribution is all wrong. I'm reluctant to add too much more weight onto the scope generally because I want to operate the EQ6 well within it's weight limits and I am now running at about 14kg which is where I want to be.
Any similar experiences, suggestions, solutions?
