Thanks Trevor ... looks like an effective and inexpensive setup.
Will follow your lead and try something similar on my HEQ5 rather than a piggy-back arrangement.
Now your cooking Trevor, nice work mate, it is amazing what one can make if one puts their mind to it, well done, and I'm sure it works a treat.
leon
Thanks Leon for the comment, the added holes along from the centre are so that I can change the center of gravity if need be. Theres room for a third scope in the middle however would need a bigger mount for that.
I found when a put the camera on the 80 things balanced up near perfectly although I haven't put my 60 finder on yet. I thought what I might do is also look at making some counter weights just in case.
I don't want to throw rain into the parade, but I would be worried about differential flexure in your system. I have suffered this with my own system, and the aluminium cross plate is around 13mm thick. Yours appears somewhat thinner.
At first I thought there was a problem with the guiding software, but I eventually tracked it down to flexure. The guide scope was working, and guiding, but the imaging scope was not keeping up, or getting ahead, or twisting to the side etc., with the affect of stretching the imaged stars in longer exposures.
Once I figured the problem out, by stiffening everything up, and careful balancing of the individual components, I reduced it to an acceptable level, but it is still a weakness that needs to be considered.
For anyone building a similar system, I would encourage making the cross plate as thick and stiff as possible.
HTH
BC
A standard vixen style dovetail bar say with a dimensions of 45 x 13 x 300 mm has 175500 cubic mm area whereas the plate I used dimensions are 400 x 150 x 5 mm has 300000 cubic mm of alum the stress is spread over a greater area
FWIW, I bought my system from Luke Bellami of StarStuff (via the Links on this site). The main bar is about 100mm wide by 13mm thick, and about 600mm long. He custom makes the attachment to the mount, and there are cross dovetails to allow adjustment in two planes to achieve fine balance.
BC
Thats seems very strange considering the volume and overall weight on the plate that you'd be getting flexing, it may be the grade alum he is using although I'm no engineer so your guess is as good as mine maybe we could get some feedback on this????
I was considering using a really hard wood (read: jarah) for this purpose rather than a aluminum plate, but weight is a concerning factor. I am a metal worker by trade however, Im sure I can get some good Alum to make the plate...
My original plan was to have a dovetail bar mounted to the bottom of a 10~15mm thick plate to attach to the mount, and two of the bintel female dovetail adapters at the ends as seen in your side by side setup.. however then I came to the realisation of weight... Im starting to think that having the guidescope set ontop of the main imaging scope may be the way to go...
Actually Alex In some ways I think you may be right for guidng purposes however for having two scopes or even three for visual observation or likewise having a set up that allows you to look while the camera's shooting away has it's attraction.
yeah... and mounting 3 vertically would not only be hard to achieve, but damn hard to balance I dare say...
I agree it has its attractions... when I did my first night of imaging the other night I was sitting there saying to my self... "I wish I could see M20 or M8 right now.... damn camera... always in the way..."