The 10Micron GM1000 HPS is an extremely popular mount. It combines the same high build quality and high precision features of the larger GM family of mounts, but in a smaller and lighter package making it ideal for those that want a portable set up.
If you have two telescopes, or if you have an imaging telescope and want to do autoguiding with an additional (guide) telescope, a side-by-side or parallel mounting is a popular way to configure these instruments. For that you would need a side-by-side mounting system or sometimes called an “H Bar” which consists of a dovetail bar with a dovetail clamp at each end.
10Micron offer their LoDual dual mounting dovetail bar and dovetail clamps to help with mounting two telescopes in parallel. The package consists of CNC machined components: a 400mm long Losmandy dovetail bar and two 200mm long dovetail clamps. The dovetail bar has a series of fixing holes that allow the clamps to have different spacing/separations – of approximately 210mm (8.3″), 245mm (9.6″) and 281mm (11”) – to accommodate different size optical tubes along with any protruding accessories (e.g. electronic focuser, finderscopes etc).
However, if you mount the LoDual mounting plate onto the GM1000’s (pre-installed) dovetail clamp, and then attach your telescopes, their orientation will be 90 degrees away/off from the fixed home position requirements of the mount.
In order to remedy this issue 10Micron offer a simple solution: a 90 degree changer plate kit. The kit consists of a short Losmandy dovetail bar onto which is attached a 200mm length Losmandy dovetail clamp (#1452085) which is fixed at 90 degrees to the length dimension of the dovetail bar (and thus GM1000’s clamp).
By attaching (clamping) this plate to the GM1000, the LoDual dual telescope bar and clamps (and thus the two telescopes) are now “rotated” by 90 degrees to ensure the correct orientation of the optical tubes (in order to comply with the fixed home position requirement of the mount).