[julianh72 (Julian)]

I've got a TwinStar-branded 90 mm Mak (FL 1200 mm / f/13.3) that I bought on eBay about 2 years ago for US$150 - I think the same telescope is available under quite a few brands. The key feature which distinguishes it is that it has a screw-threaded straight-through rear-port, and an internal flip-mirror to a second eye-piece port. I have bought a Mak-to-SCT adapter, so I can fit standard SCT accessories onto the rear port.

The telescope came with a 45° correct-image diagonal, so it makes a great terrestrial spotting scope. Replace the 45° diagonal with a 90° diagonal, and it's a very compact astro-scope.

The two ports are not par-focal (and not perfectly on-axis either - there's a bit of image shift when you flip from one port to the other), but I find I can fit a low power (eg 32mm Plossl) eyepiece in a short expansion tube in the flip-mirror port, and a higher power eyepiece and diagonal in the rear port, and then I have two almost par-focal eyepieces, which I find to be a great set-up for casual viewing. Enjoy the wider views in the 32 mm eyepiece, then flip to the higher power eyepiece, with just a small amount of fine focus required.

As a light-weight small-aperture scope, it is wonderful. The optics are absolutely pin-sharp and cool-down time is minimal. The supplied 8x21 finder scope is pretty useless, but I have replaced it with a red-dot finder, and that works much better. The supplied tripod is barely adequate even for low power, but it is now mounted on a more robust Alt-Az mount with slow-motion drives, and that works MUCH better for Astro viewing.

It is no match for my 200 mm SCT, but it's a great travel-scope, and I won't be selling it any time soon!