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If you want an equatorial mount for AP, the majority will recommend a suitably stout GEM.

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P.s. The scope will be used for astrophotography.
Cheers, Angus

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Fork mounts have a few advantages over a GEM for imaging. The most important being you can image through the meridian without the need to do a meridian "flip". OK. So, that's the only real advantage I can think of. A GEM will be more versatile in that you can use several different OTA's. Easier polar alignment. Easier to balance without the cost of buying additional systems. No need to buy an expensive wedge. No worries that your imaging equipment will swing through the forks. No worries about the forks flexing at lower latitudes.

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The most important being you can image through the meridian without the need to do a meridian "flip".

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The most important being you can image through the meridian without the need to do a meridian "flip".

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Actually... Both my Tak EM-200 and AP 1200 image right though the meridian without any flipping. I almost always cross the meridian while imaging - that's where the good stuff is!

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But you can't go horizon-to-horizon. It doesn't matter whether you flip an hour before or an hour after meridian - you still flip at some point.

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But you can't go horizon-to-horizon. It doesn't matter whether you flip an hour before or an hour after meridian - you still flip at some point.

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??? Of course you can. I've done it - sometimes because I fell asleep "at the wheel".

I don't know why everyone seems think you have to flip in the middle of an imaging run. Just not so... at least not with Tak and AP GEM's. If my cables where long enough, those mounts would do 360's.

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But you can't go horizon-to-horizon. It doesn't matter whether you flip an hour before or an hour after meridian - you still flip at some point.

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??? Of course you can. I've done it - sometimes because I fell asleep "at the wheel".

I don't know why everyone seems think you have to flip in the middle of an imaging run. Just not so... at least not with Tak and AP GEM's. If my cables where long enough, those mounts would do 360's.

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OK. I take it back. What I should have said is that I can't go horizon to horizon. As you mention, my Tak NJP doesn't know any better, and would cheerfully try - but it wouldn't do any good. I don't set up outside, so if the OTA is below the mount I'll be shooting images of the West wall long before I reach the horizon. At least, I would if I had installed cables sufficiently long to permit that kind of rotation, which I haven't. Frankly, I'm accustomed to using mounts that know better than to permit something like that to happen. The lack of safety provisions on the Tak is hardly a selling point. I put up with this lack because I like the mount otherwise.

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Please understand that my comments are in reference to the functionality of a GEM. They are NOT a comparison of Fork vs GEM. Quite frankly, I don't think the Fork vs GEM debate is a fair comparison. I don't know of anyone making fork mounts that are of the same quality as the top GEM vendors (Tak, AP, Paramount, etc).

You do not need a GEM for successful imaging - you need a very high quality mount of exceptional build. Right now, the only real offerings available to the amateur are GEM's. I'm quite certain that if someone started making/selling a fork mount that was of the same quality as a Tak, AP or Paramount there would be no "debate".

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Back in the 70's when I started into this hobby this was not even a debate.

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Yes, but back in the 60's I.... I forget. Having been in this "hobby" for almost 40 years, there's not much I haven't seen.

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But you can't go horizon-to-horizon. It doesn't matter whether you flip an hour before or an hour after meridian - you still flip at some point.

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??? Of course you can. I've done it - sometimes because I fell asleep "at the wheel".

I don't know why everyone seems think you have to flip in the middle of an imaging run. Just not so... at least not with Tak and AP GEM's. If my cables where long enough, those mounts would do 360's.

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Seriously??? I am looking for a high spec robotic-ish mount that doesn't need flips. Ive basically ruled out the Paramount. MI-500 or 750 fork (with TCS) is coming close, but if the AP1200 can actually do this..... Ive never heard this extreme before.. crikey

BTW the flips stuff up my photometry

Edited by gavinm (05/17/09 06:34 PM)

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