Gina

I think the confusion arises from the term TTL (Transistor-Transistor Logic) which used 0v and 3.3v as low and high logic levels. As I recall the average actual switching level was about 1.8v. Whilst TTL chips are still available they have generally been replaced by CMOS (Complementary Metal Oxide semiconductor) logic which has different specs. Although these devices still run on 5v (though they can run on higher voltages) the locic levels are 0v and 5v with the average switching level around 2.5v as I recall. Being not very different from TTL logic levels people tend to use the term TTL.

CMOS logic levels are 0v and Vcc (the supply voltage) with half that as the switching level generally. I like to run CMOS logic at 12v to give greater noise margins but if these mounts use 5v supply then you're stuck with a lower noise margin and using 3.3v rather than 5v makes things even worse.

Brilliant! Thank you I might even replace my HitecAstro EQDIR box with a nice short made up cable like that and save some mess on my mount.

Yers

I have a case ready to "pluck" but waiting for my Baader Hyperion zoom eyepiece to arrive. That should just about do it for a while

Gina, you ideally ought to centre the reticule in any polarscope-that way you can accurately align the the mount to the polar axis and hence get a more accurate polar alignment.

Ah I see. I thought the reticle would be set right why you buy the mount (costs enough) but perhaps I'm too naive

I'm puzzled... Why do you need to touch the polar scope reticle on an NEQ6?

Well, they use belts for driving the camshaft on cars these days and that is a pretty heavy duty.

Brill Thank you for posting

Gives me an idea for posting my webcam videos - I had forgotten about DropBox

I hope this thread and documentation helps others to go ahead with a worthwhile modification particularly to imagers who are always after that last bit of accuracy from their kit.

It is a very interesting thread and I have little doubt will be very helpful to me later with my imaging. So thank you very much for posting it

I may do that too, one day Ooooodles to do before I get to that stage!

There are 4... no 5 screens in this lounge The big monitor on this computer, another smaller one on the webcam PC, our Main TV and the CCTV monitor, currently watching the goat shed, making sure our young billy doesn't get through to to the young nannies out in the duck paddock, one of which is on heat! Then there's my netbook which I've been setting up for another webcam. Oh and there's an old laptop running my weather station software. That makes 6 then

Many of the tiny screwdriver sets come with two or three Allen key ends. I have one (more than one in fact).

I am finding all this interesting.

I liked fourier transforms at uni, very interesting.

Me too on both points Maths was one of my best subjects

While I'm no expert, it certainly seems to me from what you say Malcolm, that the ST80 is miss-aligned while the 200P is correctly polar aligned. So the ST80 is not exactly aligned with the 200P. I guess getting the two scopes exactly parallel would be quite difficult.

Hmm... I agree, it certainly looks like a "shrink fit". You might get away with heating the pinion as that looks like brass on a steel shaft. If I remember correctly, brass has a higher coefficient of expansion than steel. Of course, when assembled the steel shaft would be cold and the pinion would be heated then slipped on. Whether this would be a cheaper assembly method I'm not sure - saves the cost of drilling and tapping for a grub screw but requires much greater precision.

Oh to be young(ish) again Definitely feeling my age on this relatively heavy stuff. Replacing some of the wooden window frames on the house (next year) will be a doddle in comparison.

I agree too.

My word you didn't hang about!! Great stuff That design of yours was mainly what I based mine on. Good to see it "in the flesh"

Gina,

It's a 200P (8"), but on the HEQ5 it does seem to look a bit of beast !

Ah yes A bit smaller mount than mine, that's why it looks so big. I plan to get one of those scopes later when funds permit.

Tony, I have a small USB issue to resolve (seems common with the HP machine I use) and then I can start the alignment process and then see what all this autoguiding fuss is about

That will be interesting - I'm planning to do that later too. But I shall be trying a cheaper option than your guide scope - I have an M42 telephoto canera lens I used with my Pentax film SLR and the appropriate adapters.

WOW! Wonderful - I want wun! What size is that monster? I hope to upgrade sometime but it'll need a quite a while to save up the dosh!

Must say, I love your pier adapter Very nice looking setup.

Coming along nicely I like the sound of that flooring

Very good Just one small point - that roofing is designed to have the ridges in the direction of run off. With your orientation some rain water will be trapped behind the ridges and run of down the sides. Just something to bear in mind if you haven't already done so. Hope that helps

Gina, thanks. I've still got a few things to do, and there are a few things I want to change (like the main door)...

Yes, I see what you mean - it does rather let down an otherwise perfect looking shed.

but I am really pleased with the way it turned out. Just need lots of nice clear weekends now so I can have a lay in the morning after a nights observing

Absolutely

Looks really nice Malcolm and that obsy really looks "the business" :)

That's lovely Malcolm I'm glad for you both My OH is pretty good too, we get on well