HEQ5 or alternative

[MarkH]

This thread is one of inexperience. I'm thinking of an eq mount but without tripod ascom comp. auto pec and easy alignment oh and not too expensive it's so dificult to find the right info from the net. Anybody got any good suggestions as to what is available in what format from whom?

[MarkH]

This thread is one of inexperience. I'm thinking of an eq mount but without tripod, ascom comp. auto pec and easy alignment oh and not too expensive it's so dificult to find the right info from the net. Anybody got any good suggestions as to what is available in what format from whom?

[Mike]

What are you going to use the mount for?

[MarkH]

Hi Mike, I was thinking of imaging. At the moment only 30 sec exp, but in future longer exp.

[Mike]

Then personally I would suggest nothing less than a H-EQ5. Anything below that is likely to be too wobbly and have a low load bearing capacity. Plus you need guiding ports and a handset port for GoTo (either with a handset or using eq-mod).

[The Thing]

I have successfully converted a Meade field tripod for my HEQ5 - much more stable than the little original one. It only needs a disc of ply the right thickness with a suitable hole in the middle, some M10 rod, nuts, washers and a metal rod for the azimuth adjusters to act on and some M6 bolts to bolt it in place through the AF threaded holes in the triopd head - easier than sourcing the correct bolts.

However Mark, you can get your current set up to guide adequately for imaging long exposures but you don't seem to have really given it a go...

[Mike]

Oh yeah, I forgot you have the wedge. Which means you've got everything you need to do long guided exposures.

[MarkH]

Thank you Mike and Duncan. You're quite right Duncan I haven't tried the wedge out properly yet and I do have a tendancy to get ahead of myself. My main concern was spending too large a proportion of my time on manual pec. Maybe I'll stick with it for now.

[Mike]

Don't bother with PEC. Just guide.

[MarkH]

Don't bother with PEC. Just guide.

What ? With a wedge ??? I thought correct polar alignment was of the essence, even with guiding a wedge ( excuse my ignorance and spelling)

[MarkH]

Sorry I have fixed in my head a really good idea of where the celestial pole is compared to polaris and referencing from cassiopia, but is that rough estimate good enough ?

[Mike]

Am I missing something. The wedge turns it into an equatorial mount right?

[The Thing]

With a Meade fork mount you set up the wedge on the tripod and then align the axis through the face you mount the scope base on to the celestial pole. I made a plywood ring to fit in the wedge hole with a hole in the middle which can be used to mount the finder scope to use as a polar scope, or you could use an actual polar alignment scope. AstroEngineering do the PolarMate for this purpose but its pricey at £122.

[MarkH]

That's a nice piece of kit Duncan, think I'll have to get one of those. I think I must have got the wrong end of the stick here, you are right Mike that's exactly what id does but I thought it had to be within a few arc minutes to get half decent results. 

[The Thing]

That's a nice piece of kit Duncan, think I'll have to get one of those. I think I must have got the wrong end of the stick here, you are right Mike that's exactly what id does but I thought it had to be within a few arc minutes to get half decent results. 

You shouldn't have any trouble getting accurate enough, look up Drift Aligning and also the various easily available tools e.g. Astrotortilla, PHD2 etc etc.

[MarkH]

This business really is the limit, total info overload. Right, now I have investigated I find that I mistook pec for drift   (shows how green I am  ) so I think that investing in your suggestion Duncan is the way forward. I know £122 but money well spent. I bet you lot all read this and think..."yeah I've been there" 

[MarkS]

I thought it had to be within a few arc minutes to get half decent results. 

In most cases, if you are aligned to within a degree of the celestial pole then that will be fine for a 5 minute exposure, as long as the guide star is within the Field Of View that you are imaging.  If you are doing longer exposures or your guide star is outside the FOV then greater accuracy is required.

I once did some maths to prove it - I must dig it out.