Polar finder

[ultramol]

Can anyone tell me if the view in polarfinder is inverted or the right way up please, for instannce, if my reticule has polaris at the bottom is that what I look for in polarfinder or do I have to get a view where polaris is at the top then invert it. I am sorry if this makes no sense but I am a little confused...

[WaveSoarer]

You have the same telescope and mount as I have. The view that polarfinder gives will match the view you should aim to get through the polar scope: i.e. you should rotate RA so that the graticule is oriented in the same way as shown by polarfinder. If your graticule has casiopea and ursa major on it, which are both on the graticule of my polars scope, then these should be oriented to match the real sky. I hope this helps.

Incidentally, the polarfinder software allows you to set up the polar scope without having to worry about the setting circles. These are next to useless on the EQ5 - especially the atrocious RA scale.

[ultramol]

It does help alot, thank you very much...Regards  Geoff

[ultramol]

Sorry could you explain how to do it without using the RA circle which is as you say good for nothing on the eq5

[WaveSoarer]

I don't intend to be too negative about the setting circles as the EQ5 is a great mount. The DEC setting circle scale (the band with numbers) on my mount is nice and solid but the RA ring is just loose and wobbles. This initially had me worried when I first got the mount but, as I find objects just by star hopping, I don't actually use the setting circles anyway. There is an argument that the setting circles (the numbered scales) on this size of mount aren't of much value generally as the precision is insufficient to get you close enough to find most objects. If you can hop from one object to another then I find there is no need to refer to them. The mechanics of the mount is otherwise nice and solid so the motions of the RA and DEC axes very good indeed. It's just a little disspointing that SW didn't make a better quality setting circle scale for RA. Beware of the bendy altitude bolts also. I'm very careful with mine and I haven't had any issues as yet but I will eventually replace them.

For polar aligning I just used the method in my original post. First rotate the DEC axis so that the hole for the polar scope is open and then rotate the DEC axis so that the view in the polar scope matches what's indicated on polarfinder. It doesn't really matter what the setting circle scales are reading at this point if you're not intending to use them. Then just tweak the adjustment screws on the main mount (being careful to loosen one bolt before tightening the opposing bolt) until Polaris is in the little circle indicated on the graticule. Jobe done.

I usually do an accurate polar alignment, as I've described, with the scope and counter weights off the mount as this gives me free rotations of both DEC and RA without anything getting in the way. Once this is done I mount everything up. You can check the alignment again at this point but I have the the OTA horizontal, to both avoid clashing with anything or having the scope pointing at the ground (not a great idea to have the primary suspended above the secondary). The little circle for polaris wont be in the right place this time but that isn't importnat as its the position of polaris on the main circle around the central cross is all that really matters and you have the polarfinder software to indicate where polaris should be on this, the main, graticule circle. With the weight of the telescope etc on the mount you may find that you'll need to tweak the altitude bolts a little to compensate and bring polaris back on to the main graticule circle. That's pretty much it. To be super accurate you'll need to make sure that the mount is level (indicated by the round spirit level on the top of the tripod). I must admit that I don't check this much as the ground I put my scope on is fairly level and any small deviation in angle caused by the ground will be small in comparison to the uncertainty in the angle you'll set RA to when you're aligning on polaris.

One final thing is that you should check that the polar scope is properly aligned to RA itself. This can be done during the day by viewing a distance object through the polar scope. If you rotate RA then the cross at the centre of the graticule shouldn't move relative to the object you're pointing at. If it does then you'll need to tweak the alignment of the graticule using the three opposing grub screws that hold it in position. You need to be extremely careful doing the adjustment so that you don't strain the graticule. As for the altitude bolts, you'll need to loosen one - slightly- before gently nipping up - gently - one of the others. Do this by small incremental tweaks so that you move the graticule by tiny amounts at each itteration. There are tutorials on this alignment process on the web. Briefly though, align the polar scope on a small distant object with the empty counterweight bar placed vertically downwards. Then rotate DEC so that the bar is vertical and note the new position of the central cross on the graticule relative to the object (the original position). Now tweak the adjustment screws of the graticule in tiny steps until the cross is half way between the new position and the original position. Note this position and rotate DEC until the counterweight bar is pointing vertically downwards. If the cross moves again then tweak back half way and repeat until you get minimal movement. Then do the same with the bar horizontal and pointing to the left and then to the right - the cross shouldn't be moving much by then. In the end you're aiming to have the cross aligned on the same point in the distance no matter what orientation the DEC circle is in. This is quite tricky to do but once the polar scope is aligned to RA then you shouldn't need to revisit this.

[ultramol]

Wow,what can I say except thank you very much for your explanation on how to do it.  When I got my mount I checked that the reticule was in line optically and it was bang on. So now I only need to replicate what Polarfinder shows when I set up my mount at that particular time. Once again thank you for your trouble....Regards...Geoff