Polar Alignment made simple!

[Mcphisto]

I came across this, and as I was always looking for a step by step guide to PA, I assume that someone else will be too. Hope it helps

http://stevebb.com/polar_alignment.html

[Digz]

Interesting read. Not sure about putting a compass directly on the mount as it the metal would surely affect the compass reading.

[WaveSoarer]

Thanks for posting this. I have the EQ5 and I don't normally worry about the DEC and RA scales (probably not accurate enough to be useful anyway, especially the sloppy RA scale). I expect that these could be set up after polar aligning and once you've found an object with known DEC and RA values.

[gooseholla]

Yeah, RA scales etc... are very inaccurate. I used to polar align, swing to m31 - fine, within a degree or so. Swing back to polaris.... woah!!! Where has it gone?!

[Qualia]

Nice link, Mcphisto. The CG-5 and I imagine the EQ-5 has a hole through the polar axis which can be used for Polar alignment in basic observing sessions and I think setting up like this will suffice so long as one is not doing imaging or observing a given object over a long period of time. Here is another site which I have found useful.

[Mcphisto]

Nice link, Mcphisto. The CG-5 and I imagine the EQ-5 has a hole through the polar axis which can be used for Polar alignment in basic observing sessions and I think setting up like this will suffice so long as one is not doing imaging or observing a given object over a long period of time. Here is another site which I have found useful.

Thats great. Thanks Qualia, I'll be reading up on that in work....providing I find the time

[Ouroboros]

Nice link, Mcphisto. The CG-5 and I imagine the EQ-5 has a hole through the polar axis which can be used for Polar alignment in basic observing sessions and I think setting up like this will suffice so long as one is not doing imaging or observing a given object over a long period of time. Here is another site which I have found useful.

That's the method I use with my EQ-5 mount. I've found it's good for astrophotography for about 30 second exposures, and 60 seconds if I get it more on the button. I seldom get those really round stars you see in guided pics though.

I'm thinking of upgrading my mount to enable guiding. Do you know if the intermediate polar alignment plus guiding is sufficient for astrophotography? Or is drift alignment still essential?

[kirkster501]

With my EQ5 I use a much simpler method and ignore the circles entirely. First, my reticule alignment is spot on and I spent a lot of time getting this perfect following the "TV aerial" method.

I simply make Polaris touch the circle in the Polarscope and make it look as close as I can as it does in the AP software . I then rotate RA a few times to ensure that the polarscope orbit circle stays exactly on Polaris as RA is turned. This proves that Polaris is circling the NCP. If the polar finder circle does not stay on Polaris throughput the entire RA revolution then you have not got Polaris matching the AP polarfinder software accurately enough. It seems to work spot on and only takes a few minutes. I get a bit confused with all this mucking about with the the setting circles.

Appreciate what others think of my "method"

Steve

[Tinker1947]

I came across this, and as I was always looking for a step by step guide to PA, I assume that someone else will be too. Hope it helps

http://stevebb.com/p..._alignment.html

Be careful using the method describe here while its works having the rear leg facing South brings a few problems, its harder to look through the Polar Scope, and the likely hood of the tripod falling in the North direction is very high, the leg should be set to face North so the counter weights are over it, and there's a gap at the read to sit in and adjust the mount for Polar Aligning....

[sologuitarist61]

Interesting read. Not sure about putting a compass directly on the mount as it the metal would surely affect the compass reading.

I must admit that I too use a compass to roughly north align the scope and haven't found any problems with magnetism from the metal in the mount at all.

[Mcphisto]

That's the method I use with my EQ-5 mount. I've found it's good for astrophotography for about 30 second exposures, and 60 seconds if I get it more on the button. I seldom get those really round stars you see in guided pics though.

I'm thinking of upgrading my mount to enable guiding. Do you know if the intermediate polar alignment plus guiding is sufficient for astrophotography? Or is drift alignment still essential?

Your asking the wrong guy, I have a eq3 which I've yet to use for AP (this winter), so not experienced enough sorry.

[WaveSoarer]

Steve,

I think that rotating RA, as you've described, ensures that the polar scope reticule is well centred on the axis of rotation of the RA axis. I don't think that it necessarily means that the Polaris will track round the circle on the reticule. I think that periodic checking during the observing session would be needed to confirm that the polar alignment is absolutely right. Still if the small target circle is placed over polaris, the mount is level and the graticule has been rotated to the right position (according to the polar finder software), then I think that you can't do much more than that.

Dave

[Digz]

I must admit that I too use a compass to roughly north align the scope and haven't found any problems with magnetism from the metal in the mount at all.

That's interesting to hear. I have a compass somewhere, I'll have to dig it out and see -D

[Ouroboros]

My EQ-5 affects my compass. I always put the compass on the ground directly beneath the mount, then stand back to roughly point the tripod north-south.

[michael.h.f.wilkinson]

For visual I never worry about accurate polar alignment, for planetary, getting the polar scope's centre cross-hair aligned on Polaris is good enough, for DSOs use the Vixen manual, which means you set sidereal time on the polar axis in a few simple steps, and get Polaris in a little circle just next to the cross-hairs in the polar scope. I have managed up to 15minutes unguided using a short telephoto, and even at 1260mm (prime focus with reducer) I hardly needed to correct manually for 15 minutes (during the one or two attempts of capturing M42 on slide film).

[kirkster501]

Still if the small target circle is placed over polaris, the mount is level and the graticule has been rotated to the right position (according to the polar finder software), then I think that you can't do much more than that.

Dave

Indeed, with the HEQ5 I am not that sure there is much more you *can* do !

How can you make sure that the little circle in the finder is actually in the position that Polaris is expected to be in by just using the dials on teh HEQ5? I see what you mean about the "only proof is accurtae reticlule calibration" to paraphrase you. The question is how accurate do I make my Polarfinder view look comparfed to the sofwtare.

I need to research this a bit more.

I find that my subs of three to five minutes are pretty good all the same. Occassionaly I get off-round stars but everyone gets that with the odd exposure - especially if not guiding (like me).

Steve

[michael.h.f.wilkinson]

You could refine a bit by drift aligning. Takes quite a bit of time. At very long tracking times I have noticed a bit of residual drift occasionally, but I suppose nothing that an auto-guider could not correct.

[Astrosurf]

I use this for my HEQ5 and it's excellent, but I don't know how it would be for your mount. http://www.astro-baby.com/HEQ5/HEQ5-1.htm

I rarely have bad alignment.

Alexxx

[daz]

Be careful using the method describe here while its works having the rear leg facing South brings a few problems, its harder to look through the Polar Scope, and the likely hood of the tripod falling in the North direction is very high, the leg should be set to face North so the counter weights are over it, and there's a gap at the read to sit in and adjust the mount for Polar Aligning....

I'd also question the level-ness (is that a word??) of the RA with the counter-weights still attached, won't take much to nudge it down...

[michael.h.f.wilkinson]

I always do the final alignment with the whole setup: scope, weights, finder (whacking big 16x70), diagonal, Panzerfaust (Nagler 31T5) or flip-mirror and camera. By swinging the scope to about declination 0, I get a good sighting through the polar scope, and do not foul the tripod with the scope. The position can look very odd indeed, but if the setup is properly balanced, you do not get any shifts afterwards.

[Mcphisto]

With my EQ5 I use a much simpler method and ignore the circles entirely. First, my reticule alignment is spot on and I spent a lot of time getting this perfect following the "TV aerial" method.

I simply make Polaris touch the circle in the Polarscope and make it look as close as I can as it does in the AP software . I then rotate RA a few times to ensure that the polarscope orbit circle stays exactly on Polaris as RA is turned. This proves that Polaris is circling the NCP. If the polar finder circle does not stay on Polaris throughput the entire RA revolution then you have not got Polaris matching the AP polarfinder software accurately enough. It seems to work spot on and only takes a few minutes. I get a bit confused with all this mucking about with the the setting circles.

Appreciate what others think of my "method"

Steve

Ah, I think I've found my mistake! I had Polaris bang on center of the crosshairs in my polarscope. I'll have to try your method, I use the gps gizmo too which helps.

It's slowly making sense now. But it was still good enough for observing, but hopefully now I'll get it bang on for AP too! Thanks!

[kirkster501]

Hi Mcphisto, "my"method works spot on (actually I think I independently discovered what loads of people do anyway ). But being the stickler I am for prescision I always like more refinement. Hence me folliowng the setting circles method on AstroBabys website. Took me a few hours to work this out still but I now have it down to a T. Its well worth the investment in time to thoroughly suss this out. You can do it in the living room to get the Polaris circle to match where it shoudl be in the Polarinder sofwtare.

[Mcphisto]

Hi Mcphisto, "my"method works spot on (actually I think I independently discovered what loads of people do anyway ). But being the stickler I am for prescision I always like more refinement. Hence me folliowng the setting circles method on AstroBabys website. Took me a few hours to work this out still but I now have it down to a T. Its well worth the investment in time to thoroughly suss this out. You can do it in the living room to get the Polaris circle to match where it shoudl be in the Polarinder sofwtare.

I may try this tonight. I was going to take the scope out, but something's come up, so this may be a good idea for practice! Thanks a lot!!

[kirkster501]

The key is to know when a transit of Polaris has just happened or not - look at my thread on this over the last few days. I struggled at first but it call clicked after I realised i had been entering the wrong time.....

[Stargazer33]

Appreciate what others think of my "method"

Steve

Sounds interesting! When I finally get around to getting a polar scope for my new mount I will certainly be giving that one a go.

Bryan