A Quick Way to Polar Align??

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This is intended for those who need, have to, to polar align via polarscope. Its with some apprehension I submit it but the reason I do is that - it works for me. So here it is. It begins with converting a 24hr HA to a 12hr HA (better precision) and concludes with the easy polar align. This is an extract from a 32 page booklet I am putting together for me (and newbies) to astro imaging. (Sorry, no web site)

Polar Align – Another Way

I am agog, yes, agog, at the polar align methods. Swing it in RA that way and then this. There must be another way. And so there is, I think, as below.

Firstly, I thought it would be easier to see Polaris on a normal 12 hour clock rather than 24hours. I did this in Excel and the HA time just needs to be entered and the calculation is instant. Take an HA off Eqmod – say 15h 40m 50s and convert that into decimal hours and the decimal day. Eqmod I believe accounts for precession.

Convert to decimal day = (15 + 40/60 + 50/(60x60))/24 = 15.678hrs/24 = 0.65day. Now bung that 0.65 into the following where D2 is the 0.65 day.

=IF(D2<0.5,(-0.5*D2+0.75)-0.5,(-0.5*D2+0.75))

= 10h 09m 35s

Polaris 12 hour clock position = 10h 09m 35s – double precision on a 24 hr clock. (Yes, its the same time as HA 15h 40m 50s)

Reprise. The Polaris little circle is a reference point only. You rotate the mount in RA to 6 oclock for the little circle. Setting circle to zero just there. HA high point. You then swing the mount again in RA so the setting circle HA time is against the index, tweak bolts and polar is done. It’s only a mechanical way of calculating Polaris little circle position. So all this swinging around is to get Polaris, little circle, at the right time! Why???

Now. This is the easy way and more accurate way. If the reticle is centred and you have Polaris in the polar scope, just tweak the bolts until Polaris is at its time on the bigger circle (using either the HA clock or my 12hr clock way). Polar align done! Forget where the little circle is – its irrelevant. No RA swinging. “I did it my way” several times and it works. And oh so easy. I have never seen this written and is probably not original - but it is for me. Try it out.

I hope that some if not all is helpful somewhere to someone.

I await in trepidation.