Accurate Polar alignment with RA and polar scope help

[milan]

Having done a simple polar align last night (first time ever) by placing the EQ6 down and placing polaris in the circle i thought i would have a look at how you do it more accurately.

So having found a good link on here:

Polar Alignment with HEQ5 and EQ6 Mounts

i decided to have a play in the comfort of our house. Anyway got confused as the link says the lower numbers on the RA should be used for the northern hemisphere but the manual says that the upper number are for the northern hemisphere.

Can someone please let me know which it is?

Anyway which ever it was when i got onto section 4 of the link above polaris wasnt at the bottom as shown in Figure 12. Im 100% sure i followed the preceeding instructions to the letter so am a little confused!

Thanks

[dark knight]

Hi Milan, I believe it is the upper numbers on the RA scale for Northern hemisphere.

Polaris is not true celestial north and so still rotates around a point in the sky. Does your polar scope have any constellations in the eye piece, if so rotate the polar scope so the constellations match the orientatation of those in the sky, then adjust mount so Polaris is in the little offset circle. A very brief and simple example I know, but I'm sure someone will be along shortly with a thorough explanation.

Carl

[alfingido]

In red at the top it says..." lease note that Synta have produced at least two versions of the EQ6 mount and there have been variations in the arrangement of the RA axis markings. These instructions apply to the black bodied EQ6 with an RA setting circle with the top row of numbers graduated from 0 to 23 ascending in a CLOCKWISE (left to right) direction. If your EQ6 mount has a different setting circle, use the numbers that ascend from 0 to 23 in a CLOCKWISE irrespective of whether they appear on the bottom or top row of the setting circle.

"

Does this help? Those instructions are very confusing, it may be an idea to look somewhere else for a clearer explanation. See if this http://www.astro-baby.com/HEQ5/HEQ5-1.htm makes any more sense.

Allan

[Aza]

I always do my polar alignment with this method:

Tim Tasto Deep Space Imaging and Astrophotography

Works well

[milan]

We have the white EQ6 mount and when set to zero on the index marker the top row of numbers reads 1 to the right and 23 to the left. So RA marker do we have? Think that ties in with alfingido's explanation.

When you say clockwise i presume clockwise if you were looking through the polar scope?

[milan]

Well tried the site above and the manual and totally confused. Setup the date on the polar scope, adjusted the time on the RA index and then rotated around the RA Axis so the scale was on zero and UMa was over on the right in the polar scope where as it should be on the left (i used yesterdays date)

Any further advice?!?

[alfingido]

Ive never tried to set the date, but might have a go later. Which " above " site instructions did you try?

Allan

[alfingido]

I just tried Astro Baby's instructions ( link in my first post on this thread ) and it worked perfectly.

Transit time for Polaris at my location ( 51 21n 001 03 E ) is 04:57 on 14/09/2009 according to Starmap Pro.

I suggest you follow those and leave the manual alone.

Allan

[milan]

Okay will give it a try tomorrow. When aligning my understanding is that you set the date on the polar scope and then adjust (actually move) the RA scale to the correct time. is that right?

We have starmap Pro where is the option for the transit time of polaris?

Thanks

[alfingido]

When aligning my understanding is that you set the date on the polar scope and then adjust (actually move) the RA scale to the correct time. is that right?

Thanks

No, rotate the mount RA axis looking thru the polar scope till the small circle marked Polaris is at the bottom of the reticule and lock the RA axis, then lock the RA scale to 0, you leave it there and adjust the date scale till the correct date lines up with the transit time on the RA scale. So, on my scale, I lined up the mark for 14th Sept on the date scale with 04.57 on the RA scale ( or 5am, it was easier) Use the top scale that is on the RA ring or the one that counts up anticlockwise, ie, 0 at the top, 1 to the left, etc.

Then loosen the small screw on the black ring with the white date index mark on and line it up with 0 on the date scale. Your done!

Allan

[milan]

Thanks understand all that and according to your instructions i need to use the bottom set of RA numbers (1 is to the left), how do i then use that information (using your data above (14th Sept @ 04.57)) to align Polaris at 10pm, the evening before (13th Sept) i.e. the time that i was actually viewing.

Also given that we have the 'goto' version do we need to worry about this? Although it would like to understand how to do it manually

Thanks

[milan]

Hang on a minute am i getting myself in a real pickle here? having just read a thread in the beginners forum, once you set the RA ring on the RA axis and date on the polar scope for Polaris (as outlined in alfingido's post above) do you only use it to effectively find other stars? i.e. its nothing to do with locating polaris in the polar scope on a given date?

Can i just say AAAGHHHH!

[alfingido]

What you are doing is polar aligning the mount, you are not aligning it to Polaris, you are aligning it to the NCP using Polaris as a guide. That way, you will get no star trails when you use long exposures on photography.

You only need to do a rough alignment if you are visually observing or using GOTO as you adjust the accuracy of the pointing as you carry out the alignment procedure.

Allan

[steppenwolf]

Does this help? Those instructions are very confusing, it may be an idea to look somewhere else for a clearer explanation. See if this Astro Babys HEQ5 Polar Alignment makes any more sense.

I wrote the article in question and have had numerous thank you emails from people who have used my instructions to good effect - even Astro-baby acknowledges my contribution in her own article!

The contents of the article have served me and many others well for several years so I guess it can't be that confusing......

[milan]

Dont wory im still getting used to having a GEM as ive only used a Alt/Azt mount previously so its probably just me.

Having said that i think i have finally managed to get it sorted. It was setting the polar scope index line to the right position that was causing me all the trouble.

[milan]

I wrote the article in question and have had numerous thank you emails from people who have used my instructions to good effect - even Astro-baby acknowledges my contribution in her own article!

The contents of the article have served me and many others well for several years so I guess it can't be that confusing......

Now i sort of know what im doing ive just re-tried your method and twigged where i went wrong. Having a mac i didnt bother downloading the polar finder programme you reference so just followed the transit time on your example. Hence my confusion when i entered the date and found UMa and Cassopeia totally in the wrong place!.

You get another thanks from me

[steppenwolf]

My pleasure! That polar finder software is really useful isn't it?

[milan]

Didnt use that as we have a mac. (link timed out also) So i used Starmap Pro to get the transit time for this morning.