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michaelmorris

What's the best way to align mount north in daytime?

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I much prefer to get my tripod, mount and scope set up in good daylight so that I can hopefully maximise my time imaging. However, I often find that my initial stab at pointing the tripod facing north using a compass is often so far out that I end up having to move the tripod and mount with everything on it to get the mount close enough to north to then use the azimuth adjustment bolts to get it polar aligned.  This often then leads to the tripod not being level.

Is there anyway to get this initial rough alignment in daylight more accurate?

 

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Once you have it set up correctly, could you mark the positions of the tripod feet somehow (I know some people drill holes in the patio or whatever, but that may not always go down well) and then mark an index line across the mount and tripod head, so you can get the feet of the tripod in the right place and then align the mount to it?

I've never bothered with getting the tripod head level myself.

James

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Come to think of it... What method do you use for polar alignment?  It may well be that you could do that before it's sufficiently dark for imaging anyhow.

James

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I use a Wixey angle finder to get the Alt angle right and then I tend to use a compass.

I align the North arrow of the compass and rotate the body so the long edge is aligned E-W then I have a piece of string between the E and W legs of the tripod. Once the string is parallel to the side of the compass, its normally close enough for me, but I do visual only. 

This is a tip a saw on @Montana blog when I was searching how to polar align in daylight for solar observation.

I use this method in daytime and at night. I think I've only ever properly polar aligned my EQ5 once and found the process such a nuisance that I quickly looked for a lazy man's way to do it. 

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I have no view north so have to use Celestrons All Star Allignment anyway or drift with PHD2.

Once I finally got it right I put sharpie marks on the tripod rings and little dots on the ground. Its in the back yard so I got 3 large walkway stones and a couple bags of sand and leveled that first.

Now it’s usually only off by a small margin on initial setup but for daytime solar would be fine right away.

I did have major issues with my new mount that took 3 months to sort but thats a rant I’m not going to go into.

I’m guessing eventually the sand based blocks will shift and I’ll have to redo but I don’t want to cement them.

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3 hours ago, scrufy said:

 

I did have major issues with my new mount that took 3 months to sort but thats a rant I’m not going to go into.

Obviously a celestron if using the ASPA  routine....

If you want a good rant to get it off your chest, fire away.. I'd probably be nodding in agreement..

 

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4 hours ago, scrufy said:

Once I finally got it right I put sharpie marks on the tripod rings and little dots on the ground. Its in the back yard so I got 3 large walkway stones and a couple bags of sand and leveled that first.

Thanks.  However, my enquiry relates to setting up on a new site, not an existing site (something I didn't make clear in my original post).

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5 hours ago, AdeKing said:

I align the North arrow of the compass and rotate the body so the long edge is aligned E-W then I have a piece of string between the E and W legs of the tripod. Once the string is parallel to the side of the compass, its normally close enough for me, but I do visual only. 

This is a tip a saw on @Montana blog when I was searching how to polar align in daylight for solar observation.

Thanks. 

I can't find any blog entries for @Montana, do you have a link?

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I had the same issue with my Skywatcher tripod. So I made a simple guide assistant using three elastic bands and two pieces of string. Referring to the diagram below.  

First place your mount with the North Facing leg A of the tripod point roughly north. Using your compass.

Attach an elastic band to each of the three feet.  Fasten a piece of string to the elastic band on foot B and stretch the string across and attach to the elastic band on foot C making sure it is taught before fastening in a knot to the elastic band.

Then get a second piece of string and attach to the elastic band on foot A ( the one pointing north and pull this tight and fasten in a loop around the middle of the other string at point X.

You can measure with a tape measure the exact mid point of the string between B - C and mark it with a felt marker.  Then simply slide the other string so it joins at exactly this midpoint.

If everything is nice and taught then the string between A and X should point N -S. and can be used as your guide to get a more accurate North as you can move feet B and C left or right until that string lines up exactly with your compass.

 

Hope this makes sense.  It allows me to get within 1 - 2 degrees of accuracy.

 

 

Direction.thumb.jpg.05f07919400ddf732313f857e160b849.jpg

 

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Two tips that helped me:

  • the metal in the tripod can affect the compass so make sure it’s far enough away
  • adjust for difference between magnetic and true north which is about a degree for me

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13 hours ago, newbie alert said:

Obviously a celestron if using the ASPA  routine....

If you want a good rant to get it off your chest, fire away.. I'd probably be nodding in agreement..

 

Not really going to go there but I went from a very expensive but 20 year old mount to the CGX (which is still $2200 USD, and it took 3 months of support to even begin tracking. I still have backlash issues and am about to abandon the warranty and start tapping set screw holes to align the belts as they should have been if Celestron Engineers even slept in the back of the classes I was in.

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[EDIT]  No longer 5 degrees in southern UK - so not so important.

People should be aware that the magnetic north pole is about 5 degrees west of the true north pole.

 

 

Edited by don4l

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1 hour ago, don4l said:

People should be aware that the magnetic north pole is about 5 degrees west of the true north pole.

 

The magnetic declination will vary depending on your location, and any decent compass should be adjustable to take it into account (usually a tiny screw on the bezel)

Edit: in the UK (Greenwich) the declination looks to currently be about 8 minutes west, so not a huge difference

Edited by CraigT82

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1 hour ago, don4l said:

People should be aware that the magnetic north pole is about 5 degrees west of the true north pole.

 

It varies considerably by location and over time and is unlikely to be 5 degrees anywhere in the UK this year. Here's a link to the US/UK model for 2019:

https://www.ngdc.noaa.gov/geomag/WMM/data/WMM2015/WMM2015v2_D_MERC.pdf

As you can see, in the UK, the difference between true and magnetic north in 2019 is more likely to be in the range of 0 to 2 degrees for England and Wales and in the range 1 to 4 degrees for Scotland and 3 to 4 degrees for Northern Ireland.

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If you're planning setup on a new site, look up that location on google earth... go to a 3d type view and zoom right in on the patch you're planning to set up on.

Make sure the image is pointing n-s as google earth should always point to true north. Then use a very local landmark such as a tree or similar to get as close as reasonably possible before a quick drift alignment as soon as suitable stars start appearing.

Not perfect but should be reasonably practical and better than nothing.

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21 minutes ago, Jonk said:

If you're planning setup on a new site, look up that location on google earth... go to a 3d type view and zoom right in on the patch you're planning to set up on.

Make sure the image is pointing n-s as google earth should always point to true north. Then use a very local landmark such as a tree or similar to get as close as reasonably possible before a quick drift alignment as soon as suitable stars start appearing.

Not perfect but should be reasonably practical and better than nothing.

This does work quite well actually. I use google earth and I use the "draw line" feature to draw a line on the map with one end fixed at my observing location, and the other end at the north pole. Just so happens that the gable end of a house nearby falls exactly on the line and so I set the north leg pointing to that gable end. 

 

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The same method is used for satellite dish alignment.

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