need help finding "North".

[messier 111]

hi all ,

I am trying to find out how to put my cg-4 in the right position.
I use a compass on my cel to put my mount as close to the celestial north.
from where I am it is impossible to see polaris.

my question is the following ,
I know that the compass on my cell tells me magnetic north.
how many degrees should I move my mount to arrive as close as possible to the celestial north?
and I guess I should move it to the left of my current position?

I hope I am clear enough and that I have chosen the right place for this thread.
as always thank you for your help.
Jean Yves .

[Bigzmey]

If this is for visual observing aiming at magnetic north is accurate enough.

[messier 111]

If this is for visual observing aiming at magnetic north is accurate enough.

oopsss
yes for the visual only.
I completely forgot to mention it.
thx.

[KathyNS]

Magnetic north will be close, but annoyingly far off, even for visual.

In Canada, true north varies from 20 degrees right to 20 degrees left of magnetic north, depending where you are. Google "magnetic variation" and the name of your town and you should find a reference for the number of degrees of difference. True north is left of magnetic north on the west coast, and right of magnetic north on the east coast. Around Winnipeg - Thunder Bay, the difference is close to zero.

Most phones should have a database built-in that will do the conversion for you. In fact double-check whether it is indeed showing magnetic north. It is more likely to show you its calculated version of true north.

[messier 111]

Magnetic north will be close, but annoyingly far off, even for visual.

In Canada, true north varies from 20 degrees right to 20 degrees left of magnetic north, depending where you are. Google "magnetic variation" and the name of your town and you should find a reference for the number of degrees of difference. True north is left of magnetic north on the west coast, and right of magnetic north on the east coast. Around Winnipeg - Thunder Bay, the difference is close to zero.

Most phones should have a database built-in that will do the conversion for you. In fact double-check whether it is indeed showing magnetic north. It is more likely to show you its calculated version of true north.

thx , i will look in to it .

[Gordon]

I have taken the liberty to move this topic to a different forum, hoping it will help new members. In addition, I have added to the subject title to help the search engines find it if someone is searching for it.

[messier 111]

I have taken the liberty to move this topic to a different forum, hoping it will help new members. In addition, I have added to the subject title to help the search engines find it if someone is searching for it.

Thanks Gordon,
I didn't know where to really put the tread.

[Makuser]

Hi Jean-Yves. I used this to mark celestial north for my location for my CG-4 mount. I went to this NOAA NCEI calculator web site:
https://www.ngdc.noaa.gov/geomag/calcul ... alc.shtml?
Using my latitude and longitude data from my iPhone compass, I entered these into the web site calculator boxes and the results came back that I have to add 7 degrees and 7 minutes to the right of my compass reading of the magnetic north reading at my location. I drew a line with chalk on my drive way for magnetic north then added the 7 degrees and 7 minutes to the right to resolve the correct path from the same starting point for celestial north. I then drew a perpendicular line across the celestial north line and placed the two rear tripod mount legs on this line. Last, I drew a ring around each tripod leg on the driveway with a red magic marker. Now I can set up my scope very quickly and it is pretty close. I hope this helps Jean-Yves and the best of wishes on your alignment project.

[JayTee]

All the smart phones that I have owned and used over the last 10 years, they're default position is to show you the true direction. So if it's pointing North that's where it thinks true north is.

[Makuser]

Thanks JT. I learned something new today. I just used my iPhone compass to get my location bearings and then used my hand compass outside to mark magnetic north and then make the change from the calculator web site to mark celestial north. I just compared my hand compass with my cell phone compass and I have to move the hand compass clockwise 7 degrees so they are parallel. You are correct JT and I never suspected this "auto" true north correction on my iPhone. Thanks, as this will save a lot of wasted time on future alignments.

[messier 111]

Thanks JT. I learned something new today. I just used my iPhone compass to get my location bearings and then used my hand compass outside to mark magnetic north and then make the change from the calculator web site to mark celestial north. I just compared my hand compass with my cell phone compass and I have to move the hand compass clockwise 7 degrees so they are parallel. You are correct JT and I never suspected this "auto" true north correction on my iPhone. Thanks, as this will save a lot of wasted time on future alignments.

plus one ,
I just saw that it works very well,
we're going to bed smarter tonight, thx.

[Makuser]

Here is a photo of my hand compass and iPhone compass comparison. Wow, this was a surprise for me to learn that the iPhone automatically converts to true north.

[Bigzmey]

I did not realize there could be that much deviation.

https://www.usgs.gov/educational-resour ... ue%20North.

But I am using phone app, not the old school compass, this explains it.