How do I set up my telescope with a compass?
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- Joined: Thu May 26, 2005 10:18 pm
How do I set up my telescope with a compass?
Greetings,
I know some of you regularly set up your telescopes in the daytime using a compass. I need to know the number of degrees to point my scope off the north setting of the compass. For ease of use I'll set my compass to point at 360 degrees north. What would the heading be for Polaris?
Thanks for your help.
Clear skies,
Dan
I know some of you regularly set up your telescopes in the daytime using a compass. I need to know the number of degrees to point my scope off the north setting of the compass. For ease of use I'll set my compass to point at 360 degrees north. What would the heading be for Polaris?
Thanks for your help.
Clear skies,
Dan
Hi Dan,
Any decent topo map will tell you exactly but I use True North being 16 degrees East of Magnetic North. This makes sense as Magnetic North is actually somewhere in northern Canada so from our New England perspective MN is not as "high" up on the globe as TN, or, 'further East'.
If you want to find the exact value, or for other places this is a great website:
http://www.ngdc.noaa.gov/seg/geomag/jsp/Declination.jsp
put in lat/lon or zip and it will give you exact declination
Any decent topo map will tell you exactly but I use True North being 16 degrees East of Magnetic North. This makes sense as Magnetic North is actually somewhere in northern Canada so from our New England perspective MN is not as "high" up on the globe as TN, or, 'further East'.
If you want to find the exact value, or for other places this is a great website:
http://www.ngdc.noaa.gov/seg/geomag/jsp/Declination.jsp
put in lat/lon or zip and it will give you exact declination
Last edited by Bruce D on Sun Oct 22, 2006 3:54 pm, edited 1 time in total.
Bruce D
oh... I should have read your whole post more thouroughly...
Polaris will give you a much better approximation of True North than you will be able to get by trying to estimate 16 degrees on your compass (unless maybe you have a really expensive one!). The heading for Polaris is pretty darn close to 0, as it's less than 1 degree from True North.
I only use a compass if for some reason Polaris is obstructed (rare) or if I'm setting up in the daytime and can't see Polaris (more common since the club purchased the PST), you will want to use the compass meathod if you wnat to track the Sun for the upcoming Mercury transit
Polaris will give you a much better approximation of True North than you will be able to get by trying to estimate 16 degrees on your compass (unless maybe you have a really expensive one!). The heading for Polaris is pretty darn close to 0, as it's less than 1 degree from True North.
I only use a compass if for some reason Polaris is obstructed (rare) or if I'm setting up in the daytime and can't see Polaris (more common since the club purchased the PST), you will want to use the compass meathod if you wnat to track the Sun for the upcoming Mercury transit
Bruce D
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Bruce,
Thanks for the reply. I plan to set up the tripod during the day so it would be helpful to get it pointing towards Polaris as accurately as possible. My last trip to Vermont in September was pretty much a bust for using the Meade 5-inch ED. The two nights I tried to observe it was cloudy to the North. I couldn't use the GOTO as I could not see Polaris. I had to settle for views of whatever I star hopped to. I also used my Nikon 12x50 binoculars for some outstanding views in the parts of the sky without clouds. On the 2nd night I did dial in the GOTO after 11PM but clouds shut me down before 1AM. I'm hoping for better sky conditions this Wednesday and Thursday when I head back up there.
Clear skies,
Dan
Thanks for the reply. I plan to set up the tripod during the day so it would be helpful to get it pointing towards Polaris as accurately as possible. My last trip to Vermont in September was pretty much a bust for using the Meade 5-inch ED. The two nights I tried to observe it was cloudy to the North. I couldn't use the GOTO as I could not see Polaris. I had to settle for views of whatever I star hopped to. I also used my Nikon 12x50 binoculars for some outstanding views in the parts of the sky without clouds. On the 2nd night I did dial in the GOTO after 11PM but clouds shut me down before 1AM. I'm hoping for better sky conditions this Wednesday and Thursday when I head back up there.
Clear skies,
Dan
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- Posts: 524
- Joined: Thu May 26, 2005 10:18 pm
Bruce,
Funny you should mention putting up an observatory. While we were in Vermont in September Meredith asked about buying land near her sister's house in West Barnet. That's as far as it went, just talk. I don't have any plans to put up an observatory just yet. It would be nice but I don't have a location in my area. For now I'll enjoy the dark skies where I can find them, Westport and Rochester to name two of my favorites.
Clear skies,
Dan
P.S. Meredith was happy to donate the items.
Funny you should mention putting up an observatory. While we were in Vermont in September Meredith asked about buying land near her sister's house in West Barnet. That's as far as it went, just talk. I don't have any plans to put up an observatory just yet. It would be nice but I don't have a location in my area. For now I'll enjoy the dark skies where I can find them, Westport and Rochester to name two of my favorites.
Clear skies,
Dan
P.S. Meredith was happy to donate the items.
By the way, Dan and Bruce, Bruce's and my differences may be due to location, but Magnetic North is constantly moving and I use 15 degrees West as my offset. Check here for your magnetic north declination:
http://www.ngdc.noaa.gov/seg/geomag/jsp/Declination.jsp
http://www.ngdc.noaa.gov/seg/geomag/jsp/Declination.jsp
Galactus, Devourer of Worlds
AKA, George H
8" Meade LX90
66mm AT Guide Scope, cameras, etc.
25X100 Zhumell Binos w/Pete's Pipes
Bolt of Light Technologies Laser
Friends to observe with=Priceless
AKA, George H
8" Meade LX90
66mm AT Guide Scope, cameras, etc.
25X100 Zhumell Binos w/Pete's Pipes
Bolt of Light Technologies Laser
Friends to observe with=Priceless
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- Posts: 524
- Joined: Thu May 26, 2005 10:18 pm
Thanks Bruce I book marked that.bruce d wrote:Hi Dan,
Any decent topo map will tell you exactly but I use True North being 16 degrees East of Magnetic North. This makes sense as Magnetic North is actually somewhere in northern Canada so from our New England perspective MN is not as "high" up on the globe as TN, or, 'further East'.
If you want to find the exact value, or for other places this is a great website:
http://www.ngdc.noaa.gov/seg/geomag/jsp/Declination.jsp
put in lat/lon or zip and it will give you exact declination
Clear skies,
Mark
iOptron CEM25P w/ Tri-pier
CGEM DX
LXD750 w/ CDS #1697
LXD75 w/ #497 autostar Hypertuned
Antares 8" f/5 Newt
Antares 4" f/15 "Vixen Spec" long focus refractor
Orion 4" f/7 ED refractor
Astro-Tech 65mm Quad APO
and so much more
Mark
iOptron CEM25P w/ Tri-pier
CGEM DX
LXD750 w/ CDS #1697
LXD75 w/ #497 autostar Hypertuned
Antares 8" f/5 Newt
Antares 4" f/15 "Vixen Spec" long focus refractor
Orion 4" f/7 ED refractor
Astro-Tech 65mm Quad APO
and so much more