Ironically, I find is soooo much easier to locate and identify the asterism of 4 stars that make up the Octans trapezium……in light polluted Brisbane, than I do at a dark sky site!
The light pollution in my suburb is optimised such that these 4 stars just peek out above the light pollution threshold, making them reasonably easy to see in my Polar Alignment Scope once I have acquired the general field.
At a dark sky site however, I find it hard to pick the 4 stars in the PAS due to the plethora of other stars that are now suddenly visible.
A kids protractor, a fishing sinker, sticky tape and fishing line.
Put these together and you have a clinometer.
And a cheap compass for finding true south.
That,s what I used before i was GIVEN (lucky me) a Suunto compass and clinometer.
By fitting a straight edge into the dovetail slot (eq5), putting the clinometer on it and setting it for my lat. (20.7 degrees)
Also checked the same on the counterbalance shaft.
One meter VERY straight bit of 30mm Jarra was used in the latitude fork first to set true south of base on pier.
Thanks Centauri. I might have a go at making a protractor unit for its flexibility, as my template is only good for the latitude of Brisbane at 27° 30'.
Here’s the latest development in my eternal quest to obtain a good, rough polar alignment in the daylight at unfamiliar observing sites (e.g. astro camps). The FOV of my Polar Alignment Scope is approx 3° so this altitude technique should get me with ±1° of the SCP.
Basically, it is a 360° protractor glued and screwed to a piece of 20mm x 20mm aluminium angle, with a plumb bob weight attached to a piece of orange line to help read the scale.
Here’s the latest development in my eternal quest to obtain a good, rough polar alignment in the daylight at unfamiliar observing sites (e.g. astro camps). The FOV of my Polar Alignment Scope is approx 3° so this altitude technique should get me with ±1° of the SCP.
Basically, it is a 360° protractor glued and screwed to a piece of 20mm x 20mm aluminium angle, with a plumb bob weight attached to a piece of orange line to help read the scale.
An illustrated update to show the importance of adjusting for Magnetic Variation, when polar aligning on the South Celestial Pole, illustrated in this example for Brisbane where True South is approx. 11 degrees E of Magnetic South.
You can obtain the precise magnetic variation for your location and the current year, from here.
An illustrated update to show the importance of adjusting for Magnetic Variation, when polar aligning on the South Celestial Pole, illustrated in this example for Brisbane where True South is approx. 11 degrees E of Magnetic South.
You can obtain the precise magnetic variation for your location and the current year, from here.
Cheers
Dennis
Thats a fantastic example of pure engineering excellence , and also how to set up for Duckadang . Can you please bring your Girl guide rig along so we can test it out, as we will be coming from south of the border we might need all the help we can get, being this far north we may get nose bleeds .
on a more serious note though, I watched a programme some time ago speaking of the reversal of the magnetic poles and that currently we are in a huge state of flux where the magnetic forces are at their weakest. I wonder how much it would effect this setup in the near and distant future ?
Thats a fantastic example of pure engineering excellence , and also how to set up for Duckadang . Can you please bring your Girl guide rig along so we can test it out, as we will be coming from south of the border we might need all the help we can get, being this far north we may get nose bleeds .
on a more serious note though, I watched a programme some time ago speaking of the reversal of the magnetic poles and that currently we are in a huge state of flux where the magnetic forces are at their weakest. I wonder how much it would effect this setup in the near and distant future ?
Hi Dave
Yes – I’ll bring the templates and devices to Qld Astrofest and we can apply them to your mounts which should get you within 1 or 2 degrees of the SCP. Not too sure if the “compass on a stick” will fit your tripod head, but we’ll give it a bash.
If we suffer a magnetic reversal, and also survive it, provided it settles down and becomes stable, I can just re-set the compass to the new off set value and she’ll be right again.
Looks like something I could use on my mount. Always find that the az adjustment is the one I have a problem with. Levelling with the bubble and altitude scale seems to fix the altitude OK, but I have to hunt for a few minutes to get the azimuth in the right ballpark. Maybe your compass idea would speed things up a bit. I'll put it on my (long) list of things to get organised.
If we suffer a magnetic reversal, and also survive it, provided it settles down and becomes stable, I can just re-set the compass to the new off set value and she’ll be right again.
I remember hearing something about this a few years ago.
It would be interesting to see the affect it would have on electronic equipment. I know for a fact that everything using a CRT like TV's and old PC monitors would become useless overnight, unless they are sent off for service. Or we could swap TV's with the people in the northern hemi ;D
I remember hearing something about this a few years ago.
It would be interesting to see the affect it would have on electronic equipment. I know for a fact that everything using a CRT like TV's and old PC monitors would become useless overnight, unless they are sent off for service. Or we could swap TV's with the people in the northern hemi ;D
OK, a blast from the past, but I had to bring post #16 back to life. I've just started playing with an EQ5 and this little jig for altitude adjustment looks brilliant, thanks Dennis!
I first set the system up at my home location and used it to set the altitude and azimuth as per the compass and protractor templates. I then fitted the German Equatorial Mount and aligned it using the built in Polar Alignment ‘Scope using the altitude and azimuth adjustment screws.
This gave me my baseline set up. I now only unscrew one of the azimuth adjusters to remove the mount from the tripod head; in my case, I selected the western azimuth adjustment screw.
Therefore, when I set up the mount again either at home or at a mobile location, after setting up the tripod with my home made templates, I fit the GEM head and only screw in the Western azimuth adjustment screw and this gets me within less than one degree of the SCP.
The Eastern side azimuth adjustment screw always remains untouched, acting as a fixed reference point. Thus, the mount always returns to the same position relative to the post that the azimuth adjustment screws push against.
along so we can test it out, as we will be coming from south of the border
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