Adding digital angle gauges (inclinometers):
There are a wide variety of digital tools out there for accurately reading altitude angles and many now have repeatability and resolution of 0.1 degrees, and accuracy within 0.2 degrees.
I like the term inclinometer for such devices that are sensitive to gravity, to avoid confusing them with digital protractors. Digital protractors could work too, provided you set them to a reference object, but inclinometers have a few distinct advantages and help to minimize setup and read errors.
I prefer devices that have silver and black unlit LCD displays. Since I'm reading my azimuth circle with a dim red flashlight it's easy to read such a display with the same. The batteries in an LCD display tend to last almost forever due to their low current draw and they don't have bright illuminated displays to rob night vision.
The original Wixey gauges had bright green displays, the absolute worst color for night vision for DSO observing. In the Degree Circle thread some people have put red film over such devices, and that helps considerably if that's what you have.
These original Wixey devices also had only one scale for level and some couldn't even be zeroed. You'll see on the Degree Circle thread some members mounted these on hinges with screws for tweaking level.
What I have and love is a newer model, Wixey WR365. A link that works at the time of this writing for these is here. Current prices shipped appear to be $36 to $46 USD. The link is to one of the more expensive sources, but I expect that link will work longer than most.
An image of it is here:
I like the fact that there is a fixed level scale on these and one that can be zeroed anywhere. It retains its setting if it times out from inactivity, so a single poke of the ON/ZERO button brings it back up at any altitude angle.
The display can be tilted up for better readability, which I REALLY LIKE. I like to mount my Wixey on a steel plate on the top of my semicircular altitude bearing, which is angled about 45 degrees to my optical tube. This way it is tilted only 45 degrees left and right as the scope is pointed from zenith ro the horizon.
Here again is the view looking down from my eyepiece.
For setup, I first use the device on the bottom of my rocker box and use the fixed scale to level the three adjustable feet on the folding base. I then put the gauge on the altitude bearing and aim the scope close to the horizon so that the fixed scale shows 45 degrees. I zero the other scale at that point to be rough aligned with the scale I use. At this point the scope is roughly leveled and the altitude gauge is very close.
To fine tune level of the scope, I press the scope firmly down to make sure the feet have settled firmly, and adjust the leveling feet to give the same altitude reading (close to zero) in every compass direction. I point the scope over one foot, perhaps the north one, and adjust that foot so that I get the same reading when I point north or south. I then point east and west and adjust the other two feet EQUAL AND OPPOSITE AMOUNTS until I get the same reading east and west. Finally, I repeat the north and south checks to verify them, or to fine tune. By adjusting east and west feet equal and opposite amounts the north and south leveling is maintained.
To fine tune the altitude gauge, I use the current coordinates of Polaris if possible, though if I'm quick, any astronomical object would do. With a high power eyepiece I defocus so that the target nearly fills the field of view. This helps with centering. I zero the gauge when the target is centered. Note that Polaris varies nearly 0.7 degrees above and below your latitude angle, so use current coordinates from a good star app. I like Sky Safari.
Now aim the scope to the horizon until you see the current altitude of your previously chosen target displayed in the opposite direction. The Wixey WR365 doesn't show plus and minus but does indicate with pictures left and right. If Polaris was at 41.5 degrees when I zeroed on it, then I rezero with the scope pointed level and reading 41.5 degrees the other way.
Altitude is now set, even if the gauge is tilted to any angle with respect to the scope.
Setting azimuth is even easier. I like to choose a low object east or west since such objects are barely drifting in azimuth during this process, but again, anything will do if you are quick.
Point at a known object, defocusing again to help with centering, and simply spin the setting circle until it agrees with azimuth coordinates on an app. For precision and repeatability I aim at the object with a clockwise motion of the scope.
If you use Sky Safari and choose to center the object on your screen, the top of the screen will display up to the second coordinates. If you zoom in you'll get coordinates in degrees, minutes, and seconds. IF YOU PAN OUT YOU'LL GET DECIMAL DEGREES. This feature helps with matching both the circle and inclinometer, which are read in decimal degrees.
PIECE A' CAKE!
Edited by jtsenghas, 05 August 2020 - 06:36 PM.