Re: RA question

On Mar 5, 5:59 pm, "Ben" <bet71...@xxxxxxxxxxx> wrote:
On Mar 5, 4:55 am, "oriel36" <geraldkelle...@xxxxxxxxx> wrote:



On Mar 5, 8:15 am, "canopus56" <canopu...@xxxxxxxxx> wrote:

On Mar 3, 2:01 pm, Eric <N...@xxxxxxxxxxx> wrote:

If an object is at RA x:yy for example, how do i know where it is in the
sky? I cant figure out how to use RA to determine a point in my view of the
sky.

Your current local sidereal ("cy-dear-e-el") time (LST) can be found
at this handy USNO web applet:

http://tycho.usno.navy.mil/sidereal.html

LST means the right ascension that is currently transiting your south
meridian. You can also follow LST with a planisphere. Orient the
planisphere to the current time. The RA (that corresponds to the
current LST) can be read off the dial plate along the noon-midnight
line.

I found spending a couple of days with my plainisphere, following the
rotation of celestial dome throughout an entire day - including
daylight - helped me to wrap my head around the concept of LST. The
analogy mentioned in this thread about sidereal time as a watch that
runs 3 minutes and 56 seconds fast is a good one.

Why 3:56 minutes fast? If the Earth were just hanging motionless in
space rotating on its axis, the solar day would have a nice equal 24
hours periods. But the Earth also revolves around the Sun. Because
the Earth also is moving along a tangent to its solar orbit, the Sun
gets to back to local solar noon 3:56 minutes "faster". The 3:56
minutes represents the linear travel of the Earth in its orbit around
the Sun.

Enjoy - Canopus56

.

and Oriole enjoins:

The real bonus is appreceating how clocks were developed to keep in
sync with axial rotation when it was promoted by Copernicus as the
cause of the daily cycle.

Honor Copernicus by not mentioning his name.

Ben- Hide quoted text -

- Show quoted text -

Your cult dishonors all astronomy,not just the Copernican insight.

Clocks are kept in sync with axial rotation as a principle,as
Copernicus resolved the observed behavior of the other planets through
assigning an orbital motion to the Earth it allowed him to justify the
daily cycle through the axial rotation of the Earth.

Then we have Newton -

"For to the earth they [planetary motions] appear sometimes direct,
sometimes stationary, nay, and sometimes retrograde. But from the sun
they are always seen direct..." Newton

When you make an error in approaching and resolving retrogrades like
Newton did you can forget about how clocks are kept in sync with axial
rotation at 4 minutes for each degree making exactly 24 hours/360
degrees.

I honor Copernicus by affirming that we see the orbital motions of
ourselves and the other planets around the Sun from an orbitally
moving Earth -

http://antwrp.gsfc.nasa.gov/apod/image/0112/JuSa2000_tezel.gif

When you crowd decide to do the same,only then will you know how
clocks are kept in sync with axial rotation as an adaption of the
human devised principles which created the 24 hour day.








.

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