The Ecliptic is a circular band surrounding the Earth,which marks the apparent path of the sun through the heavens.
My question is:
How wide is it?
Is it measured in degrees?
A quick search on my part yielded a bunch of astrology sites,but I was unable to find the answer to my basic question.
Thank you.
Forbin
I believe that the Ecliptic can be measured in either degrees or months/days. I’m not sure what you mean by “wide” but the eclipitc encircles the entire earth, 360 degrees. It’s and imanginary line that only exists from the perspecitve of the earth, so it doesn’t have an actual radius.
The ecliptic is an imaginary line projected onto the celestial sphere that marks the path of the sun. It may help to visualize it from outside the Earth - in which case the plane of the Earth’s orbit is called the plane of the ecliptic. See a quick definition here. Since it is an imaginary line, it has no width. It’s like asking “how wide is the equator?”
I do understand that it is a line,and therefore has no dimensions.
However,in most depictions I have seen it is represented by a band large enough to contain each of the twelve constellations for which it is most famous.
Perhaps I didn’t say that quite right,but what I mean is that it is sufficiently “high” to contain each of the twelve.
It is possible that the band typically displayed has another name,and is not meant to represent the Ecliptic proper.
While being an imaginary line with no width per se, it runs through the twelve constellations of the Zodiac, so it’s often shown as a band wide enough (is that what you meant by ‘high’?) to contain those constellations. There’s really no official ‘size’ to it at all.
Well,I think perhaps what I’m in search of is,“The Zodiac”.
Or perhaps,“The Band of the Zodiac”.
A friend just told me that it is fifteen degrees in width.In other words it is seven and one half degrees above and seven and one half degrees below the ecliptic.
Somebody knowledgeable about astronomy is bound to come along soon and enlighten me.Thank you all for your help.
Forbin
(BTW I am not suggesting anyone who posted so far was not knowledgable.Problem is I have but poorly expressed what it is I’m looking for so far.Perhaps my latest post will make it clearer.)
The different constellations have different N-S extensions but you can roughly say that a band 30 degrees wide would pretty much cover them all.
I’m not sure how much light I’m going to be able to shed on the matter, but I’ll throw in my 2¢ as well.
Modern astronomy has divided the sky up among the constellations much like county or state lines, giving each constellation a “territory”; celestial objects are thus said to be ‘in’ a constellation. Ancient astronomy did this as well but nowhere nearly as precisely as yer boys over on Palomar there.
It does, as the OP mentioned, track the apparent path of the sun through the heavens. I don’t believe it’s measured in degrees simply because the Sun takes 365.25 days to go around the ecliptic once; my Uranometria 2000.0 marks the Sun’s position by days, IIRC. Of course, the ecliptic is therefore going to cross the “territory” of certain constellations, and it is these fourteen constellations which constitute the Zodiac. (Yes, I said fourteen. Of course we have the famous twelve of astrology, plus two whose territories lie on the ecliptic for no more than a few days at a time. Bonus points to the person who can name them.)
As for how “wide” it is, that probably refers to the fact that the five visible planets - Mercury, Venus, Mars, Jupiter, and Saturn - are all roughly on the same orbital plane as the Earth, hence they appear to cling to the ecliptic as well. The ecliptic’s “width” would be the maximum distance to which any planet would deviate from the ecliptic. I dunno what that distance is, however.
Here’s another angle on the OP (haw, haw angle get it?)
The earth’s axis of rotation is tilted 23.5 degrees from the plane of its orbit. On the celestial sphere, the ecliptic is tilted by this amount with respect to the celesital equator (CE).
So, let’s say you’re at a mid-latitude in the northern hemisphere. Each day at noon, you measure the angle between the southern horizon and the sun. The smallest angle will occur at the winter solstice (23.5 deg below the CE). At the equinoxes, it will be right on the CE (BTW, the autumnal equinox was just last Saturday), and at the summer solstice, it will be at its highest point 23.5 deg above the CE.
So, during the year, the sun makes its way along a swath of sky 47 degrees wide, in a sense.