Hi everyone,

I'm trying to understand how to convert astronomical comet data into astrological ecliptical data.
That is, in which sign and degree the comet would travel.

Found several sites which give the astronomical data for comets, but I can't seem to get, how to convert it into degrees on the ecliptic.
ChatGPT and another astrologer suggested using mathematical formulas, but I wonder if there's a simpler way.

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This is an example of a site which gives an astronomical ephemeris (in right ascension & declination) for comets:
https://www.unistellar.com/citizen-scie ... /ephemeris

For example, if we take comet Pons-Brooks for the coming solar eclipse of 8-APR-2024, for the location of New York City, the astronomical ephemeris would show that it is in:
2 hours, 40 minutes - right ascension
+18 degrees 27 mins - declination

But where would it be on the zodiac wheel?

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Or maybe there's another way, which is more simple, to ephemerize comets?

Thanks,
Dima.

Hello Dima,

https://www.swift.psu.edu/toop/convert.php

RA corresponds to longitude (15 degrees of longitude = 1h of RA. So 2h40' = 2.666 X 15 = 40 degrees or 10 Taurus.)
DEC corresponds to latitude

Maybe there are more sophisticated websites to consider the place of the observer. Would be curious to learn more about this.

Best to you,
Ouranos

This website does the job.

https://ned.ipac.caltech.edu/coordinate_calculator

Just set it to output in the ecliptic system:

43.322605 degrees longitude (13° 19' 21.38" tropical Taurus)
2.740811 latitude (2° 44' 26.92" of latitude in that place)

Perhaps the most important thing to understand is that objects in the sky are not necessarily located anywhere in the zodiac belt at all, although their positions can be projected onto the ecliptic. (That goes for many of the fixed stars as well.) In this case, though, the positions given do correspond to a position within the zodiacal boundaries.

You do need to use mathematical formulae, or get software to do it for you. I see that Gemato beat me to it, but here is another website that does the same:
https://frostydrew.org/utilities.dc/con ... ordinates/

Thanks for everyone who answered.

Now, this conversion table by Deb Houlding makes more sense:
https://www.skyscript.co.uk/ra.htm

Ouranos: Actually remembered, thanks to your calculation that 2 hours is 0 tau, 4 hours is 0 gem, 6 hours 0 can, .... , 22 hours 0 pis, etc.

Gemato: thanks for calculator.

Martin: Am aware of the projection to ecliptic thingy (also with f.stars), although did not mention it in the original post.
Kinda makes me wonder if you use F.Stars the "Vivian Robson method" (projecting) or the B. Brady method (parans and co.).

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I think now that with that comet ephemeris site (https://www.unistellar.com/citizen-scie ... /ephemeris)
and with the ability to convert, it becomes rather easy to pinpoint the location of comets onto an astrological chart.

When I do use fixed stars (which isn't regularly), I consider their actual location in the sky, not their ecliptical projections. I haven't read Brady's book(s?) on the subject.

Dima Gur wrote: Mon Jan 15, 2024 8:54 pm Now, this conversion table by Deb Houlding makes more sense:

In what way, or perhaps I should say, more sense than what? Please note that the table applies only to points actually on the ecliptic.