Skyscript Astrology Forum

I hope this is the right section to post this.

I need some help about the observation of Halley comet in September 1301.

A text of the time says the comet was in Scorpio, but I checked with my astronomical software -Starry Nights- and it put the comet in Gemini:(

I can't find find any ephemeris for that period. Someone knows where it was the comet in September/October 1301?

Any help would be appreciated and acknowledgements given, obviously.

margherita

Gjiada wrote:A text of the time says the comet was in Scorpio, but I checked with my astronomical software -Starry Nights- and it put the comet in Gemini

Hi Margherita,

I couldn't open this after googling it but here are some sentences just copied from the search result:
"Halley?s Comet Through the Agesobserved it and carefully noted its changing position from night to night .... finally went out of sight on October 25 when in Scorpius and very low in the ..... Perihelion date = 1301 October 25.58. Closest approach to Earth = 1301 ...
www.springerlink.com/index/n321g4383l13x262.pdf - Similar pages
by D Seargent"

closest approach to earth:
Halley?s Comet Through the AgesPerihelion date = 1301 October 25.58. Closest approach to Earth = 1301. September 23, 0.18 AU. On this return, Halley?s

Ah.. here's the book where the quotes came from
http://books.google.nl/books?id=DFgMAaU ... t#PPA50,M1

Further here are some tables, in Right Ascension and Declination so they need conversion to Ecliptic and Latitude.
http://articles.adsabs.harvard.edu/cgi- ... lassic=YES

Or start from here (same article) http://adsabs.harvard.edu/full/1986JRASC..80...62Y
page 75

As you can see Halley travelled very fast from the summer solstice point near 6h Right Ascension early september to 16h RA (or close to tropical Scorpio and Sagittarius) The notations of the positions in the past may have been done in the sidereal zodiac / constellations. Also note that in those days the Julian Calendar was used. I don't know if the article corrected for the dates. Better check several things comparing it with some Astrodienst online data or a NASA and JPL website.

In fact Halley was probably in (tropical) Gemini somewhere in august and travelled very fast to Scorpio. The speed can be explained because Halley was 0.18 Astronomical Units from Earth at its closest passage. Also note the fast increase and decrease of declination.

So maybe your computer program of the position in Gemini is correct, but the recording of Halley's position certainly must be.

Eddy wrote: So maybe your computer program of the position in Gemini is correct, but the recording of Halley's position certainly must be.

So many thanks, I'm a Virgo Sun and I'm a little maniac

The astronomical software shows chosen points in constellations.
so at this point I believe it is good for present but not for past centuries.
You saved my Virgo life

Margherita

Do you manage to convert the equatorial positions to ecliptical?
http://en.wikipedia.org/wiki/Ecliptic_c ... oordinates

Note that on page 71 of the article with the tables that the equatorial positions are set for the equinox of 1950 (it's a common usage among astronomers to determine positions for a fixed date of equinox, 1900, 1950, 2000 etc.)
Furthermore the article mentions that the dates before 1582 are based upon the Julian Calendar so the difference in 1301 with the Gregorian calendar would have been about 8 or 9 days. However if you want to I can give it a try and convert them to ecliptical positions, but that might not be before the weekend.

By the way, just out of curiousness. Do you want to know the position of Halley's comet in relation with Giotto the famous Italian painter?

Hi Eddy,

By the way, just out of curiousness. Do you want to know the position of Halley's comet in relation with Giotto the famous Italian painter?

I am doing a talk on comets in astrology soon and I was going to mention Giotto's Adoration of the Magi so that would be really handy for me too!

Mark

Eddy wrote: By the way, just out of curiousness. Do you want to know the position of Halley's comet in relation with Giotto the famous Italian painter?

Some say it's an awful gossip, but I will mention more details in my article, an author has her secrets

Thanks for detals about coordinates, in every case it's just a translation, I just would check why the astrologer wrote "Scorpio" when Starry Nights put Halley in Gemini.

Margherita

I'll post the positions this weekend. I hope they will be correct. Unfortunately I have no other reference to compare the results.

As far I can say now, Halley must have been in the middle of tropical Scorpio at about 1 October and in ecliptic conjunction with the star Antares half october. Till begin september Halley would have been in tropical Gemini and in the middle of september in conjuntion with the stars Castor and Pollux. So the Starry Nights program isn't necessarily wrong, neither was the astrologer's comment. It is just the fact that Halley moved very fast in a short time.

Eddy wrote:I'll post the positions this weekend. I hope they will be correct. Unfortunately I have no other reference to compare the results

Hello Eddy,
don't worry, I'm trying to finish the traslation before that date.

But you helped me a lot confirming that Halley was in Scorpio in October 1301.
Many thanks again,
Margherita

Ah, let?s write it all down right now anyway .
First some technical remarks. The used equinox was 1950. The obliquity of the ecliptic then was 23,4457889. To convert from the 1950 equinox to that of 1301 the correction for precession to tropical coordinates is required. As the annual rate of precession slightly changes I calculated the average annual rate of precession in 1626. This year is halfway between 1950 and end of 1301. Result is 0?0?50.216? or 1? in 71.69 years. Over the whole period this gives a rate of precession of 9?2?. I converted the Halley positions from equatorial to ecliptic coordinates and applied the issues mentioned above.

1301 Tropical positions ecliptic, longitude and latitude
Halley Sun (source: Astrodienst Ephemeris)
September
1st 24?50?Gemini +3?36? 15?48? Virgo
11th 1?24?Cancer +9?54? 25?36? Virgo
16th 9?52?Cancer +17?54? 0?31? Libra
21st 7?24?Leo +36?35? 5?27? Libra
26th 24?19?Libra +40?48? 10?24? Libra
October
1st 23?48? Scorpio +24?47? 15?22?Libra
11th 4?58? Sagittarius + 13?13? 25?20?Libra
21st 5?52? Sagittarius +8?46? 5?22? Scorpio
31st 4? 2? Sagittarius +5?51? 15?26?Scorpio
Sun?s ingress in Scorpio, 15 October, in Sagittarius, 14 November (also conjunction with Antares).

The following positions of stars and the dates for the equinoxes solstices are from Jean Meeus? book, ?Astronomical Tables of the Sun, Moon and Planets? 2nd edition, Willmann Bell

Stars, Tropical positions 1301 ecliptic (I forgot the latitude but these hardly changed)
Castor/Alpha Gemini 10?32? Cancer
Pollux/Beta Gemini 13?36? Cancer
Southern Asellus/ Delta Cancri 28?59? Cancer
Regulus/Alpha Leonis 20?7? Leo
Spica/Alpha Viginis 14?7? Libra
Zuben El Genubi/Alpha Librae 5?21? Scorpio
Dschubba/Delta Scorpii (the middle of the three before Antares) 22?50?Scorpio
Antares/Alpha Scorpii 0? 2? Sagittarius

1301 equinox/solstice
12 March 21h59m
14 June 3h52m
15 September 11h33m
13 December 20h28m
1302
13 March 3h45m

I didn't calculate the difference in days between the Julian and the Gregorian calendar but it was about 8 ? 9 days.

Note the fast change end September. It makes it difficult to interpolate with certainty. Furthermore I sometimes get different results for the elongations (last column). ?M1? signifies the magnitude or brightness. At closest passage to the earth Halley had magnitude 1 or about the same brightness as Regulus, Spica, Castor and Pollux. Another interesting issue is the high latitude of Halley above the ecliptic. Halley therefore would have been visible several hours after sunset even when in conjunction with the Sun.

I still doubt if the calculations are exactly correct. But they should approximately be within a couple of degrees. (perhaps you would like to compare some results with your computer program Margherita). Moreover the article was written in October 1985. Halley?s perihelion passage took place in april 1986. So new data and new calculating systems could have improved the calculations. Looking a bit through the article one realizes what a tremendous work the scientists did. Actually I remember seeing Halley as a 16year old on perhaps the only clear day of the terrible cloudy and rainy December of 1985. It was just a little dot near the triangle of stars of the ?jug? of the constellation Aquarius. And I had just a little 8x30 pair of binoculars, however I?m glad I saw it, now I don?t have to wait till 2062 .

Eddy wrote:
Ah, let?s write it all down right now anyway .

1301 Tropical positions ecliptic, longitude and latitude
Halley Sun (source: Astrodienst Ephemeris)
September
1st 24?50?Gemini +3?36? 15?48? Virgo
11th 1?24?Cancer +9?54? 25?36? Virgo
16th 9?52?Cancer +17?54? 0?31? Libra
21st 7?24?Leo +36?35? 5?27? Libra
26th 24?19?Libra +40?48? 10?24? Libra
October
1st 23?48? Scorpio +24?47? 15?22?Libra
11th 4?58? Sagittarius + 13?13? 25?20?Libra
21st 5?52? Sagittarius +8?46? 5?22? Scorpio
31st 4? 2? Sagittarius +5?51? 15?26?Scorpio
Sun?s ingress in Scorpio, 15 October, in Sagittarius, 14 November (also conjunction with Antares).

(perhaps you would like to compare some results with your computer program Margherita).

Many thanks, I tried to search Halley in Astrodienst but I was not able
You are surely right, your data agree with the astrologer I'm translating.

In every case this is Starry Nights for the 7th of October - the astrologer mentioned the last day of September, so I checked with Solar Fire Sun position for the old calendar.
Anyway I did not exactly buy the software so it's not a great problem if it is wrong.
Thanks for help and patience, women sometimes are tiring I know.
Margherita

Many thanks, I tried to search Halley in Astrodienst but I was not able. You are surely right, your data agree with the astrologer I'm translating.

Unfortunately Astrodienst doesn't have ephemerides for comets. Anyhow, at least now it can be confirmed that the astrologer in the text wasn't wrong.

Thanks for help and patience, women sometimes are tiring I know.

I like the astronomy part. You are not tiring, the only one who is tiring me is myself. I sometimes tend to spend too much time on astrology .