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Skyscript Astrology Forum

Comets

 
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jonflanery



Joined: 30 Oct 2005
Posts: 10
Location: Dayton, Ohio, USA

Posted: Sun Oct 30, 2005 6:41 am    Post subject: Comets Reply with quote

Hello All -

I have been having trouble locating information on the visible comets of 2004 and 2005. I have been to several sites but I noticed that on the astronomical sites youhave to be quick to snag the information. They usually give current ephemeris information and if you happen to be lucky enough to get one with the perihelion date included, great; otherwise you may be out of luck.

Any assistance finding this data appreciated. I am of the opinion that this along with eclipse data will shed light on the recent earthquakes and huricanes.

I'm also looking for a reliable algorithm to convert RA and Decl to Ecliptic Long and Lat.

Any assistance is appreciated.

Jonathan
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Deb
Administrator


Joined: 11 Oct 2003
Posts: 4130
Location: England

Posted: Wed Nov 23, 2005 10:21 am    Post subject: Reply with quote

Hi Jonathan,

I meant to answer this post ages ago. This is the best link I have been able to find for information relating to comets. There are some other good ones, but youll find them listed on this sites links page:

http://comets.amsmeteors.org/

But its still not very easily accessible information for astrologers. I would personally struggle to find the information I was looking for from sources on the web and dont know of anything better off it. If anyone else can make suggestions, Id be interested too.

Im not sure if you still need the calculation details. There is a page on this site ( http://www.skyscript.co.uk/ra.htm ) that gives a fairly reliable table for converting longitude to RA. I can give you the formulas to find Right Ascension or Declination where longitude is known would that be any help or do you already have that?
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jonflanery



Joined: 30 Oct 2005
Posts: 10
Location: Dayton, Ohio, USA

Posted: Fri Nov 25, 2005 4:35 pm    Post subject: Comets Reply with quote

Hi Deb,

Thank you. Yes, I agree that Gary Kronk's site is a very good one and that most of the purely astronomical sites are not easy to use. His site contains at least the dates of perihelion and magnitudes for major recent comets and perhaps by contacting him the exact information can be obtained. Data on historical comets is harder to find but Ephemeris of the Great Comets 1402-1948 by Carl Ramus includes most of the technical information needed to get started with historical studies. A Ramus update filling in the blanks and providing some historical correlation and astrological consideration would be a very welcome addition. I think it is out of print with AFA holding the copyright. But, I could be wrong about that.
-
I just recently purchased Practical Astronomy for your Calculator which includes conversions between reference systems and how to make use of the orbital elements the astronomers always give for comets. Given a bit of time, I think I can turn this into a useful program for my needs and offer it as a feature on my web page for coordinate conversion. This would make it a lot easier for me and for others to use comets and other celestial phenomena when only the astronomical information is available.

The tables on Skyscript can be useful when you want to match up RA with Ecliptic (Zodiacal) Longitude or locate something with little or no latitude. It's a step. Thanks for mentioning it. The problem is that many items of interest have appreciable latitude and do not map directly to the ecliptic. For example, Nova 1987a was nearly at the South Pole and Nova Cygni (1975) was about half way to the North Pole. Comets at perihelion and appearance can be some distance from the reference circles of the equator and ecliptic as well.

Thanks again for this response.
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Deb
Administrator


Joined: 11 Oct 2003
Posts: 4130
Location: England

Posted: Tue Nov 29, 2005 11:11 am    Post subject: Reply with quote

I hope you manage to create that program for your website. There is certainly a need for it. Astrologers go so quiet on comets until we get one that attracts a bit of media attention then everyone scrambles !

You need to adjust the right ascension where latitude is concerned. Add in the ascensional difference to find the oblique ascension. The formulas are:

OA = RA AD

Where:
OA = Oblique ascension
RA = Right Ascension
AD Ascensional difference


To find the AD use the formula:

AD = ArcSin (Tan declination of degree x Tan geographical latitude)

The geographical latitude is the latitude of the place where the chart is being drawn.
The declination of the degree (DD) is itself found from the formula:

DD = ArcSin(Sin oe x Sin ablong)

Where
oe = obliquity of the ecliptic (2330)
ablong= absolute longitude of the planet (or comet, etc)

This is the sort of thing that usually makes me want to stick my fingers in my eye sockets and wiggle them around, but its actually very easy to do with a calculator, as I discovered after much frustration.
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Coder



Joined: 14 Dec 2004
Posts: 143

Posted: Thu Aug 10, 2006 4:04 pm    Post subject: Reply with quote

Quote:
They usually give current ephemeris information and if you happen to be lucky enough to get one with the perihelion date included, great; otherwise you may be out of luck.


JPL data here: http://ssd.jpl.nasa.gov/?sb_elem - includes time of perihelion passage for comets (Julian date) - but not unfortunately visual brightness data.

ZET 8 has been recently enhanced to handle all comets with computed orbital parameters. Data can be cut and paste from the above source into ZET 8 and used for astrological purposes. The precise details are here: http://www.zaytsev.com/EngUG/asteroids.html. Once inserted into ZET, comets can also be displayed in its astronomical tableaux (celestial sphere, solar system simulator) and animated over any time interval - which will help you find them if they are visible.

AFAIK this facility for comets is present in the freeware Lite version as well as the commercial versions.
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granny_skot



Joined: 20 May 2004
Posts: 1634
Location: California, USA

Posted: Thu Aug 10, 2006 6:08 pm    Post subject: Reply with quote

stupid question...

There was a Visible comet in the late 90's, the one where a bunch of fools in San Diego commited suicide so the mother ship could bring them up, and for the life of me I can't remember the name of that comet, it was visible for a long time and I used to drive home in the evening with it lighting the way, it was an incredible sight to behold.

anyway, if someone could supply the comet name for me I'd appreciate it.

Granny...
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Deb
Administrator


Joined: 11 Oct 2003
Posts: 4130
Location: England

Posted: Thu Aug 10, 2006 6:13 pm    Post subject: Reply with quote

If it was 1997 it was Hale Bopp
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granny_skot



Joined: 20 May 2004
Posts: 1634
Location: California, USA

Posted: Thu Aug 10, 2006 7:08 pm    Post subject: Reply with quote

that would be it, I've never seen anything quite so up close and personal in the sky, until a few years later when a Jet Crashed into the Pacific Ocean in about the same setting pattern, (Alaska Airlines, it was horrible) HB was very large in the sky here in Southern CA, certainly has a funny name, I was thinking it rhymed with sock hop, but couldn't quite bring it to focus, thank you.

Granny
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Tom
Moderator


Joined: 11 Oct 2003
Posts: 3440
Location: New Jersey, USA

Posted: Thu Aug 10, 2006 7:20 pm    Post subject: Reply with quote

The leader of the cult was one Marshall Applewhite

May 17, 1931
3:20 AM
Spur, Texas, USA
33 N 28' 35"
100 W 51' 19"

This was a second attempt to leave the Earth by Applewhite. In the 70s he and his wife (known by their followers as "The Two" or sometimes "Bo and Peep") persuaded a group of people to sell off all their worldly goods and go to the top of a mountain where they would be flown to Heaven in a flying saucer. Somewhat surprisingly, the saucer never showed up. Applewhite's equally unbalanced wife, Bonnie (nee Nettles) died in 1985 I"m not sure if the disappointed space travellers became Heaven's Gate or if he formed a new group after that.

I don't wish to resurect the "Algol" thread but Applewhite was born under a new Moon on Algol.

Tom
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