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Flatangle Charts - High quality charts
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zoidsoft



Joined: 10 Feb 2006
Posts: 991
Location: Pulaski, NY
Posted: Wed Mar 18, 2015 1:48 pm    Post subject: Reply with quote
jventura wrote:
Hi Curtis,

I'm following a simpler approach which is to define a planet as stationary when its longitude speed is less than 1 arc-second. There are other approaches, but it seems no one knows which is the "correct" one.. Smile

The source code is quite simple: https://github.com/flatangle/flatlib/blob/master/flatlib/object.py#L131


Joćo Ventura


Yes... Speed is the 4th value in the array xx[0.6] returned by the Swiss Ephemeris (which uses iteration btw). I was referring to finding the date/time of a station, not whether a planet happens to be stationary at a given moment which is a different problem. The problem with using speed is that different planets have different averages (which is not much of a problem if you set which constant to use), but if you're using speed alone without the correct iteration interval, you risk skipping over an instance of stationary movement during the course of the year.

I have my own set of calculations based upon Jean Meeus's Astronomical Algorithms which I never completely finished because then I found the Swiss Ephemeris.
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jventura



Joined: 04 Jan 2011
Posts: 294
Location: Portugal
Posted: Thu Mar 19, 2015 1:05 pm    Post subject: Reply with quote
Hello everyone,

I'm happy to announce a new update to the Charts web app! It features a redesigned interface and some minor error corrections. Smile

Find it at http://apps.flatangle.com/Charts/


Enjoy,
Joćo Ventura


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Astraea



Joined: 04 Oct 2004
Posts: 355
Location: Colorado, USA
Posted: Thu Mar 19, 2015 2:32 pm    Post subject: Reply with quote
I just want to thank you again for this lovely, much-needed web app. Having the terms present on the chart is so helpful, and the form and fonts are beautiful.
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Martin Gansten
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Joined: 05 Jul 2008
Posts: 1268
Location: Malmö, Sweden
Posted: Thu Mar 19, 2015 6:05 pm    Post subject: Reply with quote
Indeed, it looks great. I'd love to use it, and so, I'm sure, would many others who use a sidereal zodiac (which, incidentally, is the zodiac in which the terms first appeared). Any chance of an ayanamsha feature, Joćo?
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pankajdubey



Joined: 17 Nov 2006
Posts: 1219
Location: Delhi
Posted: Thu Mar 19, 2015 6:10 pm    Post subject: Reply with quote
jventura wrote:
Hello everyone,

I'm happy to announce a new update to the Charts web app! It features a redesigned interface and some minor error corrections. Smile

Find it at http://apps.flatangle.com/Charts/


Enjoy,
Joćo Ventura




Thanks,

looks good but when the planet is on the cusp of the angles it's degree and minute values get partially masked.There should be a separate column for the planetary data.
eg: if saturn is on the cusp of Asc- 4 deg 54 min- then it is not clear if it 54 mins or 34 mins as the thickness of the line occludes the top half of 5.

PD
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jventura



Joined: 04 Jan 2011
Posts: 294
Location: Portugal
Posted: Thu Mar 19, 2015 9:08 pm    Post subject: Reply with quote
Astraea wrote:
I just want to thank you again for this lovely, much-needed web app. Having the terms present on the chart is so helpful, and the form and fonts are beautiful.


Hello Astraea, and thanks for the compliment! Smile

Martin Gansten wrote:
Indeed, it looks great. I'd love to use it, and so, I'm sure, would many others who use a sidereal zodiac (which, incidentally, is the zodiac in which the terms first appeared). Any chance of an ayanamsha feature, Joćo?


Hello Martin, I've been somewhat busy rewriting the code for my other project flatlib. But I hope to implement the sidereal zodiac as soon as possible.. Smile

pankajdubey wrote:

Thanks,

looks good but when the planet is on the cusp of the angles it's degree and minute values get partially masked.There should be a separate column for the planetary data.
eg: if saturn is on the cusp of Asc- 4 deg 54 min- then it is not clear if it 54 mins or 34 mins as the thickness of the line occludes the top half of 5.

PD


Hello Pankajdubey, you are quite right! Smile My availability is low currently, but I'm planning to include more features in next releases, including information in tabular form (planetary hours, planet data, etc.).


Thank you all,
Joćo Ventura
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Martin Gansten
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Joined: 05 Jul 2008
Posts: 1268
Location: Malmö, Sweden
Posted: Fri Mar 20, 2015 9:00 am    Post subject: Reply with quote
jventura wrote:
But I hope to implement the sidereal zodiac as soon as possible.. Smile

Wonderful! Thank you.
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jventura



Joined: 04 Jan 2011
Posts: 294
Location: Portugal
Posted: Fri Mar 20, 2015 5:36 pm    Post subject: Reply with quote
Martin Gansten wrote:
jventura wrote:
But I hope to implement the sidereal zodiac as soon as possible.. Smile

Wonderful! Thank you.


Hi Martin,

I've opened this thread on the sidereal section of the forum, to see if I can integrate the sidereal zodiac in my software library at a deeper level.

When you have available time, could you reply there?


Thanks,
Joćo Ventura
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skyrack



Joined: 02 Aug 2012
Posts: 192
Location: Thailand
Posted: Thu Apr 09, 2015 2:04 pm    Post subject: Reply with quote
Joćo and Zoidsoft,

I have recently been working with Paul Schlyter's algorithms for calculating planetary positions.
This is, I believe, based on Jean Meeus's Astronomical Algorithms which zoidsoft has mentioned using.

And I have been using Michael P. Munkasey's House Formulary for calculating MC and ASC.

The algorithms for calculating planetary positions are producing good results, but when comparing my calculated MC and ASC to those produced by Astrodienst there is a difference that cannot be ignored.

I note that flatangle also produces MCs and ASCs slightly different from Astrodienst (about half of a degree in the one chart I have compared).

This may be only a slight discrepancy but these are important angles and given the same data of time and place I would expect results to be the same to within 1 arc second.

Adding the Local Sidereal Time to the flatangle chart would be useful.

Any help anyone can offer on calculating the MC and ASC would be more than welcome.

Joćo please don't take my criticism the wrong way. What you have done is quite illuminating especially with the terms and decans included.
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jventura



Joined: 04 Jan 2011
Posts: 294
Location: Portugal
Posted: Thu Apr 09, 2015 7:27 pm    Post subject: Reply with quote
skyrack wrote:
I note that flatangle also produces MCs and ASCs slightly different from Astrodienst (about half of a degree in the one chart I have compared).


Hi skyrack,

I use the Swiss Ephemeris, which is the ephemeris from the Astrodienst guys, so it should return the same results. Did you check the timezone? Sometimes people enter the wrong timezone data..

If it's possible, you can send me the data to my email and what results it should give, and I'll try to see if there is any error. My email is flatangleweb at gmail.com


Joćo Ventura
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zoidsoft



Joined: 10 Feb 2006
Posts: 991
Location: Pulaski, NY
Posted: Fri Apr 10, 2015 5:05 pm    Post subject: Reply with quote
Time zone being off by 1 hour usually produces an ascendant difference of 10-20 degrees. I'd check the location data next to make sure that latitude and longitude are correct. One factor that affects the ascendant is delta time which is estimated differently depending upon the source and the era. In the Swiss Ephemeris this is calculated automatically in the conversion from UTC to ephemeris time and the function used to calculate house cusps can use either ephemeris time or universal time. A possible error here is using one time standard when another is called for. A difference of 1/2 degree is about 2 minutes of clock time.
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jventura



Joined: 04 Jan 2011
Posts: 294
Location: Portugal
Posted: Fri Apr 10, 2015 5:44 pm    Post subject: Reply with quote
Hi Curtis,

in this case it was simply a problem with the location data..


Joćo Ventura
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skyrack



Joined: 02 Aug 2012
Posts: 192
Location: Thailand
Posted: Sat Apr 11, 2015 1:51 am    Post subject: Reply with quote
Yes, I had made a small error in the location coordinates which caused the discrepancy. Thanks to Joćo for looking into it.

Zoidsoft,

Delta time - is that the same as the Equation of Time?

Skyrack
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zoidsoft



Joined: 10 Feb 2006
Posts: 991
Location: Pulaski, NY
Posted: Sat Apr 11, 2015 5:16 am    Post subject: Reply with quote
skyrack wrote:
Yes, I had made a small error in the location coordinates which caused the discrepancy. Thanks to Joćo for looking into it.

Zoidsoft,

Delta time - is that the same as the Equation of Time?

Skyrack


How technical do you want to get? (essentially the same subject matter) Delta time is the difference between TT (Terrestrial Time) and UT (Universal Time). Astronomers need a universal constant time change that is not based upon the variability of the earth's rotation and other astronomical motions which vary (which is defined as UT, not TT as one might think based upon the name because UT is not really universal). There are many factors that affect the earths rotation such as tidal acceleration, earthquakes (the tsunami of 2004 was a big one). Delta time is measured in seconds and is typically added or subtracted at the end of the year (leap seconds). But during the year, the Sun moves faster (winter in north hemisphere) and moves slower in summer (north). This causes the difference from noon one day to the next to be variable depending upon the time of the year (the difference between Apparent Solar Time and Mean Solar Time).

For astronomical purposes, UT needs to be converted to ephemeris time (aka dynamical/terrestrial time - which is closest to the value of atomic clocks). The EOT (equation of time) refers to the difference between apparent and mean time (solar), but mean time is still not dynamical time or TT (Terrestrial Time) because the Mean Solar Time (aka UT) is still a variable whereas TT is a constant.
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skyrack



Joined: 02 Aug 2012
Posts: 192
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Posted: Sat Apr 11, 2015 12:06 pm    Post subject: Reply with quote
Thanks a lot!.

That degree of technicality was just what I wanted.
Thanks again for clarifying that.

Skyrack
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