Astronomical Software for Atari?

[JagChris]

On 4/3/2023 at 1:47 PM, ClausB said:

Could someone compare Atari Planetarium's present planet positions with something like Heavens Above?

Not a planet but i found a discrepancy while comparing Atari Planetarium with a Celestron desktop planetarium I got with one of my telescopes.

 

Locking onto Arcturus in both shows a near ten degree discrepancy..

 

Atari Planetarium lists it at Elevation (example) 24(deg)51'

Celestron Planetarium has it at Altitude 35(deg) 19.065'

 

My location/time/date is set correctly on Atari Planetarium and should be so on the Celestron as it seems to grab location etc from the net. 

 

Both were looked at at the same time of course.

[JagChris]

On 5/5/2023 at 5:44 PM, Keatah said:

Sounds like a lot of work?

 

Anyways, putting the one from Atari Mania through it's paces. So far ok.

 

For those who may have missed it in the SDMax thread my problem was due to SDMax going into screensaver mode and not responding fast enough for Atari Planetarium's liking. All versions work.

[JagChris]

Atari Planetarium vs Starry Night Celestron  Basic Edition

Position taken of the moon tonight on both programs within moments of each other.
 

Since I am assuming altitude on Celestron corresponds with elevation on the Atari Planetarium we have a ten degree discrepancy. But everything else matches.  So it seems the two programs simply calculate the apparent horizon differently. My guess is the formula for that changed in the last 30+ years.

Edited May 25, 2023 by JagChris

[_The Doctor__]

That would be correct even Horoscopes in some publications are adjusted these days as we are slowly drifting out of sync over time. I forget the exact amount now, but I am sure it's searchable.

 

https://www.smithsonianmag.com/smart-news/nasa-didnt-change-your-astrological-sign-stars-did-180960584/

https://www.livescience.com/4667-astrological-sign.html

 

and because this isn't new to us as you can see. The earth wobbles as do other bodies and this changes things. The calculations do not take this into account. It should be fixable, but no one wants to do all that work for so little return, so they just say signs are not science and move on. The math and science are what make sense of these things though. So why not just consider it astronomy and fix it?

 

Either the eternal calcs need to be properly fixed or a periodic calibration needs to be done.

Edited May 25, 2023 by _The Doctor__

[+DrVenkman]

7 hours ago, JagChris said:

Atari Planetarium vs Starry Night Celestron  Basic Edition

Position taken of the moon tonight on both programs within moments of each other.
 

Since I am assuming altitude on Celestron corresponds with elevation on the Atari Planetarium we have a ten degree discrepancy. But everything else matches.  So it seems the two programs simply calculate the apparent horizon differently. My guess is the formula for that changed in the last 30+ years.

So it’s been years since I booted up Atari Planetarium, but does it specify the astronomical epoch to be used? Until 1984, the generally-used epoch was J1950.0

 

Starting around 1984, the International Astronomical Union adopted J2000.0 (and modern astronomy programs use newer real-world data than that, as some objects in the sky have greater apparent motion than others).

 

Here’s some more on the topic: https://en.wikipedia.org/wiki/Epoch_(astronomy)#Julian_years_and_J2000

[JagChris]

4 hours ago, DrVenkman said:

So it’s been years since I booted up Atari Planetarium, but does it specify the astronomical epoch to be used? Until 1984, the generally-used epoch was J1950.0

 

Well shame on you. 😉

 

 ill keep an eye out to see which standards it uses but this seems right at the border of that in development doesn't it?

 

My apparent horizon is several degrees above either program with the trees and the neighbors crap. As of last night it was a little below Dschubba, the forehead of Scorpius.

 

It surprises me that in some ways Atari Planetarium is easier to use than the Starry Nights Basic. This could possibly be because documentation sucks for the Celestron. After going through the manual on AP and learning that hitting E,S,N or W keys to center in that direction I tried it on the Celestron thinking this has got to work on this newer program and it does. The tutorial and documentation for the newer program is abysmal. Also AP's search function much easier to use. Not as in depth but some of this 40 year old functionality needs to be adopted in some of the newer stuff.

[ClausB]

13 hours ago, JagChris said:

Atari Planetarium vs Starry Night Celestron  Basic Edition

Position taken of the moon tonight on both programs within moments of each other.
 

Since I am assuming altitude on Celestron corresponds with elevation on the Atari Planetarium we have a ten degree discrepancy. But everything else matches.  So it seems the two programs simply calculate the apparent horizon differently. My guess is the formula for that changed in the last 30+ years.

I tried this case on my old ASTRO.BAS (see upthread) for May 25, 5:32 UTC, lat 45d34m, lon 122d20m (best guess for Chris's locale). Got:

RA: 8h45m

Dec: 23d26m

Alt: 28d53m

Az: 274d55m

Much closer than Atari Planetarium, and close to Heavens Above.

 

One possible source of discrepancy between all these is whether the calculated position is geocentric or observer-centric. For the Moon, that difference can be nearly one degree.

[FifthPlayer]

The orbits of the planets, and especially the Moon, are imperfect ellipses that are typically modeled in astronomy software through a giant polynomial (Taylor series expansion) that closely approximates the orbit out to so many digits of precision.

 

The orbits of the planets, and especially the Moon, vary over the years on account of the (chaotic) mutual gravitational interactions between solar system bodies, which requires that the orbital elements and the Taylor series polynomials get updated from time to time from direct measurements.  The Moon's orbit in particular is especially prone to variance because of perturbations caused by Earth's uneven mass distribution, tides, and the Sun, so it represents the worst case.

 

There is also the difference in precession (the wobbling of the Earth's rotation axis) to take into account.  The Celestron program calculates using precession for the current date and for the epoch 2000, not sure what the Atari is using but it's probably at least 30 years old at this point.

 

If you look at the Right Ascension and Declination calculations from both programs (which avoid complications due to local time and latitude/longitude), they're actually pretty close:

 

RA:

Atari Planetarium 08h 39.0m

Celestron            08h 42.59m (epoch now)

 

Dec:

Atari Planetarium 24deg 27 min

Celestron            22deg 54.25 min

 

which says to me that the 10 degree discrepancy in alt/az has something to do with location and time settings being different across the two programs.

 

Edited May 26, 2023 by FifthPlayer

[_The Doctor__]

ASTRO.BAS is y2k compliant ?

[Ricky Spanish]

43 minutes ago, FifthPlayer said:

which says to me that the 10 degree discrepancy in alt/az has something to do with location and time settings being different across the two programs.

NASA calculates using π to 15 digits, so do newer programs/apps. that may account for the slight discrepancy w/ planetarium. 

Edited May 26, 2023 by Ricky Spanish
clarity

[JagChris]

2 hours ago, FifthPlayer said:

RA:

Atari Planetarium 08h 39.0m

Celestron            08h 42.59m (epoch now)

 

Dec:

Atari Planetarium 24deg 27 min

Celestron            22deg 54.25 min

 

which says to me that the 10 degree discrepancy in alt/az has something to do with location and time settings being different across the two programs.

The declination is so close that you can match it on Atari Planetarium just by moving the cursor around and still be within the moon sprite. 

 

Does AP use sprites I wonder?

[ClausB]

In 1982 a present friend and a late friend wrote this delightful Moon phase program on a 400. Today he gave me a dot matrix listing and I OCR'd it, fixed it up, and ENTER'd it into an Atari BASIC emulator.

 

MOONPHAS.BAS in attached ATR.

 

FAFMUL (1).ATR

Edited May 28, 2023 by ClausB

[Ricky Spanish]

1 hour ago, ClausB said:

MOONPHAS.BAS in attached ATR

Thanks !

[ClausB]

Another variation, showing progression of a lunar eclipse.

LUNARECL.BAS in attached ATR:

 

FAFMUL.ATR

[JagChris]

These are pure gold. Thank you.

[JagChris]

On 7/7/2020 at 2:11 PM, ClausB said:

Here's an astronomy program I wrote in 1983: ASTRO.BAS

 

No graphics, just text. It calculates Julian date and sidereal time, it locates planets (including Pluto), and it converts between celestial and altazimuth coordinates. (Yes, my degree is in astronomy and physics.)

FAFMUL.ATR 90.02 kB · 96 downloads

Having trouble with this one. I'm trying to use this website with it but my input must be wrong.

 

http://www.jgiesen.de/astro/astroJS/siderealClock/

[JagChris]

Ok I figured out what's going on. Perhaps it should label the results? Moon, Saturn etc.

[ClausB]

The UI for ASTRO.BAS is minimal, but complete. For each menu option, it will ask you for necessary inputs and also fill in the table, so you don't have to enter the same data next time, just press RETURN.

 

Yes, it does expect you to remember which planet you asked for. When I was 23 that seemed obvious. Now I'm 63 and I can see your point.

Edited May 29, 2023 by ClausB

[Ricky Spanish]

@ClausB with your Astro program, I chose to locate a planet (Pluto) entered the prerequisites, "LOCATING PLUTO" stopped flashing after a while, and the computer locked, requiring a cold reset. 

[ClausB]

OK, I'll check it out. Do you have 40K?

 

Here is an expanded version, ASTRO.BAP, in BASIC A+. It stores expanded polynomials in disk files for greater accuracy. It auto-boots. Needs 48K.

 

ASTRO.ATR

Edit: be sure to complete menu items 1 and 2 before the others.

 

 

 

Edited May 29, 2023 by ClausB

[Ricky Spanish]

43 minutes ago, ClausB said:

Do you have 40K?

64k + RAMBO XL 256K. Thought low mem was the problem too so I used EXTEND command to store the program in D8. Same thing.

I'll try this new disk, as always, thanks !

[Ricky Spanish]

On 5/29/2023 at 2:57 PM, Ricky Spanish said:

I'll try this new disk, as always, thanks !

Hello @ClausB same thing (for me at least) with the new atr. Needs a cold restart after replicating my above scenario. 

[ClausB]

It happened to me too when I forgot to execute menu items 1 and 2 before the others.

[Ricky Spanish]

1 hour ago, ClausB said:

It happened to me too when I forgot to execute menu items 1 and 2 before the others.

100% my fault. Entered 23 instead of 2023. Works great !

[chevymad]

On 5/29/2023 at 11:32 AM, Ricky Spanish said:

@ClausB with your Astro program, I chose to locate a planet (Pluto) entered the prerequisites, "LOCATING PLUTO" stopped flashing after a while, and the computer locked, requiring a cold reset. 

Because Pluto's not a planet.... LOL kidding of course.