Deciding when the moon passed between aldebaran and mars

Aldebaran has asked for the wisdom of the Perl Monks concerning the following question:

I walked out the home depot last night to a brilliant celestial display, as the moon, aldebaran and mars made a nearly symmetric triangle. I thought, "it looks like the moon has conjoined with mars and is within a day of doing so with aldebaran."

The next day, the moon surprised me by seeming to pass between aldebaran and mars. I would like to use the Astro:: modules to verify that this did indeed happen and when, according to some criterion. What a person thinks he sees can be quite unreliable.

As I begin this, I will note that this project will never be an SSCCE. For one, it's not a contrived example, so the shoe doesn't fit right there. I will take the length I need to represent what I have and what I want. It may be short; it may not be. If that doesn't suit you, do not click the readmore tags expecting otherwise.

I wrote several different versions of an Astro:: script, adding Log4perl in the final one and stepping through with the debugger. That was kind of trip, and I'll list that at the end.

One thing I lack now is a representation for where Aldebaran is. Wiki has it at 4 hr 35 min right ascension and +16 and change for what I assume is degrees above the ecliptic. When I was installing the software, I saw:

  WYANT/Astro-satpass-0.117.tar.gz
  ./Build test -- OK
Running Build install for WYANT/Astro-satpass-0.117.tar.gz
Building Astro-satpass
Installing /usr/local/share/perl/5.30.0/Astro/Coord/ECI.pm
Installing /usr/local/share/perl/5.30.0/Astro/Coord/ECI/Star.pm
[download]

I don't know what that is yet, but that might be the ticket right there.

What I do have is some gutshot data with Mars and the Moon, with an amalgam script 5.astro.pl:

#!/usr/bin/perl 

use Time::Piece;
use Astro::Coord::ECI::Utils 'deg2rad';
use Astro::Coords;
use Astro::Telescope;
use Log::Log4perl;

my $file = '/home/hogan/Documents/hogan/logs/3.log4perl.txt';

# unlink $file or warn "Could not unlink $file: $!";
my $log_conf4 = "/home/hogan/Documents/hogan/logs/conf_files/3.conf";
Log::Log4perl::init($log_conf4);    #info
my $logger = Log::Log4perl->get_logger();
$logger->info("$0");

$logger->info("Object\tAzimuth\tElevation");
$logger->info("Right Ascension\tDeclination ");

for my $name (qw/Mars Moon/) {

  my $planet = Astro::Coords->new( planet => $name );

  $planet->datetime( Time::Piece->new );

  $planet->telescope(
    Astro::Telescope->new(
      Name => 'boise',
      Long => deg2rad(-116.2),    #43.615833, -116.201667
      Lat  => deg2rad(43.61),
      Alt  => 8321,               #meters above sea level boise
    )
  );

  my $az = $planet->az( format => 'deg' );
  my $el = $planet->el( format => 'deg' );
  $logger->info("$name\t$az\t $el");

  my $planet2 = Astro::Coords->new( planet => $name );

  $planet2->datetime( Time::Piece->new );

  my $ra  = $planet2->ra( format => q/deg/ );
  my $dec = $planet2->dec( format => q/deg/ );

  $logger->info("$name\t$ra\t$dec");

}
my $t  = localtime;
my $jd = $t->julian_day;

$logger->info("Time is $t");
$logger->info("Julian day is $jd");
__END__
[download]

This is the conf file for Log4perl. If you get the proper form for the output, then it makes a huge difference for looking at a time series:

######################################################################
+#########
#                              Log::Log4perl Conf                     
+        #
######################################################################
+#########
log4perl.rootLogger              = DEBUG, LOG1, SCREEN
log4perl.appender.SCREEN         = Log::Log4perl::Appender::Screen
log4perl.appender.SCREEN.stderr  = 0
log4perl.appender.SCREEN.layout  = Log::Log4perl::Layout::PatternLayou
+t
log4perl.appender.SCREEN.layout.ConversionPattern = %m %n
log4perl.appender.LOG1           = Log::Log4perl::Appender::File
log4perl.appender.LOG1.filename  = /home/hogan/Documents/hogan/logs/3.
+log4perl.txt
log4perl.appender.LOG1.mode      = append
log4perl.appender.LOG1.layout    = Log::Log4perl::Layout::PatternLayou
+t
log4perl.appender.LOG1.layout.ConversionPattern = %d %p %m %n
[download]

If you would like to replicate this, you will have to change the .filename, unless you happen to be hogan. As far as output, I was very pleased as I went about writing this today, with the log building. Another component of this is going outside and looking every couple hours. That's a way this is not self-contained. We need all kinds of sanity checks with this stuff including peer review and wondering, "did you see it too?" Here's 3.log4perl.txt:

2021/03/19 19:31:51 INFO ./4.astro.pl 
2021/03/19 19:31:51 INFO Object    Azimuth    Elevation 
2021/03/19 19:31:51 INFO Mars    220.365443728883     65.2689423230543
+ 
2021/03/19 19:31:51 INFO Moon    211.599830034082     65.5618916858789
+ 
2021/03/19 19:31:51 INFO Time is Fri Mar 19 19:31:51 2021 
2021/03/19 19:31:51 INFO Julian day is 2459293.56378472 
2021/03/19 22:40:06 INFO ./4.astro.pl 
2021/03/19 22:40:06 INFO Object    Azimuth    Elevation 
2021/03/19 22:40:06 INFO Mars    270.806033806743     34.1750013710903
+ 
2021/03/19 22:40:06 INFO Moon    266.284000787558     36.8694401304625
+ 
2021/03/19 22:40:06 INFO Time is Fri Mar 19 22:40:06 2021 
2021/03/19 22:40:06 INFO Julian day is 2459293.69451389 
2021/03/19 23:35:35 INFO ./5.astro.pl 
2021/03/19 23:35:35 INFO Object    Azimuth    Elevation 
2021/03/19 23:35:35 INFO Right Ascension    Declination  
2021/03/19 23:35:35 INFO Mars    279.88665284031     24.1792258156848 
2021/03/19 23:35:35 INFO 67.2076668140408    23.2786995609773 
2021/03/19 23:35:35 INFO Moon    275.550366714117     27.1395270284972
+ 
2021/03/19 23:35:35 INFO 73.1915415734555    22.2734334102247 
2021/03/19 23:35:35 INFO Time is Fri Mar 19 23:35:35 2021 
2021/03/19 23:35:35 INFO Julian day is 2459293.73304398 
2021/03/19 23:39:06 INFO ./5.astro.pl 
2021/03/19 23:39:06 INFO Object    Azimuth    Elevation 
2021/03/19 23:39:06 INFO Right Ascension    Declination  
2021/03/19 23:39:06 INFO Mars    280.444080455657     23.5521856680493
+ 
2021/03/19 23:39:06 INFO Mars    67.2092465053295    23.2789265197005 
2021/03/19 23:39:06 INFO Moon    276.109507072202     26.5260435839715
+ 
2021/03/19 23:39:06 INFO Moon    73.2365988210088    22.280059131584 
2021/03/19 23:39:06 INFO Time is Fri Mar 19 23:39:06 2021 
2021/03/19 23:39:06 INFO Julian day is 2459293.73548611 
2021/03/20 00:27:38 INFO 5.astro.pl 
2021/03/20 00:27:38 INFO Object    Azimuth    Elevation 
2021/03/20 00:28:10 INFO Right Ascension    Declination  
2021/03/20 00:30:06 INFO Mars    288.303956397801     14.794085544023 
2021/03/20 00:32:59 DEBUG This is debug 
2021/03/20 00:33:58 INFO Mars    67.2338800886927    23.2824828016645 
2021/03/20 00:59:03 INFO Moon    284.638027927888     17.0850686583167
+ 
2021/03/20 01:00:14 INFO Moon    74.2622910906381    22.4512455528347 
2021/03/20 01:00:14 INFO Time is Sat Mar 20 01:00:14 2021 
2021/03/20 01:00:14 INFO Julian day is 2459293.7918287
[download]

The ultimate run was done with the debugger, which I'm tapping my way around with:

$ perl -d 5.astro.pl

Loading DB routines from perl5db.pl version 1.55
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main::(5.astro.pl:9):    my $file = '/home/hogan/Documents/hogan/logs/
+3.log4perl.txt';
  DB<1> n                                                             
+          
main::(5.astro.pl:12):    my $log_conf4 = "/home/hogan/Documents/hogan
+/logs/conf_files/3.conf";
  DB<1> v                                                             
+          
9:    my $file = '/home/hogan/Documents/hogan/logs/3.log4perl.txt';
10     
11     # unlink $file or warn "Could not unlink $file: $!";
12==>    my $log_conf4 = "/home/hogan/Documents/hogan/logs/conf_files/
+3.conf";
13:    Log::Log4perl::init($log_conf4);    #info
14:    my $logger = Log::Log4perl->get_logger();
...

main::(5.astro.pl:39):      my $planet2 = Astro::Coords->new( planet =
+> $name );
  DB<6> $logger->debug( "This is debug");                             
+          
This is debug 
...
  DB<8> .                                                             
+          
main::(5.astro.pl:26):      $planet->telescope(
main::(5.astro.pl:27):        Astro::Telescope->new(
main::(5.astro.pl:28):          Name => 'boise',
main::(5.astro.pl:29):          Long => deg2rad(-116.2),    #43.615833
+, -116.201667
main::(5.astro.pl:30):          Lat  => deg2rad(43.61),
main::(5.astro.pl:31):          Alt  => 8321,               #meters ab
+ove sea level boise
main::(5.astro.pl:32):        )
main::(5.astro.pl:33):      );
  DB<8> s                                                             
+          
Astro::Coord::ECI::Utils::deg2rad(/usr/local/share/perl/5.30.0/Astro/C
+oord/ECI/Utils.pm:545):
545:    sub deg2rad { return defined $_[0] ? $_[0] * PI / 180 : undef 
+}
...
  DB<8> n                                                             
+          
Astro::Telescope::new(/usr/local/share/perl/5.30.0/Astro/Telescope.pm:
+182):
182:      my $proto = shift;
  DB<8> n                                                             
+          
Astro::Telescope::new(/usr/local/share/perl/5.30.0/Astro/Telescope.pm:
+183):
183:      my $class = ref($proto) || $proto;
  DB<8> v                                                             
+          
180     
181     sub new {
182:      my $proto = shift;
183==>      my $class = ref($proto) || $proto;
184     
185:      return undef unless @_;
186     
187       # Create the new object
188:      my $tel = bless {}, $class;
189     
  DB<8> b 188                                                         
+          
  DB<9> c                                                             
+          
Astro::Telescope::new(/usr/local/share/perl/5.30.0/Astro/Telescope.pm:
+188):
188:      my $tel = bless {}, $class;
  DB<9> n                                                             
+          
Astro::Telescope::new(/usr/local/share/perl/5.30.0/Astro/Telescope.pm:
+192):
192:      $tel->_configure( @_ ) or return undef;
  DB<9> v                                                             
+          
189     
190       # Configure it with the supplied telescope name
191       # or other arguments
192==>      $tel->_configure( @_ ) or return undef;
193     
194:      return $tel;
195     }
196     
197     =back
198     
  DB<9> p @_                                                          
+          
NameboiseLong-2.02807259081741Lat0.761138086794727Alt8321
 ...
  DB<10> v                                                            
+          
217     =cut
218     
219     sub new {
220==>      my $class = shift;
221     
222:      my %args = @_;
223     
224:      my $obj;
225     
226       # Always try for a planet object first if $args{planet} is u
+sed
  DB<10> b 224                                                        
+          
  DB<11> c                                                            
+          
Astro::Coords::new(/usr/local/share/perl/5.30.0/Astro/Coords.pm:224):
224:      my $obj;
  DB<11> p @_                                                         
+          
planetMoon
  DB<12> c                                                            
+          
Moon    74.2622910906381    22.4512455528347 
Time is Sat Mar 20 01:00:14 2021 
Julian day is 2459293.7918287 
Debugged program terminated.  Use q to quit or R to restart,
use o inhibit_exit to avoid stopping after program termination,
h q, h R or h o to get additional info.
  DB<12> q
[download]

Anyways, so that's as far as make it tonight.

Thank you for your comments.

Comment on Deciding when the moon passed between aldebaran and mars Select or Download Code

Replies are listed 'Best First'.
Re: Deciding when the moon passed between aldebaran and mars by Aldebaran (Curate) on Mar 21, 2021 at 07:14 UTC
One thing I lack now is a representation for where Aldebaran is. I tried writing a script that used the example in Star.pm. In it, it required me to turn right ascension into radians, and after the script pooped out, I realized that all I needed to start making comparisons was its fixed value in radians. `$ ./7.astro.pl ./7.astro.pl Name Right Ascension Declination Mars 1.18463017264379 0.407948808088123 Moon 1.51448031651065 0.422740932680421 Aldeb 1.20392811802569 0.288139315093836 Time is Sun Mar 21 00:39:59 2021 Julian day is 2459294.7777662 $ pt 7.astro.pl $ cat 7.astro.pl <-I do this to be correct and use STDOUT to list reli +ably` [download] #!/usr/bin/perl use Time::Piece; use Astro::Coord::ECI::Utils 'deg2rad'; use Astro::Coords; use Log::Log4perl; my $file = '/home/hogan/Documents/hogan/logs/3.log4perl.txt'; # unlink $file or warn "Could not unlink $file: $!"; my $log_conf4 = "/home/hogan/Documents/hogan/logs/conf_files/3.conf"; Log::Log4perl::init($log_conf4); #info my $logger = Log::Log4perl->get_logger(); $logger->info("$0"); $logger->info("Name\tRight Ascension\t\tDeclination"); for my $name (qw/Mars Moon/) { my $planet2 = Astro::Coords->new( planet => $name ); $planet2->datetime( Time::Piece->new ); my $ra = $planet2->ra( format => q/rad/ ); my $dec = $planet2->dec( format => q/rad/ ); $logger->info("$name\t$ra\t$dec"); } my $aldeb_ra_degrees = 68.98; my $aldeb_ra_radians = deg2rad($aldeb_ra_degrees); my $aldeb_declination_degrees = 16.509166666667; my $aldeb_dec_radians = deg2rad($aldeb_declination_degrees); $logger->info("Aldeb\t$aldeb_ra_radians\t$aldeb_dec_radians "); my $t = localtime; my $jd = $t->julian_day; $logger->info("Time is $t"); $logger->info("Julian day is $jd"); __END__ [download] So, the data is bunching together well, but I'm not completely sure how I'd go about figuring out when something crosses between. For me, it's a tantalizing triangle. I would think that we should think of these creatures as two-vectors of radians. Then my question now is this: if these are 3 traveling 2-vectors (one is stationary for this script), how do I write a function to calculate betweenness? It seems clear to me that I would need to invoke a telescope method. I also wonder if everyone in the world could have had a chance to see this (less light pollution)?	[reply] [d/l] [select]
Re understanding values at vernal equinox by Aldebaran (Curate) on Mar 21, 2021 at 23:45 UTC
I just happen to be making astronomical calculations in perl and noticing that the sun is really near 0 right ascension and declination. Hmm. That would be the vernal equinox, right? I always like to calculate things like this exactly if I happen to have the time and a nearby laptop. I'm getting output I don't understand, so I think I'm in a better place to ask a cohesive question. What's more, I think I can get to it without needing to resort to readmore tags. I found an old thread where haukex had helped me figure out some of this: Re: calculate length of day as function of space at onset of fall, and started folding in the old code into the new. I write some really primitive-looking code looking back, but it's my learning on display. Out of this I made a githubpull request, simply to try to understand how github works, and I really don't get it still, which defines me clearly as an intermediate perl user that I am struggling with it. This is what I had some code at github that calculates equinoxes, sunsets, meridians. Anyways, so I start chopping that up and am left 3 lines, and then I hardcode the year: `use Astro::Utils; my $spring = calculate_equinox( 'mar', 'utc', '2021' ); $logger->info("spring begins $spring");` [download] I'll list output, source and then have a couple questions. `$ ./3.vernal.pl ./3.vernal.pl Name Right Ascension Declination Mars 1.19220473652282 0.409015700183571 Moon 1.6536783961676 0.442537954264476 Sun 0.0202246733370893 0.00876435085335973 Aldeb 1.20392811802569 0.288139315093836 Time is Sun Mar 21 17:03:18 2021 Julian day is 2459295.460625 Sun set is Mon Mar 22 01:58:54 2021 Astro::Coord::ECI=HASH(0x560eda31aa70) spring begins 2021-03-20 09:37:05 $ cat 3.vernal.pl` [download] #!/usr/bin/perl use Time::Piece; use Astro::Coord::ECI::Utils 'deg2rad'; use Astro::Coords; use Log::Log4perl; use 5.030; my $file = '/home/hogan/Documents/hogan/logs/3.log4perl.txt'; unlink $file or warn "Could not unlink $file: $!"; my $log_conf4 = "/home/hogan/Documents/hogan/logs/conf_files/3.conf"; Log::Log4perl::init($log_conf4); #info my $logger = Log::Log4perl->get_logger(); $logger->info("$0"); $logger->info("Name\tRight Ascension\t\tDeclination"); for my $name (qw/Mars Moon Sun/) { my $planet2 = Astro::Coords->new( planet => $name ); $planet2->datetime( Time::Piece->new ); my $ra = $planet2->ra( format => q/rad/ ); my $dec = $planet2->dec( format => q/rad/ ); $logger->info("$name\t$ra\t$dec"); } ## declare values and tailor to what these routines expect... my $aldeb_ra_degrees = 68.98; my $aldeb_ra_radians = deg2rad($aldeb_ra_degrees); my $aldeb_declination_degrees = 16.509166666667; my $aldeb_dec_radians = deg2rad($aldeb_declination_degrees); my $local_lat = deg2rad(43.6135); # +Radians my $local_long = deg2rad(-116.20345); # +Radians my $local_alt = 8321 / 1000; # +Kilometers $logger->info("Aldeb\t$aldeb_ra_radians\t$aldeb_dec_radians "); my $t = localtime; my $jd = $t->julian_day; $logger->info("Time is $t"); $logger->info("Julian day is $jd"); use Astro::Coord::ECI::Sun; my $sun = Astro::Coord::ECI::Sun->new(); my $sta = Astro::Coord::ECI->universal( time() ) ->geodetic( $local_lat, $local_long, $local_alt ); my ( $time, $rise ) = $sta->next_elevation($sun); my $string = "Sun @{[$rise ? 'rise' : 'set']} is " . scalar gmtime $time . " UT\n +"; $logger->info("$string"); $logger->debug("$sta"); # calculate begin of spring use Astro::Utils; my $spring = calculate_equinox( 'mar', 'utc', '2021' ); $logger->info("spring begins $spring"); __END__ $ [download] As I look at the data, does it not say that spring has already sprung? Here's question 1: Is the value for $spring correct? If $spring is correct, then has spring sprung? If so, why are the values for the sun's declination and right ascension still so unzeroish? Thanks for your comments,	[reply] [d/l] [select]