PowerShell - An weird issue related to convertfrom-string - arrays

Question

So I am trying to get average lengths of the four seasons in the 21st century using PowerShell as a self-imposed programming challenge.
My idea is to get values from a text file, create a [PSCustomObject] and assign values to its noteproperties each line, add year to the date and convert the dates to [datetime] and add to another array, then loop through the second array using index and get season length using new-timespan and add to a third array, and measure-object third array, forgive me if this may sound confusing in English but it really is very simple in code.
Now I get the dates of equinoxes and solstices from here:Solstices and Equinoxes: 2001 to 2100
Using Notepad++ to format the dates I got this:
2001 Mar 20 13:31 Jun 21 07:38 Sep 22 23:05 Dec 21 19:22
2002 Mar 20 19:16 Jun 21 13:25 Sep 23 04:56 Dec 22 01:15
2003 Mar 21 01:00 Jun 21 19:11 Sep 23 10:47 Dec 22 07:04
2004 Mar 20 06:49 Jun 21 00:57 Sep 22 16:30 Dec 21 12:42
2005 Mar 20 12:34 Jun 21 06:46 Sep 22 22:23 Dec 21 18:35
2006 Mar 20 18:25 Jun 21 12:26 Sep 23 04:04 Dec 22 00:22
2007 Mar 21 00:07 Jun 21 18:06 Sep 23 09:51 Dec 22 06:08
2008 Mar 20 05:49 Jun 21 00:00 Sep 22 15:45 Dec 21 12:04
2009 Mar 20 11:44 Jun 21 05:45 Sep 22 21:18 Dec 21 17:47
2010 Mar 20 17:32 Jun 21 11:28 Sep 23 03:09 Dec 21 23:38
2011 Mar 20 23:21 Jun 21 17:16 Sep 23 09:05 Dec 22 05:30
2012 Mar 20 05:15 Jun 20 23:08 Sep 22 14:49 Dec 21 11:12
2013 Mar 20 11:02 Jun 21 05:04 Sep 22 20:44 Dec 21 17:11
2014 Mar 20 16:57 Jun 21 10:52 Sep 23 02:30 Dec 21 23:03
2015 Mar 20 22:45 Jun 21 16:38 Sep 23 08:20 Dec 22 04:48
2016 Mar 20 04:31 Jun 20 22:35 Sep 22 14:21 Dec 21 10:45
2017 Mar 20 10:29 Jun 21 04:25 Sep 22 20:02 Dec 21 16:29
2018 Mar 20 16:15 Jun 21 10:07 Sep 23 01:54 Dec 21 22:22
2019 Mar 20 21:58 Jun 21 15:54 Sep 23 07:50 Dec 22 04:19
2020 Mar 20 03:50 Jun 20 21:43 Sep 22 13:31 Dec 21 10:03
2021 Mar 20 09:37 Jun 21 03:32 Sep 22 19:21 Dec 21 15:59
2022 Mar 20 15:33 Jun 21 09:14 Sep 23 01:04 Dec 21 21:48
2023 Mar 20 21:25 Jun 21 14:58 Sep 23 06:50 Dec 22 03:28
2024 Mar 20 03:07 Jun 20 20:51 Sep 22 12:44 Dec 21 09:20
2025 Mar 20 09:02 Jun 21 02:42 Sep 22 18:20 Dec 21 15:03
2026 Mar 20 14:46 Jun 21 08:25 Sep 23 00:06 Dec 21 20:50
2027 Mar 20 20:25 Jun 21 14:11 Sep 23 06:02 Dec 22 02:43
2028 Mar 20 02:17 Jun 20 20:02 Sep 22 11:45 Dec 21 08:20
2029 Mar 20 08:01 Jun 21 01:48 Sep 22 17:37 Dec 21 14:14
2030 Mar 20 13:51 Jun 21 07:31 Sep 22 23:27 Dec 21 20:09
2031 Mar 20 19:41 Jun 21 13:17 Sep 23 05:15 Dec 22 01:56
2032 Mar 20 01:23 Jun 20 19:09 Sep 22 11:11 Dec 21 07:57
2033 Mar 20 07:23 Jun 21 01:01 Sep 22 16:52 Dec 21 13:45
2034 Mar 20 13:18 Jun 21 06:45 Sep 22 22:41 Dec 21 19:35
2035 Mar 20 19:03 Jun 21 12:33 Sep 23 04:39 Dec 22 01:31
2036 Mar 20 01:02 Jun 20 18:31 Sep 22 10:23 Dec 21 07:12
2037 Mar 20 06:50 Jun 21 00:22 Sep 22 16:13 Dec 21 13:08
2038 Mar 20 12:40 Jun 21 06:09 Sep 22 22:02 Dec 21 19:01
2039 Mar 20 18:32 Jun 21 11:58 Sep 23 03:50 Dec 22 00:41
2040 Mar 20 00:11 Jun 20 17:46 Sep 22 09:44 Dec 21 06:33
2041 Mar 20 06:07 Jun 20 23:37 Sep 22 15:27 Dec 21 12:19
2042 Mar 20 11:53 Jun 21 05:16 Sep 22 21:11 Dec 21 18:04
2043 Mar 20 17:29 Jun 21 10:59 Sep 23 03:07 Dec 22 00:02
2044 Mar 19 23:20 Jun 20 16:50 Sep 22 08:47 Dec 21 05:43
2045 Mar 20 05:08 Jun 20 22:34 Sep 22 14:33 Dec 21 11:36
2046 Mar 20 10:58 Jun 21 04:15 Sep 22 20:22 Dec 21 17:28
2047 Mar 20 16:52 Jun 21 10:02 Sep 23 02:07 Dec 21 23:07
2048 Mar 19 22:34 Jun 20 15:54 Sep 22 08:01 Dec 21 05:02
2049 Mar 20 04:28 Jun 20 21:47 Sep 22 13:42 Dec 21 10:51
2050 Mar 20 10:20 Jun 21 03:33 Sep 22 19:29 Dec 21 16:39
2051 Mar 20 15:58 Jun 21 09:17 Sep 23 01:26 Dec 21 22:33
2052 Mar 19 21:56 Jun 20 15:16 Sep 22 07:16 Dec 21 04:18
2053 Mar 20 03:46 Jun 20 21:03 Sep 22 13:05 Dec 21 10:09
2054 Mar 20 09:35 Jun 21 02:47 Sep 22 19:00 Dec 21 16:10
2055 Mar 20 15:28 Jun 21 08:39 Sep 23 00:48 Dec 21 21:56
2056 Mar 19 21:11 Jun 20 14:29 Sep 22 06:40 Dec 21 03:52
2057 Mar 20 03:08 Jun 20 20:19 Sep 22 12:23 Dec 21 09:42
2058 Mar 20 09:04 Jun 21 02:03 Sep 22 18:07 Dec 21 15:24
2059 Mar 20 14:44 Jun 21 07:47 Sep 23 00:03 Dec 21 21:18
2060 Mar 19 20:37 Jun 20 13:44 Sep 22 05:47 Dec 21 03:00
2061 Mar 20 02:26 Jun 20 19:33 Sep 22 11:31 Dec 21 08:49
2062 Mar 20 08:07 Jun 21 01:10 Sep 22 17:19 Dec 21 14:42
2063 Mar 20 13:59 Jun 21 07:02 Sep 22 23:08 Dec 21 20:22
2064 Mar 19 19:40 Jun 20 12:47 Sep 22 04:58 Dec 21 02:10
2065 Mar 20 01:27 Jun 20 18:31 Sep 22 10:41 Dec 21 07:59
2066 Mar 20 07:19 Jun 21 00:16 Sep 22 16:27 Dec 21 13:45
2067 Mar 20 12:55 Jun 21 05:56 Sep 22 22:20 Dec 21 19:44
2068 Mar 19 18:51 Jun 20 11:55 Sep 22 04:09 Dec 21 01:34
2069 Mar 20 00:44 Jun 20 17:40 Sep 22 09:51 Dec 21 07:21
2070 Mar 20 06:35 Jun 20 23:22 Sep 22 15:45 Dec 21 13:19
2071 Mar 20 12:36 Jun 21 05:21 Sep 22 21:39 Dec 21 19:05
2072 Mar 19 18:19 Jun 20 11:12 Sep 22 03:26 Dec 21 00:54
2073 Mar 20 00:12 Jun 20 17:06 Sep 22 09:14 Dec 21 06:50
2074 Mar 20 06:09 Jun 20 22:59 Sep 22 15:04 Dec 21 12:36
2075 Mar 20 11:48 Jun 21 04:41 Sep 22 21:00 Dec 21 18:28
2076 Mar 19 17:37 Jun 20 10:35 Sep 22 02:48 Dec 21 00:12
2077 Mar 19 23:30 Jun 20 16:23 Sep 22 08:35 Dec 21 06:00
2078 Mar 20 05:11 Jun 20 21:58 Sep 22 14:25 Dec 21 11:59
2079 Mar 20 11:03 Jun 21 03:51 Sep 22 20:15 Dec 21 17:46
2080 Mar 19 16:43 Jun 20 09:33 Sep 22 01:55 Dec 20 23:31
2081 Mar 19 22:34 Jun 20 15:16 Sep 22 07:38 Dec 21 05:22
2082 Mar 20 04:32 Jun 20 21:04 Sep 22 13:24 Dec 21 11:06
2083 Mar 20 10:08 Jun 21 02:41 Sep 22 19:10 Dec 21 16:51
2084 Mar 19 15:58 Jun 20 08:39 Sep 22 00:58 Dec 20 22:40
2085 Mar 19 21:53 Jun 20 14:33 Sep 22 06:43 Dec 21 04:29
2086 Mar 20 03:36 Jun 20 20:11 Sep 22 12:33 Dec 21 10:24
2087 Mar 20 09:27 Jun 21 02:05 Sep 22 18:27 Dec 21 16:07
2088 Mar 19 15:16 Jun 20 07:57 Sep 22 00:18 Dec 20 21:56
2089 Mar 19 21:07 Jun 20 13:43 Sep 22 06:07 Dec 21 03:53
2090 Mar 20 03:03 Jun 20 19:37 Sep 22 12:01 Dec 21 09:45
2091 Mar 20 08:40 Jun 21 01:17 Sep 22 17:49 Dec 21 15:37
2092 Mar 19 14:33 Jun 20 07:14 Sep 21 23:41 Dec 20 21:31
2093 Mar 19 20:35 Jun 20 13:08 Sep 22 05:30 Dec 21 03:21
2094 Mar 20 02:20 Jun 20 18:40 Sep 22 11:15 Dec 21 09:11
2095 Mar 20 08:14 Jun 21 00:38 Sep 22 17:10 Dec 21 15:00
2096 Mar 19 14:03 Jun 20 06:31 Sep 21 22:55 Dec 20 20:46
2097 Mar 19 19:49 Jun 20 12:14 Sep 22 04:37 Dec 21 02:38
2098 Mar 20 01:38 Jun 20 18:01 Sep 22 10:22 Dec 21 08:19
2099 Mar 20 07:17 Jun 20 23:41 Sep 22 16:10 Dec 21 14:04
2100 Mar 20 13:04 Jun 21 05:32 Sep 22 22:00 Dec 21 19:51
Then I used these codes on PowerShell 7.1 x64 on Windows 10:
$timetable = Get-Content .\Desktop\Equinox-Solstice.txt | Convertfrom-String -Templatefile .\Desktop\template.txt
$count=$timetable.count
$timetable1=#()
for ($i=0;$i -lt $count;$i++) {
$year=[string]$timetable[$i].year
$mequi=[datetime]($year+" "+$timetable[$i].marequi)
$jsols=[datetime]($year+" "+$timetable[$i].junsols)
$sequi=[datetime]($year+" "+$timetable[$i].sepequi)
$dsols=[datetime]($year+" "+$timetable[$i].decsols)
$timetable1+=[pscustomobject]#{year=$year;mequi=$mequi;jsols=$jsols;sequi=$sequi;dsols=$dsols}
}
With this as template:
{[int]year*:2001} {[string]marequi:Mar 20 13:31} {[string]junsols:Jun 21 07:38} {[string]sepequi:Sep 22 23:05} {[string]decsols:Dec 21 19:22}
{[int]year*:2002} {[string]marequi:Mar 20 19:16} {[string]junsols:Jun 21 13:25} {[string]sepequi:Sep 23 04:56} {[string]decsols:Dec 22 01:15}
{[int]year*:2003} {[string]marequi:Mar 21 01:00} {[string]junsols:Jun 21 19:11} {[string]sepequi:Sep 23 10:47} {[string]decsols:Dec 22 07:04}
{[int]year*:2004} {[string]marequi:Mar 20 06:49} {[string]junsols:Jun 21 00:57} {[string]sepequi:Sep 22 16:30} {[string]decsols:Dec 21 12:42}
{[int]year*:2005} {[string]marequi:Mar 20 12:34} {[string]junsols:Jun 21 06:46} {[string]sepequi:Sep 22 22:23} {[string]decsols:Dec 21 18:35}
{[int]year*:2006} {[string]marequi:Mar 20 18:25} {[string]junsols:Jun 21 12:26} {[string]sepequi:Sep 23 04:04} {[string]decsols:Dec 22 00:22}
{[int]year*:2007} {[string]marequi:Mar 21 00:07} {[string]junsols:Jun 21 18:06} {[string]sepequi:Sep 23 09:51} {[string]decsols:Dec 22 06:08}
{[int]year*:2008} {[string]marequi:Mar 20 05:49} {[string]junsols:Jun 21 00:00} {[string]sepequi:Sep 22 15:45} {[string]decsols:Dec 21 12:04}
{[int]year*:2009} {[string]marequi:Mar 20 11:44} {[string]junsols:Jun 21 05:45} {[string]sepequi:Sep 22 21:18} {[string]decsols:Dec 21 17:47}
{[int]year*:2010} {[string]marequi:Mar 20 17:32} {[string]junsols:Jun 21 11:28} {[string]sepequi:Sep 23 03:09} {[string]decsols:Dec 21 23:38}
And when I ran the command, I got lots of error messages, all of them are like this:
InvalidArgument:
Line |
3 | $mequi=[datetime]($year+" "+$timetable[$i].marequi)
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| Cannot convert value "2093 " to type "System.DateTime". Error: "String '2093 ' was not recognized as a valid DateTime."
I have checked thoroughly and found all of them are from $mequi, which stands for March Equinox, I realised the dates must be missing, then I typed $timetable and confirmed lots of March Equinox dates are missing, and only March Equinox dates are missing, I then used this command:
for($i=0;$i -lt 99;$i++){if ($timetable[$i].marequi -eq $null){$i}}
And found out 46 of them are missing, but the dates in other 3 categories are not missing, just March Equinox, the indexes of the missing dates are the following:
11, 15, 19, 23, 27, 31, 35, 39, 40, 43, 44, 47, 48, 51, 52, 55, 56, 59, 60, 63, 64, 67, 68, 69, 71, 72, 73, 75, 76, 77, 79, 80, 81, 83, 84, 85, 87, 88, 89, 91, 92, 93, 95, 96, 97, 98
Any ideas? Can someone help me, please?
Update3: So I used the complete code:
$timetable = Get-Content .\Desktop\Equinox-Solstice.txt | Convertfrom-String -Templatefile .\Desktop\template.txt
$count=$timetable.count
[array]$timetable1 = 0..99 | foreach-object {
$year=[string]$timetable[$_].year
$mequi=[datetime]($year+" "+$timetable[$_].marequi)
$jsols=[datetime]($year+" "+$timetable[$_].junsols)
$sequi=[datetime]($year+" "+$timetable[$_].sepequi)
$dsols=[datetime]($year+" "+$timetable[$_].decsols)
[pscustomobject]#{year=$year;mequi=$mequi;jsols=$jsols;sequi=$sequi;dsols=$dsols}
}
[array]$seasons=0..98 | foreach-object {
$year=$timetable1[$_].year
$spring=[double](New-Timespan -Start $timetable1[$_].mequi -End $timetable1[$_].jsols).totaldays
$summer=[double](New-Timespan -Start $timetable1[$_].jsols -End $timetable1[$_].sequi).totaldays
$autumn=[double](New-Timespan -Start $timetable1[$_].sequi -End $timetable1[$_].dsols).totaldays
$winter=[double](New-Timespan -Start $timetable1[$_].dsols -End $timetable1[$_+1].mequi).totaldays
[pscustomobject]#{year=$year;spring=$spring;summer=$summer;autumn=$autumn;winter=$winter}
}
$meanspring=($seasons.spring | Measure-Object -Average).average
$meansummer=($seasons.summer | Measure-Object -Average).average
$meanautumn=($seasons.autumn | Measure-Object -Average).average
$meanwinter=($seasons.winter | Measure-Object -Average).average
$meanyear=$meanspring+$meansummer+$meanautumn+$meanwinter
Write-Host "Mean Spring Length: $meanspring days, Mean Summer Length: $meansummer days, Mean Autumn Length: $meanautumn days, Mean Winter Length: $meanwinter days, Mean Solar Year Length: $meanyear days"
And this is what I got:
Mean Spring Length: 92.7203563411897 days, Mean Summer Length: 93.6684764309764 days, Mean Autumn Length: 89.8785914702581 days, Mean Winter Length: 88.9748106060606 days, Mean Solar Year Length: 365.242234848485 days.
Update: I am now editing the question because I want to share a better method.
With a little more effort at find and replace in Notepad++ I was able to obtain this:
"year","marequi","junsols","sepequi","decsols"
"2001","Mar 20 13:31","Jun 21 07:38","Sep 22 23:05","Dec 21 19:22"
"2002","Mar 20 19:16","Jun 21 13:25","Sep 23 04:56","Dec 22 01:15"
"2003","Mar 21 01:00","Jun 21 19:11","Sep 23 10:47","Dec 22 07:04"
"2004","Mar 20 06:49","Jun 21 00:57","Sep 22 16:30","Dec 21 12:42"
"2005","Mar 20 12:34","Jun 21 06:46","Sep 22 22:23","Dec 21 18:35"
"2006","Mar 20 18:25","Jun 21 12:26","Sep 23 04:04","Dec 22 00:22"
"2007","Mar 21 00:07","Jun 21 18:06","Sep 23 09:51","Dec 22 06:08"
"2008","Mar 20 05:49","Jun 21 00:00","Sep 22 15:45","Dec 21 12:04"
"2009","Mar 20 11:44","Jun 21 05:45","Sep 22 21:18","Dec 21 17:47"
"2010","Mar 20 17:32","Jun 21 11:28","Sep 23 03:09","Dec 21 23:38"
"2011","Mar 20 23:21","Jun 21 17:16","Sep 23 09:05","Dec 22 05:30"
"2012","Mar 20 05:15","Jun 20 23:08","Sep 22 14:49","Dec 21 11:12"
"2013","Mar 20 11:02","Jun 21 05:04","Sep 22 20:44","Dec 21 17:11"
"2014","Mar 20 16:57","Jun 21 10:52","Sep 23 02:30","Dec 21 23:03"
"2015","Mar 20 22:45","Jun 21 16:38","Sep 23 08:20","Dec 22 04:48"
"2016","Mar 20 04:31","Jun 20 22:35","Sep 22 14:21","Dec 21 10:45"
"2017","Mar 20 10:29","Jun 21 04:25","Sep 22 20:02","Dec 21 16:29"
"2018","Mar 20 16:15","Jun 21 10:07","Sep 23 01:54","Dec 21 22:22"
"2019","Mar 20 21:58","Jun 21 15:54","Sep 23 07:50","Dec 22 04:19"
"2020","Mar 20 03:50","Jun 20 21:43","Sep 22 13:31","Dec 21 10:03"
"2021","Mar 20 09:37","Jun 21 03:32","Sep 22 19:21","Dec 21 15:59"
"2022","Mar 20 15:33","Jun 21 09:14","Sep 23 01:04","Dec 21 21:48"
"2023","Mar 20 21:25","Jun 21 14:58","Sep 23 06:50","Dec 22 03:28"
"2024","Mar 20 03:07","Jun 20 20:51","Sep 22 12:44","Dec 21 09:20"
"2025","Mar 20 09:02","Jun 21 02:42","Sep 22 18:20","Dec 21 15:03"
"2026","Mar 20 14:46","Jun 21 08:25","Sep 23 00:06","Dec 21 20:50"
"2027","Mar 20 20:25","Jun 21 14:11","Sep 23 06:02","Dec 22 02:43"
"2028","Mar 20 02:17","Jun 20 20:02","Sep 22 11:45","Dec 21 08:20"
"2029","Mar 20 08:01","Jun 21 01:48","Sep 22 17:37","Dec 21 14:14"
"2030","Mar 20 13:51","Jun 21 07:31","Sep 22 23:27","Dec 21 20:09"
"2031","Mar 20 19:41","Jun 21 13:17","Sep 23 05:15","Dec 22 01:56"
"2032","Mar 20 01:23","Jun 20 19:09","Sep 22 11:11","Dec 21 07:57"
"2033","Mar 20 07:23","Jun 21 01:01","Sep 22 16:52","Dec 21 13:45"
"2034","Mar 20 13:18","Jun 21 06:45","Sep 22 22:41","Dec 21 19:35"
"2035","Mar 20 19:03","Jun 21 12:33","Sep 23 04:39","Dec 22 01:31"
"2036","Mar 20 01:02","Jun 20 18:31","Sep 22 10:23","Dec 21 07:12"
"2037","Mar 20 06:50","Jun 21 00:22","Sep 22 16:13","Dec 21 13:08"
"2038","Mar 20 12:40","Jun 21 06:09","Sep 22 22:02","Dec 21 19:01"
"2039","Mar 20 18:32","Jun 21 11:58","Sep 23 03:50","Dec 22 00:41"
"2040","Mar 20 00:11","Jun 20 17:46","Sep 22 09:44","Dec 21 06:33"
"2041","Mar 20 06:07","Jun 20 23:37","Sep 22 15:27","Dec 21 12:19"
"2042","Mar 20 11:53","Jun 21 05:16","Sep 22 21:11","Dec 21 18:04"
"2043","Mar 20 17:29","Jun 21 10:59","Sep 23 03:07","Dec 22 00:02"
"2044","Mar 19 23:20","Jun 20 16:50","Sep 22 08:47","Dec 21 05:43"
"2045","Mar 20 05:08","Jun 20 22:34","Sep 22 14:33","Dec 21 11:36"
"2046","Mar 20 10:58","Jun 21 04:15","Sep 22 20:22","Dec 21 17:28"
"2047","Mar 20 16:52","Jun 21 10:02","Sep 23 02:07","Dec 21 23:07"
"2048","Mar 19 22:34","Jun 20 15:54","Sep 22 08:01","Dec 21 05:02"
"2049","Mar 20 04:28","Jun 20 21:47","Sep 22 13:42","Dec 21 10:51"
"2050","Mar 20 10:20","Jun 21 03:33","Sep 22 19:29","Dec 21 16:39"
"2051","Mar 20 15:58","Jun 21 09:17","Sep 23 01:26","Dec 21 22:33"
"2052","Mar 19 21:56","Jun 20 15:16","Sep 22 07:16","Dec 21 04:18"
"2053","Mar 20 03:46","Jun 20 21:03","Sep 22 13:05","Dec 21 10:09"
"2054","Mar 20 09:35","Jun 21 02:47","Sep 22 19:00","Dec 21 16:10"
"2055","Mar 20 15:28","Jun 21 08:39","Sep 23 00:48","Dec 21 21:56"
"2056","Mar 19 21:11","Jun 20 14:29","Sep 22 06:40","Dec 21 03:52"
"2057","Mar 20 03:08","Jun 20 20:19","Sep 22 12:23","Dec 21 09:42"
"2058","Mar 20 09:04","Jun 21 02:03","Sep 22 18:07","Dec 21 15:24"
"2059","Mar 20 14:44","Jun 21 07:47","Sep 23 00:03","Dec 21 21:18"
"2060","Mar 19 20:37","Jun 20 13:44","Sep 22 05:47","Dec 21 03:00"
"2061","Mar 20 02:26","Jun 20 19:33","Sep 22 11:31","Dec 21 08:49"
"2062","Mar 20 08:07","Jun 21 01:10","Sep 22 17:19","Dec 21 14:42"
"2063","Mar 20 13:59","Jun 21 07:02","Sep 22 23:08","Dec 21 20:22"
"2064","Mar 19 19:40","Jun 20 12:47","Sep 22 04:58","Dec 21 02:10"
"2065","Mar 20 01:27","Jun 20 18:31","Sep 22 10:41","Dec 21 07:59"
"2066","Mar 20 07:19","Jun 21 00:16","Sep 22 16:27","Dec 21 13:45"
"2067","Mar 20 12:55","Jun 21 05:56","Sep 22 22:20","Dec 21 19:44"
"2068","Mar 19 18:51","Jun 20 11:55","Sep 22 04:09","Dec 21 01:34"
"2069","Mar 20 00:44","Jun 20 17:40","Sep 22 09:51","Dec 21 07:21"
"2070","Mar 20 06:35","Jun 20 23:22","Sep 22 15:45","Dec 21 13:19"
"2071","Mar 20 12:36","Jun 21 05:21","Sep 22 21:39","Dec 21 19:05"
"2072","Mar 19 18:19","Jun 20 11:12","Sep 22 03:26","Dec 21 00:54"
"2073","Mar 20 00:12","Jun 20 17:06","Sep 22 09:14","Dec 21 06:50"
"2074","Mar 20 06:09","Jun 20 22:59","Sep 22 15:04","Dec 21 12:36"
"2075","Mar 20 11:48","Jun 21 04:41","Sep 22 21:00","Dec 21 18:28"
"2076","Mar 19 17:37","Jun 20 10:35","Sep 22 02:48","Dec 21 00:12"
"2077","Mar 19 23:30","Jun 20 16:23","Sep 22 08:35","Dec 21 06:00"
"2078","Mar 20 05:11","Jun 20 21:58","Sep 22 14:25","Dec 21 11:59"
"2079","Mar 20 11:03","Jun 21 03:51","Sep 22 20:15","Dec 21 17:46"
"2080","Mar 19 16:43","Jun 20 09:33","Sep 22 01:55","Dec 20 23:31"
"2081","Mar 19 22:34","Jun 20 15:16","Sep 22 07:38","Dec 21 05:22"
"2082","Mar 20 04:32","Jun 20 21:04","Sep 22 13:24","Dec 21 11:06"
"2083","Mar 20 10:08","Jun 21 02:41","Sep 22 19:10","Dec 21 16:51"
"2084","Mar 19 15:58","Jun 20 08:39","Sep 22 00:58","Dec 20 22:40"
"2085","Mar 19 21:53","Jun 20 14:33","Sep 22 06:43","Dec 21 04:29"
"2086","Mar 20 03:36","Jun 20 20:11","Sep 22 12:33","Dec 21 10:24"
"2087","Mar 20 09:27","Jun 21 02:05","Sep 22 18:27","Dec 21 16:07"
"2088","Mar 19 15:16","Jun 20 07:57","Sep 22 00:18","Dec 20 21:56"
"2089","Mar 19 21:07","Jun 20 13:43","Sep 22 06:07","Dec 21 03:53"
"2090","Mar 20 03:03","Jun 20 19:37","Sep 22 12:01","Dec 21 09:45"
"2091","Mar 20 08:40","Jun 21 01:17","Sep 22 17:49","Dec 21 15:37"
"2092","Mar 19 14:33","Jun 20 07:14","Sep 21 23:41","Dec 20 21:31"
"2093","Mar 19 20:35","Jun 20 13:08","Sep 22 05:30","Dec 21 03:21"
"2094","Mar 20 02:20","Jun 20 18:40","Sep 22 11:15","Dec 21 09:11"
"2095","Mar 20 08:14","Jun 21 00:38","Sep 22 17:10","Dec 21 15:00"
"2096","Mar 19 14:03","Jun 20 06:31","Sep 21 22:55","Dec 20 20:46"
"2097","Mar 19 19:49","Jun 20 12:14","Sep 22 04:37","Dec 21 02:38"
"2098","Mar 20 01:38","Jun 20 18:01","Sep 22 10:22","Dec 21 08:19"
"2099","Mar 20 07:17","Jun 20 23:41","Sep 22 16:10","Dec 21 14:04"
"2100","Mar 20 13:04","Jun 21 05:32","Sep 22 22:00","Dec 21 19:51"
Save as seasons.csv
Now use these codes:
$Seasons=Import-Csv path\to\seasons.csv | % {
$MEqui=[DateTime]$([string]($_.Year )+$_.marequi)
$JSols=[DateTime]$([string]($_.Year )+$_.junsols)
$SEqui=[DateTime]$([string]($_.Year )+$_.sepequi)
$DSols=[DateTime]$([string]($_.Year )+$_.decsols)
[pscustomobject]#{mequi=$mequi;jsols=$jsols;sequi=$sequi;dsols=$dsols}
}
$Seasons | %{
$MEqui=$MEqui.ToString(yyyy-MM-ddTHH:mm:ssZ)
$JSols=$JSols.ToString(yyyy-MM-ddTHH:mm:ssZ)
$SEqui=$SEqui.ToString(yyyy-MM-ddTHH:mm:ssZ)
$DSols=$DSols.ToString(yyyy-MM-ddTHH:mm:ssZ)
[pscustomobject]#{MarchEquinox=$mequi;JuneSolstice=$jsols;SeptemberEquinox=$sequi;DecemberSolstice=$dsols} | Export-Csv path\to\output.csv -NoTypeInformation -Append
}
And the rest of the steps are the same (just replace $timetable1 with $seasons), this approach is better because importing from and exporting to csv is much easier and far more reliable.

Answer 1

For the template issue, it appears that you have only one sample value (Jun 21) for the junsols column, if you update that, you will see that it works just fine.
In general, I would recommend the following template to cover all the dates:
{[int]year*:0000} {[string]marequi:Mar 00 00:00} {[string]junsols:Jun 00 00:00} {[string]sepequi:Sep 00 00:00} {[string]decsols:Dec 00 00:00}
{[int]year*:9999} {[string]marequi:Mar 99 99:99} {[string]junsols:Jun 99 99:99} {[string]sepequi:Sep 99 99:99} {[string]decsols:Dec 99 99:99}
Also (as a side note): try to avoid using the increase assignment operator (+=) to create a collection as it is exponential expensive