The true calendar has to be solar as the Feast Days are directly linked to the agricultural year. The true calendar also has to have the following units of time:

1 Day = night time + day time = 24 Hours

(Gen.1:5, John 11:9)

And Elohim called the light ‘day’ and the darkness He called ‘night.’ And there came to be evening and there came to be morning, the first day. יהושע answered, “Are there not twelve hours in the day? If anyone walks in the day, he does not stumble, because he sees the light of this world.

1 Week = 7 Days

(Gen.1:1-31; Gen.2:1-3)

 In the beginning Elohim created the heavens and the earth. And the earth came to be formless and empty, and darkness was on the face of the deep. And the Spirit of Elohim was moving on the face of the waters.  And Elohim said, “Let light come to be,” and light came to be.  And Elohim saw the light, that it was good. And Elohim separated the light from the darkness. And Elohim called the light ‘day’ and the darkness He called ‘night.’ And there came to be evening and there came to be morning, the first day. And Elohim said, “Let an expanse come to be in the midst of the waters, and let it separate the waters from the waters.”  And Elohim made the expanse, and separated the waters which were under the expanse from the waters which were above the expanse. And it came to be so.  And Elohim called the expanse ‘heavens.’ And there came to be evening and there came to be morning, the second day.  And Elohim said, “Let the waters under the heavens be gathered together into one place, and let the dry land appear.” And it came to be so. And Elohim called the dry land ‘earth,’ and the collection of the waters He called ‘seas.’ And Elohim saw that it was good.  And Elohim said, “Let the earth bring forth grass, the plant that yields seed, and the fruit tree that yields fruit according to its kind, whose seed is in itself, on the earth.” And it came to be so.  And the earth brought forth grass, the plant that yields seed according to its kind, and the tree that yields fruit, whose seed is in itself according to its kind. And Elohim saw that it was good.  And there came to be evening and there came to be morning, the third day.  And Elohim said, “Let lights come to be in the expanse of the heavens to separate the day from the night, and let them be for signs and appointed times, and for days and years,  and let them be for lights in the expanse of the heavens to give light on the earth.” And it came to be so.  And Elohim made two great lights: the greater light to rule the day, and the lesser light to rule the night, and the stars.  And Elohim set them in the expanse of the heavens to give light on the earth,  and to rule over the day and over the night, and to separate the light from the darkness. And Elohim saw that it was good.  And there came to be evening and there came to be morning, the fourth day.  And Elohim said, “Let the waters teem with shoals of living creatures, and let birds fly above the earth on the face of the expanse of the heavens.”  And Elohim created great sea creatures and every living creature that moves, with which the waters teemed, according to their kind, and every winged bird according to its kind. And Elohim saw that it was good. And Elohim blessed them, saying, “Bear fruit and increase, and fill the waters in the seas, and let the birds increase on the earth.”  And there came to be evening and there came to be morning, the fifth day.  And Elohim said, “Let the earth bring forth the living creature according to its kind: livestock and creeping creatures and beasts of the earth, according to its kind.” And it came to be so.  And Elohim made the beast of the earth according to its kind, livestock according to its kind, and all that creep on the earth according to its kind. And Elohim saw that it was good.  And Elohim said, “Let Us make man in Our image, according to Our likeness, and let them rule over the fish of the sea, and over the birds of the heavens, and over the livestock, and over all the earth and over all the creeping creatures that creep on the earth.” And Elohim created the man in His image, in the image of Elohim He created him – male and female He created them.  And Elohim blessed them, and Elohim said to them, “Bear fruit and increase, and fill the earth and subdue it, and rule over the fish of the sea, and over the birds of the heavens, and over all creatures moving on the earth.” And Elohim said, “See, I have given you every plant that yields seed which is on the face of all the earth, and every tree whose fruit yields seed, to you it is for food.  “And to every beast of the earth, and to every bird of the heavens, and to every creeping creature on the earth, in which there is life, every green plant is for food.” And it came to be so. And Elohim saw all that He had made, and see, it was very good. And there came to be evening and there came to be morning, the sixth day. Thus the heavens and the earth were completed, and all their array. And on the seventh day Elohim completed His work which He had done, and He rested on the seventh day from all His work which He had made. And Elohim blessed the seventh day and set it apart, because on it He rested from all His work which Elohim in creating had made.

1 Month = 30 Days

 (Gen.7:11,24; Gen.8:3,4; Rev.11:2,3; Rev.12:6; Rev.13:5)

In the six hundredth year of Noaḥ’s life, in the second month, the seventeenth day of the month, on that day all the fountains of the great deep were broken up, and the windows of the heavens were opened. And the waters were mighty on the earth, one hundred and fifty days. And the waters receded steadily from the earth, and at the end of the hundred and fifty days the waters diminished. And in the seventh month, the seventeenth day of the month, the ark rested on the mountains of Ararat.

Rev.11:2,3

“But cast out the court which is outside the Dwelling Place, and do not measure it, for it has been given to the gentiles, and they shall trample the set-apart city under foot for forty-two months. and I shall give unto my two witnesses, and they shall prophesy one thousand two hundred and sixty days, clad in sackcloth.” And the woman fled into the wilderness, where she has a place prepared by Elohim, to be nourished there one thousand two hundred and sixty days. And he was given a mouth speaking great matters and blasphemies, and he was given authority to do so forty-two months.

1 Year = 12 Months

(I Kings 4:7;

And Shelomoh had twelve governors over all Yisra’ĕl, who provided food for the sovereign and his household – each one made provision for one month of the year –

I Chronicles 27:1-15)

And the children of Yisra’ĕl, according to their number, the heads of fathers’ houses, and the commanders of thousands and hundreds and their officers, served the sovereign in all matters of the divisions which came in and went out month by month throughout all the months of the year, each division having twenty-four thousand.

Over the first division for the first month was Yashoḇʽam son of Zaḇdi’ĕl

And over the division of the second month was Doḏai an Aḥoḥite,

for the third month was Benayahu, son of Yehoyaḏa the priest,

The fourth for the fourth month was Asah’ĕl the brother of Yo’aḇ,

The fifth for the fifth month was Shamhuth the Yizraḥite

The sixth for the sixth month was Ira son of Iqqĕsh the Teqowite,

The seventh for the seventh month was Ḥĕlets the Pelonite

The eighth for the eighth month was Sibbeḵai the Ḥushathite,

The ninth for the ninth month was Aḇiʽezer the Anathothite,

The tenth for the tenth month was Maharai the Netophathite,

The eleventh for the eleventh month was Benayah the Pirathonite,

The twelfth for the twelfth month was Ḥeldai the Netophathite,

1 Year = 12 Months x 30 Days = 360 Days

1^st Day of the Year = 5^th Day of the week

(Gen.1:14-19;)

And Elohim said, “Let lights come to be in the expanse of the heavens to separate the dayfrom the night, and let them be for signs and appointed times, and for days and years,  and let them be for lights in the expanse of the heavens to give light on the earth.” And it came to be so.  And Elohim made two great lights: the greater light to rule the day, and the lesser light to rule the night, and the stars.  And Elohim set them in the expanse of the heavens to give light on the earth,  and to rule over the day and over the night, and to separate the light from the darkness. And Elohim saw that it was good.  And there came to be evening and there came to be morning, the fourth day.

 Since the solar year is based on the sun and the sun was created or reset on the 4^th Day of the Week, it makes sense that the solar year starts with the 5^th Day of the Week after the creation or resetting of the sun was complete. Sundown on Wednesday marks the end of the 4^th Day, and begins the 5^th Day of the Week. So the Year begins at sundown on Wednesday night with the beginning of the 5^th Day of the Week.

The agricultural year is directly linked to the Feast Days and the Calendar

(Ex.23:14-17;

“Three times in the year you are to observe a festival to Me:  “Guard the Festival of

Unleavened Bread. Seven days you eat unleavened bread, as I commanded you, at

the time appointed in the month of Aḇiḇ – for in it you came out of Mitsrayim – and

do not appear before Me empty-handed;  and the Festival of the Harvest, the first-

fruits of your labours which you have sown in the field; and the Festival of the

Ingathering at the outgoing of the year, when you have gathered in the fruit of your

labours from the field.  “Three times in the year all your males are to appear before the Master יהוה.

Ex.34:21-23).

“Six days you work, but on the seventh day you rest – in ploughing time and in harvest you rest.  “And perform the Festival of Weeks for yourself, of the first-fruits of wheat harvest, and the Festival of Ingathering at the turn of the year. “Three times in the year all your men are to appear before the Master, יהוה, the Elohim of Yisra’ĕl,

1^st Month = Passover, Feast of Unleavened Bread

-beginning of the Barley Harvest with the Sheaf Offering

(Ex.12:2;

This month is the beginning of months for you, it is the first month of the year for you.

Lev.23:5-15).

‘In the first month, on the fourteenth day of the month, between the evenings, is the Passover to יהוה.  ‘And on the fifteenth day of this month is the Festival of Unleavened Bread to יהוה – seven days you eat unleavened bread.  ‘On the first day you have a set-apart gathering, you do no servile work.  ‘And you shall bring an offering made by fire to יהוה for seven days. On the seventh day is a set-apart gathering, you do no servile work.’ ”  And יהוה spoke to Mosheh, saying,  “Speak to the children of Yisra’ĕl, and you shall say to them, ‘When you come into the land which I give you, and shall reap its harvest, then you shall bring a sheaf of the first-fruits of your harvest to the priest.  ‘And he shall wave the sheaf before יהוה, for your acceptance. On the morrow after the Sabbath the priest waves it.  ‘And on that day when you wave the sheaf, you shall prepare a male lamb a year old, a perfect one, as a burnt offering to יהוה,  and its grain offering: two-tenths of an ĕphah of fine flour mixed with oil, an offering made by fire to יהוה, a sweet fragrance, and its drink offering: one-fourth of a hin of wine.  ‘And you do not eat bread or roasted grain or fresh grain until the same day that you have brought an offering to your Elohim – a law forever throughout your generations in all your dwellings.  ‘And from the morrow after the Sabbath, from the day that you brought the sheaf of the wave offering, you shall count for yourselves: seven completed Sabbaths.

3^rd Month= Feast of Weeks (Pentecost) - end of the Wheat Harvest

(Lev.23:16-22).

‘Until the morrow after the seventh Sabbath you count fifty days, then you shall bring a new grain offering to יהוה.  ‘Bring from your dwellings for a wave offering two loaves of bread, of two-tenths of an ĕphah of fine flour they are, baked with leaven, first-fruits to יהוה.  ‘And besides the bread, you shall bring seven lambs a year old, perfect ones, and one young bull and two rams. They are a burnt offering to יהוה, with their grain offering and their drink offerings, an offering made by fire for a sweet fragrance to יהוה.  ‘And you shall offer one male goat as a sin offering, and two male lambs a year old, as a peace offering.  ‘And the priest shall wave them, besides the bread of the first-fruits, as a wave offering before יהוה, besides the two lambs. They are set-apart to יהוה for the priest.  ‘And on this same day you shall proclaim a set-apart gathering for yourselves, you do no servile work on it – a law forever in all your dwellings throughout your generations.‘And when you reap the harvest of your land do not completely reap the corners of your field when you reap, and do not gather any gleaning from your harvest. Leave them for the poor and for the stranger. I am יהוה your Elohim.’ ”

7^th Month = Feast of Tabernacles –

the end of the agricultural year and the ingathering of grapes, olives, pomegranates, dates, etc.

 (Lev.23:23-44).

And יהוה spoke to Mosheh, saying, “Speak to the children of Yisra’ĕl, saying, ‘In the seventh month, on the first day of the month, you have a rest, a remembrance of blowing of trumpets, a set-apart gathering.  ‘You do no servile work, and you shall bring an offering made by fire to יהוה.’ ”  And יהוה spoke to Mosheh, saying,  “On the tenth day of this seventh month is the Day of Atonement. It shall be a set-apart gathering for you. And you shall afflict your beings, and shall bring an offering made by fire to יהוה.  “And you do no work on that same day, for it is the Day of Atonement, to make atonement for you before יהוה your Elohim.  “For any being who is not afflicted on that same day, he shall be cut off from his people. “And any being who does any work on that same day, that being I shall destroy from the midst of his people. “You do no work – a law forever throughout your generations in all your dwellings.  ‘It is a Sabbath of rest to you, and you shall afflict your beings. On the ninth day of the month at evening, from evening to evening, you observe your Sabbath.”  And יהוה spoke to Mosheh, saying,  “Speak to the children of Yisra’ĕl, saying, ‘On the fifteenth day of this seventh month is the Festival of Booths for seven days to יהוה.  ‘On the first day is a set-apart gathering, you do no servile work.  ‘For seven days you bring an offering made by fire to יהוה. On the eighth day there shall be a set-apart gathering for you, and you shall bring an offering made by fire to יהוה. It is a closing festival, you do no servile work. ‘These are the appointed times of יהוה which you proclaim as set-apart gatherings, to bring an offering made by fire to יהוה, a burnt offering and a grain offering, a slaughtering and drink offerings, as commanded for every day –  besides the Sabbaths of יהוה, and besides your gifts, and besides all your vows, and besides all your voluntary offerings which you give to יהוה.  ‘On the fifteenth day of the seventh month, when you gather in the fruit of the land, observe the festival of יהוה for seven days. On the first day is a rest, and on the eighth day a rest.  ‘And you shall take for yourselves on the first day the fruit of good trees, branches of palm trees, twigs of leafy trees, and willows of the stream, and shall rejoice before יהוה your Elohim for seven days.  ‘And you shall observe it as a festival to יהוה for seven days in the year – a law forever in your generations. Observe it in the seventh month.  ‘Dwell in booths for seven days; all who are native Yisra’ĕlites dwell in booths,  so that your generations know that I made the children of Yisra’ĕl dwell in booths when I brought them out of the land of Mitsrayim. I am יהוה your Elohim.’ ” Thus did Mosheh speak of the appointed times of יהוה to the children of Yisra’ĕl.

Now that we know what units of time the true calendar consists of, we can now look for a calendar that meets these criteria.

The True Calendar of the Bible

The only Calendar that meets all of these criteria is the Solar Calendar found at Qumran mentioned in Mismarot from Cave IV, also mentioned in the Book of Enoch (I Enoch)

Chap.72-75,

After this law I beheld another law of an inferior luminary, the name of which is the moon, and the orb of which is as the orb of heaven.Its chariot, which it secretly ascends, the wind blows; and light is given to it by measure Every month at its exit and entrance it becomes changed; and its periods are as the periods of the sun. And when in like manner its light is to exist, ⁽⁷⁹⁾ its light is a seventh portion from the light of the sun.

(79) And when in…is to exist. I.e., when the moon is full (Knibb, p. 171).

Thus it rises, and at its commencement towards the east goes forth for thirty days.At that time it appears, and becomes to you the beginning of the month. Thirty days it is with the sun in the gate from which the sun goes forth.Half of it is in extent seven portions, one half; and the whole of its orb is void of light, except a seventh portion out of the fourteen portions of its light. And in a day it receives a seventh portion, or half that portion, of its light. Its light is by sevens, by one portion, and by the half of a portion. Its sets with the sun. And when the sun rises, the moon rises with it; receiving half a portion of light.On that night, when it commences its period, previously to the day of the month, the moon sets with the sun.And on that night it is dark in its fourteen portions, that is, in each half; but it rises on that day with one seventh portion precisely, and in its progress declines from the rising of the sun.During the remainder of its period its light increases to fourteen portions.

Chapter 73

Then I saw another progress and regulation which He effected in the law of the moon. The progress of the moons, and everything relating to them, Uriel showed me, the holy angel who conducted them all.Their stations I wrote down as he showed them to me.I wrote down their months, as they occur, and the appearance of their light, until it is completed in fifteen days.In each of its two seven portions it completes all its light at rising and at setting.On stated months it changes its settings; and on stated months it makes its progress through each gate. In two gates the moon sets with the sun, viz. in those two gates which are in the midst, in the third and fourth gate. From the third gate it goes forth for seven days, and makes its circuit.Again it returns to the gate whence the sun goes forth, and in that completes the whole of its light. Then it declines from the sun, and enters in eight days into the sixth gate, and returns in seven days to the third gate, from which the sun goes forth.When the sun proceeds to the fourth gate, the moon goes forth for seven days, until it passes from the fifth gate.Again it returns in seven days to the fourth gate, and completing all its light, declines, and passes on by the first gate in eight days;And returns in seven days to the fourth gate, from which the sun goes forth.Thus I beheld their stations, as according to the fixed order of the months the sun rises and sets.At those times there is an excess of thirty days belonging to the sun in five years; all the days belonging to each year of the five years, when completed, amount to three hundred and sixty-four days; and to the sun and stars belong six days; six days in each of the five years; thus thirty days belonging to them;So that the moon has thirty days less than the sun and stars.The moon brings on all the years exactly, that their stations may come neither too forwards nor too backwards a single day; but that the years may be changed with correct precision in three hundred and sixty-four days. In three years the days are one thousand and ninety-two; in five years they are one thousand eight hundred and twenty; and in eight years two thousand nine hundred and twelve days.To the moon alone belong in three years one thousand and sixty-two days; in five years it has fifty days less than the sun, for an addition being made to the one thousand and sixty-two days, in five years there are one thousand seven hundred and seventy days; and the days of the moon in eight years are two thousand eight hundred and thirty-two days.For its days in eight years are less than those of the sun by eighty days, which eighty days are its diminution in eight years.The year then becomes truly complete according to the station of the moon, and the station of the sun; which rise in the different gates; which rise and set in them for thirty days.

Chapter 74

 These are the leaders of the chiefs of the thousands, those which preside over all creation, and over all the stars; with the four days which are added and never separated from the place allotted them, according to the complete calculation of the year.And these serve four days, which are not calculated in the calculation of the year.Respecting them, men greatly err, for these luminaries truly serve, in the dwelling place of the world, one day in the first gate, one in the third gate, one in the fourth gate, and one in the sixth gate.And the harmony of the world becomes complete every three hundred and sixty-fourth state of it. For the signs,The seasons,The years,And the days, Uriel showed me; the angel whom the Lord of glory appointed over all the luminaries.Of heaven in heaven, and in the world; that they might rule in the face of the sky, and appearing over the earth, becomeConductors of the days and nights: the sun, the moon, the stars, and all the ministers of heaven, which make their circuit with all the chariots of heaven.Thus Uriel showed me twelve gates open for the circuit of the chariots of the sun in heaven, from which the rays of the sun shoot forth.From these proceed heat over the earth, when they are opened in their stated seasons. They are for the winds, and the spirit of the dew, when in their seasons they are opened; opened in heaven at its extremities.Twelve gates I beheld in heaven, at the extremities of the earth, through which the sun, moon, and stars, and all the works of heaven, proceed at their rising and setting.Many windows also are open on the right and on the left.One window at a certain season grows extremely hot. So also are there gates from which the stars go forth as they are commanded, and in which they set according to their number.I saw likewise the chariots of heaven, running in the world above to those gates in which the stars turn, which never set. One of these is greater than all, which goes round the whole world.

Chapter 75

And at the extremities of the earth I beheld twelve gates open for all the winds, from which they proceed and blow over the earth.Three of them are open in the front of heaven, three in the west, three on the right side of heaven, and three on the left. The first three are those which are towards the east, three are towards the north, three behind those which are upon the left, towards the south, and three on the west.From four of them proceed winds of blessing, and of health; and from eight proceed winds of punishment; when they are sent to destroy the earth, and the heaven above it, all its inhabitants, and all which are in the waters, or on dry land.The first of these winds proceeds from the gate termed the eastern, through the first gate on the east, which inclines southwards. From this goes forth destruction, drought, heat, and perdition.From the second gate, the middle one, proceeds equity. There issue from it rain, fruitfulness, health, and dew; and from the third gate northwards, proceed cold and drought.After these proceed the south winds through three principal gates; through their first gate, which inclines eastwards, proceeds a hot wind.But from the middle gate proceed grateful odour, dew, rain, health, and life.From the third gate, which is westwards, proceed dew, rain, blight, and destruction.After these are the winds to the north, which is called the sea. They proceed from three gates. The first ⁽⁸⁰⁾ gate is that which is on the east, inclining southwards; from this proceed dew, rain, blight, and destruction. From the middle direct gate proceed rain, dew, life, and health. And from the third gate, which is westwards, inclining towards the south, proceed mist, frost, snow, rain, dew, and blight.

(80) First. Or, "seventh" (Knibb, p. 178).

After these in the fourth quarter are the winds to the west. From the first gate, inclining northwards, proceed dew, rain, frost, cold, snow, and chill; from the middle gate proceed rain, health, and blessing;And from the last gate, which is southwards, proceed drought, destruction, scorching, and perdition.The account of the twelve gates of the four quarters of heaven is ended.All their laws, all their infliction of punishment, and the health produced by them, have I explained to you, my son Mathusala. ⁽⁸¹⁾

81) Mathusala. Enoch's son, Methuselah. Cp. Gen. 5:21.

          as well as in the

Book of Jubilees

Chap.6:23-38,

 And on the new moon of the first month, and on the new moon of the fourth month, and on the new moon of the seventh month, and on the new moon of the tenth month are the days of remembrance, and the days of the seasons in the four divisions of the year. These are written and ordained  as a testimony for ever. And Noah ordained them for himself as feasts for the generations for ever,  so that they have become thereby a memorial unto him. And on the new moon of the first month he was bidden to make for himself an ark, and on that (day) the earth became dry and he opened (the ark) and saw the earth. And on the new moon of the fourth month the mouths of the depths of the abyss beneath were closed. And on the new moon of the seventh month all the mouths of  the abysses of the earth were opened, and the waters began to descend into them. And on the new  moon of the tenth month the tops of the mountains were seen, and Noah was glad. And on this account he ordained them for himself as feasts for a memorial for ever, and thus are they ordained.

and has the following characteristics:

This calendar has 1 Week = 7 Days, 1 Month = 30 Days, 1 Year = 12 Months, 1 Year= 360 Days plus 4 intercalary days to make an even 364 Day Year which is perfectly divisible by the 7 day week to give 52 Weeks a year, 1^st Day of the Year = 5^th Day of the Week; 1^st Month = start of the Barley Harvest.

This is a fixed Calendar with the 1^st Day of the Year and the 1^st Day of each 3 month period falling on Wednesday night the beginning of the 5^th Day of the Week. The dates of the feasts are also fixed with a particular day of any given month being on the same day of the week every year. One intercalary day is fixed at the end of each 3 month period and acts as a buffer or division point between the next season or 3 month period. Each season or 3 month period has exactly 13 weeks. Here is what the reconstructed calendar looks like (keeping in mind that as Sabbath is on Saturday but starts Friday night so all the days in this calendar start the night before):

The 1st, 4th, 7th, and 10th Months