What Changed in My Chart This Month

Someone typed this into our chart chat: "Mercury is transiting into 8th house (Leo) as per chart next week. What changes will that be bringing?"

The question is asking for a diff: a comparison between how the chart stood a month ago and how it stands now, with the differences named. A scan of what the large Indian astrology sites publish on a recurring schedule found every one of those surfaces keyed to sun sign, one page per twelfth of the population, which is the one thing a diff cannot be. A diff has to be computed against one person's own chart.

Most of what follows can be read without giving anyone your birth details, and the last part of the page measures precisely what the rest of it needs them for.

The month worked through below is September 2026, compared against August 2026. Every sky figure and every date on this page is recomputed when the month turns, and the parts that do not turn over, which are the aspect arithmetic, the population statistics and the birth-time sensitivity, stay as they are.

The chart itself does not change, so name what does

Your birth chart is a photograph. Every planet in it holds the degree it held at your first breath, for life, and nothing that happens in September moves any of them. So the honest reading of "what changed in my chart" is: what changed in the relationship between that fixed photograph and the moving sky, and what changed in the clock this tradition runs a life by.

Three things can move, and nothing else can.

One, where each transiting planet sits relative to your chart. A transiting planet is simply where that planet is in the sky today. It counts as having moved for your purposes when it crosses out of one sign into the next, because the house it occupies in your chart is decided by its sign, not by its degree.

Two, which planetary period is running. A dasha is a planetary period, meaning a stretch of your life the tradition assigns to one planet and dates from end to end. Vimshottari, the 120-year cycle those periods run in, advances on dates unique to you, decided by where the Moon stood at the minute of your birth.

Three, whether a transiting planet arrived at the exact degree of one of your own planets. A transiting planet spends weeks or months in a sign. Somewhere inside that stay there may be a single dated day when its own longitude lands on the longitude your natal planet occupies, and that day is the finest resolution this method produces.

Every monthly page that has ever been written is one of those three restated, usually the first one and usually without dates. The rest of this page does all three, for September 2026, with the dates.

Layer one: what actually moved in the sky in September 2026

Below are the sidereal positions of all nine bodies on 1 and 30 September 2026, and the ground each one covered in between. Sidereal here means measured against the fixed stars, which is the frame Vedic astrology has always used and the frame every number on this page is in.

Retrograde means the planet is moving backwards through the zodiac as seen from Earth. Saturn, Rahu and Ketu are all doing that through September. For Rahu and Ketu, which are the two points where the Moon's path crosses the Sun's, backward motion is their permanent condition rather than a phase, so it is not news about September. For Saturn it is a phase, and it is the reason Saturn ends the month two degrees behind where it started.

The whole of layer one for the month reduces to five dated moments, each timed here to the minute in Indian Standard Time.

Four bodies out of the eight that matter for a monthly diff do not change sign at all.

Saturn covering two degrees in a month is the single most useful fact on this page for anyone who has been reading monthly horoscopes and wondering why they all sound the same. The slow planets are the ones every reading leans on for weight, and in a calendar month they barely move. Saturn stood at Pisces 20.49 on 1 August and at Pisces 17.38 on 30 September, which is three degrees of movement across two entire months, all of it backwards over ground it had already covered. A page that reports a dramatic Saturn development every month is reporting something that did not happen.

The Moon, and why it is left out of the diff

The Moon changes sign 13 times in September 2026 and changes nakshatra 28 times. A nakshatra is one of the 27 segments of 13 degrees 20 minutes each that the zodiac divides into, and the Moon crosses roughly one a day.

The Moon is therefore not a monthly quantity at all. It touches every house of your chart, aspects every planet in it, and returns to where it started, all inside the month. Putting it in a monthly diff would fill the diff with facts that were equally true last month and will be equally true next month. The Moon belongs in a daily reading, where it is the whole story, and it is left out of everything below.

The bodies that do move at a monthly rate change nakshatra eight times between them.

One thing that does not happen in September, and its date

No planet reverses direction inside the month. Venus comes close. Its daily speed falls from 0.79 degrees on 1 September to 0.11 degrees on 30 September, and a planet moving at under 15% of its own average speed is classed as stationary here, which is why the first table gives Venus that label on the 30th rather than direct. Venus reverses on 3 October 2026 at Libra 14.26 and Mercury follows on 24 October 2026 at Libra 26.75.

The absence matters more than it sounds, because a reversal is the highest-signal event a planet produces all year and September 2026 is the last clear month before two of them.

Layer one, turned into your houses

A house is a twelfth of your chart, and in the Whole-Sign method this engine uses, each sign is exactly one house. Your first house is the whole sign that was rising on the eastern horizon at the minute and place you were born, called the lagna. The next sign along is your second house, and so on round.

That arithmetic gives a useful shortcut. Counting houses from your lagna sign and counting them from your Moon sign are the same operation with a different starting point, so one table serves both readings. Find your rising sign in the left column for the reading from the lagna, or find your Moon sign in the same column for the reading from the Moon, which is what a chart without a reliable birth time falls back on.

And here is the full picture at each end of the month, so you can see what stands where rather than only what moved.

Houses on 1 September 2026

Houses on 30 September 2026

Read the two grids against each other and layer one turns out to be identical in size for everybody. Whatever your rising sign, four of your eight planets change house during September, Mercury changes twice, and your chart passes through 13 separate spans of house occupancy across the month rather than eight. The house numbers differ from sign to sign. The amount of movement does not, and it cannot, because a sign change is a fact about the sky and the sky is the same sky for all of us.

That is worth saying plainly, because it is the ceiling on what any page written for your sign can ever tell you. Everything above is real, it is dated, and it is the same for every one of the roughly one in twelve people who share your rising sign. Layers two and three are where charts stop agreeing with each other.

You can get your own rising sign, Moon sign and full natal chart free at the kundli tool, which gives you the left-hand column for every table above.

Layer two: the period ladder, and how rarely it actually moves

Vimshottari divides your life into nine major periods called mahadashas, each ruled by one planet and each of a fixed length: Ketu 7 years, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, Mercury 17. Inside each mahadasha runs an antardasha, a sub-period ruled by each of the nine planets in turn in the same order. Inside each antardasha runs a pratyantar, a sub-period one level smaller again. The third level is the only one that changes on a timescale a monthly reader can feel, since a pratyantar runs weeks to months while a mahadasha runs years.

The whole ladder is anchored by one number: the exact longitude of the Moon at your birth. That fixes your birth nakshatra and how far through it the Moon had already travelled, which decides how much of your first mahadasha had already elapsed when you were born. Every boundary date in the ladder, for the rest of your life, counts from that single figure. You can see your own ladder free at the dasha tool, and the mechanics are set out at greater length in what Vimshottari dasha actually is.

Now the part almost nobody publishes, which is how often any of it moves inside one month.

We cast 8,766 charts, one every three days from 1 January 1994 to 31 December 2005 at six clock times a day, for New Delhi, and read each one's full three-level ladder across September 2026.

For more than half of all charts, the correct answer to "did my period change this month" is no. That is the single most useful thing this section contains, and it is the opposite of what a monthly horoscope implies by publishing something new every four weeks. Nineteen charts in twenty, 95.08% of the sample, see either nothing or exactly one handover. A mahadasha, which is the chapter change people usually mean when they ask about their dasha, arrives for about one chart in 161 in any given month, because a mahadasha lasts between six and twenty years and there are only nine of them in a lifetime.

Absence here is information rather than a null result. Knowing that the period running under your September is the same one that ran under your August, and will still be running in October, tells you that whatever you are in the middle of has not been reset and that the sensible move is to keep going rather than to wait for a change that is not coming.

Over a longer horizon the handovers do add up. Across a sweep of 2,192 charts through all 24 months from September 2026 to August 2028:

So a typical chart gets a period handover in about nine months out of any twenty-four, and gets none in the other fifteen. A monthly reading therefore has to be honest about the months where the answer is that nothing turned over, and "nothing changed at this level" has to be a printable result rather than a gap the writing papers over.

Layer three: the day a transit lands on your own degree

Here is where a chart stops resembling any other chart, and it is the layer that no page written for a sign can carry at all.

In this system a planet aspects, meaning it casts its influence on, the seventh sign from itself, counting inclusively so that the seventh sign from Aries is Libra. Beyond that, Mars also aspects the 4th and the 8th sign from itself, Jupiter the 5th and the 9th, and Saturn the 3rd and the 10th. Rahu and Ketu are read here as aspecting the 5th, 7th and 9th. Jupiter has no 11th aspect, however often that gets written down.

Counted in degrees rather than in signs, the nth aspect lands on the point (n minus 1) times 30 degrees ahead of the planet. A planet's seventh aspect is therefore the point directly opposite it, 180 degrees on, and Saturn's tenth aspect is the point 270 degrees ahead of Saturn.

The sign version of that claim is true for as long as the planet stays in the sign, which for Saturn is about two and a half years. The degree version is true on one dated day. When transit Saturn's own longitude reaches the exact longitude your natal Jupiter occupies, the aspect the sign table has been describing loosely for months lands precisely, and that is a date a monthly diff can hand you.

What September 2026 activates, so you can check your own chart

Each transiting body sweeps a definite arc of sidereal longitude across the month. Its conjunction lands on natal points inside that arc, and each of its aspects lands on natal points inside the same arc shifted forward by the aspect's offset. Take your own planetary degrees from the kundli tool and read down this table. Anything of yours that falls inside one of these bands receives an exact contact in September 2026.

Two mechanical points before anyone over-counts. Rahu and Ketu sit exactly 180 degrees apart by construction, so Rahu's conjunction band and Ketu's seventh-aspect band are the same band, and the two contacts always fall on the same instant. They are one event reported twice, not two events. And the narrowness of the Saturn and node bands is the same fact as the earlier table: a body that covers two degrees in a month can only reach natal points inside a two-degree window, so Saturn contacts are rare and correspondingly worth dating.

How much of the zodiac one month reaches

Add every band in the table above together, at a resolution of one thousandth of a degree, and 53.25% of the zodiac receives at least one exact contact in the 30 days from 1 September 2026. Restricting to the five slower bodies, Mars, Jupiter, Saturn, Rahu and Ketu, it is 28.39%.

So a natal point dropped at random has slightly better than even odds of being touched in a given month. Across nine planets that predicts 4.79 of them touched. Measuring it directly on the 8,766-chart sample returns a mean of 4.92 and a median of 5, and the small excess over the prediction is because natal positions are not scattered at random. Mercury and Venus are never far from the Sun, so charts carry clusters rather than nine independent points.

And the contacts are not evenly shared out between the transiting bodies.

Mercury alone produces 21,947 exact contacts against 10,139 for Jupiter, Saturn, Rahu and Ketu put together, for the plain reason that it covered 46 degrees in September while Saturn covered two. That is the honest counterweight to the whole exercise: counting contacts rewards fast planets, and a fast planet's contact lasts hours. A Saturn contact is worth more than a Mercury contact and it is one eleventh as common, so a month's diff should be sorted by weight rather than by count.

One inflation to know about before using any of these counts. Natal Rahu and natal Ketu are always 180 degrees apart, so a transiting body conjunct one of them opposes the other at the same instant and the count records two. The pair is a single event, and chart one below carries two of them inside September.

Which contacts happen once, and which happen three times

A slow planet reverses direction once or twice a year, and while it is reversed it re-crosses ground it has already covered. Any natal degree caught inside that stretch of doubled-back sky receives the same contact three times rather than once: on the way through, on the way back, and on the way through again.

Those stretches are known in advance, because the reversal points are computable. Here they are for the current cycle.

A contact inside one of those bands is a season rather than a day, and it usually reads as an issue that surfaces, gets set aside, and comes back. A contact outside them is a single date and is done. The boundary between the two is a fraction of a degree wide, and the second worked chart below sits within half a degree of one of them, which is what that band edge looks like in practice.

Two charts, the same month, two completely different diffs

Both charts below are computed the same way and shown in full. Neither is a summary of the other.

Chart one: 26 July 1997, 12:17, Kolkata

Libra rising at 16.37 degrees, Moon in Aries. Debilitated means the planet is in the sign where this system reads it as weakest, which for Jupiter is Capricorn.

Layer two moves, and it moves at both of the levels that matter. This chart is in a Sun mahadasha that runs 15 November 2022 to 14 November 2028. Inside it, a Saturn antardasha that began on 21 September 2025 ends on 3 September 2026, and a Mercury antardasha begins the same day. The pratyantar hands over on the same date, from Jupiter to Mercury.

The shared date needs explaining, because it is structural rather than a coincidence. The sub-periods inside any period always run in the standard order starting from the period's own lord, so the first pratyantar inside a Mercury antardasha is always the Mercury pratyantar. Two levels of the ladder therefore always turn over on the same instant, and a chart that gets an antardasha handover gets a pratyantar handover free with it.

An antardasha handover puts this chart in the 5.81% of the sample, and the honest framing is that the September diff for this person is dominated by one date. Everything else in this chart's month is detail hung around 3 September.

Layer one. Four planets change house, as they do for everyone.

Mercury deserves a note, since it is the planet whose period just started. It passes through three houses in the month, 11th until 7 September, 12th until 26 September, and the 1st from then on, so it ends the month inside the rising sign, still 10.6 degrees short of the rising degree itself. Reading the antardasha handover and Mercury's arrival on the lagna as one thing rather than two is the sort of join a monthly page is for.

Saturn holding the 12th house from the Aries Moon for the whole month is the other standing fact. Saturn crossing the sign before your Moon, your Moon's own sign and the sign after it is called Sade Sati, a stretch of roughly seven and a half years, and Pisces is the first of those three signs for an Aries Moon. It began before September and it does not end inside it. You can check your own position in that cycle at the Sade Sati tool.

Layer three: eleven exact contacts, three of them from slow bodies.

Two pairs of rows in that table are single events. Natal Rahu at Leo 28.31 and natal Ketu at Aquarius 28.31 are 180 degrees apart, so transit Mercury on the 6th and the transit Sun on the 15th each reach both at the identical instant. Eleven rows are therefore nine separate moments, which is worth deducting before comparing this chart with any other.

The two Mars contacts four hours apart on 10 September are also a product of the natal chart's own geometry, in a different way. Natal Mars sits at Virgo 24.90 and natal Jupiter at Capricorn 24.99, the same degree of two different signs, and Mars reaches the fourth-aspect point of one and the eighth-aspect point of the other from positions 0.09 degrees apart. Pairs like that recur together every time, for life.

Transit Mars reaching Gemini 24.90, which is the point it has to occupy to aspect natal Mars, is a single event rather than a season. It makes this pass on 10 September 2026 and makes no other between June 2025 and June 2028, because Mars needs about two years to come round again and its next reversal, in January 2027, happens in Leo, far past the relevant degree.

Transit Jupiter opposing natal Jupiter on 29 September is the opposite case, and it is the strongest contact of the month for this chart. Transit Jupiter is in Cancer, its exaltation sign, meaning the sign this system reads it as strongest in. Natal Jupiter is in Capricorn, debilitated. The target point, Cancer 24.99, sits inside the doubled band from the table above, so the contact repeats: 29 September 2026, then 5 March 2027, then 22 May 2027.

And the comparison with last month, which is the actual question. August 2026 delivered this chart eleven exact contacts as well, but only two from slow bodies, and both landed on the same instant on 29 August: transit Ketu conjunct natal Mercury at Leo 5.21, with transit Rahu opposing the same point. So the diff between August and September for this person is not the count. It is that August's slow contact was a node arriving on the natal Mercury, September's are Mars and Jupiter, and the period ladder turned over in between.

One thing to hold for later rather than for this month: transit Saturn reaches natal Saturn at Pisces 26.50 on 2 May 2027. A planet returning to its own birth position is the longest cycle a chart carries, and Saturn's takes about 29 and a half years.

Chart two: 6 April 1999, 16:30, Guwahati

Virgo rising at 7.08 degrees, Moon in Scorpio. Own sign means the planet sits in a sign it rules, which for Jupiter includes Pisces.

Layer two does not move at all, and it did not move last month either. A Venus mahadasha runs 22 April 2015 to 22 April 2035. A Jupiter antardasha runs 22 June 2025 to 21 February 2028. A Ketu pratyantar began on 18 August 2026 and runs to 14 October 2026, 57 days, so it opened in the middle of last month and closes in the middle of next. Nothing in the ladder crosses a boundary in September, which puts this chart in the 56.39% majority.

That is a real answer rather than an empty one. The correct thing to tell this person is that the sub-period that started three weeks ago is still bedding in, that the chapter it sits inside has another seventeen months to run, and that any change they notice in September comes from the other two layers rather than from a shift in the period.

Layer one.

The Sun crossing into Virgo on 17 September puts it in this chart's own rising sign for the rest of the month. The Sun and Mercury both leave the 12th house and cross onto the ascendant, and Venus, already sitting there on the 1st, moves on into the 2nd. Three of the four movers therefore end the month on or past the ascendant, which is the plainest shape layer one produces for a Virgo rising in this particular month.

Layer three: eleven exact contacts, four of them from slow bodies, and they cluster.

Three slow contacts inside four days, 15 to 18 September, and each one behaves differently over the longer cycle. The differences between them are the whole argument for computing a diff rather than describing one.

Saturn arriving on natal Jupiter, 16 September. Natal Jupiter here is in its own sign in the 7th house, and Saturn crossing it is the heaviest single event either chart on this page receives. It falls inside Saturn's doubled band, so it is the middle of three passes: 7 June 2026, 16 September 2026, 26 February 2027. The June pass has already happened. The February one closes it. September is the return leg, which in practice is the pass where whatever surfaced in June comes back needing a decision rather than a first look.

Jupiter's ninth aspect reaching natal Sun, 15 September. Jupiter has to be at Cancer 22.36 to make that contact. Jupiter turns backward in December and returns to forward motion on 13 April 2027 at Cancer 22.75, which is 0.39 degrees short of the target. So Jupiter never re-crosses it. This contact happens once and does not come back. The band edge is not an abstraction. The miss here is 23 arcminutes, and 23 arcminutes is the difference between a date and a season.

Jupiter's fifth aspect reaching natal Moon, 18 September. Same planet, same month, opposite answer. The target is Cancer 22.90, which is on the far side of that same turning point by 0.15 degrees, so Jupiter does re-cross it: 18 September 2026, then 3 April 2027, then 23 April 2027, the last two only twenty days apart because Jupiter is nearly stopped there. Two contacts from one planet in one week, and one of them is finished while the other has two of its three passes still ahead.

Against last month. August 2026 gave this chart nine exact contacts with two from slow bodies: Mars aspecting the lagna on 13 August, and Jupiter's ninth aspect reaching natal Jupiter on 27 August. So the month-over-month change is that a scattered August became a clustered September, with three slow contacts landing inside four days on the 7th house, the Sun and the Moon.

And the same forward note as the other chart: transit Saturn reaches natal Sun at Pisces 22.36 on 30 March 2027. A single pass, because Pisces 22.36 sits above the upper edge of Saturn's doubled band at Pisces 20.52, so Saturn arrives there only once it is moving forward again and does not come back.

What the two charts show when you put them side by side

Same month, same sky, same five ingresses, same 13 spans of house occupancy. Then:

Layer one was identical for both. Layers two and three agreed on nothing. Which is the answer to why a monthly page keyed to a sign cannot do this: the part it can tell you is the part that is the same for everyone, and the part that separates two people is exactly the part it does not have the inputs for.

What this needs your birth data for, measured

Two of the three layers are keyed to the minute of birth, and the size of that dependence is measurable rather than a matter of assertion. We cast 4,000 charts with random dates from 1985 to 2005 and random clock times, then cast each one again at 10, 30 and 60 minutes later.

Ten minutes of error slides the entire ladder by about five and a half weeks, because the fraction of your birth nakshatra the Moon had already crossed sets the start of the whole 120-year sequence and a small fraction of 13 degrees 20 minutes is a large number of years downstream. A monthly diff built on the wrong minute reports handovers that are not yours.

Layer one is more forgiving, and it is worth knowing by how much.

A rising sign lasts roughly two hours, so a ten-minute error costs you the house layer about one time in twelve. So if your birth time is approximate, the honest thing to do is to read the house tables from your Moon sign instead, since the Moon changes sign only every two and a bit days and a birth time that is an hour out almost never moves it. That reading is a real one and the tradition uses it constantly. It is also the reading everything on this page falls back to when the birth time is a placeholder rather than a record.

Layer three needs neither the birth time nor the rising sign, only your planetary degrees, which are fixed by the date and are stable to a fraction of a degree across a whole day for everything except the Moon. So the band table above is usable by anyone who knows their date of birth, and it is the part of this page a reader with no birth certificate can still act on.

Getting your own version, and what is actually behind the gate

Everything above is the September 2026 sky and the population statistics, and all of it is free and checkable, with every date on it. What it cannot do is the join. Your rising sign turns the ingress table into your houses, your Moon's longitude turns the calendar into your handover dates, and your natal degrees turn the band table into a list with your planets in it.

Create an account and the diff is computed for you and recomputed each month, which is the part that matters: the value of a diff is that it arrives without you having to remember to ask. What you get is the three layers already joined, meaning your own dated house transitions, your period handovers for the month or a plain statement that there are none, and every exact contact with which of the three passes it is. If you want to interrogate any of it in your own words, chart chat reads the same computed facts, and the question at the top of this page is one it answers directly.

If you would rather not create an account, the Month-Ahead Report covers the next 30 days from the moment you buy it, adds the per-day strong and guarded dates read against your own birth star, and arrives by email without a sign-up.

How to read a diff without over-reading it

Four cautions, each of which this page's own numbers support.

A house change is not an event. A planet entering your 6th house has entered it, and that is all the statement contains. It fires for one person in twelve on the same day, so anything specific enough to be worth acting on is not coming from that fact alone.

Absence is the common case and the correct answer. More than half of all charts have no period handover in a given month, and 7.54% receive no slow-body contact. A month in which the honest report is that nothing at the deeper layers moved is the most likely single outcome, and a page that manufactures something is telling you about its publishing schedule rather than your chart.

Weight beats count. Mercury generates 32.62% of all exact contacts in the sample and Saturn 2.89%, purely because of speed. A month with nine Mercury contacts and no Saturn is a quieter month than one with a single Saturn contact.

A contact is a date, not a verdict. Nothing on this page predicts an outcome, and the two worked charts are deliberately shown with their contacts described by geometry rather than by consequence. The useful output of a monthly diff is knowing which dates carry weight for you and which do not, so that when something does happen you can see what it landed on.

Method

Every position on this page comes from the Swiss Ephemeris, running the Moshier theory, in the sidereal frame with the Lahiri ayanamsa, using the mean lunar node, read through the AstroMedha engine at commit 77b4825. Houses are Whole-Sign throughout. The aspect offsets are read from the same aspect table the chart reader uses, so a claim here and a claim there cannot disagree.

Ingress and contact instants are found by scanning the longitude at six-hour or twelve-hour steps for a change of algebraic sign in the difference from the target, then bisecting to the minute, and are printed in Indian Standard Time. Reversal dates come from the change of algebraic sign in the daily speed, and the degree at each reversal is taken as the actual extreme of longitude reached, sampled every three hours across a fifty-day bracket. A reversal date carries wider uncertainty than an ingress, on the order of hours, because the speed near a reversal is close to zero. The degree does not, for exactly the same reason: a body that is barely moving does not move far while the date is in doubt, which is why the band edges above are quoted to two decimals and relied on to that precision.

The population figures come from 8,766 charts cast every three days from 1994 to 2005 at six clock times a day for New Delhi, the 24-month sweep from every fourth chart of that set, and the birth-time sensitivity from a separate 4,000-chart random sample. The contact counts are measured over the 30 days from 12:00 on 1 September 2026, which is the sampling window rather than the calendar month, and the difference between the two definitions is under a day at either end.

Nothing here is a forecast, and no claim on this page is anything other than where a body was, where it will be, and on what date the two lines cross.

Related

• Free kundli, your full natal chart with every degree
• Free dasha calculator, your period ladder from birth
• What Vimshottari dasha actually is
• Sade Sati calculator
• Your nakshatra and what it carries
• Why your Moon sign differs here
• When will I get a job, your next 24 months month by month
• All Vedic insights