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Tropical vs Vedic Sidereal vs True Sidereal Astrology

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PRE-ARTICLE BTW (March 30, 2021), I interviewed Richard Mason, creator of Cosmic Human Design. Check out the post right here.

UPDATE December 21, 2021 ➡️ Here’s an update on my own human design experiment!



(Psst…MOST of my comments below about the differences in my chart are from the perspective of “Do I see myself in my chart? Human design is actually about EXPERIMENTING. It’s not about whether you see yourself in your chart or not – validating your chart can only be done through experimentation. SO, keep that in mind when reading my comments 😆.)

So…I’m not an astrologer, I’m just sharing what I’m learning as I’m learning it.

I first heard about sidereal (vedic) astrology through Fani Purdy (formerly @newparadigmbizbestie but now @mamacapricorn) who started sharing her perspective on discussions happening in the human design community. I’m not “in” the HD community, so this was all new to me.

Tiffani has shared her thoughts on HD being treated as dogma, or an infallible belief system (it’s not), as well as about the “founder,” Ra Uru Hu (Robert Krakower).

I’m not going to get into all that, because it’s a conversation I’m not really part of, nor do I know much about it; however, reading Fani’s recent posts and listening to one of her IGTVs got me very curious about the whole tropical vs sidereal astrology situation (**I had links to these posts and videos, but Fani has since removed them).

Apparently (again, not an astrologer), tropical astrology is not very accurate in terms of the actual placements of the stars and planets.

As per a very informative Wiki article:

Sidereal astrology uses corrective systems known as ayanamsas (Sanskrit: ‘ayana’ “movement” + ‘aṃśa’ “component”) to account for the precession of equinoxes, whereas tropical astrology does not use such measures. This has caused the two systems, which were identical around 2,000 years ago, to drift apart over the centuries.Wikipedia + various cited sources within said Wikipedia article

SO, 2000 years of drifting apart could result in some major differences in how a human design chart is calculated, no?

I was extremely curious, so I upgraded my Genetic Matrix* account to pro just so I could calculate my HD chart using sidereal astrology (*affiliate link). (April 9, 2021 Correction: I actually had a plus account, and it was apparently an error that allowed me to calculate sidereal charts. A “pro” membership is required to calculate any type of chart other than tropical).

Some people’s charts are completely different. For example, Tiffani Purdy shared on her IG account that tropical astrology said she was a manifesting generator, but with sidereal, she’s a projector. Those are two extremely different things.

BIG LESSON: No chart can define you. Trust yourself, your body, and your intuition.

Since diving down this rabbit hole, I’ve learned that vedic sidereal astrology and how it’s used to calculate human design charts is different from what’s being called “true sidereal” astrology, which is meant to be more accurate based on where everything actually was at the time and place of your birth. See Richard Mason (“Cosmic Human Design”) for more information on this.

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Below are three charts – all mine – according to the three types of astrology. First, tropical, which is the chart I’ve been working with for over a year. (Find my thoughts on the differences at the end.)

My Human Design Chart: Tropical vs Vedic Sidereal vs True Sidereal Astrology


Tropical Astro HD Chart Vedic Sidereal Astro HD Chart True Sidereal / Cosmic HD Chart
Type Splenic Projector Splenic Projector Sacral Manifesting Generator
Profile 4/6 – Opportunist / Role Model 2/4 – Hermit / Opportunist 6/3 – Role Model / Martyr
Definition Single Single Split
Incarnation Cross RAX Rulership 4 RAX Contagion 4 LAX Defiance 2
Channels 26-44 Surrender
28-38 Struggle
18-58 Judgement 2-14 The Beat
10-34 Awakening/Exploration
16-48 The Wavelength
29-46 Discover/Succeeding where others fail
32-54 Transformation
Determination High (sound) Cold (thirst) Consecutive (Appetite)
Cognition Smell Inner Vision Smell
Brain Active Passive Active
Environment Markets (External/Observer) Caves (Selective/Observed) Mountains (Observer)
Motivation Need Hope Innocence
Trajectory Master Anti-Theist Observer

(There are more elements in a chart, but I’m only looking at aspects I’ve explored/understand at this time.)

My human design chart based on tropical astrology (calculated via Genetic Matrix)

My human design chart based on sidereal (Vedic) astrology (calculated via Genetic Matrix)

The chart you’ll see below is based on “true sidereal” or “cosmic” human design. You can calculate your cosmic human design chart for free with this link. Note: It’s best done on a laptop or desktop. The site is not really mobile friendly. **ALSO triple check your UTC time. The UTC calculator linked on the site asks you to specify the exact date you’re calculating it for via the calendar (i.e. your birthdate). I totally missed this my first go, and it does change how your chart is calculated!**

This is my human design chart based on true sidereal / cosmic human design, calculated via this site.

My Thoughts

The similarities

In the first two charts, my type comes out as a projector with splenic authority, and single definition

This has felt true for me for a long time, but I wonder if I’ve been over-identifying with the projector type.

My head and ajna centres have remained open, as has my solar plexus. My heart centre is open in the vedic sidereal and true sidereal charts.

That pretty much sums up everything that’s stayed the same. Type itself is maybe the biggest part of the chart, so overall, things feel pretty familiar.

The differences

While my open centres remained open, the vedic sidereal chart shows that I have one new open centre: the heart/will centre. This actually makes a lot of sense, because so much of my journey (and the things I talk about now on social media), have to do with worthiness, which is a big theme of an open heart centre. This centre is still open in my true sidereal chart, and yep, still makes sense.

My gates are pretty much all different, and I won’t go through each one, but I will say that after reading about each one, some of them feel SO true and totally me.

Type and Authority

Obviously the BIG shift is from projector, a non-sacral being, to manifesting generator, a sacral being.

Projector felt really true for me for a long time. It’s definitely a mental shift to start thinking and experimenting with being an MG.

But, here’s the thing. MGs (and generators) don’t have unlimited energy all the time for everything. They have energy for what lights them up. For the things they love.

I can see how an MG might feel like a projector if they were, say, in a job they didn’t want to be in. From what I understand, MGs and generators will just feel depleted if they’re spending all their time and energy on things they don’t love – and then they have no time for the things they DO love.

I also read that if MGs and generators are not living correctly and are on the incorrect path, they can’t just flip a switch and change course. They need to stop completely. 

And that’s exactly what I did after I left my job. And then again when I quit my photography business. Complete stops.

For my authority, I actually don’t see a big a difference between splenic and sacral. They’re both in-the-moment, “gut instincts” (whether or not the actual gut is involved or not).

So, while they are different, I don’t think it’s such a big mental shift to go from one to experimenting with the other.

Also, without going into too much detail in this already very long post, I recently (March 2021) had an experience that I imagine is what it feels like to respond as an MG. So, as I start this MG experiment, I’m reflecting on this experience (which went snap-crackle-pop and fell into place super quickly and smoothly, so it feels like it aligned in some way, either based on strategy/authority, or something else).


I used to have two channels through the spleen centre (26-44 – Surrender and 28-38 – Struggle) and now I have one: the 18-58 channel – “Judgement.”

The Channel of Judgment is purely projected, meaning it serves best when others ask for it. It contains the intuitive and energetic ability to make things correct in order to create a perfect expression of the Joy of Life (humandesign.tools).

I’m very into joy, and creating and living a joyful life, so that checks out. Further:

This energy is also exceptionally difficult for Projectors. The bottom line of this channel is that in order to be heard and for you to have the platform to correct in a “correct” way, you MUST wait for recognition if you have this channel. If you do not wait, then you run the risk of being perceived as critical by others and no one likes to be criticized. The beauty of this channel is that the correction in the 18 leads to the 58, the Joy of Life. When the 18 waits to be recognized, they clear the path for the perfected expression of the Joy of Life…humandesign.tools

So, doubling down on the “waiting for the invitation” projector strategy it seems.

Going back to the two channels in my tropical chart for a second…

26-44 – Surrender:

  • This channel is about improving upon old concepts and replacing the old with the new. It’s also called the “channel of the entrepreneur” (LOL because I quit my business 😂) for its ability to recognize what will appeal to others.

28-38 – Struggle

  • This channel is about the struggle to find purpose, and the deep sense of searching for that. I generally “struggle” with the concept of “purpose” because I think our current use of it in society doesn’t quite make sense, but I don’t know if as a person, I really feel the need to have my own individual purpose (beyond truly enjoying life), ALTHOUGH I have thought I needed one in the past, which is a whole discussion we could get into.

In my true sidereal chart, I now have five channels:

2-14 The Beat:

  • This channel is about having (14) and managing resources (2). Gate 14 is about “power skills” and important social connections the things we think of when we think of wealth. (Understanding Human Design, Karen Curry). All in all, I’m definitely happy to have this channel (in true sidereal HD).

10-34 Awakening/Exploration:

  • People with the 10/34 merely need to act correctly in response in order to demonstrate power. There is no convincing or sharing here. There is no throat center here. This is pure empowerment by being and responding and, as with all individual circuitry, these people can deeply empower others simply by being the purest expression of the self.” (Human Design Tools)

16-48 The Wavelength:

  • This channel represents the intuitive expression of talent blended together with repetition over time…The energy for enthusiasm and depth is contained in this channel. There is right timing in this channel. Do not express the depth with enthusiasm until you are ready…you have practiced and achieved mastery…). (Human Design Tools)

29-46 Discover/Succeeding where others fail:

  • “…anyone with this channel must be careful to commit based upon their sacral response and their Authority. Once committed they will have to finish the experience no matter how long it may take – even years. Remember that in the Abstract circuitry one learns from experience – after the experience is over.They have got to wait until the experience is over to be able to see if anything was discovered. While it is happening you can only follow your strategy.In the big picture, no matter what happens, through failure and success if you are following your strategy you will always be in the right place at the right time because you will come out of it with the right kind of experience that you can share.” (Human Design Tools)

32-54 Transformation:

  • The 32-54 has the drive to get ahead but it understands that to succeed it must have the support of others. This channel knows that only a transformation that endures over time has value, and in order for the change to endure it must have the support of its tribe…the 32-54 is a projected channel that needs to be recognized and invited.” (Human Design Tools)

I don’t have much to say about these yet, but I’m eager to learn more about the 2-14 channel, AKA the WEALTH channel, as I’m choosing to call it

Let’s move onto profile

My tropical astro HD profile was 4/6 – Opportunistic / Role Model.

My sidereal profile is 2/4 – Hermit / Opportunist.

My true sidereal profile is 6/3 – Role model / Martyr.

So, I guess technically parts of my profile are similar.

I most resonated with the 4/Opportunist part my tropical HD chart. This line is less about being greedy and manipulative (though I guess it could show up that way), and more about realizing opportunities through your network.

Looking back at various opportunities I’ve had, many of them have come through my network and relationships in some way.

Whenever I read about the 6 line, it always seemed like it didn’t really come into play until the last third of your life, when you emerged as a role model from your life experiences. Because of that, I always just kind of ignored it because it didn’t have relevance “today” 🤷.

Now, the 2 line (as per my vedic sidereal chart) – this is someone who needs their alone time to cultivate their skills and interests (which also sounds very projector-y…or like a mountains environment person. More on that below.). As you can imagine with the archetype of “hermit”, someone with this line likes to be comfy and cozy and is a bit of a homebody. But not JUST a homebody – more like an introvert/extrovert combo (Emma Eklund) (also like mountains people).

Aaaand, in terms of my true sidereal profile of 6/3, people with this profile “…are bound by a need to learn from experience.”

The 3rd line is experimental and experiential. They have to try something to know about it and can’t just hear or learn about it from someone else’s experience.

I can definitely see how this could be descriptive of my life thus far (and the 6 line acts like a 3 until your Saturn return, so really it’s like I would have been a double 3 line).

Moving onto determination

My tropical astro HD chart shows high (sound), and my sidereal astro HD chart shows cold (thirst).

I just shared in my IG stories about how I’m experimenting with my determination and having sound whenever I eat. My tropical chart also showed an active (left-facing) digestion arrow (top left), which suggests regular, consistent meals.

Now, I actually have found that my digestion has improved by being more conscious of my “high sound” determination; however, hold that thought, because I have a theory.

My sidereal determination is cold (thirst) with a passive (right-facing) digestion arrow. This means I would benefit from eating things cold and/or raw (i.e lots of uncooked veggies and fruits), and from having (cold) liquids with me – and always staying hydrated (but, hey, we all could benefit from that!).

So, first, I literally always have multiple liquids around me. I usually have tea, my water, maybe a shake or smoothie, etc.

The tea starts hot, of course, but I always, always drink it slowly. This means that for most of my tea-drinking experience, the tea is luke-warm or on the cooler side.

Passive digestion means eating more intuitively – when you feel like it – rather than regular, consistent meal times. 

During my experimentation, I tried to eat more regularly and consistently, with a bunch of smaller snacks and meals throughout the day. But, honestly, I find that exhausting. It’s like, constantly thinking about food.

Thinking back to my high school, university, and office life days, I would always have loads of snacks packed/with me in case I got hungry. I was naturally planning to eat intuitively. Sometimes I’d eat all my snacks, sometimes not. The thing is, I didn’t know how much I would want, so I’d pack for “just in case.” Without realizing it, I was catering to intuitive, passive eating.

Since first writing this article (mid-Feb 2021), I experimented with cold determination, and you know what…it’s not for me. And I suspected that before trying it, because I’ve just naturally always been drawn to warmer food, especially drinks. BUT, I did the experiment.

My true sidereal determination is appetite, consecutive. This boils down to eating really simple. Simple, nutritious ingredients – and eating one thing at a time. I generally prefer simple (natural) ingredients, anyway, so I may have been doing this subconsciously already (and yes, I WAS doing this with my high school lunches).

Mixing in cognition

My chart went from a smell cognition (tropical) to an inner vision cognition (vedic), and back to smell.

Smell cognition is like literally being able to “sniff out a rat” or “smell something fishy,” but it’s also needing to enjoy the actual smells around you. And, when living “correctly” this is the sense that would become strengthened. It’s like a super sense – the ability to sniff out hidden, energetic frequencies (this was from Vaness Henry’s old blog – her new blog is now up but hasn’t yet been updated with all the old content).

Inner vision cognition is more about mindfulness and the actual vision you have for yourself and your life – like visualization in manifestation lingo. Plus, one of your highest potentials with this cognition is “the gift of sight” (Vaness Henry).

Vaness Henry uses the example of mindfully eating a single raisin, and really savouring it, to explain inner vision (Vaness Henry’s old subscriber content) and the idea that you need time away to really clarify your big vision (Vaness Henry).

Honestly, I did feel a bit of “aw, shucks” during this month of experimenting with inner vision as my cognition versus smell. One is not better than the other, but I had this feeling that smell made sense. That it was mine. Going “back” to smell with my true sidereal chart feels like a relief in some ways (but also might just feel that way because I’m already familiar with it).

Environment time!

My tropical astro HD chart environment was markets with a right-facing (external/observer) environment arrow. I literally just published a blog post about coping with the pandemic as a markets external person, which I won’t delete, but will definitely need to update (in case you haven’t noticed, my “new” chart feels more true for me).

I actually really liked the idea of markets. I liked what it meant – and it matched the vision I had for myself (i.e. living in the centre of a cute, European city, observing the bustle of activity).

Markets people like having choices and options, and being able to be selective. The right-facing arrow indicated more fluidity with one’s environment, like lots of travel, and changing up your environment often. For markets external people, the right-facing arrow also means your environment should relax you.

My vedic sidereal environment is caves selective (observed/left-facing arrow). This means my correct environment should bring out my activity. This doesn’t necessarily mean I’ll feel like being physically active, but it will encourage whatever “activity” I’m drawn to (like, right now for example, it’s writing this lengthy blog post).

The caves environment is about feeling safe, secure, and cozy (like a hermit??). In any particular room, for example, having one door or one entrance would be ideal, and a caves person would want to face that entrance.

I do actually find that I really dislike being on packed public transit (pre-covid), in the middle of a crowd of people, with people behind me. In this case, I prefer to tuck myself into a corner, near the doors, so I can easily escape/get off the bus/train/etc.

In my room and for my sleeping position, I must be able to see the door from my bed, though needing the door closed hasn’t felt as important for me (also I have cats, and I need them to be able to get in and out at night). 

With my true sidereal/cosmic HD chart, my environment is mountains (observed/left-facing arrow). So this means my correct environment will bring out my activity. Reading about the mountains environment had me feeling a real big “Hell yes!” This feels true.

Even as I write this little update (March 15, 2021), my back is to my condo door (caves people would hate this). But I’m looking out the window from the fourth floor of the building (mountains-y).

Caves did not feel right during my 1-month experiment with my vedic sidereal HD chart. So much so, that I ignored this part of the chart.

Also, I really don’t like being in basements. Or underground parking. I need more of a view. More of an elevated perspective (mountains).

Um, but wait, didn’t I say I really resonated with my tropical HD markets environment? Well, yes – because of what I thought it meant for me. Being in the middle of a bustling, European city.

And mountains people? They like to travel a lot (same). They need to get away to get perspective (same). To escape. AND ALSO, mountains people may really like to sing. In the car. This is actually one of my favourite activities. It feels so therapeutic!

And actually, for the sake of experimentation, let’s just say my MG chart feels right for me – mountains people like being around people, but then need to get away and spend time on their own. This behaviour is definitely true for me, and is also similar to a projector with a markets environment, which could be why those things felt true for me, too.

I’m learning more about motivation, too

Since I’m just starting to dive into this aspect of human design, I haven’t really experimented much with it.

My tropical HD motivation was need, with the master trajectory, which meant responding to or meeting a need. I would be motivated to act based on the need for something. The trajectory piece is about starting out as a novice, and becoming a master in something.

My vedic sidereal HD motivation is hope (with an anti-theist trajectory), which is more about moving toward something based on the trust that it’s right for you. It’s based on a sense of knowing, without really being able to explain why. You don’t need proof, and it doesn’t need to make logical sense, but you know you have to do it. You don’t need to push or force it to work (Vaness Henry’s old subscriber content). The trajectory is about starting within a “rigid” belief system, and moving toward anti-theism, or “away” from a rigid belief system. I don’t think this means that you don’t believe in anything, but it’s more about moving toward believing and trusting in yourself, rather than seeking answers outside of yourself.

I can see how the hope motivation could have played out in past events and decisions (i.e. walking away from an au pair job in Paris with no plan but to stay in Europe for 3 months, and quitting my 9-5 job then subsequently quitting my business just because I knew I had to…).

My true sidereal HD motivation is innocence with an observer trajectory. This was the second piece of my true sidereal HD chart that felt like a lightning bolt in my gut.

Every single time I read about my tropical incarnation cross (RAX Rulership 4), I kept thinking…maybe there’s another way to “rule” or lead? Maybe I can just do it as a role model? Lead by example?

And you know what the motivation of innocence (Vaness Henry’s old subscriber content) is NOT about? Ruling. Leading. Persuading/manipulating. The innocence motivation with the observer trajectory is actually about just BEING and being a role model by example – by how you’re being and living your life. The observer part means literally observing what’s happening around you and in the world, taking that in, and learning from that, and adopting what makes sense to you (vs observed, which would mean you’re more on the frontlines and more of a visible/vocal/active example/role model).

Seriously, I was like, “HOLY CRAP!” So, needless to say, my true sidereal HD motivation feels more like a remembering of who I already am (reminder that you already KNOW, you don’t really need a chart…but I still love HD). It feels true for my life so far and for what I actually want for my life.

The final piece is the incarnation cross

My tropical HD incarnation cross was Right Angle Cross (RAX) of Rulership 4. My vedic sidereal HD incarnation cross is RAX Contagion 4 (umm, contagion??). My true sidereal incarnation cross is Left Angle Cross (LAX) of Defiance 2.

To be really honest, I’ve never felt connected to the whole RAX Rulership thing. As a result, I’ve just never thought much about it, or looked into a whole lot. I was kind of like, “Hmm, interesting, I guess we’ll see…” and then put it out of my mind.

RAX Rulership 4 says that your life theme is to rule – that people naturally look to you as a leader, as the one with the knowledge and resources to take charge (The Book of Destinies).

It also says that, “promoting leadership comes easy to you and is readily accepted by those whom you wish to impress” (The Book of Destinies).

This, to me, feels off. However, I allowed for the possibility that my life could play out that way, especially with the 6 line in my (old) profile.

On the other hand, the RAX Contagion 4 incarnation cross suggests a “life theme of transference with the means to convey concepts of potential interest to almost everyone… Being aware of your desires opens you to experiences that expand your senses, and it brings you into intimate contact with life as you transform the lives of others, regardless of whether you are aware of your effect… You are the quintessential torchbearer who loves to inspire others to pay attention to assets and ideals that resonate with you” (The Book of Destinies).

It goes on to say, “With your conscious Sun in gate 14, you have the ability to recognize things of substance and deal with them in a way that makes them interesting and useful. You can draw people to you, combining everyone’s interests in matters of wealth and prosperity. Appreciating the merits of opulence, and often prioritizing that side of your life, you have the ability to commit yourself to almost anything that comes along and make it grow and flourish” (The Book of Destinies).

(P.S. This description also reminds me of the innocence motivation – impacting others by example, whether you’re aware of it or not.)

The LAX Defiance 2 incarnation cross says that:

“Your Cross brings the energy that stands up to controlling influences. You are here to embody self expression. There will be people that attempt to impose rules of just how you can do that. Your energy is to defy those rules because how can anyone put bounds on self expression? You are here to make sure your expression has a voice and no one can box that in.” (Human Design Tools)

This has literally been my life. Figuring out how I want to express my self and giving that part of me a voice. I don’t have it all figured out yet. For example, I’m still experimenting with my personal style and how I want to express myself on line and through this blog, but it’s a journey of self-discovery.

Reading the LAX Defiance 2 description, I felt this instant recognition, like, “Yep, that’s it.”

To Conclude

I still have a lot to learn, and so much more to experiment with. Despite all of this information, I still feel like I’m just barely scratching the surface of human design.

I’ve shared a bit about how my HD chart differs between tropical, vedic sidereal, and true sidereal astrology, and so much has changed going to true sidereal/cosmic HD!

I definitely feel more drawn to my chart with true sidereal astrology. I may eventually write more about my gates in different posts, but based on my initial brief read of each gate, so many of them feel accurate (also a reminder that we all have the whole HD chart, it’s just that some parts are active or “turned on” for us, like genes).

I’ll be experimenting with my true sidereal/cosmic HD chart. Honestly, my biggest hurdle right now is mental. I “was a projector” for almost two years. I’m familiar with what that means.

To be fair, I think learning I was a projector when I did was exactly what I needed at the time. It gave me a map to say no to things (work) that didn’t light me up. It allowed me to rest, A LOT, which is what I needed.

But maybe I don’t need that anymore? (MGs and generators still need rest, and don’t have energy for things that DON’T light them up – which could also be why I felt so much like a projector 1-2 years ago.) Anyway, so much to experiment with!

If you happen to look into how your chart differs, experiment for yourself and see what feels best.

Regardless of which version you use, you are not your chart. Your chart is a tool. Human design is a tool. Maybe it helps you describe or understand your reality better, and that’s great, but at the end of the day, trust yourself and your own intuition.

P.S. Click here to read more of my popular human design posts.

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