Posted by: Isidora | August 1, 2011

When does Sirius, the Star of Isis, rise in your area?

The ancient Egyptian New Year began when the spectacularly brilliant star Sopdet (Sothis in Greek; Sirius in Latin) was seen to rise before the sun in the early morning. This is known as the heliacal rising of the star. During part of the year, you see, Sirius is so close to the sun that the greater solar light blots out the light of the star and the star seems to disappear from the sky. The heliacal rising is the day that the sun and Sirius are once more far enough apart that—for the first time in months—Sirius may be once again seen in the pre-dawn skies. From at least the time of the Pyramid Texts, the beautiful star Sopdet was associated with the beautiful Goddess Isis. Sirius is the holy star of Isis and you can look for Her heliacal rising sometime this month.

Sirius, the beautiful Star of Isis, photographed by Monarch with a telescope from the Canary Islands.

To the ancient Egyptians, the rising of Sirius was the herald of the all-important Nile flood, as well as marking the beginning of the year, Thoth 1. Yet the five days just before the heliacal rising of Sirius were important, too. The Egyptian civil calendar (there were a variety of calendars in ancient Egypt) divided the year into 12 months of 30 days each. That, of course, only adds up to 360 days, and the year is 365 (plus a bit, which is why we still need a “leap year” today) days long. The Egyptians knew this, too, so in order to bring the civil year into harmony with the solar year, they added five “days upon the year” or epigominal days to the calendar. On these magical days that were outside of normal time, the Egyptians celebrated the birthdays of Osiris, Horus the Great, Set, Isis, and Nephthys. Plutarch preserved this tradition for us in his essay, On Isis and Osiris, and the divine birthdays are also marked on the ancient Egyptian calendar known today as the Cairo Calendar.

You can see why Isis devotees would want to know when Sirius rises; so that we may celebrate the Birthday of our Goddess in the traditions of the ancient calendar.

So precisely when does Sirius’ heliacal rising occur? Well, it depends on where and when you are located in the world and in time. The further north of the equator you are, the later in the year you will see Sirius rise; and due to the precession of the equinoxes, the date of the star’s rising shifts over time. You will likely be able to see the rise of Sirius sometime this month; exactly when depends on exactly where you are.

You might think it would be relatively easy to find out when such an important star as Sirius rises locally. It isn’t. When I was writing Isis Magic, I even called my local planetarium and they weren’t able to help me. I scoured the internet. I inquired on Egyptian and astronomy lists and forums. But no luck. That was then; this is now. And I am happy to say that I have since found an online calculator—and I’m going to share it with you.

It was designed by a French doctor of astronomy with an interest in ancient Egypt. She offers software for purchase that lets you calculate any star’s heliacal rising. But here’s the good part: you can sample the calculator—on Sirius—for free. Here’s the link. (Put in your email and the password softtests) All you need to know is your latitude and altitude (how much above sea level) and be able to put up with the Google Translate version of the site—unless you speak French, of course.

To find Sirius in the night sky, just look for the constellation Orion, which was associated with Osiris by the ancient Egyptians. The three stars in Orion’s belt point directly at Sirius.

To find Sirius, look to the left of Orion’s belt.



  1. Thank you for the info!! Welcome Back!!! 😉

  2. I’m so happy to see you active again! Sirius becomes visible for me as the weather gets colder. I live in Illinois. I spend time over the winter months gazing on that beautiful star. Great post!


  3. Sirius is also the chest star in Canis Major and directly southeast from me at the moment. I love google star maps. 🙂

    • I KNOW…I love google star maps, too. And iPhone has an even cooler version that has the outlines of the constellations drawn in!

  4. […] rising this coming Tuesday at about 4:30 a.m. PDT, here in Portland. (I wrote about this in a previous post.) The beautiful star’s rise will mark the first day of the new year—in ancient Egyptian […]

  5. […] charge from time to time by repeating the Knot of Isis formula on occasion; perhaps yearly at the rising of Sothis in your area, or monthly on the full moon. A Roman-era version of the Knot of Isis worn by the Goddess or Her […]

  6. […] charge from time to time by repeating the Knot of Isis formula on occasion; perhaps yearly at the rising of Sothis in your area, or monthly on the full […]



  8. Hello, that linked website seems to be down. Any idea how to find the information for this year?

  9. Hi, Laura! Thanks for letting me know. Looks like that link is gone. I found something else to substitute in the meantime. I’m going to make a post on it in a minute here. Thanks again!

  10. Good post. I learn something new and challenging on blogs I stumbleupon every day.
    It will always be exciting to read content from other authors and practice
    something from other websites.

  11. when will it be seen in CAPE TOWN SOUTH AFRICA (ISIS)

  12. Dead link

  13. Hi there so when is the rising of sirrius in Cairo 2014.I got really bad internet connection.otherwise I would look myself thankyou so much

  14. I see no answer when the helical rising of sirrius occurs. It is about July 19th for most places.

    • That’s because there isn’t just one answer 😉 Use the link in the blog post to go to the calculator, enter your email and the password given in the blog post. Then you can enter your location information to see when Sirius rises in your area. When you will see it rise depends upon your latitude. For example, here in Portland, Oregon, Sirius will rise on August 22 this year. The July 19 date was a calculation of its rising in Egypt in about the second century CE.

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