Comparison · Updated July 2026

Astrologer vs Sirius / Kepler

Sirius and Kepler, from Cosmic Patterns Software, are among the most feature-dense professional astrology programs available — large interpretive report libraries, research and statistical tools, and broad technique coverage, with Sirius as the flagship. They are one-time-purchase Windows programs. Astrologer brings broad chart and timing work to any browser, with live AI and client-practice tools instead of a fixed report-and-research focus.

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Sirius / Kepler at a glance

Cosmic Patterns’ flagship professional Windows programs, known for vast report and research libraries.

Maker	Cosmic Patterns Software (USA), led by David Cochrane. Current versions listed by the maker: Sirius 4.1 and Kepler 9.0.
Platforms	Windows desktop only (Mac via emulation). No native web or mobile.
Pricing	Sirius $550 and Kepler $300 one-time; optional report, chart-data, rectification, and other add-ons cost extra.
Calculation engine	Swiss Ephemeris.
Best for	Professional and research-minded astrologers on Windows who want exhaustive reports and statistical tools.

Feature comparison

Feature	Astrologer	Sirius / Kepler
Vast interpretive report library	AI + interpretation	Yes — its hallmark
Research / statistical tools	Limited	Yes — a real strength
Runs in any browser, any device	Yes	No — Windows install
Works fully offline	Needs a connection	Yes — once installed
Price	Free tools / $26 Practitioner	Sirius $550 / Kepler $300
AI readings from your chart	Yes (paid plans)	No — fixed report text
Astrocartography + relocation	Yes	Yes
Profections, progressions, returns	Yes	Yes — extensive
Synastry + composite	Yes	Yes
Live sessions + community + Academy	Yes	No
Calculation engine	Swiss Ephemeris	Swiss Ephemeris

Where Sirius / Kepler wins

Among the largest interpretive report libraries in any astrology software.
Genuine research and statistical tooling that few other programs match.
A dedicated, deeply customizable desktop program that works fully offline.

Where Astrologer wins

Runs in any browser on any device — no Windows, no install, no license key.
Free public tools plus a browser workspace, versus a Windows license and optional add-ons.
Live AI readings generated from your specific chart, instead of a fixed report library.
Cloud-saved charts, practitioner sessions, a community, and a built-in Academy.

The bottom line

If you want very large fixed report libraries and real statistical research tooling on Windows, Sirius and Kepler are hard to beat. If you want live chart-grounded AI, cross-device access, learning, and a client-practice suite, Astrologer is the more integrated workspace.

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Frequently asked questions

What is the difference between Sirius and Kepler?

Both are Cosmic Patterns programs; Sirius is the flagship with the most features, and Kepler is the step below it. Astrologer compares favorably to both for everyday browser-based work, while they go deeper on reports and research tools.

How do Astrologer, Sirius, and Kepler pricing compare?

Sirius is $550 and Kepler is $300 as one-time Windows licenses, before optional add-ons. Astrologer has free public calculators; Practitioner is $26/mo or $260/yr and bundles the studio with AI, Academy, and practice management.

Do Sirius and Kepler run on Mac?

They are Windows programs and typically need emulation on a Mac. Astrologer runs in any browser, so Mac, Windows, Linux, tablets, and phones all work natively.

Does Astrologer have research tools like Cosmic Patterns software?

Not to the same degree — statistical research is a genuine strength of Sirius and Kepler. Astrologer focuses on chart work, timing, interpretation, and AI readings rather than statistical research.