Astrolium versus Solar Fire is the most-asked comparison for working astrologers. Solar Fire dominated desktop astrology for 25 plus years and still ships the most complete classical technique library on Windows. Astrolium is what you switch to when you want to work on iPad, sync across 3 devices, manage clients, and charge for sessions with polished PDF deliverables.
Both programs use the same Swiss Ephemeris core. The differences live in the workspace around the chart. See the full features hub, the predictive timing feature, the synastry feature, or jump to pricing. For all platform comparisons, see the compare hub and TimePassages.
TL;DR — if you run a paid practice
If you are a working practitioner running a paid practice, Astrolium replaces Solar Fire for daily client work — and adds a CRM, modern UI, and live predictive ribbon Solar Fire does not have. Solar Fire is still the right tool for 2 narrow cases: deep-traditional research that needs primary directions, and working without a network connection often. For everyone else, the friction tax of Solar Fire — Windows VM, dialog trees, no client memory, static reports — costs more than the license.
Calculation accuracy — same engine, here is where they differ
Both Solar Fire (since v8) and Astrolium use Swiss Ephemeris as the underlying calculation library. Swiss Ephemeris is a re-implementation of NASA JPL's DE431 ephemeris, accurate to better than 1 arc-second for the period 13201 BC to AD 17191. Planetary longitudes — the numbers most readings actually depend on — are identical in both programs to a precision orders of magnitude tighter than any human eye can read on a chart wheel.
That settles 95 percent of the calculation question. The remaining 5 percent is interesting:
Where Solar Fire is more complete
- Primary directions. Solar Fire offers 6 primary direction methods (Placidus mundo, Placidus zodiacal, Regiomontanus, Campanus, Topocentric, Naibod-key). Astrolium does not ship primary directions today. For most practitioners this is unnoticeable; for hardcore traditional researchers it is a deal-breaker.
- Esoteric chart types. Demi-returns, quarti-returns, Egyptian-Persian charts, parans by latitude — all in Solar Fire, none in Astrolium today.
- Obscure house systems. Carter Poli-Equatorial, Pullen SR, Pullen SD, APC. Not in Astrolium. Almost no working practitioner uses them, but if you do, you will miss them.
Where Astrolium is more complete
- Bound or term tables. Solar Fire ships the older Egyptian table that has minor degree-boundary disagreements with modern Hellenistic scholarship. Astrolium ships Hand/Schmidt by default, with Egyptian and Ptolemaic toggleable in 1 click.
- Zodiacal Releasing. Solar Fire calculates ZR via add-on script only; the L1 and L2 sub-period rendering is not native. Astrolium ships ZR for both Spirit and Fortune as a first-class feature with calendar overlay.
- Asteroids. Solar Fire's full asteroid set is paid extra. Astrolium ships all 20,000 plus named asteroids in every plan, queryable.
- Fixed-star lists. Astrolium ships both the Robson list (49 stars, the traditional set) and Brady's longer list (115 stars). Solar Fire ships its own bright-star catalog.
- Human Design. Solar Fire has no Human Design module — the system sits outside its scope. For practitioners who weave HD into Western readings, Astrolium ships the bodygraph calculator, the type-and-authority compatibility view, and a daily HD transit overlay on the same client profile as the natal wheel.
- Astrocartography as a workflow. Solar Fire's Maps module draws the lines, and stops. Astrolium adds an open-ended city search that ranks cities across 10 life areas for a single chart, and a head-to-head city comparison for the relocation client weighing two finalists. The planetary line map is the entry point; the rest is the working surface most relocation clients actually need.
Cross-check a chart between Solar Fire 9.x and Astrolium and you should see identical positions for the planets, nodes, and angles. Bound rulers may differ in the cardinal signs. Anything beyond that is configuration: different aspect orbs, different default house system. The math is the same.
Workflow — what a session looks like in each
Feature lists do not predict daily life. The right question is: how many clicks, switches, and frictions stand between you and a finished session? The same scenario — a 60 minute predictive consultation with a returning client — modeled in both programs.
Solar Fire 9.x prep — about 9 minutes, 5 apps open
- Boot. Open Parallels (if on Mac), wait for Windows. Open Solar Fire. About 2 minutes.
- Find chart. File → Open chart file → navigate to
Anna_Birth.SFcht. About 30 seconds. - Build tri-wheel. Chart → Multiple wheels → Tri-wheel. Dialog. Pick "today's transits" for ring 3. Click OK. About 45 seconds.
- Find session notes. Switch to your separate Word doc or Google Sheet. Find the row for Anna. Re-read. About 1 minute.
- Run progressions report. Reports → Progressed positions → today. New window opens. About 30 seconds.
- Profections. No native overlay. Compute by hand. About 30 seconds.
- Print or screenshot. Print to PDF for the wheel. Window 2 for the report. Window 3 for progressions. Open Canva to make it presentable. About 3 minutes.
- Session. Screen-share Solar Fire's wheel plus your PDF plus your notes Word doc.
- After. Type session summary into Word doc. Save.
Astrolium prep — about 30 seconds, 1 tab open
- Open browser tab. Astrolium is already loaded. Click Anna's name in the roster. About 3 seconds.
- Anna's panel opens. Last session notes, intake form, every chart you have built for her, all there.
- Tri-wheel is auto-rendered. Natal plus progressed plus today's transits. Default for any client view.
- Profection year is highlighted on the natal — 1st house, Aries, Mars-ruled. Already there.
- ZR period visible in the right rail.
- Drag the timeline scrubber to her birthday this year. Watch Jupiter cross her natal Jupiter live. About 5 seconds.
- Click "share with client" — Anna gets a live link to the chart you will use, before the call.
- Session. Screen-share the 1 tab. Take notes in the same panel. They auto-link to the chart.
- After. Click "send PDF summary" — auto-generated, your branding, in her inbox.
This is not a fair fight on the dimension of "every feature exists somewhere." It is a fair representation of what a working day feels like in each tool. Solar Fire was designed for an astrologer at a desk, alone, before video calls existed and before clients expected a polished deliverable. Astrolium was designed for an astrologer running a small business in 2026.
The thing that surprised early testers: not the modern UI or the CRM. It was the scrubber. Drag a single control and watch profections, ZR sub-periods, and transits all recompute in real time — that interaction does not exist in any other astrology program.
Pricing — what you pay over 5 years
Solar Fire 9 — $360 one-time
- Base Windows license, single machine
- Major upgrade (8 → 9, etc.): $80 to $120
- Add-on modules: $40 to $120 each (Asteroids, Primary directions, etc.)
- Mac users add $99 per year for Parallels or BootCamp partition
- Estimated 5 year total: $520 to $700
No subscription. Owns your data forever (locally). No ongoing cost if you stay on the version you bought.
Astrolium Adept — $29 per month
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$348 per year, all features included, ever
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14 day free trial, no card required
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Estimated 5 year total: $870 over 5 years on annual
Cloud sync. Continuous updates. Cancel anytime — data exports as JSON, .SFCHT, and PDF.
On pure 5 year cost, Solar Fire is cheaper if you are a hobbyist who upgrades every other version and does not run Mac. Astrolium pays for itself the moment it removes one client-handling subscription you currently pay for separately (Calendly, Notion CRM, Canva for PDF reports). For most working practitioners that is day 1.
Migration — moving end to end
Solar Fire data lives in 3 places: .SFcht chart files, .SFchart chart-list files, and your settings or preferences. Astrolium imports all 3.
- Export your chart files. In Solar Fire: File → Save chart as → choose .SFcht. Or, for many at once: File → Save chart file → all charts in current file. Most users just copy the whole C:\Solar Fire\Charts folder.
- Drop the folder onto Astrolium import zone. Settings → Import → drag-drop. Astrolium parses .SFcht, .SFchart, .AAF, and Astro Gold's native format. You see a preview of what is about to be imported, including duplicates.
- Match charts to clients. If your chart names follow a pattern like 'Anna Smith — natal', Astrolium auto-groups them under one client. You confirm or override.
- Verify a sample. Astrolium pulls 3 random charts from your import, renders them in both programs, and shows you a side-by-side. Positions have never disagreed across 14,000 chart migrations.
- Recreate your custom orbs. Solar Fire's Orbs.SFopt file exports. Drop it. Astrolium maps onto its orb book. Anything that cannot be represented is flagged with a recommended substitute.
- Recreate your default page. Solar Fire users have wildly individualized chart wheel layouts. Astrolium has presets that approximate the most common ones plus a layout editor. Bring a screenshot of your typical wheel — the team will match it on a screen-share, free, in your migration session.
- Keep Solar Fire installed for 30 days. Cross-reference your daily reading work for a month. No user has gone back, but the option exists during the transition.
Every new Pro subscription includes a 45 minute migration session with a member of the team. Largest migration completed: 14,000 charts in 4 minutes.
Where Solar Fire still wins
1. You do deep traditional research that needs primary directions
Astrolium does not ship primary directions and likely will not until 2027. If you are working through Morinus or Bonatti and primary directions are central to your method, Solar Fire is still the right tool. We recommend it explicitly.
2. You work without a network connection, often
Astrolium has full offline read but writes need network. If you teach in places without reliable internet — retreat centers, planes, rural areas — Solar Fire's pure-desktop model is more reliable. Full offline write is on the roadmap but not shipped.
3. You are deeply invested in Solar Fire's report designer
Solar Fire's report designer is powerful — you can build wildly custom layouts. Astrolium's templates are flexible but constrained. If you spent years building bespoke reports in Solar Fire, you will feel the constraint. Astrolium's layout editor is in progress but not here yet.
Continue exploring
- Astro Gold vs Astrolium — the native Mac comparison
- TimePassages vs Astrolium — interpretation library vs workspace
- Predictive timing feature — the live scrubber detail
- Pricing — plans, Free tier