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Education · head to head

Stellarium vs Udemy

Stellarium logo

Stellarium

Education

Free open source desktop planetarium software, distinct from the paid Stellarium Mobile Plus app

From
Free
Rated
-
Full reviewWebsite
Udemy logo

Udemy

Education

World's largest marketplace for online learning

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Stellarium it is desktop-only software, so it has no native touch-optimised phone interface; the similarly named mobile app is a different paid product from a different company.; Udemy course quality varies significantly as Udemy allows anyone to create and sell courses without vetting
  • They diverge on capability: Stellarium covers Photorealistic sky rendering, Udemy covers Video courses.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Stellarium and Udemy actually diverge.

Attributes where Stellarium and Udemy differ
AttributeStellariumUdemy
Pricing modelOpen source, no licence feeUnknown
PlatformsWindows, macOS, LinuxWeb, iOS, Android
FoundedUnknown2010

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Education).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Stellarium

  • Photorealistic sky rendering
  • Large object catalogue
  • Telescope control
  • Scripting engine
  • Free and open source
  • Plugin ecosystem

Only in Udemy

  • Video courses
  • Quizzes
  • Assignments
  • Certificates
  • Mobile learning
  • Offline viewing
  • Q&A
  • Reviews

What people use each for

The jobs each tool is most often brought in to do.

Stellarium

  • A student or educator wanting a serious, scriptable planetarium tool without a budget line itemnot Udemy
  • An amateur astronomer wanting telescope control from desktop software they can inspect and modifynot Udemy
  • Someone running a planetarium display or public astronomy event on a scripted shownot Udemy
  • A hobbyist who wants a large object catalogue without paying a subscription, and does not need a phone appnot Udemy

Udemy

  • Skill buildingnot Stellarium
  • Career transitionnot Stellarium
  • Professional developmentnot Stellarium
  • Team trainingnot Stellarium

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Stellarium

  • It is desktop-only software, so it has no native touch-optimised phone interface; the similarly named mobile app is a different paid product from a different company.
  • As a volunteer-maintained open source project, support is community-based rather than a guaranteed commercial help desk.
  • The interface, while capable, is less immediately intuitive for a first-time user than a polished commercial phone app.
  • Telescope control and some advanced plugins require additional setup that a non-technical user may find fiddly.
  • Because it shares a name with the unrelated paid Stellarium Mobile Plus app, buyers researching pricing online can easily conflate the two products.

Udemy

  • Course quality varies significantly as Udemy allows anyone to create and sell courses without vetting
  • No formal credentials or degrees offered, unlike Coursera and edX which offer institution-branded certificates
  • Courses are self-paced with no instructor interaction or support, making structured learning difficult for some students

Pricing, plan by plan

Stellarium

Free
  • Stellarium DesktopFree
    • Full software, GPL licensed
    • No account, ads or subscription
    • Community-developed plugins

Udemy

Free
  • Personal$19/month
    • 11,000+ courses access
  • Team$360/year
    • For 5-20 people

Which should you pick?

Choose Stellarium if

  • You need photorealistic sky rendering.
  • You want to start without paying.
  • You work on Windows, macOS, Linux.
  • You also want large object catalogue.
Stellarium review

Choose Udemy if

  • You need video courses.
  • You want to start without paying.
  • You work on Web, iOS, Android.
  • You also want quizzes.
Udemy review

Questions people ask

Is Stellarium or Udemy better?
Neither clearly leads. Stellarium starts at Free and Udemy at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Stellarium or Udemy?
Stellarium starts at Free and Udemy at Free.
Does Stellarium or Udemy run on more platforms?
Stellarium runs on Windows, macOS, Linux. Udemy runs on Web, iOS, Android.
Can I use Stellarium for free?
Both have a free tier, so you can try either at no cost before committing.
What is Stellarium best used for?
Stellarium is most often used for a student or educator wanting a serious, scriptable planetarium tool without a budget line item, an amateur astronomer wanting telescope control from desktop software they can inspect and modify, someone running a planetarium display or public astronomy event on a scripted show, a hobbyist who wants a large object catalogue without paying a subscription, and does not need a phone app. Of those, a student or educator wanting a serious, scriptable planetarium tool without a budget line item and an amateur astronomer wanting telescope control from desktop software they can inspect and modify are not what Udemy is typically brought in for.
What can Stellarium do that Udemy cannot?
Stellarium covers Photorealistic sky rendering, Large object catalogue, Telescope control, Scripting engine. Udemy covers Video courses, Quizzes, Assignments, Certificates.

Answered from the vendors’ own pages

Stellarium: Is Stellarium really free?

The desktop software is free and open source under the GPL licence. The separate mobile app, Stellarium Mobile Plus, is a different paid product.

Udemy: Does Udemy offer team/business pricing?

Yes, Udemy's Team plan costs $360 per user annually for groups of 5 to 20 people, in addition to individual Personal plan at $19/month.

Source
Stellarium: Is the mobile app made by the same team?

No. Stellarium Mobile Plus is built by Noctua Software, a different company, and is sold on subscription.

Stellarium: What platforms does the free version run on?

Windows, macOS and Linux desktop.

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