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Education · head to head

Gaggle vs Stellarium

Gaggle logo

Gaggle

Education

Human-reviewed student safety monitoring across school email, documents and drive files

From
On request
Rated
-
Full reviewWebsite
Stellarium logo

Stellarium

Education

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

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Stellarium has a free tier, so it costs nothing to try first.
  • Each has a real cost: Gaggle pricing is quoted per student per year with no published rate, and because it is charged on total enrolment rather than on accounts actually monitored, small districts pay a markedly higher effective rate than large ones.; 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.
  • They diverge on capability: Gaggle covers Content scanning, Stellarium covers Photorealistic sky rendering.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Gaggle and Stellarium actually diverge.

Attributes where Gaggle and Stellarium differ
AttributeGaggleStellarium
Starting priceOn requestFree
Pricing modelquoteOpen source, no licence fee
Free tierNoYes
PlatformsWebWindows, macOS, Linux

Identical on both: 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 Gaggle

  • Content scanning
  • Trained human review
  • Phone escalation
  • SpeakUp for Safety
  • Web filter safety integration
  • Incident reporting
  • Google and Microsoft coverage
  • District-scoped contacts

Only in Stellarium

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

What people use each for

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

Gaggle

  • A district whose board has adopted a suicide prevention policy that requires someone to act on a written disclosure within hours, at any time of yearnot Stellarium
  • A district with no counselling capacity to triage automated alerts and that would otherwise ignore themnot Stellarium
  • A district already running a web filter that produces safety signals nobody reads, wanting them routed to a staffed review servicenot Stellarium
  • A district responding to a specific incident where a warning sign existed in a student document and nobody saw itnot Stellarium

Stellarium

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

Where each one falls short

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

Gaggle

  • Pricing is quoted per student per year with no published rate, and because it is charged on total enrolment rather than on accounts actually monitored, small districts pay a markedly higher effective rate than large ones.
  • False positives are structural, not a tuning problem: fiction assignments, song lyrics, health coursework and jokes between friends all trigger review, and each escalation consumes counsellor time the district funds itself.
  • The service reads children's private writing on school accounts, and civil liberties groups have documented cases where flagged content led to outing LGBTQ students or to discipline rather than support, which is a governance risk a board must accept explicitly.
  • Coverage is limited to district-issued accounts, so a student using a personal phone, a personal email address or an encrypted messaging app is invisible, which is where much of the behaviour the district worries about actually happens.
  • Escalation depends on the district maintaining accurate contact lists and staff who answer calls; when a named contact leaves and the list is stale, the service escalates into a void and the district only discovers it after an incident.

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.

Pricing, plan by plan

Gaggle

On request
  • Gaggle Safety Management$undefined/year
    • Machine plus human review of student email, documents and files
    • Escalation to district contacts including out of hours
    • SpeakUp for Safety tipline included

Stellarium

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

Which should you pick?

Choose Gaggle if

  • You need content scanning.
  • You also want trained human review.
Gaggle review

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

Questions people ask

Is Gaggle or Stellarium better?
Neither clearly leads. Gaggle starts at On request and Stellarium at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Gaggle or Stellarium?
Stellarium has a free tier; the other does not. Paid plans start at On request for Gaggle and Free for Stellarium.
Does Gaggle or Stellarium run on more platforms?
Gaggle runs on Web. Stellarium runs on Windows, macOS, Linux.
Can I use Stellarium for free?
Yes. Stellarium has a free tier, so you can try it without paying. Gaggle starts at On request.
What is Gaggle best used for?
Gaggle is most often used for a district whose board has adopted a suicide prevention policy that requires someone to act on a written disclosure within hours, at any time of year, a district with no counselling capacity to triage automated alerts and that would otherwise ignore them, a district already running a web filter that produces safety signals nobody reads, wanting them routed to a staffed review service, a district responding to a specific incident where a warning sign existed in a student document and nobody saw it. Of those, a district whose board has adopted a suicide prevention policy that requires someone to act on a written disclosure within hours, at any time of year and a district with no counselling capacity to triage automated alerts and that would otherwise ignore them are not what Stellarium is typically brought in for.
What can Gaggle do that Stellarium cannot?
Gaggle covers Content scanning, Trained human review, Phone escalation, SpeakUp for Safety. Stellarium covers Photorealistic sky rendering, Large object catalogue, Telescope control, Scripting engine.

Answered from the vendors’ own pages

Gaggle: How much does Gaggle cost?

It is quoted per student per year based on enrolment and requirements. No rate card is published, and effective rates fall substantially with district size.

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.

Gaggle: Is the tipline an extra charge?

No longer. From 1 July, districts on the full Safety Management solution get SpeakUp for Safety and the web filter safety integration at no additional cost; each previously carried a per-student charge.

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.

Gaggle: Do humans read every alert?

Trained reviewers assess flagged items before escalation. That human layer is the core of the service, not an optional tier.

Stellarium: What platforms does the free version run on?

Windows, macOS and Linux desktop.

Gaggle: Does it monitor personal accounts or phones?

No. It covers district-issued Google or Microsoft accounts. Personal devices, personal accounts and encrypted apps are outside its reach.

Gaggle: What are the privacy obligations?

Districts sign a data processing agreement covering FERPA and applicable state student privacy law. Negotiate retention and scope in that document rather than relying on the marketing page.

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