Understanding Astronomy Parallax Distance
How we calculate. Distance in parsecs = 1 ÷ parallax in arcseconds. The form uses the same arithmetic as the worked examples on this page. See our methodology and accuracy policy.
Real-world scenario: Parallax p = 0.1". Use those inputs in the Astronomy Parallax Distance form to verify the on-page formula.
What is Astronomy Parallax Distance?
A basic stellar-distance KPI. Distinct from redshift distance and distance modulus.
- p in arcseconds
- d in parsecs
- Small-angle teaching model
The Formula
Worked Example
Common Use Cases
- Homework: stellar distances
- Lab: parallax worksheets
- Study: pair with distance modulus
Pro Tips
- Enter arcseconds, not mas (convert mas÷1000)
- p must be > 0
- Don’t use for cosmological z
Limitations: Astronomy Parallax Distance results are educational astronomy study aids—not navigation, mission planning, or professional observing advice. Confirm constants and units with your textbook or instructor.
FAQ
What if parallax is in milliarcseconds?
Convert to arcseconds first (mas ÷ 1000).
Same as distance modulus?
No. Distance modulus uses magnitudes; this page uses parallax only.
Authoritative References
For astronomy study concepts, consult:
- OpenStax Astronomy — free textbook reference
- NASA — mission and outreach context
- IAU — astronomical constants and naming