# Day 33 · A position needs a steady reference

**Child start:** “Keep the frame steady. Move the marker or tell someone where it goes. Which notes can we compare?”

**Useful finish:** A reference instruction a helper can follow. **Prerequisite:** Day 17 horizon/background distinction; model position not real distance. **Prepare:** Paper frame labelled left/centre/right; same triangle of three arbitrary star markers; spare frame with a different origin. No real constellation names. **Opportunities:** U01/I02(plan)/I03(model)/I04/I05/I06.

**Complete model:** Fictional frame F uses a tree-outline mark on its left and a low wall-outline across its base. At model time A an invented star triangle is above the left mark; at time B the same intact triangle is above the centre. F stays fixed. Record C uses a moved/different frame G and only says “above left”; no mapping between F/G is given. Compare A/B against F; C's word “left” does not by itself establish the same sky position. Star separations/real distances were not measured.

**Run:**2 min choose a question for a reader;3 min demonstrate leaving F fixed and moving the whole triangle;7 min selected route;3 min ask what was held as reference and why C cannot be compared directly. Extend by helper rehearsal4 min, repair3 min, communicate one method3 min.

**Route1 — Direct a paper observatory:** Child gives the sequence for frame/triangle placement, then names what changed. This is actual paper modelling, not night observing. **Route2 — Compare notebooks:** Circle the named references in A/B/C; keep usable data and ask for the missing F/G relation before comparing C. **Route3 — Make tactile or spoken instructions:** Use broad raised paper edges if locally suitable or verbal frame labels; child supplies a fixed-reference instruction to a willing helper. No tactile-contact requirement.

**Notice/next:** Object/reference/time must stay attached to the position. If frame moves unnoticed, fix it and replay one paper placement. If child claims stars do not move in space, clarify only the short model arrangement stays fixed. Home H03; C05–06; X03.

## Ready doors

[Ordinary example C05](../ordinary/C05.html) · [Another example C06](../ordinary/C06.html) · [Home H03](../home/H03.html) · [Project X03](../extras/X03.html) · [Read-aloud](../readaloud/day-33.html) · [Paper and picture aids](../aids/START.html) · [Sky Desk](../interactive/index.html)

[Participation and preparation](START.html) · [Mapping](CURRICULUM.html)
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