The 42nd Period | STEM Education Hub

🎯 Deliverable — Pick a Format

A field guide of ten galaxies, with an identification key at the front. Either format works.

📖 Printed Guide

A folded booklet or a set of pages, one galaxy per page, with printed images and the key on the first page.

💻 Digital Guide

A slide deck, doc, or simple website — one slide or section per galaxy, with the key up front.

Where to find real images:

🌌 The Galaxy Roster

Eighteen real galaxies. Choose ten — click a row to add it to your guide. Your ten must include at least one elliptical, one spiral, one barred spiral, and one irregular, plus one tricky galaxy (⚠). The roster doesn't say which type is which — that's your job.

0 / 10 selected

Galaxy	Also known as	Constellation	Heads-up
M87	Virgo A	Virgo
M49	NGC 4472	Virgo
M32	Andromeda's small companion	Andromeda
M110	NGC 205	Andromeda
NGC 5866	Spindle Galaxy	Draco	⚠ Tricky — seen edge-on
M104	Sombrero Galaxy	Virgo
M31	Andromeda Galaxy	Andromeda
M81	Bode's Galaxy	Ursa Major
M33	Triangulum Galaxy	Triangulum
M51	Whirlpool Galaxy	Canes Venatici	⚠ Tricky — interacting with a companion
NGC 891	Silver Sliver Galaxy	Andromeda	⚠ Tricky — seen edge-on
NGC 1300	—	Eridanus
M95	NGC 3351	Leo
NGC 1365	Great Barred Spiral Galaxy	Fornax
LMC	Large Magellanic Cloud	Dorado / Mensa
SMC	Small Magellanic Cloud	Tucana
NGC 4449	—	Canes Venatici
M82	Cigar Galaxy	Ursa Major	⚠ Tricky — disturbed by a neighbor

The LMC and SMC are best seen from the Southern Hemisphere; the rest can be found in the image archives above. Your selection isn't saved — write your ten down.

📖 Sample Entry — NGC 1073

Every entry needs these fields. NGC 1073 isn't on the roster, so it doesn't count toward your ten.

NGC 1073

FIELD GUIDE · ENTRY 00

SBc

[ image here ] · Credit: ESA/Hubble & NASA

EvidenceA clear straight bar; small bulge; loose, open, patchy arms

What's insideOld stars in the bar and bulge; gas, dust, and young blue stars forming in the arms

Distance~55 million ly

ConstellationCetus

Field noteA good match for the Milky Way's own barred shape, seen face-on.

🧭 Field Tips for Real Images

Start with the big split: smooth and featureless, or does it have a disk? That separates ellipticals from everything else.
Edge-on disks hide their arms. A thin streak with a dark dust lane down the middle is a spiral seen from the side. A smooth streak with no dust is more likely a lenticular (S0).
Look for the bar first, then the arms. If the arms start at the ends of a straight bar, it's SB.
Color is a clue, not a rule. Blue patches mean young stars; smooth yellow means old ones. Image processing can shift colors, so use shape first.
Collisions scramble shapes. A galaxy tugged by a neighbor may look lopsided. Classify what it mostly looks like, and say what's been disturbed.

📋 Content Checklist

Every item below has to show up somewhere in your guide — check them off as you go.

Ten galaxies from the roster, including at least one elliptical, one spiral, one barred spiral, one irregular, and one tricky galaxy (⚠)Each entry: a real image of the galaxy, with its source creditedEach entry: its full Hubble class (e.g. E3, Sb, SBc, Irr), plus at least two visible features as evidenceEach entry: what the class predicts is inside — star ages, gas and dust, star formationEach entry: distance and constellation, looked up from a reliable sourceAn identification key at the front of the guide: a step-by-step way to classify any galaxyA short note on your tricky galaxy: why it's hard to classify, and your best call

📅 Day-by-Day Plan

Day 1

Collect & Classify

Choose your ten galaxies, find a good image of each, and record its source. Classify each one with its full Hubble class and at least two pieces of visible evidence.

Day 2

Write & Key

Fill in each entry: what's inside, distance, constellation, and a field note. Build your identification key, and write up your tricky galaxy.

Day 3

Field-Test & Submit

Give a partner three of your images with the labels hidden, plus your key. If the key leads them to the wrong class, fix the key. Then finalize and submit.

📊 Grading Rubric — 100 pts

A starting point — adjust weights to fit your class before assigning.

Category	Weight	Exemplary	Proficient	Developing	Incomplete
Classification & Evidence	35 pts	All ten galaxies correctly classified, including subclass (E-number or a/b/c), each backed by at least two features visible in the image.	Main types all correct; one or two subclasses off or thinly supported.	Several main types wrong, or classes given with no visible evidence.	Classifications largely missing.
Identification Key	20 pts	A clear step-by-step key that a partner can use to classify a new galaxy correctly, covering every type in the guide.	Key works for most types but skips a step or a type.	Key is confusing, or would send a reader to the wrong type.	No key.
Entry Details	20 pts	Every entry predicts what's inside (star ages, gas, star formation) from the type, and gives distance, constellation, and an image credit.	Most entries complete; a few details missing.	Entries are mostly just a picture and a label.	Entries missing.
The Tricky One	10 pts	For an edge-on, interacting, or disputed galaxy, explains why it's hard to classify and defends a best call.	Identifies why it's tricky, but the defense is thin.	Classifies it without noticing the difficulty.	No tricky galaxy included.
Presentation	15 pts	Consistent, clean layout that reads like a real field guide; images are clear and labeled.	Mostly clear with minor inconsistencies.	Hard to use or inconsistent.	Not submitted.

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🔭 Project 5.1.3 · Unit 5 of 6 · Single Semester