World Cyanotype Day falls on the last Saturday of September every year, and this year The Big Camera is marking it on the plaza at Ijams Park with a free community workshop from noon to three. Cyanotype is a printing process from the earliest days of photography: you lay an object — a fern, a feather, a set of keys — on fabric treated with a light-sensitive solution, leave it in the sun, and rinse it in water. What comes out is a white silhouette on Prussian blue.

★Why it belongs in a park

The process was popularized by Anna Atkins, who in the 1840s used it to make what is considered the first book illustrated with photographs — a catalog of British algae, pressed straight onto the treated sheets. Doing it at Ijams Park means the subjects are on the ground around you. Bring nothing; pick up a leaf on the walk in from the lot. Saturday's forecast is full sun, which is the whole method.

It is free, but the park asks you to reserve a ticket at no charge so they can plan the fabric. It runs alongside the stained-glass workshop and the possum meet-and-greet, so a Saturday at the park can be built entirely out of things you make or meet.

Puckers keeps weekend brunch on the menu from nine to two on Saturday and Sunday, and this Saturday the clock does something useful: Tennessee and No. 1 Texas kick off at noon at Neyland, on ABC, so the second half of brunch is the first half of the game. It is the first time the two schools have met on either campus, and ESPN's College GameDay is setting up on the hill in the morning. If you are not among the hundred thousand walking to the stadium, a table on Mimosa Avenue with a plate in front of you is a reasonable alternative.

★How the morning works

Get there for the nine o'clock open or soon after; a noon kickoff for a game this size fills a sports bar early, and the brunch dishes carried over from the room's Mimosas days are the reason people come. Parking is the garage behind the building. Sunday is quieter — the Titans are away at the Giants at one — and brunch runs the same hours.

Kern's has put a price on a thing people have been improvising on its lawn all season: a private tailgate. The Ultimate Tailgate package is $300 a game for one-third of the Lawn Patio — a television, two couches, two cocktail tables, a canopy and a sign with your group's name on it, roped off for up to twenty people. It is offered only for Tennessee football games, and Saturday's is Texas at noon.

★The rooftop version

The bigger option is the Fan Zone: the UpTop rooftop patio for up to 75, at $2,500, with tables, stanchions and signage. Both packages take catering and beverage add-ons, and drink tickets work at Peter's Market Bar downstairs or the UpTop bar. Everything runs through an inquiry form on the Kern's site rather than a checkout, so for this Saturday the sensible move is to ask today.

For everyone else, the food hall is open eight in the morning to eleven at night on Saturday, and the game will be on whatever screens the bars have. The lawn sections are the only part that comes with a reservation.

Ijams Park has a new animal ambassador, and it is an opossum. Saturday at three is the first public meet-and-greet: an hour that starts with the animal and the naturalist who handles it, covers what the park calls the misunderstood marsupial's adaptations — the prehensile tail, the playing dead, the tick-eating — and ends with a short introduction to nature journaling and an opossum drawing every participant makes and takes home.

★Who it's for

The program is built for ages five and up, and it is mostly sitting, which makes it the easiest thing on the park's Saturday for the youngest visitors. It also caps a full day there for a family: the free storytime at the Nature Playscape runs ten to noon, and World Cyanotype Day, a free sun-print workshop on the Visitor Center plaza, runs noon to three — both covered in this episode. Ten dollars, register ahead, and parking is free for anyone signed up. The next one is a Wednesday evening in late October if Saturday fills.

Every Saturday from ten to noon, someone reads a book out loud in the woods at the Nature Playscape by Mead's Quarry, and it costs nothing. This week's theme is space, the book is "Moon! Earth's Best Friend," and the scheduling is either luck or somebody at the park paying attention: the Harvest Moon turns full at 12:49 that afternoon and rises over the river at 7:18 that night. A kid who hears the book in the morning can see the subject after dinner.

The format is loose. Some weeks there is a hands-on activity; some weeks the reading is the activity and the rest is roaming the Playscape. Bring a blanket or a chair and a snack. Parking at the quarry lot is $5 a car unless you are a member, and the walk in is short. Saturday is sunny and in the low 70s by noon, which after the month we have had counts as news.

Ijams After Dark has been walking people out to Mead's Quarry after sunset all summer to watch bats work the lake, and Thursday is the last date on the calendar. A naturalist teaches you to tell species apart by how they fly, and the park sets up blacklight stations along the way so the insects and everything else drawn to ultraviolet turn up too. It runs eight to nine-thirty, ages ten and up, fifteen dollars.

★The weather is the question

Thursday is the one wet day of the week. The forecast has rain showers likely through the afternoon, a fifty percent chance before eight, and partly cloudy after — which is to say the walk is on the right side of the front, barely. Check the event page before you leave the house, wear shoes for wet rock, and bring a headlamp with a red setting if you own one. The upside is what a front does to the air: Thursday night's low is 59, the first night under 60 since spring.

The last day Knoxville's airport recorded a high in the 70s was June 23. Since then, every single day has topped 80, most of them 90 or better, and the last three weeks have run 86 to 98. That ends Thursday, when a front comes through with rain, and what follows is the weekend South Knoxville has been waiting on since spring: Friday 77 and mostly sunny, Saturday 77 and sunny, Sunday 78, with nights in the low 50s.

★What that does to the trails

The Urban Wilderness is more than a thousand forested acres along the south bank with over sixty miles of trail and greenway, anchored by Ijams Park, Baker Creek Preserve, the River Bluff Natural Area and the Forks of the River. For three months the only usable hours have been the first two after sunrise. This weekend the whole day is usable — a nine o'clock start at Baker Creek in the low 60s, or a four o'clock loop with the sun still up until 7:26.

Two notes for the first cool weekend. The trails will be busy, especially the Baker Creek flow trails and the Mead's Quarry loops, and the Saturday noon kickoff empties them for three hours in the middle of the day if you want them to yourself. And Thursday's rain means Friday morning is the muddy window; by Saturday the surface will have set up. Every trailhead in the district is free.

Renew in Nature is a two-hour Sunday morning at the Ijams Park homesite built in three movements: an outdoor yoga flow to start, a sound bath in the middle, and a forest bathing session — a slow, guided, mostly silent walk in the trees — to close. The park's pitch is the stacked benefit of all three, and the pitch is easier to buy on a 65-degree morning than on the 90-degree ones it has been offering yoga in all summer.

Forty dollars a person, pre-registration required. Bring a mat; a journal for the walk and a pillow or eye mask for the sound bath are optional. It ends at noon, which is exactly when the DJs start at Mead's Quarry a mile down the road, so Sunday at the park can go from silence to a dance floor without leaving the property.

The fall run of the beginner fungi workshop continues Sunday at three: an Ijams Park naturalist, a mile and a half of trail, and the basics of what a mushroom actually is — the parts, the names, how a fungus differs from a lichen, and what each is doing for the forest. No prior knowledge assumed, ages fourteen and up, fifteen dollars.

The timing this week is good. Thursday brings the first real rain in a while, then three dry days in the 70s, which is roughly the recipe for a fall flush. Wear shoes you can take off the path, bring something to write on, and register ahead; parking is free for anyone signed up. If Sunday fills, the next dates are October 18 and Halloween morning.

The park's fall wildflower walk runs twice this week — Thursday at 5:30 in the evening and Sunday at three in the afternoon — and the pitch is that the late-September woods are as much a flower show as April, just in purple and yellow instead of white. An Ijams Park naturalist leads a mile and a half through the ironweed and goldenrod and explains what each is doing for the pollinators that are still out.

Of the two dates, Sunday is the sure one: mostly sunny and 78. Thursday evening has a fifty percent chance of showers, so if you book that one, check the event page in the afternoon. Fifteen dollars, ages fourteen and up, parking free for participants. The same walk runs again October 3 and October 17.

Visualize Art Studio runs a two-hour version of a stained-glass class out of a mobile workshop, and Saturday it parks at Ijams Park. You start with a kit of glass already cut and ground into a design — a cowboy boot, a hummingbird or a lotus — pick the colors, and learn the two skills that actually make a panel: wrapping each piece in copper foil and soldering the seams. Two hours later you leave with a finished piece.

Eighty dollars covers the kit, the tools and the instructor. Fourteen and up, with anyone under eighteen accompanied by an adult. Wear cotton, closed shoes, and tie long hair back — there is a hot iron involved. It runs eleven to one, which means you can finish, walk out to the plaza, and be at the free cyanotype table by one-thirty.

Dizzy teaches hooping on Thursday evenings in the Miller Education Building at Ijams Park, and the method is the one good movement teachers use: take a trick, break it into its parts, drill the parts, put it back together. Classes go at the pace of whoever shows up. It is an adult class, twenty-five dollars a session, and there are hoops to borrow if you don't own one.

Thursday is the wet day of the week, and this is the one thing on the park's Thursday that is indoors. Six to seven; the Miller Building is on Island Home Avenue, and the event page has directions.

Earl's, down on Waterfront Drive by Suttree Landing, runs a different deal every day of the week from open to close, and the week's board is above. The Saturday game-day column is the same one that has run all season — two dollars off drafts and pizza, six-dollar Orange Bliss, beer buckets six for the price of five — but this is the first home game with a noon kickoff, so for once the board opens at eleven with an hour to spare and covers lunch instead of dinner.

The river-facing tables are the ones to want on a 77-degree Saturday. Sunday is mimosas and Bloody Marys, and the Titans are away at one if the screens are on.