Session Checklist
Start of night and end of night, for the rig you actually run — a tripod carried out to the patio or a pier under a dome, on your first rig and every one after it. Set what the rig has; the list drops what doesn’t apply and adds what does. End of night is not an afterthought: flats, the shutter and the backup are where a good night gets lost.
No item invents a figure. Where one needs a cooling rate, a flip limit or a heater setting, it either links the page the figure came from or tells you whose figure to use. Practice the community argues about is marked contested, with both sides.
Open it before you lose signal: once loaded, ticking, the rig toggles and red mode all work with no connection. A reload needs the network. Or print it — the printout is plain black on white with empty boxes.
Your rigPortable · uncooled camera · no guider · laptop · mains powerChangeDone
The rig is saved in this page’s address. Bookmark it, or send it to someone with the same setup; it reopens with the same list.
Start of night0 of 23 done
Before dark
0 of 6Decisions that are cheap in daylight and expensive at midnight.
- Prevents: Cloud loss
- Prevents: Gradients
- For: PortablePrevents: Bloated soft stars
Setup and power
0 of 8Everything that rides on the mount, attached, balanced and connected.
- For: Portable
- Prevents: Trailing in part of exposure
- For: Mains power
- For: Laptop
- Prevents: Worse after meridian flip
Alignment
0 of 2Polar axis, pointing and framing.
- For: PortablePrevents: Field rotation
Focus
0 of 3Measured, not judged by eye, and re-checked as the night cools.
- For: Manual focuserPrevents: Bloated soft stars
- For: Manual focuserPrevents: Bloated soft stars
- Prevents: Triangular corner stars
Sequence
0 of 4What runs unattended, and what stops it safely.
- Prevents: Walking noise
- For: No guiderPrevents: Walking noise
End of night0 of 14 done
Shutdown and park
0 of 2Stop, park, and close up against the weather first.
Flats
0 of 4Before anything in the train moves: focus and rotation exactly as the lights had them.
- Prevents: Flats made it worse
- Prevents: Flats made it worseAstrocamp, “How to calculate the correct ADU target for flats”AstroWorldCreations, “Understanding flats, part 3”
- Prevents: Banding
- ContestedPrevents: Flats made it worseAAVSO, “Bias frames and CMOS cameras”
Bias versus dark flats on CMOS is argued both ways. Testing reported by AAVSO found short CMOS darks carry structure bias frames miss, which is why we default to dark flats. Many imagers calibrate flats with bias on sensors whose short exposures are clean, without trouble. Compare a bias with a dark flat from your own camera; the answer is per sensor.
Cooling down
0 of 1Camera back toward ambient, then power off in order.
Covering and closing
0 of 3Caps, covers, and the observatory or the car left in a known state.
- UnverifiedFor: Portable
Widely given advice; we have not located a manufacturer source for it.
- For: Portable
Data backup
0 of 4A second copy exists and is checked before any card is wiped.
How this is computed
shown(item) = item has no conditions
or any one of its conditions matches your rig
matches(cond) = every toggle the condition names equals yoursEach item is one row of data: the phase it belongs to, the action, one line of why, the rig conditions that include it, and where relevant the Failure Atlas mode it prevents. “For:” under an item names the condition that put it on your list. Items with no condition are on every rig’s list.
End of night runs park, then flats, then cooling down. Flats have to be taken before focus or rotation moves, and dark flats want the flats’ sensor temperature — warming the camera first changes it.
A figure appears only with its source linked beside it; the data tests fail any item that states a number without one. Two items carry claims we could not source and are marked unverified rather than dropped or dressed up. Camera warm-up before power-off is shown only as your manufacturer’s instruction: QHY’s manual asks for it, the ZWO manuals we checked do not, and neither gives a rate.
Source: docs/06-lifecycle.md § 5 (Act 5, Session Checklists) · docs/10-failure-atlas.md for the failure each item prevents · per-item sources linked beside the item. Content in packages/data/src/session/checklist.ts; the filtering is unit-tested across all 9,216 rig combinations.