Correct the saturated-nucleus claim and cancel the booking it justified #17

Merged
laurence merged 1 commit from correct-core-saturation into main 2026-07-21 14:51:06 +01:00
2 changed files with 44 additions and 21 deletions

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@ -80,7 +80,7 @@ actual bill, and treat any not-yet-observed scope's card rate as +/-60%.
| 749230 | T8 | 26 Jul | 21:35-23:55 | catspaw-t8.txt | ~146 (25% moon disc.) | still booked | | 749230 | T8 | 26 Jul | 21:35-23:55 | catspaw-t8.txt | ~146 (25% moon disc.) | still booked |
| 749302 | T32 | 21 Jul | 18:50-21:50 | cena-t32.txt | ~350 (x1.6 rate, 25% moon disc.) | COMPLETED, billed 160. EVENING slot: T32 has a 35 deg elevation floor and Cen A culminates ~17:10 before dark, sinking to 11 deg by the old 00:35 slot (which could never have run). Ran 18:50-21:16, finishing 34 min early (plan complete, not a fault); images landed under /images/qisback/T32/NGC5128 | | 749302 | T32 | 21 Jul | 18:50-21:50 | cena-t32.txt | ~350 (x1.6 rate, 25% moon disc.) | COMPLETED, billed 160. EVENING slot: T32 has a 35 deg elevation floor and Cen A culminates ~17:10 before dark, sinking to 11 deg by the old 00:35 slot (which could never have run). Ran 18:50-21:16, finishing 34 min early (plan complete, not a fault); images landed under /images/qisback/T32/NGC5128 |
| (id not captured) | T8 | 22 Jul | 21:45-00:45 | cra-t8.txt | ~250 | booked + MySummary-verified 2026-07-21 11:45 UTC. This is queue #2 finally placed: see the resolution note below. Runs 11:45-14:45 UTC 22 Jul | | (id not captured) | T8 | 22 Jul | 21:45-00:45 | cra-t8.txt | ~250 | booked + MySummary-verified 2026-07-21 11:45 UTC. This is queue #2 finally placed: see the resolution note below. Runs 11:45-14:45 UTC 22 Jul |
| (id not captured) | T32 | 22 Jul | 18:50-19:50 | hdrcore-t32.txt | ~25 | booked + MySummary-verified 2026-07-21 13:30 UTC. HDR core set for the 21 Jul Cen A data, whose nucleus is saturated: see the note below. Runs 08:50-09:50 UTC 22 Jul, immediately before the T8 run that night | | (id not captured) | T32 | 22 Jul | 18:50-19:50 | hdrcore-t32.txt | ~25 | **CANCELLED 2026-07-21 ~15:00 UTC, never ran, 0 points spent.** Booked to fix a saturated Cen A nucleus; the nucleus is not saturated (see the correction below). Deleted from MySummary with the other three reservations verified intact afterwards; quota back to 6:05/8:00 |
| 749314 | T33 | 21 Jul | 00:05-00:50 | ngc104-test.txt | 0 (free) | booked + grid-verified 2026-07-21 08:55 UTC. 47 Tuc first-light retry, third attempt. Runs 14:05-14:50 UTC 21 Jul. Reschedule flag again No (free scopes never rebook) | | 749314 | T33 | 21 Jul | 00:05-00:50 | ngc104-test.txt | 0 (free) | booked + grid-verified 2026-07-21 08:55 UTC. 47 Tuc first-light retry, third attempt. Runs 14:05-14:50 UTC 21 Jul. Reschedule flag again No (free scopes never rebook) |
The T33 first-light test is now on its THIRD booking (749314); the two prior free The T33 first-light test is now on its THIRD booking (749314); the two prior free
@ -103,24 +103,34 @@ Verify every booking via Edit.aspx?id= probing (sequential ids), NOT the grid.
| 5 | GRAS008 | 2026-08-08T02:35:00 | 2026-08-08T06:05:00 | 2:35 AM | 6:05 AM | smc47tuc-t8.txt | ~390 | | 5 | GRAS008 | 2026-08-08T02:35:00 | 2026-08-08T06:05:00 | 2:35 AM | 6:05 AM | smc47tuc-t8.txt | ~390 |
| 6 | GRAS032 | 2026-08-09T03:05:00 | 2026-08-09T06:05:00 | 3:05 AM | 6:05 AM | tarantula-t32.txt | ~365 | | 6 | GRAS032 | 2026-08-09T03:05:00 | 2026-08-09T06:05:00 | 3:05 AM | 6:05 AM | tarantula-t32.txt | ~365 |
| 7 | (T70, blocked: server unreachable) | night TBD before 5 Aug | ~2.5h | | | scorpius-t70.txt (in scratch, re-upload needed) | ~238 | | 7 | (T70, blocked: server unreachable) | night TBD before 5 Aug | ~2.5h | | | scorpius-t70.txt (in scratch, re-upload needed) | ~238 |
| 8 | BOOKED 2026-07-21 for 22 Jul 18:50-19:50 (see table above) | | | | | hdrcore-t32.txt | ~25 | | 8 | WITHDRAWN: booked then cancelled 2026-07-21, premise was wrong (see below) | | | | | hdrcore-t32.txt | 0 |
### Short-exposure core sets are now part of the campaign ### CORRECTION (2026-07-21): the Cen A nucleus was never saturated
The 21 Jul Cen A data came back with a saturated nucleus: a single 300 s An earlier entry here claimed the 21 Jul Cen A data came back with a saturated
luminance sub reads 65313 ADU in the core, so the deep stack is clipped there nucleus, and booked a short-exposure core set on that basis. **The claim was
and no amount of processing recovers it. plans/hdrcore-t32.txt is the fix, an wrong and the booking has been cancelled without running, at a cost of zero
exposure ladder (L 8x60s, 8x15s, 8x5s, RGB 5x30s, all BIN2 to match) that points.**
blends in under the clipped core. It costs about 25 points, roughly a sixth of
what the deep run cost, and the same trick applies to any bright target.
**Apply this to the rest of the queue.** NGC 6744 (already shot, 19 Jul) has a The 65313 ADU figure came from taking the maximum pixel inside a 300 x 300 px
bright nucleus and probably needs the same treatment; 47 Tuc and the SMC box centred on the frame. That measures the brightest thing near the middle of
(queue #5) certainly will, since a globular cluster core saturates fast. Before the image, which is not the same as measuring the galaxy: it was a foreground
each remaining bright-target run, budget an extra ~25 points and an hour of star 128 px (69 arcsec) from the nucleus, sitting inside the box. Median
reservation quota for a matching short set, and cut the ladder from the deep filtering the inner 800 x 800 px to remove stars leaves the galaxy peaking at
plan's exposure rather than guessing: shortest sub = deep sub / 60 is what was **1944 ADU**, about a thirtieth of the clip level, with **not one star-free
used here. pixel above 30000 ADU**. The core looked blown in the first processed image
because of the display stretch, whose white point was set by field stars, and
re-rendering the same data with a second tone curve scaled to the galaxy
recovered it fully.
**The habit that IS worth keeping, in corrected form:** before booking extra
time to fix a saturated core, *measure whether it is saturated* - median-filter
the inner region to remove stars first, and check where the frame's bright
pixels actually are. The check costs a minute. 47 Tuc and the SMC (queue #5)
may still genuinely saturate, a dense cluster core being the fastest thing there
is to clip, so run the same measurement on their data before assuming either
way. plans/hdrcore-t32.txt stays in the repo (and on T32) as a ready-made
ladder if one of them turns out to need it.
### Session 2026-07-21 ~08:55 UTC (booking round run early, before Cen A ran) ### Session 2026-07-21 ~08:55 UTC (booking round run early, before Cen A ran)

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@ -42,11 +42,24 @@
two prior free reservations (749228, 749229) expired unused with reschedule=No; two prior free reservations (749228, 749229) expired unused with reschedule=No;
if 749314 also fails to run, stop rebooking and either walk it in (POST if 749314 also fails to run, stop rebooking and either walk it in (POST
plan.asp per plans/README.md) or drop the free objective. plan.asp per plans/README.md) or drop the free objective.
- HDR core set on T32 runs 08:50-09:50 UTC 22 Jul (plans/hdrcore-t32.txt, ~25 - The T32 HDR core set (plans/hdrcore-t32.txt) was booked and then CANCELLED on
pts). Verify after 09:50 UTC, then download and blend it under the saturated 2026-07-21 without running: the Cen A nucleus is not saturated, the earlier
core of the 21 Jul Cen A stack. The processing pipeline for that stack lives claim having measured a foreground star. See the correction in CAMPAIGN.md.
in the user's Downloads\NGC5128\20260721\stacked\scripts folder, not in this Zero points spent. The plan file remains available on T32 if a genuinely
repo, with METHODS.md alongside it. saturated target turns up.
- The 21 Jul Cen A data has been fully processed off-repo, in the user's
Downloads\NGC5128\20260721\stacked folder: masters, plate solution (0.27
arcsec on 237 stars), an LRGB composite, a globular cluster survey (289
candidates, 62% catalogue-confirmed, density falling 10.5x outward), surface
photometry (Sersic n = 4.27, Re = 400 arcsec, total G = 6.56, which matches
the catalogued brightness and so validates the photometric chain), and a
transient/moving-object search (both null, with measured limits). METHODS.md
there documents the lot. Nothing from that analysis needs to come back into
this repo, but two results affect FUTURE sessions and are recorded here:
**(a)** measure saturation properly before buying short subs, and **(b)** the
faint outer halo in that stack is limited by the sky-plane subtraction
(-17.9 ADU/px of real halo light absorbed), not by exposure time, so more
integration alone would not have gone deeper.
- CrA on T8 runs 11:45-14:45 UTC 22 Jul. Verify after 14:45 UTC: images under - CrA on T8 runs 11:45-14:45 UTC 22 Jul. Verify after 14:45 UTC: images under
/images/qisback/T8/ on t8.itelescope.net:8008, then the actual bill from /images/qisback/T8/ on t8.itelescope.net:8008, then the actual bill from
account/history.aspx into the ledger. This is the first T8 bill, so it also account/history.aspx into the ledger. This is the first T8 bill, so it also