Review and reference of iTelescope.net remote telescopes
Laurence
7dc6119359
The previous commit asserted that the 21 Jul Centaurus A data came back with a saturated nucleus, and booked a short-exposure core set on T32 to fix it. The assertion was wrong. It came from taking the maximum pixel inside a 300 x 300 px box centred on the frame. That measures the brightest thing near the middle of the image, which is not the same as measuring the galaxy. The 65313 ADU belonged to a foreground star 128 px (69 arcsec) from the nucleus, well inside the box. Median filtering the inner 800 x 800 px to remove stars leaves the galaxy peaking at 1944 ADU, roughly a thirtieth of the clip level, with not one star-free pixel above 30000 ADU anywhere in that box. The brightest pixel in the whole frame is at the right-hand edge, 2370 px from centre. The core looked blown in the processed image because of the stretch, not the sensor: the white point sat at the 99.995th percentile, a level set by field stars, so the galaxy's entire range from a 7 ADU sky to a 1944 ADU peak was compressed into the top few percent of the tone curve. Re-rendering the same frames with a second curve scaled to the galaxy recovered the core completely, with no new data. The T32 reservation has been cancelled without running, so it cost nothing. The other three reservations were verified intact afterwards and quota is back to 6:05 of 8:00. plans/hdrcore-t32.txt stays in the repo and on the scope: 47 Tuc and the SMC may genuinely saturate, a dense cluster core being the fastest thing there is to clip, and the ladder is ready if they do. The corrected habit is recorded in CAMPAIGN.md: measure whether a core is saturated before buying time to fix it, filtering stars out of the measurement first. The check takes a minute and would have saved this whole detour. TODO.md also records a second result that affects future planning: the faint outer halo of that stack is limited by the sky-plane subtraction, which absorbed about 17.9 ADU/px of real halo light, rather than by exposure time. More integration alone would not have gone deeper. |
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| data | ||
| docs | ||
| plans | ||
| state | ||
| .gitignore | ||
| CAMPAIGN.md | ||
| CLAUDE.md | ||
| README.md | ||
| TARGETS.md | ||
| TELESCOPES.md | ||
itelescope
Reference and review of the iTelescope.net remote telescope network: every telescope, its specs, what it is good at, and which one to book for a given target.
- TELESCOPES.md: the full review, grouped by observatory, with a "choosing a telescope" guide at the end.
- TARGETS.md: southern-sky targets invisible from the UK, matched to scopes and to the time of year to book them.
- data/itelescope-telescopes.csv: snapshot of the network's maintained specs sheet (source of truth for the numbers).
- state/: project state under the Default Workflow.
Sources: the iTelescope support article (telescope summary) and the network's maintained Google Sheet. The launchpad at go.itelescope.net is login-only.