COSESAI

Telescope Field of View Calculator — 8-inch SCT, 25mm eyepiece, deep-sky framing

Telescope Field of View Calculator: Why a 25mm Eyepiece Doesn’t Always Show Andromeda

By xiezixing 2026年7月10日

True field of view, exit pupil, and Dawes limit determine what you actually see through any telescope — and the wrong eyepiece math can hide Andromeda in plain sight.

Security Headers Checker — 12-Header Audit, A+ to F Grade

未分类

Security Headers Checker: A+ to F Grade in 30 Seconds

By xiezixing 2026年7月9日

Audit HTTP response headers for OWASP security compliance. Paste raw headers from curl, DevTools, or CI — get a letter grade with copy-ready fixes for HSTS, CSP, X-Content-Type-Options, COOP/COEP/CORP, and nine more.

Title Case Converter — AP, Chicago, Wikipedia style rules

未分类

Title Case Converter: When ‘The’ Stays Lowercase

By xiezixing 2026年7月9日

Editorial title casing is not a single transformation — it's a style decision. AP, Chicago, and Wikipedia each draw the function-word line differently.

未分类

Reading the Genetic Code in All Six Frames

By xiezixing 2026年7月9日

A walkthrough of how six-frame translation, codon degeneracy, and stop-codon detection turn a raw DNA string into the protein you are actually looking for.

Bcrypt Generator - Why Your Password Hash Is the Wrong Defense

未分类

Why Your Password Hash Is the Wrong Defense (and How Bcrypt Closes the Gap)

By xiezixing 2026年7月9日

Bcrypt has held the password-storage line for twenty-five years. Here is the algorithm, the cost knob, and the four things that fail when teams wire it in.

CSV Transformer — six declarative operations that replace most ad-hoc pandas scripts

未分类

Six Operations That Replace Most of Your Ad-Hoc pandas Scripts

By xiezixing 2026年7月9日

The CSV Transformer at elysiatools.com — six declarative operations (rename, add_column, remove_column, convert_type, calculate, filter_values) that turn messy CSV cleanup into a JSON file the next person can read.

Poker Outs and Equity Simulator poster - why 8 clean outs beat 31 dirty outs

未分类

Why 8 Clean Outs Beat 31 Dirty Outs (Poker Equity vs Rule of 4 and 2)

By xiezixing 2026年7月9日

The Rule of 4 and 2 is right — it just hides the dirty-outs problem. 17 clean outs vs 6 dirty on Ah Kh / Qh Jh 2c, with 60% equity vs the textbook 36%.

Frequency Wavelength Converter poster for elysiatools.com/en/tools/frequency-wavelength

未分类

Why 1 kHz Is 0.343 m in Air and 5.96 m in Steel: The Frequency–Wavelength Trap

By xiezixing 2026年7月8日

A 1 kHz signal is not the same length in every medium. The wave equation v = f · λ plus four medium presets (air, water, steel, light) decide everything from antenna length to sonar resolution — and a free browser converter handles the math in under a second.

PDF Anonymizer Report - auto-redact PII from PDFs for GDPR compliance

未分类

Three Regexes Catch 95% of PDF PII — And the Two That Always Slip Through

By xiezixing 2026年7月8日

The default pattern set leaves your team compliant on the day you enable it and exposed the day you forget a field. Here is the two-pass review workflow that survives a real audit.

Accessibility Heatmap Generator — Poster

未分类

Where Your Contrast Checks Stop at 4.5:1 and the Heatmap Keeps Going

By xiezixing 2026年7月8日

A spatial WCAG audit replaces per-pair ratio checks with one overlaid view of every failing region — including the gradient failures no eyeball test catches.