Glass Match

TrueField Scope Desk is a hands-on optical-train and true-field planning studio for amateur astronomers, star-party hosts, and new Dobsonian or SCT owners who want every night’s glass choice decided before the car is packed. Lock an optical tube, stock an eyepiece drawer, and watch magnification, true field of view, and exit pupil update live. Frame real solar-system disks and Messier targets on a circular field-stop canvas, stack Barlow or reducer chains, compare two eyepieces side-by-side, then export a printable session field card you can take to the mount. Build your OTA shelf Enter aperture, focal length, focal ratio, central obstruction, and mount style. Start from 12 seeded tubes—including an 8" f/6 Dob, 8" SCT, 80 mm APO, 6" Newtonian, and short-tube rich-field rigs—then duplicate or edit any setup to match the glass you actually own. Stock a real eyepiece drawer Add focal length, apparent field, barrel size, and eye relief. Twenty-four seeded Plössl, orthoscopic, wide-field, and planetary eyepieces ship ready to favorite, filter by barrel, or clone into custom glass. Live optical bench Magnification, true FOV, exit pupil, maximum useful magnification, and Dawes/Rayleigh resolution references recalculate the instant numbers change. Results are presented as educational geometry and planning aids—not observing guarantees. Barlow and reducer chains Stack ×2, ×2.5, ×3, 0.8×, or 0.63× elements on the active train. An effective-focal-length badge and before/after FOV rings show exactly how the path shifts. Target atlas and FOV theater Seeded solar-system disks and Messier DSOs include angular sizes. Tap a target to overlay margin rings on the field-stop canvas and see whether an eyepiece frames, clips, or swims around the object. Pinch-zoom field stops, constellation-line chrome, and layered nebula washes keep framing spatial instead of spreadsheet-flat. Side-by-side eyepiece compare Dual FOV circles, exit-pupil bars, magnification delta, and a one-tap “winner for this target” highlight based on framing fit make glass choices obvious. Session field cards Lock one OTA, three to five eyepieces, ordered targets, and free-text setup notes. Export a multi-page PDF with PDFKit to Files or the share sheet for clipboard use under the stars. Planning coaching and dark-sky comfort Charts-driven exit-pupil versus sky-brightness curves (bright suburb vs. darker site bands) help keep pupils in comfortable ranges—as a planning reference only. Toggle metric or imperial units, enable a night-red observatory theme for dark adaptation, and open an in-app glossary of FOV, exit pupil, and resolution terms with worked examples. Turn aperture, focal length, and eyepiece specs into a visual true-field match against real target sizes, then walk out with a clear PDF session card—rich reference math and seed catalogs, zero fluff. Intentional geometry, not guesswork at the mount.