SkyTarget — Smart-Telescope Deep-Sky Catalog
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SkyTarget — Smart-Telescope Deep-Sky Target Catalog

The raw object fields — coordinates, magnitude, size, type — are commodity; OpenNGC ships them free. The defensible value is the derived observing layer: a deterministic, gear-specific “what should I observe & image tonight with my scope” surface — difficulty tier, best observing month and season, peak transit altitude for your latitude, recommended aperture and exposure class, a smart-telescope-friendly flag, and a per-instrument field-of-view fit grid. It is exactly the “best targets tonight” experience that ZWO Seestar, Vaonis Vespera, Unistellar, Celestron Origin and SkySafari expose in-app — and exactly what a hobbyist will pay for as a curated seasonal pack.

Preview-only page. It shows the structure and capability of this catalog using a small, representative sample. The best observing month / season, the peak transit altitude, the exposure class & recommended aperture, and the per-scope FOV-fit framing — the derived, sellable observing layer — are withheld here, and the full catalog is not downloadable from this page. It is provided separately after licensing.

Coverage & headline figures

A clean OpenNGC backbone (NGC/IC + Messier/Caldwell/Barnard) plus a deterministic, gear-specific observing layer and a per-instrument FOV-fit grid. Every derived field is a documented first-order formula — no LLM, reproducible, public-source.

14,033
Deep-sky objects
full OpenNGC ingest
12,159
Imageable objects
extended, photographable targets
2,921
Smart-telescope-friendly
single-frame, mag ≤ 13
7
Smart-telescope profiles
Seestar, Vespera, eVscope, Origin…
84,434
Object × scope FOV-fit cells
6,171 “recommended” framings
110
Messier objects
across 89 constellations

Type mix (imageable): Galaxy 10,521 · Open cluster 663 · Galaxy pair 231 · Globular cluster 208 · Planetary nebula 130 · Nebula 94 · HII region 83. Difficulty distribution: 90 trivial · 300 easy · 509 moderate · 2,094 challenging · 8,464 difficult. Quality: 12,155 / 14,033 (87%) objects clear the 0.5 client-grade completeness bar.

Source & attribution (public, open-license)

  • OpenNGC by Mattia Verga (github.com/mattiaverga/OpenNGC) → the object backbone — NGC.csv + addendum.csv, CC-BY-SA-4.0. Attribution carried in every export and pack.
  • Derived observing layer → deterministic transit, season, difficulty, exposure and FOV-fit formulas computed on top of OpenNGC (the proprietary value).
  • SIMBAD / VizieR TAP → wired as optional enrichment / QA hooks (disabled in v1; OpenNGC alone supplies every promised raw field).

What’s in it — schema

Five linked tables. objects is the headline deliverable — one canonical row per object, raw OpenNGC fields plus the derived observing layer; object_scope_fit is the per-instrument framing product computed against each smart scope.

Tables in the dataset
Table Grain (one row =) Notable columns Rows
objects one canonical deep-sky object type, mag, size, difficulty_tier, best_month, smartscope_friendly 14,033
object_scope_fit one object × one scope fov_fit_ratio, framing (well_framed / tight / too_large) 84,434
constellations one constellation rollup object counts, dominant season, brightest object 89
scope_profiles one smart-telescope model aperture_mm, focal_length_mm, fov_width/height_deg 7
object_types one object-type code type_label, imageable, per-type count 21

Columns in objects (the headline table)

name / catalog Primary designation (NGC / IC / Mel…)
messier / common_names Messier number + popular names
type_label Galaxy / nebula / cluster / …
constellation IAU constellation
ra / dec J2000 coordinates
v_mag / b_mag / surf_br Magnitude & surface brightness
maj_ax / min_ax (arcmin) Apparent angular size
difficulty_tier trivial … difficult, brightness-bucketed — gated
best_month / season When it transits near local midnight — gated
peak_altitude_deg Meridian transit altitude for your latitude — gated
recommended_aperture Aperture class (binoculars → 250mm+) — gated
exposure_class short / moderate / long integration — gated
smartscope_friendly Single-frame smart-scope target flag — gated
quality_score 0–1 completeness score — gated

Columns in object_scope_fit (per-instrument framing)

object_id / scope_key Cross-link to object & scope profile
scope_fov_deg That instrument’s field of view
fov_fit_ratio Object size vs. scope short-axis FOV — gated
framing too_small / well_framed / tight / too_large — gated

Sample preview gated

A representative slice of showpiece Messier targets — the kind of “observe tonight” list the derived layer powers. The commodity OpenNGC fields (type, constellation, magnitude) are shown; the best observing month, the peak transit altitude, and the smart-scope FOV fit — the proprietary, sellable derived columns — are redacted. Eight of 14,033 objects; ordering does not reflect any score.

objects — 8 sample rows (best month, transit altitude & FOV fit withheld)
Object Common name Type Const Mag (V) Best month Peak alt @40°N Smart-scope fit
M31 / NGC0224 Andromeda Galaxy Galaxy And 3.4 •••• ••.•° ••••
M45 / Mel022 Pleiades Open cluster Tau 1.2 •••• ••.•° ••••
M42 / NGC1976 Great Orion Nebula Cluster + nebula Ori 4.0 •••• ••.•° ••••
M13 / NGC6205 Hercules Globular Cluster Globular cluster Her 5.8 •••• ••.•° ••••
M8 / NGC6523 Lagoon Nebula Nebula Sgr 5.8 •••• ••.•° ••••
M81 / NGC3031 Bode’s Galaxy Galaxy UMa 6.9 •••• ••.•° ••••
M27 / NGC6853 Dumbbell Nebula Planetary nebula Vul 7.4 •••• ••.•° ••••
M51 / NGC5194 Whirlpool Galaxy Galaxy CVn 8.4 •••• ••.•° ••••

Request the full live sample

Get a live, end-to-end sample of SkyTarget — the objects catalog with the full derived observing layer (best month/season, transit altitude for your latitude, difficulty, aperture & exposure class), the per-scope FOV-fit grid, and the ready-to-sell seasonal target packs.

Request the full live sample →

No full dataset is downloadable from this page. Object data from OpenNGC (Mattia Verga), CC-BY-SA-4.0; derived observing layer © SkyTarget.