These are the best Pentax lenses for astrophotography when you want low coma, clean corners, and weather-ready handling for Milky Way landscapes, star trails, and tele-nightscapes—across APS-C and full-frame K-mount bodies. Full-frame shooters should anchor with the HD PENTAX-D FA 15–30mm f/2.8 ED SDM WR, a bright, tank-tough ultra-wide with strong sagittal control and crisp micro-contrast for blue hour to deep night; add the HD PENTAX-D FA 21mm f/2.4 Limited DC WR for a compact, sealed wide that renders foreground texture beautifully and stays fast enough for tracked or high-ISO work. Prime-driven extremes shine with third-party glass: the IRIX 15mm f/2.4 (K-mount) offers a long, precise focus throw, low coma, and rear filter slot for gels; the IRIX 11mm f/4 pushes sweeping skies with disciplined geometry; and the Laowa 12mm f/2.8 Zero-D (K) brings rectilinear discipline in tight spaces with strong corner hold at f/2.8–f/3.2. Budget-friendly classics still deliver: the Samyang 14mm f/2.8 (K) is a workhorse for wide galactic cores, while the Samyang 24mm f/1.4 (adapted to K) gives blazing speed for tracked panos and night timelapse. For tele-nightscapes and compressed constellations, the Samyang 135mm f/2 ED (K) is a cult favorite—razor sharp wide open with smooth, long-throw manual focus that makes star pulls precise—and pairs well with star trackers for nebula fields. On APS-C, the HD PENTAX-DA★ 11–18mm f/2.8 ED DC AW is the pro ultra-wide—fast, sealed, corner-clean—and the smc/HD PENTAX-DA 12–24mm f/4 provides rectilinear flexibility for city nights and aurora; tiny Limited primes round out lightweight kits: the HD PENTAX-DA 15mm f/4 Limited (famed sunstars, great flare control for moonlit scenes) and HD PENTAX-DA 21mm f/3.2 Limited (close-focus intimacy for foregrounds) reward careful exposure and, with Astrotracer, punch above their apertures. For night portraits and environmental astro, the HD PENTAX-D FA★ 50mm f/1.4 and HD PENTAX-D FA★ 85mm f/1.4 bring flagship sharpness and creamy roll-off for “stars + subject” frames, while the HD PENTAX-D FA 100mm f/2.8 Macro WR doubles as a tele for compressed star fields and moonlit textures. Across the lineup, Pentax body strengths are a force multiplier: in-body Shake Reduction stabilizes composition while you frame, Astrotracer turns wide primes into pinpoint-star tools without a tracker, Pixel Shift can record ultra-clean foregrounds for blends, electronic level and live-view peaking aid exact infinity, and WR/AW builds keep you shooting through frost, wind, and sea spray. Practical picks: choose D FA 15–30/2.8 for FF ultra-wide speed, D FA 21/2.4 Limited for compact, sealed wide scenes, IRIX 15/2.4 or Laowa 12/2.8 for prime-driven extremes, and Samyang 135/2 for tele-nightscape artistry; on APS-C, run DA★ 11–18/2.8 as the fast, sealed cornerstone, add DA 12–24/4 for rectilinear coverage, and pocket DA 15 Limited or DA 21 Limited for ultralight nights. Field tips: focus with 10× live view on a bright star, use the “500-rule” (FF) or “300-rule” (APS-C) to cap shutter before trailing, shoot wide open or stop down 1/3–2/3 stop if corner aberrations appear, disable SR on a locked tripod, enable Astrotracer for longer subs, build foreground/star blends with a lower-ISO foreground frame, and carry a soft heater or hand warmer to fight dew. Whether you’re mapping the galactic core over sea stacks, tracing aurora curtains, or framing tight constellations against mountain silhouettes, the best Pentax lenses for astrophotography combine fast, coma-tamed optics with rugged sealing and Pentax’s in-body tools—so your night skies print big, sharp, and full of color.