Brand

•  Askar (28)
•  Sky-Watcher (22)
•  Takahashi (1)
•  TEC (11)
•  TS Optics (18)
•  William Optics (25)
•  ZWO (4)

Price

• €320.00 - €74,000.00

Aperture (mm)

•  51 (2)
•  56 (1)
•  60 (2)
•  61 (2)
•  62 (1)
•  68 (1)
•  70 (2)
•  71 (2)
•  72 (1)
•  76 (1)
•  80 (4)
•  81 (2)
•  82 (1)
•  90 (1)
•  91 (4)
•  100 (4)
•  108 (1)
•  110 (1)
•  111 (1)
•  120 (7)
•  131 (2)
•  132 (2)
•  150 (5)
•  156 (1)
•  181 (1)

Camera thread

•  M48×0.75 (3)
•  M54 × 0.75 female (1)

Filter thread

•  M48 × 0.75 (2-inch) (4)
•  M48×0.75 inside final adapter (5)
•  M48×0.75, 2-inch (5)

Focal length (mm)

•  178 (1)
•  230 (1)
•  250 (1)
•  260 (1)
•  269 (1)
•  300 (1)
•  355 (1)
•  360 (2)
•  365 (1)
•  400 (3)
•  419 (1)
•  420 (1)
•  448 (3)
•  478 (1)
•  490 (2)
•  518 (1)
•  528 (1)
•  530 (1)
•  540 (1)
•  550 (2)
•  559 (1)
•  600 (2)
•  609 (1)
•  648 (1)
•  700 (1)
•  766 (1)
•  780 (3)
•  840 (2)
•  900 (3)
•  910 (2)
•  983 (1)
•  998 (1)
•  1050 (2)
•  1200 (3)
•  1217 (1)

Focal ratio

•  3.2 (1)
•  3.5 (1)
•  3.8 (1)
•  4.8 (4)
•  4.9 (6)
•  5.5 (1)
•  5.6 (1)
•  5.9 (2)
•  6.5 (3)
•  6.8 (1)
•  6.9 (3)
•  7 (2)
•  7.0 (3)
•  7.5 (1)
•  7.8 (1)
•  8.8 (1)
•  9.6 (1)
•  11 (2)
•  f/3.8 (1)
•  f/4.5 (1)
•  f/4.6 (1)
•  f/4.8 (2)
•  f/5 (3)
•  f/5.5 (2)
•  f/5.6 (3)
•  f/5.8 (2)
•  f/5.9 (3)
•  f/6 (6)
•  f/6.4 (1)
•  f/6.5 (2)
•  f/6.7 (1)
•  f/6.8 (2)
•  f/6.9 (2)
•  f/6.45 (2)
•  f/6.78 (1)
•  f/7 (21)
•  f/7.5 (6)
•  f/7.7 (1)
•  f/7.8 (1)
•  f/8 (4)
•  f/9 (1)
•  F5.5 (objective lens) F4.5 (plus the reducer) (1)
•  F5.6 (1)

Image circle (mm)

•  43 (4)
•  43.2 (1)
•  44 (5)
•  45 (6)
•  46 (1)
•  48 (2)
•  50 (2)
•  55 (3)
•  60 (2)

Optical design

•  4-element Petzval (2)
•  5-element Petzval (6)
•  6-element Petzval (1)
•  7-element astrograph (3)
•  Air-spaced ED doublet apochromatic refractor (2)
•  Air-spaced fluorite doublet (3)
•  Air-spaced fluorite triplet (1)
•  Air-spaced triplet apochromatic refractor (4)
•  Doublet (including one ED glass) (1)
•  Doublet apochromat (2)
•  ED doublet apochromatic refractor (8)
•  ED doublet refractor (1)
•  Five-element Advanced Petzval; two Super ED, one ED, one lanthanum and one X element (1)
•  Fluorite apochromat, 2 elements in 2 groups (1)
•  Four-element air-spaced apochromat; one ED element (4)
•  Oil-spaced fluorite triplet (4)
•  Quadruplet air-spaced APO (including two ED glass) (4)
•  Quadruplet air-spaced APO(including one ED glass) (5)
•  Quadruplet petzval APO（including one piece of SD glass） (1)
•  Quintuplet air-spaced APO (including two ED glass) (1)
•  Quintuplet air-spaced APO (including two ED glasses) (1)
•  Quintuplet dual ED air-spaced APO (2)
•  Quintuplet flat-field APO (including two ED elements) (1)
•  Quintuplet fully air-spaced Petzval APO (including one ED glass) (1)
•  Quintuplet petzval APO（including two pieces of SD glass） (1)
•  Quintuplet petzval APO（One piece of SD glass, one piece of ED glass） (1)
•  Seven-element EVO Petzval; three Super ED elements (1)
•  Sextuplet petzval APO (includes 2 pieces of SD glass ) (1)
•  sextuplet with two ED glasses air-spaced APO (1)
•  Three-element ED apochromatic refractor (6)
•  Triplet air-spaced APO (including one ED glass) (6)
•  Triplet apochromat (7)
•  Triplet apochromat with 2 ED elements (1)
•  Triplet apochromatic refractor (2)
•  Triplet dual ED air-spaced APO (objective lens) Sextuplet refractor for full-frame astro photography (with reducer) (1)
•  Two-element air-spaced ED apochromatic refractor (1)