These nebulae are formed during the last stages of a star's life when a red giant star casts of its outer layers in a process which leads to the star becoming a white dwarf. The shell of gas expands outwards and is visible for a few thousand years. The remnant of the star that is left is an intensely hot white dwarf with a surface temperature as high as 100 000K.
This is a list of the one hundred brightest planetary nebulae:
1 2 3 4 5 6 7 8 9 10 11 NGC/IC Common Equatorial Galactic Neb Star Angular Distance Con Number Name Coordinates Coordinates Mag. Mag. Size (ly) RA (2000) Dec l° b° (") [1] [2] [3] NGC 40 00 13.0 +72 31 120.0 +9.9 10.5 11.6 36 -- 4600 -- Cep NGC 246 00 47.1 -11 52 118.9 -74.7 8.5 12.0 225 -- -- 1600 Cet NGC 650/1 Little Dumbbell (M76) 01 42.3 +51 35 130.9 -10.5 11.0 16.3 120 -- 2100 -- Per IC 289 03 10.3 +61 19 138.8 +2.8 13.0 15.9 40 -- -- -- Cas NGC 1360 03 33.2 -25 52 220.4 -53.9 9.5 11.4 380 1700 -- -- For IC 351 03 47.5 +35 03 159.1 -15.2 12.0 15.8 7 39100 14700 -- Per IC 2003 03 56.4 +33 53 161.3 -14.9 12.0 15.0 8 -- 11700 31800 Per NGC 1501 04 07.0 +60 55 144.6 +6.6 12.5 14.4 52 -- -- -- Cam NGC 1514 04 09.3 +30 47 165.5 -15.3 10.5 9.4 120 -- -- -- Tau NGC 1535 04 14.3 -12 44 206.5 -40.6 9.5 12.2 18 4900 4200 -- Eri IC 418 Spirograph nebula 05 27.5 -12 42 215.2 -24.3 10.0 10.2 12 5200 3900 -- Lep NGC 2022 05 42.1 +09 05 196.7 -10.9 11.5 15.0 20 -- 10400 -- Ori IC 2149 05 56.4 +46 06 166.2 +10.5 11.0 11.6 9 4600 7200 -- Aur IC 2165 06 21.7 -12 59 221.3 -12.4 12.0 17.9 8 8200 14000 -- CMa NGC 2346 07 09.4 -00 48 215.7 +3.6 10.5 11.5 55 -- -- 3000 Mon NGC 2371/2 07 25.6 +29 29 189.2 +19.9 11.5 14.9 50 -- 8500 -- Gem NGC 2392 Eskimo nebula 07 29.1 +20 55 197.9 +17.4 9.5 10.5 45 1800 3000 3800 Gem NGC 2438 07 41.8 -14 44 231.8 +4.1 10.5 17.7 70 -- 3200 -- Pup NGC 2440 07 41.9 -18 13 234.8 +2.4 10.5 17.7 30 8500 3200 5700 Pup NGC 2452 07 47.4 -27 20 243.4 -1.0 12.5 17.7 19 -- 15700 10500 Pup IC 2448 09 07.1 -69 57 285.8 -15.0 11.0 14.2 9 10100 9100 -- Car NGC 2792 09 12.4 -42 26 265.8 +4.1 12.5 13.8 25 10100 11400 8200 Vel NGC 2818 09 16.0 -36 38 262.0 +8.6 12.5 19.4 40 -- 8500 -- Pyx NGC 2867 09 21.4 -58 19 278.2 -5.9 9.5 16.6 15 -- 12400 6200 Car NGC 2899 09 27.1 -56 06 277.2 -3.8 12.0 15.9 90 -- 6500 -- Vel IC 2501 09 38.8 -60 06 281.0 -5.7 11.0 14.5 2 19200 -- -- Car NGC 3132 Eight Burst nebula 10 07.0 -40 26 272.1 +12.4 8.5 10.1 45 -- 2200 2100 Vel IC 2553 10 09.3 -62 37 285.5 -5.4 11.5 15.5 9 1700 13400 -- Car NGC 3195 10 09.3 -80 52 296.6 -20.0 11.5 15.3 40 -- -- -- Cha NGC 3211 10 17.8 -62 40 286.3 -4.9 11.5 18.0 16 12100 5900 9200 Car NGC 3242 Ghost of Jupiter 10 24.8 -18 39 261.1 +32.1 9.5 12.3 40 3600 3900 2900 Hya IC 2621 11 00.3 -65 15 291.6 -4.8 11.5 15.4 5 15300 8200 15500 Car NGC 3587 Owl nebula (M97) 11 14.8 +55 01 148.5 +57.1 11.0 16.0 190 -- 2200 -- UMa NGC 3699 11 28.0 -59 57 292.7 +1.3 11.0 ? 45 -- -- -- Cen NGC 3918 Blue planetary nebula 11 50.3 -57 11 294.7 +4.7 8.0 ? 16 4900 6800 5000 Cen NGC 4361 12 24.5 -18 47 294.1 +43.6 10.5 13.2 100 4900 5200 4700 Crv IC 3568 12 33.1 +82 34 123.7 +34.5 11.5 13.5 15 8200 11400 -- Cam IC 4191 13 08.8 -67 39 304.6 -4.8 11.5 16.4 14 10800 14400 -- Mus NGC 5189 13 33.5 -65 58 307.2 -3.4 10.0 14.9 140 -- 4900 4100 Mus NGC 5307 13 51.1 -51 12 312.4 +10.6 11.5 14.7 13 8500 7200 8100 Cen NGC 5315 13 54.0 -66 31 309.1 -4.4 11.5 14.4 6 -- 13700 8400 Cir IC 4406 Retina nebula 14 22.4 -44 09 319.7 +15.7 10.5 17.0 30 -- 3000 -- Lup NGC 5873 15 12.8 -38 08 331.3 +16.8 12.0 15.5 6 24500 19900 30000 Lup NGC 5882 15 16.8 -45 39 327.8 +10.1 10.0 13.4 14 6200 8800 -- Lup NGC 5979 15 47.7 -61 13 322.6 -5.3 12.0 15.3 8 -- -- -- TrA Sp-1 Fine Ring nebula 15 51.7 -51 31 329.1 +2.0 13.0 14.0 72 -- -- 4700 Nor NGC 6058 16 04.4 +40 41 64.7 +48.3 13.0 13.9 26 -- 9100 -- Her IC 4593 White Eyed Pea 16 11.7 +12 04 25.3 +40.8 11.0 11.2 12 -- 6800 -- Her NGC 6153 16 31.5 -40 15 341.9 +5.4 11.0 16.1 24 5900 6500 5400 Sco NGC 6210 16 44.5 +23 48 43.1 +37.8 9.0 12.7 16 6200 10100 5300 Her IC 4634 17 01.6 -21 50 0.4 +12.2 11.0 13.9 7 14400 16000 16000 Oph NGC 6302 Bug nebula 17 13.7 -37 06 349.5 +1.1 12.0 ? 45 330 1800 -- Sco NGC 6309 Box nebula 17 14.1 -12 55 9.7 +14.8 11.0 14.4 14 12700 10800 -- Oph NGC 6326 17 20.8 -51 45 338.2 -8.4 11.5 13.5 12 12700 15700 -- Ara NGC 6337 Red Spider nebula 17 22.3 -38 29 349.4 -1.1 12.0 14.9 48 4900 -- -- Sco NGC 6369 Little Ghost nebula 17 29.3 -23 45 2.4 +5.9 11.5 15.9 28 3000 5500 4900 Oph IC 4663 17 45.5 -44 54 346.3 -8.2 12.5 15.2 14 6500 -- -- Sco NGC 6445 17 49.3 -20 01 8.1 +3.9 12.0 19.0 33 -- 3300 7300 Sgr NGC 6543 Cat's Eye nebula 17 58.6 +66 38 96.5 +29.9 8.5 11.1 20 -- 5900 -- Dra IC 4673 18 03.3 -27 06 3.6 -2.4 13.0 17.6 16 11700 13400 -- Sgr NGC 6537 18 05.2 -19 51 10.1 +0.7 12.0 18.8 6 -- 4200 6900 Sgr NGC 6565 18 11.9 -28 11 3.5 -4.6 12.5 18.5 10 6200 5900 -- Sgr NGC 6563 18 12.0 -33 52 358.5 -7.3 12.5 18.0 45 9500 3100 -- Sgr NGC 6572 18 12.1 +06 52 34.6 +11.9 8.5 13.6 14 9500 7800 -- Oph NGC 6567 18 13.8 -19 05 11.7 -0.7 11.5 14.4 9 -- 9100 4200 Sgr IC 4699 18 18.5 -45 59 348.0 -13.9 12.5 15.1 7 20500 -- -- Tel NGC 6629 18 25.7 -23 12 9.4 -5.1 11.5 12.9 15 5900 5500 6400 Sgr NGC 6644 18 32.6 -25 08 8.4 -7.3 11.5 15.6 3 10400 21200 9800 Sgr IC 4776 18 45.8 -33 21 2.1 -13.4 11.5 14.1 7 20500 -- 24000 Sgr NGC 6720 Ring nebula (M57) 18 53.6 +33 02 63.2 +14.0 9.0 15.3 70 1500 1500 -- Lyr NGC 6741 Phantom Streak 19 02.6 -00 27 33.8 -2.7 11.0 14.7 8 2350 16300 4800 Aql NGC 6751 19 05.9 -06 00 29.2 -5.9 12.0 15.5 21 -- 8200 6400 Aql IC 4846 19 16.5 -09 03 27.6 -9.7 12.5 15.2 3 31300 24800 -- Aql IC 1297 19 17.4 -39 37 358.3 -21.6 10.5 14.2 7 -- 7800 -- CrA NGC 6781 19 18.5 +06 32 41.8 -3.0 12.0 16.8 120 -- 950 5100 Aql NGC 6790 19 22.9 +01 31 37.9 -6.3 10.5 13.5 5 18600 -- -- Aql NGC 6803 19 31.3 +10 03 46.4 -4.1 11.5 15.2 6 -- -- 5700 Aql NGC 6804 19 31.6 +09 14 45.8 -4.6 12.0 14.4 35 -- 4900 5000 Aql NGC 6818 Little Gem nebula 19 44.0 -14 09 25.9 -17.9 10.0 16.9 18 -- 8200 7300 Sgr NGC 6826 Blinking nebula 19 44.8 +50 32 83.6 +12.8 9.5 10.4 25 3900 5200 -- Cyg NGC 6842 19 55.0 +29 17 65.9 +0.6 13.0 16.0 48 -- -- -- Vul NGC 6853 Dumbbell nebula (M27) 19 59.6 +22 43 60.8 -3.7 7.5 13.9 330 910 1100 -- Vul NGC 6852 20 00.7 +01 44 42.6 -14.5 13.0 17.9 28 -- -- -- Aql NGC 6884 20 10.4 +46 28 82.1 +7.1 12.5 15.6 6 17600 12700 -- Cyg NGC 6879 20 10.4 +16 55 57.2 -8.9 13.0 14.8 5 -- 20500 -- Sge NGC 6886 20 12.7 +19 59 60.1 -7.7 12.0 15.7 8 23500 22200 -- Sge NGC 6891 20 15.1 +12 42 54.2 -12.1 11.0 12.4 12 8500 8500 -- Del IC 4997 20 20.1 +16 44 58.3 -11.0 11.5 14.4 2 23500 24500 -- Sge NGC 6905 Blue Flash nebula 20 22.4 +20 06 61.5 -9.6 11.5 15.7 45 -- -- -- Del NGC 7008 21 00.5 +54 33 93.4 +5.5 12.0 13.2 85 -- -- 2900 Cyg NGC 7009 Saturn nebula 21 04.2 -11 22 37.8 -34.6 8.0 12.8 28 3100 5200 3500 Aqr NGC 7026 21 06.3 +47 51 89.0 +0.4 12.0 14.2 12 -- 7200 -- Cyg NGC 7027 21 07.0 +42 14 84.9 -3.5 9.0 16.3 14 -- 3200 3400 Cyg NGC 7048 21 14.3 +46 17 88.8 -1.7 11.5 19.1 60 -- -- 5600 Cyg IC 5117 21 32.5 +44 36 89.9 -5.1 12.5 16.7 2 -- 19200 -- Cyg IC 5148/50 21 59.6 -39 23 2.7 -52.4 12.0 16.5 120 -- -- -- Gru IC 5217 22 23.9 +50 58 100.6 -5.4 12.0 15.5 7 19600 14700 -- Lac NGC 7293 Helix nebula 22 29.6 -20 50 36.2 -57.1 7.0 13.5 900 520 590 700 Aqr NGC 7354 22 40.3 +61 17 107.8 +2.3 12.5 16.2 20 6800 -- -- Cep NGC 7662 Blue Snowball nebula 23 25.9 +42 32 106.6 -17.6 9.0 13.2 20 5200 5500 -- And Column 1: NGC or IC catalogue number. Column 2: Common name of the planetary nebula. Column 3: Right Ascension in hours and minutes for epoch 2000. Column 4: Declination in degrees and minutes for epoch 2000. Column 5: Galactic longitude of the planetary nebula. Column 6: Galactic latitude of the planetary nebula. Column 7: Approximate visual magnitude of the planetary nebula. Column 8: Magnitude of the central star of the planetary nebula. Column 9: Maximum angular diameter of the planetary nebula in arcseconds. Column 10: Distance to the planetary nebula in light years according to the three references listed below. Column 11: Constellation the planetary nebula is in. References: [1] Zhang C, (1995), A statistical distance scale for galactic planetary nebulae, Astrophys J Suppl, 98, 659. [2] Mal'kov Yu.F, (1997), Distances and physical parameters of PNe, Astron. Zh. 74, 853. [3] Bensby T, Lundström I, (2001), The Distance Scale of Planetary Nebulae, Astron and Astrophys, 374, 599.
It is very hard to accurately measure the distance to planetary nebulae. Different techniques tend to produce wildly varying estimates. Some nearby nebulae such as the Helix nebula and the Dumbell nebula have crude parallaxes available for them, but otherwise only indirect methods can be used which are usually very inaccurate and errors are often ±50% or more.