| RASC Deep-Sky Challenge Objects © by Alan Dyer and Alister Ling | ||||||||||
| For those who wish to venture beyond the NGC, here is a selection of 45 "challenge" | ||||||||||
| targets. Most will require a 25 to 45-cm (10 to 18") telescope. However, for detecting | ||||||||||
| challenge objects, the quality of the sky, quality of the optics, use of an appropriate | ||||||||||
| filter, and the observer's experience are often more important than sheer aperture. Don't | ||||||||||
| be afraid to tackle some of these with a smaller telescope. | ||||||||||
| Objects are listed in order of right ascension. Abbreviations are the same as in the | ||||||||||
| Messier and NGC lists. Two columns have been added: one lists the chart where you'll find | ||||||||||
| that object in the Uranometria 2000.0; the last column suggests the minimum aperture needed | ||||||||||
| to see that object. | ||||||||||
| No. | Object | Con | Type | RA (2000) | Dec(2000) | Mag | Size | Chart# | Min. Aperture | Description |
| 01 | NGC 7822 | Cep | E/RN | 00 03.6 | +68°37' | ----- | 60 x 30 | 15 | 30 cm | Large, faint emission nebula; rated `eeF'; also look for emission/reflection nebula Ced 214 (associated with cluster Berkeley 59) 1°S |
| 02 | IC 59 | Cas | E/RN | 00 56.7 | +61 04 | ----- | 10 x 5 | 36 | 20-25 cm | Faint emission/reflection nebulosity paired with IC 63 very close to gamma Cas; requires clean optics; rated as `pF' |
| 03 | NGC 609 | Cas | OC | 01 37.2 | +64 33 | 11.0 | 3.0 | 16 | 25-30 cm | Faint patch at low power; high power needed to resolve this rich cluster (also look for Trumpler 1 cluster 3°S) |
| 04 | IC 1795 | Cas | EN | 02 24.7 | +61 54 | ----- | 27 x 13 | 17 | 20 cm | Brightest part of a complex of neblosity that includes IC 1805 and IC 1848; use a nebula filter |
| 05 | Maffei I | Cas | G-E3 | 02 36.3 | +59 39 | ~14 | 5 x 3 | 38 | 30 cm | Heavily reddened galaxy; very faint; requires large aperture and black skies; nearby Maffei II is probably invisible |
| 06 | NGC 1049 | For | GC | 02 39.7 | -34 29 | 11.0 | 0.6 | 354 | 25-30 cm | Class V globular in dwarf `Fornax System' Local Group galaxy 630 000 light years away; galaxy itself invisible? |
| 07 | NGC 1275 | Per | G-Pec | 03 19.8 | +41 31 | 11.6 | 2.6 x 1.9 | 63 | 20-25 cm | Perseus A exploding galaxy; brightest member of Abell 426 galaxy cluster 300 million light years away; see Webb Volume 5 |
| 08 | 1432/35 | Tau | RN | 03 46.1 | +23 47 | ----- | 30 x 30 | 132 | 10-15 cm | Pleiades nebulosity (also includes IC 349); brightest around Merope; requires transparent skies and clean optics |
| 09 | IC 342 | Cam | G-SBc | 03 46.8 | +68 06 | ~12 | 17 x 17 | 18 | 20-30 cm | Large and diffuse face-on spiral; member of UMa-Cam cloud (Kemble's Cascade of stars also on this Chart) |
| 10 | NGC 1499 | Per | EN | 04 00.7 | +36 37 | ----- | 145 x 40 | 95 | 8-12.5 cm RFT | California Nebula; very large and faint; use a wide-field telescope or big binoculars plus H-Beta filter |
| 11 | NGC 1554/5 | Tau | RN | 04 21.8 | +19 32 | ----- | variable | 133 | 20 cm ? | Hind's Variable Nebula; small reflection nebula around 9-13 magnitude variable star T Tau; use high power; difficulty varies |
| 12 | IC 405 | Aur | E/RN | 05 16.2 | +34 16 | ----- | 30 x 19 | 97 | 20 cm | Flaming Star Nebula; associated with runaway star AE Aurigae; see Burnham's Handbook page 285 (also look for IC 410) |
| 13 | IC 434/B 33 | Ori | E/DN | 05 40.9 | -02 28 | ----- | 60 x 10 | 226 | 15-20 cm | B 33 is the Horsehead Nebula, a dark nebula superimposed on a very faint emission nebula IC 434; use H-Beta filter in dark sky! |
| 14 | Sh 2-276 | Ori | EN | 05 48.0 | +01 -- | ----- | 600 x30! | 226 | 10-15 cm RFT | Barnard's Loop; SNR or interstellar bubble?; difficult to detect due to size; use filter and sweep with wide field |
| 15 | Abell 12 | Ori | PN | 06 02.4 | +09 39 | ~13 | 37" | 181 | 25-30 cm | Also called PK 198 -6.1; faint; not plotted on Uranometria but is on NW edge of mu Orionis; OIII filter required |
| 16 | IC 443 | Gem | SNR | 06 16.9 | +22 47 | ----- | 50 x 40 | 137 | 25-30 cm | Faint supernova remnant very close to eta Gem; use filter (also look for NGC 2174 and Sh 2-247 on this Chart) |
| 17 | J 900 | Gem | PN | 06 25.9 | +17 47 | 12.2 | 8" | 137 | 20 cm | Jonckheere 900; bright starlike planetary; plotted as PK 194 +2.1 in Uranometria; use OIII filter & high power |
| 18 | IC 2177 | Mon | E/RN | 07 05.1 | -10 42 | ----- | 120 x 40 | 273 | 20-30 cm | Eagle Nebula; large, faint; contains bright patches Gum 1 (-10°28'), NGC 2327 (-11°18') & Ced 90 (-12°20') |
| 19 | PK205 +14.1 | Gem | PN | 07 29.0 | +13 15 | ~13 | ~700" | 184 | 20-25 cm | Medusa Nebula or Abell 21; much larger than plotted in Uranometria; impressive in large aperture with OIII filter |
| 20 | NGC 2419 | Lyn | GC | 07 38.1 | +38 53 | 10.4 | 4.1 | 100 | 15-20 cm | At 200 000 light years away the most distant Milky Way globular for amateur telescopes; very small & faint; Class II |
| 21 | PK164 +31.1 | Lyn | PN | 07 57.8 | +53 25 | ~14 | 400" | 43 | 25 cm | Extremely faint with two small components; use OIII filter; sometimes confused with nearby NGC 2474-75 |
| 22 | Leo I | Leo | G-E3 | 10 08.4 | +12 18 | 9.8 | 10.7 x 8.3 | 189 | 30 cm | Dwarf elliptical; satellite of Milky Way; very low surface brightness; 0.3°N of Regulus!; requires clean optics |
| 23 | Abell 1367 | Leo | G's | 11 44.0 | +19 57 | 13-16 | ~60 | 147 | 30-40 cm | Cluster of some 30 or more galaxies within a 1° field near 93 Leonis; see Webb Handbook Volume 5, page 139 |
| 24 | NGC 3172 | UMi | G-? | 11 50.2 | +89 07 | 13.6 | 0.7 x 0.7 | 2 | 25 cm | `Polarissma Borealis' - closest galaxy to the North Celestial Pole; small, faint and otherwise unremarkable |
| 25 | NGC 4236 | Dra | G-SBb | 12 16.7 | +69 28 | 9.6 | 18.6 x 6.9 | 25 | 20-25 cm | Very large, dim barred spiral; a diffuse glow (NGC 4395 on Chart 108 is a similar large diffuse face-on) |
| 26 | Mrk 205 | Dra | Quas | 12 21.6 | +75 18 | 14.5 | stellar | 9 | 30 cm | Markarian 205; a faint star on SW edge of NGC 4319; plotted as a radio source; centre of the red-shift controversy |
| 27 | 3C 273 | Vir | Quas | 12 29.1 | +02 03 | 12-13 | stellar | 238 | 25-30 cm | At 2 to 3 billion light years away one of the most distant objects visible in amateur telescopes; magnitude variable |
| 28 | NGC 4676 | Com | G's | 12 46.2 | +30 44 | 14.1p | ~2 x 1 | 108 | 25 cm | `The Mice' or VV 224 - two classic interacting galaxies; very faint; double nature detectable at high power |
| 29 | Abell 1656 | Com | G's | 13 00.1 | +27 58 | 12-16 | ~60 | 149 | 25-30 cm | Coma Berenices galaxy cluster; very rich; 400 million light years away; brightest member NGC 4889; see Webb Volume 5 |
| 30 | NGC 5053 | Com | GC | 13 16.4 | +17 42 | 9.8 | 10.5 | 150 | 10-20 cm | Faint and very loose globular 1°SE of M53; requires large aperture to resolve; difficult in hazy skies; Class XI |
| 31 | NGC 5897 | Lib | GC | 15 17.4 | -21 01 | 8.6 | 12.6 | 334 | 15-20 cm | Large, faint and loose globular; magnitude 10.9 in Atlas Coeli Catalogue; requires large aperture to resolve; Class XI |
| 32 | Abell 2065 | CrB | G's | 15 22.7 | +27 43 | ~16 | ~30 | 154 | 50 cm | Corona Borealis galaxy cluster; perhaps the most difficult object for amateur telescopes; 1.5 billion light years away; requires superb sky! |
| 33 | NGC 6027 | Ser | G's | 15 59.2 | +20 45 | ~15 | ~2 x 1 | 155 | 40 cm | Seyfert's Sextet (6027 A-F); compact group of 6 small and very faint galaxies; see Burnham's Handbook page 1793 |
| 34 | B 72 | Oph | DN | 17 23.5 | -23 38 | ----- | 30 | 338 | 8-12.5 cm RFT | Barnard's dark S-Nebula or `The Snake'; opacity of 6/6; 1.5°NNE of theta Ophiuchi; area rich in dark nebulas |
| 35 | NGC 6791 | Lyr | OC | 19 20.7 | +37 51 | 9.5 | 16 | 118 | 20-25 cm | Large, faint but very rich open cluster with 300 stars; a faint smear in smaller instruments; Type II 3 r |
| 36 | PK64 +5.1 | Cyg | PN | 19 34.8 | +30 31 | 9.6 | 8" | 118 | 20 cm | Campbell's Hydrogen Star; very bright but very starlike; also catalogued as star BD +30°3639 |
| 37 | M 1-92 | Cyg | RN | 19 36.3 | +29 33 | 11.0 | 12" x 6" | 118 | 25-30 cm | Minkowski 92 or Footprint Nebula; bright, starlike reflection nebula; double at high magnification; associated star invisible |
| 38 | NGC 6822 | Sgr | G-Irr | 19 44.9 | -14 48 | ~11 | 10.2 x 9.5 | 297 | 10-15 cm | Barnard's Galaxy; member of the Local Group; large but very low surface brightness; requires transparent skies |
| 39 | IC 4997 | Sge | PN | 20 20.2 | +16 45 | 10.9 | 2" | 163 | 20 cm | Bright but starlike planetary; the challenge is to see the disk!; blink the field with and without a nebula filter |
| 40 | IC 1318 | Cyg | EN | 20 26.2 | +40 30 | ----- | large | 84 | 8-15cm RFT | Complex of nebulosity around gamma Cygni; multitude of patches in rich starfield; use a very wide field plus filter |
| 41 | PK80 -6.1 | Cyg | PN? | 21 02.3 | +36 42 | 13.5 | 16" | 121 | 25 cm | The `Egg Nebula'; a very small proto-planetary nebula; can owners of large telescopes detect polarization? |
| 42 | IC 1396 | Cep | EN | 21 39.1 | +57 30 | ----- | 170 x 140 | 57 | 10-12.5cm RFT | Extremely large and diffuse area of emission nebulosity; use nebula filter and very wide field optics in dark sky |
| 43 | IC 5146 | Cyg | E/RN | 21 53.5 | +47 16 | ----- | 12 x 12 | 86 | 20-25 cm | Cocoon Nebula; faint and diffuse; use H-Beta filter; at the end of the long filamentary dark nebula is Barnard 168 |
| 44 | NGC 7317-20 | Peg | G's | 22 36.1 | +33 57 | 13-14 | each ~1' | 123 | 25-30 cm | Stephan's Quintet; 0.5°SSW of NGC 7331; easy to pick out 3 or 4 (also look for `companions' to 7331) |
| 45 | Jones 1 | Peg | PN | 23 35.9 | +30 28 | 12.1 | 332" | 124 | 25-30 cm | Plotted as PK104 -29.1 (from Perek & Kohoutek catalogue) in Uranometria; large dim glow; OIII filter required |
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| This list is copyright of the National Centre of the Royal Astronomical Society of Canada | ||||||||||