The RASC's Deep Sky Challenge Objects list

The Royal Astronomical Society of Canada (RASC) has published this list in their yearly Observer's Handbook which is edited by James S. Edgar. The Deep Sky Challenge Objects List was compiled by Alan Dyer and Alister Ling; it is arranged by right ascension.
Credit: Royal Astronomical Society of Canada (RASC)

Object Descriptions


No. Object Con Type R.A. Dec m_v Size U2# min.A
1 NGC 7822 Cep E/RN 00:03.6 +68:37 - 60x30 8 30 2 IC 59 Cas E/RN 00:56.7 +61:04 - 10x5 18 20-25 3 NGC 609 Cas OC 01:37.2 +64:33 11.0 3.0 17 25-30 4 IC 1795 Cas EN 02:24.7 +61:54 - 27x13 29 20 5 Maffei 1 Cas G-E3 02:36.3 +59:39 ~14 5x3 29 30 6 NGC 1049 For GC 02:39.7 -34:29 11.0 0.6 175 25-30 7 NGC 1275 Per G-Pec 03:19.8 +41:31 11.6 2.6x1.9 43 20-25 8 NGC 1432/35 Tau RN 03:46.1 +23:47 30x30 78 10-15 9 IC 342 Cam G-SBc 03:46.8 +68:06 ~12 17x17 16 20-30 10 NGC 1499 Per EN 04:00.7 +36:37 145x40 60 8-12.5 RFT 11 IC 405 Aur E/RN 05:16.2 +34:16 30x19 59 20 12 HH 1 Ori E 05:36.3 -06:45 ~14.5 8" 136 25 13 IC 434/B 33 Ori E/DN 05:40.9 -02:28 60x10 116 15-20 dark sky! 14 Sh 2-276 Ori EN 05:48 +01 600x30! 116 10-15 RFT 15 Abell 12 Ori PN 06:02.4 +09:39 ~13 37" 96 25-30 16 IC 443 Gem SNR 06:16.9 +22:47 50x40 76 25-30 17 J 900 Gem PN 06:25.9 +17:47 12.2 8" 76 20 18 IC 2177 Mon E/RN 07:05.1 -10:42 120x40 135 20-30 19 PK 205+14.1 Gem PN 07:29.0 +13:15 ~13 ~700 95 20-25 20 PK 164+31.1 Lyn PN 07:57.8 +53:25 ~14 6'40" 26 25 21 Leo I Leo G-E3 10:08.4 +12:18 9.8 10.7x8.3 93 30 22 Abell 1367 Leo G's 11:44.0 +19:57 13-16 ~60 72 30-40 23 NGC 3172 UMi G-? 11:50.2 +89:07 13.6 0.7x0.7 1 25 24 NGC 4236 Dra G-SBb 12:16.7 +69:28 9.6 18.6x6.9 13 20-25 25 Mrk 205 Dra Quasar 12:21.6 +75:18 14.5 stellar 5 30 26 3C 273 Vir Quasar 12:29.1 +02:03 12-13 stellar 111 25-30 27 NGC 4676 Com G's 12:46.2 +30:44 14.1p ~ 2x1 53 25 28 Abell 1656 Com G's 13:00.1 +27:58 12-16 ~60 71 25-30 29 NGC 5053 Com GC 13:16.4 +17:42 9.8 10.5 71 10-20 30 NGC 5897 Lib GC 15:17.4 -21:01 8.6 12.6 148 15-20 31 Abell 2065 CrB G's 15:22.7 +27:43 ~16 ~30 69 50 in superb sky! 32 NGC 6027 Ser G's 15:59.2 +20:45 ~15 ~ 2x1 69 40 33 B 72 Oph DN 17:23.5 -23:38 30 146 8-12.5 RFT 34 NGC 6791 Lyr OC 19:20.7 +37:51 9.5 16 48 20-25 35 PK 064+05.1 Cyg PN 19:34.8 +30:31 9.6 8" 48 20 36 M 1-92 Cyg RN 19:36.3 +29:33 11.0 12"x6" 48 25-30 37 NGC 6822 Sgr G-Irr 19:44.9 -14:48 ~11 10.2x9.5 125 10-15 38 Palomar 11 Aql GC 19:45.2 -08:00 9.8 3.2 125 20-30 39 IC 4997 Sge PN 20:20.2 +16:45 10.9 2" 84 20 40 IC 1318 Cyg EN 20:26.2 +40:30 large 32 8-15 RFT 41 PK 080-06.1 Cyg PN? 21:02.3 +36:42 13.5 16" 47 25 42 IC 1396 Cep EN 21:39.1 +57:30 170x140 19 10-12.5 RFT 43 IC 5146 Cyg E/RN 21:53.5 +47:16 12x12 31 20-25 44 NGC 7317-20 Peg G's 22:36.1 +33:57 13-14 ea.~1 46 25-30 45 Jones 1 Peg PN 23:35.9 +30:28 12.1 5'32" 45 25-30
Key:
U2#: Chart number in Uranometria 2000.0 Deep Sky Atlas
Min.A: Minimal Aperture in cm (but also try smaller!)

Remarks

No. Object Remarks
1 NGC 7822 large, faint emission nebula; rated `eeF'; also look for E/R nebula Ced 214 (ass. with cluster Berkeley 59) 1 deg S
2 IC 59 faint emission/reflection nebulosity paired with IC 63 close to gamma Cas; requires clean optics; rated as `pF'
3 NGC 609 faint patch at low power; high power needed to resolve this rich cluster (also look for Trumpler 1 cluster 1 deg S)
4 IC 1795 brightest part of a complex nebulosity that includes IC 1805 and IC 1848; use a nebula filter
5 Maffei 1 heavily reddened galaxy; very faint; requires large aperture and black skies; nearby Maffei II probably invisible
6 NGC 1049 Class V globular in dward `Fornax system' Local Group galaxy 630,000 ly away, galaxy itself invisible ?
7 NGC 1275 Perseus A exploding galaxy; brightest member of Abell 426 gal. cl. 300 million ly away; see Webb vol. 5
8 NGC 1432/35 Pleiades nebulosity (also includes IC 349); brightest around Merope; requires transparent sky and clean optics
9 IC 342 large and diffuse face-on spiral; member of UMa-Cam cloud (Kemble's Cascade of stars also in this chart)
10 NGC 1499 California Nebula; very large and faint; use a wide-field telescope or big binoculars plus H-Beat filter
11 IC 405 Flaming Star Nebula; associated with runaway star AE Aurigae; see Burnham's Handbook page 285 (also look for IC 410)
12 HH 1 Herbig-Haro 1; best with no filter at 250x or more: bipolar jets from forming star; not plotted, 2.5' SW NGC 1999
13 IC 434/B 33 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 Barnard's Loop; SNR or interstellar bubble?; difficult to detect due to size; use filter and sweep with wide field
15 Abell 12 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 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 Jonckheere 900; bright starlike planetary; plotted as PK 194 +2.1 in Uranometria; use OIII filter & high power
18 IC 2177 Eagle Nebula; large, faint; contains bright patches Gum 1 (-10d 28'), NGC 2327 (-11d 18') & Ced 90 (-12d 20')
19 PK 205+14.1 Medusa Nebula or Abell 21; much larger than plotted in Uranometria; impressive in large aperture with OIII filter
20 PK 164+31.1 extremely faint with two small components; use OIII filter; sometimes confused with nearby NGC 2474-75
21 Leo I dwarf elliptical; satellite of Milky Way; very low surface brightness; 0.3deg N of Regulus!; requires clean optics
22 Abell 1367 cluster of some 30 or more galaxies within a 1deg field near 93 Leonis; see Webb Handbook Volume 5, page 139
23 NGC 3172 `Polarissma Borealis' - closest galaxy to the North Celestial Pole; small, faint and otherwise unremarkable
24 NGC 4236 very large, dim barred spiral; a diffuse glow (NGC 4395 on Chart 108 is a similar large diffuse face-on)
25 Mrk 205 Markarian 205; a faint star on SW edge of NGC 4319; plotted as a radio source; centre of the red-shift controversy
26 3C 273 at 2 to 3 billion light years away one of the most distant objects visible in amateur telescopes; magnitude variable
27 NGC 4676 `The Mice' or VV 224 - two classic interacting galaxies; very faint; double nature detectable at high power
28 Abell 1656 Coma Berenices galaxy cluster; very rich; 400 million light years away; brightest member NGC 4889; see Webb Volume 5
29 NGC 5053 faint and very loose globular 1deg SE of M53; requires large aperture to resolve; difficult in hazy skies; Class XI
30 NGC 5897 large, faint and loose globular; magnitude 10.9 in Atlas Coeli Catalogue; requires large aperture to resolve; Class XI
31 Abell 2065 Corona Borealis galaxy cluster; perhaps the most difficult object for amateur telescopes; 1.5 billion light years away; requires superb sky!
32 NGC 6027 Seyfert's Sextet (6027 A-F); compact group of 6 small and very faint galaxies; see Burnham's Handbook page 1793
33 B 72 Barnard's dark S-Nebula or `The Snake'; opacity of 6/6; 1.5 deg NNE of theta Ophiuchi; area rich in dark nebulas
34 NGC 6791 large, faint but very rich open cluster with 300 stars; a faint smear in smaller instruments; Type II 3 r
35 PK 064+05.1 Campbell's Hydrogen Star; very bright but very starlike; also catalogued as star BD +30 3639
36 M 1-92 Minkowski 92 or Footprint Nebula; bright, starlike reflection nebula; double at high magnification; associated star invisible
37 NGC 6822 Barnard's Galaxy; member of the Local Group; large but very low surface brightness; requires transparent skies
38 Palomar 11 brightest of 15 heavily reddened GCs found on Sky Survey; magnitude is misleading. 11 Terzan GCs more challenging
39 IC 4997 bright but starlike planetary; the challenge is to see the disk!; blink the field with and without a nebula filter
40 IC 1318 complex of nebulosity around gamma Cygni; multitude of patches in rich starfield; use a very wide field plus filter
41 PK 080-06.1 the `Egg Nebula'; a very small proto-planetary nebula; can owners of large telescopes detect polarization?
42 IC 1396 extremely large and diffuse area of emission nebulosity; use nebula filter and very wide field optics in dark sky
43 IC 5146 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 Stephan's Quintet; 0.5 deg SSW of NGC 7331; easy to pick out 3 or 4 (also look for `companions' to 7331)
45 Jones 1 plotted as PK 104-29.1 (from Perek & Kohoutek catalogue) in Uranometria; large dim glow; OIII filter required

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    Last Modification: October 2, 2018