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itelescope/TARGETS.md
Laurence 6993f35cfc Southern targets guide: objects invisible from the UK 
Adds TARGETS.md, a target guide for the southern iTelescope sites (Siding
Spring Q62, Deep Sky Chile X07) built around UK visibility: from lat 51.5°N
anything below dec -38° never rises and dec -25° to -38° culminates under
~15° altitude. Targets are tiered accordingly (never visible vs hopeless),
grouped by region (Magellanic Clouds, Carina/Crux, Centaurus, Ara/Scorpius
tail, far-southern galaxies, SNR/planetaries), and each is matched to the
best scope from TELESCOPES.md with the field-of-view reasoning in the notes.

Includes a seasonal booking calendar (evening sky by quarter from the
southern sites, with the Q62 30-35° minimum-elevation caveat), a suggested
first campaign for July-August (free T33 globulars, T71 narrowband on Ara/
Scorpius, T73 on NGC 6744, then T8 on the Magellanic Clouds in Oct-Nov),
and cost-shape notes (fast scopes for nebulae, dark-of-moon for LRGB).

README links the new guide; state/TODO.md records the addition.
2026-07-18 20:58:45 +01:00

6.2 KiB
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Southern targets: what the UK can never show you

A target guide for imaging objects that are invisible (or hopeless) from the UK, using the southern half of the iTelescope network: Siding Spring, Australia (Q62) and Deep Sky Chile (X07). Companion to TELESCOPES.md.

The visibility rule from the UK

From latitude 51.5°N (southern England), an object's maximum altitude is 90° - 51.5° + declination:

  • Dec below about -38°: never rises. These objects cannot be imaged from the UK at all, ever.
  • Dec -25° to -38°: technically rises, practically hopeless. Culminates under ~15° altitude, buried in atmosphere and murk.
  • Dec -10° to -25°: imageable from the UK but always low and compromised; far better from the southern sites.

Everything below is grouped by those tiers, then matched to scopes and to the time of year when it is best placed from the southern sites.

Tier 1: never visible from the UK (dec < -38°)

The Magellanic Clouds (the headline act)

Target Dec Best scope Notes
Large Magellanic Cloud -69° T8 The whole LMC just fits T8's 4 x 4 degree field
Tarantula Nebula (NGC 2070) -69° T73, T17 Core detail; the finest emission nebula in either sky
Small Magellanic Cloud + 47 Tucanae -72° T8 Both in a single T8 frame, a unique composition
47 Tucanae (NGC 104) alone -72° T33 (free), T73 Second-finest globular in the sky

Carina and Crux region

Target Dec Best scope Notes
Eta Carinae Nebula (NGC 3372) -59° T71 Fills T71's 2.7 x 1.8 degree field perfectly; narrowband showpiece
Carina to Crux widefield -60° T70 The richest stretch of the Milky Way in one 8-degree frame
Southern Pleiades (IC 2602) -64° T71, T75 Bright open cluster
Running Chicken (IC 2944) -63° T71, T75 Emission nebula with Bok globules
Wishing Well Cluster (NGC 3532) -58° T71 Reportedly the best open cluster in the sky
Coalsack + Southern Cross -60° T70 Dark nebula composition

Centaurus and the southern globulars

Target Dec Best scope Notes
Omega Centauri (NGC 5139) -47° T59, T17 The largest globular cluster known; needs the ~40 arcmin fields
Centaurus A (NGC 5128) -43° T17, T32, T73 Iconic dust-lane radio galaxy
NGC 4945 -49° T73 Big edge-on spiral, underimaged
NGC 6752 (Pavo globular) -60° T33 (free) Third-brightest globular

Ara, Norma and the Scorpius tail

Target Dec Best scope Notes
Fighting Dragons of Ara (NGC 6188) -49° T71 Dramatic narrowband target
Prawn Nebula (IC 4628) -40° T71, T75 Large, faint, great in Ha
NGC 6231 + Table of Scorpius -42° T71 Rich cluster region

Far-southern galaxies

Target Dec Best scope Notes
NGC 6744 (Pavo) -63° T73, T17 Milky Way lookalike spiral
NGC 1313 (Topsy-Turvy) -66° T73 Distorted starburst spiral
NGC 1566 (Spanish Dancer) -55° T73 Grand-design face-on spiral
NGC 2070 region galaxies -69° T17 See Magellanic section

Southern nebulae, supernova remnants and planetaries

Target Dec Best scope Notes
Vela SNR -45° T70 Huge filamentary shell, needs the 8-degree field
Gum Nebula -43° T70 36 degrees across; even T70 mosaics it
Southern Ring (NGC 3132) -40° T73 Small bright planetary
Toby Jug Nebula (IC 2220) -59° T73 Reflection nebula

Tier 2: hopeless from the UK (dec -25° to -38°), excellent from the south

Target Dec Best scope Notes
Cat's Paw (NGC 6334) -36° T71 Narrowband showpiece
War and Peace (NGC 6357) -34° T71 Pairs with the Cat's Paw in one T75 framing
NGC 1365 (Great Barred Spiral) -36° T73, T17 The archetypal barred spiral, Fornax
Fornax cluster core -35° T17, T32 Galaxy cluster field
M83 (Southern Pinwheel) -30° T73, T17 Face-on spiral, superb from Q62/X07
NGC 300 and NGC 55 (Sculptor) -37°/-39° T17, T75 Nearby resolved spirals
NGC 253 (Sculptor Galaxy) -25° T17, T32 Huge dusty starburst, low and ruined from the UK
Corona Australis dust complex -37° T71, T75 Reflection nebula and dust river

When to book what (from the southern sites)

Seasons refer to what is well placed in the evening-to-midnight sky at Siding Spring and Deep Sky Chile. Siding Spring scopes have 30-35 degree minimum elevation limits, so aim within a few hours of culmination; T70 in Chile can go to the horizon.

  • Jan-Mar: Tarantula and the LMC, NGC 1313, Vela SNR and the Gum Nebula, Carina rising late evening.
  • Apr-Jun: Eta Carinae at its best, Crux and the Coalsack, Omega Centauri, Centaurus A, NGC 4945, the Musca dark nebulae.
  • Jul-Sep (now): the Scorpius tail and Ara at the zenith: Cat's Paw, War and Peace, Prawn, NGC 6188, NGC 6231; NGC 6744; Corona Australis; 47 Tucanae and the SMC in the second half of the night.
  • Oct-Dec: Magellanic Cloud prime time, 47 Tucanae, Sculptor galaxies (NGC 253, 55, 300), Fornax cluster and NGC 1365, NGC 1566.

A sensible first campaign (July-August)

  1. Free warm-up on T33 (30 min/day, Siding Spring): 47 Tucanae or NGC 6752 in LRGB across a few nights. Costs nothing, learns the booking system.
  2. T71 narrowband run (Chile, f/2.8): NGC 6188 or the Cat's Paw + War and Peace region. Fast optics keep the bill down; use the standard 300 s calibrated subs.
  3. T73 galaxy shot: NGC 6744, currently well placed, as an LRGB target.
  4. Book ahead for October-November: T8 for the LMC (or SMC + 47 Tuc in one frame): the single most "you cannot do this from the UK" image on the network.

Cost-shape notes

  • Fast scopes (T71 f/2.8, T75 f/3.8, T70 f/3.5) reach depth in the least imaging time, which is what you pay for: prefer them for nebulae.
  • The two free scopes cover both hemispheres of this list poorly (T68 is northern) but T33 covers southern globulars and compact targets well.
  • Moonlight: narrowband targets (Carina, Ara, Scorpius nebulae) tolerate moon; save galaxy and globular time (T73, T17, T8 LRGB) for dark-of-moon bookings.