From 6993f35cfc5d515156713e11a99c7d97dd4db74e Mon Sep 17 00:00:00 2001 From: Laurence Date: Sat, 18 Jul 2026 20:58:45 +0100 Subject: [PATCH] Southern targets guide: objects invisible from the UK MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. --- README.md | 2 + TARGETS.md | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++ state/TODO.md | 3 ++ 3 files changed, 130 insertions(+) create mode 100644 TARGETS.md diff --git a/README.md b/README.md index df7dc77..1007f33 100644 --- a/README.md +++ b/README.md @@ -6,6 +6,8 @@ book for a given target. - **[TELESCOPES.md](TELESCOPES.md)**: the full review, grouped by observatory, with a "choosing a telescope" guide at the end. +- **[TARGETS.md](TARGETS.md)**: southern-sky targets invisible from the UK, matched + to scopes and to the time of year to book them. - **[data/itelescope-telescopes.csv](data/itelescope-telescopes.csv)**: snapshot of the network's maintained specs sheet (source of truth for the numbers). - **state/**: project state under the Default Workflow. diff --git a/TARGETS.md b/TARGETS.md new file mode 100644 index 0000000..9187947 --- /dev/null +++ b/TARGETS.md @@ -0,0 +1,125 @@ +# 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](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. diff --git a/state/TODO.md b/state/TODO.md index c0fe66a..e699da8 100644 --- a/state/TODO.md +++ b/state/TODO.md @@ -9,6 +9,9 @@ - 2026-07-17: specs sheet snapshotted to data/itelescope-telescopes.csv (24 scopes). - 2026-07-17: TELESCOPES.md written: per-scope reviews for all 23 active telescopes plus a choosing guide (T74 noted as in commissioning, no specs published). +- 2026-07-18: TARGETS.md written: southern targets invisible from the UK (dec tiers + from lat 51.5°N), matched to Q62/X07 scopes, seasonal booking calendar, and a + July-August starter campaign (T33 free, T71 narrowband, T73 galaxy, T8 LMC later). ## In progress