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Hi Ivan & All,
Can add a confirming observation of QSO 2204-573 tonight just before 10.30pm, 63.5cm x347. SQML reading was 21.88.
Using my 63.5cm f/5 Newtonian tonight about 10.20pm, from NGC 7205, I slewed the ‘scope 20 arc-minutes N locating the wide, magnitudes +11/+11 pair separated by about 30” (marked in the image). This is where I swapped from moderate (x195) to high magnification (9mm TI Nagler @ x347 and 14 arc-minute diameter true field in my case). QSO 2204-573 is just 4 arc-minutes WSW from this pair and less than an arc-minute NE of the centre star in a compact straight-line of three stars (underlined in the image), all about magnitude +14.5 – +15.5.
Pretty simple thus far, now it gets tricky: QSO 2204-573’s true V magnitude is +17.2! I have seen a number of stars as faint with this telescope, but they take concentration, perseverance and a very dark, transparent sky. Patience and a number of minutes with no light of any sort (to permit profound dark adaptation) is mandatory. After I was convinced I had the spot precisely centred and was fully dark-adapted, I observed intently for about five minutes and during that time I glimpsed QSO 2204-573 momentarily at least twenty times. Toward the end, I could nearly hold it continuously with averted vision. The small, apparently edge-on galaxy PGC 129038 (marked on the image) was similarly seen intermittently and was probably slightly easier. This galaxy has no calculated recessional velocity and its distance is not known. It has a B magnitude of +16.1 so its true V magnitude is approximately mid-15s – but is an extended (ie non-stellar) object with lower surface-brightness than the QSO.
Why did I bother to sleuth-down QSO 2204-573? It has a measured redshift of 2.73 and a recessional velocity of 259,486km/sec (yup, that’s just over 86% of c!). Derived from that, adopting a Hubble constant (Ho) of 70.4km/sec/Mpc and adopting some standard assumptions as to our Universe’s geometry, implies a distance/look-back time of 12 billion light years (+/- a little bit) – or about 87% of the way across the observable Universe. The light I saw tonight was emitted when our Universe was no more than the equivalent of a pre-pubescent child -- ~1.8 Gyrs old or approximately 13% of its present age.
Thanks for the heads-up Ivan.
Best,
L.
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