January Skynotes: Eridanus, a neglected winter constellation

These notes are taken from Christopher Taylor's observations of Eridanus over the years, all using the McIver Paton telescope. Click the images for larger versions.


Eridanus, Jan. 1998, 12.5-inch


From: Christopher T.
Sent: 03 March 2013 15:58
To: HCO.
Subject: LAST NIGHT.

Dear All,

A good session at the telescope last night, something which doesn’t happen all that often at our monthly HCO meetings. The mirror of the 30-inch is still in the w’shop at Walthamstow but should be back v. shortly; in its absence, we had some good views in the 12.5-inch in quite a good , if not superlative, sky: Jupiter+moons set very prettily in a starry field in the midst of the Hyades at low power, the ‘Great’ ‘Red’ Spot clearly visible almost on the centre-line of the disk at x238 in quite decent definition; an attractive but little-known colour-contrasted double star 32 Eridani, from the list of such circulated a while back; a very interesting triple-star system omicron-2 Eridani, a true 3-body system, whose second star is the only white dwarf EASILY visible in a telescope and whose third is an even dimmer red dwarf, all clearly visible at x238; one of the brighter planetaries, NGC 1535 Eridani, a small fuzz-ball quickly glimpsed in x75 wide-angle (only, as about to disappear behind western trees - this does show a lot more in the 12.5-inch at higher power); Rigel + Rigel B, the opposite extreme to omicron Eri. in the stellar ‘zoo’, a nice view at x238 - so within a few minutes at the eyepiece we had ranged from omicron Eri. C at 0.0008 of solar luminosity to Rigel at 40,000 solar, a ratio of 50 million: 1 in stellar brightness!; and finally, Orion’s Great Nebula*, a churning mass of primordial chaos at x238. This part of the heavens is truly an astrophysicist’s paradise.

For those who may be interested in extreme astronomy/astrophysics, see the entry in ‘Burnham’s Handbook’ for omicron Eridani and its famous white dwarf.

                                           Yours randomly,       Christopher.

* (Note added Jan. 2016): see next month’s Skynotes for more Hanwell obs. of  M42 Orionis.


Eridanus, 12.5-inch, 5.3.13