Messier 40

40 final

Object:   M40 (Winnecke 4) Date:               2019 February 24
Type:              Double star
Constellation:           Ursa Major Time & altitude:          21.25 UT   52º
Catalogue data: Seeing (5 high):                               3/5
            R.A:                12h 22m Transparency (5 high):                   4/5
            Dec:                58º 05 Telescope:     0.5m f4.1  Dob.
            Magnitude     8 Eyepiece       8mm Ethos                x260
            Size (mins) Filters:            None


In 50-plus years of observing, this is the first time I have looked at M40. Although it is ‘just’ a wide, nearly equal magnitude double star, the 23 arcmin field of the 8mm Ethos holds interest with two galaxies on show.

The more conspicuous galaxy is NGC 4290, 12.7m and 2.4×1.8’. It has a stellar nucleus and a noticeable elongated core. One gets the impression of fleeting detail at the limit of resolution. Interestingly the long axis of the core lies NE-SW, a lot different to the long axis of the oval halo which is E-W. The edge of the halo is not well-defined but fades gently away to the sky background.

The other is NGC 4284 is 14.3m and 2.5×1.1’. This galaxy appeared round not oval.

A third galaxy, not seen, is 17thm. PGC 39934 lying between M40 and NGC 4290.