M106 in Canes Venatici

Field Centred at:
RA: 12h 18m 41.0s
Dec: +47° 17′ 57.3″
Field 25.2×18.9 arcmin, Up is 184° E of N

M106 (with NGC4248) - LRGBM106 (NGC 4258) is an intermediate type spiral galaxy located at a distance of 23.7 (± 1.5) million light years in the constellation of Canes Venatici. Also shown in this frame is the small spiral galaxy NGC 4248 (lower left of frame).

M106 was discovered by Pierre Méchain in 1781 and has an active nucleus and is one of the best known Type 2 Seyfert galaxies. It also is host to a water vapour megamaser that is visible in the 22GHz frequency of ortho-H20 (water molecules where the spins of the two hydrogen atoms are aligned). 

M106 also has significant hydrogen emission around the core – one of the brighter “jets” is just visible in the close up (at 150%)  – taking hydrogen alpha data would show this up to a much greater extent, but this is something that will have to follow later when skies are clear!

In June 1995, the following letter was published in Astronomy & Astrophysics from Burbidge concerning two bright Xray sources symmetrically placed about NGC 4258 (M106):  1995A&A…298L…1B

Burbidge found that these objects were in fact quasars, with redshifts of 0.39 (J1218+472) and 0.65 (J1219+473). Burbidge, who worked closely with Fred Hoyle, argues (as does Halton Arp in a later paper), that the association of these QSOs with M106 is not accidental, and that the redshifts arise from the ejection velocities of the objects from the host (pretty quick!).

All three scientists were strong proponents of non-Big Bang cosmologies though, so you may detect a slight bias here: later work (eg , appears to suggest one of these (J1281+472) is associated with a cluster at redshift z~0.3, and that X-Ray luminosity and cluster temperatures are entirely consistent. So, this may well be a case of line of sight.

M106, with QSOs marked
M106 with annotated QSOs.

In the field as well (see the image, left), is a further QSO with redshift ~1.04 – theory places this at around 8Gly in a flat cosmology.


Image was taken with an ST2000XM through a 14″ Newtonian at f4.53 (fl = 1584mm) from West Oxfordshire on Feb 13th/15th 2018. Exposures lengths are:

Lum: 5h35m (56x5m + 21x3m) 
R: 1h45m (21 x 5m, 2×2 bin)
G: 1h20m (16 x 5m, 2×2 bin)
B: 1h20m (16 x 5m, 2×2 bin)

The luminance data on its own is shown below.M106 (with NGC4248) - Luminance Channel


Merope & Tempel’s Nebula (NGC1435)

Image centred at:
RA: 03° 46′ 18″
Dec: +23° 56′ 04″
Field of view: 25.46′ x 18.82′

Merope & NGC1435 (Tempel's Nebula)The Pleiades open cluster in Taurus is one of the brightest and most recognisable objects int he winter sky. As a first LRGB image using the 14″ Newtonian, and to test the setup of the off-axis guider, I imaged the area around Merope (23 Tau). This was also the first use of a Bahtinov mask that I got laser cut by Oxford Hackspace. The focusing mask works excellently – this should be a real plus, especially for any planetary/lunar work.

The particular area of nebulosity imaged here around Merope was discovered by Wilhelm Tempel on October 19th, 1859, and is catalogued as NGC1435. The dust isn’t in fact the nebula from which the cluster formed, rather that the Pleiades happen to be travelling through a particularly dense part of interstellar medium. This dust scatters blue light from the cluster members, resulting in the reflection nebula visible to us.

The image shows strong diffraction spikes from the secondary spider, as would be expected. There’s also further diffraction visible around the brightest stars dark shadowing present at 60 degree angles, which is the result of the mirror retaining “clips” (they are not actually clips – they are part of the cell in the case of the 9 point Orion Optics mirror cell). To remedy this would require a mask to be added over the outer edge of the mirror to cover these over – this is maybe something I’ll think about making in the future to help deal with tricky situations like this! 

The additional dark shadow pointing to the right appears to be the focuser drawtube intruding on the internal light path inside the scope – that’s probably something that can only be cured by either a shorter drawtube, or shortening the truss tubes. Again. Maybe I’ll wait in case I decide to change coma corrector at some point, in which case it’ll probably need a change to the focal plane position anyway.

The image was taken on the evening of the 7th Jan 2018 through the 14″ (350mm) Newtonian, with an ST2000XM and an MPCC v1 coma corrector. Total exposure was “only” 2h 32m (L: 59m (20x1m, 13x3m), RGB: 31m (10x1m, 7x3m) each channel). Processing in Pixinsight and Photoshop CS4.

Circumzenithal Arc

Circumzenithal Arc - Abingdon, 15th Aug 2008

Saw this circumzenithal arc on Friday 15th from Abingdon. Looks much like an upside down rainbow above the sun (which needs to be lower than 33 degrees or so for this to occur) – it occurs due to horizontally orientated ice crystals high in the upper atmosphere.

Only had the camera on my phone so the image is a bit ropey, but hopefully clear enough…