Tag Archives: 14″ Newt

M96 in Leo: An Imperfect Spiral Galaxy

M96 - Spiral in Leo

Messier 96 is an imperfect, intermediate spiral galaxy in the constellation of Leo, at a distance of approximately 30 million light years. It is a highly asymmetric galaxy – the gas and dust is not evenly spread through its spiral arms, and the core doesn’t appear to be exactly at the galaxy’s centre. This is thought to have arisen due to interactions with other nearby galaxies (eg M95 which is about 40′ to the west of M96 from our viewpoint).

The spiral arms show bright knots of young hot stars (more easily visible in colour images) indicating recent starbirth, and visible through the outer dusty reaches are many background galaxies including the edge on galaxy 2MFGC 8391 shown here to the lower right (north-east) of the centre of M96. 

Also in this image is my current distance record (though not something I’ve tried to push!) – QSO J104619.26+115223.4 is present (and annotated in the image shown) – this quasar has a measured redshift of z=2.83, placing it at a distance of of 11.4 billion light years (light travel time) in our current best estimates of the universe’s parameters. This quasar shines dimly at a magnitude of 20.5 in the R band. Somewhat closer to home, but equally faint, is the dwarf galaxy Leo 15 (also annotated).

The image was taken on 22 Feb 2018 and 13-14 March 2018 and consists of 7hrs of exposure through the luminance filter (84 x 5min subexposures) using an ST2000XM on a 350mm Newtonian at 1584mm focal length. Processing and reduction took place in Pixinsight.

Weather was very poor this spring and I had no chance to get any decent colour data to produce a finished LRGB version – will have to hold this one over until next year…

Field (25’x18.6′) centred at:
RA: 10h 46m 44s
Dec: +11° 49′ 23″
Up is 184° E of N

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 , http://iopscience.iop.org/article/10.1086/309327/pdf) 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.

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

 

 

 

 

 

EDIT: This image was selected in 2nd place for the “A Galaxy, Far, Far Away” challenge on Stargazers Lounge – see: https://stargazerslounge.com/topic/314249-imaging-challenge-11-galaxies-winners/

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.

Nov 2017 Lunar Mosaic

The 4th November 2017 gave me clear skies with a very bright moon in the sky – this gave me  good opportunity to use the rebuilt 14″ Newtonian scope for some imaging work, now that the scope truss tubes have been correctly milled down to the right length. 

Using the ASI120MM camera with a 742nm nr-IR filter, I imaged the moon at its native focal length (1582mm), using Firecapture to grab the video. The data totalled 56GB in all!

The finished mosaic consists of 18 frames: each of these was the result of stacking the best 12%  (quality-wise) of 3000 frames. Each of the frames were 0.18ms each (with gain set to 54), and were captured at around 31 frames per second.  To try to avoid issues with exposure mismatch, all the exposure details were kept identical throughout the 36 minutes  or so it took to complete the whole set of videos across the face of the moon.

99% Moon on 2017-11-04
Mosaic of 99% Moon on 2017-11-04 at 80% resolution (3MB image size)

The videos captured were aligned and stacked using Autostakkert2, and each of the stacked images were processed using identical wavelet settings in Registax6. 

To create the mosaic itself, I took all the images into Microsoft Image Composite Editor (ICE) and let it get on with the process of aligning and stitching the images together. It did a remarkably good job! I had also tried the Photomerge function in CS4, but ICE did a better job here: Photomerge was good but left a couple of slight merging artifacts – misalignments on the limb, mostly. 

Final processing took place in Photoshop (smart sharpening, levels, curves, etc) with the result being a 20Mpixel image weighing in at 7+ MB for a high quality jpg. Here, I’ve reduced the image to 80% of the original resolution to aid web viewing!

Images were taken starting at 2215UT from West Oxfordshire, UK. 

Lunar Imaging Gallery – 16th May 2016

Some further lunar work – as before I worked using the ASI120MM in combination with a 2x Barlow lens and the 742nm near-IR filter through the 350mm Newtonian.

A productive evening, with six images of good quality in what was at times fairly good seeing – I would like to try running at a slightly higher scale (by using a different Barlow). i do have a 4x Imagemate, but I’m not sure the quality or the resultant focal length would work quite as well.

As it turned out, this was an evening where I bagged a few of the double ringed (concentric) craters on the moon, as well as some interesting Rille features and domes.

Images are as follows:

Clavius with Longomontanus, Scheiner and Blancanus – a good amount of detail in this image and I’m especially pleased with the detail within Rutherfurd (on the southern edge of Clavius). Street M is visible with a small concentric craterlet within.

Longomontanus and Clavius, 2016-05-16

Moretus, with some very good detail coming out of the wall and surrounds. The lunar south pole region (with Newton tucked just behind the hills) is to the bottom of the image.

Moretus, 2016-05-16

Copernicus – a classic lunar crater, and one where I’ve got a much better result than I’ve previously acheived. I particularly like the collapsed edge visible to the south – perhaps a little more scale might just let me sharpen up the detail within the crater a little… Also visible are the Hortensius domes (to the left in the image) lying just to the north of the crater of the same name – lunar domes are shield volcanoes which often have a small craterlet at the peak.

Copernicus, 2016-05-16

 

Rimae Hippalus and surrounds. So much going on in this region – bullialdus by itself is a nice looking crater, and nearby the complex rille structures of Rimae Hippalus cut across Hippalus and the surrounding regions, leading up to Agatharchides. The lunar dome Kies Pi is easily visible and concentric crater Marth in Palus Epidemarium is also present in the bottom right of the image.

Rimae Hippalus and Surrounds, 2016-05-17

Another busy nearby field, showing Pitatus, concentric craters Hesiodus A and Marth. Lots of rilles also visible, including Rimae Hippalus, Rimae Ramsden, Rima Hesiodus, rilles in Pitatus, and Rima Campanus cutting between Campanus and Mercator. Kies Pi is again obvious.

Mare Nubium and Palus Epidemiarus, 2016-05-16

A view north of Bullialdus including the interesting “rippled” texture between Darney and Euclides.

Bullialdus and Mare Nubium, 2016-05-16

The last two make a rather nice mosaic, though this was a quick job and I haven’t tried too hard to eliminate the edge of field noise, or the slight mismatch between levels.

Bullialdus Region - Mosaic