Category Archives: astronomy

astroimaging, astronomy, open clusters

M36, Carbon Star OW Aur & Holoea

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Field Centred at: 
RA: 05h 36m 25s
Dec: +34° 07′ 24″
Up is -89.8 degrees E of N
(Plate solve by nova.astrometry.net)

M36 in AurigaM36 is one of the three bright open clusters in Auriga. It was catalogued by Charles Messier on the night of 2nd Sept 1764, though it had been previously discovered at least 110 years prior to this by Italian astronomer Giovanni Batista Hodierna. Despite being one of the fainter open clusters in Messier’s catalogue (though M38, also in Auriga is the fainter of the three), it is visible with the naked eye from a dark site.

There are about 60 stars in the cluster itself at a distance of about 4100 light years. It is very similar in extent to the Pleiades, and if it was at the same distance, it would likely appear just as bright!

In this image to the lower left (south west – north is to the right here) there is the deep red variable star OW Aur. This is another carbon star, similar to V358 Aur as imaged near to M37. 

Holoea - YSO in M36
Holoea – YSO in M36

Also of note in the object, though only just visible at this scale (shown at 200% scale on left) is an enigmatic object with the name “Holoea” – this is an object that has a tail like structure with high velocity outflows, and is likely to be a young stellar object. Details on the discovery and analysis of this object can be found at 1996A&A…305..936M (Magnier, E. A.; Waters, L. B. F. M.; Kuan, Y.-J.; Chu, Y.-H.; Taylor, A. R.; Matthews, H. E.; Martin, E. L.)

The data presented here was taken on the evening of 30th Nov 2016 as an opportune target while waiting for another object to be in a favourable position. As such, exposures were fairly short, totalling 45:40:40 R:G:B (all unbinned, 5min sub exposures). Reduction/processing was performed in Pixinsight with final tweaks in Photoshop. During processing in PI, I generated a pseudo-Luminance frame from the combined RGB data and then merged this back to form the LRGB image shown. 

astroimaging, astronomy, nebulae

M78 – Reflection, Dust and Star Birth in Orion

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Field Centred at (plate-solve by nova.astrometry.net):
RA: 05h 46m 40.4s
Dec: +00° 12′ 10.2″
North is up

M78 in Orion in LRGBOrion is a rich area for deep-sky objects, and it’s somewhat of a shame that M78 is so often overlooked, with the Orion Nebula, Horsehead and Flame taking centre stage.

There are three main areas of reflection nebulosity present here, the larger, bluer of which (M78 itself) is illuminated by the stars HD 38563A/38563B and appears split in two by an obscuring dark dust lane. The area of nebulosity to the west (right) of M78 itself is catalogued as NGC 2064 and NGC 2067, though, the actual catalogue designations become hard to follow as the whole region shows nebulosity that merges into one combined region…

The smaller area of nebulosity to the north (NGC 2071) is illuminated by HD 290861 and is encompassed by further blue reflection nebula. It is also surrounded by the continuation of the sinuous dust lane.

Herbig Haro 22, 24 & McNeil's Nebula
Herbig Haro 22, 24 & McNeil’s Nebula

The dust in this image hides a lot of hidden activity – some of which is revealed in the image and is highlighted in the crop (displayed at 200%) – this shows Herbig-Haro 22 and 24 along with McNeil’s Nebula (top-centre). Within these regions, newly born stars start to illuminate gas around their birthplace, while jets of material from these stars collide with surrounding gas and dust.

T Tauri type stars are also found in these dusty regions. These are stars that do not have a core hot enough to trigger hydrogen fusion (but may burn lithium), and are not yet in hydrostatic equilibrium, whereby gravitational forces are balanced by outward pressure due to heat from within the star. Heat is produced by gravitational contraction during this intermediate phase between a true protostar and a main sequence star. It does offer a look back in time to a phase our own sun would have passed through before the formation of the solar system  from the solar nebula.

Bernes 100
Bernes 100

Finally, to the top (north) of the image, we start to see a large area of HII emission that merges into Barnard’s Loop. Within this, there is an interesting bright nebula near HD 290857 with only one reference that I’ve been able to find through Simbad. The reference comes from a 1977 paper, “A catalogue of bright nebulosities in opaque dust clouds” (Bernes C., 1977A&AS…29…65B), and as such the nebula gets the classification Be 100 (listed as [B77] 100 in Simbad). The nebula (shown) forms part of the much larger L1630 molecular cloud.

Image was taken using William Optics FLT110 with FLAT4 reducer; SBIG ST2000XM; Losmandy Titan with Gemini 2. 

L: 6h45m (21x15m + 9x10m)
R: 3h (18x10m, 2×2 bin)
G: 2h30m (15x10m, 2×2 bin)
B: 2h20m (14x10m, 2×2 bin)

Reduction and processing in Pixinsight and Photoshop CS4. 

Images acquired Nov/Dec 2016 from Oxfordshire, UK.

astroimaging, astronomy, galaxies

M33 – The Triangulum Galaxy

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RA: 01h 33m 54.0s
Dec: +30° 40′ 15.8″
Up is -89.8°E of N
(Plate solve by nova.astrometry.net)
M33 - Triangulum GalaxyMessier 33 is a spiral galaxy in the constellation of Triangulum, and is sometimes called the Pinwheel  Galaxy, a name it shares with M101, It is the third largest member of the Local Group of galaxies with a diameter of about 60,000 light years; the two larger members being our Milky Way and the Andromeda Galaxy (M31). There is suggestion that M33 and Andromeda have experienced an encounter at some point in the past (and will do again in the future!).

M33 is one of the most distant objects visible to the naked eye, but it is a relatively diffuse galaxy, and so it’s visibility with the naked eye and through binoculars is strongly affected by light pollution and sky transparency – in this respect, M31 is far more visible to the naked eye. 

There are lots of H-II star forming regions within M33 that are visible as pinkish areas of hydrogen emission in the spiral arms. The largest of these is NGC604 which was catalogued independently of the galaxy core by William Herschel. This area is probably very similar to the Orion Nebula in many ways, and can be found to the north-east (upper-right) of the core of the galaxy (north is to the right in the images).

The images were all taken across several nights in November 2016 (7th, 28th, 29th) from West Oxfordshire with an SBIG ST-2000XM though a William Optics FLT110, all mounted on the Losmandy Titan. Exposures were as follows:

L:R:G:B
310 (31x10m) : 95 : 90 : 80 (RGB in 5m subs, 2×2 binned)
All exposures taken at -20°C.

Reduction and processing performed in Pixinsight and Photoshop. The processing of this object proved tricky. The galaxy largely fills the field and leaves relatively little background to work with in running DBE processes. This left several colour casts and gradients that I needed to manually remove within Photoshop – not an easy task…  

M33 HDR EnhancedAlso included here is a luminance only channel using the L channel data, that has been processed using HDR Multiscale Transform, Local Histogram Equalization and TGV Denoise to reveal to a greater extent the structure of the galaxy – in many ways this might be regarded as “over-processed”, but an interesting take on the galaxy nevertheless. 

astroimaging, astronomy, open clusters

M37 & Carbon Star V358 Aur

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RA: 05h 52m 16.8s
Dec: +32° 32′ 07.6″
Up is -179 degrees E of N
(Plate-solve by nova.astrometry.net)

I took a short set of subs late at the end of an imaging run on the Bubble Nebula, concentrating on the open cluster M37 in Auriga. 

As it was so late, images were restricted to RGB 35:35:35 (all 7x5min subs) unbinned at 1×1, though I find I get better star colours with RGB only processing. They were processed in Pixinsight as the first RGB image I’d put through it – while there was a bit of getting used to the order of the processes required and the methods of colour balancing and combining, I think I managed to get the result somewhere near to what I was after, while also preserving star colour in what is quite a rich open cluster. 

M37 in AurigaTo the bottom (centre-left) of the frame, there is a particularly red star which is the irregular variable star V358 Aur (Magnitude V 12.2, R 11.4). This is a carbon star (ie class C), which are cool (often giant) stars with dominant absorption lines from C2 molecules (the Swan bands), as well as absorption features from other larger carbon compounds. These compounds give the outer atmosphere of the stars a “sooty” makeup and a striking red colour. 

All subs taken on 6th Nov 2016 from 01:45UT. 

astroimaging, astronomy, equipment, nebulae, open clusters

Bubble Nebula + M52; Equipment Updates

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The past few months have seen some changes to my equipment – unfortunately the biggest (or most expensive) change was due to my original Gemini 1 controller dying. The mount is back in action after I upgraded to a Gemini 2 from Losmandy via an existing owner trade-in. Good news is that the mount appears to be working well, though still needs PEC sorting and full building of pointing models.

I’ve also got a 0.8x reducer/flattener for the William Optics FLT110 (this is the latest model of the William Optics FLAT4 reducer), allowing me a larger field of view on the SBIG ST2000X, a flatter, faster field, and also the ability to mount a recently acquired, astro-modded Canon 350d on there as well – I look forward to trying to image the Pleiades and the Orion Nebula using a sensitive, wide field arrangement this winter… I also have started to use Pixinsight for processing images; while it’s been a learning curve for me, I feel I’m starting to get somewhere in using it, and think it could be a very powerful tool.

Bubble Nebula (NGC7635) & M52I have managed to put the new kit to use already: after tuning the spacing for the CCD camera, I managed to take a lot of sub-frames of the Bubble Nebula (NGC 7635) and M52. The image shown is in H-Alpha (using the Astrodon 5nm filter) and consists of 7hrs total in 20min subframes (at -20C). 

The Bubble itself is a large  (~7 light year) void formed by the action of the fierce stellar wind from a hot, highly luminous Wolf-Rayet star. This star also causes excitation of the surrounding nebula, giving us the H-Alpha light we image here. M52 is the open cluster to the bottom right, with Czernik 43 the slightly looser open cluster to the right of the image. The nebulosity to the bottom left is part of the larger region SH2-158, and the smaller areas of nebulosity to the top centre-left of the frame is the not often referenced planetary nebula KjPn8 (though this is quite faint here and needs a bit more magnification, and a lot more data to pull out well!)

Field is centred at: 
RA: 23h 22m 29.0s
Dec: +61° 19′ 07.7″
Up is 0.71 degrees E of N
(plate-solve from nova.astrometry.net)