Category Archives: Galaxy

Starry Messenger

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The first galaxies were identified in the 17th Century by the French astronomer Charles Messier, although at the time he did not know what they were.  It was only when in 1924 American astronomer Edwin Hubble measured the distance to the Andromeda galaxy using cepheid variables, that the existence of other galaxies was finally established.  One hundred years on it’s now estimated that there are between 200 billion and 2 trillion galaxies in the Universe; as Douglas Adams said in the Hitchhikers Guide to the Galaxy, “Space…….is really big”! 

For astronomers this time of the year is generally referred to the ‘Galaxy Season’, as our view of the Milky Way from Earth changes from the winter sky of the Orion Spur and Perseus Arm to the summer view with Cygnus overhead down to Sagittarius in the south, in between we’re looking into deep space.  With very few exceptions, galaxies are located very far from Earth, which from our perspective makes them small and therefore a challenge for my imaging equipment.  However, this Spring I’ve been imaging the spectacular Leo Galaxy Cluster, a mere 330 million light-years from Earth (see cropped version of cluster at the top of the page).

Containing at least 70 major galaxies, the Leo Cluster unusually consists mostly of spiral galaxies, which are best seen here cropped from the original widefield image.  The bright elliptical galaxy near the centre of the image, NGC 3842, has one of the largest known black holes in the universe, which is about 10 billion times more massive than our sun! 

We have come a long way since Galileo Galilei published his astronomical treatise Sidereus Nuncius AKA Starry Messenger in 1610, the first scientific publication based on observations made through a telescope. Galileo’s work completely changed the way humanity understood the night sky and, by extension, our place in space, later leading to the acceptance of the heliocentric model of the planets.  Profound as that was, our understanding of the Universe since 1924 has even greater implications.  Moreover, the ability for an amateur to image something like the Leo Cluster from my back garden is exciting and very rewarding (see widefield version above + image location + orientation where the red dot = top left of image).        

 IMAGING DETAILS
ObjectLeo Galaxy Cluster
ConstellationLeo
Distance330 million light-years
Size Various
Apparent MagnitudeVarious
  
Scope William Optics GT81 + Focal Reducer FL 382mm  f4.72
MountSW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
GuidingWilliam Optics 50mm guide scope
 + Starlight Xpress Lodestar X2 camera & PHD2 guiding
CameraZWO ASI294MM CMOS sensor
 FOV 2.87o x 1.96o Resolution 2.50”/pix  Max. image size 4,144 x 2,822 pix   
EFWZWOx8 EFW & 31mm LRGB filters 
Capture & ProcessingAstro Photography Tool (APT), Deep Sky Stacker & PixInsight v1.8.9-2  
Image Location              & OrientationCentre = RA 11:44:12.40      DEC +19:50:25.70                         Right = North     
ExposuresL x30 + R x31 + G x31 + B x 31 @ 180 sec Total Integration Time: 6hr 9min     
 @ Gain 120 & 30 Offset 21 @ -15oC    
Calibration10 x 180 sec Darks + 10 x BB Flats & Dark Flats         @ ADU 32,000
Location & DarknessFairvale Observatory – Redhill – Surrey – UK        Typically Bortle 5-6
Date & Time7th + 9th + 14th April 2024 @ +21.30h  
WeatherApprox. <9oC   RH >=65%                  🌙 >=0% New Moon Waxing

2023 The Year In Pictures

by in Broadband, Dark Nebula, Deep Sky Objects, Equipment, Galaxy, General Astronomy, Globular Cluster, Imaging, Mosaic, Narrowband, Nebula, Other, Planetary Nebula, Processing, Samyang 135, Supernova, Widefield Imaging and tagged , , , | Leave a comment

This Christmas marks the 10th edition of my astrophotography calendar, consisting of my better images from the previous 12-months, which I produce for myself and members of the family.  Wow doesn’t time fly? Based on these images, I also compile a video of the images set to music, which we all watch together before seeing the actual calendar.  It’s become something of an occasion and is a great way to present the images, which look wonderful on today’s smart TV’s and is fun to watch and share with the family.

THE CALENDAR

Much longer imaging times (total of more than 145 hours), re-imaging old favourites in new ways and unusual, overlooked, or difficult objects, resulted in a very good 2023 astrophotography year and perhaps the best calendar yet?  The calendar for 2024 on YouTube can be viewed by clicking HERE and below is a brief overview of each image.  More detailed background information and imaging details for those interested can be found in relevant blogs I posted on this website.  The background music is the track Appleshine from Underworld’s album Drift.

 COVERSH2-284: Close-up of April’s image – along the inside of the ring structure are many dark dust pillars and globules, which on the right seem to resemble a hand with a bony finger pointing inwards!  
JANUARYNGC 1333: Nestled within the western area of the Perseus Molecular Cloud, some 1,100 light-years from Earth is the colourful NGC 1333 reflection nebula, one of the closest and most active star-forming regions of the night-sky.  
FEBRUARY  Spaghetti Nebula: Straddling the boundary of Taurus and Auriga constellations, is the giant supernova remnant (SNR) Simeis-147.  The stellar explosion occurred 40,000 years ago, leaving a rapidly spinning neutron star or pulsar at the core of the now complex and the expanding SNR.  
MARCHAurora Borealis: Situated just below the Arctic Circle, Iceland is well known both for its geology and views of the Aurora Borealis, which we saw in March on the south coast near Kirkjubaejarkklaustur.  
APRILSH2-284: A star-forming region of dust and gases, sculpted by radiation and interstellar winds emanating from a young (3 to 4 million years) star cluster located near the centre.       
MAYM3 Globular Cluster*: Consisting of 500,000 stars and over 11 billion years old, M3 is one of150 globular clusters that orbit around the Milky Way Galaxy.  
JUNEM27 Apple Core Nebula*: A planetary nebula, consisting of a glowing shell of ionized gas ejected from a red giant star in its late stage of life to become a white dwarf. Complex hydrogen (red) and oxygen (blue) fans form around the outer regions, with a pulsar-like beam transecting the nebula.  
JULYMonkey Head Nebula: Located 6,400 light years from Earth in the Orion constellation, the ‘Monkey’ is a so-called emission nebula, where new stars are being created within at a rapid rate.  
AUGUSTSH2-115: This widefield image contains a richness of various emission nebulae, centred around the distinctive large blue SH2-115 region.  Just to the left of SH2-115 is the small but enigmatic SH2-116 a faint, blue disc thought to be a planetary nebula.    
SEPTEMBERLDN-768 Black Cat Nebula: Close to M27 in the constellation of Vulpecula (“Little Fox”), is a dense region of stars broken-up by dark nebulae to create intriguing shapes. Here strung out from left-to-right, several of the dark nebulae seem to coalesce (visually) to create the form of a black cat.
OCTOBERSH2-126 Great Lacerta Nebula: On the western edge of the Milky Way in the southern part of Lacerta, is the very large but faint emission nebula SH2-126.  The red filament structures stretch over 3 degrees, to the right is the Gecko Nebula, a molecular cloud associated with bright young stars.
NOVEMBERFlaming Star & Tadpoles Nebula: Two emission nebulae: dust & gas of the Flaming Star (below) combined with red ionized hydrogen gas produces a flame affect. Above, the stellar winds and radiation pressure from hot massive stars creates the Tadpoles ‘wriggling’ away from the centre.
DECEMBERM51 Whirlpool Galaxy*: As the smaller galaxy passes behind M51, joint gravitational forces are interacting, resulting in the misalignment of stars and unusually bright blue and pink areas across the Whirlpool galaxy. Their fates are inextricably linked and might eventually merge.
                 Footnote: All images taken from Redhill, Surrey or telescope at a dark sky site in
          New Mexico, USA shown by an asterisk*
HAPPY NEW YEAR + CLEAR SKIES FOR 2024

Glactic Waltz

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The size and diversity of the cosmos produces many wonderful features, of which M51 the Whirlpool Galaxy ranks highly amongst astrophotographers and is certainly one of my favourites.  Unfortunately, it is at the limit for my equipment and location, though in 2020 I was fortunate to capture over 16-hours integration time and a reasonable image (see here).  Whilst currently in the summer doldrums of limited darkness, I chose to process M51 data previously obtained using a Takahashi FSQ 106 located at Deep Sky West in New Mexico, USA.

Seen face-on from Earth, the balanced arms of this grand design galaxy contains dark dust lanes, blue star clusters and numerous pink star-forming regions rich in hydrogen gas.  But it is the cosmic dance taking place between M51 and its companion dwarf galaxy NGC 5195 that makes this such an exciting and popular object.

The most popular theory of what’s happening, is that the smaller galaxy is passing behind M51 and the joint gravitational forces are interacting between the two, resulting in the misalignment of stars and unusually bright blue and pink areas across the M51 galaxy.  Though not certain, it seems that their fates are inextricably linked and might eventually merge.  Whatever the process taking place, it will take millions of years if not longer to play out and is likely to provide this exciting spectacle for many generations of astrophotographers yet to come!

Whilst I was satisfied with my image obtained here in Surrey at Fairvale Observatory in 2020, there’s no denying that the data set from New Mexico is in a different league and was a pleasure to process.  Given the short focal length of both telescopes, Takahashi FSQ 106 (530mm f5) and William Optics GT 81 (382mm f4.72), out of the camera both set-ups inevitably produce a wide FOV but nonetheless pleasing images (see image above).  However, the quality of the DSW data holds up much better when cropping out M51 and its dance partner, thus showing off the aforesaid details of this dynamic and colourful scene to great effect (see top of page).   

    

 IMAGING DETAILS
ObjectM51 Whirlpool Galaxy & NGC 5195
ConstellationCanes Venatici
Distance23 million light-years
Size Approx. 77,000 light-years (M51 only) ~10 arc minutes
Apparent Magnitude-+8.4
  
Scope Takahashi FSQ 106  FL 530mm  f/5  +  Moonlight Nightcrawler focuser  
MountParamount MyT
GuidingYes
CameraQSI 683-WSG8    KAF-8300 full frame CCD sensor   5.4nm pixels  
 FOV 1.94o x 1.46o   Resolution 2.1”/pix.   Image array 3326 x 2,507 pix   
ProcessingDeep Sky Stacker, PixInsight v1.8.9-1
Image Location              & OrientationCentre – RA 13:29:55.31      DEC +47:11:41.608 Top Left = North                   
ExposuresL x 16, R x 18, G x 16, B x 17 @ 900 sec & -20o C Total Integration Time: 16hr 45min     
Calibration48 x 900 secs Darks   x47 Bias & x20 LRGB Flats   
Location & DarknessDeep Sky West – amateur hosting facility near Rowe, New Mexico  – USA    SQM Typically >= 21.7
Date & TimeJanuary 2018    

Feel The Space

by in Broadband, Deep Sky Objects, Equipment, Galaxy, General Astronomy, Imaging, Widefield Imaging and tagged , | Leave a comment

As our closest galactic neighbour, I’ve imaged M31 the Andromeda Galaxy five times since beginning my personal astrophotography journey in 2014, each time using my William Optics GT81 apo refractor – first with a DSLR, then a ASI1600mm-Cool and most recently ASI294MM cameras.  Andromeda is perhaps the perfect object for my equipment, as it just fits the field-of-view of the aforesaid set-up, which produces something of an up-close-and-personal image of this alluring galaxy. But despite the success of these images, perhaps there’s an alternative view?

This year, I therefore deployed my Samyang 135 + ASI1600MM-Cool rig to capture 6 ½ hours of Andromeda, the result of which shows a whole new perspective of M31.  The widefield format of this lens produces greater context than previous images, whilst still obtaining excellent details and colours of the galaxy itself.  As a result, this final image (see above) better reveals the galaxy in its true glory deep in space, which in some ways I believe can be more powerful than the more popular close-up renditions of this impressive object (M31 with star reduction applied to the image below).   

 IMAGING DETAILS
ObjectM31 Andromeda Galaxy
ConstellationAndromeda
Distance2.5 million light-years
Size  3.2o x 1o  or 220,000 light-years           
Apparent Magnitude+3.44  
  
Scope  / LensSamyang 135 @f2.8  
MountSW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding Sky-Watcher EvoGuide 50ED
 + Starlight Xpress Lodestar X2 camera & PHD2 guiding
CameraZWO1600MM-Cool mono  CMOS sensor
 FOV 7.5o x 5.67o Resolution 5.81”/pix  Max. Image Size 4,656 x 3,520 pix   
EFWZWOx8 EFW & 31mm ZWO LRGB & 7nm Narrowband filters 
Capture & ProcessingAstro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.8-12, Photoshop CC, Topaz Denoise
Image Location              & OrientationCentre:  RA 00:42:34.682      DEC +41:14:06.324                         Right = North   Top = East 
ExposuresL 75 x 60 sec, R 27x  G27x B22 x 180 sec, Ha 17 x 300 sec Total Integration Time: 6hr 28 min     
 @ 139 Gain   21  Offset @ -15oC    
CalibrationDarks, Flats & Flat Darks   
Location & DarknessFairvale Observatory – Redhill – Surrey – UK        Typically Bortle 5-6
Date & Time17th, 21st & 22nd November 2022  @ +20.00h  
WeatherApprox. <=5oC   RH >= 85%                  🌙 approx. New Moon

2021 The Year In Pictures

by in AstroBin, Broadband, Dark Nebula, Deep Sky Objects, Galaxy, General Astronomy, Globular Cluster, Imaging, Narrowband, Nebula, Processing, Star Cluster, Supernova, Widefield Imaging and tagged , | Leave a comment

Every year since 2014 I’ve published a retrospective blog of my astrophotgraphy year just ending called Reflections. It’s been a useful task that enables me to bring together the best and sometimes the worst of my images, in order to consider the good and bad points + progress made + set some objectives for the coming year. Eight years on, after which I believe I’ve now reached at least a respectable level of imaging and processing, I’ve decided to stop this format for the time being.

Notwithstanding, at this time of the year I also produce an astrophotography calendar for members of my family, which consists of the better images from the year just ending; I think they like them and certainly all use the calendar during the coming year. Moreover, I also recently started to compile a video of the said calendar images set to appropriate music, which we all watch together prior to seeing the actual calendar. It’s a great way to present the images, which look really stunning on today’s large Smart TV’s and is fun to watch with the family too.

The video for this last year 2021 can be viewed on YouTube HERE and below is a brief very general overview of each image. More detailed background information and imaging details for those interested can be found in relevant blogs posted on this site during the past year.

2022 CALENDAR

A new set of filters, improved processing techniques and access to data from a telescope at a dark sky site in New Mexico, USA (shown by an asterisk *) contributed to an exciting astrophotography year in 2021.                  

FRONT COVERThe Carnival of Animals: Special processing of the inner region of the Rosette Nebula highlights the ‘animals’ or Bok Globules – clouds of dust undergoing gravitational collapse as part of the process of new star formation.  
JANUARYLDN-1250 Dark Nebula*: Dark or absorption nebulae are a type of interstellar cloud which are so dense they obscure or absorb visible light emitted from objects behind or within and thereby contrast with the general light flux of the Universe as dark areas.  
FEBRUARYCTB-1 Supernova Remnant*: The overall structure of this supernova remnant is that of a circular shell, with a conspicuous rupture towards the north (lower right of image).  The main red Ha-shell is composed of multiple interlocking filament limbs, with a blue / green OIII arc along one side.  
MARCHJellyfish Nebula: Locatedin the Gemini constellation some 5,000 light years from Earth, this is a remnant of a supernova that took place during the past 30,000 years. With a diameter of 70 light-years, the object is visually speaking nearly twice the size of a full moon.     
APRILMarkarian’s Chain: The Virgo cluster consists of more than 2,000 galaxies, within which Markarian’s Chain forms a J-curve string of bright galaxies that share a common motion through space.    
MAYM13 Great Globular Cluster of Hercules*: Consisting of several hundred thousand stars and 145 light-years in diameter, M13 is considered to be the finest cluster in the Northern Hemisphere.  
JUNECave Nebula*: Located along the plane of the Milky Way is the diffuse emission nebula referred to as the Cave Nebula.  The Cave at the centre is critically located at the boundary of the Cepheus molecular cloud and the hot, young stars which ionize the surrounding gases to great effect.  
JULYOrion Widefield: Framed around the area of Orion’s Belt, the Horsehead Nebula and the Great Orion Nebula, look hard and the refection nebula M78 can also be seen in the lower left corner.    
AUGUSTElephant’s Trunk Nebula*: A very large emission nebula, the so-called Elephant’s Trunk Nebula is rightly viewed as one of astrophotography’s most iconic images. The ‘trunk’ itself dominates the centre of this image and is illuminated from behind by a bright star forming region.  
SEPTEMBERM31 Andromeda Galaxy: The full benefit of new filters, improved guiding, clear skies over 6-nights and extensive use of new processing techniques can be seen in my best image yet of Andromeda.      
OCTOBERButterfly Nebula: Situatedwithin the Orion Arm of the Milky Way is the Gamma Cygni nebula, a diffuse emission nebula surrounding the star Sadr.  Either side of the dark rift which divides the image from top to bottom are two large bright areas that together form the so-called Butterfly.  
NOVEMBERM33 Triangulum Galaxy: Like it’s neighbour Andromeda, better data and processing has produced an exciting new image of M33 this year, the red areas highlight Ha-rich star-forming regions  
DECEMBERFlying Bat & Giant Squid Nebula*: This very faint OIII emission nebula Ou4 required an imaging time of 40-hours.  For obvious reasons Ou4 has become known as the Giant Squid Nebula which, moreover, lies within the much larger SH2-129 HII emission region or the Flying Bat Nebula.     

HAPPY NEW YEAR + CLEAR SKIES IN 2022

Galactic Triplets

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After successfully imaging M31 the Andromeda galaxy at new moon in early October, I was lucky that the next moon cycle in early November also provided good conditions and it seemed appropriate to just shift attention to Andromeda’s closest neighbour, which at this time of the year occupies a favourable part of the eastern sky in the early evening.  Only 15o from M31, M33 AKA the Triangulum Galaxy is the third-largest member of the Local Group of galaxies after Andromeda and the Milky Way.  Although very faint, in very good dark night sky conditions M33 can apparently be viewed with the naked eye. Along with our own Milky Way, this group travels together in the universe, as they are gravitationally bound.

Andromeda is eight times brighter and nearly four times larger than Triangulum, which for various reasons I have previously found difficult to image, despite its relative proximity to us.  On this occasion I was therefore very pleased to obtain a good data set over three nights that included 3-hours of 10-minute Ha exposures.  The result is definitely my best image yet of this tricky but attractive target, which in particular highlights the numerous red star-forming regions that abound throughout the galaxy’s arms.  I’ll almost certainly be back again another day but for now I am at last satisfied with the result.

 IMAGING DETAILS
ObjectM33 Triangulum Galaxy
ConstellationTriangulum
DistanceApprox. 2.7 million light-years
Size71’ x 42’  ~ 60,000 light-years
Apparent Magnitude+5.72
  
Scope William Optics GT81 + Focal Reducer FL 382mm  f4.72
MountSW AZ-EQ6 GT + EQASCOM computer control
GuidingWilliam Optics 50mm guide scope
 + Starlight Xpress Lodestar X2 guide camera & PHD2 control
CameraZWO1600MM-Cool (mono)   CMOS sensor
 FOV 2.65o x 2.0o Resolution 2.05”/pix  Max. image size 4,656 x 3,520 pix   
EFWZWO x8 EFW & 31mm LRGB + 3nm Ha Chroma filters 
Capture & ProcessingAstro Photography Tool,  Deep Sky Stacker, PixInsight v 1.8.8-9, Photoshop CS3, Topaz Ai Denosie
Image Location              & OrientationCentre:  RA 01:33:53.6    DEC 30:39:18.9                      Top = North   Right = West  
Exposures15 x 300 sec LRGB + 18 x 600 sec Ha   Total time: 8 hours
 @ 139 Gain   21  Offset @ -20oC    
Calibration5 x 300 sec & 5 x 600 sec Darks  + 15 x LRGBHa Flats & Dark Flats @ ADU 25,000  
Location & DarknessFairvale Observatory – Redhill – Surrey – UK        Typically Bortle 5
Date & Time2nd 3rd 4th November 2021 @ +19.00h  
WeatherApprox. <6oC   RH = >=80%      New Moon

The Journey

by in Deep Sky Objects, Galaxy, General Astronomy, Imaging, Narrowband, Processing, Universe and tagged | Leave a comment

A year after taking up astronomy as a hobby, at the behest of my elder daughter I started this blog in 2014.  Describing the objective and content of the blog I adopted the strapline “A personal discovery of the Universe through astronomy and astrophotography”, which could also be described as a journey.  In reality it’s been an adventure consisting of two threads: the knowledge and related science of astronomy and the challenge of astrophotography.   As we on Earth pass through space whilst at the same time rotating 360o each year around the sun our view of the night sky changes month-by-month, inevitably returning to the same perspective each 365-days.  Against this background I therefore often return to certain objects every few years hopefully armed with new astrophotography skills in pursuit of an even better image.

Following such a path I’ve already imaged M31 the Andromeda Galaxy on four separate occasions since 2015, each time enthralled by the majesty and beauty of this barred spiral galaxy.  Notwithstanding, it was clear to me that there was significant scope for improvement of the previous images with both better data and processing. Since the last attempt in October 2019 a myriad of positive developments have taken place of which perhaps three stand out: multi-star guiding, the purchase of Chroma filters and in particular the use of PixInsight image for processing – all have been game changers, so much so that reprocessing that image now also looks good – see below.

 However, whilst the said progress has already been transformative to my astrophotography during the past year, inevitabky it is imaging conditions that play the most critical role, especially in England.   Fortunately during this autumn in both October and November for once the new moon coincided with clear skies, providing no less than six nights over which I was able to obtain almost 12-hours of some of perhaps my best ever data.  Based on this I’ve been careful to apply my best new processing skills and am thankful that the final HaLRGB image has turned out very well.  In particular, the dust lanes stand out against the bright core and surrounding blue intergalactic dust and gases, which are themselves punctuated by the bright red regions rich in Ha light. 

In the blogs that accompanied previous Andromeda images I’ve often referred to the galaxy as a neighbour of the Milky Way but really we are part of the same family known as the Local Group.  Some 10-million light years in diameter, more than 30 galaxies form two collections around the two largest galaxies of Andromeda and the Milky Way.  Gravitational forces play the central role in controlling this group, especially Andromeda which is itself moving towards the Milky Way at about 70 miles per second and is destined to merge in about +/- 4 billion years; recent studies indicate that an outer halo of stars extending up to 2-billion light years from Andromeda may be in the influence of the galaxy, suggesting this event may already have started!

Thereby my personal journey of astrophotography is set to continue somewhat in parallel with that of Andromeda, which will I am sure lead to further hopefully even better images of this exciting deep sky object that is perfect for my equipment – after all we’re getting closer at the rate of 2,207,520,000 miles each year!                     

 IMAGING DETAILS
ObjectM31 the Andromeda Galaxy.
ConstellationAndromeda
Distance2.5 million light-years
Size3.2o  x 1o  or 220,000  light-years  
Apparent Magnitude+3.44
  
Scope William Optics GT81 + Focal Reducer FL 382mm  f4.72
MountSW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
GuidingWilliam Optics 50mm guide scope
 + Starlight Xpress Lodestar X2 guide camera & PHD2 guiding
CameraZWO1600M M-Cool mono  CMOS sensor
 FOV 2.65o x 2.0o Resolution 2.05”/pix  Max. image size 4,656 x 3,520 pix   
EFWZWO x8 EFW + Chroma LRGB & Ha OIII SII 3nm filters 
Capture & ProcessingAstro Photography Tool , Deep Sky Stacker, PixInsight 1.8.8-8, Photoshop CS3 & Topaz AI Denoise
Image Location              & OrientationOriginal image centre  RA 00:42:48      DEC 41:15:05                      Final image rotated 180o  i.e. Bottom = North + 5% crop
ExposuresL 71 x 60 sec  R17  G 20  B  27 x 300 sec  Ha 35 x 600 sec Total time: 11hr 46 minutes   
 @ 139 Gain   21  Offset @ -20oC    
CalibrationDarks 5 x 600 sec + 5 x 300 sec + 60 x 60 sec HaLRGB Flats & Dark Flats  x15 each    @ ADU 25,000
Location & DarknessFairvale Observatory – Redhill – Surrey – UK        Typically Bortle 5-6
Date & Time1st 5th 6th 8th 9th  October & 4th November 2021 @ +/-19.00h  
WeatherApprox. 14o to 5oC   RH >=65% to +85%             🌙 New Moon

Galactic Grotto

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Located along the plane of the Milky Way in the Cepheus constellation is the diffuse emission nebula Sh2-155, commonly referred to as the Cave Nebula.  This widefield view shows the so-called Cave at centre of the image, critically located at the boundary of the massive Cepheus molecular cloud and the hot, young stars of the Cepheus OB-3 association which ionize the surrounding gases to great effect. 

Location of the Cave Nebula

Overall the features are very faint and even with a total integration time of nearly 40-hours for the full data-set the Cave is difficult to capture and process using the Hubble SHO palette but nonetheless has resulted in a striking final image (see top-of-the-page).  An alternative bicolour HOO cropped version (see below) perhaps shows the details of Cave itself better?

 IMAGING DETAILS
ObjectSH2-155 Cave Nebula  AKA Caldwell 9
ConstellationCepheus
Distance2,400  light-years
Size 50 x 30 arc minutes  ~70.0 light-years;  Cave Nebula ~10.0 light- years  
Apparent Magnitude+7.7
  
Scope Takahashi FSQ 106  FL 530mm  f/5  +  Moonlight Nightcrawler focuser  
MountParamount MyT
GuidingYes
CameraQSI 683-WSG8    KAF-8300 full frame CCD sensor   5.4nm pixels  
 FOV 1.94o x 1.46o   Resolution 2.1”/pix.   Image array 3326 x 2,507 pix   
ProcessingDeep Sky Stacker,  PixInsight v1.8.8-7,  Photoshop CS3, Topaz Denoise
Image Location              Centre  –  RA 22:57:37.145      DEC +62:32:54.296                      
Exposures20 Ha  30 OIII  29 SII x 1,800 secs  @ -20C Total Integration Time: 39hr 30min     
Calibration24 x 1,800 secs Darks   x200 Bias  &  x32  Flat Darks  
Location & DarknessDeep Sky West – amateur hosting facility near Rowe, New Mexico  – USA    SQM Typically >= 21.7
Date & TimeQ3  2018    

Galactic Stepping Stones

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The Virgo Cluster consists of more than 2,000 galaxies, which unfortunately are optically too much for my small William Optics GT81 telescope individually.  However, one of several sub-groups within the Virgo Cluster forms a striking J-curve shape that does make for a pleasing LRGB image.  Discovered and named after the Armenian astrophysicist Benjamin Markarian, Markarian’s Chain is a string of bright galaxies that share a common motion through space.  I first imaged the Chain in April 2015 using a modded DSLR and then again in April 2017, as my first LRGB image with the then new ZWO ASI1600MM-Cool camera but with integration times of less than 1-hour on both occasions, the resulting images were far from ideal.  On this occasion using my new Chroma LRGB filters for the first time I was determined to do better.

The new filters and nearly 7-hours integration time has resulted in a much more dynamic and detailed image, which I believe now does justice to this spectacular group of galaxies.  Analysis of the image using Astrometry.net shows just how crowded this area of Virgo is with galaxies (see annotated image above) but it is Markarian’s Chain that inevitably stands out together with a few other adjacent galaxies.

  • Large 10th magnitude M84 & M86 galaxies at the western end of the Chain dominate the image.  M84 is the object with the highest blue shift in the Messier catalogue, which is a result of its rapid movement (244km/sec) towards the centre of the Virgo Cluster and us.  At the centre of M84 is a 1.5 billion solar mass black hole.
  • NGC 4420 & NGC 4388 – by comparison these edge-on galaxies together with even smaller NGC 4413 & NGC 4425 seem to frame the larger M84 and M86.   
  • Next along the Chain is a pair of interacting galaxies, the smaller round shaped NGC 4435 and NGC 4438 with its distorted disk, known as “The Eyes”.                             
  • As the Chain starts to turn, some 20’ along is NGC 4458 and its partner, the 11th magnitude elliptical NGC 4461.
  • The final section of the Chain consists first of NGC 4473, its brightness generated by a supermassive black hole – at 100 million solar masses its diameter of 4.46au which would stretch from the Sun to the asteroid belt!  Thereafter the 11.4 magnitude barred lenticular galaxy NGC 4477 defines the north eastern extremity of Markarian’s Chain.
  • As previously noted, there are many other galaxies in this part of the Virgo Cluster.  Perhaps most notable though is M87, from which the first ever image of a black hole was the obtained in 2019 – consisting of some 6.5 billion solar masses.

             

All-in-all Markarian’s Chain makes for a rewarding image using my small telescope combined with the new Chroma filters.  Such is the nature of the image the galaxies might also suggest a string of pearls or perhaps galactic stepping stones – metaphorically leading to the next phase of my astroimaging journey.

 IMAGING DETAILS
ObjectMarkarian’s Chain
ConstellationVirgo & Coma Berenices
Distance50 – 55 million light-years
Size  ~2.5o total
Apparent MagnitudeVaries +10 to +12 approx.  
  
Scope William Optics GT81 + Focal Reducer FL 382mm  f4.72
MountSW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
GuidingWilliam Optics 50mm guide scope
 + Starlight Xpress Lodestar X2 camera & PHD2 guiding
CameraZWO1600MM-Cool mono  CMOS sensor
 FOV 2.65o x 2.0o Resolution 2.05”/pix  Max. image size 4,656 x 3,520 pix   
EFWZWOx8 EFW & 31mm Chroma LRGB filters 
Capture & ProcessingAstro Photography Tool + PHD2 +  Deep Sky Stacker, PixInsight v1.8.8-7, Photoshop CS3, Topaz Denoise
Image Location &           OrientationCentre  RA 12:27:46.65      DEC +13:03:06.44  @21.30h                      Left = North     
Exposures100 x 60 sec L , 54 x 60 sec R,  55 x 60 sec G&B Total Integration Time: 6hr 44 min     
 @ 139 Gain   21  Offset @ -20oC    
Calibration10 x 60 sec Darks  15 x  LRGB Flats & Dark Flats         @ ADU 25,000
Location & DarknessFairvale Observatory – Redhill – Surrey – UK        Typically Bortle 5-6
Date & Time5th & 6th April 2021  @ +21.00h  
WeatherApprox. <2oC   RH >=45%                  🌙 30% waning

Galactic Bloom

by in Deep Sky Objects, Galaxy, General Astronomy, Narrowband, Universe and tagged , , | 2 Comments

 

M63 HaLRGB FinalCropRotate3 (Large)-denoise-denoise

You don’t have to be an astronomer to appreciate Van Gogh’s wonderful evocation of the night sky in his 1889 painting Starry Night.  He knew a thing or two about sunflowers too and I’ve often stopped by the National Gallery in Trafalgar Square to take a peep at his famous painting of them.  However, it was still more than thirty years after completing these paintings that we first learned that such features as galaxies and the rest of the Universe even existed beyond our own Milky Way.  Since then our knowledge of the cosmos has expanded considerably and today provides no end of imaging opportunities for the astrophotographer, subject to clear skies!

Having started the galaxy season with M106 and, given the excellent conditions that prevailed throughout much of Spring this year, I chose to return to the same area of the sky again to image M63, AKA the Sunflower Galaxy.  M63 has a spiral form but with no apparent central bar and in visible light lacks large scale spiral structure, although two-arm structures are noticeable in near infra-red.  Instead the dust lanes are extensively disrupted producing a patchy appearance and is thus classified as a flocculent galaxy – in this case looking something like a sunflower.

As previously discussed, most galaxies are a real challenge for my equipment but an earlier experiment indicated it might just be possible to image M63, the trick would be obtaining sufficient integration time.  Fortunately three clear nights approaching a new moon in April provided over 8-hours of good subs, which I’m pleased to say resulted in a decent final image after all.  The background sky is less busy than I would wish but there’s nice colour in the stars and also a few very small faint fuzzies on close inspection.  Notwithstanding,  M63 is clearly the star of the show (no pun intended) with the so-called flocculation clearly evident and numerous random dust lanes criss-crossing the entire galactic disc.

Although in 1924 Edwin Hubble’s recognition that galaxies, such as our own, existed outside the Milky Way, M63 was discovered by Pierre Méchain and catalogued by Charles Messier in 1779, long before Van Gogh’s paintings.  He might conceivably have known of its presence therefore but not what it was and would surely be inspired to see and know about the Sunflower Galaxy as we do today.

IMAGING DETAILS
Object M63, NGC 5055 AKA Sunflower Galaxy
Constellation Canes Venatici
Distance 29 million light-years
Size 12.6’ x 7.2’
Apparent Magnitude +9.3
 
Scope  William Optics GT81 + Focal Reducer FL 382mm  f4.72
Mount SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding William Optics 50mm guide scope
  + Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera ZWO1600MM-Cool mono  CMOS sensor
  FOV 2.65o x 2.0o Resolution 2.05”/pix  Max. image size 4,656 x 3,520 pix   
EFW ZWOx8 + ZWO LRGB & Ha OIII SII 7nm filters 
Capture & Processing Astro Photography Tool + PHD2 +  Deep Sky Stacker & Photoshop CS3
Image Location              & Orientation Centre  RA 13h 15m 49.47”      DEC +42o 01’ 45.62”                     

Top = North approx..     
Exposures 30 x L  17 x R  18 x G  23 x B  12 x Ha x 300 sec

Total Time:  8hr 20 min    
  @ 139 Gain   21  Offset @ -20oC    
Calibration 5 x 300 sec Ha + 10 X 300’ RGB  Darks,  20 x 1/4000 sec Bias  10 x  HaRGB Flats               @ ADU 25,000
Location & Darkness Fairvale Observatory – Redhill – Surrey – UK        Typically Bortle 5-6
Date & Time 14th 15th & 16th April 2020  @ +22.00h  
Weather Approx. <=8oC   RH 60 – 70%                  🌙 40% waning