IC1318 - Butterfly Nebula (Part C)

Located in the Cygnus complex the Butterfly nebula (IC1318) is a single giant HII cloud bisected by a thick obscuring dust lane which gives the symmetry from which it popular names derives. The image shows just one wing of the butterfly designated IC1318 C which is approximately 50 light years across.  We are looking deep into the Orion arm of our galaxy in this direction at a distance of 5,000 light years.  The image was created by assigning the SII, Ha and OIII data respectively to Red, Green and Blue and then applying a colour map to differentiate the SII and OIII areas from the dominant hydrogen.

Right ascension: 20h 29m 06s | Declination: +39° 58' 00" | Distance: 5,000 Light Years
Field of view: 57 x 38 arcmin

Camera: SBIG ST-10XME
Telescope: William Optics Megrez 120 F/7.5
Guiding: Starlight Xpress Active Optics (SXV-AO-LF) unit
Filters: Astrodon Ha (3nm), OIII (3nm), SII (3nm)
Exposures: Ha 20 x 30 min; OIII 20 x 30 min; SII 20 x 30 min
Total exposure: 30 hours
Image composition: Colour Mapped Narrowband SII:Ha:OIII
Scale: 1.56 arcsec/pixel
Image acquired: over 16 nights between May-July 2013 from Bristol (UK)

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL, Photoshop CS4 (Hubble Palette Colour Mapping following method by Bob Franke)

The Tadpole Nebula in Ha - IC410

Emission nebula IC 410 in the constellation of Auriga imaged in the red visible part of the electromagnetic spectrum at the hydrogen-alpha spectral line (656nm). The image shows a cloud of glowing gas over 100 light years across sculpted by stellar winds and radiation from the embedded open star cluster. The cluster can be seen just below the prominent dark dust cloud near image centre. The popular name for the nebula derives from the two tadpole shaped features with their tails made up of relatively dense material steaming away from the nebula’s central region.  This is the first image acquired from Bristol observatory with Astrodon 3nm narrowband filters. Sub exposure time was increased to 20 minutes although this is still below the optimal sky limited exposure time for this site.

Right ascension: 05h 22m 44s | Declination: +33° 24' 45" | Distance: 12,000 Light Years
Field of view: 57 x 38 arcmin

Camera: SBIG ST-10XME
Telescope: William Optics Megrez 120 F/7.5
Guiding: Starlight Xpress Active Optics (SXV-AO-LF) unit
Filters: Astrodon Ha (3nm)
Exposures: Ha 18 x 20 min
Total exposure: 6 hours
Image composition: Monochrome Ha
Scale: 1.56 arcsec/pixel
Image acquired: 06/02/2013; 02/03/2013; 13/03/2013

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL; Photoshop CS4; Focus Magic, Silver Efex Pro 2

Active Optics guiding with SXVR-H9 monochrome camera

As of January 2013 I am now using a Starlight Xpress SXVR-H9 monochrome camera for guiding in conjunction with my Starlight Xpress Active Optics (AO) unit.  The H9 camera uses the same SX Universal driver in MaxIm DL as the Lodestar which enables selection and control of an AO unit.

The H9 camera uses the sensitive Sony ICX285AL Exview HAD CCD with square 6.45um pixels and an image format of 1392 x 1040 pixels.  Operating at bin x2 the SXVR-H9 has a plate scale of 2.96 arc sec (compared to 3.85 arc sec for the Lodestar) with a field-of-view that is almost twice the area of the Lodestar.  Results so far suggest the increased resolution and larger field-of-view offer tangible benefits both to guiding precision and guide star selection.  I am now able to find guide stars more easily in the sparse star fields around galaxies. 

Pelican Nebula Ionisation Front – IC5067

The Pelican Nebula is large, low-density cloud of partially ionised gas associated with the North America Nebula in the constellation Cygnus.  Light from young energetic stars is slowly transforming cold gas to hot and causing an ionisation front to advance outwards.  Within the advancing front areas of dense cold gas can be seen to resist ionisation and survive as long pillars of dust and gas.  Jets of hot gas ejected from the heads of some prominent pillars are also apparent in the image.

Right ascension: 20h 51m 17s | Declination: +44° 24' 13" | Distance: 2,000 Light Years
Field of view: 57 x 38 arcmin

Camera: SBIG ST-10XME
Telescope: William Optics Megrez 120 F/7.5
Guiding: Starlight Xpress Active Optics (SXV-AO-LF) unit
Filters: Baader Ha (7nm), OIII (8.5nm), SII (8nm)
Exposures: Ha 11 x 15 min; OIII 22 x 15 min; SII 30 x 15 min
Total exposure: 15.75 hours
Image composition: Colour Mapped Narrowband SII:Ha:OIII (Hubble Palette)
Scale: 1.56 arcsec/pixel
Image acquired: Over 10 nights in August through December 2012 from Bristol (UK)

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL (Fat Tail Deconvolution), Photoshop CS4

Emission nebula in Cassiopeia - IC1795

Glowing gas and obscuring dust of the emission nebula IC1795 – part of the Heart Nebula (NGC896) – located in a complex of star forming regions at the edge of the large molecular cloud in the constellation Cassiopeia.  The colours in the image were created using the Hubble palette which maps emission from oxygen, hydrogen, and sulphur atoms to blue, green and red.

Right ascension: 2h 26m 50.8s | Declination: +62° 00' 48.2" | Distance: 6,000 Light Years
Field of view: 57 x 38 arcmin

Camera: SBIG ST-10XME
Telescope: William Optics Megrez 120 F/7.5
Guiding: Starlight Xpress Active Optics (SXV-AO-LF) unit
Filters: Baader Ha (7nm), OIII (8.5nm), SII (8nm)
Exposures: Ha 20 x 15 min; OIII 24 x 15 min; SII 26 x 15 min
Total exposure: 17.5 hours
Image composition: Colour Mapped Narrowband Ha:SII:Ha:OIII
Scale: 1.56 arcsec/pixel
Image acquired: 5, 6, 10 & 14 November 2012 from Bristol (UK)

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL (Fat Tail Deconvolution, DDP), Photoshop CS4

Cygnus Wall - NGC7000

The Cygnus Wall in the southern part of the North American Nebula (NGC 7000). This is an ionisation front where UV light from hot young stars is transforming the cold gas of interstellar space into a ‘wall’ of ionised hydrogen. The Hα emission line is colour mapped onto yellow, gold and brown in the image.

Right ascension: 20h 58m 50s | Declination: +43° 36' 39" | Distance: 1,800 Light Years
Field of view: 57 x 38 arcmin

Camera: SBIG ST-10XME
Telescope: William Optics Megrez 120 F/7.5
Guiding: Starlight Xpress Active Optics (SXV-AO-LF) unit
Filters: Baader Ha (7nm), OIII (8.5nm), SII (8nm)
Exposures: Ha 12 x 10 min; OIII 24 x 10 min; SII 24 x 10min
Total exposure: 10 hours
Image composition: Colour Mapped Narrowband Ha:SII:Ha:OIII
Scale: 1.56 arcsec/pixel
Image acquired: July & August 2012 from Bristol (UK)

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL, Photoshop CS4

Dust Sculptures in the Rosette Nebula

This part of the Rosette Nebula also known as NGC 2237 contains sculpted globules of dark dust and gas that are slowly being eroded away by the energetic light and winds of nearby massive stars. I am waiting for the Rosette to become visible again over the winter months to capture SII and OIII emission line data.

Right ascension: 06h 31m 44s | Declination: +05° 08' 49" | Distance: 5,000 Light Years
Field of view: 57 x 38 arcmin

Camera: SBIG ST-10XME
Telescope: William Optics Megrez 120 F/7.5
Guiding: Starlight Xpress Active Optics (SXV-AO-LF) unit
Filters: Baader Ha (7nm)
Exposures: Ha 26 x 15 min
Total exposure: 6.5 hours
Image composition: Monochrome Ha
Scale: 1.56 arcsec/pixel
Image acquired: January 2012 from Bristol (UK)

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL (DDP, Fat Tail Deconvolution), Photoshop CS4.

SBIG ST-10XME with Active Optics guiding

In January 2012 I upgraded to an SBIG ST-10XME CCD camera and at the same time purchased a Starlight Xpress SXV-AO-LF active optics unit to improve guiding accuracy.

The ST-10XME has a quantum efficiency (QE) of over 85% between 560-665 nm which includes the Hα emission line at 656.3 nm. It is a no anti-blooming gate (NABG) sensor which accounts for its high QE but the negative side of this is that when a pixel saturates a bloom (or vertical streak) is produced in the resulting image. My rationale for choosing the ST-10XME was the additional sensitivity given high light pollution levels in central Bristol and my decision to operate the Megrez 120 at F/7.5 (900mm FL). I currently use the Wodaski MaxIm DL plug-in to de-bloom my images.

The SXV-AO-LF unit works very well under ACP control. ACP automates guide star selection which avoids the hot pixels in the Lodestar guider and optimises exposures to give short track times (< 0.5 seconds) and fast guide rates (≥ 4 Hz). It has transformed the performance of my EQ6 mount. I can now routinely achieve round stars (Roundness ≤ 0.05) and FWHM values ≤ 2 arc seconds under moderate to good seeing. During the galaxy season with sparse star fields I do sometimes revert to standard off-axis guiding when selecting a suitable guide star for the AO unit is sub-optimal.

Eastern Veil Nebula - NGC6992

This is the eastern part of a large but relatively faint supernova remnant in the constellation of Cygnus. The rope-like filamentary structures of the nebula are the visible remnants of the shock-wave from the supernova explosion that occurred some 5,000 to 8,000 years ago.

Right ascension: 20h 56m 59s | Declination: +31° 14' 54" | Distance: 1,470 Light Years
Field of view: 34 x 25 arcmin

Camera: Atik 314L+
Telescope: William Optics Megrez 120 F/7.5
Filters: Baader Ha (7nm), OIII (8.5nm)
Exposures: Ha 32 x 15 min; OIII 24 x 15 min
Total exposure: 14 hours
Image composition: RGB (Ha, OIII, OIII+20%Ha)
Scale: 1.48 arcsec/pixel
Image acquired: August & September 2011 from Bristol (UK)

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL, CCDStack2, Photoshop CS4

The heart of the Heart Nebula

The three bright stars are O and B type giants (20-100 times more massive than our sun) of the Melotte 15 open cluster.  Stellar winds and intense ultraviolet radiation from these massive stars has sculpted the twisted tree-like structure in the image from within the centre of the extremely large cloud of ionised hydrogen gas that makes up the Heart Nebula (IC 1805) located in the Persius spiral arm of our galaxy.

Right ascension: 02h 33m 50s | Declination: +61° 26' 03" | Distance: 7,500 Light Years

Field of view: 34 x 25 arcmin

Camera: Atik 314L+

Telescope: William Optics Megrez 120 F/7.5

Filters: Baader Ha (7nm), OIII (8.5nm), SII (8nm)

Exposures: Ha 28 x 10 min; OIII 44 x 10 min; SII 30 x 10 min

Total exposure: 17 hours

Image composition: LRGB (Ha, SII, Ha, OIII)

Scale: 1.48 arcsec/pixel

Image acquired: 24 & 25 Dec 2010; 8, 9, 18, 20 & 28 Jan 2011 from Bristol (UK)

Image capture and guiding with MaxIm DL; Image processed with MaxIm DL, AIP4Win, Photoshop CS4

Filaments of dust and Bok globules in the Rosette Nebula

Dark filaments of dust radiating towards the centre of the Rosette nebula (NGC 2244).  The twisted helical pattern of these filaments is thought to be moulded by the interplay of stellar winds, radiation and electromagnetic forces emanating from the central cluster of hot young stars.  This is my favourite part of the Rosette - I particularly like the way the filaments of dust take on animal-like forms.

Right ascension: 06h 31m 44s | Declination: +05° 08' 49" | Distance: 5,000 Light Years

Field of view: 34 x 25 arcmin

Camera: Atik 314L+

Telescope: William Optics Megrez 120 F/7.5

Filters: Baader Ha (7nm), OIII (8.5nm), SII (8nm)

Exposures: Ha 15 x 10 min; OIII and SII each 6 x 5 min binned 2x2

Total exposure: 3.5 hours

Image composition: LRGB (Ha, SII, Ha, OIII)

Scale: 1.48 arcsec/pixel

Image acquired: 16/12/10 & 24/01/11 from Bristol (UK)

Image capture and guiding with MaxIm DL; Image processed with MaxIm DL, CCDSharp, Photoshop CS4

Imaging | Guiding | Focusing

This was the setup for my imaging train during 2010-2011.

The imaging camera is the Atik 314L+.  The camera is based on the sensitive Sony ExView ICX285AL sensor with a 1392x1040 CCD array of 6.45µm pixels.  It has full set point temperature regulation (cooling to - 27°C below ambient) enabling the creation of matched dark frame sets for calibration.  Image acquisition is controlled by MaxIm DL.

I use an off-axis guider for guiding long exposures which are typically of 10-15 minutes duration.  The photograph shows the Telescope Service low profile off-axis guider with the Starlight Xpress Lodestar autoguider attached.  The Lodestar is based on the Sony ICX429AL sensor with 8.2µm x 8.4µm pixels.  It is incredibly sensitive and never fails to offer a choice of guide stars even though I often use 0.5 second exposures during guiding.  Guiding is performed under MaxIm DL control and I use pulse guiding to send autoguiding commands to the telescope.

The dual speed Crayford focuser on the Megrez 120 has been modified with a motorised focusing system from LakeSide Astro.  It comprises an ASCOM compliant control unit and a stepper motor assembly which is controlled using FocusMax linked to MaxIm DL.  Autofocusing with Focus Max is fast and extremely accurate and is the key to obtaining sharp and detailed high-resolution images.

Elephant's Trunk Nebula - IC1396A

The Elephant's Trunk nebula is a dark and dense globule of interstellar gas and dust in the star cluster IC 1396 – an ionised gas region located in the constellation Cepheus about 2,400 light years away from Earth.

Right ascension: 21h 34m 38s | Declination: +57° 26' 325" | Distance: 2,400 Light Years
Field of view: 38.1 x 28.5 arcmin

Camera: Atik 314L+
Telescope: GSO 200 8” F/4 Newtonian Astrograph
Guiding: Telescope Service OAG with Starlight Xpress Lodestar guider
Filters: Baader Ha (7nm), OIII (8.5nm), SII (8nm)
Exposures: Ha 30 x 6 min; OIII 21x 6 min; SII 10 x 6min
Total exposure: 6 hours
Image composition: Colour Mapped Narrowband Ha:SII:Ha:OIII
Scale: 1.64 arcsec/pixel
Image acquired: July & August 2010 from Bristol (UK)

Image capture with MaxIm DL, FocusMax; Image processed with MaxIm DL, Photoshop CS4

William Optics Megrez 120 APO F/7.5

This is my primary telescope - a William Optics Megrez 120mm F/7.5 APO refractor. It uses a very high quality Japanese Ohara FPL-53 fluorite glass doublet lens with excellent colour correction. This is the latest version with an upgraded focuser steel base plate for improved performance under heavy load. It is mounted on a Skywatcher EQ6 mount under EQMOD / ACP control.

I choose to operate the telescope at its native focal length of 900 mm which gives me an image plate scale of 1.5 arcseconds with my Atik 314L+ and SBIG ST10-XME CCD cameras.