IC1396 – Large emission nebula in Cepheus

IC1396v3IC 1396 is a large and comparatively faint emission nebula and star forming region over 100 light-years across in the constellation Cepheus. It is energised by the bright central triple star system called HD 206267. All three components are massive stars and the intense ultraviolet radiation they give off ionizes the gas of IC 1396 causing compression of the denser globules of the nebula leading to star formation. Among the intriguing dark shapes within IC 1396 is the dense globule of gas and dust known as the Elephant’s Trunk nebula (IC 1396A) located in the upper central part of the image. The image shows emission in the Hydrogen Alpha (Ha) line at 656nm.

This is a first light image from my new wide field imaging system based on the Telescope Service Photoline TS60ED refractor. This has a 60mm apochromatic doublet lens with a FPL53 element by Ohara (Japan). I am using the TS Photoline 4-element 2 inch 0.79x reducer to decrease the focal length from 330mm to 260mm which increases the focal ratio from F/5.5 to an impressive F/4.4 for imaging.

Right ascension: 21h 39m 55.3s | Declination: +57° 36′ 48.8″ | Distance: 2,400 Light Years
Field of view: 234 x 176 arcmin

Camera: QSI 583wsg
Optics: TS Photoline TS60ED F/4.4 APO
Guiding: Off-axis with Lodestar guider
Filters: Baader Ha (7nm)
Exposures: Ha 6 x 20 min
Total exposure: 2 hours
Image composition: Monochrome Ha
Scale: 4.2 arcsec/pixel
Image acquired: 17th July 2015

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL and Photoshop CC 2014 [Astronomy Tools v1.6; HDR Toning]

Elephant’s Trunk Nebula in IC1396

IC1396-ST10-v3.4sThe Elephant’s Trunk nebula is a concentration of interstellar gas and dust within the larger emission nebula IC 1396 located in the constellation Cepheus about 2,400 light years away from Earth. The image shows the dense globule IC 1396A commonly known as the Elephant’s Trunk nebula because of its appearance as a sinuous dark cloud at visible light wavelengths. The bright edge of the cloud is where its surface is being illuminated and ionised by the very bright and massive nearby triple star system HD 206267A.

I acquired the image while testing the Starlight Xpress active optics unit which hopefully will enable me to increase sub-exposures to 30 minutes while operating the APM 152-1200ED telescope at its native focal length of 1,200 mm. Note that the data were acquired under astronomical twilight and first quarter / full moon in June which is a testament to narrowband imaging and Astrodon filters in particular.

Right ascension: 21h 35m 33s | Declination: +57° 25′ 52″ | Distance: 2,400 Light Years
Field of view: 42 x 28 arcmin
Camera: SBIG ST-10XME
Telescope: APM 152-1200ED F/7.9
Guiding: Starlight Xpress Active Optics SXV-LF-AO
Filters: Astrodon Ha (3nm), OIII (3nm)
Exposures: Ha 9 x 20 min, OIII 15 x 20 min
Total exposure: 8 hours
Image composition: Cannistra Modified Bicolour Narrowband Technique
Scale: 1.15 arcsec/pixel
Image acquired: June 2015

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

Wide field deep sky astrophotography using camera lenses

QSI583-Pentax67-300-rig

My experiments using camera lenses for wide field deep sky astrophotography are coming to a close. I am not satisfied with the quality of images acquired. The main issue I have found is that stopping down the lenses to overcome optical aberrations and obtain useable stars reduces clear aperture which significantly affects the ability of the lens to gather enough light for extended faint objects.

The wide field rig I have been using is shown above. It is based on a QSI 583wsg mono CCD with lens adapter for Pentax 6×7 medium format lenses. The rig uses standard ADM mounting hardware (dovetails and guide scope rings) and a custom bracket manufactured by Lakeside Astro to support their ASCOM compliant motorised focussing system. The stepper motor drives a timing belt which goes around the focus ring of the lens allowing automatic focussing during an imaging session. The rig worked well using my standard imaging software stack of MaxIm DL and FocusMax under ACP control. Good V-curves for focussing were obtained for different lenses and produced accurate and repeatable results.

Two vintage SMC Pentax 6×7 lenses were tested – a 165mm F/2.8 and a 300mm F/4. Mint condition 1980’s versions of these lenses were purchased second hand from Japan for around £100 each. To produce useable stars both lenses were stopped down by two stops from wide open. This significantly reduced clear aperture for the 300mm lens and coma was still present in the corners of images. Higher quality results were obtained using the 165mm lens. My conclusion is that for deep sky work it would be worth spending a bit more and purchasing a good quality short focal length apochromatic refractor with ED glass.

See Jerry Lodriguss (Catching the Light) for a good and balanced review of camera lenses for astrophotography. High quality camera lenses are well suited for landscape astrophotography and there are numerous articles on the web on choosing and using lens for Milky Way photography.

NGC2264 – Cone and Fox Fur Nebula

NGC2264-v1.3sNGC 2264 describes several objects in the constellation Monoceros lying about 2,700 light-years from Earth. One is the Christmas Tree star cluster nearby the blazing bright blue star S Monocerotis at centre right. The surrounding diffuse nebula is caused by H-alpha emissions from hydrogen gas stimulated by ultraviolet radiation emitted by S Monocertis and the cluster’s other blue stars. The nebula is well known for two special star forming regions. At centre left is the Cone Nebula named for its apparent shape and sculpted by fierce stellar winds. It is a dark molecular cloud within which other new stars are forming. Numerous other sculpted swirls of nebulosity are nearby. At lower right is the Fox Fur Nebula (Sharpless 273) named after its rich textured appearance also the result of sculpting by stellar winds. In contrast, the blue reflection nebula is caused by scattered blue light reflecting off residual dust in a region where stars have already formed.

This image is a bicolour combination of Ha and OIII images to create a synthetic green image displayed as an RGB composite with Ha luminance. PixInsight DBE (Dynamic Background Extraction) was used in the absence of suitable flat frames to remove sky background noise and gradients. Photoshop CC layers and layer mask processing techniques were used for colour and spatial enhancement – Levels, Curves, Reduce Noise, Selective Color, HDR toning, Smart Sharpen, Local Contrast Enhancement and Unsharp Mask in predominant use. Additional noise reduction (TGVDenoise) and local contrast enhancement (HDRMultiscaleTransform) was carried out in PixInsight.

Right ascension: 06h 41m 08s | Declination: +09° 41′ 15″ | Distance: 2,700 Light Years
Field of view: 54 x 37 arcmin

Camera: SBIG ST-10XME
Telescope: APM 152-1200ED F/6.2 with Riccardi x0.75 Reducer
Guiding: Off-axis with Lodestar guider
Filters: Astrodon Ha (3nm), OIII (3nm)
Exposures: Ha 8 x 20 min, OIII 11 x 20 min
Total exposure: 6.3 hours
Image composition: Cannistra Modified Bicolour Narrowband Technique
Scale: 1.49 arcsec/pixel
Image acquired: 8th, 9th & 16th February 2015

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL; Photoshop CC, PixInsight

Widefield view of the Rosette Nebulae in Ha – NGC2237

Rosette-Ha-v3c90This is a first light image from a SMC Pentax 67 300mm lens attached to my QSI583 wide-field imaging rig. The rig is housed in my relocated observatory situated in the Polden Hills of Somerset. The image is a monochrome hydrogen alpha (Ha) image of the Rosette Nebula located in the constellation of Monoceros. Arguably one of the finest HII regions in the northern sky the region is a very active area of star formation covering approximately 130 light years and containing some 10,000 solar masses of gas and dust.

As a vintage Pentax lens the SMC Pentax 67 1:4/300 is noted for its image quality and sharpness but is not popular with photographers because of its size and weight. However this is not an issue when it is mounted on an EQ6 equatorial mount for astrophotography. This lens is the 1987 variant recently purchased in mint condition from an eBay seller in Japan. I stopped the lens down to F/5.6 to improve image sharpness and to obtain good quality and repeatable V-curves for auto focussing. The resulting image is still a little soft and further experimentation is required to optimise auto focussing of the lens.

Right ascension: 6h 32m 46.0s | Declination: +4° 55′ 25″ | Distance: 5,000 Light Years
Field of view: 206 x 155 arcmin

Camera: QSI 583
Optics: SMC Pentax 6×7 300mm Lens F/4
Guiding: Off-axis with Lodestar guider
Filters: Baader Ha (7nm)
Exposures: Ha 25 x 20 min
Total exposure: 8.3 hours
Image composition: Monochrome Ha
Scale: 2.72 arcsec/pixel
Image acquired: January – February 2015

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL and Photoshop CS4 and HDR toning in Photoshop CC 2014.

Emission Nebula NGC6820 with Open Cluster NGC6823

NGC6823-v1

The open star cluster NGC 6823 lies at the centre of the image. It is about 50 light years across and about 6000 light years distant towards the constellation of Vulpecula (the Fox). The cluster is associated with the HII region Sharpless 86 and is embedded within the mixed emission and reflection cloud NGC 6820. Dispersed among the surrounding nebulosity are a host of dark clouds, elephant trunk like pillars and several striking dark globules of gas and dust known as Bok globules. The huge pillars of gas and dust are created by erosion from the hot radiation emitted from the brightest cluster stars. The Bok Globules represent collapsing protostellar cores of gas and dust that will ultimately evolve to form infant stars.

The image was created by mapping the SII, Ha and OIII data to RGB respectively and then adjusted using Photoshop’s Selective Colour tool. Final enhancements were performed using the Sharpener Pro 3 tools and Color Efex Pro 4 filters from the Google Nik collection.

Right ascension: 19h 43m 22s | Declination: +23° 16′ 13″ | Distance: 6,000 Light Years
Field of view: 54 x 37 arcmin

Camera: SBIG ST-10XME
Telescope: APM 152-1200ED F/6.2 with Riccardi x0.75 Reducer
Guiding: Off-axis with Lodestar guider
Filters: Astrodon Ha (3nm), OIII (3nm), SII (3nm)
Exposures: Ha 27 x 20 min, OIII 35 x 20 min, SII 33 x 20 min
Total exposure: 31.7 hours
Image composition: False Colour Hubble Palette (SII, Ha, OIII mapped to RGB)
Scale: 1.49 arcsec/pixel
Image acquired: July – September 2014

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL; Photoshop CS4; Focus Magic; Color Efex Pro 4, Sharpener Pro 3

 

North America & Pelican Nebulae – NGC7000 & IC5070

NAN&Pel-v03labThe North America and Pelican nebulae are a pair of emission nebulae in the constellation of Cygnus. Both nebulae are part of the same interstellar cloud of ionised hydrogen (H II region).  Between us and the H II region is a band of interstellar dust that is absorbing the light of the stars and nebulae behind and which gives the shape to the nebulae as we see them.  In this wide-field image it is easy to see how these nebulae got their names.  The distance of the nebulae are not precisely known nor is the star responsible for ionising the hydrogen so that it emits light.  If the star is Deneb as is often assumed then the nebula complex would be about 1,800 light years distant and 100 light years across.

This is the first light image from the QSI-583 Pentax 6×7 lens wide-field imaging rig I built over the summer.  The rig is mounted on an EQ6 mount housed in the Anser observatory – my relocated observatory situated in the Polden Hills of Somerset

Right ascension: 20h 52m 52.2s | Declination: +43° 45′ 06.8″ | Distance: 1,800 Light Years
Field of view: 373 x 281 arcmin

Camera: QSI 583
Telescope: SMC Pentax 6×7 165mm Lens F/2.8
Guiding: Off-axis with Lodestar guider
Filters: Baader Ha (7nm), OIII (8.5nm), SII (8nm)
Exposures: Ha 23 x 15 min, OIII 25 x 15 min, SII 32 x 15 min
Total exposure: 20 hours
Image composition: False Colour Hubble Palette (RGB mapped to SII, Ha, OIII)
Scale: 6.7 arcsec/pixel
Image acquired: July – September 2014

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

Crescent Nebula (NGC6888) – First Light Anser Observatory

NGC6888-bicolour-v1lceThe Crescent nebula is an emission nebula in the constellation of Cygnus about 5000 light-years away.  It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (the bright star at the centre of the nebula) colliding with and energising the slower moving wind ejected by the star when it became a red giant around 250,000 – 400,000 years ago. The shock waves from this collision can be seen in the image.  This image was created by combining emission-line images in Hydrogen-alpha and Oxygen [O III] using the Modified Bicolour Narrowband Technique developed by Steve Cannistra.

This is a double first light image.  It is the first published image from the Anser Observatory – my relocated observatory situated in the Polden Hills of Somerset.  It is also the first light image from my new APM 152-1200ED APO Refractor.

Right ascension: 20h 12m 07s | Declination: +38° 19′ 41″ | Distance: 5,000 Light Years
Field of view: 54 x 37 arcmin
Camera: SBIG ST-10XME
Telescope: APM 152-1200ED F/6.2 with Riccardi x0.75 Reducer
Guiding: Off-axis with Lodestar guider
Filters: Astrodon Ha (3nm), OIII (3nm)
Exposures: Ha 19 x 20 min, OIII 36 x 20 min
Total exposure: 18.3 hours
Image composition: Cannistra Modified Bicolour Narrowband Technique
Scale: 1.49 arcsec/pixel
Image acquired: May – July 2014

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

M17 – The Omega Nebula

M17-v2hpLocated in the rich star fields of the Sagittarius area of the Milky Way, the Omega Nebula is one of the brightest and most massive star-forming regions of our galaxy. The visible nebula is illuminated by the massive stellar cluster NGC 6618. The core of the cluster is exceedingly rich in massive young stars and may contain up to 100 “O” and “B” type stars which illuminate the nebula although the stars are heavily obscured by dense and dusty foreground clouds.

Right ascension: 18h 20m 48s | Declination: -16° 11′ 04″ | Distance: 5,500 Light Years
Field of view: 57 x 38 arcmin

Camera: SBIG STL-6303E
Telescope: PlaneWave Instruments CDK 12.5 F/7.9
Guiding: External 80mm F/4 guidescope with an Atik 314L+ for guiding
Mount: Paramount PME
Filters: Astrodon Ha (5nm), OIII (5nm), SII (5nm)
Exposures: Ha 24 x 10 min; OIII 24 x 10 min; SII 21 x 10 min
Total exposure: 9.5 hours
Image composition: Colour Mapped Narrowband SII:Ha:OIII (Hubble Palette)
Scale: 0.73 arcsec/pixel
Image acquired: 16-30 July 2013 from AstroCamp, Nerpio, S.E. Spain

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

IC1318 – Butterfly Nebula (Part C)

IC1318-v3Located in the Cygnus complex the Butterfly nebula (IC1318) is a single giant HII cloud bisected by a thick obscuring dust lane that gives the symmetry from which its 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)