Monthly Archives: March 2016

Melotte 15 at the heart of the Heart Nebula (IC1805)

Heart-IC1805-BiColour v3.1a

The open star cluster at the centre of this image is known as Melotte 15 and is embedded within a central portion of the much larger glowing nebula known as the Heart Nebula. The gnarled structure is a massive area of glowing ionised hydrogen where dust and gas clouds are sculpted by the intense pressure of the solar wind and ultraviolet radiation from the massive hot stars making up the Melotte 15 cluster.

Poor weather across Britain during autumn and winter 2015 meant there were few clear nights and it has taken over 6 months to acquire 23 hours of Ha and OIII data.  Note that I am now taking 30 minute exposures with the 10Micron GM1000 HPS in combination with active optics guiding consistently delivering perfectly round stars.

Right ascension: 02h 33m 41s | Declination: +61° 23′ 31″ | Distance: 7,500 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
Mount: 10Micron GM1000 HPS
Filters: Astrodon Ha (3nm), OIII (3nm)
Exposures: Ha 24 x 30 min, OIII 22 x 30 min
Total exposure: 23 hours
Image composition: Cannistra Modified Bicolour Narrowband Technique
Scale: 1.15 arcsec/pixel
Image acquired: Over 7 nights between 25th September 2015 and 13th March 2016

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL; PixInsight Deconvolution, Photoshop CC 2014, Color Efex Pro

New 10Micron GM1000 HPS equatorial mounting

GM-1000-10Micron_v1I have been operating the 10Micron GM1000 HPS mount with my APM 6 inch refractor since beginning of November 2015. It is a superbly well engineered and extremely accurate mount. Building a sky model and polar aligning the mount are straightforward tasks and I achieved very accurate results with minimal effort on first attempt. I am very pleased to have retired the AZ-EQ6 GT which was driving me mad with mediocre tracking and undiagnosed driver/USB connection issues causing occasional loss of synchronisation with the ACP pointing model. The GM1000 is in a different class with a price tag to match but I am now able to just concentrate on imaging and the only limiting factor is sky quality.

Many users of this mount take advantage of its extreme accuracy to abandon guiding however I am currently using active optics guiding with a Starlight Xpress SXV-AO-LF unit. As tracking error will be minimal the premise is that it may be possible to correct for residual fluctuations due to atmospheric turbulence (seeing). I will be conducting experiments with and without AO guiding to see if I can gather any evidence to support this proposition.

NGC 7635 The Bubble Nebula

Bubble-Bicolour-v2The Bubble Nebula is a shell of gas surrounding a massive O star (BD+602522) which can be seen in the upper right quadrant of the bubble. The star is several hundred thousand times more luminous and around 45 times more massive than our Sun. A fierce stellar wind and intense radiation from the star ionizes the shell causing it to glow. About six light-years in diameter, the Bubble Nebula is located in the direction of the constellation Cassiopeia. The expansion of the bubble is contained by the surrounding giant molecular cloud.

As there was barely sufficient OIII data to produce a colour image, a false colour RGB image was created using the bicolour processing technique and then the Ha image was recombined as the luminance channel. This allows colour noise reduction, elimination of star halos and Gaussian smoothing prior to adding the Ha luminance layer. The final image was selectively smoothed, sharpened and colour enhanced using Photoshop and Color Efex Pro.

Right ascension: 23h 20m 45s | Declination: +61° 10′ 31″ | Distance: 11,000 Light Years
Field of view: 42 x 28 arcmin
Camera: SBIG ST-10XME
Telescope: APM 152-1200ED F/7.9
Guiding: Off-axis with Lodestar guider
Filters: Astrodon Ha (3nm), OIII (3nm)
Exposures: Ha 15 x 20 min, OIII 16 x 20 min
Total exposure: 10.3 hours
Image composition: Cannistra Modified Bicolour Narrowband Technique
Scale: 1.15 arcsec/pixel
Image acquired: Over 4 nights between 27th August – 18th September 2015

Image capture with MaxIm DL, FocusMax, ACP; Image processed with MaxIm DL; Photoshop CC 2014, Color Efex Pro.