Steven Mohr
NGC3532 | Wishing Well Cluster | LHaRGB
From the Wiki…
NGC 3532 (classified by Sir Patrick Moore as Caldwell 91), also commonly known as the Pincushion Cluster, the Football Cluster, the Black Arrow Cluster and the Wishing Well Cluster, is an open cluster some 405 parsecs from Earth in the constellation Carina. Its population of approximately 150 stars of 7th magnitude or fainter includes seven red giants and seven white dwarfs.On 20 May 1990 it became the first target ever observed by the Hubble Space Telescope. A line from Beta Crucis through Delta Crucis passes somewhat to the north of NGC 3532. The cluster lies between the constellation Crux and the larger but fainter "False Cross" asterism. The 4th-magnitude Cepheid variable star x Carinae (V382 Car) appears near the southeast fringes, but it lies between the Sun and the cluster and is not a member of the cluster.
The cluster was first catalogued by Nicolas Louis de Lacaille in 1751. It was admired by John Herschel, who thought it one of the finest star clusters in the sky, with many double stars (binary stars).
About processing this image…
Anyone trying to process this object will quickly realise the field is overwhelmed by the brightness of the main star cluster, with the faint background nebulosity being a trick to bring out without destroying the stars. In the end, I have actually used the Ha stars for the main cluster [so I lost some of the very faintest stars], and created an artificial flat in the base colour of the star glow, selectively applied to where it was needed, and subtracted that out to remove the strong and massive halo from all the stars. I did apply a star mask to this artificial flat so not to change the colour of the stars whilst subtracting the selective flat. That seemed to work.
Hi res link:
live.staticflickr.com/65535/50939560953_722bc98976_o.jpg
Information about the image:
Instrument: Planewave CDK 12.5 | Focal Ratio: F8
Camera: STXL-11000 + AOX | Mount: AP900GTO
Camera Sensitivity: Lum + Ha: Bin 1x1, RGB: Bin 2x2
Exposure Details: Total: 22.6 hours | Lum: 15 x 900 sec [3.75hr], Lum: 80 x 60 sec [1.33hr], Ha: 30 x 1200 sec [10.0hr],RGB 20 x 450sec each [7.5hrs]
Viewing Location: Central Victoria, Australia.
Observatory: ScopeDome 3m
Date: January 2021
Software Enhancements: CCDStack2, CCDBand-Aid, PS, Pixinsight
Author: Steven Mohr
NGC3532 | Wishing Well Cluster | LHaRGB
From the Wiki…
NGC 3532 (classified by Sir Patrick Moore as Caldwell 91), also commonly known as the Pincushion Cluster, the Football Cluster, the Black Arrow Cluster and the Wishing Well Cluster, is an open cluster some 405 parsecs from Earth in the constellation Carina. Its population of approximately 150 stars of 7th magnitude or fainter includes seven red giants and seven white dwarfs.On 20 May 1990 it became the first target ever observed by the Hubble Space Telescope. A line from Beta Crucis through Delta Crucis passes somewhat to the north of NGC 3532. The cluster lies between the constellation Crux and the larger but fainter "False Cross" asterism. The 4th-magnitude Cepheid variable star x Carinae (V382 Car) appears near the southeast fringes, but it lies between the Sun and the cluster and is not a member of the cluster.
The cluster was first catalogued by Nicolas Louis de Lacaille in 1751. It was admired by John Herschel, who thought it one of the finest star clusters in the sky, with many double stars (binary stars).
About processing this image…
Anyone trying to process this object will quickly realise the field is overwhelmed by the brightness of the main star cluster, with the faint background nebulosity being a trick to bring out without destroying the stars. In the end, I have actually used the Ha stars for the main cluster [so I lost some of the very faintest stars], and created an artificial flat in the base colour of the star glow, selectively applied to where it was needed, and subtracted that out to remove the strong and massive halo from all the stars. I did apply a star mask to this artificial flat so not to change the colour of the stars whilst subtracting the selective flat. That seemed to work.
Hi res link:
live.staticflickr.com/65535/50939560953_722bc98976_o.jpg
Information about the image:
Instrument: Planewave CDK 12.5 | Focal Ratio: F8
Camera: STXL-11000 + AOX | Mount: AP900GTO
Camera Sensitivity: Lum + Ha: Bin 1x1, RGB: Bin 2x2
Exposure Details: Total: 22.6 hours | Lum: 15 x 900 sec [3.75hr], Lum: 80 x 60 sec [1.33hr], Ha: 30 x 1200 sec [10.0hr],RGB 20 x 450sec each [7.5hrs]
Viewing Location: Central Victoria, Australia.
Observatory: ScopeDome 3m
Date: January 2021
Software Enhancements: CCDStack2, CCDBand-Aid, PS, Pixinsight
Author: Steven Mohr