In order for these images to be displayed properly, adjust your monitor so that all of the gradations of black to white in the following chart are distinguishable, especially the two darkest shades. Generally monitor contrast should be set as high as is consistent with comfortable viewing, and then the brightness adjusted. The darkest shade should appear black.
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Supernova Search ProgramIn February 2007 I started a supernova search program using my C9.25 telescope, Vixen GPD mount, ART 285 CCD camera and several pieces of software which I wrote. These consist of; 1. GalaxyGen - a script to generate a list of galaxy targets suitable for a night's observing run. This also generates a list that can be used to download reference DSS images (see below). The main issue the search algorithm has to account for is that my polar alignment (non permanent mount) is not perfect, so that a large excursion away from the initial alignment point in terms of azimuth and altitude will lead to inaccurate pointing and failure to acquire the target. This is overcome by picking targets within a narrow band of declination, but with increasing RA through the observing run, such that the telescope always points to approximately the same alt-az point. 2. TargetPoint - a script that controls the mount and camera and successively points the telescope to each galaxy on the list, acquiring a set number of images of each target. 3. Examiner - a script that enable quick comparison of these images to reference images downloaded from the Digitized Sky Survey (DSS). Typically between 150 to 200 galaxies can be observed in an automated overnight run. Using individual 20s exposures, supernovae down to mag 17 should be detectable. Proof of concept was achieved when a supernovae was detected in PGC51820 (ESO385-32) on 14th March 2007. Subsequent checking revealed that this SN had been discovered about a month previously and is designated SN2007X. Below is a image of this supernova;
NEW My second supernova discovery! SN2008ff was discovered on 29th Aug 2008 in ESO284-32 (PGC 64319). Location: RA: 20h 13m 59.96s DEC: -44d 21' 7.8", 39" east and 1" south of host galaxy nucleus mV = 15.5 on 2008/09/1.52 UT
My first, SN2007rv was discovered on 7th Nov 2007 in NGC 689. Location: RA: 01h 49m 52.86s DEC: -27d 28' 4.1", 14" east and 4" south of host galaxy nucleus mV = 15.9 on 2007/11/11.51 UT
New imagesThe most recent images now include some taken with a home-assembled CCD camera, the Artemis 285. This is a cooled 16-bit camera based on the 1.4 Megapixel Sony ICX285AL chip. Other images were taken with a Digital SLR (Canon EOS300D) modified using a procedure described by Terry Lovejoy and Gary Honis. The modification involves removing the internal IR-cut filter which severely reduces the camera's sensitivity to the important hydrogen-alpha wavelength. Some words of warning - making this modification obviously invalidates your camera warranty. There is also a fair bit of fine work involved and you run a real risk of ruining your camera! I had to open up the camera and readjust some connections 3 times, before the camera would work properly again. I did not replace the original filter with a less aggressive IR cut filter, nor another piece of glass, so the camera now does not auto-focus properly and, because of it's response to IR, its colour rendition is severely compromised for normal photographs. You have been warned... A more complete set of images from the DSLR is at the DSLR Gallery. A summary of my equipment. I use an Orion 80ED refractor, a Celestron C9.25 Schmidt-Cassegrain, usually used with a x0.63 focal reducer, and a Vixen GPD mount with SkySensor 2000 PC. The Go To facility makes for very easy target location.
All DSLR images were acquired with the help of DSLR Focus software, to help with equatorial alignment, focusing, and automating the multiple exposures. Shutter control was using a serial cable I made up following instructions here. Image processing was in Iris, which has marvellous tools for handling DSLR RAW files, and finished in Photoshop CS.
A selection of SAC7B imagesThis is a selection of older images made with a commercially converted webcam - the SAC7B.
Other SAC7 images can be viewed in the Webcam Gallery.
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This page is maintained by TG Tan and was last updated on 20 September 2008 |
