Sky at a Glance

FITS images of a range of astronomical objects are available   to members on a CD.  These have been taken by members using some of the largest telescopes, available for amateur use, around the world.  Below is a list of images available and each dataset is about 25 MB.

Processing FITS files

FITS files are 16 bit wide data giving 65,336 levels e.g. there will be 65,334 tones of grey between black and white.  A normal computer screen uses 8 bit data giving 256 levels.  256 levels is about the maximum that the eye can distinguish on a computer screen.  Why use 16 bit.  In an astro image there is an enormous amount of information compressed at either end of the range and by using specialist software you can expand the regions that contain a lot of data and compress regions where there is little data.  This allows you to bring out detail that otherwise would not be visible on the screen.  Much of the software that is available to handle FITS astro images comes at a price but ESA/NASA have produced a good piece of software called FITS Liberator that is free to download from their Hubble site.  There is also a comprehensive user manual on the same site.


maryspicerFor those wanting to try some nightsky photography themselves, we have the notes from Mary McIntyres February 2017 meeting presentation available here (for logged in members).


Having manipulated the images with your free software (three images if it is a colour photo) you can save and convert to a conventional format such as TIFF.  The images can then be opened in convention artwork packages such as Photoshop, Paintshop Pro etc or a free artwork package from the Internet.  If you are making a colour image there will be three converted FITS files, R, V and B which are all black and white.  In your artwork package each image has to be colourised (R ~ red; V ~ green, B ~ blue) and then stacked to form the final image.  The Hubble site gives an indication how this can be done manually.

Available images...


IC 4725 ~ Open Cluster (M25)

NGC 1952 ~ Crab Nebula (M1)

NGC 3242 ~ Ghost of Jupiter (C59)

NGC 5128 ~ Centuraus A galaxy

NGC 5139 ~ Omega Centauri Globular Cluster

NGC 5189 ~ Spiral Planetary Nebula (IC 4274)

NGC 6523 ~ Lagoon Nebula (M8)

NGC 6720 ~ Ring Nebula (M57)

NGC 6744 ~ Spiral Galaxy (C101)

NGC 6853 ~ Dumbbell Nebula (M27)

NGC 6946 ~ Fireworks Galaxy (C12)

NGC 7009 ~ Saturn Nebula (C55)

NGC 7078 ~ Globular Cluster (M15)

NGC 7320 ~ Stephen's Quintent (four galaxies) 

NGC 7331 ~ Spiral Galaxy (C30)

Comet C-2009 P1 ~ Comet Garradd



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