The Window Sill Observatory

September 3, 2011

Moving Comet or Moving Stars?

Filed under: Animations, Software — Dave @ 11:46 am

WSO hotshot Mike has reworked some old images of Comet Harley with DVS to produce two time-lapse animations.

In the first, he used a star as the alignment anchor in DVS. This locks the starfield in place and the comet appears to move. (Right-click on these videos if you want to turn on looping).

He then used the comet as the alignment anchor and this time the stars appear to move while the comet stays still.

The second method will be good for watching the comet evolve over time. We are currently testing DSSR’s comet tracking module.

ps – Check out Mike’s first solar prominence animation as well – a DSSR/DVS collaboration.

All of these animations were produced before DVS’s sub-pixel alignment was finalised.

Nice videos Mike.



  1. The comet Harley videos were created from a sequence of about 114 still images taken at one minute intervals with a Canon 40D DSLR through a Celestron CPC800 telescope from a very light polluted site on the evening of 10th October 2010.

    The images were originally stacked in Deep Sky Stacker to produce a single ‘composite’ image with the comet stationary against the star backround. This can be seen here:

    Recently, during a sunless day when I was testing the DSSR and DVS programmes, I decided to explore the viability of using DVS to produce a time-lapse video showig the quite significant movement of the comet against the star background over the two hour period. I batch processed the images in Photoshop to increase brightness and contrast and used a distinctive group of stars as the ‘anchor’ in DVS. This worked quite well and the result can be seen in the first video above.
    After some discussion with Dave, I decided to try to anchor on the comet and allow the stars to drift. If this worked, it would suggest that DSSR could be used to guide on and image bright comets and planets as well as working on the sun. As the comet moves quite a long way during the 2 hours, I only used about 50 frames and I had to increase the value of the ‘drift’ setting to about 250 to prevent the comet as the ‘anchor’ from being lost. Once again, the process worked pretty well as can be seen in the second video shown here.

    The results suggest that DSSR should work well to track and image planets and bright comets and I will explore this further once the clouds go away!

    Mike Garbett

    Comment by dnaboy — September 4, 2011 @ 1:09 pm

    • Good notes Mike – very useful with comet Garradd coming up.

      For the record, DSSR can guide on planets and stars as well. I have even guided on one of Jupiter’s moons. A full list of features is in the DSSR page at top right.


      Comment by Dave — September 5, 2011 @ 7:55 am

  2. I like the idea of aligning on the comet with the star field moving it gives a great impression of movement.

    Comment by photosbykevPhotosbykev — September 4, 2011 @ 3:14 pm

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