Star trails - single exposure blunder

[alexch (Alex)]

Hi All,

This is the last image from my recent trip to Phillip Island.

I recently started using the fancy interval timer that allows me to go beyond 30 seconds and thought I'd do the single 64 minute exposure at ISO 200 to save time in post-processing avoid stacking. Oh dear, was I wrong!

The noise in the image was so horrendous that I decided to give up on it and re-take it some other time as a stack of 4-minute exposures. But yesterday I downloaded Photoshop CS5 trial and gave it a go on this image. It took a few hours to learn the new tricks in CS5 (been using CS2) and clean it up. The result is not great, but good enough for web presentation and up to A3 sized print.

I used "Select-Colour range" then the very cool content-aware healing brush and finally colour noise reduction. I must admit I am impressed with CS5 speed and new features.

Below are 100% crops of before and after processing in CS5 as well as the final image resized for web.

Cheers,
Alex

[Jaybee (John)]

Wow, I'd be more than happy with that, Nice pic Alex

[mswhin63 (Malcolm)]

Nice job, probably darks would have fixed a lot of the colour blotching. If using a Canon DSLR they have a similar cleanup in DPP.

[alexch (Alex)]

Originally Posted by mswhin63

Nice job, probably darks would have fixed a lot of the colour blotching. If using a Canon DSLR they have a similar cleanup in DPP.

I had no juice in the batteries left to take a 64-minute dark frame. I reckon it is easier to just stack shorter exposures and let the noise cancel itself out.
It was just an exercise to learn Photoshop CS5.

[mswhin63 (Malcolm)]

Try Startrails program and much shorter exosures works really well for me

[Liz]

Wow, number 1 is beautiful Alex!!!!! Love a lot of star trails, and over the sea and rock. Poster stuff.

[David Fitz-Henr]

I agree with Liz - that's a brilliant image that would look good gracing the cover of any astronomy magazine!

[Bassnut (Fred)]

wow, the 1st pic is surreal, brilliant.

Thats interesting about CS5, do you think it has features that make it worth upgrading from CS2 for Astro?.

[alexch (Alex)]

Thanks!

Originally Posted by Bassnut

wow, the 1st pic is surreal, brilliant.

Thats interesting about CS5, do you think it has features that make it worth upgrading from CS2 for Astro?.

I am not sure about astro-photography because my experience is limited to ultra-wide night shots on a fixed tripod. However for normal photography post-processing - the answer is definitely yes. Content-aware fill and healing brush are simply amazing. Panorama blending is very good too and so is HDR mapping. I did not feel compelled to upgrade until now, but I think I will. Try it - fully functional 30 day trial is avaialble for download (800MB).

[alexch (Alex)]

Originally Posted by Liz

Wow, number 1 is beautiful Alex!!!!! Love a lot of star trails, and over the sea and rock. Poster stuff.

Thanks!

[Bassnut (Fred)]

Thanks Alex, the healing tool alone sounds interesting, my friend. Ill give the trial a go.

[leon]

Nothing wrong with that Alex, love the first one. well done indeed.
Leon