Southern Cross Region

This is a wide field view of the Southern Cross area. On the left is the two pointers (Rigel Kentaurus and Hadar) , the Southern Cross (Crux) & the Coal Sack in the centre and Carina on the right. The pink nebula on the right is the Eta Carina Nebula. It is 9000 light years away and is a likely candidate for an outburst any time soon. It’s last large outburst was in 1841. In 1999 it doubled in brightness and in 2007 it was a naked eye star.   It’s current magnitude is about 4.6. Watch this space….

The fuzzy ball on the top left is the Omega Centauri globular cluster, very likely the home of a black hole in it’s centre. This cluster contains millions of stars and is 15,800 light years from earth and is the apparent diameter of the full moon. It is easily visible in binoculars (10×50). Look at the Astronomy Picture of the Day for a great photo of Omega Centauri.

Southern Cross Region 1s

Photo taken last night with Canon 600D, Tokina 11-16mm at 14mm, f/2.8, ISO1600. Nine light frames of 20 seconds each stacked with Deep Sky Stacker and a little processing with IRIS and PS CS2. I cropped the image quite a bit.

Next time I will make the exposures shorter (~ 8 seconds) and take many more (~50). The camera is static on a tripod and 20 seconds are just starting to show oval stars. The final image will probably be much sharper with shorter exposures. It should also get rid of the overexposed bright stars.

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6 thoughts on “Southern Cross Region

  1. Rudi Venter

    Great photo Theo! Looks like the Tokina is producing the goods!
    I have used a Sigma 12-24 for similar images but it is only a f/3.5. I do use ISO up to 6400 so that helps a bit (Canon 5D3) I normally try to take 20+ frames also using Deep Sky stacker.

    Thanks for sharing your photos, I am enjoying them!

    Regards,
    Rudi

    Reply
    1. Theo Post author

      Hi Rudi,
      Thanks. It will be a while before I can compete with you. Your photos are fantastic!
      I am a bit careful with using high ISO as the noise picks up very quickly. The higher number of frames will get of some of the noise but if I dont need the high ISO I stay with 800 or 1600. Its the great trade off between light, star trials and noise. We want short exposures where the starts are nice and round while having low noise and enough light. I guess its this challenge that makes one come back to do it all over again the next night. If it was too easy, I would become bored quicky.
      Cheers,
      Theo

  2. Rudi Venter

    Hi Theo,

    Thanks for the compliment!

    I agree, if you can stay away from high ISO it is better, as a matter of interest, are you also using dark frames? I found that helped a lot as well, even when done “in camera” but best when used along with the stacking software. I wish I was in a place with less light pollution, most of the astro photos I have taken were taken in Namibia while on safari. It is true, if it is too easy it soon becomes boring!
    Keep well,
    Cheers,
    Rudi

    Reply
    1. Theo Post author

      Rudi,

      I usually take at least 3 dark frames and a few bias frames as well when its an astronomy image. I dont bother for sunset and daytime landscapes. I still have to try out flats.

      I have heard someone say that you should use the light pollution rather than try and avoid it. It is good to use light pollution to light up a tree or something else in the foreground of a long exposure.

      Cheers,
      Theo

  3. Rudi Venter

    Theo,

    Thanks for the reply, yes, dark frames help a lot with astronomy images. I used to take 3 or more images for landscapes if the contrast was high and combine them into a “almost hdr” but these days I find a single RAW image and LR4 works just as well if not better. We have come a long way with our DSLRs!

    Interesting idea to use the light pollution, I can see that it can help to create some interesting images, must give it a try!

    Cheers,
    Rudi

    Reply
  4. Pingback: The Brightest Star In The Southern Cross | David Reneke | Space and Astronomy News

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