Tarantula (NGC2070) – Data from March 2013

[IanP]

Originally Posted by tilbrook@rbe.ne

That's a nice Tarantula Ian!
Lovely blend of colours, so hard to get right but you nailed it!
Cheers,
Justin.

Thanks Justin for your comments.

Colour is always a struggle ..

[Jon (Jonathan)]

Nice image, and very interesting conversation.

I too have a 60Da and after six months of fumbling I settled on iSO800. Once I realised that the higher ISO didn't result in any capture of actual fainter detail - same detail (and noise) captured, just at half the scale - it all fell into place. I had to get good enough at post-processing - stretching the faint detail away from the background - before I came to that understanding.

I've also started using a Astronomik CLS LP filter with good results. Sure, the subs have to be longer. But I can go to 8-10 minutes from the suburbs with no problem using the LP filter.

I don't quite understand the comment about losing faint detail with the LP filter. Sure, for visual, any filter reduces the limiting magnitude some. But imaging doesn't work in the same way. Faint detail isn't about the absolute strength of the photons reaching the sensor (as it is for your eye); it's about the difference between the level of the detail and that of the background noise. An LP filter cuts out (especially) the orange sodium background, allowing the fainter details at other wavelengths to come through.

I've got two images of the Helix Nebula, both 2 hrs data, neither processed for noise reduction. The first is from May, with no LP filter, ISO 1600, 30 x 240s subs. ....

[Jon (Jonathan)]

... The second is ISO 800, Astronomik CLS Filter, 16 x 8 min subs. Both with EOS 60 Da through a 10" Meade LX200 with f/6.3 reducer.

Chalk and cheese, IMHO. Much more detail with the lower ISO and the filter.

[Apologies for splitting the post; my iPad can't attach more than one file to a single post. When I get home I'll try to edit them together]