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Kemble's Cascade


Shibby
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Wow, it was windy out there tonight. But my first opportunity to get the scope out in the last 5 weeks, so couldn't refuse! I thought with the wind it would make sense to stick to a wide field, so this is my first mosaic.

Covering some 3 degrees, Kembe's Cascade is a lovely asterism of colourful stars; a chance alignment, seen here in a line from bottom left to top right. On the end of the chain hangs open cluster NGC1502.

I was just observing at first, and I can highly recommend this great view in a wide angle eyepiece.

2 x 10 x 60s, ISO-800 unguided

shibby-albums-latest-images-picture13248-kembles-cascade.jpg

I think longer subs would have helped bloat the bright stars in the asterism a bit better, perhaps making it a bit more obvious.

Edited by Shibby
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I think longer subs would have helped bloat the bright stars in the asterism a bit better, perhaps making it a bit more obvious.

That is a lovely image. You can make the asterism more obvious by using StarSpikesPro2 - which gives the facility to boost the colour on particular stars and have spike or not with infinite variation. Many people don't like spikes but I quite like them on a purely stellar image. I hope you don't mind me playing with your image.

Dave

post-14654-133877658265_thumb.jpg

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Thanks guys, I would like to revisit some time with longer subs. I feel with 2 min exposures the natural spikes would show well on the cascade's stars, highlighting them over the others.

Dave, not at all! That looks really good - are the colours taken from the actual star colours in the image?? I think releasing 2 versions could be a good idea.

John, yeah 2 panes. I rotated the camera so I could fit it in to 2 panels horizontally. I then manually combined them.

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Dave, not at all! That looks really good - are the colours taken from the actual star colours in the image?? I think releasing 2 versions could be a good idea.

If you follow this link you will see what I do on my website so that if you mouse over you get the spikes otherwise not. Should keep every one happy. The StarSpikes app uses the actual star colours.

ngc457 ET/Owl Nebula

I have done Kemble's Cascade but it is not as pretty as yours :).

Dave

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Yes, that's a lovely image with very impressive star colours, well done and excellent presentation! To me, the 'cascade' shows up perfectly well in the original, without any enhancement.

If you haven't already done so, try the coathanger (Brocchi's cluster) by way of comparison - rather similar.

Edited by 661-pete
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That really is a beauty. And the star colour is splendid! Now why are you getting lovely star colour when most DSLR users just get white? is it the short subs? In which case all DSLR imagers need to think of taking a run of shorts just for key star colour.

When I want to emphasize an asterism I process the key stars a little differently. You could write an action; select with magic wand and then record: select-modify-expand. Feather. Saturation up. Maybe slight lift in curves having pinned the background level. Deselect. (Don't forget that one!)

The mosaic is spot on, too. I'd heard of the object but never seen it before. And unguided, so more applause!

Olly

Edited by ollypenrice
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Thank you all for the nice comments! It really is a lovely subject.

Olly, I think the star colours are, as you say, due to the short sub length. I also wonder if the wind played a part... I can conceive this giving each star a slight "haze".

Here's a new version. I tried out my own method of exaggerating the brighter stars:

  • Duplicate layer
  • Apply a median filter (this "eats" the smaller stars)
  • Apply a gaussian blur, then lift saturation
  • Blend the layer back in Linear Add mode.

This seems to have worked quite nicely, and helped bring out the natural diffraction spikes.

shibby-albums-latest-images-picture13281-kembles-cascade-version-2-tweak.jpg

Edited by Shibby
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  • 1 year later...

Sorry for the bump! Last week I received a message on Flickr from the producer of BBC's Sky at Night about this image; it will be used on Monday's programme (8th Oct)! :biggrin:

It's also been used on the homepage of the show's website: http://www.bbc.co.uk/programmes/b006mk7h (scroll down to bottom).

Here's the image again since all the previous ones are broken:

gallery_5051_1080_325400.jpg

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Caught it last night, half asleep having set an alarm! Dear Points of View: Why is Sky at Night on soooo late?

This image was actually shown twice because Pete Lawrence chose it as his favourite object :)

I must get out there tonight and tick off some of the binocular objects, they've picked some really interesting ones.

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