NGC6888 from Rother Valley

[MarkS]

Here's my version of NGC6888 taken Friday 9th July at Rother Valley DSC.  Transparency was very good but guiding was not so good - I think everyone suffered bad guiding that evening.

Modified Canon 350D on Tak Epsilon 180ED ( F2.8 at 500mm) with Astronomik CLS filter.
26 x 5min at ISO 800
6 x 5min at ISO 100
Both sets of images stacked separately then combined into a single HDR image and asinh scaling applied.  This is a quick proof of concept of the acquisition and processing methods I intend to use from now on.
A few hot pixels, satellite trails and black speckles still need to be addressed.

Crop of the full image:


It certainly needs more data to enhance the Ha but I'm pleasantly surprised to see just a hint of the OIII envelope around the Crescent Neb.

Full image is here (3Mbyte):
http://www.markshelley.co.uk/Astronomy/2010/ngc6888_09072010.jpg

Mark

[Carole]

Lovely colours Mark, guiding looks fine to me.

Carole

[The Thing]

HDR processing - interesting. I was just reading about the relationship between CCD dynamic range and ISO and the trade offs to preserve star colour or make it recoverable in a piece by Jerry Lodigruss. He has a description of HDR image processing as well, useful site http://www.astropix.com/HTML/J_DIGIT/PS_HDR.HTM.

[Rocket Pooch]

Hi Mark,

The guiding looks ok to me?  Its a nice image as well.

Chris

[MarkS]

The standard deviation of the guiding errors was approximately double what it usually is.  This hasn't caused distortions in the star shapes but it has made the stars larger than they would otherwise be.

I'm actually not very happy with the image - overall it just doesn't "look right" to me - but I can't quite put my finger on what I don't like about it.   When I get some more time I'll have another play with it.

It definitely needs more data, though - there's not quite enough Ha.

Mark

[Fay]

Yes the guiding was difficult for some reason, those nights, Mark. Still a nice image though, great colours

[Rocket Pooch]

If it was the friday mine was also a little high as well, there is a tip here, if you slighly increase the guide image the mount and software does not overcorrect.  I put my guide image from .6 to 1 second on friday, I then got nearly the same as earlier in the week.

Chris

[Mac]

Fantastic detail in the large image.

Mac.

[The Thing]

Yes, fantastic detail in the large image. There is another big nebulous patch everywhere - but I guess that's an interstellar vacuum for you...