M57 Ring Nebula 21st and 22nd May 2011

Carole · May 23, 2011, 17:35:10

My 3rd image from last night. Due to cloud taken over 2 nights.

Total of 15 x 5min subs 800 ISO + darks flats and bias
Skywatcher ED120 Pro, guided with PHD and QHY5
Modified Canon DSLR EOS 450D + CLs Clip filter
NEQ6, and processed with DSS and PS CS3

Carole

MarkS · May 23, 2011, 22:00:17

Is this a crop of the full-scale image? Or have you re-sampled it to make it bigger? It just seems a bit blurry. The colour balance is good though.

Mark

Carole · May 24, 2011, 08:50:00

It's a gigantic crop Mark, so much so I had to increase the resolution as you could see the pixels so on a DSLR that is a huge zoom.

This is the full frame. I guess at that level, any slight discrepancy in focus is going to be increased.

mickw · May 24, 2011, 09:46:50

Wouldn't your ETX do a better job with that ?
You could crop out any vignetting

Carole · May 24, 2011, 11:03:28

QuoteInsert Quote
Wouldn't your ETX do a better job with that ?

You know I was just thinking the same thing myself Mick. Means I'll have to do loads of subs to make up for the increased Focal ratio. I'll have a go at that next time.

Guys, it is more subs or longer subs I need to do at F15?

Carole

Mac · May 24, 2011, 11:21:42

Both.

Mac.

Carole · May 24, 2011, 11:46:18

Thanks Mac, will give it a go and see how it works out.

Carole

MarkS · May 25, 2011, 10:15:11

Quote from: Carole
It's a gigantic crop Mark, so much so I had to increase the resolution as you could see the pixels so on a DSLR that is a huge zoom.

Carole,

If you've resampled the data to make your cropped image larger then that explains it. There's nothing at all wrong with resampling an image but it does give it a more "blurry" appearance. It doesn't mean your acquired data is out of focus.

Mark

Carole · May 25, 2011, 11:18:02

Thanks Mark.
Is this better, I've done a larger crop and not increased the resolution this time.

Carole · May 29, 2011, 18:34:21

Been introduced to Smart sharpen, to sharpen up images slightly out of focus.

mickw · May 29, 2011, 20:36:26

It's put haloes round the bright bits and stars

Carole · May 29, 2011, 22:01:52

QuoteIt's put haloes round the bright bits and stars

So it has. Didn't notice that until you pointed it out, and even then had to look at the monitor from a different angle.

Oh well, back to the drawing board.

Carole

Carole · May 30, 2011, 08:22:57

OK, one last attempt

Fay · May 30, 2011, 16:54:39

Light bit looks too light, now

Carole · May 30, 2011, 20:22:39

I think I did the adjustments to the Jpeg in error, will have one last try as soon as I get a chance.

Carole

Orpington Astronomical Society

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