Help with M27

[Roy@Aldermaston]

For some time now I've trying to get a decent image of M27, but I'm struggling with the light skies and light pollution. Through the eyepiece the nebula is barely visible and the more I increase the exposure and gain the worse the noise gets. After stacking with dark frames, the result is a very grainy image that needs a lot of processing to make the DSO stand out from the background. Anyway, I though that I would post the picture and ask for any suggestions about improving it. I used the following camera and settings:

[Philips SPC 900NC PC Camera (LX Mode)]

Resolution=640x480

Frame Rate (fps)=5.00

Colour Space / Compression=YUY2

Exposure (s)=64.2423256763574

Output Format=PNG files (*.png)

Brightness=75

Contrast=42

Saturation=27

Gamma=18

ColorEnable=255

BacklightCompensation=0

Gain=44

[shaunster]

That already looks really good to me. One of the best ive seen taken with a webcam

[ollypenrice]

Indeed.

All you ever really need for DSO imaging is ten times as much data. You could have another go and combine the stacks, several times.

Anyway, I'm impressed.

Olly

[Ags]

I had no idea a webcam could produce such a good image!

[rfdesigner]

Excellent pic..

Trying to help...

one setting says : 5fps, yet another says Exposure = 64. seconds.

Could you explain the settings with a little more detail?

Derek

[astro mick]

Hi Roy.

This is,nt a technical answer to your question,but i,m sure more qualified people than me can help.

Overall that is a very good image,and the only thing thats spoiling it is as you say,the noise,and grain.You can improve it overall by a bit more work in Photo-shop,and a great free programme called neat image.

This is a quick and dirty fix,but will help until you get your settings sorted out.

Hope you dont mind,but had a play and came up with this.

Great original image though.

Mick.

[Tom How]

IS that a single 60s exposure, or multiple exposures stacked together?

[Roy@Aldermaston]

First of all thanks for the many replies and the helpful suggestions. I took only 5 lights and darks for stacking, and all were 60s exposures. I realise five subs is too few, but it was about 2 am and it took so long to get the extremely faint image on the laptop screen that I was getting quite frustrated.

The long exposure modded webcams seem quite capable of producing images approaching the quality of those produced by DSLRs, but in general they do seem underrated for DSO work. I've been really impressed by some of the images taken with these cameras and posted on the Astronomyshed forum.

I'm using SharpCap, which even in long exposure mode offers a choice of frames per second setting independently of the exposure, but I'm not quite sure how the two settings relate to the output. Whatever fps setting is used, the output still consists of single png frames at the selected exposure.

Mick, no objection whatsoever, I much prefer your version. Could you do me a favour and post the details of the processing that you used?

Roy

[Cloudwatcher]

How about a sharpened saturated version?

Incidentally,is this a crop of a larger image?

[Tom How]

the fps relates to using the webcam for video. For astro work, ALWAYS set it to 5fps to get the least compression artifacts.

NB I know how hard it is to get something on a tiny webcam sensor, but try and avoid the edges/corners for your target otherwise the dreaded amp-glow effects things.

[Tom How]

NB I always used to use RAW mode on my webcams when I did DSO work with them

Astronomy modified webcam RAW mode... what's it all about?

[Roy@Aldermaston]

Positioning the image in the corner was a mistake, but by that stage I was desperate to get anything on the screen. Thanks for the info on webcam RAW image format, that's something that I will have to look into.

Roy

[astro mick]

Roy.

I will PM you to-morrow.

Regards.

Mick.

[Roy@Aldermaston]

Mick,

PM sent. I'll have a go at reworking the image as soon as I have some free time.

Thanks,

Roy

[ollypenrice]

Neat Image wasn't free when I bought it!!

Olly

[astro mick]

Hi Olly.

Its the Demo version only,it allows basic use of its facilities,but its enough to play around with,especially at my level of processing.

Dont feel too bad.

Mick.

[Roy@Aldermaston]

I've followed much of the advice for processing and this is result. It doesn't overcome the basic problems with exposure, gain and too few frames for stacking, but I think that its a definite improvement.

Roy

[astro mick]

Nice one Roy.Big improvement,i,m sure your very pleased with it.

Well done.

Mick.

[Coco]

Very well done Roy, there no mistaking the target, I think you've done an excellent job.

[Roy@Aldermaston]

Thanks Mick and Guy,

All we need now are clear skies and less wind - if you have any influence it would be greatly appreciated!

Roy

[fatwoul]

The original result, with just 5 minutes of data on a webcam, is remarkable. I think you owe that little camera a hug.

[Roy@Aldermaston]

They are very good. It's early days yet, but I'm sure that with more practice the results will improve. I bought my first telescope in November 2010 (Nexstar 4SE) so I'm still very much a novice, but thoroughly enjoying the steep learning curve.

Roy

[Tim]

That already looks really good to me. One of the best ive seen taken with a webcam

Me too, webcams arent ideal for this type of DSO, I am amazed at what you have!

[Tim]

The long exposure modded webcams seem quite capable of producing images approaching the quality of those produced by DSLRs, but in general they do seem underrated for DSO work.

One limiting factor is that the webcam is 8 bit depth, but on bright targets like planets they are ideal.

DSLRs are generally 12-14 bits, and CCD cameras tend to be 16bit. When capturing faint stuff, the extra dynamic range really becomes evident.

[Roy@Aldermaston]

Are you sure about that? The Phillips SP900NC uses a Sony CCD chip and its my understanding that it can capture 24 bit colour.

Roy