Crab Nebula (Messier 1) first attempt

[SlimPaling]

A few nights ago I managed to squeeze in a short imaging session of M1 .... 3 x 200 sec LRGB subs.

I have since spent a bit of time processing and I am amazed at just how much detail I have managed to get on so few subs !!!

If I go back and add more subs will I get an even better image?

[cfpendock]

Very, very nice indeed.  The framing is superb.  Maybe the stars are just a tad oversaturated?

But my kind of image...

Chris

[DaveS]

Very good that Mike, lots of fine detail.

Had a go at this last year but I was using NB and the result was unconvincing. I'm coming round to the idea that LRGB might be the way to go, perhaps augmented with HII and [OIII].

[Filroden]

More subs will definitely help to reduce noise in the darker areas and to support greater sharpening. Some of the fainter detail will also start to lift so you can push the stretching a little more. Though I wouldn't have believed you could get that much out of so few subs! Nice image.

[coatesg]

That is a great result for such a short amount of data - definitely adding more subs will help with noise in the fainter areas and the background. You might want to dither between subs and combine with pixel rejection to avoid the few hot pixels that are around - assume this is a DSLR image?

 

[Craney]

Personally I think you are on the right track when you start to see the detailed filamentary detail with in the cloud, and you have good resolution there.   Nice one.

[alacant]

Yep, love it. It's made up my mind; it has to be my first target post OAG. Just hoping it can be half as good as this:)

[SlimPaling]

3 hours ago, cfpendock said:

Very, very nice indeed.  The framing is superb.  Maybe the stars are just a tad oversaturated?

But my kind of image...

Chris

Hi Chris ....

Thanks for you nice comments :-)

How might I reduce the stars being oversaturated? Do I take shorter subs but more of them .... or is this a processing issue?

Mike

[SlimPaling]

2 hours ago, coatesg said:

 You might want to dither between subs and combine with pixel rejection to avoid the few hot pixels that are around - assume this is a DSLR image?

 

Hi Graeme ...

I used my APM refractor for imaging.

I have never done any "dithering between subs" or "pixel rejection" .... I will have to look this up!

Mike

[cfpendock]

1 hour ago, SlimPaling said:

How might I reduce the stars being oversaturated? Do I take shorter subs but more of them .... or is this a processing issue?

Sorry, Mike, I am not particularly expert in this, but yes, for sure there are processing routines which would de-saturate just the stars.  

But it is only my opinion that they are " a tad over-saturated".  I am sure others would be happy with them as they are.  It is purely a processing issue, nothing to do with image acquisition, although as others have mentioned, more subs will only improve the image further, particularly in terms of noise and the ability to stretch the data further to reveal more faint detail.

Nevertheless, for the amount of time (less than one hour total), I find your image is remarkable.

Chris

[coatesg]

2 hours ago, SlimPaling said:

Hi Graeme ...

I used my APM refractor for imaging.

I have never done any "dithering between subs" or "pixel rejection" .... I will have to look this up!

Mike

Hi Mike - I meant "what was the imaging camera?" I was looking at your signature and I assumed it was a DSLR, though re-reading the post you say LRGB! D'oh!

Dithering is where the guider moves the telescope a few pixels between every exposure - it has the effect of moving hot pixels, column defects, etc. around in relation to the object you're imaging. This allows you to use software to reject any "outlying" values compared to the median for that bit of sky when you do the image combination (so you eliminate hot pixels, cosmic ray strikes, etc). You'll need more subframes for that to work well (usually 8-10 or more in each channel) but it gets rid of all kind of cosmetic issues (and can deal with satellites, planes and other issues). 

Still, a great image given only 10 min in each channel!