First M51 Whirlpool Galaxy

[Carole]

My first attempt at this galaxy.  I was suprised at how small and faint it was.  

I set it up to take 2 hours of subs but it was starting to get light before this finished so only able to use 1 hour 35 mins.

19 x 5 mins subs plus darks, flats and Bias.  
Canon DSLR EOS 450D CLS filter, WO Megrez, guided
DSS and PS

[RobertM]

Guiding looks very good Carole.  It is also a faint target. like most galaxies, but you've done well in capturing what you have with such a small aperture.

Robert

[Carole]

Thanks Robert,

you've done well in capturing what you have with such a small aperture

Ah, so does that mean to do this one justice you need a bigger scope? I was thinking it needed a lot more subs, so would I be wasting my time trying?

N.B. Robert, I used my old mount for this, will try your one out next time.

Carole

[MarkS]

Technically you seem to have everything working there.  The focus looks good and the stars are round which indicates good guiding.

M51 is a very faint object and is almost impossible from a light polluted location.  Also, in my experience, the CLS filter gives galaxies a very strange colour cast.

If you were to do this again from a dark location and without the filter you would be amazed at the difference.

Well done.

Mark

P.S. at http://www.markshelley.co.uk/Astronomy/index2008.html you can see two versions of M51 done with the C11 - to show you what I mean.

[Carole]

Wow, Mark, your reply was VERY informative, many thanks for that, and I can certainly see the difference a dark site makes. 

Learning all the time.

Carole

[Carole]

I've done a re-process using some of the advice I've been given.

Not sure if I've stretched this too far, but it looks more pleasing to me.

[The Thing]

That looks good to me Carole.

My efforts at galaxies seem to fall down when I don't have enough subs for the amount of signal - i.e. with the CLS filter the image is dim even with a 5 minute sub. Also as Mark says, the CLS filter makes the colour balancing tricky, especially in DSS which seems very good at turning out mono from colour subs! I tend to use IRIS for this reason, following Marks excellent tutorial sheet he did for a session at Mikes over a year ago. IRIS is easy once you get in the swing of using it and you can redo steps with different settings quickly as you don't have to do all the processing in one stage.

[Carole]

Thanks Duncan.

I have had a go at Iris once or twice, but it doesn't seem to have an "undo" facility if you do something you don't like (or at least I haven't found one).  

I tried to use that crib sheet too, but one of the functions didn't work so I gave up, might have another go at it when I've more time.  I'm pretty happy with Photoshop, there is so much you can do with it and I'm still learning.  

with the CLS filter the image is dim even with a 5 minute sub

My image was pretty dim too, all you could see after stacking was what looked like a couple of faint blurred stars.  I just stretched the hell out of it.  

I think a processing workshop so we can all get together with laptops and our various software might be a good thing to do.  Or if some are willing do a demo of processes they do.

I'd like to have another go at this with more subs.

Carole

[Mac]

good capture.

[Carole]

Thanks Mac.