M51 Whirlpool Galaxy LRGB

[Carole]

Taken from Cairds Campsite 26-4-14

LRGB with Atik314L and ED120 on HEQ5
900 x 4 + 600 x 4 luminance
RGB 6 x 300 secs each binned x 2
Stacked in Astroart and processed in Photoshop

Could do with more data, but was pleased to get a complete image at least before it clouded up.  First proper attempt at binning RGB which did save time.  

[MarkS]

Carole, that's looking really good!  You've managed to go quite deep with your 3 hours of total integration time.
The Atik looks well matched to ED120.

It was certainly a very good sky on Saturday. A dark sky like that is ideal for RGB acquisition.  I guess there was no need for a light pollution filter.  When I got home from the Herstmonceux visit I registered an SQM reading of 21.15 which is very close to the 21.2 highest reading I've ever recorded at home.  But I was too tired to begin imaging. 

Reading your other thread, it sounds like you had a very succesful trip overall.

One question I have regards the brighter stars, which have a kind of "diamond" shape: which reducer/flattener are you using?

Mark

[Carole]

Thanks Mark. 

which reducer/flattener are you using?

Actually I didn't use a flattener or reducer at all.

Do you think I should have as the field looks quite flat to me? 

I did't want to use a reducer on this occasion as I didn't want to reduce the galaxy size, this is full frame with a slight trim of the edges.  But next time I will use the reducer and see what difference it makes.

Carole

[MarkS]

You did the right thing in not using a reducer in order to keep the galaxy size large.

I was just wondering what may have caused the slight diamond shape to the bright stars.  It's not an objectionable effect (being a Bananascope owner I'm used to square stars) - I just wondered what causes it.

[Fay]

Thats come out really well, gives me hope with galaxy sizes using the 120

[Carole]

Thanks Fay. 

Carole

[RobertM]

That's quite a good effort Carole, you must be very pleased with that.

The stars are showing a bit of colour change top to bottom - is there a slight alignment issue in your stacking if the RGB ?

[Carole]

Thanks Robert

The stars are showing a bit of colour change top to bottom - is there a slight alignment issue in your stacking if the RGB ?

Yes you're right Robert.  Normally I use Registar to align the filters but for some reason it would not recognise the RGB files so I had to do it manually and it wasn't easy.  I should probably go back and try it again when I am less tired.

One of these days I will get my processing right FIRST TIME!!!

Carole

[Carole]

Version 2.
I managed to get Registar to accept this RGB files this time by re-saving them in Photoshop, but it would not accept them straight from Astroart.
Also some people commented the image was too pink - which it was.

[JohnP]

Colour balance looks a lot better. So did you get yourself another 314L after selling me yours? Confused? John

[Carole]

So did you get yourself another 314L after selling me yours? Confused? John

I was waiting for some-one to notice that and I guess you'd be the most likely to.  Yes I decided I wanted to get a smaller chip for doing galaxies and small stuff as galaxy season is a bit of a non starter for me with the 383.  Yes I know people will go on about resolution, but I just feel I can get better definition and focus if the object is closer in anyway and as you know the Atik314 is a really good camera.  I bought an atik16i but decided in the end to get a 314 and re-sell the 16i.  

It certainly seems to have paid off as far as I am concerned.  Also now I have a WOZS71 with the reducer on I can probably get a lot more in the FOV than I could when I bought the original 314.  I am also much happier with the flat field which i have problems with with the 383 and also flats are easier, so will see how it goes.

Doing a lot of buying and selling, as Robert says, you can buy to try out and sell if you change your mind.  Thank goodness for UKABS and also the astro forums as you can often buy from people you know as I did with both the 383 and 314 & 16i come to that and already have a buyer lined up for the 16i.  I even funded the new HEQ5 from selling stuff I no longer use.  

Carole (AKA Delboy  )

[Carole]

You know what it's like when you are never satisfied, well I wasn't happy with the detail in the core, so I went back and did a new luminance by combining the 900sec and 600sec combined stack with just the 600sec stack to drag more detail out of the core, and now I think I am much happier with it, so this should be the final version.

[MarkS]

That's looking much better.  The colour balance is improved and there is more detail.  I think the background should be a bit blacker - it looks blue and noisy on my monitor.  I would also tone down the colour saturation but that's a matter of personal choice.

Mark

[Carole]

Thanks Mark, I'll tone down the background a little but it's a fine balance between doing that and losing some of the faint nebulosity.  Plus I seem to have a bit of chromatic aberration which I don't understand as this is supposed to be an APO scope, so I'll deal with that at the same time.  So it will be version 3 with a tweak.

Some-one on another forum suggested I didn't bin the RGB because of the detail in the red in particular, so I might add to this at a later date and see if it makes any difference.

Carole