Jump to content

sgl_imaging_challenge_2021_2.thumb.jpg.72789c04780d7659f5b63ea05534a956.jpg

M51 from the heart of industrial Tyneside


Recommended Posts

Managed to get out for a couple of hours last night. I went out with the intention of getting a bit more practice on imaging with the DSLR. I decided earlier to have a go at M51 due to its good placement at the moment.

Spent the first half hour or so calibrating the guiding and fine tuning the focussing first on Capella then on M44. Setup was Canon 40D (with CLS Eos Clip Filter) through a WO FLT110. Meade DSI II Pro guide camera through a WO Megrez 72. Guided using PhD through GPUSB interface to the EQ6 Pro Mount.

Set away wanting a minimum of 20 (3 minute) exposure. I managed to get 14 subs (12 subsequently useful) before the cloud rolled in. Used the rest of the night to get 10 dark frames.

Stacked using DSS tweaks to curves/levels/colour balance in CS2. I am really pleased with the results when you take into account the very heavy light pollution (I live adjacent to and opposite from another ship yard) in the heart of Tyneside.

I hope you enjoy the picture, I did take a look o my machine at work today and it looked terrible, but it does come in at No8 on the new Mr Ed monitor scale, but I like the result on my machine at home.

(edt, sorry yfronto monitor scale not MrED's)

Regards

Steve..

post-13953-133877341158_thumb.jpg

Link to post
Share on other sites

It's very strange the way an image can look perfectly good one's screen at home but when downloaded to the Forum it could be a totally different one. :scratch:

On my screen I can see only a very faint outline of the galaxies and not all that many stars but I'm sure that your original was much brighter so I applied Auto levels in Photoshop, despeckled the image a bit and must say that I think you have quite a splendid widefield capture there. Not only that but the subject is centre frame which cannot be said for my last attempt at M51. :angry:

I'll post a crop of the image for the benefit of others who are seeing a dark picture 'wat like I got'. :(

Cheers

CW

Click as usual.

Link to post
Share on other sites

It's very strange the way an image can look perfectly good one's screen at home but when downloaded to the Forum it could be a totally different one. :scratch:

On my screen I can see only a very faint outline of the galaxies and not all that many stars but I'm sure that your original was much brighter so I applied Auto levels in Photoshop, despeckled the image a bit and must say that I think you have quite a splendid widefield capture there. Not only that but the subject is centre frame which cannot be said for my last attempt at M51. :angry:

I'll post a crop of the image for the benefit of others who are seeing a dark picture 'wat like I got'. :(

Cheers

CW

Click as usual.

Looks good CW. Having spent most of my working life attaining images through various electron and atomic force microscopes, this image manipulation is strangely new to me, the steep learning curve is steep but fun. It's almost the case that the capture is the easy bit, I'm used to methodical prep and only one or two goes to get it right - still, I suppose that's still a good base for any imaging!!!!

Steve..

Link to post
Share on other sites

It still looks very dark on my screen,Steve. Maybe I need a new monitor. :p

If I apply Auto levels in Photoshop to the image I get the result shown in image (i) where looks as if you have captured a Black Hole,left centre frame! :angry:

However,if I just move the grey pointer in Levels slowly to the left I get image (ii) which is much clearer and brighter on my screen. :(

Have a play and see what you come up with.

Cheers

CW

Click as usual.

Link to post
Share on other sites

Unfortunately it's not a black hole but a very large dust spec on the ccd array. I took a good look at it last night and need to vacuum it off rather than anything else. Need to replenish the air bottle I have for the vacuum before I do anything.

The debate is ongoing with the different views on peoples monitors (YFront started a discussion down at SPM's last month and it has raged on ever since). The changes you just made to the M51 image have come through as a very aggressive on my monitor with an extremely bright green noise right throughout the image. Perhaps beauty is not so much in the eye of the beholder, but in their monitor set-up.

Thanks for the suggestions though, this imaging lark is a steep learning curve.

Steve..

Link to post
Share on other sites

The changes you just made to the M51 image have come through as a very aggressive on my monitor with an extremely bright green noise right throughout the image. Perhaps beauty is not so much in the eye of the beholder, but in their monitor set-up.

Steve..

Much the same on my screen in the case of image (i)...... A green bulge from the left towards the centre and the right side of frame has a red tinge.

Image (ii) looks OK,no real colour shift although a bit bright. This was deliberate to bring out detail.

My screen is set at a resolution of 1152 x 864,refresh rate 80 Hertz and Millions in colour setting. Contrast slider all the way to the right and Brightness at 2/3.

The suggestion in your last sentence above is,I'm sure, quite correct. I'll put a new monitor on hold for the moment. :angry:

Cheers

CW

Link to post
Share on other sites

Here's my 2 bob's worth Steve :angry:

Opened it in PS, Duplicated the image, on the duplicate I used the clone and healing brush tools to remove the stars and galaxy, used the colour select tool to select the black spot, inverted the selection so that everything except the black spot was selected, feathered the selection by 1 pixel to blend a bit better, then applied a 4 pixel guassian blur.

I then applied this image to the original using Image-apply image, blending mode to subtract.

This removed the black spot and most of the gradient.

The rest of the colour gradient was removed using a couple of passes of 'colour gradient removal' in Noels Actions.

I then selected the stars and galaxy using the colour select option, inverted the selection to select the background, and smoothed this using Neatimage (one of the blur functions in PS would work too)

A quick curves and levels adjustment to finish, plus another quick background smooth.

Could have pushed the original data further but the jpeg wasn't really having it!

Fabulous FOV and a great capture, especially for the conditions :hello1:

Cheers

Rob

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.