New to DSO imaging - DSS help please.

[michaelmorris]

I'm just starting out on what I suspect may be a long road of learning DSO Imaging. I've got a new toy (Canon 1000D) and I'm trying to learn how to use DeepSky Stacker (DSS). After some initial problems I seem to have grasped the basic operations of loading darks, flats, lights etc.

I am however stuck on two issues (1) Comet stacking and (2) RAW images.

(1) I've got some captures of Comet Lulin (20 x 30 sec and 20 x 60 sec with associated darks). I've read through the DSS help file and it talks about having to go into each light frame and centering the alignment point on the centre of the comet. Thus brings me to the problems.

a) How do I center the comet's centre? I can get it close with the mouse, but with no keyboard controls I can't centre the cursor exactly over the comet's centre.

How do I select this position as the alignment point?

2) RAW images. I've worked how to load them in and have used the option on the list marked Use Bayer drizzle algorithmn' in the RAW DPP settings options. Alignment and stacking goes okay, where is the nebulosity. Compared to JPEG files I took at the same time, there is very little blue nebulosity around the stars. I'm presuming I've simply missed out a step or two that will miraculously bring back this buried image data. What am I doing wrong/missing?

[Psychobilly]

Hi Michael,

With the comet stacking , if the exposure is too long and the comets core has "trailed" then it doesn't allow you to select it as the "core" ... found this to my cost with the 3 hours of data from the other night... but at least I got a half tidy movie out of it....

I had thought of "cheating" and adding a "star" to the center of the core in each sub using CS then removing it in the post processing of the stacked image

Billy...

[davelrkn]

Hi Michael

I myself am new to DSLR imaging and can understand the learnng curve with seems very steep at times

If you check is same forum section you willl see a tread "Stacking Comet Images" by George and then look at the reply by Apatchy who does a nice job on explaining the process in DSS.

I have found when stacking Raws in DSS that they are normally very dark when the stacking is completed and is the case for me when using Canon 450d.

It's not until you load them into programs like Photoshop or Paintshop Pro and start making the adjustments with levels,curves ect that they will start to brighten up.

I am still learning myself and there are a lot of Members on this forum with a lot more experience than myself that may like to chime in with other advise.

Hope this helps

Cheers

Dave

[Robd]

Michael,

Couple of points in addition to those above.

1 - When selecting the comet centre hold down the shift key, this allows accurate positioning of the cursor rather than DSS trying to guess where the centre is.

2 - zoom in on screen - centre mouse on comet and scroll - I use the scroll wheel on the mouse, not sure what you use if no wheel. This allows very accurate centring. NB when zooming it centres to where the mouse is.

Rob

[michaelmorris]

Rob

Thanks, your comments were a life saver. Now I can stack comets.

Dave

I have found when stacking Raws in DSS that they are normally very dark when the stacking is completed and is the case for me when using Canon 450d. It's not until you load them into programs like Photoshop or Paintshop Pro and start making the adjustments with levels, curves etc that they will start to brighten up.

I don't seem to be able to brighten them up as much as I want. What workflow do you use to brigthen them up?

[Robd]

Michael,

No problem.

I must admit that I have been struggling myself with Lulin, partially caused by nasty sensor noise on one side of the chip.

Basically the process is s follows:-;

Stack in DSS - with darks and flats, ( just stared experimenting with dark bias and bias ).

either save the image, again either apply dss changes or embeded, as 16bit tiff. Try both to see what gives the best result for you.

Edit saved file or the autosave tiff in photoshop.

I then usually follow MartinB's guides to stretch the image - levels and curves.

Then depending on the image various 'Noel's actions' to remove noise etc.

I do not fiddle with the image within DSS - for stacking I usually follow the recommendations from DSS.

Pushing up the brightness value in the 'Raw file settings' section.

The best bet is to experiment, perhaps to just stack a couple of images to check out best settings prior to stacking all images.

I usually end up trying several different things until I get a final image that pleases me, or I decide that no more can be pulled out and give up.

Hope that helps.

I assume that you will be at the guild hall on the 4th? so I will see you then.

Rob

[michaelmorris]

Michael,

I assume that you will be at the guild hall on the 4th? so I will see you then.

Thanks for the info Rob, that's very useful. Where do i find Martin B's guide?

Yep, I'll be at the Guildhall on the 4th April. (For those not in the know, this is a free public exhibition on astronomy at Worcester Guildhall on 4th April with a free planetarium show. It's all part of our IYA thingy.)

[michaelmorris]

Where do i find Martin B's guide?

Found it!

[Robd]

Michael,

assuming that you have found the guides in the help section I think they are missing the images. It's best to look at his web site www.astropixels.co.uk

Rob

[michaelmorris]

Michael,

assuming that you have found the guides in the help section I think they are missing the images. It's best to look at his web site www.astropixels.co.uk

Rob

Thanks again Rob.