October Imaging Challenge (NB) - M16 (Eagle Nebula)

[iceman]

Hi all.

We'd love you to take part in the October Imaging Challenge (http://www.iceinspace.com.au/index.php?id=69,241,0,0,1,0). Please post your images here.

Please ensure all images obey the posting guidelines when you attach them.

While it would be nice if the image was taken in the month of October, it's not essential so feel free to post older images if you're unable to take some new ones.

We look forward to seeing your contributions!

[Itchy]

Hi Everyone

My M16

Date: 6 August 2005
Camera: Canon 300D
Telescope: Meade LXD55 SN10
Details: 114x30sec exposures at ISO1600, prime focus, unguided
Processing: ImagesPlus- Dark, Flat and Bias calibration, DD. Photoshop CS- levels, curves. Noiseware.

[atalas]

Absolutly beautiful Tony ! " Master why can't I snacht the pebble out of your hand ?"
One of the few neb's that looks like Its name sake , the more apeture used the better It
Looks. I've never seen the Pillars of life in It visaully biggest scope I've used on It has been an 18" .

Louie

[Striker]

Woops...posted it in the wrong thread...I blame Robby....lol

[atalas]

Its in the right one Tony ! I remember this shot of yours I love the rich colour and very good detail of the pillars of life .


Louie

[cventer]

Another Eagle Taken last month.... Its getting a bit low to image right now....

A larger version can be seen here:

http://www.dslrfocus.com/eaglecolorlrg.jpg

Scope: Takahashi FS102 at F8
Mount: Losmandy G-11
Camera: SBIG ST-2000XM
Processing: CCDSoft, Registar and Photoshop CS

Best Regards
Chris Venter

[atalas]

Beautiful images Chris ! :jawdrop: and the large version really shows Its beauty .
Chris is the CCD a one shot colour or did you do tricolour ?

Cheers

Louie :thumbsup:

[davidpretorius]

dsahkjh dhhdhd d asd bbbuub bub gooo gaaaa........smack!

thats better, mouth is now working!!!

great work all you guys!!!

the eagle is at the cventer?, where are the pillars of life?

the other night i was in this area and the main central bit seemed to be viewable as a white long ellipse???, it is the only nebula i know of around this section of sky, would that be right?

[cventer]

Thanks Guys.

Its a Tri Color CCD Shot
10 x 6 min LUM,
10 x 4 min RGB Binned 2x2

Regards
Chris Venter

[Striker]

Just beautiful Chris.

Well done.

[Brad Moore]

Hi Chris and Tony,

Nice work from you both again! Well done. You both set a high standard.

Cheers,
Brad Moore

[atalas]

Wow chris a total of three hours of exposure ! did you shoot from dark skies ?

Louie

[cventer]

Dark Sies. What are they ?

No, from bad light pollution in inner suburb of melbourne.

Regards
Chris

[iceman]

Excellent shot Chris. Stunning, in fact!

[ving]

great shot chris! :D

[tornado33]

Hi all
Here is a shot I took some months back.
Its 2 x 15 mins ISO 1600, Baader UHCS, 10 inch F5.6 scope, EOS 300D.
Scott
[IMG]http://www.iceinspace.com.au/forum/attachment.php?attachmentid=5268&stc=1

[atalas]

Very nice shot Scott !

Cheers

Louie

[Itchy]

Aahh!!!

IT's upside Down!! :nerd: :whistle:

Nice shot Scott

I just got one of those Baader UHCS filters. :cool:

Cheers

[Rodstar]

Some great shots guys. Thanks.

[PhotonCollector]

Here's my shot of the Eagle Nebula.

The image was taken using my 8-inch f/6 telescope and the unmodified Canon EOS 300D, hand guided with my 4.5-inch guidescope.

This image is composed of 2 x 5 minute exposures @ ISO1600 and 3 x 10 minutes exposures @ ISO400, a total of about 40-minutes exposure time.

There's a medium resolution verson of the image at http://www.skylab.com.au/pmsa/Messier%2016%20Eagle%20Nebula.html

I think the individual exposure times were too long and that resulted in many of the brighter stars "burning out" and becoming white, oh well, I know for next time.

[atalas]

Very nice image Paul ! well done .

[PhotonCollector]

Hi Itchy,

That's a great image of the Eagle Nebula. I really like the wide field. That's a lot of images to take, over 100 ! wow... and unguided too. Could I ask how the image would look if you did not subtract dark frames and did not flat or bias calibration ?

Paul

[PhotonCollector]

Hi Chris,

Ummm, errrr... isn't your image of M16 mirror reversed ?

[PhotonCollector]

Nice image Scott, that red nebula is really red and the sky black.

[cventer]

Yeah, when I flipped it in photoshop to get it right way up I forgot to flip it horizontally as well.
Regards
Chris

[Itchy]

Ok Paul, you got me intrigued, so I stacked the converted RAWS without calibration. I was rather suprised with the result. There is a little vignetting but it is not overpowering. The biggest difference was in how much faint detail I was able to extract. It was much harder to get anything out of the uncalibrated stack, and even the fine detail in the brighter parts of the nebula is missing.

Conclusion: Calibration is definitely worth it. What's your (and others) opinion?

The Uncalibrated image is on the left

Cheers

[atalas]

Tony, the one on the right looks a lot better but I don't know If I'm seeing It that way because of better contrast . As I go over It I can find the same detail I think but Its probably my inexsperiance again .

[TidaLpHasE]

:)Awsome shots:prey2:

[PhotonCollector]

Yeah, I'd have to say the calibrated image certainly looks better for a number of reasons. I guess the only reason I asked was to see what type of difference there would be in the resulting image. Now I can see for myself, thanks.

Some time ago I made my own CCD camera (the Cookbook 245 with LDC) and of course dark and bias frames were always part of the process. I guess since getting my Canon EOS I had fallen in to the trap of thinking darks, bias frames etc really don't make that much difference with the digital slr. However I can see now that I should be doing darks etc.

Can you subtract darks etc with photoshop ? or do you need to purchase software ?

Thanks.

[seeker372011]

someone will correct me if i'm wrong, no doubt, but you can subtract darks easily with photoshop but dividing flats..that's another matter. Plug ins are available and artificial flats can be constructed but IRIS-free (!!!) or Imagesplus seem to be the answer.

also Maxim DSLR- a stripped down version of Maxim has I believe been recently announced that will do the job

IRIS - is great but you have a big learning curve as its not all that intuitive

[[1ponders]]

JFYI Maxim DSLR is now available. You can download a free 30 day trial. Size is 18mb

[Itchy]

Hi Paul

You can subtract darks in Photoshop, but you need to do it one frame at a time. If you have a full version you can use apply image --> subtract. If you only have elements or a light version of PS, you can do it by pasting the dark on the light and use the difference blending mode. Difference is not a true subtraction, but because your dark should be less than your light, it should do the job.

Flats are another story. There is no operation in Photoshop that perfroms a correct flat division. There are various methods for removing vignetting in photoshop after stacking but I'm not convinced that they do the same job as a good flat.

If you want to go with freeware, there is IRIS (very good but command driven and originally french), or you can try PixInsight (more sofisticated but not intuitive).

I have purchased ImagesPlus and I would reccomend it highly. Using it improved my images immediately. I now use ImagesPlus for RAW conversion, calibration, aligning and combining. All of these processes are automated and easy to learn with the help of training videos that come with the package.

Hope this helps

Cheers

[PhotonCollector]

Thanks, Seeker372011

[tornado33]

Howdy all
I find that I have to be careful subtracting darks with Photoshop, I do use Photoshop but often have to reduce the opacity of the dark otherwise I will get dark coloured spots on nebulosity areas. I find the lazy way out is to do the dark subtraction with reduced opacity (a partial subtraction one could call it), then use the Gradient Exterminator plugin for photoshop to remove most of the vignetting and amp glow. I had a look at IRIS but it looks like it does have a steep learning curve.
Scott

[PhotonCollector]

Hello Itchy,

I have PS full version but I find that the method of subtracting darks does not appear to work quite correctly.

I've downloaded IRIS and am working through that for the time being.

Yes thanks this does help.

[PhotonCollector]

Geeday Scott,

yes that's it ! When I attempted to manage darks in photoshop, i found no problem making an averaged master dark frame. In wide field imaging the dark subtracting is okay but in subtracting dark frames from an image filled with nebulosity, dark holes usually appear in the dark subtracted image.

Possibly the dark holes are where "hot" or "extra noisy" ccd sensor pixels appear on the dark frames, then when you substract these bright pixel values from the image, you end up with black pixel areas in the dark subtracted image.

[tornado33]

Howdy Paul
I have not made a master dark but I guess I should try averaging several darks together and see how that goes :)
Scott

[cventer]

Bear in mind You need to average at least 9 darks to get a decent master dark frame. many of the top CCD guys actualy shoot a minimum of 20 darks....

Best regards
Chris

[Striker]

Can I just use the noise reduction on each image to give me the same result.?????

[cventer]

you can but the result is not as good as an averaged master dark. In built camera noise reduction will subtract the noise it sees in that particular exposure. If you get a cosmic ray strike during that partcular dark you end up with a messed up exposure.Taking several and avergaing gives a better and msoother view of the cameras dark noise.

Using in built darks subtraction also mean you waist valuable imaging time for each exposure while camera does noise reduction.

Regards
Chris

[PhotonCollector]

Yes that's right. Remember the CCD camera days, we used to take lots of darks and average them to make a master dark for that imaging session. I always did the imaging processing so you may have not been aware of that.

In some instances I would do just one dark frame immediately after the image and subtract that, but experience and recommendations by others, certainly showed that images were generally smoother with averaged dark frames.

Another reason for averaging them was that the temperature will potentially change (get cooler) over the period of your imaging session and this means so too will the amount of dark noise generated by the camera. So, if you were to subtract a dark which was taken early in the night from an image taken late in the night, then chances are the amount of dark noise your subtracting is too much - since the camera only generated that amount of noise when it was warmer.

Paul M

[Itchy]

Hi Paul,

I've been doing a bit of research into all this lately. It seems that if you subract a single dark, you may be reducing the dark noise, but you will actually increase the random noise by as much as 41%. At 5 darks the additional noise is around 10%. At 10 it is below 5%. To get to only 1% aditional noise you need to average 50 darkframes.



The latest ImagesPlus Beta has a automatic dark frame matching routine that is specifically designed to take account of the temperature variation in a session. It measures the light frame and scales the master dark before subtracting it. It seems to work very well and in fact many imagers (including myself) are starting to use it with a single master dark made from many darks (>50). The concept is that this "super master" dark can be used for a range of different exposures taken at different temperatures and even at different ISO's. It should be possible to make a few of these master darks that would eliminate the need for ever taking another dark frame.

Works for me (if indeed I can make it work at all :) ).

Cheers

[PhotonCollector]

Hi Chris,

Do Cosmic Rays actually make landfall ? I thought they collided with particles in our atmosphere and created other sub-atomic particles, like Muons, which then make it to the ground and allow us to detect the cosmic ray event ?

Paul M.

[cventer]

They do make landfall. And produce artifacts on CCD Detectors. Although sometimes the same affect is causes by terrestrial background radiation but is still called a cosmic ray hit.

try google "Cosmic Ray CCD" and you will get a truckload of reading on the subject.

regards
Chris