Orion Nebula

[twelly27]

Hi All

The first image is basically my first stacked image of The Orion Nebula, im just wondering whats peoples take is? i stacked all 49 pictures at 5 seconds, i dont understand how why the stars in the middle are that bright, im also wondering if i do more pictures to start with and stack like 30 mins of 5 second exposures will this give a better result all round or does it not work like that?.

The second picture is all 10 pictures i took at 10 seconds bit more happier with this one.

Regards

Chris

03-13-2013 final.TIF

[Knight of Clear Skies]

What camera and iso settings did you use please? My first thought would be to try reducing the iso setting.

[lensman57]

Hi All

The first image is basically my first stacked image of The Orion Nebula, im just wondering whats peoples take is? i stacked all 49 pictures at 5 seconds, i dont understand how why the stars in the middle are that bright, im also wondering if i do more pictures to start with and stack like 30 mins of 5 second exposures will this give a better result all round or does it not work like that?.

The second picture is all 10 pictures i took at 10 seconds bit more happier with this one.

Regards

Chris

Hi Chris,

Before I start let me tell you that I am a beginner in AP but I do have photographic experince. M42 has a very large brightness range and quite a few very bright stars in the core as you have discovered. One set of exposures will not give satisfactory results, you would need one set for the core and at least one set for the nebula itself. you can process these is DSS separately and then combine them in PS to extract the masimum detail out. There are tutorials on the net, Astropix I think but I maybe wrong, detailing how to combine the two layers.I have also read that you can actually create two different photos from the same file, one with the nebulasity showing and the other with the core correctly exposed and then combine them using layers in PS as per instructions. Hope that this helps.

Regards,

A.G

A.G

[twelly27]

Hi Chris,

Before I start let me tell you that I am a beginner in AP but I do have photographic experince. M42 has a very large brightness range and quite a few very bright stars in the core as you have discovered. One set of exposures will not give satisfactory results, you would need one set for the core and at least one set for the nebula itself. you can process these is DSS separately and then combine them in PS to extract the masimum detail out. There are tutorials on the net, Astropix I think but I maybe wrong, detailing how to combine the two layers.I have also read that you can actually create two different photos from the same file, one with the nebulasity showing and the other with the core correctly exposed and then combine them using layers in PS as per instructions. Hope that this helps.

Regards,

A.G

A.G

thats what i was after unfortunately for some reason i cant use photoshop even after downloading the free one but ive made a note of what you have said and if i can get onto photoshop ill give what you say ago only problem is clear sky haha!

[twelly27]

What camera and iso settings did you use please? My first thought would be to try reducing the iso setting.

i think the setting was the highest the camera would go, once i get clear sky im going to try that your not the first person to suggest that to

Regards

[Knight of Clear Skies]

Generally speaking, you want to use the lowest iso setting which shows up the image. Higher iso numbers boost the signal, but increase noise, and do not increase the actual sensitivity of the camera. You might find this thread helpful.

I think a lot of the members here use iso 1600 or 800 as a baseline, but it depends on the camera model (some are too noisy at 1600) and surface brightness of the target. As lensman57 says, sometimes exposures at different sensitivities are necessary. In the case of the Orion nebula, the stars of the trapezium are very bright while the nebulosity is much fainter.

Hopefully a more experienced imager can weigh in and check I'm not saying anything misleading here.

[lensman57]

thats what i was after unfortunately for some reason i cant use photoshop even after downloading the free one but ive made a note of what you have said and if i can get onto photoshop ill give what you say ago only problem is clear sky haha!

I have been sat here all night waiting for the cold clear night that was promised, nothing but clouds.

A.G

[StuartJPP]

I have been sat here all night waiting for the cold clear night that was promised, nothing but clouds.

A.G

Give them a break, they got it 66.667% right, out of the cold, clear and night they predicted, we did get the cold and the night

[Rommel]

thats what i was after unfortunately for some reason i cant use photoshop even after downloading the free one but ive made a note of what you have said and if i can get onto photoshop ill give what you say ago only problem is clear sky haha!

Do you use Lightroom?

DSS is able to stack multiple ISOs into one image. I did that using same exposure time at 10s at F:2.8 and stepped ISO from 400 to 6400. Worked well. After only editing in Lightroom you could do nice pictures from the 32 bit TIFF from DSS. No need to do layers or use PS. The 32 bits TIFF contains all the range. It is like a HDR.

/stefan

[ollypenrice]

5 seconds is plenty short enough to get the Trapezium stars. I used 11 second subs with a faster scope and camera. What you need to do is manage the stretch so that you don't blow the cores, but first you'll need Photoshop or GIMP, perhaps. I don't know GIMP but it's free.

Here's a tutorial on how to stretch. http://www.middlehillobservatory.co.uk/articles-primers/Levels%20and%20curves.htm

What you really need now are some longer exposures as well. Here's how to combine them. http://www.astropix.com/HTML/J_DIGIT/LAYMASK.HTM

It is, in fact, very rare to need separate exposure lengths in AP. In six years I've used them just three times. Usually multiple stretches of the same data can give you the dynamic range that you need.

Olly