Orion M42 with OMD EM5 and William Optics GTF 102mm

PhilS

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I used my Ioptron IEQ30 to track this beauty. I did not have my lappy with me so all images were unguided and had to be short at 20sec each. Camera set at IS0800 and had a light pollution filter attached as I was imaging from a major city.

I took a total of 60 images and stacked them with Deep Sky Stacker (took an age). Saved out a 32bit tiff and then graded in Photoshop. I used Imagenomic to further reduce the noise.


M42 in Orion - OMD EM5 by philipsavory, on Flickr
 

imahawki

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Aug 12, 2014
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This is an awesome shot. Can you describe a bit more how you set this up? What are the 60 images for? To capture range of exposure or depth of field or some other reason (noise reduction?)? This is all foreign to me.
 

OzRay

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That's excellent, considering how I've read a lot about this and everyone recommends FF cameras as being just about the only way to get such shots.
 

PhilS

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imahawki

The reason for the 60 images is to combine them in a program like Deep Sky Stacker (DSS) to reduce the noise.

When taking astro photo the longer the duration of the exposure the better as you get the best signal to noise ratio. But three things happen. 1. if you are in a city and you shoot too long the image will over expose due to sky fog.. ie the glow from the lights. 2. you can get tracking errors from the mount. 3. you can get planes and satelites going through the field of view.

I did not have time to set up my guide scope ( a little baby scope that sits on the main scope and has a CCD on it that tracks a target star and talks to you laptop and mount.. its like a positive feedback loop), so I had to keep the duration short.

As the duration was short, just 20 secs, I had to boost the ISO but this introduces noise and reduces the dynamic range. So if I take a lot of images and stack them , I can reduce the noise.. it works a treat.

When I am imaging using my AstroCCD, I cool it down to -10degC and usually guide the scope and do 5 minute exposures.. even from from the city. I do narrow band imaging, just detects the hydrogen alpha in the emmision nebulas so light pollution is not an issue.. neither is the full moon.

this is a narrow band of M16.. the Eagle Nebula
.. M16 Eagle Nebula in HA by philipsavory, on Flickr

i hope I explained it some what.

ozray and halfhand.. thanks for the comments :)
 

PhilS

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Thanks Halfhand..narrowband imaging with Hydrogen alpha is a real joy. the camera picks up so much detail.
 
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