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M42 wide 'n' deep!

Eddie

By Eddie
in Imaging - Deep Sky

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Eddie

Eddie

Posted
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Another from over the xMas and new year period. T'was just a quickie but was pretty shocked at how much there was in there!

Details: Borg 77EDII + DGL Reducer + Art11002 + Astronomik Ha. 8x600s + 5x120s (1hr 30min)

Hope you all like it,

Thanks for looking

Eddie

(Click on the image for a bigger one)

M42_small.jpg

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Eddie

Eddie

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Hi Everyone,

Thanks for all the great comments :)

Is it the camera, of the fact that your shooting at F/4.3 which is making the huge difference do you think Eddie?

Hi Richie, the Borg is actually at f5.6 (The DGL reducer is only a 0.85x reduction, can't afford the £600 for the F/4 reducer atm) Though the fast you go the more data you gather in a shorter period of time.

As to the comments of QE, there is far too much read in to QE and it does not make a huge amount of difference (had an interesting chat with Steve Chambers about this recently) One thing that does make a difference is longer subs, a 10min sub is now a short sub for me! This builds up better signal to noise, which lets you push the image further.

TJ, I'll see what I can do when I am on the Mac tomorrow. 8)

Cheers,

Eddie

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MartinB

MartinB

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Hmm, not sure about the QE not making much difference but having invested in a QSI532 I would have to say that! The QSI is more sensitive than an H9 which itself was no slouch. Your Artemis does have bigger pixels though which should help. I can see that pixel size may have as much, if not more impact than QE but I can't see how the QE isn't actually quite significant.

What does Steve say about it?

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Eddie

Eddie

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Steve said the same as what I posted, basically. I think what you need to bear in mind about QE is that the sensitivity of the camera remains the same, you just get to keep more of the photons that land on the sensor. The SBIG 402 I had, had 9nm pixels (like the artemis) it captured the same about of data, except it was just smoother (better SNR) Does that make sense?

Eddie

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MartinB

MartinB

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Not sure I understand Eddie. My understanding of QE is that it relates to the proportion of photons which are converted into charge held by the pixel, this in turn is converted by the ADC into analogue signal. It's signal that we are after.

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narrowbandpaul

narrowbandpaul

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two things affect the sensitivity of the pixel... pixel size or area, and QE

the area dictates the number of photons per second arriving on the pixel.

QE dictates the number that are then recorded. (create e-h pairs)

thats my view.

paul

and that KAF3200ME certainly is sensitive (85% Ha?....wow!)

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Darth Takahashi

Darth Takahashi

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I agree with Paul, if the QE was 100% then every photon would result in an electron being kicked out of the CCD well.

The area question is more interesting, yes more photons arrive on a larger pixel (photons / sec) but does this make any real difference? The reason I ask is because the photons arrive randomly? Therefore, to measure the rain falling on my roof I don't need to measure all of it just a representative sample of it.

However, there is definitely a trade off in pixel size versus sensitivity and image resolution.

Neil.

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