Damian noticed yesterday a problem with the size of my images taken with m QHY10 camera – explained in my email to him below. It is quite a learning process, this astrophotography!

Andy

Hi Damian,

I have looked at original images from the M45 picture and you are right, they are smaller than expected:

1948 x 1306 = 2,544,088 pixels – should be 10 megapixels on QHY10.

Looking back at my M101 photo – one of my very first – also 1948 x 1306.
Similarly my photo of NGC7000 = 1948 x 1306 pixels.
Hence I have been producing images of this size all along.

So question is why?
Wasn’t deliberate!

Just checked Nebulosity 4 – but it won’t show my settings at moment for QHY10 without plugging camera in and and that is outside in shed so will need to do it tomorrow or over weekend and find out what is happening.
Perhaps you are right – binning?

(1948 x 2) x (1306 x 2) = 10,176,352 pixels

QHY10 Camera Specifications (from https://www.google.com/search?q=qhy10+specifications&rlz=1C1CHBF_en-GBGB848GB849&oq=qhy10+specifications&aqs=chrome..69i57.5914j0j7&sourceid=chrome&ie=UTF-8):
Sensor: Sony Super HAD ICX493AQA.
Total Pixel Array: 3964 x 2712.
Active Pixel Array: 3900 x 2616.
Pixel Size: 6.02 micrometers x 6.02 micrometers.
Color Method: RGB Bayer Film on CCD.
Readout Noise: 8-10 e-
System Gain: 0.7e-/ADU.
Full Well Capacity: 45,000 electrons.

1948 x 2 = 3896
1306 x 2 = 2612

This seems very close to the 3900 x 2616 listed above in specifications and therefore it seems very likely that 2 x 2 binning is occurring and I must have accidently set this in Nebulosity 4 at some point and not removed it again – at the beginning as affecting all photos I have taken and this would make sense as I did not know what I was doing in Nebulosity then.

Thanks for pointing this out!

Andy

Damian made this comment about this post:

Just like to point out this was a quick process (no more than 10 mins) to give Andy an idea where he should be aiming as he learns the art of processing his images. Also to point out that he needs to investigate his flat frames, his pre-processing and a few other things I spotted when looking through his FIT file.
Damian

He also noted that binning improves sensitivity 3-4x and hence if I do remove binning then my photos will have 4x [see Damian’s comment – should be 2x] resolution at expense of needing 3-4x length exposures to obtain same depth – and as I am not currently guiding this will make it difficult for me to obtain enough data to show nebula regions etc. On the other hand, binning explains lack of detail in spiral arms and other small structures in my images, due to lack of resolution.

So I need to get guiding sorted……!