Zdobienie / Decoration

M42 ( NGC 1976) – Great nebula in Orion

Zdobienie / Decoration

M42 ( NGC 1976) – Great nebula in Orion

processing improvement skills in progress. Below you can see a photo
for comparison, that it is really worth improving own skills in image
processing and it does not necessarily have to be done with paid
PixInside, which will do 80% of the work automatically for the user.
You can do the whole process yourself and acquire new skills.
Important itself is that, the picture processed has a reflected
“face” of the author, which is not meaningless in today’s

fact – At that time, when I was catching photons, I didn’t do any
FLAT frame. Common opinion says that flat frames should be done in
the same session as light frames. Making the necessary flat frames at
a different time (the configuration of the entire equipment setting
is different from the equipment configuration for the light frames
made) will cause you to fail.

I am very inquisitive person and I did an experiment. I didn’t have
a flat for lights done earlier, so I did flat frames with same ISO
like light frames at 1st August this year at the PTMA
meeting in Zwardoń. I remembered that my camera frame position was
relative to the tube in only two positions. Perpendicular to the
length of the tube or parallel. I made flat frames for both positions
and used them one by one position successively in the stacking
process. I saw that the flat frames matched almost perfectly with
light frames. The difference between old image processed without flat
can be clearly seen in the pictures below with flat frame.

On the
left, photo taken in April this year and on the right, processed at
09.12.2019 + flats made at 1st August 2019.

M42 / NGC 1976 - comparsion

Does my
experiment contradict popular opinion? In my opinion, yes.
advice: if you do not have flat frames and you have collected great
material earlier, then make a flat frames. Time and place is not
important. It is important that the equipment should be the same and
the configuration of the layout and position should be only close to
how the light frames were made.

At that
time, I was testing the autoguider Mgen Lacerta on this nebula, and
as you can see it did a good job. At that time I did not have a coma
corrector (optical defect correction) as seen at the edges of the
photo. My NEQ6Pro mount was still working on gears (original

For my
new friends on FB, for information:

(NGC 1976) – Great Nebula in Orion – The brightest nebula on the sky
located in the Orion constellation, south direction from Orion belt.
The diameter of the nebula is 30 light years. The distance from Earth
is 1344 thousand light years.


Photographs (March 2019) made in Zwardoń. A standard place of meetings of the Polish association of astronomy enthusiasts – Katowice dep.
Equipment: Canon EOS 6D, Sky-Watcher 200/1000 [mm] on the NEQ6 Pro. and Lacerta autoguider.

  • Stack: APP (44 best frames),
  • Processing: GIMP v2.10.14 + add-ons (Linux),
  • Lights: 44 x 38[s], ISO-1000; 30.3.2019,
  • Flats: 22 ISO-1000; 01.8.2019,
  • Bias: 20 ISO-1000; 02.8.2019


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