ASTRO: M42

My first attempt at M42.

William Optics Z80, motorized EQ2 mount.
stack of 6 images, total exposure 6 minutes, 30 seconds.
EOS350D, prime focus.

--
Martijn
10" LX200GPS
William Optics Z80, Coronade PST
www.xs4all.nl/~martlian

Martijn, nice one! stayed up late?
Good colors.
Looks like you have a alignment problem or is it caused by windgusts?

reg
Dirk

"md" wrote in message
ll.nl...
My first attempt at M42.

William Optics Z80, motorized EQ2 mount.
stack of 6 images, total exposure 6 minutes, 30 seconds.
EOS350D, prime focus.

--
Martijn
10" LX200GPS
William Optics Z80, Coronade PST
www.xs4all.nl/~martlian

Hi Martijn

Nice first attempt

let me make a few suggestions:

1) it looks to me that your focus is a bit soft. if you aren't using a
motorized focuser and can fit one in your budget, you may find that it is
easier to get good focus using one

2) even without an electric focuser if you can measure the FWHM or HFD of an
unsaturated star in software and use that information to help you gauge the
sharpness of focus, you will get better results.

3) the stars are elongated in the 10 oclock-4 oclock axis. That has a vector
that is strong in the north-south (Declination) axis indicating you have
alignment issues potentially. If you did not I recommend using the Drift
Alignment method to check your polar alignment. With your short exposures
you really don't have to let the drift run very long but it is important
that the star not move any perceptible amount in the 30 seconds of your
exposures. Maybe run 3 minute drifts looking for non-movement of the stars.

4) the dark side of your histogram is clipped: that gives you a pure black
background. But it also obliterates the faint nebulosity.

I have no experience using the 350D type cameras so I am not sure of what
controls you have available to avoid histogram clipping but in my experience
it is always something to avoid.

I was looking at the histogram to try to understand why the stars were Teal
colored instead of white. with the left-side of the histogram clipped it is
difficult to gauge how well each of the three channels have their histograms
aligned.

You have a good start and making a few small improvements will make your
next attempt quite a bit better in my view.

Orion is a tough target to do well. I have never made an image of it that I
really like well.

"md" wrote in message
ll.nl...
My first attempt at M42.

William Optics Z80, motorized EQ2 mount.
stack of 6 images, total exposure 6 minutes, 30 seconds.
EOS350D, prime focus.

--
Martijn
10" LX200GPS
William Optics Z80, Coronade PST
www.xs4all.nl/~martlian

richard, thanks for the comments.

about alignment: I did not do any drift alignment, I just roughly pointed my
eq2 mount at polaris..... really, which is why I was very content about
this attempt.
the eq2 mount is motorized but tracking is not very good or stable.
I am planning to mount my Z80 on my LX200, with the proper balancing, that
should be much better setup.

--
Martijn

"Richard Crisp" schreef in bericht
...
Hi Martijn

Nice first attempt

let me make a few suggestions:

1) it looks to me that your focus is a bit soft. if you aren't using a
motorized focuser and can fit one in your budget, you may find that it is
easier to get good focus using one

2) even without an electric focuser if you can measure the FWHM or HFD of
an unsaturated star in software and use that information to help you gauge
the sharpness of focus, you will get better results.

3) the stars are elongated in the 10 oclock-4 oclock axis. That has a
vector that is strong in the north-south (Declination) axis indicating you
have alignment issues potentially. If you did not I recommend using the
Drift Alignment method to check your polar alignment. With your short
exposures you really don't have to let the drift run very long but it is
important that the star not move any perceptible amount in the 30 seconds
of your exposures. Maybe run 3 minute drifts looking for non-movement of
the stars.

4) the dark side of your histogram is clipped: that gives you a pure black
background. But it also obliterates the faint nebulosity.

I have no experience using the 350D type cameras so I am not sure of what
controls you have available to avoid histogram clipping but in my
experience it is always something to avoid.

I was looking at the histogram to try to understand why the stars were
Teal colored instead of white. with the left-side of the histogram clipped
it is difficult to gauge how well each of the three channels have their
histograms aligned.

You have a good start and making a few small improvements will make your
next attempt quite a bit better in my view.

Orion is a tough target to do well. I have never made an image of it that
I really like well.

"md" wrote in message
ll.nl...
My first attempt at M42.

William Optics Z80, motorized EQ2 mount.
stack of 6 images, total exposure 6 minutes, 30 seconds.
EOS350D, prime focus.

--
Martijn
10" LX200GPS
William Optics Z80, Coronade PST
www.xs4all.nl/~martlian

"D van den H" schreef in bericht
bel.net...
Martijn, nice one! stayed up late?

not really, I shot these at about 1am. Orion was still quite low in the sky.

Good colors.
Looks like you have a alignment problem or is it caused by windgusts?

I did a VERY rough alignment, and yes it was very windy.