Moon 21/04/24

[Graeme]

Here's the 96% illuminated Moon from Sunday Night.

It's the Luminance capture of a 300 frame SER video using the recently released SharpCap 4.1. Did a few runs of 300 x L, 100 x each RGB in Mono16 SER files. The ROI was about 3500 x 3500. The frame rate struggled to stay in double figures! SharpCap 4.0 kept freezing on me but the new release 4.1 worked very well. If it had an auto filter offset focus adjustment it would be perfect!

The video frames were stacked in AS3 and saved as .fit files. I've not been able to combine the LRGB .fit files in Pixinsight, apparently they're not the same size! Looks like I need additional tuition! So this is the Luminance capture only.

A not quite full Moon shows the crater rays well and a few crater shadows on the Western limb.

Moon - L_2024-04-21_EL.jpg

[BobH]

Lovely, Graeme!

Great work in creating such an image.

[Graeme]

Cheers Bob

Hopefully it will look even better when I work out how to combine the RGB data!

Graeme

[HansV]

Excellent!

[stuck]

Even cut down to the 256KB upload limit on The Lounge this one looks good. I bet the original is even better!

Ken

[ChrisGreaves]

Here's the 96% illuminated Moon from Sunday Night.

As usual I'm baffled/blinded by the technical process, but as the moon wakes me up around 2am each night I am still fascinated by the phase changes. Hence this annoyingly pedantic point:-

When astronomers use the phrase "the 96% illuminated" I suspect that they mean 96% of the area of the near-sphere that faces us. I think that the moon always has 50% of its surface not illuminated, even were it to rotate on its axis once per hour. That suggests that 4% of the "illuminated side" is not illuminated, which would lead me to believe that one could say that 54% of the moon's surface is not illuminated, and so that only 46% was fully illuminated.

Notwithstanding crater wall shadows and so on; assuming a perfect sphere of rock.

Even 'though I don't understand all the technical stuff, your images, as always, make me think.
Thanks
Chris

[PJ_in_FL]

Even cut down to the 256KB upload limit on The Lounge this one looks good. I bet the original is even better!

Ken

I agree with Ken.

Beautiful, clear and spectacular!

Thank you again for sharing your efforts and abilities.

[Graeme]

When astronomers use the phrase "the 96% illuminated" I suspect that they mean 96% of the area of the near-sphere that faces us.

Correct.

There's a chance you're over thinking this Chris!

Perhaps 14 day Moon would help?

Graeme

[Graeme]

Even cut down to the 256KB upload limit on The Lounge this one looks good. I bet the original is even better!

Ken

Yes, if I reduce the dimensions of the image prior to saving as a 250Mb jpg it displays ok. Quite amazing really!

Try this:

https://drive.google.com/file/d/14QLyd9 ... sp=sharing

Graeme

[HansV]

How do I view a .fit file?

[Graeme]

Ah, yes, sorry about that!

Any of these: https://fits.gsfc.nasa.gov/fits_viewer.html

Gimp is a popular imaging processing programme that is good.

Here's the link again pointing at a .tif file.

https://drive.google.com/file/d/1dhU_yb ... sp=sharing


Graeme

[stuck]

Another application that will open a .fit file is Affinity Photo.

I think this image would look good as a large canvas print. Assuming you have a suitable large blank wall to hang it on. Or maybe mount it on a ceiling??

Ken

[ChrisGreaves]

There's a chance you're over thinking this Chris!

Always!
And the older I get, the more I seem to over-extend what's left of my brain.
Cheers

[HansV]

Thanks for the .tif link - spectacular!

[Graeme]

When astronomers use the phrase "the 96% illuminated" I suspect that they mean 96% of the area of the near-sphere that faces us. I think that the moon always has 50% of its surface not illuminated, even were it to rotate on its axis once per hour. That suggests that 4% of the "illuminated side" is not illuminated, which would lead me to believe that one could say that 54% of the moon's surface is not illuminated, and so that only 46% was fully illuminated.

Also, yes, it is the 96% of the area of the disc that faces us because 100% is a full Moon. 0% is a new Moon when the Moon is being lit from behind. And yes the Moon is always half lit, the half that faces the Sun. (except during an eclipse) But there is no 4% not illuminated or 54% (46%?) not illuminated, it's always 50%. But as the Moon orbits the Earth the size of the illuminated bit that we can see from Earth varies. The Moon takes 30ish days to orbit the Earth and it rotates once every 30ish days too. So a point on the Moon's surface is in daylight for 15 days and in darkness for 15 days.

There is no dark side of the Moon, matter of fact it's all dark!

Graeme

[HansV]

There is no dark side of the Moon

Oh dear, what will Pink Floyd do now?

[BobH]

OK. It's been more than 65 years since I sat in a classroom when the physics of our moon were discussed. I've slept too many times to have any clue.

Why is it that the Earth rotates but the Earth's moon does not? What are the forces that cause one to rotate and the other not to?

[HansV]

The moon rotates around it axis just like the earth does. But because of the gravity (pull) of the earth, the moon's rotation around its axis has become locked to its revolution around the earth, so it always turns the same side towards the earth.

The moon revolves around the earth in about 29.5 of our days. One "day" on the moon is 29.5 as long as one day on earth.

[Graeme]

What Hans said! In fact the gravitational tug between the Earth and the Moon is so strong that as well as causing the Moon to slow it's rotation till it became locked to a rotation/orbit resonance, it will eventually do the same to the Earth causing the Moon to remain in the same position as seen from the Earth! But don't worry, it's not going to happen for a long time!

[ChrisGreaves]

And yes the Moon is always half lit, the half that faces the Sun. (except during an eclipse) But there is no 4% not illuminated or 54% (46%?) not illuminated, it's always 50%.

Right!
As usual, when I go to my secret place very high above the plane of our solar system I can see that every spheroid object that circles The Sun has 50% of its surface illuminated by The Sun.
Regardless of that spheroid's axis rotational speed.

It is only from a self-centred human's point of view that any of the spheroids surfaces can be said to be "less than 50% illuminated".
And from an interesting geometrical point of view, NO spheroid can ever be said to be "more than 50% illuminated" excepting for mountain peaks, crater rims, and civilization's light pollution.
Thanks, Chris