Moving terminator study

[spaceman_spiff]

Hi SGL,

I am thinking of spending my next lunar imaging session on just one small section of the Moon on the terminator, taking a stacked image every 3 mins to study the terminator moving across the lunar surface. Why?...I image with a Mak 150 using only a small sensor area meaning a small FoV. I've never got close to finishing a complete mosaic so I thought of this as a different approach.

Has this been done before? I have done a 2-frame animation of Petavius taken 2.5 hours apart.

Dan

[Victor Boesen]

Wow! very interesting animation!!

[RT65CB-SWL]

Very good. I have been meaning to do something like this too. 

[Paul73]

Big difference in 3 mins. Good idea for a project.

Paul

[spaceman_spiff]

I think it will be more satisfying than an incomplete lunar mosaic (plenty of examples in my album!). I would love to see the terminator moving smoothly across the lunar surface...

[spaceman_spiff]

1 hour ago, Victor Boesen said:

Wow! very interesting animation!!

thanks!

[johnfosteruk]

Very good idea, you can even get away with the odd cloud gap if you're doing a long run every 3 mins. Might give it a go myself.

[Demonperformer]

That is an innovative approach. Looking forward to seeing the results. 

[Stu]

12 hours ago, Paul73 said:

Big difference in 3 mins. Good idea for a project.

Paul

I think that was 2.5 hours Paul.

Every three mins should produce a very smooth animation, might even be more than is necessary but I look forward to seeing the results.

I vaguely remember seeing something similar but it may well have been a simulation using a generated 3D image, can't quite recall.

[johnfosteruk]

16 minutes ago, Stu said:

I vaguely remember seeing something similar but it may well have been a simulation using a generated 3D image, can't quite recall.

Perhaps these:

[spaceman_spiff]

That's what I'm going for but with a much smaller FoV. This should allow tiny changes in illumination to become apparent.

[JamesF]

I think it's an excellent idea.  Good luck with it.

James

[spaceman_spiff]

Just done a few calculations...obviously the terminator movement is slow...about 15 days to cover the lunar diameter (31 arcmin)

In about 4.6 hours the terminator will move about 24 arcsec across the FoV (about 1/10th) the total view. That's about as long as I can image for without jeopardising my marriage. I'm aiming for dramatic changes in the shadows of crater rims, central peaks and disappearing lunar features.

Forecast to be clear Friday and Saturday...I'll keep you posted.

[johnfosteruk]

I think Eratosthenes and the Appenines will be a most excellent target on Friday. Lines show the terminator position at 1900 and 2330 respectively.

 

[Astro Imp]

This sounds a most interesting approach, like several others I look forward to seeing the results.

Hope you get some clear for this project.

[spaceman_spiff]

Great responses here - thanks everyone!

I've done a few more calculations and found that if the terminator were a single boundary (between light and dark) it would travel at around 0.0861 arcsec/min which corresponds to 1 of my pixels every 5.69 mins (0.49arcsec/pix). Of course the moving terminator produces shadows at shallow angles that could faster than this so I will image using 3 mins of video separated by 3 minute intervals. I can always split the videos to get even more frames in the final animation...

[Demonperformer]

This is the thing when trying something new. You can calculate it to 4 decimal places of an arc-second (a man after my own heart) but at the end of the day it is always <I'll try this approximation and see how it goes>.

Kein Operationsplan reicht mit einiger Sicherheit über das erste Zusammentreffen mit der feindlichen Hauptmacht hinaus. [No plan of operations extends with any certainty beyond the first contact with the main hostile force.] Helmuth von Moltke. Über Strategie [On Strategy] (1871).

[spaceman_spiff]

7 hours ago, Demonperformer said:

This is the thing when trying something new. You can calculate it to 4 decimal places of an arc-second (a man after my own heart) but at the end of the day it is always <I'll try this approximation and see how it goes>.

Kein Operationsplan reicht mit einiger Sicherheit über das erste Zusammentreffen mit der feindlichen Hauptmacht hinaus. [No plan of operations extends with any certainty beyond the first contact with the main hostile force.] Helmuth von Moltke. Über Strategie [On Strategy] (1871).

Ha ha!

Maybe I'm going a bit ott with the numbers, lets see what how things go...

[spaceman_spiff]

Ok, I'm back inside after imaging the southern region of the terminator (including Tycho, Clavius, and Longomontanus). I did 36 x 5min videos at 60fps. Each video had an interval of 5 mins. Overall time span ~6 hours.

Wind was bad for the first few hours but then improved.

I'm off to bed...there's a lot of processing ahead.

[Pete Presland]

Great idea, looking forward to seeing the results!

[spaceman_spiff]

Done a quick process of the first video (of 36!) and results look good...I've attached the first processed frame. The final animation will probably be a cropped version of this or will show frame edges moving relative to lunar features...haven’t decided yet.

I doing three different process types-light, medium and heavy wavelet stretch. This is the heavy stretch.

 

[Demonperformer]

Looking good.

[spaceman_spiff]

Hi all,

Here's my first attempt at the animation...

I used 31 x 5 min movies at 60 frames/s. I used an interval of 5 mins between each movie capture. Registax 6 was used to align, stack and tweak each frame. The animation captures 6 hours of terminator movement in 3 seconds!

[spaceman_spiff]

I just noticed the tilting due to lunar liberation...glad I didn't correct that.

I also have another set taken the next day as well...processing them now.

[JamesF]

Very nice