Author Topic: Sun, Moon and planetary photography  (Read 6069 times)

hip17702

  • New to the forum
  • *
  • Posts: 7
Sun, Moon and planetary photography
« on: June 26, 2013, 03:22:07 PM »
Before speaking about the feature itself please allow me to introduce the context. When doing solar photography I use a telescope as objective (will be a 900mm F6 équivalent) with absolutely no communication with the camera. Not a problem as it is possible to focus using the telescope and take pictures with manual mode.

The main problem is air turbulence. Even if the telescope is perfectly focussed on the sun, air turbulence will randomly blur the image, from quite nothing to totally fuzzy. Currently I shoot 60 pictures in a row to get in best cases 5 not too blurred and in the worst case nothing at all. It is possible to monitor the turbulence via liveview, but if you try to shoot at the right moment  :o... it's always too late  >:(.

Maybe will it be possible to use a function like "Motion Detect" that will fire the camera if the image is at its maximum contrast, condition met only with few to no air turbulence? I yes I'm sure all astrophotographers will bless you and your family until the 30th generation  :P. If not we will stop at the 29th  ;D

chris_overseas

  • Moderators
  • Member
  • *****
  • Posts: 234
Re: Sun, Moon and planetary photography
« Reply #1 on: June 26, 2013, 04:16:39 PM »
Have you tried the "steady hands" feature?
EOS R5 1.1.0 | Canon 16-35mm f4.0L | Tamron SP 24-70mm f/2.8 Di VC USD G2 | Canon 70-200mm f2.8L IS II | Canon 100-400mm f4.5-5.6L II | Canon 800mm f5.6L | Canon 100mm f2.8L macro | Sigma 14mm f/1.8 DG HSM Art | Yongnuo YN600EX-RT II

g3gg0

  • Developer
  • Hero Member
  • *****
  • Posts: 3182
Re: Sun, Moon and planetary photography
« Reply #2 on: June 26, 2013, 04:49:15 PM »
is raw video an option? so you can shoot 1000 images and post process using special tools.
Help us with datasheets - Help us with register dumps
magic lantern: 1Magic9991E1eWbGvrsx186GovYCXFbppY, server expenses: paypal@g3gg0.de
ONLY donate for things we have done, not for things you expect!

mageye

  • Senior
  • ****
  • Posts: 296
  • Atheist
Re: Sun, Moon and planetary photography
« Reply #3 on: June 26, 2013, 05:16:01 PM »
Sounds to me like a 'mirror lockup' issue?
5DMKII | 500D | KOMPUTERBAY 32GB Professional 1000x |Canon EF 50mm f/1.8 II | Samyang 35mm f/1.4 ED AS UMC | Canon EF 75-300mm f/4-5.6 III | Zoom H2 (4CH. audio recorder) | Mac OS X 10.9.2 | Photoshop CC | After Effects CC | Final Cut Pro 7

hip17702

  • New to the forum
  • *
  • Posts: 7
Re: Sun, Moon and planetary photography
« Reply #4 on: June 26, 2013, 10:08:02 PM »
Thank you for your answers and suggestions.

Planetary imaging is well possible in video mode: the 60D(a) is able to record a video with a resolution of 640x480 pixels, using 640x480 "real" pixels on the center of the CMOS. Because there is no crop or resizing image quality is excellent and you can record faint details on planetary surfaces. The drawback is you use only 640x480 pixels on a 5184x3456 pixels' sensor.

As sun and moon are far bigger seen from earth than planets, astrophotographers try to use all the sensor surface to picture the sun or the moon in full. Using the 640x480 video will lead to take multiple movies of surface parts, then process the videos to get good pictures, then stick them together to get the full surface. In case of the sun, where events (like a solar flare) are moving in minutes, pictures taken on different time have a different aspect, thus "unstickable" . Using a 1080p video will get the surface in full, but due to cropping a lot of fine details are lost.

So currently the trick is to shoot continuously until the buffer is full, redo several time the process hoping one of the picture in the sequence was taken in steady air. It is a sort of slow fps, short time, high resolution sequence... with random results.

A way to improve the amount of good pictures is to monitor air turbulence. It is possible to do so in liveview, but the time your brain decide the picture is clear enough, order your finger to press the button to shoot... it's always too late. So you try to guess when the air will become steady. Results proove that guessing is not an exact science.

But if the detection can be done via the electronic or via a piece of brilliant code and the shoot is done in the next quarter of a second then the amount of good pictures will improve greatly and will let the astronomer hands available for other concurrent activities.

I hope I wasn't boring you too much with all these details  :-\

a1ex

  • Administrator
  • Hero Member
  • *****
  • Posts: 12564
Re: Sun, Moon and planetary photography
« Reply #5 on: June 26, 2013, 10:14:40 PM »
Without knowing how exactly that turbulence looks like, I'm afraid it's impossible to tell how hard is to program a trigger for it.

You can look at focus graph. Grab the hourly raw video build and try silent pics with best shots option. It will select the best pictures based on Canon's autofocus metric. See if that works.

hip17702

  • New to the forum
  • *
  • Posts: 7
Re: Sun, Moon and planetary photography
« Reply #6 on: June 26, 2013, 10:42:42 PM »
About an example of air turbulence I have a small .mov (64 MB) showing this effect. If it is possible to upload it I can do that ASAP.

I will also look at focus graph function in details. Thanks for the suggestion.

eduperez

  • Contributor
  • Member
  • *****
  • Posts: 111
Re: Sun, Moon and planetary photography
« Reply #7 on: June 27, 2013, 10:58:40 AM »
Just a comment to some suggestions posted here: if I have understood the problem correctly, this issue is not about camera movement (thus neither mirror lock-up or similar features will help), but about the air between the telescope and the sun acting as a distorting lens.

What the OP is suggesting is to monitor the sharpness of the image, using live view, and to fire a shot when a peak of maximum sharpness is reached; this would be quite similar to doing a focus trap using live view.

Hope this helps.

hip17702

  • New to the forum
  • *
  • Posts: 7
Re: Sun, Moon and planetary photography
« Reply #8 on: June 27, 2013, 12:33:04 PM »
Quote
... if I have understood the problem correctly, this issue is not about camera movement (thus neither mirror lock-up or similar features will help), but about the air between the telescope and the sun acting as a distorting lens.

Absolutely. Now I have to do some homework to see if I can link a steady air moment to a peak on the focus graph or any other monitoring function -as soon as all the clouds around my house decide to migrate somewhere else- to have a clue when firing best shots.

In the meantime I will be grateful if anybody has suggestions for monitoring functions (like focus graph) to test, so I will be ready for the next sunny day  8)

vk4tnt

  • New to the forum
  • *
  • Posts: 14
Re: Sun, Moon and planetary photography
« Reply #9 on: August 20, 2013, 02:42:51 AM »
Hi there
There is free image astronomical image processing software called Registax (see: http://www.astronomie.be/registax/ )
May I suggest to take a series of a few hundred full frames and process it with this software. Registax can eliminate out of focus frames automatically.

SpcCb

  • Member
  • ***
  • Posts: 207
Re: Sun, Moon and planetary photography
« Reply #10 on: August 20, 2013, 03:05:20 PM »
I confirm, mid 2013, AutoStakkert!2 + Registax is the best way for planetary imaging processing.

But in case of bad seeing, there's no way to have a good image.