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Old 02-27-2017, 02:20 AM   #496
Kyle
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Getting more and more excited for August 21st looking at your photos Artlav
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Old 03-24-2017, 07:22 PM   #497
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First light test of an AO-7 adaptive optics system for my camera and telescope; it tracked like a champ with 5 minute exposures at the native 2000 mm focal length of my scope, which is quite difficult to do with an LX200 classic fork mount.
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Old 03-24-2017, 11:43 PM   #498
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Quote:
Originally Posted by Messierhunter View Post
 First light test of an AO-7 adaptive optics system
Fascinating, Messierhunter. Is it possible for you to post a comparison with/without the adaptive optics?
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Old 03-27-2017, 04:05 PM   #499
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Originally Posted by MikeB View Post
 Fascinating, Messierhunter. Is it possible for you to post a comparison with/without the adaptive optics?
Unfortunately I didn't acquire images with the AO off during the first night's testing, I just wanted to maximize the time I had with it on. I do have an older image of M51 for comparison, but it's not apples-to-apples. The observing site was the same, and the total integration time was similar, but before the AO unit I took every shot with a .63 focal reducer; shooting at the full focal length of my telescope simply wasn't practical even with autoguiding. The latency and backlash of the drive system of the LX200 makes it virtually impossible to accurately autoguide fast enough at f/10. The AO unit has a response time of a fraction of a second and the very fast guiding rates make it possible to image at the full 2 meter focal length without a focal reducer. I took my older non-AO image of M51 and used bicubic sampling to resample it to the same size as my new higher resolution image of M51. Here's a gif overlay:

http://h.dropcanvas.com/ij5tf/aocomparison2.gif
You can see much more fine detail in the AO version, and note that the dimmest stars in the image are much brighter and sharper in the new AO version as well. Next time I have the AO unit attached I'll do a proper on/off comparison so everyone can see how badly blurred the stars are when using traditional autoguiding vs the AO at this focal length on the LX200 mount.
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Old 04-03-2017, 07:54 PM   #500
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Quote:
Originally Posted by Messierhunter View Post
 First light test of an AO-7 adaptive optics system for my camera and telescope; it tracked like a champ with 5 minute exposures at the native 2000 mm focal length of my scope, which is quite difficult to do with an LX200 classic fork mount.
{image}
All your works are truly great! During my sleep last night, a voice told me the following:

With your new AO-7 adaptive optics system, you are certainly the one in this forum to be able to attempt the Man and Planets challenge: with Venus, Mars, Jupiter and Saturn!




Quote:
Originally Posted by Soheil_Esy View Post
 Man and Venus



{image}
http://0e33611cb8e6da737d5c-e13b5a91...0920939_lg.png
http://spaceweathergallery.com/indiv...pc3ia3m7kgemp0
Taken by Vladimir Scheglov on March 31, 2017 @ Magadan, Russia



Details:

After several attempts we were able to shoot my friend Alexander Korolenko during the rise of Venus. The distance between us was about 3300 m. Shot in the area of ​​the Armanskiy pass, near Magadan. Thanks to Sergey Shibetskiy for the transport.
Camera Panasonic GH2, Rubinar 1000 mm, F10 lens. Frames from video:

Video


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Old 04-03-2017, 08:25 PM   #501
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Quote:
Originally Posted by Soheil_Esy View Post
 All your works are truly great! During my sleep last night, a voice told me the following:

With your new AO-7 adaptive optics system, you are certainly the one in this forum to be able to attempt the Man and Planets challenge: with Venus, Mars, Jupiter and Saturn!
Thank you! Unfortunately the AO-7 system is not well suited for that kind of challenge. You need a bright guide star to use the system, which isn't usually practical at the horizon. The window to capture a planet next to a person at the horizon at that kind of magnification is incredibly short; by the time a guide star is acquired (assuming you can find one) and the system is running the opportunity has probably passed. You're also limited to still images; you have to use an SBIG ST- camera with the system. Even my USB ST-2000XCM has a full frame download time of several seconds.

A more practical method would be to use good old fashioned "lucky imaging" techniques, but this will require compositing the stacked image onto a frame of the horizon since the planet is not stationary relative to the horizon. Atmospheric turbulence at the horizon will be quite severe though as you see in that video, so the gains from lucky imaging are unlikely to reach diffraction limits.
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Old 04-03-2017, 09:06 PM   #502
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Quote:
Originally Posted by Messierhunter View Post
  You need a bright guide star to use the system, which isn't usually practical at the horizon.
Can you then consider the use of a laser as a guide star ?

Edit: Maybe it's not even legal where you live, to point powerful lasers toward the sky...

Last edited by Soheil_Esy; 04-03-2017 at 09:09 PM.
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Old 04-03-2017, 09:36 PM   #503
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Quote:
Originally Posted by Soheil_Esy View Post
 Can you then consider the use of a laser as a guide star ?

Edit: Maybe it's not even legal where you live, to point powerful lasers toward the sky...
The AO-7 system cannot be used with a laser guide star; the type of correction it applies requires the use of a natural guide star. From the AO-7 manual:
Quote:
Originally Posted by AO-7 Manual
 The simplest technique, which we have implemented, uses a high speed steering
device to suppress the wander and hold the star image fixed on the sensing device. A second
level of sophistication is to try to correct the lower level aberrations produced by the atmosphere,
in addition to stabilizing the image, while viewing a star. The ultimate technique, developed by
the military, uses a laser guide star to provide a point-like source high in the atmosphere that
provides enough light to enable accurate sensing of the wavefront, and therefore correction. The
laser guide star approach, however, can only correct the higher order aberrations; the image must
still be stabilized by a tip-tilt mirror viewing the object, not the laser guide star.
https://diffractionlimited.com/wp-co.../ao7manual.pdf
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Old 04-04-2017, 02:19 AM   #504
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Quote:
Originally Posted by Messierhunter View Post
 The AO-7 system cannot be used with a laser guide star; the type of correction it applies requires the use of a natural guide star.
It seems that imaging Jupiter and Saturn might be possible though:

Quote:
Originally Posted by AO-7 Manual
 It cannot improve planet imaging unless a guide star is close by, such as might be provided by a moon of Jupiter.
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Old 04-05-2017, 08:39 PM   #505
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Quote:
Originally Posted by Messierhunter View Post
 The AO-7 system cannot be used with a laser guide star; the type of correction it applies requires the use of a natural guide star.


Quote:
Observing Venus (and Mars) with Adaptive Optics

2004?

Current AO Systems

Require a guide “star” close to the science object.
With a planet like Mars or Venus …
Too big to be used as a guide star itself.
Too bright to allow a nearby star to be used as a guide star (scattered light).
e.g. Attempts to use Phobos (mag 10.4) as a guide star for Mars (mag -2.8) have not been successful.
Laser guide stars don’t help.


Solution

We need an AO wavefront sensor that can work on the extended structure of the image of Mars or Venus (rather than a point source).
For Venus use the 2.3 mm cloud structure or 1.27 mm airglow (or perhaps the sunlit crescent in the visible).
For Mars use the surface albedo features.
We know this is possible because solar AO systems work on extended structure (e.g. solar granulation).


http://www.lesia.obspm.fr/venus-atm/bailey.ppt
One possible solution:

Quote:
Orbiting Laser Beacons for Adaptive Optics Observations of Mars and Other Planets

2004

ABSTRACT.

The use of adaptive optics to correct the effects of seeing is rapidly becoming a standard technique
in astronomical observing and is fundamental to current plans for extremely large telescopes. Adaptive optics
has proved effective for studies of small solar system objects that can be used as their own reference sources.
However, it is much harder to apply adaptive optics techniques to bright planets such as Mars and Venus, because
of the difficulty of finding a suitable reference star that is not drowned out by the intense scattered light from
the planet itself. A possible solution to the problem might be provided by current plans for laser communications
systems. For example, the Mars Telecommunications Orbiter, planned for launch in 2009, will carry a 5 W laser
to beam data back to Earth. This laser system in orbit around Mars will provide a very bright guide star, with
a magnitude ranging from 1.8 to 5.8. Such a guide star is more than bright enough for existing adaptive optics
systems and is in the range needed to support “extreme AO” systems, producing very high Strehl ratios. Used
in conjunction with large ground-based telescopes, this could allow studies of Mars with spatial resolutions down
to a few kilometers and allow the ground-based study of Mars to extend around much of its orbit, rather than
be limited to the time around opposition.

iopscience.iop.org/article/10.1086/423904/pdf
No need to go this far, and too extravagant. Thus, a solution nearer to the surface:


Quote:
Sodium-layer Synthetic Beacons for Adaptive Optics

1992

Using adaptive optics to compensate for atmospherically induced wavefront distortions requires a remote beacon.
In astronomical imaging the beacon can be the object of interest or a nearby bright star.
For a satellite the beacon can be a retroreflector illuminated by a ground-based laser.
Unfortunately, dim stars don't always have bright neighbors.

Synthetic beacons, generated by laser backscatter from the atmosphere, offer a solution to this problem.

These beacons are produced by using Rayleigh backscatter, or scattering by the air molecules, at altitudes below 20 km, or by using resonant backscatter from the mesospheric sodium layer at an altitude of approximately 90 km.

iopscience.iop.org/article/10.1086/423904/pdf
And maybe a simplier solution affordable for the amateur astro-imagers, by firing a 1kHz infrared pulse laser and using plasma emission to paint a beacon at 20 km altitude:



Quote:
Aerial Burton 3D display projects images into mid-air

November 12, 2014

Aerial Burton has demonstrated an aerial 3D display, which can project text and images in mid-air.

"The biggest difference between our technology and other displays is, this is a screenless display. This is the only device that can show text and pictures in mid-air, without using a screen.

"Our motivation for developing this display was that we thought it would be useful in emergencies if text could be displayed in mid-air. What makes our technology different is that, when we considered how we might display such aerial text, we thought of using a phenomenon called plasma emission."

The images are constructed by firing a 1kHz infrared pulse laser into a 3D scanner, which reflects and focuses the pulses of the laser to specific points in the air. The molecules at that point are ionized, and the energy is released as photons. Aerial Burton believes that using this technology in emergencies will aid communication after a disaster, letting people know where to evacuate, or obtain food and emergency supplies.

"When we developed this as a commercial product, as you can see today, we wanted to make it transportable by car, so users can convert any suitable vehicle into a 3D display transporter, and take the display to where it’s needed. We’d like to achieve this by early 2015."

As well as prioritizing transportability, Aerial Burton plans to market the display overseas, to increase recognition of this technology.





http://akihabaranews.com/2014/11/12/...-air-524133246

Video




Last edited by Soheil_Esy; 04-05-2017 at 08:42 PM.
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Old 05-20-2017, 08:31 PM   #506
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Hi!

Milky way taken two days ago on the shore of Bug river in eastern Mazovian voivodeship, Poland. Just ~130km from Warsaw.



I'll be back soon with nearly 180° panorama of the same place. I need to posprocess it

Last edited by Poscik; 05-20-2017 at 08:35 PM.
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Old 06-01-2017, 07:04 PM   #507
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Hi! As I promised, here is almost 180° panorama from that place.

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Old 06-01-2017, 08:59 PM   #508
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Quote:
Originally Posted by Soheil_Esy View Post
 One possible solution:
And maybe a simplier solution affordable for the amateur astro-imagers, by firing a 1kHz infrared pulse laser and using plasma emission to paint a beacon at 20 km altitude:
One of the largest corrections the AO-7 makes is to the scope's own residual periodic error. Even if you could project an artificial guide star, it would either need to ride with the telescope (in which case it will share the telescope's periodic error) or provide its own tracking (in which case it will super-impose any periodic or other tracking error into the image) and neither really gets you to the promised land the way a natural guide star does. For this setup, trying to guide on the extended shape of the planet doesn't help either; if the planet is in the autoguider and the guider is tracking it, then the planet is not on the imaging chip. It's just not really intended for planetary imaging, and you can use lucky imaging with the planets to get near diffraction-limited results already, so adaptive optics just isn't necessary for nearly any application involving the planets.
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Old 07-31-2017, 09:52 PM   #509
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Hi!

My first ever attempt to shot down our friends from M31. My setup for this shot was:

22x120s ISO1600 EOS500D + Canon 70-200L @200mm f/4 + Sky Watcher Star Adventurer

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Old 09-27-2017, 09:32 PM   #510
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Tracking the OSIRIS-REx flyby of earth:
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