Stellar Focus

[Domenec Reynolds]

Heres what Olympus says about the feature, "Starry Sky AF, which is new for the OM-D E-M1 Mark III, is a feature that will revolutionize the world of astrophotography. In the past, photographers have traditionally relied on manual focusing. A new algorithm was developed to offer accurate focusing even on the tiniest stars shining in the night sky, enabling ultra-high-precision autofocusing that has been admired even among professional astrophotographers. There are two modes in Starry Sky AF. Speed Priority mode (default setting), which prioritizes focusing speed and complete AF operations in a short period of time. Thanks to the powerful image stabilization, this feature makes handheld astrophotography possible using a wide-angle lens. Accuracy Priority uses a fine-tuned focus scan and is effective for shooting specific stars with telephoto lenses."

With Starry Sky AF engaged, the camera locks focus on the stars by pressing the AEL/AFL button on the rear of the camera. It maintains this focus until the camera is turned off or if you switch lenses. The feature is easy to access from within the Super Control Panel. The two different modes (Accuracy Priority and Speed Priority) are available in the Gear Menu (A4).

Once you've composed your shot and enabled Starry Sky AF, you press the AEL/AFL button. The message, "Starry Sky AF is Running" appears on the LCD. The camera then begins the process of trying to lock focus on the stars. I typically use the 3x3 or 5x5 target point and ensure that it is positioned in an area of the frame where the stars are brightest. Acquiring focus usually takes about 5-10 seconds when set to the Accuracy Priority Mode.

In the time that I have had the E-M1 Mark III, I have been out several times to shoot the night sky under a variety of conditions, including thin cloud cover. Starry Sky AF was able to achieve focus each time (sometimes it takes more than one attempt), and maintain that focus throughout the session.

As originally deployed, TESS captured data every two minutes, a frequency sufficient to detect exoplanets but insufficient to gather detailed data on the incidence of stellar flares affecting those planets.

The James Webb Space Telescope, launched in December, is poised to further probe these questions, MacGregor and Howard said. In addition to seeking information about the earliest stages of the universe, it will look for atmospheres on exoplanets, aiming to determining what kind of atmospheres they have and whether they might support life.

The above comment assumes you are talking about the SW rotator that screws onto the focuser drawer tube. An alternative that might work would be a rotator fitted between the flattener and the camera, which could be used with suitable spacers to achieve the 55mm backspacing requirement.

Looking at Tomatobro's image above it seems my Stella Mira "adjustable flattener" puts the optical elements further away from the drawer tube than the dedicated SW flattener, hence why I had very little in travel remaining, don't know if that's the same with the non adjustable version or which one you have. As mentioned by Elp probably no need for a rotator if you are using the 2" push fit connector as you can lock it in any orientation

However, I believe it depends which model of the 72ED you have. There was an older version with a shorter draw tube that, if I recall correctly, could not use the rotator since it didn't have enough travel distance to achieve focus. If you have the later version (which TomatoBro shows in his image) - which is the version I have - then it will be fine. You'll know it because it has that handy black label saying to connect the 360 degree rotator

I have both the Stellamira flattener you have linked, and the skywatcher 0.8 reducer with a rotator for each. They are the Skywatcher rotator and one from RVO , and I'll be honest with you, they are both terrible. Whilst you can rotate the camera, it introduced horrible tilt into my system which I had already spent an age removing (and not wholly successfully either). Rotating the camera undid all that hard work, since the they essentially acted like a tilt plate, and in the end, whilst I had the rotators, I gave up using them. I never got my tilt issue fixed again. Others may have had more success with them, but I really did not.

for a screw on type you will need to remove the nosepiece and other items as per the OVL version FF. the Genuine Skywatcher is a screw on type -pro/skywatcher-85x-reducerflattener-for-evostar-72ed-pro.html

I have the older long tube version of the SW 72ed and had the ovl flattener which is basically the Stella mira one and use the RVO rotator which was excellent on my scope and so much better than the SW one. I had about 5mm of focus tube showing and able to achieve focus.

I have the older long tube version of the SW 72ed and had the ovl flattener which is basically the Stella mora one and use the RVO rotator which was excellent on my scope and so much better than the SW one. I had about 5mm of focus tube showing and able to achieve focus.

I always do my setup tests in daylight. I aim the scope at the top of a distant tree, set the camera to a very short exposure and see what I get. If the scope is a total unknown back focus wise I improvise something without all the reducers etc just to get an idea of what the measurement is. The cardboard tube from the inside of toilet rolls can be useful for this. It excludes the light and you can slide it in and out watching the monitor till a rough focus position is found then mark it with a pen. Now I can start putting together spacers etc.

This photo shows the artistic rendering of the black hole LB-1. A Chinese-led research team has discovered a surprisingly huge stellar black hole about 14,000 light-years from Earth -- our "backyard" of the universe -- forcing scientists to re-examine how such black holes form. The team, headed by Liu Jifeng, of the National Astronomical Observatory of the Chinese Academy of Sciences (NAOC), spotted the black hole, which has a mass 70 times greater than the Sun. Researchers named the monster black hole LB-1. (Xinhua)

BEIJING, Nov. 28 (Xinhua) -- A Chinese-led research team has discovered a surprisingly huge stellar black hole about 14,000 light-years from Earth -- our "backyard" of the universe -- forcing scientists to re-examine how such black holes form.

The Milky Way galaxy is estimated to contain 100 million stellar black holes -- cosmic bodies formed by the collapse of massive stars and so dense even light can't escape. Until now, scientists had estimated the mass of an individual stellar black hole in our galaxy at no more than 20 times that of the Sun.

The team, headed by Liu Jifeng, of the National Astronomical Observatory of the Chinese Academy of Sciences (NAOC), spotted the black hole, which has a mass 70 times greater than the Sun. Researchers named the monster black hole LB-1.

"We thought that very massive stars with the chemical composition typical of our galaxy must shed most of their gas in powerful stellar winds, as they approach the end of their life. Therefore, they should not leave behind such a massive remnant. LB-1 is twice as massive as what we thought possible. Now theorists will have to take up the challenge of explaining its formation."

Until a few years ago, stellar black holes could only be discovered when they gobbled up gas from a companion star. This process creates powerful X-ray emissions, detectable from Earth, which reveal the presence of the collapsed object.

The vast majority of stellar black holes in our galaxy are not engaged in a cosmic banquet though, and thus don't emit revealing X-rays. As a result, only about 20 galactic stellar black holes have been accurately identified and measured.

To counter this limitation, Liu and his team surveyed the sky with China's Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), looking for stars that orbit an invisible object, pulled by its gravity.

This observational technique was first proposed by the visionary English scientist John Michell in 1783, but it has only become feasible with recent technological improvements in telescopes and detectors.

After the initial discovery, the world's largest optical telescopes -- Spain's 10.4-m Gran Telescopio Canarias and the 10-m Keck I telescope in the United States -- were used to determine the system's physical parameters. The results were fantastic: a star eight times heavier than the Sun was seen orbiting a 70-solar-mass black hole every 79 days.

The discovery of LB-1 fits nicely with another breakthrough in astrophysics. Recently, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo gravitational wave detectors have begun to catch ripples in space-time caused by collisions of black holes in distant galaxies. Intriguingly, the black holes involved in such collisions are also much bigger than what was previously considered typical.

3a8082e126