OPOD - Melting Telescope Dish

Last updated on September 16, 2023

OPOD - Melting Telescope Dish: A Bizarre Optical Phenomenon

Have you ever witnessed an optical illusion that left you perplexed and amazed? Imagine driving by the Owens Valley Radio Observatory near Big Pine, California, only to see the massive 40-meter telescope dish appearing to droop and melt into the ground like a Dali watch. This mind-bending spectacle was captured by Andrew Kirk on June 6th, and the image has left many wondering about the fascinating atmospheric optics behind this phenomenon.

The Mirage Image: A Surreal Encounter

As Andrew Kirk approached the observatory, he couldn't help but notice that something seemed off about the telescope dish. It appeared distorted and surreal, almost as if it were melting before his eyes. Intrigued, he went back to document this peculiar sight. Armed with only a pocket camera and limited zoom capabilities, Kirk improvised by photographing through one barrel of his binoculars to enhance the zoom. The resulting images, taken from a distance of approximately 2 miles, showcased the astonishing transformation of the dish.

The Dance of Light Rays: Refraction and Deviation

To understand the cause of this mesmerizing visual display, we must delve into the science of atmospheric refraction. Light rays from the telescope dish pass through layers of air at different temperatures, creating a gradient that leads to refraction. When light rays move from a cooler layer to a warmer one, they undergo a slight deviation in their path. This deviation always occurs towards the cooler and denser layer.

Complex Temperature Profiles: Image Shifts and Distortions

Vertical air temperature profiles can be intricate, giving rise to various image shifts and distortions. Let's explore some of the optical phenomena that can occur:

• Looming: When a distant object appears raised up without any distortion. This effect arises when there is a linear fall-off in temperature with height, which is more gradual than usual.
• Sinking: A more severe temperature gradient causes the object to appear lower, giving it a sinking appearance.
• Towering: When a distant object appears vertically stretched, resembling a tower. This distortion occurs when the vertical temperature profile is non-linear.
• Stooping: The reverse of towering, stooping refers to a vertically compressed image caused by a non-linear temperature profile.

Unraveling the Mystery: Warm Air Layers and Temperature Gradients

In the case of the melting telescope dish, the vertical stretching effect can be attributed to an abnormally warm air layer near the ground with a non-linear temperature fall-off as we move higher. This unique temperature profile caused the upper part of the dish to be less stretched or not stretched at all, indicating a more normal linear temperature gradient in the higher regions.

The sighting and atmospheric conditions bore some resemblance to stages of an Etruscan vase sunset mirage or the inferior mirages observed over sun-heated roads. However, it's important to note that this event can be classified as a distortion rather than a mirage since there was only one image of the distant object.

A Glimpse into the Extraordinary

Witnessing the melting telescope dish was truly a rare and extraordinary experience. Optical phenomena like these remind us of the wonders that lie within our atmosphere. They offer glimpses into the complex interplay between light, temperature, and atmospheric conditions.

As Andrew Kirk expressed his desire to capture this phenomenon once again with his better camera in tow, we can't help but wonder what other mesmerizing optical illusions await us in the vast expanse of our sky.

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Melting Telescope Dish

On June 6th Andrew Kirk imaged the 40m circular dish of the Owens Valley Radio Observatory apparently drooping and melting into the ground like a Dali watch. ©Andrew Kirk, shown with permission.

I was driving by the Owens Valley Radio Observatory near BIg Pine, California, when I noticed the 40-meter telescope looked odd. A couple of minutes later I realized I had seen a mirage image of the big dish. So I went back to document it.

Sadly, I had only a pocket camera with limited zoom. I improvised, though, and photographed through one barrel of my binoculars to increase the zoom .inset image.. Both photos are from about 2 miles distant.

Amazingly, as I watched, the dish began to tilt upwards and within a few minutes it was pointing straight up. Had I passed a bit later I would have missed it.

I hope to see this again...with my better camera in tow

Light rays from the dish are passing almost horizontally through air layers at different temperatures. Rays passing downwards (say) from a cool layer to a warmer one are deviated slightly. The direction of the deviation or refraction is always towards the cooler and denser layer.

Vertical air temperature profiles can be complex and produce combined image shifts and distortions.

Looming is when a distant object appears raised up but not otherwise distorted. A linear fall off in temperature with height that is more gradual than normal can produce it. A more severe temperature gradient causes the object to appear lower �Sinking�.

When the vertical temperature profile is non-linear then distant objects can appear distorted. �Towering� is the name for a vertically stretched image and �Stooping� for the reverse.

The telescope dish vertical stretching was likely the result of an abnormally warm air layer close to the ground that had a non-linear temperature fall off with height. The upper part of the dish is less stretched (or not at all) indicating a more normal linear temperature gradient higher up.

The sighting and atmospheric conditions had some resemblances to stages of an Etruscan vase sunset mirage or the inferior mirages seen over sun heated roads. Strictly speaking this one was a distortion rather than a mirage because the latter is technically reserved for when there is more than one image of the distant object.

Note: this article has been automatically converted from the old site and may not appear as intended. You can find the original article here.

Reference Atmospheric Optics

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