Dark Energy Camera Takes Accidental Gigantic, Magnificent Picture of Comet Lovejoy

Oops! In a happy accident, Comet Lovejoy just happened to be in the field of view of the 570-megapixel Dark Energy Camera, the world’s most powerful digital camera. One member of the observing team said it was a “shock” to see Comet Lovejoy pop up on the display in the control room.

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CrazyNeutrino said:

Dark Energy Camera Takes Accidental Gigantic, Magnificent Picture of Comet Lovejoy

Oops! In a happy accident, Comet Lovejoy just happened to be in the field of view of the 570-megapixel Dark Energy Camera, the world’s most powerful digital camera. One member of the observing team said it was a “shock” to see Comet Lovejoy pop up on the display in the control room.

more…

The image of the centre of the comet has a dark blob. I can’t help wondering if they are seeing the actual shape of the core of the comet. OK, now I’ve looked at the most highly detailed version of the image I’m almost sure it’s an artifact, not the actual shape of the comet core.

The Pan-Starrs camera is bigger, with 1400 megapixels, so I’m not sure what they mean by “most powerful”.

I didn’t even know that this camera existed. More about the Dark Energy Survey and DECam at https://www.darkenergysurvey.org/DECam/DECam_add_tech.shtml

> The optical corrector system is a Wynne-style five lens, two asphere design. It provides a 2.2 degree field of view image at 0.27”/pixel

2.2 degrees field of view is very big for an astronomical camera, but not exceptional. Pan-Starrs has a 3 degree field of view.

mollwollfumble said:

The Pan-Starrs camera is bigger, with 1400 megapixels, so I’m not sure what they mean by “most powerful”.

> The optical corrector system is a Wynne-style five lens, two asphere design. It provides a 2.2 degree field of view image at 0.27”/pixel

2.2 degrees field of view is very big for an astronomical camera, but not exceptional. Pan-Starrs has a 3 degree field of view.

On the other hand, DECam is fitted to a 4 m diameter telescope whereas Pan-Starrs is only on a 1.8 metre diameter telescope.
The Dark Energy Survey will catalog the sky in a 5000 square degree area over 525 nights.
Pan-Starrs, on the other hand, views 6000 square degree area every night. It’s a rapid response camera.
That means that DECam will be able to see objects that are very much fainter than Pan-Starrs.

It’s interesting to compare DECam and Pan-Starrs to the Sloan Digital Sky Survey. The SDSS camera at Apache Point has a 5 degree field of view, through a 2.5 metre diameter telescope. The 9th Sloan SDSS survey covered 14555 square degrees with a 142 megapixel camera.

How many screensavers will that picture end up on?

mollwollfumble said:

> The optical corrector system is a Wynne-style five lens, two asphere design. It provides a 2.2 degree field of view image at 0.27”/pixel

The optical system is very peculiar. This is the best web image of it, see the five lenses:

That makes the Dark Energy Camera an all-refracting telescope? The largest lens has a diameter of 98 cm, making it the second largest refracting telescope in the world, after the Yerkes Observatory refractor with a diameter of 102 cm.

But then what’s that doing inside a 4 metre telescope? Ah, I see, DECam is not an all-refracting telescope as it receives input light from the 4 metre diameter mirror at the back of the Victor M. Blanco Telescope at CTIO.