Stars are reduced in this image and the contrast is enhanced a bit.

Tags:   Milky Way stars astrophoto PixInsight Nikon d7000

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Milky Way: Used Nikon d7000, 24mm equivalent focal length. 2000_20m25s4fr_f:6.3-16mm

Tags:   Mily Way stars astrophoto

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Nikon d7000 Tokina 11-16mm Stacked: 1250 ISO - Exp 29m37s15fr f/4: 12mm (effective 18mm)

Tags:   milky Way stars astrophoto

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I HAVE STARTED A SPRITES GROUP ON FLICKR:

www.flickr.com/groups/_sprites/

PLEASE CONSIDER JOINING.

Reference: spaceweather.com 30 Jun 2014 issue.

SPRITES AND GRAVITY WAVES: The sprite show continues. "Every day this week, I have been able to photograph red sprites shooting up from the tops of thunderstorms 400 miles away in Colorado, Nebraska and Kansas," reports Jan Curtis of Santa Fe, NM. On June 27th he saw something more: "At around 10:30PM MDT, gravity wave clouds developed and intensified through midnight."

"While I could not detect them with my unaided eyes, time lapse video revealed that the waves were moving very slowly to the northeast," says Curtis.

The waves are, literally, the ripple effect of a powerful thunderstorm on the mesosphere some 80 km above Earth's surface. From space, these waves look like a giant atmospheric bull's eye. The green hue comes from airglow, an aurora look-alike that can be seen on very dark nights from any place on Earth.

Although airglow resembles the aurora borealis, its underlying physics is different. Airglow is caused by an assortment of chemical reactions in the upper atmosphere driven mainly by solar ultraviolet radiation. Auroras, on the other hand, are fueled by gusts of solar wind. While auroras are confined mainly to polar regions, airglow makes a luminous bubble that surrounds the entire planet.

The undulations in the airglow Curtis photographed are caused by temperature and density perturbations rippling away from the central axis of the distant thunderstorm. Speaking simplistically, those perturbations alter chemical reaction rates in the upper atmosphere, leading to more-bright or less-bright bands depending on whether the rates are boosted or diminished, respectively.

Inhabiting the upper reaches of Earth's atmosphere alongside meteors, noctilucent clouds and some auroras, sprites and mesospheric gravity waves are true space weather phenomena.

Tags:   Sprite, time lapse, air glow

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By now, you have figured out that I like the night sky; especially when it is dark and clear. This time lapse captures the moon setting as the landscape darkens. Moments later, the Milky Way rises. Total time in the sequence is 135 minutes. Each exposure was 20 secs. Some cars drive down my street before dawn, helping to break the still of the night. Rats!

Tags:   moonset Milkyway stars twilight timelapse Tokina 11-16mm f/2.8

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