About this project
This was a short test, working with a new Narrowband light pollution filter. Narrowband filters are specialty tools that only allow a narrow range of specific wavelengths to pass through. In this case, I was in a heavily light-polluted area and I wanted to isolate and capture light emitted by specific elements or gases in celestial objects, such as nebulae, even in the presence of light pollution or moonlight.
What is light pollution?
In the vast expanse of the universe, objects emit light across various wavelengths. As astrophotographers, our primary focus is on capturing the visible portion of the light spectrum, which allows us to create captivating color images of celestial objects. These colors are typically found within the range of 400 to 700 nanometers (nm). Specifically, violet and blue light reside in the 400-500nm range, green and yellow light in the 500-600nm range, and orange and red light in the 600-700nm range. Ideally, we would prefer to photograph these deep sky objects under dark skies, where we can capture all the colors within the visible light spectrum, undisturbed by any light pollution.
Four main sources of city light pollution
Regrettably, light pollution poses a challenge in (sub)urban areas. Let’s explore the four main sources of light pollution: mercury lights, low-pressure sodium lights, high-pressure sodium lights, and LED lights. Mercury lights are commonly found in traffic lights and neon signs, emitting light at wavelengths around 400nm, close to 550nm, and at 575nm depending on the color. Low-pressure sodium lights, found in some older street lights, emit light at a specific wavelength of 585nm. High-pressure sodium lights, often seen in newer street lights and industrial areas, produce an orange glow with light ranging from 550nm to 650nm. LED lights, increasingly used in residential and industrial areas due to their efficiency, emit light across the entire visible spectrum, contributing to the prevalent white glow in many city skies.
Light pollution is harming our environment, wildlife habitats, and our quality of life.
Imagine not having to drive hours to a dark sky area? Imagine stepping outside your urban/suburban home and seeing a star-filled sky.
The good news is, the solution is as easy as screwing in a lightbulb. Light pollution is something we can all help erase, in our homes and backyards, the parks that we play in, and the cities and towns we call home.
- LEDs and compact fluorescents (CFLs) can help reduce energy use and protect the environment, but only warm-colored bulbs should be used.
- Dimmers, motion sensors, and timers can help to reduce average illumination levels and save even more energy.
- Outdoor lighting fixtures that shield the light source to minimize glare and light trespass help prevent light pollution. An illustrated guide to acceptable vs. unacceptable types of light fixtures.
- Switching to LED lighting allows for reduced illuminance without compromising visibility.
- Unnecessary indoor lighting — particularly in empty office buildings at night — should be turned off. This will help prevent leakage of interior light into the night sky.
- The use of blue lights at night should be avoided:
- Outdoor lighting with strong blue content is likely to worsen sky glow because it has a significantly larger geographic reach than lighting consisting of less blue.
- Blue-rich white light sources are also known to increase glare and compromise human vision, especially in the aging eye. These lights create potential road safety problems for motorists and pedestrians alike. In natural settings, blue light at night has been shown to adversely affect wildlife behavior and reproduction. This is particularly true in cities, which are often stopover points for migratory species.
- DarkSky recommends that only warm-appearing light sources be used for outdoor lighting. This includes low-pressure sodium (LPS), high-pressure sodium (HPS), and low-CCT LEDs.
- “Warm” toned or filtered LEDs (CCT 3000 K or lower; S/P ratio 1.2 or lower) should be used to minimize blue emission.
Light pollution is harmful – Source: https://darksky.org/resources/what-is-light-pollution/light-pollution-solutions/
About the Objects
IC 1805 and IC 1848, also known as the Heart Nebula and Soul Nebula, are located in the constellation of Cassiopeia it is an Emission Nebula, that resembles a human heart, and the other nebula for some resembles a soul, I am not sure that I see that resemblance. The Soul Nebula lies very close to the Heart Nebula. In long exposure images, some of the gases from each object can be seen interacting! The two nebulae are often captured together with either a small telescope or a camera lens. They both share similar characteristics, such as color, gas composition, and size. It is estimated between 6,500 and 7,500 light-years away from Earth and was discovered on November 3rd, 1787 by William Herschel.
The nebula was given its name the Heart Nebula because of its intensely red glowing gas and dark dust lanes that form a shape that resembles a heart symbol. It forms a famous complex known as the Heart and Soul with its smaller neighbor Westerhout 5, also known as the Soul Nebula, which lies just 2.5 degrees to the southeast.
The Heart Nebula is around 150 arcminutes in size and has been given the designation of Sharpless 2-190 in the Sharpless Catalogue, as well as IC 1805. The brightest part of the Heart Nebula has the designation NGC 896 in the New General Catalogue. It is classified separately because it was the first part of IC 1805 to be discovered.
The glow of the nebula comes from the radiation of a small open cluster of stars known as Melotte 15. The cluster contains very young, blue, hot supergiant stars that are about 1.5 million years old and is located near the nebula’s center.
Melotte 15
Several of the bright stars in Melotte 15 have a mass almost 50 times that of the Sun, as well as many faint stars far less massive than the Sun. Melotte 15 once contained a microquasar, a radio-emitting X-ray binary system, but the system was expelled from the cluster millions of years ago.
The Heart Nebula is located in the vicinity of Maffei 1 (PGC 9892) and Maffei 2 (UGCA 39), which are the brightest galaxies in the IC 342/Maffei Group — the nearest galaxy group to our Local Group.
The Heart and Soul nebulae shine bright in red light due to the emission of that specific color of light by the excited nearby hydrogen gas and form a large star-forming complex in the Perseus Arm of the Milky Way. The region is barely visible in small telescopes.
The region of the sky that the Heart and Soul nebulae are in also contains several smaller nebulae, such as the Fishhead Nebula IC 1795. The region contains seven open clusters of young stars.
Observing Details
Right ascension 02h 44m 13s and Declination +60° 59′ 02″, with an apparent size of 150′ x 150′. It has a magnitude of 18.3, with an absolute magnitude of 6.5. With a radius of 165 light years. Other designations: Sh2-190 – The Running Dog nebula, Sh2-199, LBN 667 the Embryo nebula, and Westerhout 5.
Location in the Sky
Annotated Image
About the Imaging Location
Broemmelsiek Park was made possible by the commitment of Jack and Betty Broemmelsiek to preserve the natural beauty of St Charles County. The original land acquisition of Broemmelsiek Park took place in July 2002, which included a partial donation from the Jack Broemmelsiek family. Located about 6 miles South of Wentzville, Broemmelsiek Park is a St. Charles County Park with a dedicated astronomy site that is open 24/7.
The park is split into three main areas: A main park, an off-leash dog area, and an astronomy view area.
Every Friday night, weather permitting, the Astronomical Society of Easter Missouri (ASEM) members conduct an open house during which most of the telescopes there plus many portable telescopes are used for public viewing. It is a great family event.
The Bortle Scale Class sky for this area is about 5.
Equipment used
Scopes: RedCat 51, with the ASI2600.
Acquisition details
Frames 29×300″(2h 25′) (gain: 100.00) f/4.9 -10°C bin 1×1. Integration: 2h 25′ Darks 20, Flats 20, Flat darks 20. Avg. Moon age was 13.71 days, Avg. Moon phase Waxing Gibbous 99%, Moon Angle 0.55°, Moon distance 364,852.42 km, Bortle Dark-Sky Scale 8.5, Temperature 58°, Wind 3mph.
During a Waxing Gibbous the moon rises in the east in mid-afternoon and is high in the eastern sky at sunset. The word Gibbous first appeared in the 14th century and has its roots in the Latin word “gibbosus” meaning hump backed. The Waxing Gibbous on September 28 has an illumination of 99%. This is the percentage of the Moon illuminated by the Sun. The illumination is constantly changing and can vary up to 10% a day. On September 28 the Moon is 13.71 days old. This refers to how many days it has been since the last New Moon. It takes 29.53 days for the Moon to orbit the Earth and go through the lunar cycle of all 8 Moon phases.
Software Used
Pleiades Astrophoto PixInsight · Russell Croman Astrophotography BlurXTerminator · Russell Croman Astrophotography NoiseXTerminator · Russell Croman Astrophotography StarXTerminator.
The Final Images
Until the next adventure and thank you for stopping by!
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