Narrowband North America
Narrowband shot of NGC 7000, the North America Nebula using a stock DSLR and William Optics RedCat 51 II telescope
Cygnus is one of my favorite constellations in the sky. It’s large, easy to locate and has several deep space objects to image!
Some areas in Cygnus are characterized by their high concentrations of ionized hydrogen atoms. Ultra violet radiation from nearby stars excites the HII gases and produces a brilliant, deep-red light at a wavelength around 656 nm.
These hydrogen-alpha emissions can be difficult to collect without a dedicated astro camera…or atleast they used to be!
With the help of a narrowband filter, even a one shot color camera or DSLR can capture Ha targets! For the picture above, I used a 2 inch ZWO duo band filter, inline with my telescope and camera. This allowed me to isolate the hydrogen-alpha wavelengths and prevent unwanted signals from reaching my camera’s sensor.
I had to take four minute sub exposures at ISO 800 for this to work. The integration time for me was about two hours total. Your mileage might vary depending on your shooting location, camera settings and sky conditions but even a single sub showed some of this Ha data when stretched in post-processing!
The North America nebula is just one of several HII regions in the constellation Cygnus. Some other great targets are the Veil Nebula and the Sadr region. I plan on tackling these myself when I get the chance!