Solar Imaging:
From £20 DIY Hacks to Mega-Nerd H-Alpha Setups

I’ve been on a four-year quest to find the most cost-effective ways to image the Sun Although many of my experiments failed, after testing countless unusual filters and setups, I can now confidently point you toward the best solar gear on the market today. (BTW the giant solar print is available to buy here)

⚠️ SAFETY FIRST: Read This Before You Look Up
Solar astronomy is amazing, but it’s the only hobby where the subject of your photo is a literal nuclear furnace trying to destroy your gear and your retinas. Please follow ALL safety instructions provided by manufacturers.

The Best Budget Solar Filter: Baader AstroSolar Film

Baader AstroSolar Safety Film costs around £25 for an A4-sized sheet (20x29cm). It is incredibly versatile; you can cut it out and make a DIY mount using cardboard and sticky tape, or 3D-print a cell to fit any optical device you own—be it a telescope, binoculars, or even a camera lens.

This view reveals the temperature of the Sun’s surface (the photosphere). The cooler regions, like sunspots or the edges of convection cells (granulation), appear darker, while the hot regions, like faculae (the web-like network seen around sunspot groups, especially near the Sun’s limb), appear much brighter.
Note: While you might occasionally catch a massive solar flare with this filter, it must be exceptionally strong to be visible on the Sun’s surface. I only know one living person—the master mirror-maker Terry Pearce—who has actually witnessed a white-light flare through this type of filter!

Specialist Filters for Solar Photography

Filter Type	What you are seeing	Key Features	Difficulty
White Light (Baader ND 5.0)	The Photosphere (The “Surface”)	Sunspots, Granulation (convection cells), Faculae (bright patches).	Easy: Great for beginners.
Solar Continuum (540nm Green)	High-contrast Photosphere	Sharper Sunspots and Granulation; eliminates telescope color blur.	Medium: Needs ND 3.8 film or similar & UV/IR cut filters.
G-Band (430nm Blue)	The Magnetic Network	Deep contrast on the “Bright Points” where magnetic fields are strongest.	Medium: Needs ND 3.8 film or similar & UV/IR cut filters.
Calcium-K (393nm UV)	The Lower Chromosphere	Solar “Plage” (bright clouds), Super-granulation, and massive flares.	Medium/hard: Needs ND 3.8 film or similar and for detailed views a non achromatic telescope and good seeing.
Hydrogen-Alpha (656nm Red)	The Chromosphere (The “Atmosphere”)	Incredible, prominences, Filaments (magnetic rivers), Spicules, and violent Solar Flares.	Medium/Hard: Requires an Etalon (Quark/Phoenix) and potentially an energy rejection filter and it is expensive.

For those who want to go to the next level with a camera rather than an eyeball, Baader AstroSolar Photographic Film (ND 3.8) which blocks less light can (in fact must) be used with specialist filters.

DANGER: This film is for photography only NOT FOR VISUAL. Even with a camera this film could still damage your camera if it’s not used in conjunction with specialist narrowband filters which bring the Sun’s brightness down to safe levels for a sensor.

Pro Tip: Always use a UV/IR blocking filter in conjunction with the filters below to reduce the amount of invisible infrared radiation hitting your camera.

Mega Nerd Note: I actually use a modified Newtonian reflector for Calcium imaging. Reflecting telescopes don’t suffer from the spherochromatism (a specific type of optical aberration) that affects achromatic refractors at UV wavelengths. However, using a reflector on the Sun is for MEGA NERDS ONLY as even after modifying the mirror there are still massive heat risks).

Extreme Narrow Band Hα Filters

Imaging the Sun through Extreme Hydrogen Alpha (Hα) Narrowband filters is truly amazing. This allows you to see the hydrogen plasma thousands of miles above the surface, revealing magnetic “rivers,” solar flares, prominences, and filaments.

When I say narrowband, I mean really narrow. These specialist filters have a bandwidth of 0.1 to 0.05 Angstroms (0.01 to 0.005 nm).

• The Best Budget Entry: The Acuter Phoenix Elite 40. It provides a fantastic entry point into the world of solar observation, though its smaller aperture means you’ll eventually hit a limit on extreme fine detail.
• High-Resolution Setup: I recommend an f8 ish refractor (100mm+ aperture, and it doesn’t have to be a fancy one) paired with a DayStar Quark. These are Etalon filters that use internal heaters to precisely tune into the H-alpha line. Go for the “Chromosphere” version as you’ll see prominences with it anyway.

Mega Nerd Note: The bigger your refractor, the more you need to worry about heat entering the tube and creating a “heat haze” that ruins your images. You should always have a 2-inch UV/IR blocking filter (like the Baader Fringe Killer or Astronomik L-3) as high up the optical train as possible to reflect the heat back out or you can splash out on an Energy Rejection Filter.

Energy Rejection Filters (ERF)

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Most people buy the standard Quark, which has a built-in 4.2x Barlow. It’s designed to turn a standard f/7 refractor into an f/30 system—the “slow” focal ratio required for the Etalon to work.
But I use the Quark Combo paired with the Baader Research Grade 3x Telecentric Unit (TZ-3). My old f8 Sky-Watcher refractor becomes an f/24 system with this setup. Unlike an ordinary Barlow, this expensive telecentric lens makes the light passing through the Etalon almost perfectly parallel over a large field of view. This creates a uniform, high-contrast image across the whole sensor which is what I need to produce high resolution prints. I wouldn’t need this level of detail if I was only posting on the internet.

The “Mega Nerd” Setup: DayStar Quark Combo + Telecentric Lens

Most people buy the standard Quark, which has a built-in 4.2x Barlow. It’s designed to turn a standard f/7 (ish) refractor into an f/30 (ish) system—the “slow” focal ratio required for the Etalon to work. But I use the Quark Combo paired with the Baader Research Grade 3x Telecentric Unit (TZ-3).

Double Stacking

I double stack my quark with an etalon filter that I pulled out of an old PST. Double stacking greatly improves the performance because etalon filters aren’t perfect and they let some non Ha light through but when paired their imperfections are cancelled out. Explaining how to modify a PST is beyond the scope of this article. You’ll have to do some googling!

Warning: This setup is for Mega Nerds only. It’s expensive and requires precise back-focus spacing. But when you see the “spicules” and “fibrils” on the Sun’s limb with this level of clarity, you’ll know why I went to the trouble.