My Recent Foray into Astrophotography

Astrophotography with an 8-inch Dobsonian

Astrophotography is hard.

You know what is even harder?

Astrophotography without a tracking mount—and I haven’t even gotten to the DSOs yet! Well…I have, but the images are not perfect. It’s a work in progress. I’m a work in progress.

I did get some good pictures of the planets, the Sun and the Moon though!

But first, let’s backtrack a bit.

I’ve had my 8-inch (203 mm) GSO Dobsonian telescope since I was an itsy-bitsy middle schooler. My initial views of the planets were not perfect. The Moon looked great through the telescope, but my chubby fingers got in the way of setting up the phone adapter correctly, and I couldn’t get any pictures. The one or two pictures I did get were blurry.

My 8" Dobsonian— all set up for some astrophotography...but first, I gotta listen to my favourite Yardbirds album!

8-inch GSO Dobsonian telescope with a clutch mount and tension knob
Credit: Tejraj

My telescope then faced a rather grim fate. I packed it up, and the best birthday present I ever received sat abandoned in one corner of my room, collecting dust instead of the light that it was meant to.

This year however, I started my undergraduate physics degree and I decided that it was high time I learned to operate a telescope. All that weight I had gained had to be shed too, and I figured, what better way than to haul a 13 kg tube and 12 kg mount up two flights of stairs?

And that is what I have been doing the past three months. I started hauling my telescope all the way to the terrace, with no idea about what I was doing. I went into it thinking I had to capture a single photographs or a few stills. I had no idea I was supposed to take exposures, and later on I struggled to figure out how to track the planet, stack the images and process the data without over-processing it to reveal hidden artefacts and details in the image. This post contains a bit of what I wish I knew when I first started—a lot of advice online is tailored to intermediates, and I want to offer a newbie’s perspective. I hope it is helpful.

I have two eyepieces—the GSO Super View 30mm eyepiece and the GSO Plossl 9mm. These arrived with the telescope. In the future, I definitely plan to expand my collection—I have my sights set on the Baader Hyperion Zoom eyepiece, which will provide a variety of magnifications to switch through.

The 30mm and 9mm eyepiece respectively
Credit: Tejraj

Also, a word of advice: the final stacked image is largely dependent on what astrophotographers call “seeing”. This refers to the overall atmospheric conditions, level of light pollution and the overall quality of the night sky. This will have a greater impact on your image than any skills and sophisticated equipment. In my opinion, a 6-inch telescope will give much better clarity and detailing in your data in a dark sky location than a 10-inch telescope in a more light-polluted area and unfavourable atmospheric conditions.

You might want to check the Bortle classification for your area on https://www.lightpollutionmap.info/ before you begin. What’s the Bortle classification system you ask? It’s a scale meant to classify skies according to how bright they are, and hence how suitable they are for dark sky astrophotography and stargazing. A Bortle rating of 1 is given to excellent dark sky sites, whereas a Bortle rating of 9 is given to light-polluted, urban skies.

The Bortle Scale on Stellarium
Credit: Stellarium

I live in a Bortle 9 area myself, so a high Bortle rating won’t kill your chances of imaging the planets— but it would adversely impact the quality of the data you’re seeking.

If you’re trying to image a planet, schedule your astrophotography sessions close to that planet’s opposition dates. These are the particular dates on which the planet is on the opposite side of the sky from the Sun, as viewed from the Earth. It's a good time to observe them because they are at their closest to Earth and in their full phase.

Try not to image through thick atmosphere, when the planets are close to the horizon—this exacerbates atmospheric distortion due to turbulence, and makes it more likely for you to be capturing your data right above heat sources like trees and buildings. Try imaging the planets when they are close to the zenith. I had to crane my neck really high to get my images, but it really is worth the trouble.

Whatever device you choose to use in order to capture your images—be it a regular cell phone camera or a DSLR—get the best phone/camera adapter you can get your hands on. You do not want your mom’s phone to slip off the adapter in the uncertain lighting and smash its screen your first day shooting. Not that I would know anything about that happening.

So, how do I shoot the planets, the Sun and the Moon?

When capturing planets, (or any celestial body, really) you want to take exposures, and not shots. This is to allow the detector on your cell phone camera or DSLR to receive enough light to reveal the finer details in the picture (Jupiter’s bands for example).

Once your finderscope is aligned with the eyepiece of your telescope, you can simply point the ‘scope at a planet and start observing through the eyepiece. Note that this alignment doesn’t have to perfect—it isn’t for me, and that works just fine. You can align the finderscope using some distant target (a tree or a building) or a star if it’s already dark.

So, you’ve got the finderscope and the eyepiece aligned and you can see Jupiter in all its glory. What next?

For planets, with a regular cell phone camera stuck to your eyepiece, you would want to lower the ISO to the 50-200 range, and adjust your shutter speed till it’s in the range 1/10 to 1/90. Zoom in until you can see the details.

For the Moon, an ISO of 300 works just fine for me. If the Moon looks good through the ‘scope, go ahead and capture it!

A low ISO works well for the Sun as well.

Caution: Never observe the Sun directly through a telescope, or even a finderscope! Even a split second glance could cost you your eyesight.

I use the SolarLite solar filter to capture the Sun. Note that the solar filter goes over the objective lens and not the eyepiece. You can fashion a simple solar filter for your finderscope as well, or use the trick that I use: view the Sun directly through the focusing tube without any eyepiece in it. Once you’ve got it, fix the telescope in place and insert the eyepiece assembly!

Ensure that the objective remains cool, or it may impact the quality of your data. The cooling fans at the bottom of my telescope help with this.

If you can see the sunspots, your image is in focus.

If you cannot see any details—on the planets, the Sun or even the Moon on an eyepiece—adjust the focuser and try again. It could also be due to atmospheric turbulence, so don’t beat yourself over it. Do not shoot if your image is overexposed/unfocused. Try to get as sharp a view as possible, and start filming. A 3 to 5-minute exposure should suffice.

Since you’re not tracking the body as it moves across the sky, it will eventually drift from your field of view. Gently nudge the telescope back into position, and you should be able to capture the celestial body drifting across for a steady few minute. Don’t worry about centering and tracking just yet. There’s software to help with that.

These are the three applications I use:

1. PIPP

A screenshot of my PIPP window

PIPP will automatically centre and track the planet or any body for you. Add your source file, check the ‘Planetary’ option if you’re viewing planets or ‘Solar/Lunar Close-up’ or ‘Solar/Lunar Full Disc’ depending on your capture. Process your frames and save them in the AVI/TIFF format—whichever you prefer. I save my files as AVI files.

2. AutoStakkert

Placing alignment points on Jupiter using AutoStakkert

Once you’ve got your AVI/TIFF file, you can go ahead and stack your frames on AutoStakkert. Open your file, analyse it and select the top 25 to 50 percent of your frames for stacking. You can use the auto generated alignment points or manually select the areas of high contrast or the features on the planet that you think stand out. Go ahead and stack your image!

3. RegiStax

Processing the image on RegiStax

After the first two steps, you have an image that is nearly done. All that is left is some minor touch-ups. Once you’ve got your image, open it on RegiStax. Adjust the Wavelet Layers 2, 3 and 4 to sharpen the image. This step requires some care, because over-processing can very easily lead to a funny-looking image. You do not want to amplify noise; only the specific features (belts and bands of Jupiter, the rings of Saturn) that you want to highlight. You can adjust the colour balance using ‘RGB balance’, and align colours using ‘RGB Align’.

If there’s a ghost ring in your image, the ‘Denoise/Deringing’ option might help.

And there you have it! Your very own image of Jupiter 715 million kilometres away or the Sun 150 million kilometres away—all from the comfort of planet Earth. Incredible, isn’t it?

Here are my images:

The Moon
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece
Magnification: 40x magnification
Camera Settings: ISO 200, 1/6s shutter speed
Phone adapter with standard cell phone camera
Single stills enhanced using RegiStax 6
January 2025

The Moon
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece with GSO ED 2" 2 x Barlow Lens
Magnification: 80x magnification
Camera Settings: ISO 298, 1/50s shutter speed
Phone adapter with standard cell phone camera
Single still enhanced using RegiStax 6
February 2025

An overexposed image of Jupiter showing the Galilean moons
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece
Magnification: 40x magnification
Camera Settings: ISO 1600, 1/7s shutter speed
Phone adapter with standard cell phone camera
Single still enhanced using RegiStax 6
December 2024

Jupiter
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece with GSO ED 2" 2 x Barlow Lens
Magnification: 80x magnification
Camera Settings: ISO 50, 1/10s shutter speed
Phone adapter with standard cell phone camera
8 to 10 shots, compiled using PIPP and stacked using AutoStakkert
Image enhancement using RegiStax 6
February 2025

Mars
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece with GSO ED 2" 2 x Barlow Lens
Magnification: 80x magnification
Camera Settings: ISO 50, 1/80s shutter speed
Phone adapter with standard cell phone camera
2-minute exposure, compiled using PIPP, stacked using AutoStakkert
Image enhancement using RegiStax 6
February 2025

A Sunspot
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece with GSO ED 2" 2 x Barlow Lens
Magnification: 80x magnification
Camera Settings: ISO 105, 1/100s shutter speed
Phone adapter with standard cell phone camera
Single still enhanced using RegiStax 6
February 2025

The Sun
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece with GSO ED 2" 2 x Barlow Lens
Magnification: 80x magnification
Camera Settings: ISO 174, 1/100s shutter speed
Phone adapter with standard cell phone camera
Single stills enhanced using RegiStax 6
February 2025

Saturn
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece
Magnification: 40x magnification
Camera Settings: ISO 200, 1/100s shutter speed
Phone adapter with standard cell phone camera
3-minute exposure, compiled using PIPP, stacked using AutoStakkert
Image enhancement using Registax 6
December 2024

The Orion Nebula
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece
Magnification: 40x magnification
Camera Settings: ISO 3000, 1/8s shutter speed
Phone adapter with standard cell phone camera
Single still enhanced using RegiStax 6
December 2024

The Pleiades
Gear used:
Telescope: 8-inch GSO Dobsonian telescope
8" (203mm) aperture, 1200mm focal length, f/5.9 focal ratio
Eyepiece assembly: GSO Super View 30mm eyepiece
Magnification: 40x magnification
Camera Settings: ISO 3200, 1/6s shutter speed
Phone adapter with standard cell phone camera
Single still enhanced using RegiStax 6
December 2024

I’m still learning, and that’s part of the joy of it. If you're trying astrophotography for the first time, I’d love to hear about your experience—drop a comment below!

The Nerd Cove