September 1st, 2022, 1:15 a.m. local time
Ever wonder what planetary imaging is possible through a Dobsonian telescope? Today's image of Jupiter may be my best example to date.
Dobsonian telescopes are not for astrophotography. They are intended for naked eye observation, and are quite good at it. You can easily move the tube in all directions without fiddling with nobs and levers. Just push in the direction you want to aim.
A Dobsonian's inherent advantages for simple observation make it ill-suited for most photographic imaging of the sky, particularly deep sky objects (stars, clusters, nebulae, galaxies). However, with a lot of practice, you can squeak out decent planetary images, for the bright planets.
Early on the morning of September 1st, I shot the videos which made up the final image of Jupiter you see above. It is incredibly in-focus, and likely the best I can do with my entry-level DSLR camera.
This is also the first time I set the ISO down to 200. Jupiter is still approaching opposition, and is very bright. I may try ISO 100 next time, to see if I can further reduce noise in the final image.
How did I get the focus so good? The trick with Jupiter especially is to set the ISO to about 3200, 1600 if you can handle it. Then, start focusing until you see the faintest of the Galilean moons appear on the LCD screen. In other words, ignore Jupiter when focusing, concentrate on its moons.
If only the Great Red Spot was in view for this photo, I may have made it my iPhone's wallpaper.
Summary of my equipment, settings, and software used:
- Telescope: Dobsonian reflector 254mm / 10″ (homemade)
- Camera: Canon EOS Rebel SL3
- Barlow: TeleVue Powermate x5 1.25″
- Filter: Baader Neodymium 1.25″
- Canon T ring and adapter
- Relevant camera settings:
- ISO 200
- Exposure: 30
- HD video at 60fps
- Created from three videos of about 25s each, best 35% of frames (via Autostakkert)
- Software for post-processing:
- Registax 6
- PaintShop Pro for minor touch-ups