Planetary imaging mistakes and how to avoid them!
Planetary imaging has been a popular sub-category of amateur astronomy for a long time. We listed some of the most common mistakes and how to avoid them to get better results!
1. Too little magnification
Planets are very small in apparent size. This is why we need a lot of magnification to have the subject large enough on our sensor to see potential detail at the surface. Most common mistake is to use too low magnification resulting in pixelated or blurry results as the image is undersampled. Cassegrain or Ritchey–Chrétien telescopes tend to work well as they have a long focal length natively. Newtonian scopes with a barlow lens work great too but whatever optical design you’re using the key is to have large enough magnification to fill atleast 1/6th of your sensor with the subject.
2. Focusing issues
When working on such high magnifications it is also recommended to use electronic focuser to avoid inducing unwanted vibrations to the image. This is especially true when using small sensors that most planetary cameras have as the field of view is really narrow and shaking the scope might throw you off the target completely.
3. Too long video clip
We want to shoot a video with as many frames per second as possible to capture the clearest moments the current seeing has to offer but depending on the planet you might also blur your image as the planet rotates missaligning the frames. Jupiter is a prime example of this and as a rule of thumb you should not record videos longer than 3 minutes at the most.
4. Bad collimation
Make sure your scope is well-collimated to get the sharpest image possible, even the most high-end telescope will produce a poor image if it’s out of aligment. Use proper collimation tools to check your collimation before each imaging session.
5. Uncooled OTA
To reduce air currents inside the optical tube you should leave your telescope outside to cool down atleast an hour before you plan to start imaging. These currents, or the lack of them, will make a huge difference in your final results.