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All a bit out of focus...


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This was my first ever attempt at looking at a planet (actually looking at anything) through my telescope (Celestron 127 SLT). With the 26mm eyepiece Jupiter seemed OK but with the 9mm it was quite out of focus (this was the best I could get it) and moving the focuser in either direction from this position made it even worse.

I'm assuming I'm doing something wrong - can anyone give me any pointers? I know it is a rubbish picture but just seeing Jupiter's moons near the planet through the eyepiece was unbelievable.




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It might just be bad seeing - non-ideal atmospherics etc?

The first night I observed Jupiter I had similar problems. Turned out to be very slightly dodgy collimation and just poor seeing. A tweak to the collimation and a better night made all the difference.

That’s just my personal experience, I’m no expert and others on here my have other/better suggestions!

good luck!

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Jupiter is quite low in the evening so it might be a case of bad seeing or heat plume from a nearby house.

The best way to test the optics is to pick a bright star near the zenith when the stars are shining steadily (without any twinkling) and use your 9mm eyepiece. You should see the Airy disc like this one:


( well looking much smaller than this). If you see anything else then could indicate a problem with the scope or the eyepiece.

Edited by Nik271
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Jupiter is quite low and any planet is going to be affected by the jetstream in viewing/ imaging

Using a smaller eyepiece will need better viewing conditions 

And if you think collimation could be a problem have a look at this



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Nice start! You can use an app called the Moons of Jupiter to identify them. I would try and reduce the exposure on your iPhone - with an 127 Mak, you will definitely see the main cloud bands. You can then fine focus. Using a peg on the focuser knob will give you better fine control. 

When you get good focus, keep the planet centred and record a video (maximum of 3 minutes). You can then stack and process the image.

I started with my smartphone, then used a DSLR and am presently using a Zwo planetary camera. In retrospect, I should have left out the DSLR phase and gone directly to the planetary camera.



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