Old 15-11-2020, 09:10 AM
hypersonics (Deepak)
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Smile Observing Jupiter

Hi All,

After many months of inactivity, I used my 10" Dob yesterday to observe Jupiter. I was able to use 30mm and 15 mm eyepieces, however, in both the view was not crisp and clear despite focusing the eyepieces. This is the first time I have observed a planet though and not sure what to expect. Is this something normal? Or, time to collimate the telescope?

I was able to see some faded brown stripes across the planet (used star walk app to confirm that it was Jupiter that I was aiming at.)

Secondly, in both 30 mm and 15 mm eyepieces I saw some three lights aligned with Jupiter. I'm wondering are these moons of Jupiter or, an optical artifact of the eyepiece/telescope?
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Old 15-11-2020, 09:24 AM
alval (Alan)
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The crisp and clear bit could be to do with the atmospheric conditions of the night, with those eye pieces you wouldnt have had a lot of magnifcation. That was Jupiter and the three bright dots were the moons, but there is generally four visable unless one is passing behind or in front of Jupiter itself.
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Old 15-11-2020, 10:03 AM
hypersonics (Deepak)
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Glad to know they were moons.

Your are correct, initially I was able to see 4 spots, almost perfectly aligned. However, later when I swirled over to 15 mm, I could only see three of them.

Another problem that I face is the alignment between finder scope and eyepiece. They never match. How to fix this?
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Old 15-11-2020, 02:32 PM
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Max Vondel (Peter)
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To fix the alignment of your finderscope, first collimate your telescope
Then pick a distant daytime object such as a pole or tree. Use your lowest power EP and adjust the screws on your finderscope bracket till you zoom in on your target. You can then use your higher power EP to fine tune things.
You can do this at night of course but daytime is much easier
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dobdonian, eyepiece, jupiter

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