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Ruud

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Posts posted by Ruud

  1. If you google for 'fungus on mirror' and you find that the images you get resemble what you see, then indeed, you probably got some fungus growing on your mirror.

    Keeping a mirror in a garage is probably a bad idea. Still, clean the mirror with a disinfecting agent (alcohol and propanol work - the two active ingredients of Baader's cleaning liquid). The spots may improve a bit and at least won't keep growing.

    After that, keep your mirror in a dry place and also avoid places that have a combination of (occasional) large temperature drops  combined with (occasional) high humidity. It's also a good idea to use a hair dryer to warm up your lens, corrector plate or mirror after bringing it in.

  2. Hi, welcome.

    What you saw was the shadow of the secondary mirror. That happens when you are way out of focus. You tried to use the focus knob as a zoom knob. It can't zoom though, only focus or blur.

    When you reach focus, blur is minimal and the planet will look as small as it gets through the telescope (same for stars: sharper is smaller). You'll see that Venus has a gibbous phase, slight more than half.

    ---

    The Moon was out. An easy way to test if you are focused properly is to have a look at the Moon: if that is sharp, the rest of the sky should be too. For practical purposes everything out there is at infinity.

     

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  3. For any given eye relief, with a larger apparent field of view you need a larger eye lens, and with a larger eye lens you get a bigger eyepiece.

    On top of that, large eye relief eyepieces often get longer with decreasing focal length. That is because they require a stronger first, negative group.

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    The Delites are petite, the Morpheus are lightweight and the Delos are heavy. You found the XW. There's also Nagler type 4. That's about it for the top shelf long eye relief choices.

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