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Thread: Skywatcher 102 vs 120 refractor

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    Default Skywatcher 102 vs 120 refractor



    Hi all

    While looking for my first scope I have had my mind set on buying a dobsonian 6” however after thinking about storage and portability I think I’ve decided not to get one. Now I have come down to two scopes the Startravel 102 and the 120. I understand that these refractors show CA but I won’t be using them for looking at planets but for looking at clusters/galaxies/Nebulae basically wide field stuff my skies don’t suffer from light pollution that much. I wanted to know is there a big difference in the two scopes as the price jumps up a lot if I go for the 120 version. Has anyone used these scopes? If you have would love to hear what you think of them. I’d Also like to know the cool down time for both and do I need to have a dew shield for them?

    Many thanks for the help

    Olli

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    Default Re: Skywatcher 102 vs 120 refractor

    I've not used either of those telescopes but there are a number of things which are clear:

    • The 120mm will collect quite a bit more light. That means you will see things with the 120mm which you would not see with the 102mm.
    • Chromatic aberration gets worse as you increase the aperture while keeping the focal ratio constant. Since both instruments have effectively the same focal ratio, the 102mm should be expected to have better optics.
    • Both appear to be under-mounted. IOW, their mounts are too wimpy for the size of the OTA. You can change the mounts but that will be an additional expense.
    • The focusers look a bit wimpy. Might be adequate, however.


    I'm sure one can enjoy either and I don't doubt I'd enjoy owning either of those scopes. But I bet I'd be looking for a different mount for either one of them.

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    Default Re: Skywatcher 102 vs 120 refractor

    Quote Originally Posted by OleCuss View Post
    I've not used either of those telescopes but there are a number of things which are clear:

    • The 120mm will collect quite a bit more light. That means you will see things with the 120mm which you would not see with the 102mm.
    • Chromatic aberration gets worse as you increase the aperture while keeping the focal ratio constant. Since both instruments have effectively the same focal ratio, the 102mm should be expected to have better optics.
    • Both appear to be under-mounted. IOW, their mounts are too wimpy for the size of the OTA. You can change the mounts but that will be an additional expense.
    • The focusers look a bit wimpy. Might be adequate, however.


    I'm sure one can enjoy either and I don't doubt I'd enjoy owning either of those scopes. But I bet I'd be looking for a different mount for either one of them.
    Hi thanks, I was looking at a bundle for around £335 on first light optics for a 102 on a az5 Mount. Would this mount be good enough for the 102? There was one much cheaper but on AZ3 and heard people have had problems with that.

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    Default Re: Skywatcher 102 vs 120 refractor

    I have both of those scopes that I use on different mounts. The scopes are very similar, the 120 shows SLIGHTLY more, a little more detail, a little more light grasp, and a little more CA. It requires more from the mount. For your purposes, either will work well and I like both scopes. They both do very well on DSOs and both are OK on the planets (I use filters for CA on planets) with the 102 being slightly better there.

    The AZ5 should hold the 102 very well.

    I would opt for this one over the bundle you are looking at. The mount is quite good.

    https://www.firstlightoptics.com/sta...120-eq3-2.html
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    Default Re: Skywatcher 102 vs 120 refractor

    the EQ3-2 that Ozman has mentioned is basically the same as the CG4 from celestron and i have the CG4 great mid range mount, i had the celestron version of the 120 but that is an F9 scope and its was excellent, sharp optics bit of chromatic on the moon but nothing silly, i have also the 102 version in an F9 and thats a brill scope as well that now rides the CG4, im looking at the 102 F5 that your looking at as i have its smaller brother the star travel 80mm and that is also i nice little scope that belies its price, that rides on my SLT / GT goto mount nicely , much better than the 102 ever did
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