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  1. #1
    FiremanE42000's Avatar
    FiremanE42000 Guest

    Default Orion StarMax 102mm EQ or AstroView 120mm EQ?

    I'm looking to purchase my first scope and I'm between the Orion StarMaxT
    102mm EQ Compact "Mak" and the Orion AstroViewT 120mm EQ Refractor. Has
    anyone used either one or can anyone give me an idea as to which one might
    be best? Thanks

  2. #2
    David Nakamoto's Avatar
    David Nakamoto Guest

    Default Orion StarMax 102mm EQ or AstroView 120mm EQ?

    The refractor has color dispersion (usually seen as blue or violet fringes on
    everything that's bright enough to show it), perhaps less contrast, and the
    longer tube may be a problem in the wind. The Mak will offer dimmer views due
    to some of the light being obstructed by the secondary mirror.

    Is there a reason you won't go to the Orion 127mm Mak? I and a few friends have
    used this scope. One, who is very experienced, claimed deep sky objects looked
    better than in his 8-inch SCT; better contrast even though a bit dimmer. I can
    attest to it's great views of the moon and planets where I've used it the most.
    If you can afford it this is the scope I'd recommend.

    Good Luck !

    --- David
    Pinprick holes in a colorless sky
    Let inspired figures of light pass by
    The Mighty Light of ten thousand suns
    Challenges infinity, and is soon gone

    "FiremanE42000" <> wrote in message

  3. #3
    Stephen Paul's Avatar
    Stephen Paul Guest

    Default Orion StarMax 102mm EQ or AstroView 120mm EQ?

    "FiremanE42000" <> wrote in message

    These scopes are pretty much in different categories as far as use is

    The 102mm F13 Mak is a small instrument with a long focal length (around

    The 120mm F8.3 refractor is a larger instrument with a shorter focal length
    (around 990mm).

    One way to look at it is that the Mak is basically a replacement for a 102mm
    F13 achromat refractor (although it isn't quite that simple, and the 102mm
    F13 achromat will certainly outperform the 102mm Mak for lots of reasons, as
    discussed below).

    With that in mind, the question you might really need answered is, which is
    better, a 120mm F8 refractor, or a 102mm F13 refractor?

    The answer would be that the 120mm F8 will be better on deep sky objects
    like nebula, open clusters, globular clusters and galaxies, where low powers
    are most useful. However, due to the relatively short focal length in its
    refractive elements (primary lens), it will have quite a bit of "error" in
    bringing all colors to focus at the same point at high power. It will
    therefore be a somewhat poor performer on planets, which demand high power
    to bring out details at larger image scales.

    A 102mm F13 refractor will be good on planets, but lacks the light grasp
    (apeprture) to make deep sky images appear as bright as they will in the

    This would also hold true for the 102mm Mak, if it performed as well, which
    it will likely not. The rule of thumb for a Mak is it should have equivilant
    performance to a well color corrected refractor equal in size to the
    aperture of the Mak, minus the "central obstruction" of the Mak's secondary
    mirror (the dot on the front lens). This obstruction might be as large as
    30% by diameter (30mm), reducing the performance to that of a well color
    corrected 70mm refractor.

    Bottom line? If you are dead set on one of these two scopes, for whatever
    your motivation (it's not price alone is it?), then the 120mm would be
    "better" for deep sky, and the 102mm would be better for planets, and double
    stars (and portability).

    For the price of the Mak, you could possibly get a scope that is more
    capable in raw optical performance. Like a 6" Dobsonian. The 6" F8 Dobsonian
    is virtually without color error, has a lot more light grasp, and is quite
    easy to manage. The only real negative of the Dobsonian, is the lack of a
    clock drive, which means you need to nudge it along to keep an object in the
    eyepiece. It's kind of a pain, but you will see better what you are looking
    at, for the same money.

    Given that low power views are most often what are used for deep sky (half
    degree to 1 degree field of view), you get lots of time between "nudges", so
    it is only when planet observing (1/4th degree field of view is not
    uncommon) that the Dobsonian is at it's worst.

    Good luck,

  4. #4's Avatar Guest

    Default Orion StarMax 102mm EQ or AstroView 120mm EQ?

    On Mon, 28 Mar 2005 14:52:57 -0500, "Stephen Paul"
    <> wrote:

    Nicely said...

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  5. #5
    Doink's Avatar
    Doink Guest

    Default Orion StarMax 102mm EQ or AstroView 120mm EQ?

    Reconsider the 120ST f/5. Forget the MAK. You can get one of those toys
    later. Maks are a pain in the butt if you're new----try collimating one!
    Dew is a huge problem. Winter---cool down is a problem and by the time it's
    cooled enough to stop the boiling views the dew has formed. F/12, DIM.
    Field of view is small, harder to find things.

    And yes, if you're 4 feet tall a 6" DOB is a great starter scope! And if
    you're 25 years old and work out every day, get a 10" DOB. Lots of fun to
    set up and your wife will love having it in the guest room---until you sell
    it because you never use it. You'll need two other accessories: A Telrad
    to find things and a chiropractor because your back will be killing you the
    next day.

    Get the 120ST---then go to Universal Astronomics and get a GREAT Alt/Az
    mount----don't get the POS that Orion sells. It's useless. Orion sells 2
    good mounts: SkyView Pro and the Atlas. The rest are JUNK. Look at the
    Unistar Deluxe from Universal Astronomics. Yes, not cheap....and you'll
    love it and use it every day. And you'll observe----more than 80% of what
    this group does. They read S&T and have have long debates about refractors
    vs. SCTs....sillyness. And they spend hours screwing around with Photoshop
    to create phoney images that you can get any time on-line...


    <> wrote in message

  6. #6
    Doink's Avatar
    Doink Guest

    Default Orion StarMax 102mm EQ or AstroView 120mm EQ?

    One other piece of advice----get as far from this user group as possible.
    Talk to someone in person---find a club and go to a meeting. The mess in
    this group will only confuse you----they couldn't agree on adding water to
    put out a fire. Of course, they can debate the molecular structure of the
    water, the properties of the fire, how the water should be
    applied----they'll even debate the term "fire"----but grab the hose and put
    it out? Not this group----


    <> wrote in message



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