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Skywatcher 5.1 parabolic reflector for DSO?

  1. Sep 2, 2004 #1
    Skywatcher 5.1" parabolic reflector for DSO?


    I've been scanning the night skies with my trusted 12 X 50 binoculars up until now and want to move onto a reflector for deep-space objects.

    Budget and portability have pointed me towards the below scope and i wondered whether any other members have any experience with this model or given the specification can comment on its suitability. Unfortunately, i don't have the best of viewing conditions (city light pollution!), but with my binoculars i've been able to make out M13, M31, M34, M92, and others.

    Skywatcher Explorer 130P
    5.1" Parabolic Newtonian Reflector
    f/650 (f/5)
    Magnification: x26 & x65
    Eyepieces (1.25"): 10mm & 25mm

    Full spec here:


    Thanks in advance for all your help.
  2. jcsd
  3. Sep 2, 2004 #2


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    I don't know how much this scope costs, but I personally would not buy it.

    You don't need an equatorial mount unless you plan on doing photography, and even then this mount is flimsy and and has no clock drive. Even if you add the optional single-axis drive to it, I'm rather sure its performance will be poor. The mount also lacks any sort of polarscope or other device for accurate polar alignment, so even if you overcome the drive issues, you will have to drift-align it every time, which will, in a word, suck.

    The telescope looks rather cheap. Some of the most important specifications are missing: the accuracy of the mirror figure (1/4 wave, 1/10 wave, etc.), the coating types, and so on. This leads me to expect that the optics are not particularly good on this telescope. The eyepiece design is also unspecified, leading me to suspect the supplied eyepieces are not very good either.

    The red dot finder is practically useless, because the dot will obscure whatever target you put it on. You would do better with a Telrad or Rigel QuickPoint finder, which use rings instead of a dot.

    I would recommend that you purchase a Dobsonian-mounted telescope like the Orion XT8 8" reflector. It also comes with Plossl (good) eyepieces, a 2" focuser, a real finderscope (which you should supplement with a Telrad or QuickPoint), and can be easily upgraded with computerized pointing. The Orion telescopes are widely known for their generally excellent optics.

    - Warren
  4. Sep 2, 2004 #3


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    Warren is right on all counts. You are far better off buying the best optics you can afford on a stable mount. For the budget category you are in, an 8" dobsonian is the obvious choice. The mount and tripod shown in that picture are way too flimsy to be useful, and unless the mount is properly polar-aligned, you'll tweaking those RA and declination knobs all night long. It's a whole lot easier and more intuitive to nudge a dobsonian as an object drifts in the field, and you can slew to a new object quickly without having to de-clutch the mount. Also, it is very difficult to accurately figure short focal-length mirrors, and at this price-point, I'd be willing to bet that the optics are very poorly corrected.

    Orion is a decent company, and their optics are about the best you can expect in their price range. Give them a try. Maybe you will want to go down a step to a 6" dobsonian and use the difference in price to buy a set of Tirion charts and/or a Tel-Rad finder. You'll be glad you did. A large-format bound Tirion Sky Atlas 2000.0 will help you learn the sky, point you to interesting objects, and allow you to plan your observing sessions.

    Planning observing sessions can be a fun activity on nights when you're clouded in. If you observe from a location where your horizon is blocked by buildings, mountains, etc, learn to predict which areas of the sky will be in your "window" the next clear night and make a list of the objects you want to see. You may want to make several lists, like double stars (color contrast/hard to split), galaxies (bright/diffuse) planets, quasars (yep, some are visible in a 6") and so forth, so if the clarity and/or steadiness of seeing isn't ideal for one type of object, you can move to another type of object very quickly.

    Keep these plans in ledger books, and leave enough room on the pages so that during your observing you can make entries, like drawing tiny asterisms that you found by accident, or writing how the dust lanes in a galaxy were observable through your scope, although you hadn't noted them before. You should always record the oculars used, and always note the weather/seeing conditions for each session. Don't worry about whether your assessments are accurate to any particular standards - you're keeping these records for YOU, and they will be valuable references next year and the year after that.

    Do this, and you will become an astute observational astronomer very quickly. You will learn the night sky, you will understand and predict the effects of seeing and weather in your viewing area, and you will push the limits of your abilities and your equipment. Please don't regard ledgers and record-keeping as drudgery. This is a FUN hobby, and the records will help you grow. They will also give you interesting avenues to explore and goals to exceed in the coming years.
  5. Sep 3, 2004 #4
    Thanks guys for taking the time out to reply in such detail. Very helpful indeed!

    Here's a review of this scope (obviously it's going to be a pretty positive review as it's linked from the manufacturers own site!):

  6. Sep 19, 2004 #5
    OF course it depends where u live (dark skies, city, etc) but.....bigger is better ;)......go with the 8".......no one can resist aperture fever.....Dobs are OK but i hate telescopes w/o setting circles......if you want to do some quick observing i like just lining everything up........plus if ur tall Dobs like to hurt ur back lol.
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