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Stargazing How useful are collimation eyepieces?

  1. Dec 17, 2012 #1
    How useful are collimation eyepieces? I wouldn't shell out the money for a laser collimator, but some of the eyepieces (like this one) are as cheap as $30, and appear to work very well.

    My scope came with a collimation cap, but even after trying to collimate my telescope, I'm still not sure if it's properly collimated.
     
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  3. Dec 17, 2012 #2

    Drakkith

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    Re: Planning to buy a first telescope?

    Welcome to my world. My Newt is...terrible. Flimsy design REALLY brings it down. My collimation on it falls apart just by slewing from one part of the sky to another. Couple that with the fact that I am TERRIBLE at collimation. I found the laser collimator to be the most useful for me, while the collimator eyepiece was decent also.
     
  4. Dec 17, 2012 #3

    russ_watters

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    Re: Planning to buy a first telescope?

    It would be better to learn star collimation, but it will be tough on a Dob since it requires high magnification. (and calm skies)
     
  5. Dec 17, 2012 #4

    Chronos

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  6. Dec 17, 2012 #5

    davenn

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    Re: Planning to buy a first telescope?

    thats great :)

    Its us "older guys" (like me) that learned how to get around the sky without digital setting circles and "goto" telescopes.
    LEARN and I say it again LEARN how to starhop you way around the sky to find objects
    yes it takes a little longer but the huge advantage is you will really get to know your way around the stars :)
    And that nite you are at some friends place and the only thing they have is a pair of binoculars, you wont be lost in showing them a few objects of interest

    Dave
     
  7. Dec 17, 2012 #6
    Re: Planning to buy a first telescope?

    Luckily, I'm almost forced to learn the skies, since I have a simple dobsonian mount.

    And I actually just got back from the meeting. It's very official, in that they are allotted a decent amount of money from grants, and are building a new observatory (there are on-going debates as to what type of telescope should go in it), but everyone there was very welcoming and relaxed. They were all at least 35 years or older, but this will only benefit me, because they all seem very experienced.

    Apparently, one guy got bored and built his own 32" dobsonian; I feel like I will have a lot to learn from them.
     
  8. Dec 17, 2012 #7

    Chronos

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    Re: Planning to buy a first telescope?

    My first scope had setting circles that proved utterly useless. Of course I had no clue how to polar align my scope [6" f8 newt], which was a contributing factor. The setting circles had like 5 degree increments which further exacerbated an already hopeless situation. My favorite eyepiece offered less than about 1 degree tfov, which was also unhelpful. Goto was a pipe dream back in those days, so, star hopping was the only option. I hated star hopping, and still do. Albeit, I admit, it was instructive.
     
  9. Dec 18, 2012 #8

    russ_watters

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    Re: Planning to buy a first telescope?

    While I have respect for the skill required to look for things without GOTO, IMO, this was largely a barrier that got in the way of the primary goal of looking at things. I'm not sorry to see that skill die.
     
  10. Dec 18, 2012 #9

    davenn

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    Re: Planning to buy a first telescope?

    in many ways you should be thankful that you have a "Dobo" mount, you really will never regret learning to move around the sky the old way.
    Goto scopes are great, only just got one myself at the beginning of the year after 40+ yrs in astronomy. But one has to be consious of not becoming too lazy and forgetting the basics by letting the scope find everything for them.
    There is nothing wrong with goto scopes, for some one who really likes to get around many objects quickly say... those that supernova hunt in a mass of galaxies regularly or if you are trying to find new faint objects, whatever they are... comets, asteroids, or deep sky objects then having the scope get you into the right area of the sky helps lots :)

    Dave
     
  11. Dec 19, 2012 #10

    Chronos

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    Re: Planning to buy a first telescope?

    You still need some basic star hopping skills, even with goto. I feel insecure until I can match the field of view to a star chart, but, goto is a huge time saver when it puts you close enough not to deal with the tediousness of leaping star to star from several degrees away to reach the target area. I've been a variable star observer for 40 years and finding those target fields are incredibly difficult compared to something distinctive, like a galaxy or planetary nebula. I still use my 40+ year old all sky charts.
     
  12. Dec 19, 2012 #11
    Re: Planning to buy a first telescope?

    Long story short, OwlAstronomy had to cancel my orders and fully reimbursed me for my purchases: the 20mm eyepiece ($33) and the variable polarizing filter ($20).

    So, I'm still stuck with my 25mm, standard-issued Plossl, the shorty 2x Barlow, and the extension tube that I bought (which has worked well thus far).

    So I've searched around a bit, and found this.

    So here are my options.... tell me if they're feasible or not:

    1.) I don't buy the case. I would consider making individual purchases based on what I need at any given time. That leaves me with the following magnifications:

    KEY: 2xB = 2x Barlow ... ET = Extension Tube

    25mm Plossl: 48x
    25mm Plossl + 2xB: 96x
    *25mm Plossl + 2xB + ET: 128x

    2.) [a.] I buy the case, selling what I don't need, keeping what I need.

    I would sell the 4mm and 6mm eyepieces (4mm gives too high of a magnification, 6mm would be redundant w/ 12.5 and Barlow) so that I could use them to finance a nice 5mm planetary eyepiece. I would compare the Zhumell Barlow with my Orion Shorty Barlow, and sell the lesser of the two. In this option, I would debate selling the 25mm Plossl or not; I primarily use it as a finder, and feel as if the 32mm would take over this role.

    That leaves me with the following magnifications:
    32mm Plossl: 37.5x (about as low as my telescope should go... or so the internet tells me)
    32mm Plossl + 2xB: 75x
    *32mm Plossl + 2xB + ET: 100x

    25mm Plossl [Refer to above for magnifications]

    12.5mm Plossl: 96x
    12.5mm Plossl + 2xB: 192x
    *12.5mm Plossl + 2xB + ET: 256x

    (And assuming I purchase a 5mm planetary eyepiece)

    5mm: 240x ... I wouldn't use the Barlow/ET for obvious reasons.

    [b.] I would be the scrooge of this Christmas, and follow suit as in Part A, but would skimp out on purchasing a 5mm planetary eyepiece (I am still in consideration of selling the 25mm Plossl that came with my telescope because there's an overlap in magnification when using 25mm with the Barlow and the 12.5mm by itself).

    I would do this because, when using EP + 2xB + ET with the 12.5mm, I can get up to 256x magnification, whereas with the 5mm eyepiece, I would be limited to 240x.
    _ _ _ _

    I know this seems ridiculous, but I am almost always incredibly careful when spending my own money. It also seems as if I should just altogether skip out on the case, since I would sell two of the four eyepieces, but the filters and Barlow would be very beneficial, and I haven't seen a package like this anywhere else.

    *Assuming I did my math correctly. The extension tube is 2" long, and the shorty barlow lense is 3" long. If I were to have a 3" ET, then my shorty barlow would bump up from a 2x to 3x, so I made my calculations under the assumption that, when using a 2" extension tube, it would essentially make a 2x Barlow into a 2.666...x Barlow lens.
     
    Last edited: Dec 19, 2012
  13. Dec 19, 2012 #12

    Chronos

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    Re: Planning to buy a first telescope?

    The 25mm plossl will be ok. It is unfortunate the OWL is unavailable, its a great EP for the money. You can still cruise ebay for a used wide field EP.
     
  14. Dec 19, 2012 #13
    Re: Planning to buy a first telescope?

    I found this eyepiece, along with these filters. I'll probably just buy these two separately and save myself the head-ache of trying to rely upon other people buying what I don't need.
     
  15. Dec 19, 2012 #14

    Chronos

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    Re: Planning to buy a first telescope?

    14mm is a bit short for a wide field. You really want something in the 20+ range.
     
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