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orley

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Posts posted by orley


  1. Love mine, had it a good number of years now. Great on planets and moon. Takes magnification up to 180-200x fine, although I tend to stay below 160x under my light polluted, unsteady skies. As your acquaintance infers, struggles somewhat on dso's, but then 4" is 4" - dark skies help. Doesn't weigh much so sits beautifully on EQ5/AZ4 mounts and upwards. Focuser is servicable but needs tweaking now and then.

    Sharp, contrasty views? Yes. Great detail on dso's? No - they are there, but just. 

    Over the years I've had a 150mm F5 newtonian, a 200mm F6 newtonian, a 150mm achromat and a 127mm mak. The 100ED is the only one I've kept. It is what it is, but what it does it does very, very well.

    My purely subjective view, of course!

    Tom

    • Like 2
    • Thanks 1

  2. 4 hours ago, jetstream said:

    "This is an amazing telescope. It takes high magnification like nothing else I’ve used and has provided the sharpest, most detailed lunar and planetary views of any scope I’ve owned. It really is “refractor like” and completely outclassed my Takahashi FS128 (itself a superb instrument) and in many ways equals my more recent 7 inch TMB APO. "

     

    http://scopeviews.co.uk/OrionOptics200Dob.htm

    One of many articles about newts with good optics and optimized central obstructions....  and many SCT's give excellent performance as well. My own 10",15" dobs "completely outclass" my SW120ED giving equal sharpness with much more detail.

     

     

    In fairness, the author of the linked article repeatedly points out that those exceptional views occured in rare, fleeting moments of (almost) perfect seeing. The key words here are 'rare' and 'fleeting', which probably is a good summation of seeing in the UK, and rather demonstrative of average conditions.

    Everything is subjective, of course. That's part of what makes life fun!

    Tom

     


  3. Light pollution prevents much deep sky observing from my location, so planets and brighter Messier objects are my thing.

    I have a 100ED and recently, after a year of gathering side by side observing experience, moved a Skyliner 200 dob on to a better home. The reason? To me, the refractor gives consistently better views of the planets.

    I'll go one further. My 100ED gives consistently better views than my 6" achromat too.

    Tom

    • Like 2

  4. 7 hours ago, Cosmic Geoff said:

    On the computer-assisted front, why not equip GoTo mounts with a third control axis? I understand this is the system used in the latest giant telescopes, where it is more practical to have an alt-azimuth mount with camera rotation than an equatorial without.  In combination with plate-solving, one could perhaps have an alt-azimuth GoTo suitable for astro-photography, which can be erected, turned on and left to sort out its own alignment, eliminating at a stroke polarscopes, Polarmasters and all the lengthy faff of polar alignment.

    This does already exist, to a degree. Look up the Track The Stars Panther mount - an alt az mount with goto that is suitable for imaging. The third axis is implemented using a mechanism to rotate the tube.

    Tom


  5. 4 minutes ago, ollypenrice said:

    It's hard to see why the extra weight would induce drift in the system over time, though I take your word for it that it does. It couldn't be something as simple as the tripod sinking into the ground or the legs slipping a little? Or the clutches not gripping perfectly?

    I like GoTo systems which can be painlessly 'updated' simply by going to a star near the target and re-synching. This can be more or less straightforward depending on the system. And, yes, GoTo should go to. That's why it's there!

    Olly

    Edit: Just anther thought. If your heavier rig has a longer focal length then GoTo will need to be better in accordance with the reduced field of view.

     

     

    Thanks Olly. I think it's that the weight is too much for the clutches. No matter how hard they are tightened there is slippage and I can't see any obvious way to fix this.

    Regards,

    Tom


  6. On 23 August 2016 at 20:12, ollypenrice said:

    The weight business is (to persue the fish theme :D)  largely a load of codswallop. It is really about  things like damping time (imagers can't wait for it but visual observers can) and tracking accuracy (imagers need it and observers don't.)  I think the best thing for anyone in doubt to ask is, 'Anyone out there using this scope on that mount to do this job?'

    Olly

    Absolutely. Indeed, I've found that the dampening times are acceptable when using the 6" refractor on the AVX. 

    I was simply making the point that I've found that the mount won't track reliably with this load - the goto's start off okay but worsen significantly as the evening goes on, no matter how carefully balanced the scope is and how accurately the mount is initially aligned. I don't experience this issue with a lighter load. Unless I'm doing something wrong, which is always a possibility :).

    We could argue that accurate goto's are not really essential, but they are one if the reasons why I bought the mount in the first place.

    Regards,

    Tom

    • Like 1

  7. As much as I love my AVX with my 100ED, it's just not coping with my 12kg 6" frac. As hard as I tighten the clutches it still slips and I lose goto alignment. A shame as up until now it's been a fantastic mount and I hate to post a negative comment.

    Do post and let us know how you get on.

    Regards,

    Tom.


  8. Hi all,

    Just to extend the original question a little...I recently picked up an old Meade AR6 achromat. It wasn't something I was particularly after, but opportunity arose and hey ho it's in my shed. I have an AVX mount which my ED100 sits on beautifully, but it struggles with the Meade - the dec clutch slips and I lose goto alignment pretty quickly.

    I've been pondering upgrading to an NEQ6, but have been put off by the size and weight. The Meade plus diagonal/rings etc. is coming in weight-wise at around 12kg. If I recall, the AZ EQ5 handles 15kg. Is this enough tolerance or should I be looking at the NEQ6. Of course with the AZ I've the added bonus of alt-az observing.

    What are people's thoughts?

    Cheers,

    Tom


  9. 9 hours ago, Beeko said:

    I've seen one of these in the flesh at Astrofest last year and they are beautifully made. The designer was very knowledgable.  I thought long and hard for a few months about buying one but feel it won't cope with imaging demands. This guy http://www.alphaquadrantobservatory.smugmug.com has been taking some amazing images with it though when I got in touch with him did say that the rotator option will only last 1-2 hrs. As I can't find anyone else imaging with the mount with equally impressive images, I feel it's too much of a risk. Beautiful mount though. 

    Hi,

    is 1-2 hours not enough? Can't you then just rewind the rotator and go again? Please forgive my ignorance :)

    I too saw it at Astrofest. It is a lovely, elegant mount, but, yes, pricey.

    Thanks,

    Tom


  10. 49 minutes ago, BobSki said:

    Drilling dents into the patio would probably result in my not being married and having to find new accommodation ?

    However, I have scratched three little arrows pointing to where the leg spikes go and she doesn't seem to have noticed those yet ?

    The holes don't have to be big or particularly deep, just enough to stop the tripod feet slipping out of them. Like Jimjam I find it a real time saver!

    • Like 1

  11. Hi all,

    Apologies for resurrecting this, but last night was the first chance I've had since to use the scope. This time I used a 20mm Meade 4000, a BST 12mm and a Pentax XF 8.5mm. The view was better - lovely on the moon - and the previous problem of the focusing either the inner or outer seemed to have stopped.

    However, now I seem to have the centre and top half of the field of view in focus, but the bottom third (or so) out of focus. This was especially noticeable on the moon. Is this down to collimation? I had the same problem with all eyepieces I tried.

    Thanks in advance!


    Tom.


  12. 1 hour ago, Daniel-K said:

    try backing the adapter out of the finder a bit see if that helps  

     

    18 minutes ago, BargeGazer said:

    I have the same set up and obtain a good focus just by sliding the camera in or out of the adapter, locking it in place then fine tuning with the finder scope focusser (start with the focusser in a mid point)  Try it in daylight and you can slide on the parafocal ring you got with the camera and then you will find it easier in the dark.

     

    David

    Yes, I had the same problem. This is the solution.

    • Like 1
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