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Posts posted by Bender

  1. I spent the last couples of days looking for 38mm (1.5”) eyepiece caps for my Tak LEs.

    surprising how hard it is to find something as basic as this . Does someone would have a pointer where to find a handful? 

  2. Thats a good start :)  i am happy with Cheshire/Catseye collimation, just wanted to confirm that i use the right mark on my primary to do so.

    Now i just have to work out what the difference between infocus and outfocus star image means. 

    I am visual observer only and generally happy with the views, but interesting to see if my OO mirrors live up to premium you pay.

  3. It has been a while since my last post, as i don’t seem to have the same spare time I used to have.

    I decided a while ago on a simple setup, a 10” OO dob with binoviewer for longer sessions and a 6” OO tube on a small photo tripod as grab and go scope. Both with their top spec mirrors.

    To help with collimation I got Catseye primary sticker for both, and in both cases found the existing primary spot (which I wasn’t able to remove – but I didn’t try to hard) to be a few millimetres of from the Catseye spots.

    It has bugged me since then if I placed the Catseye correctly. Yesterday I all the sudden had the epiphany that a simple star test should show if, when collimated with the Catseye spot, the scope is proper collimated or not.

    Infocus showed nice concentric circles when pointing the 6” at Polaris with a 6mm ortho, so I can assume that my Catseye sticker placement was correct after all?


    Seeing wasn’t perfect with a slightly unstable image and flaring showing but the circles showed clear enough.

    Now one thing I noticed was the stark difference between infocus and outfocus. I attached a rather bad drawing. In focus I saw a middle spot and 1-3 ? rings around (depending on focuser travel) all with the same brightness, and a outerring, which was considerably brighter.

    Out focus I only saw a bright ring and maybe, a realy dark middle spot and ring inside the bright one.

    I only started Suiters book on star testing, but it sounds both infocus and outfocus should look similar?


  4. After receiving my new dob I went out to order the cats eye kit and then took the ota apart to instal the cats eye dot on the primary.

    While I was on it I thought I might as well flock the upper and lower part of the tube.

    I then started the collimating process, making sure the 4 spider vanes are equally long (tick), the focuser is perpendicular to focal axis (holding a ruler in front of the Cheshire and on the opposite side of the tube, tick).

    Then I inserted the secondary screw on its own and checked if the cross in the Cheshire lines up with the screw to see if the focuser points towards the primary axis.

    Unfortunately it just touched the outside of the screw..

    Turning the Cheshire, the focuser and finally the focuser base by 180 degrees didn't change anything so it seems ota is slightly oblated?

    2 washer on one side between focuser base and ota brought the Cheshire in the focuser in line with the screw from the secondary.

    I can't find much that other people had similar problems, might there be anything I am missing ?



  5. Still debating the best way on how to improve on my 100ed / Quark combo. I got a TV 40mm plossl to get the magnification down and would like to go a bit lower. As a reducer in front of the plossl wouldn't help with the small fov I rather try to use a reducer in front of the quark.

    I saw a picture from Stu, he had the Orion 2" 0.8x in front of the quark.

     the 0.8x would get me down to an fl of 7.2, still within the recommended range.

    Looking for recommendations for a reducer with filter thread to fit my 2" UV/IR cut filter in front. Idealy with a 2" nose piece and a T2 thread on the other side to fit a 2" ep holder. Don't wnt to spend more then I have to, but on the other hand after investing in the whole set up, dont want to save at the wrong end either.

    The Baader 2" deluxe ep holder has a light path of 53mm, close to the 55mm back focus recommended. Not sure though where exactly the focal plane of the Quark is.

    The versions from Orion, Altair Astro and Long Perm look all similar, but show a wide range of price




    Then for twice as much is the TV reducer



  6. Thanks, I had a look and found for the Antares 0.7 2" reducer measurements how the magnification will work out. The reducer needs 78mm and I think I have 90 between the fr and the shiny bit inside the quark nose piece. This would give me 0.75x reduction, perfect :)

    The only problem is that the Antares fr doesn't seem to have a filter thread for the uv ir cut filter.

    How does the fr affect the in/ out travel need ? Do I have to rack out further with the fr in place.

    (The orange card board is an attempt to deal with the excessive er of the 40mm TV plossl ;) )


  7. I used my 100ed a few times with a Quark and quite enjoyed the views. This morning the views with my TV40mm plossl were amazing.

    I'm tried to get my head around the use of focal reducer but I am still confused.

    If I would like to turn my f9 scope into a let's say f7.5 with not only the lower magnification but also wider views a 40mm plossl would give in a generic f7.5 refractor, how would I go about it. Focal reducer in front of the quark or eyepiece, or doesn't it matter.

    I also read a fr will increase the bandwidth of the quark.

    Lastly, I used the quark a few times and only noticed today that on side of the fob was darker then the rest. Is this what people called banding ?

  8. I am looking for recommendations for a 100 - 120mm scope that I will primarily use with my Quark ha ep.

    I had a 80ed which gave nice views but wasn't bright enough so I tried a 80/480 scope which again was good but lacked something.

    Finally I tried the quark in my 100ed and was quite please but the magnification is borderline.

    As I like the 100ed as a light weight grab and go I was now thinking of maybe adding another faster scope that will be mostly used with the quark.

    Some people like the startravel 102 f5, other found it not as good as a ed scope, even with a narrowband quark.

    TS stocks Bresser 102/600 achros which are closer to the recommended fl range.

    Which scopes worked for you that don't cost an arm and a leg.

  9. Hope it is ok to join in with a question. Since the Baader steel track are not available anymore, has anyone experience with the TS acu clone (looks the same as my OO UK aco focuser on my vx10) I would like to upgrade the focuser on my 100ed and its either the new baader clones or a moonlite.

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