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John

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Posts posted by John

  1. We spent a few (rainy) days staying with my brother and his family over Christmas and he introduced me to the joys of 3D printing. We managed to produce this 150mm long replica of the asteroid 433 Eros. We used public domain images to produce the necessary file for the 3D printer. Quite pleased with the result although it took 8 hours to print ! Just got to decide on a few other suitable subjects now (suggestions welcome ! :smiley:). 433 Eros was the object that the NEAR Shoemaker probe made the (very) close approach to back in 2000. The first image is from that probe. The others are of our replica. The real thing is 34km long by 11km wide.

     

    eros_near.jpg

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    onstand.jpeg

    painted.jpeg

    • Like 15
  2. Personally, if the CA control is what I would expect from the aperture / glass type / focal ratio then it's the star test quality (extra, intra and at focus) that really sells a scope to me and what I think will give a scope the edge in performance, particularly at high magnifications. It says more about the optical quality (ie: figure and polish) of the objective than the colour correction does I feel, although we would like that to be good too of course :smiley:

     

     

     

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  3. Very interesting results Mark :smiley:

    I guess with aperture being part of the CA equation, the 60mm F/6 using an FPL-53 element was always going to be in with a good chance.

    Likewise at 120mm and F/7.5 it takes a triplet, also involving an FPL-53 element to completely control visible CA.

    I'm sure the views are lovely with all of them ! :thumbright:

    Do the chinese scopes use Japanese glass or do Ohara produce FPL-53 in China now as well as elsewhere ?

     

    • Like 4
  4. I've followed a similar approach to others above - my 100, 102mm and 120mm refractors use Vixen-type dovetail bars but the 130mm F/9.2 gets a Losmandy bar. I did use the bigger scope on a strong version of a Vixen-type bar for a short while but decided to move to the larger one and it just seems more solid.

    My refractors are all side-mounted on alt-azimuth mounts.

    I do use better quality dovetail bars though. Those long stock Skywatcher type bars do seem a more prone to flex and vibration.

     

    • Thanks 1
  5. I was loaned one of the Explore Scientific 1.25 inch 2.x focal extenders a few years ago to compare with the Tele Vue 2.5x Powermate that I had at the time. The ES focal extender compared very well indeed quite honestly.

    Personally I like the way that these devices (compared to barlow lenses) have much less, or no, impact on the point where eyepieces reach focus (important if your focuser has limited travel), don't tend to vignette the field edges when used with eyepieces with close to the maximum field stop size, and don't extend eye relief.

    I don't use barlows or extenders much these days but have kept a Baader 2.25x barlow which are basic but quite good optically, for occasional use.

     

    • Thanks 1
  6. Hello,

    Just to complete the picture, can you let us know what eyepieces you currently have to use with this scope ?

    On the performance increases, having often compared the views using both low-mid price and much more expensive accessories I feel the differences are almost always subtle so much more in the 10%-20% area. That's not to say that such improvements are not worth having but I guess I'm trying to be realistic with the gains that can be made.

    Nice scope to own by the way :smiley:

    • Like 3
  7. This was posted on the RAS website earlier this year but I've just come across it:

    https://ras.ac.uk/news-and-press/news/can-you-help-us-find-moon-trees

    They are eager to trace the whereabouts of trees in the UK that were grown on from seeds that flew around the moon during the Apollo 14 mission in 1971.

    Apparently there are no records of where these trees might have been planted even in the obvious places such as Kew Gardens.

    This search was prompted by a question on the "Gardeners Question Time" radio programme.

    Personally, I've no idea but someone out there might be able to shed some light on this ?

     

  8. I've probably posted this earlier in this thread but I was 9 years old when Neil Armstrong walked on the moon and I strongly suspect that the coverage of the Apollo programme ignited my interest in space and astronomy. Actually I suspect it was the reports of the Apollo 8 mission in 1968 that grabbed my imagination first.

    My secondary school had an astronomy club which I joined at age 11 or 12 and that built on the interest. I borrowed a small scope from a friend around that time and observed Jupiter over a couple of months with it.

    The Viking missions to Mars in 1976 also made a big impact on the 16 year old me.

    53 years later, I'm heavily committed to astronomy as a hobby. It won't go away I'm sure, even if I didn't own a scope :rolleyes2:

     

  9. 2 minutes ago, UKDiver said:

    .... and learn how to find targets.

    I feel this is one of the biggest challenges for newcomers to the hobby who do not wish to invest in GOTO mounts. Once the obvious and easy to find targets have been observed and the enthusiasm fired, quite naturally folks want to progress onto slightly more challenging targets but can find this daunting and frustrating.

    I have wondered if we could start a thread or even a sub-section in the observing part of the forum where more experienced observers can post their favorite "star hops" or similar target finding advice, charts etc which can gradually build into a readily accessible resource for those building their experience and widening there observing "repertoire" :icon_scratch:

    I'd certainly be happy to contribute to that (and borrow some as well !) :smiley: 

     

    • Like 11
  10. 7 minutes ago, Dark Vader said:

    Nice! Yep, frustratingly still in their boxes. I thought about the 7 but I'm pretty well covered for 6-8 mm. Gonna check with SWMBO if I can get away with a 24mm Panoptic in a few weeks 

    I hope that short peek though mine a couple of weeks back has not been a bad influence on you :evil:

    • Like 2
  11. I use UHC and O-III filters with my 4 inch refractors and find them effective on a variety of nebulae. For some targets the O-III filter is the only way to get anything much visible in the eyepiece. Using an effective exit pupil is important to the impact that these filters make. I find that 4mm-6mm exit pupils help an O-III filter the most while with a UHC filter I think you can push that to the 2mm - 5mm range. Not hard and fast rules though.

    I don't use an LP filter myself but many folks find the Baader Neodymium filter good for this role.

     

     

     

     

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    • Thanks 1
  12. 18 minutes ago, John said:

    My astronomical aims for 2022 are:

    - To make much more use of the equipment that I now have: it has all got to start "earning it's keep" I feel, or ...... see last aim !

    - To use the facilities at my society observatory more often, especially the 18 inch scope there.

    - To try and get together with others to observe more often as it hopefully becomes more feasible to do so.

    - To share the observing experience with as many people as possible who have little or no experience of looking through a telescope.

    - Depending on how the first of these aims goes, to reduce my equipment level to what really gets regularly used.

     

     

     

     

    I've just thought of another one:

    - Make more of this forum in terms of continuing to learn and making useful input to help others :smiley:

    I think I can do better at this than I have over the past 6 months or so.

    • Like 5
  13. My astronomical aims for 2022 are:

    - To make much more use of the equipment that I now have: it has all got to start "earning it's keep" I feel, or ...... see last aim !

    - To use the facilities at my society observatory more often, especially the 18 inch scope there.

    - To try and get together with others to observe more often as it hopefully becomes more feasible to do so.

    - To share the observing experience with as many people as possible who have little or no experience of looking through a telescope.

    - Depending on how the first of these aims goes, to reduce my equipment level to what really gets regularly used.

     

     

     

     

    • Like 10
  14. 2 hours ago, Dave1 said:

    Yes most of the details you've raised in this thread were detailed in your review and on other threads. Like I said John, I have read your review and every review going. The first example you received is the only one in the world to have been reported as being oval in shape, its also the only one to have been received with a broken lens, I doubt that it left the factory like that, as hard as that is to believe. I do think you where very unlucky in that regard, but it is not representative of Tal products in general. The reason Tal product disappeared from this shore is because the Chinese upped there quality of there optics and QC, that is a remark I was given directly from a retailer when I was thinking of buying one of the last brand new Tal 100 RS in stock in this country, that and the Chinese were doing it at a price Tal could not compete with if all of Tal designs are taken into consideration. Tal like all other Russian manufacturers were asked by the Russian military to make optics under contract, like Intes- Micro. Although Tal and Intes Micro always did make optics for the military, the amateur astronomy aspect of the business was only secondary.

    OK Dave1 but when you see the way that the scope tube is made you will understand why I felt that the mishape was created during manufacture rather than during transit. My comments on dealer attitudes are based on 1st hand discussions as well.

    I've taken up enough of your thread so I'll bow out with my fingers crossed for you but I will be very pleased if your TAL Apolar 125 turns out to be a very satisfying telescope to own and use.

    Maybe I have been unlucky with review scopes - I had two Skywatcher ED150's sent to me for review and both were damaged in transit. Clearly North Somerset is not a safe place to send a telescope ! :smiley:

    • Like 1
  15. 1 hour ago, F15Rules said:

    I think that shipping was a really weak link in the Tal supply chain..it's about a 3,600 mile journey by land from Novosibirsk to London, and I'm sure that the tortuous journey over multiple types of terrain must have accounted for the vast majority of the scopes that arrived here damaged: the "coffin" I referred to above was very solid indeed, and the scope arrives intact, but it had clearly had some significantly rough handling en route!

     

     

    True Dave, but I honestly believe that many left the factory in a poor state as well. One of the TAL Apolar 125's that I received had a welded tube that had the profile of an egg rather than being even roughly round (not squashed in transit - badly formed and welded that way) The 2nd welded seam between the level and tapered sections was rusting and covered up by a black elastic band. The objective cell had scratches all over it as well. The central triplet element had come loose and had smashed which was probably a transit issue but the rest of the scope was not pretty at all.

    The 2nd scope that I received was in better shape but still had plenty of rough edges including some mis-collimation and even though the focuser had a 2 inch format drawtube, when a 2 inch diagonal was fitted, no 2 inch eyepieces would come to focus due to lack of inwards focuser travel.

    At the time I was testing the TAL Apolar 125 I had an Intes 150mm maksutov-newtonian and there was simply no comparison between these Russian products - the Intes was superior every way, fit, finish, design and performance and yet the list price in the UK at that time was roughly the same.

    I understand that dealers in the UK became very wary of handling TAL orders because they knew that the chances of customer issues with them would be high unless they spent a significant amount time checking and prepping scopes prior to dispatch. Most were content to move away from supplying them to customers.

    Good luck with yours though, @Dave1 :smiley:

     

     

     

     

     

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