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johninderby

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Posts posted by johninderby


  1. 1 hour ago, Alien 13 said:

    Are there any good glass filters for camera lenses, I need a 77 mm one that fits the filter thread.... 

    Alan

    Seymour do one but can’t find it in the UK but you can order from Amazon.com and they will deliver it just like any Amazon purchase with no,customs to deal with. Not cheap though.

    https://www.amazon.com/Helios-Solar-Threaded-Camera-Filter/dp/B06X6B32KB

    RotherValleyOptics does the Seymour cell with the rubbish seymour film in it. Suppose you could always replace it with Badder. The film Seymour uses is ND5 not 3.8 as you would expect in a camera filter.

    https://www.rothervalleyoptics.co.uk/seymour-solar-threaded-camera-solar-filter.html

    • Thanks 1

  2. With a regular frac up to 150mm heat is no problem with a wedge. The glass at the front doesn’t get warm as  the Sun's light is not yet concentrated/focused at the objective end. Neither does the focuser. All the heat such as it is goes into the wedge. When I’ve used a wedge  no part of the scope except the wedge gets even warm.

    Yuri from TEC telescopes recommends using a wedge with TEC refractors.

    • Like 2

  3. Think the Baader solar film is the best available so would probably be a bit better than the ES film. Tried the Seymour film that gives a yellow sun but chucked  it in the bin after one use. Just rubbish compared to the Baader.

     The problem with glass filters is that they aren’t optically flat unlike the Baader film so have more distortions. An optically flat piece of glass is horrendously expensive to produce and the cheap glass used by Orion, Thousand Oaks etc isn’t optically flat. Zeiss used to make proper optically flat glass solar filters but even second hand they can go for £1,000.00 and up. 

    • Like 1
    • Thanks 1

  4. One aspect to street lighting and safety that would be effective is dimmed lights on most of the road and regular lighting at intersections. That way it’s more obvious that you are approching an intersection. 

    Can’t remember where I read that though but seems like a good idea.


  5. The continuum filter is stacked with the ND3 filter in a single screw in filter housing so it can be removed and be replaced by a standard plain ND3 filter. You must never use a wedge without an ND3 filter fitted.

    The housing gets warm but not too hot.

    Performance is the same as the Lunt wedge so I’d only ever buy a second hand Lunt wedge.


  6. Perhaps magazines should just accept that they aren’t the best place for images to be seen and concentrate more on equipment reviews and how to articles etc. and have a website to properly display images. They could then show a web address for an image along with the printed photo.

    Perhaps a first time submission section for beginners would help. 🤔


  7. One problem to be aware of with using a lazy susan bearing is it will turn too freely. You may want to add some friction. I found using teflon pads as in a standard dob setup and shimming to just add some resitance to turning helped and made the movement smoother.


  8. Altair TMS Heavy Duty Losmandy / Vixen Saddle Clamp

    As new.

    Was going to use with a Rowan AZ100 but now that they will be offering a dual fit saddle the Altair is no longer needed. 

    Save £50.00 over buying new.

    £79.00 Collected - UK postage £5.00

    Heavy duty saddle plate which is compatible with both the Vixen/Synta-format telescope mounting bars, or the Losmandy-format wider mounting plates. This all-in-one design means you don't have to change clamps for different telescopes, making your mount more compatible. 

    Payment by PayPal (buyer pays fees) or Bank Transfer. 

            John

    4EA83224-63C0-4E80-9D3B-70D4658489D6.jpeg

    C4AAB88A-A195-47DF-8FA8-01E781B6CD69.jpeg

    0546B5ED-0409-4583-A1D9-30CA95939A13.jpeg


  9. I have to correct you there. I have tried a number of binoviewers on some very fine scopes and despite being “optimised” still prefered the one eyed observing. And it’s not just me. Many very experienced observers have found they don't like binoviewers. It’s just a matter of personal preference that’s all.

    They may work for you but not for everyone. Peoples eyesight does differ so you can’t make the sweeping assumption that your opinion is correct for everyone..

    • Like 1

  10. Yes the ADM are a matt finish that that wouldn’t match the mount. 

    Hopefully the Altair dual saddle that I already have will  match. Did replace the stock knobs with some stainless steel ones that are far easier to tighten up.

    CB830E68-4CB6-46CF-80B3-DE54A28BC3DA.jpeg

    • Like 1

  11. I’ll be using an Altair dual fit saddle and Rowan have provided plenty of mounting holes so the ADM should be fine. They have added a couple of M8 holes on an 80mm centre that aren’t shown on this drawing.

    49899763-2E9E-4F5F-887C-884977AA7E10.png


  12. Yes Alan I am indeed looking forward to receiving my AZ100. 🙂

    I’ve dealt with Rowan before for some non astro bits and they were very accommodating in making changes to suit me. Good old British engineering. Those Americans on CN will be so jealous. 👍🏻👍🏻👍🏻

    • Like 3
    • Haha 1
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