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steppenwolf

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About steppenwolf

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    http://www.skyatnightimages.co.uk

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    Nr. Wiston, West Sussex
  1. Actually, Olly, I'm with you here, the tangent arm is an amazingly simple piece of engineering that provides an unbelievably infinitesimal amount of movement of the focuser knob - just what we often need for accurate focus! What I REALLY love about the tangent arm is that you can further increase its resolution by increasing the distance of the arm from the centre of rotation and the sky is the limit here! Digital? Pah!
  2. That is rather what I am hoping, Olly, as I can confirm that trying to focus one of these by hand on the focus ring is very difficult - I developed a way of doing it by 'brushing' the focus ring but even that was a bit hit and miss. The motor/gearbox I am using here produces 2,880 steps/revolution at the small gear end and this is, of course, stepped down further dramatically via the belt drive ratio. I can now adjust the focus using a 'jog' control in single or multiple steps so am confident that it will work really well manually - what I don't know yet is whether or not it will work well under autofocus control but in theory, it should work fine, it is just a matter of choosing the right magnitude star for the software to work on. For an astro-photographer like you @ollypenrice who prefers manual operation, this should be a great way of doing it.
  3. I can think of no reason why this would not work on the zoom although this is a greater load than that of the focuser - that said, this motor produces a high torque with its 60:1 reduction and it happily pulls my FeatherTouch R&P focuser loaded with a 1.6Kg weight!
  4. Luckily, I am saved from the embarrassment of doing that as this is a fixed telephoto lens - but it would have been hilarious to get this wrong if it had been a zoom! Thanks, Stu, I'm looking forward to hitting the band of the Milky Way with this in the summer.
  5. Cloud, cloud and more cloud – but looking on the positive side, this presents an opportunity for a ‘project’. Now, I’ve already done the observatory ‘spring clean’ – I even have the photos to prove it – so I thought I’d tackle a project that has been on the back burner for years; auto-focusing my camera lens(s) for wide-field imaging. Despite two attempts at putting the TS Telefokus 105 microfocuser on my Christmas list so that I could accurately focus my Canon 200L telephoto lens on the stars, there were no takers so the project stalled. However, having bought a second motor for my existing autofocus controller to install on a new telescope got me thinking that maybe this would actually be a better way of controlling focus and might even allow autofocus during a long imaging session to compensate for temperature changes. So, I put a third motor on my birthday list and my two sons clubbed together to buy it for me moving the project forwards! Yesterday, I completed it with the addition of a finder-guider that I had in my ‘goodies’ box that is normally used for guiding short focal length review telescopes. Now, in fairness, it is untested on the night sky (cloud, remember, hence the project!) but what I can tell you is that the focuser moves in invisible increments or quickly as required, is ultra smooth and shows no sign of slipping! Unfortunately, much as I’d love to, I can’t install my mono camera as, with its built in filter wheel and OAG, there is insufficient back-focus. This means that the system will be used with my OSC SXVF-M25C coupled to the Canon 200 L lens using a custom adaptor I had made when Adam was a lad. What could possibly go wrong? Front View The two pictures above show the 72mm lens has been stooped down to 52mm using a step-down ring. This reduces the aperture from f2.8 to f3.8 to improve star shapes at the periphery of the FOV but without adding the diffraction spikes that would be a feature of stopping the lens down using the iris. Belt Drive Finder-Guider Connection
  6. Thanks for the heads up, John but sadly West Sussex in is under cloud
  7. Yet another lovely example of why remote imaging has such appeal. Very nicely processed indeed, Steve.
  8. Did you just take the lens cell out leaving the two lens elements attached to one another throughout or did you actually separate the lens cell into its component parts so that you had the two lens elements apart from one another?
  9. I have to say that my understanding of using a Quark with a Petzval design is that you shouldn't! The 106ED is a lovely instrument so tread very carefully here because its loveliness doesn't extend to use as a doorstop .....
  10. That is always an exciting start point as you know the project is really under way!
  11. The Gimp would be a good choice, it's free and feature rich. Unlike PS though, it is currently an 8 bit depth program although a 16 bit version is apparently just around the corner.
  12. Hi Alec, I don't have a deliberate pier offset as it just isn't necessary as the Pulsar shutter opens past the zenith. If you have a really large aperture telescope, then it may be more of an issue but my 100mm and 150mm refractors are fine with a centre mounted pier - I am a bit of a nerd when it comes to 'symmetry'
  13. Ask away Alec, there are plenty of knowledgeable people on here to help!
  14. Hi Alec, Assuming that previously you have controlled your AZ EQ6 GT using EQASCOM (EQMod) then the easy way to check is to call up whatever software you use to control your mount and check what the software says is the connection method - normally there is a Tab headed 'Telescope' and you connect your 'telescope' there. If the connection says something like EQMod ASCOM HEQ5/6 then you are connecting directly to your mount but if it says POTH then you know that you are indeed using POTH. If POTH is shown as your connection then you can click on 'select' and that will tell you what POTH is subsequently connected to - most likely EQMod ASCOM HEQ5/6. POTH just works as a 'hub' which can be very useful in its own right but it does also include the dome 'slaving' feature discussed here. I hope that helps!
  15. That's pretty much the case but for it to work, both the dome and the mount must be controlled via POTH so instructions to move the telescope must be ASCOM derived via POTH.