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About Jessun

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    Lyon France
  1. Drift in RA Axis?

    Hi! You get rotation from misalignment with true North. The mount can't somehow turn the scopes in their rings, or twist internally. It doesn't matter where you point with your guide scope, within reason. If it wasn't for the atmosphere you could point it anywhere. BUT if you have either the main OTA or guide scope approach the horizon way before the other one, then the atmospheric diffraction will cause an apparent drift in the resulting image. So long as they appear to roughly point in the same direction you'd be fine to image horizon to horizon. I think you have differential flexure, or perhaps the camera end is responsible for it through the adapter etc. My assumption would be that you'll see trailing if you increase your exposure to 20-30m. Flexure can be tricky to fight unless you're opting for an OAG. But if this current setup produces a totally workable stack then don't worry too much. /Jesper
  2. Show us your set up in action at night.

    The beauty that was turned into an R2-D2 that had been through a traffic accident... Basically moved flats and didn't need the overhang anymore... /Jesper
  3. Show us your set up in action at night.

    Yes, in a way. It paved way for the triple rig and taught me most of the basics that I still use. /Jesper
  4. Show us your set up in action at night.

    This is what I ran for some years, with the mount and OTA hanging a foot over the edge of a balcony rail. Learned a lot from this experiment. /Jesper
  5. Go here, as an example http://www.newastro.com/book_new/camera_app.html and play around until you've found your sweet spot, regarding resolution, speed and price. /Jesper
  6. Worst I ever owned ;-)
  7. Knowledge is virtually free these day. Why on Earth would you want to pay for it? After a while you'll develop you're own style anyways following YOUR work flow so that your images are unique. /Jesper
  8. This is not so. Just keep the focal length and open up the aperture, either by a bigger lens or a mirror. /Jesper
  9. Here's the rig btw setup in Provence. A springy iOptron carrying much to much weight and a difficult RC scope, but Olly pulled something out of it despite all the shortfalls of my setup. /Jesper
  10. BTW a somewhat quicker method is to visit someone who have some years of practice already. I remember my first visit to a certain Olly Penrice, as he chucked my sub par data of the night into his PC and like a Jedi pulled out colour and detail beyond what I could comprehend. I will never reach his level, but the kick start this visit provided was price less for an amateur like me. /Jesper
  11. +1 for YouTube. Any software out there will have hours worth of clips on there, for free! /Jesper
  12. I see what you're saying of course, but in the world of no free lunches, the ED80 is at least a free starter in terms of the lens. For some reason it hit the jackpot for the price range. Good luck hunting! /Jesper
  13. fraudulent imaging

    I used to like this screen a lot from indoors. Nothing wrong with being remote :-) /Jesper
  14. The little ED80 with upgraded focusers rendered me 6 AAPOD in one year.
  15. Rotation after meridian flip... why?

    In my opinion, for it is nothing more, a flip simply flips and mirrors (turns it upside down if you like) so any camera misalignment is doubled. If you're leaning 5° to one side in the draw tube the resulting stack will have a 10° discrepancy between pre and post flip subs, so the black triangles show up along the edges. What causes the misalignment in the first place could well be all sources of cone error tricking you to think that the camera is aligned with RA and Dec on that side of the meridian. PS - I take this all back. It's not the case... Camera retains orientation as good as the mount can do it after the flip. Perhaps it lies with internal bearings or axis alignment allowing a little tilt or something else not squared up internally. /Jesper