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UKAstroBill

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About UKAstroBill

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    Oxfordshire
  1. Guidescope option looks wimpy. I think my Asiair Pro kit has a similar spec one and I got that to see if I can improve tracking on the SkyGuider Pro.
  2. On this same issue I do not want to modify my CEM40 as I want to switch regularly between single and dual operation. Is there a side by side kit that (a) comes with a dovetail fitted to the cross bar at right angles, that dovetail pointing in the same direction as the two telescope mounts; (b) the two mounts have brackets supporting both Losmandy and Vixen (c) one side can be adapted to finder/guide shoe, preferably with directional adjustments? Maybe I’m being lazy, but I just want to be able to swap between one and two with no fuss. I’m pretty sure I could do it with ADM parts at huge cost, but what I’d like is an affordable complete kit that preserves all the orientations.
  3. I’ve had the Astro Hutech part for a few weeks now and am really pleased with it. The optical length calibration for IDAS filters is perfect and the body lens interface is rock solid. Mine is the one coupling Nikon Z bodies to Nikon F lenses and it has a mechanical control for adjusting aperture on G type lenses. So you can adjust aperture from the adapter on non E Nikons and 3rd party lenses from Sigma for example. It’s calibrated for the IDAS range so that’s for filters that are 2.5mm thick. Thinner filters from other manufacturers will usually fit but you might not be able to achieve infinity focus as the optical path is too long. That’s not a fault in the design so much as the fact that AH have tuned the part to work perfectly with the par focal IDAS range. It works brilliantly with the IDAS set.
  4. Just looking at adapting one of these to an APM 107/700. If anyone has done that I’d be interested to know what adapters people used and if any spacing issues arose. Looks like I can go from m82 to m68 then to the m68 adapter starizona sell. I have m82 adapter Already on the focuser to take the Riccardi FF. in passing I note Starizona sell a 2in extension as necessary for the Esprit 120/150. Presumably this is a recent addition given comments above. If anyone has one of these on a scope around 100-110mm I’d be keen to see a flat taken on 35mm sensor, or better still a 1:1 24mm x24mm square crop from full frame. That’s what I shoot with using the Starizona SCT Corrector III that has a nominal circle of 27mm. It’s a bit of a stretch to the 34mm diagonal of that square but I can do it with flats at the price of noisy corners. The Apex claims 30mm circle so maybe rather better in that plan. With the 0.65 if that works I’d prefer it to the large Riccardi 0.75, which is the standard option. (I can use the Apex also on another scope.) Views very welcome!
  5. 533 is looking very attractive to me not just on price and amp glow but because it is square. Square sensors make a lot more sense for astro. Limited circular fields of illumination are best utilised by square sensors and there is no up in space. I just wish it was bigger. 20mm x 20mm would suit my scopes best and I’d like the lower noise of larger pixels.
  6. Borg responded with the useful detail that their filter adapter has an optical length of 31.3mm and is designed for IDAS filters, of thickness 2.5mm and refractive index 1.5168. So they have decided to calibrate well for a certain thickness, which makes a lot of sense. I’m ordering one and will try it out in comparison with the 2 inch version of FAstroTZ.
  7. All kinds of possibilities. Just make sure that when you screw in a filter it is clear of the sensor and the end of the lens. The Geoptik has plenty of clearance to ensure this and I screw the filter assembly well in to be clear of the lens. 1.25 is plenty for a 4/3 or DX sensor. meanwhile Borg have confirmed their part is fixed length and indicated they designed it with IDAS filters in mind. I hope to get more details after Thanksgiving. Don’t know the optical length yet.
  8. Space Oddities: I think it would be sensible for me to compare the Borg device to my 2inch prototype when I get to the next stage. I’ve emailed AstroHutech to ask them some questions especially about its optical length. Eg is the fixed length the same as the FTZ or is it calibrated at eg around 2mm filters with a larger optical length. Can you tell me what lenses you Use it with and what the image quality is like edge to edge? When I first built the 1.25 gadget I calibrated it to the FTZ by matching infinity focus without filters. When I put an Optolong l enhancer or Baader Halpha in the image quality was good edge to edge on the Nikon 200-500 but poor on wide angles. I mean that if you focused in the middle the edges were fine on telephoto but way off for wide angle. Adjusting the spacer up to allow for the filter made a big improvement for the wide angles, especially UWA zone. So I’m curious how well you find a fixed length part works at various focal lengths. If you have time! I’ll probably buy it anyway to compare once I’ve heard back from them.
  9. I’m not sure if direction matters! For a filter where it is the body of the material that does the job it can’t matter. I’ve been a bit anxious about whether a more complex layered design would be sensitive to it. Both the contraption in the video and my 2 inch prototype have the filter “right” way up but for the 1.25 case that was more to do with moving the filter away from the lens to kill the vignetting as much as possible. I’m more concerned about getting the right Backfocus though. A couple of days ago I spent some time calibrating the infinity focus on my gadget to various or no filters. The device seems to be a bit wider than the manufacturer data suggests and it was calibrating to close to FTZ infinity focus with a 0.8 mm spacer, and 1.4mm nailed it for the Optolong L enhance, with the Baader Halpha wanting a tiny bit more, though I left it at 1.4.
  10. Thanks Mark - There is some discussion of this in the video. On the Nikon 200-500 there is hard vignetting at 500 but the 1:1 crop is fine. On a dedicated telescope you would almost certainly get the same. On my scopes (an APM 107/700 and a Celestron C6 with reducer) I have 2 inch filters in line and just do not use this contraption.
  11. That's great for the 2 inch case - thanks for pointing this one out. I was hoping this post would turn something up. Costs a bit more than my contraption though. My main concern is whether it allows adjustment of the back focus distance for the effect of the filter? I've been doing some focus fine tuning and have discovered that if you do not correct for that you have to focus quite a bit short of where infinity was in the ordinary FTZ.
  12. Weather in UK is dire at moment. Biblical rain. I’ll get out eventually. But on the matter of “need” there are all kinds of projects. I picked up my Halpha filters today at the Astronomy show with a view to seeing if I can synthetically astro mod the Z6 in a less crude way, given that it appears to capture a bit over 20%. The layout is great and having focus peaking give you a first fix is amazing.
  13. The weather has been so bad I have had the time to finish a video on using astro filters with the Nikon Z bodies and Nikon camera lenses. There is a manual alternative to the FTZ allowing 1.25 inch filters to be fitted between camera and F-mount lenses, and for some lenses and end of lens solution make sense. FAstroTZ is described here:
  14. Six years later and same problem. Have cut mine.
  15. I've got the Geoptik working with various Nikon and 3rd party F-mount lenses. I have had no problems keeping the aperture wide open. 1. There is a pin in the Geoptik that holds the aperture wide open for those lens that support mechanical aperture control; e.g. Nikon 20mm f/1.8; Samyang 12mm Fisheye, Sigma 35mm Art 2. For lenses like the Nikon 200-500, the pin does not work, but if you detach the lens from a camera before turning the power off the aperture stays in the last position. I have had no problems using this at f/5.6 on the Geoptik. Nothing bad has happened to lens or camera doing this. My issue with the Geoptik is its attaching mechanism, my least favourite. Hard to see why they could not have a secure click option rather than the annoying orange tightening screw. *** QUESTION *** But I do have another question about the Cyclops Nikon lens adapters as I am looking for 2 inch compatibility which the Geoptik does not have. Can any one tell me the camera side interface, in terms of thread AND gender and depth if you know for (a) the Cyclops Blade-N Nikon gadget (b) the simpler M54 Nikon adapter (part 020073) (c) the simpler M42 Nikon adapter (part 020074) For the last two it is obviously the gender I am after! By the way, if anyone has a Nikon Z and some F mount glass, the Baader wide T mount for Z attaches to the Geoptik and lets you have 1.25in filters in line. They screw together to create an optical path about 1.2mm shorter than the Nikon FTZ, but it allows the filters and you can space it out if you are fussy. Thanks William
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