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About Starwiz

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  1. OK, thanks. That makes sense. John
  2. That's probably the point I'm missing. I need to get both the main camera and the OAG in focus. I'm using the standard focuser that comes with the SW200p, but I'm now wondering about the extra distance caused by the filter wheel, so would I need to mount the OAG between the wheel and camera? Thanks John
  3. I'm not using a coma corrector at the moment. I'm currently using a 21mm spacer with the 1600mm-pro, which leaves me with spare 15mm outward travel and 21mm inward travel on the focuser (as per the diagram below). The OAG is 16.5mm thick, so would replace the 21mm spacer, leaving me with spare outward travel of 10.5mm once focused, unless I'm completely missing something (which hasn't been unknown in the past). Thanks John
  4. Thanks. An interesting article on the differential flexure, so I'll have a good read. I scrolled down on the content of the link I originally posted and the example set-up shows a Zwo 120mc being used with the OAG, so I guess my question is, does anyone else use it with this OAG? I'm also wondering if if makes a difference with what scope is being used (F-number) as the OAG is tapping in on the light from it? I'm using an F5 SW200p. John
  5. Thanks. I'm using a Zwo ASI1600mm-pro plus filter wheel for imaging and a Zwo ASI120mc for guiding, so I guess it should be compatible. John
  6. I suspect I'm getting a bit of flexure during parts of my imaging sessions. There is slight star trailing despite the polar alignment and guiding data looking very good. I'm thinking about getting an OAG. Does anyone have any recommendations and is this one any good? https://www.firstlightoptics.com/off-axis-guiders-oag/zwo-off-axis-guider-oag.html Thanks John
  7. It's been almost a year now since I switched over to mono and don't regret it. As Olly and others have said, the overall capture time is quicker with mono than it is with OSC. I've found the processing time is longer with mono as you can have as many as 5 sets of data to process in the instance of HaLRGB, but it's something enjoy when the conditions aren't suitable for imaging. John
  8. Well done. It just goes to show you can still get results with the full moon out. John
  9. This isn't working for me. I have a recent batch of Ha frames where it was only stacking 43 frames out of 118. I've just tried using a lower scoring frame as the reference and now it says it's only going to stack one frame. Perhaps the stars just aren't good enough. John
  10. Congrats on an excellent first image. Fast forward another 4-5 years into the future and you will be waiting for another 10 hours of Ha data to finish off an image that you can't shoot at the moment because the moon is too bright. It starts off small, but then the desire increases.
  11. Thanks for the replies. Here's a frame that's not stacking.
  12. Has anyone tried manually stacking frames? I have about 120 Ha frames of M82. The galaxy data looks good, but DSS is only stacking about 40 frames - it doesn't seem to be detecting enough stars even though I've tried different thresholds. Thanks John
  13. Many thanks. I did wonder, but don't remember it looking this bad before. John
  14. Under a near full moon last night, I ran some trials in Ha on the Heart Nebula. On looking at the images this morning, I'm seeing some strange star shapes towards the corners of each image. Image shows the magnified stars. SW200p, ASI1600mm-Pro, EFW filter wheel & Zwo Ha Filter 31mm. Any thoughts as to the cause. I collimated the scope beforehand. Thanks John
  15. Using a mono camera doesn't really take any more imaging time than a one-shot colour camera. With each filter of RGB, the exposure time is around a third of the time for the one-shot colour camera as all the pixels are in play for each filter. The bayer matrix filter in the colour camera means the pixels in use for each channel is reduced. I remember Olly Penrice posting about this in the past with a more knowledgeable description than I can give. I have found, however, that mono requires a lot more processing time afterward due processing each channel separately. John
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