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rwg

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Everything posted by rwg

  1. @DuncanM Actually the numbers are just 'nice to have' you can do the polar alignment without using them at all as long as you put the indicated star into the target crosshairs by adjusting the alt/az bolts. The distances in Alt and Az are based on an estimation of your longitude from your time zone (15 degrees west for every hour behind UTC). If your true longitude is more than about 15 degrees out from the estimated longitude then the alt/az figures aren't going to be as accurate. cheers, Robin
  2. Just to say to everyone that getting the polar alignment error down to a few seconds of arc is really unnecessary (although fun...)! If you took a six hour exposure then the total amount of drift due to polar alignment issues (as opposed to other things like tracking rate inaccuracies) would be roughly the same as your polar alignment error. If you are taking 5 minute exposures then the drift due to polar misalignment will be 72 times smaller, so getting within 1-2 minutes of arc should be fine for 5 minute exposures. cheers Robin
  3. @michaelmorris It would definitely be possible to add direct support for the lodestar - probably wouldn't even take more than a couple of evenings to do if I had one to play with. Trying to add a new brand of camera without one to work with is a pig of a job - no matter how good the documentation there are always things that aren't included that you have to find out by trial-and-error and that doesn't work well if you are sending repeated trial builds to some long-suffering tester who has the camera. Of course the other thing that it needs is time, which I seem to be incredibly short of recently cheers, Robin
  4. Hi Doug, not sure if anyone has ever tried it this way, but I can't see any reason why it wouldn't work - worth a shot. cheers, Robin
  5. Failure to solve in one orientation is usually a result of either not enough stars being detected or hot pixels being picked up as stars and ruining everything. Best thing to do is to leave the scope in the problem orientation and restart the polar alignment procedure. On the first page you will see lots of controls that allow you to tinker with the star detection parameters. Hopefully playing with one or more of those will get you going. Also have a try with increased or decreased exposure and/or gain. If all that fails then save a frame or two and fling them in my direction. cheers, Robin
  6. @Horwig I guess you are using the ASCOM driver for the Lodestar - sometimes that can lead to odd effects when the ASCOM driver does things in a way that SharpCap doesn't expect (like some ASCOM drivers claim that colour sensors are really mono, etc). Seeing a frame would help, but if you have a colour sensor but see a mono image and can see a grid pattern when you look at the pixel level, try playing with the 'Debayer Preview' control to force debayering - one of the options should look right colour wise. cheers, Robin
  7. When you are seeing the 'Step 1' UI there are a whole range of options that you can tweak to adjust the parameters for star detection - have a play with those and you will probably be able to fix the problem. If not save a couple of sample frames and send them over. cheers, Robin
  8. Could you post a screenshot showing the issue. It would be very helpful if you could capture a pair of frames (one in each orientation) and share those too. cheers, Robin
  9. The meteor lens is much to wide angle (too short a focal length). Recommended focal length for a GPCAM or equivalent sensor size is 200mm (finder guider) - this gives a 1.2 degree FOV. 100m should work (~2.5 degree FOV). 50mm has a chance of working (~5 degree FOV) but is untested as far as I know. If you don't want to go down the finder-guider route, it might be worth looking into cheap 2nd hand manual focus zoom lenses for SLR cameras (say a 70-210 zoom) and an appropriate adapter to attach to a C/CS mount. I have a Pentax 70-210/4 zoom that I use for camera testing and 3d printed a GPCAM adapter for it (https://www.thingiverse.com/thing:1838091) cheers, Robin
  10. I have been trying to work out what the problem is with adjusting before moving on (both in practice and theoretically), and I think I have finally worked it out... If you start adjusting before you move on to the last phase then you notice that as you adjust, the position marked in the frame for the RA axis starts to move. This is wrong... The position of the RA axis within the frame is determined only by the alignment of the scope and camera you are using to the mount RA axis. Moving where the RA axis points in the sky should have no effect on the position of the RA axis within the frame. So, basically, by adjusting before the final stage you are confusing SharpCap's calculation of where the RA axis currently is, which in turn throws the alignment off. cheers, Robin
  11. No, the field of view is going to be too wide with that lens. You might be able to find a 40-50mm CS lens on ebay that would might get you (just) to a small enough field of view. The 2.1mm meteor lens is just too wide angle. cheers, Robin
  12. @Horwig glad to hear it is working for you. The early versions (2.8) had some problems with large fields of view and too many stars as well as with too few stars. That's fixed in 2.9, so you will only get problems if the FOV is too small and there are not enough stars that SharpCap recognises in the field of view. cheers, Robin
  13. Either way will work fine - take your pick. cheers, Robin
  14. This is a good question and one I don't yet fully understand. The plate solving to find the position of the pole is accurate - just tested with a star field from Stellarium with the equatorial grid still in place and you can see how well it does - SharpCap ignores the blue equatorial grid from stellarium easily and puts its own NCP (green) spot on in the right place. If you test when you have finished polar aligning in SharpCap by turning the mount on the RA axis, you should see the stars in view rotate around the point marked as NCP - this confirms that you are correctly polar aligned as the center of rotation is matching the NCP. So... what does that leave? The only thing I can think of is physical flexing of the tripod/mount/pier as the load moves from the 'home' position with scope up and weights down to whatever position you run a drift align from. To be honest, I'd have thought that this shouldn't happen if you are have properly balanced the mount payload, but I'm not 100% sure. If this is the problem then you'd expect to see less change with a lighter load on the mount. Any further thoughts on this welcome! cheers, Robin
  15. Hi, sorry, no official documentation I'm afraid beyond the web site, the tips at startup and whatever you can find on the forums. When there's a choice between adding a new feature and writing documentation I pretty much always choose adding the new feature! I did have a couple of people volunteer to help bring together some of the info in various forums into documentation, but it all fizzled out I'm afraid cheers, Robin
  16. All of the camera settings are saved in a .CameraSettings.txt file next to the actual capture file, so the data is there if you want to use it. cheers, Robin
  17. Hi, currenly there is no framing feature - I don't see it as something I'm likely to add in the near future I'm afraid. I guess I imagine that sort of thing being done in post-processing. cheers, Robin
  18. Chris, yes, the artificial horizon thing replaces the arrow when the arrow becomes so short that it would be difficult to see clearly. Gina, glad you like SharpCap. No real chance of a Linux version I'm afraid - it's all too linked into Windows UI, camera SDKs, etc. cheers, Robin
  19. That's good to hear! I'm working on a major update to the plate solving code which is the core of the polar alignment. The new code should be faster and more accurate too, and should also get a solution for the pole position in many cases where the current code fails. This should give some useful improvements and help to procedure work with a wider range of cameras and focal lengths. One thing I've just discovered is that it doesn't work if your pixels aren't square - in other words it will fail if the camera image is squashed or stretched in the horizontal direction. For most digital USB cameras this won't be an issue, but if you are using a frame grabber with an analogue camera this could cause problems. It might be worth trying different resolutions in the frame grabber (ie 720x480, 720x504, etc) to get one that has an aspect ratio most closely matching that of the camera sensor. cheers, Robin
  20. Hi Dave, I don't think I've tinkered with anything that would address problems with that particular camera, although I did make a couple of tweaks to ASCOM camera support to get some old QHY cameras working. Maybe just the clean out and re-install did the trick? Anyway, glad to hear that you are up and running now! Robin
  21. Hi Andy, really shouldn't matter, as you are pointing pretty much at the pole and you will be taking exposures of a few seconds. Nothing in view is going to move significantly in that time. cheers, Robin
  22. @saac The mono camera would likely be a good choice - you need to work out your FOV (there are several web based FOV calculators out there). As long as your FOV is between about 1 and 2.5 degrees in each direction you should be fine. Ideally you want to see about 10 or more stars, although you might get results with 5 or 6. I haven't consiidered using this with a polarscope - it would be interesting to test - you would need a camera with a lens on it fixed over the eyepiece of the polarscope. No idea how the FOV would work out for this. I've generally considered using this with a finder scope to give the correct FOV, but you could use it with the main scope if the focal length is short enough or the sensor big enough. I've not used a polemaster, so I don't know if it works in the same way as the SharpCap alignment - I guess that they both get you to the same end point. cheers, Robin
  23. Glad to hear that it's working well for you! If you have any problems then please capture a pair of images (one in each orientation) and send them to me - I can use them to help improve the polar alignment and star detection routines. cheers, Robin
  24. Yes, the ZWO will work fine as a guide cam, but don't worry about that just now - as Peter points out you need a second camera for that to work *and* an EQ mount. Save that option for later and get some experience using the ZWO for imaging on your current set up for now Robin
  25. Strictly true, but being a goto mount the OPs mount will follow the target across the sky (how well it does this depends on the quality of initial alignment setup). This is going to be good enough for a go at deep sky video astronomy. I'd suggest the following... For finding the target and focusing turn the gain up high and set an exposure in the 0.5-2s range. The noise caused by high gain doesn't really matter to you - you want to see the effect of any changes you make quickly. For actually taking the image, turn the gain *down* and set an exposure in the 2 to 15s range. The length of exposure is determined by how well the mount tracks - if the stars aren't round, turn it down. Use SharpCap - download the latest beta version and use the live stacking option from the top toolbar. In this mode SharpCap will automatically align and stack each frame as it arrives. This will take care of any field rotation caused by the AltAz mount and movement between frames. Note that there is a bug in the latest beta that causes a crash if you try to 'Save Stack as Viewed' - will be fixed in the next version over the weekend hopefully. cheers, Robin
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