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hello everyone. I bought a meade lx85 and a meade 8 inch f5 newtonian from a friend. Before me, the telescope was used with 1 counterweight and without the balance (it needs 2 counterweights to balance it) so the telescope is shaking a bit in some places. gears may be slightly damaged not sure. and i have a problem. When I attach a camera to the telescope, the shape of the stars starts to become straight lines after 10 seconds. and after a while it goes out of sight. i wonder why that is. There is no autoguider. And when I touch the telescope it shakes a lot, is that normal? I am currently using 2 counterweights and balanced. Things I've tried -Trying to get better polar alignment even though it's not a polar scope -PEC -Ra-Dec Train -Alt-Az Train -Reset the hand controller - Tighten the screws in the mount -Making finer weight balance What should I do to fix this problem? I wonder if the results will be better if I use autoguider? Thanks for any help. |
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 this is one of my best tracking(1 60sec exposure) |
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(scratching head) Dang! That being said, in my experience, that sub image is not far out of line for tracking-without-guiding. Others will say they can go 3 minutes without guiding, but I've never experienced such performance. I get streaks like this in 30 seconds some nights. All improves tremendously with guiding and I can do so indefinitely, resulting in nice round stars (on a good night). But that's with an equatorial mount and may not apply to you. An interesting clue is that the streaks are the same across the image and don't trace a larger circle. And there's the slight introduction of a slight curve within the streak. |
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| If that is a 10s unguided image than, at your image scale, this shouldn't happen (unless your PE is of the order of 1') IF you have carefully polar aligned the mount, which I suspect isn't the case. The lx85 does support a polar scope but I assume yours hasn't got one, isn't it right? So you need to learn to do it without one before you take any image. If you need guidance let me know and I'll post a guide on how to do it without anything other than either a camera (and computer) or a high-power eyepiece. |
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An easy way to polar align this mount is to use a PoleMaster camera. The mount is compatible with the Skywatcher adapters for the PoleMaster and if you switch the mount on day, you can reuse PoleMaster on that new mount. What you're likely seeing is periodic error of the RA axis. Forget about PEC in the LX85, it doesn't work (there's a software issue). W.r.t to the LX85 mount there's also quite some information on CloudyNights. You might want to check this out. Björn PS: I strongly recommend getting an auto guider. Especially for the LX85. PPS: After reading your post again, I am not sure how you did polar alignment. @andrea tasselli might be right with polar alignment. It could also be significant DEC drift if you have a really bad polar alignment. The polar alignment through the handbox isn't accurate by the way. |
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Dave Rust: In fact, there is not much issue in this image. For example, last night I got 30 seconds longer star than this. |
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andrea tasselli: Polar scope did not come out of this box. As I said, in 13 seconds, the shape of the stars starts to distort. And after a while it goes out of view. I think the not so good polar alignment dont be just as effective. I think it's a problem because when I center the star from the camera, it slides right off and then slowly starts to slide off. And I would be very happy if you could help  |
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BjörnBu montajı polar olarak hizalamanın kolay bir yolu, bir PoleMaster kamera kullanmaktır. Montaj, PoleMaster için Skywatcher adaptörleriyle uyumludur ve montajı gündüz değiştirirseniz PoleMaster'ı o yeni montajda yeniden kullanabilirsiniz. will autoguider solve my bad tracking problem? what about the probability of a problem with the gears? |
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An auto guider won't do wonders if the polar alignment is completely off and/or if there would be issues with the gears. Before we'd consider gear issues, can you let us know how you do polar align the mount? |
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will autoguider solve my bad tracking problem? what about the probability of a problem with the gears? You need a moderately well polar-aligned mount for the auto-guiding to be effective. In fact I think is the most significant parameter shortly followed by Dec backlash for auto-guiding performance. And it is very very unlikely that the gears have been ruined by using a unbalanced mount. Guide on how to polar align without anything other a camera or an EP will follow shortly. |
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Just get a autoguiding setup. I would go for the ASIair plus or mini with an ASI120MM mini (for example). I don't know if you want an OAG or guidescope. Everything will be easier and even somewhat fun with the ASIair. You can also get VERY precise polar alignment with this setup. |
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| The only big problem about the ASIair though is that you will be forever stuck with ZWO products. NINA is another option. |
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| Thank you very much for your answers. I'll let you know if there are any developments. If you have any other suggestions, I'd love to hear |
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How to polar-align (in the Northern Hemisphere) a Newtonian telescope without a polar scope or any other overpriced gizmos. 1. First make sure that the finder is aligned with the optical axis of the scope which can either be achieved by pointing the scope to a far away feature (several km away) or using the Polaris itself. If you don't have a finder scope then ignore this. 2. Eyeball the position of Polaris as well as you might by either peering through the bore for the polar scope or using any suitable reference on the mount itself and move the mount so that you get it your sight by just displacing the mount. 3. Make sure that the counterweight bar is pointing as down (toward the ground) as possible. Mount the telescope on the mount and adjust the DEC axis so that is directed toward Polaris. Make sure that the azimuth adjustment screws are evenly positioned (so neither to the left or the right of the center position). 4. Peer into a low power eyepiece and see if you can see Polaris. If not adjust the altitude screw so you have it within the EP FOV. If you have a finder scope than the whole procedure can be more easily performed using that instead of the scope itself. These first 4 steps are to make you are coarsely aligned with the NP as well as to make sure you have enough latitude of adjustment in the azimuth controls for the real job of PA the mount. ---------------------------------------------------------- Now to the actual procedure itself: 5. Move the telescope manually so that point at a bright star near the meridian within 10 degrees of the celestial equator. Make sure the mount isn't tracking. Mount the camera (let's assume a DSLR) so that the long axis of the camera is either at 90 degrees to the optical axis of the scope or parallel to it. Or just place a mid-power EP in the EP holder 6. Establish which side is North and which is south by nudging the scope up and down, either in the EP (easier) or by looking at the live view screen in the DSLR or by hooking the camera to a a PC with APT installed or any other software capable to display the live view from the camera. 7. Once established which way is North (or South) you can turn on the tracking and see which way the star goes. It can either be toward North or South. If it is toward the North then shift the mount using the azimuth controls toward the East, vice versa if it drifts towards to South. Once there is no significant movement either way go to the next step. 8. Now shift the mount so it points to a star 6 hours before crossing the meridian (i.e, East). If the star drift toward the North then you need to lower the polar axis (of the mount, using the altitude screw) and the opposite if it veers toward the South. You can do the same thing if instead of the East you point West (6 hours after crossing the meridian) just invert the terms North with South in the adjustments above. 9. Go back to the meridian and repeat step 7 until there is no discernible drift either South or North (East to West is irrelevant here) for around 1 min and you have nailed your PA. |
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andrea tasselli: Thank you so much you helped me with all my questions! <3 |
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| Guys, I'm using the canon eos 600d with a pixel size of 4.29 with my telescope with a focal length of 1000, these two are not bad. If I take the svbony 60mm f4 guide scope and the svbony sv205 camera with pixel size of 1.4, how will the compatibility be? At astronomy.tools "The imaging / guiding ratio is 1:1.36." says. is it good? |
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| I'd say up to a 1:3 ratio you're golden. |
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andrea tasselli: Very nice.1:1 would be great to get. then i will go with these equipments |
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| I made a timelapse from 14 minutes of data, maybe it will help you get an idea. each photo is 30 seconds M13.mp4 |
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| Guys, is it normal for it to move a little even though I locked the dec clutch knob? It's pretty obvious when you're observing. |
