| You're experience with the ASI2600MCPRO DUO guiding has been: | |
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| Awesome, Im ditching my guide scope | |
| Better than expected but, I'm keeping my classic OAG/guidescope setup on the rig | |
| Worse than expected, unreliable | |
| Returned/sold it already | |
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Ive utilized the DUO with the SHarpstar 61 EDPH II and the RC8 , both at native and .67 reduced focal lengths. I have a Hyperstar C8 but haven't used the Duo on it yet. and I am using the AM5 with the ASIair plus. My impression is that the wonky star shapes don't pose a large problem at short FL, although my guiding numbers are significantly worse than utilizing a 50mm guide scope and 290MM mini, the images at short FL don't seem to suffer because the arcsec/pp is larger than the RMS error. But once that dynamic changes obviously it's a waste of time. I have spent several nights trying to tame the guiding specifically the RA, to no avail. I have adjusted the Max pulse from 1-10k and stepped through every aggression percentage, at .2 to 5sec guide exposures in Bin 1 and 2 with the dark library and without. There was no difference in the RA and overall guiding at any configuration. Generally the RMS at 1000-1600FL is .7-3+. with the bulk of time spent in the 1.5+ area. The time it dips below 1 is short-lived, like 20 seconds or so. And so I've come to believe, correct me if there is something I have adjusted or considered, is that the wonky star shape has dispersed centroids which causes the the guiding to chase the movement of 3~ centroids that each vary in intensity per frame. So depending on which centroid it is utilizing the RMS swing can suffer. |
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Hi Brian I can't speak to the DUO, but I have some experience in off-axis guiding with an GSO RC8. Like you I used to struggle to get below 1arsec without a flattended field. Like the off-axis guiding, the DUO guides on stars a long-way off-axis. For the curved field of an RC this appears to be problematic. [And a reducer will only exacerbate this problem]. I am not sure why this should be the case, but once I acquired a field-flattener for my RC the rms guiding reduced dramatically to 0.5arcsec rms. [As good as I am likely to get in my 4-5arcsec seeing]. To be honest, I hadn't given the cause of the initially poor tracking much further thought until your message, which reminded me of my initial woes. My issue with some retailers of RCs is that they can be marketed as having a "corrected field" ideal for AP. . This is nonsense, as all RCs have curved focal planes. For AP, selling an RC without a field flattener is akin to selling a Newtonian without a coma corrector. I am not sure whether the purchase of a field flattener will improve your guiding, but it should improve your images. Unfortunately I could find no combined reducer/flattener for an RC8. CS Brian |
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| Thanks for that knowledge Brian. I do not have a field flattener (yet). |
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Hi, thank you @Brian Boyle for your comment. I was looking with some interest on @Brian s question, because I had trouble with my OAG on the RC8 as well. Compared to a guide scope, my quiding was really bad with my OAG. I tried some time to get it working, but I never got something nearly as good as with my guide scopes. So at one point I gave up and put my guide scope back on which works okayish for me. Maybe I should try another scope with the OAG, which is lying around for some time now. Using the RC8 at its native focal length might be too much for my EQ6R mount and my cameras. So I need to work with the 0.67x reducer. So a flattener might be problematic with this. Maybe, there are some other users of RC8s out there, who can help with their experiences with OAG. I'd love to hear their stories. CS Christian |
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Here's my Player One OAG, ASI174mm on a Celestron Edge HD8 and Skywatcher EQ6-R pro. |
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How is your seeing? FWIW, I have a C9.25 Edge at FL 2350mm (no reducer--had star problems with it), & OAG and for me, seeing and guiding pretty much go hand in hand. I experience a wide range of seeing conditions, though never great, and if (rarely) seeing is in the 2.5" fwhm range (or about 4.5px HFR as reported in Nina), then my guiding will be around .5" total RMS, but at around 4 - 5" fwhm seeing, my guiding exceeds 1". I've tried to improve guiding in poor seeing conditions quite a lot, but usually no success. There was one time, though, where switching exposure from 3" to 1", aggressiveness from 75% to 50%, and hysteresis from 20% to 5% (all somewhat randomly chosen) made a very significant difference, and continued working well through a variety of seeing conditions......until it didn't. And now I'm back to the original settings. Cheers, Scott |
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Great. See my post in the other thread https://www.astrobin.com/forum/c/equipment-forums/zwo-asi2600mc-duo/using-a-zwo-2600mc-duo-with-a-long-focal-length-scope/ |
