Bill Dirks:
Thanks.
I didn't note the guide settings, but it was certainly 2s, and also I probably used bin2 on the guide camera. There are obviously fewer and dimmer guide stars with higher focal lengths, but I didn't have an issues on those images. Lucky. I probably pointed a little off center of the targets to get more favorable guide star position.
I almost always use 2s with the EdgeHD 925. I don't see an improvement with 1s, and with 0.5s I get a bad oscillation. That might be fixable with other guide settings, but I don't know enough about it. This is with a 14 to 15 kg payload, and a 4.5 kg counterweight on the AM5, close it its limit. I think at 0.5s it can't respond fast enough against that much angular momentum. Longer guide exposure also averages out the seeing better. On other projects I have used 3s and even 4s when shooting with a Duo camera through color filters and the guide stars are dim. It still guides well enough. With a large payload the angular momentum is helping you, so don't fight it? I admit to being a noob here.
Hi Bill/Daniel.
Bill, it's great to hear the AM5 is performing well with a counterweight and near its weight limit at a long focal length. I'm a keen ZWO user (of multiple Asiairs, various cameras and a little Seestar S50 smartscope, but not an AM mount - yet, and have been a loyal customer of theirs almost since they began, with one of Sam Wen's first planetary cameras). Guiding with my 10Micron mount, mostly using an Asiair PLUS, is almost the opposite to your AM5 (I seldom guide with it though as I mostly image unguided, unless I need to but can't be bothered building a new sky model for the mount - about a 15-25 minute process of waiting while it gets 50 to 99 sky images all over the sky and plate solves them all to build a full-sky model). With the 10Micron's high precision dual encoders and engineering giving virtually zero PE/backlash or other mechanical errors, very long or at least widely spaced guide intervals are usually recommended and tend to work best, maybe 10 seconds or even longer, just a handful of guide intervals per minute to let the encoders/high precision tracking, the mount's comprehensive sky model, and it's air temp/pressure sensor based atmospheric refraction compensation do most of the work, with just some occasional guiding assistance. They are very different ways to try and achieve round stars and good sharpness between those opposite ends of mount PE levels between an AM or other strainwave mount and an encoder equipped AP/10Micron/ASA/Planewave etc mount, but both ways can certainly work nicely even at longish focal lengths, and at hugely different cost levels.
Daniel, the 10Micron certainly is extremely nice, wonderfully engineered and with some very clever firmware, and does suit long focal lengths very well, but with careful guiding people produce amazing sharp images at quite long focal lengths with ZWO AMs, Sky watcher/Celestron and many other not quite as precise mounts as well, and the whopping cost of a 10Micron mount is always going to seriously limit the numbers of them, as is the case with AP/Planewave/ASA and other very high precision dual-axis encoder mount brands. I came mostly from the Celestron mount world before my 10Micron and was a primary beta tester for Celestron, and I still successfully use an old Celestron mount I keep at another location, and really like and regularly still use my tiny and very sloppy but clever Skywatcher Heliofind specialised solar tracking mount, and my tabletop Skywatcher Heritage 130p mini-dobsonian). Interestingly, one thing that happens with a 10Micron mount, for me anyway, is that you very soon come to hardly even notice it. Because it performs so faultlessly and precisely it usually just isn't a factor you have to think/worry about at all during an imaging session, so it drops out of your thoughts, which sometimes can feel a tiny bit anti-climactic given the money spent on it. It's a strange phenomenon. Mine gets a lot more cobwebs etc on it in my backyard dome than my old Celestron mounts did, because with those I was always having to fiddle around with them and look at them to do things, but the 10Micron can sit there for many months hardly even being looked at, just switched on around dusk, used faultlessly for each session, then parked and turned off before bed or the next morning, which means it tends to sit there unnoticed gathering dust and cobwebs etc until I suddenly notice that it is all dirty and needs a good wipe down/clean with a small amount of petroleum jelly (10Micron's recommended treatment for the exterior of the mount).
I also really enjoy the opposite of what we are talking about in this group, short focal length/very fast f-ratio/short imaging time sessions, and often image with my C11 Edge HD with a Starizona Hyperstar lens at f/2 and only 560mm focal length ... but that is well off-topic here.
Cheers,
Chris
