FaDG

As a minimum, for some serious results, you'll also need a guide camera + guide scope or OffAxis guider. Not to mention a laptop or ASIAir or similar and maybe light pollution filters depending on your location

Small RA backlash shouldn't be an issue because when imaging/guiding this axis does never revert its motion (unless guide speed >1x, which I have never seen). So, unless it leads to inaccurate gotos, you could well live with it.

One final word: your first two calibration figures and drive rates seem fine to me: I have seen mounts guiding seamlessly with results much worse than those. You may try to increase the guiding rate to 1x to increase mechanical reactiveness and reduce PHD2 aggressiveness in RA. this should tame the Dec backlash a bit, reducing the 58" to below 30. Buth this value is out of spec anyway: if confirmed you could contact the dealer asking them to optimised the worm gear block positioning. It's by no means indicating that the mount is faulty, just low care in assembly and quality check. But hey, you didn't purchase a 10 micron, did you? Manufacturers in china sadly don't waste too much time on QA. As for the different direction: did you perform a meridian flip between the two calibration runs? Keep up

If the OP mount has 15 arcsec of PE I would NEVER return it and rather have the backlash sorted out. It's an uncommonly good value for that class of mount: my HEQ5 has 23arcsec peak to peak and I'm just delighted with it Yet I suspect that Guiding Assistant was only exercised on part of the worm and the real PE will be higher, usually in the range of 80-100 arcsec for an EQ3. Yet it should be able to drive happily even with that, so the main issue seems to me the massive dec backlash.

Hi Miguel, my experience is that setting up autoguiding parameters opens up a totally different can of worms. Hence I'd suggest that you try to assess the quality of your mount BEFORE you try to guide by: Taking some unguided shots, measuring the backlash and the Periodic Error, testing the accuracy of the gotos and feeling by hand any roughness in the axes motion. Once you're aware of the mechanics, you can safely set up the guide system, but also in this case, I advise my friends to start with RA only, as this isn't impacted by backlash. Dec is always more tricky and if you have moderate backlash you can try the procedure above to avoid it. Yet, having already homed in the parameters with RA guiding, it should be easier. Try to avoid massive overcorrections in both axes, and good luck.

Very long post which deserves a very long reply... Well, let's start from the gear: you're using an entry level mount to drive an APO with a high level CCD. Maybe you chose to save on the wrong end, but this being said, let's look at the graph and settings. You have serious obershooting in RA, due to an estremely high aggressiveness. Try lowering RA aggressiveness to 40-50 until corrections end up close to zero, slight undercorrections should be preferred. I don't see this to be the mount's fault Now to dec: 58" backlash is enormous. It can usually be adjusted out easily (at least on non goto mounts), but I understand that it shouldn't happen on a new mount. You'll never get zero dec backlash but 58" (if the GA is right) is unmanageable. Try moving it North and South with the controller at a low speed: does it really take souch time before moving in the opposite direction? Did you select 0,5x or 1x as guiding speed? Two points here: Synscan has a settings to correct backlash, it could be used for smaller amounts. And, actually when guiding dec backlash can be ignored, you just need to do the following: BEFORE calibration, move the mount North with the controller until all backlash is absorbed. Then perform calibration as usual. Ignore any complaint about insufficient South movement. Now leave PHD on its own for about one minute and assess direction of dec drift, and force dec corrections only in that direction. If drift is southward, move manually with controller until drift is absorbed again. From now on it should just be fine. I am a bit surprised that you tested the mount with guiding on your first outing, this makes hard to separate mount connected issues from those coming from the guiding. I'd make a Periodic Error measurement, because you could send back a perfectly working mount which just needs a bit of fine tuning. You could contact your dealer, but the question is: if you return it, is it worth to replace it with another EQ 3, or rather upgrade at least to an EQ5? I agree with previous comment: an HEQ5 is the solution I'd suggest (if your budget can stretch to that point) Good luck, Fabio

You're right, I remember having seen a belt driven CG5 ASGT but it had been belt modded, probably. My mount did not have goto, so it was like the OP one. Upgrade to the HEQ5 has proven invaluable.

Hi Dan, the LXD is basically the same head as the EQ5 and the CG5, the difference being the Autostar goto (and if I'm not astray, belt drive like the CG5 GT instead of cogs like the EQ5). So, apart from the goto, no big improvement vs. the EQ5. The HEQ5, now this is playing in a completely different class. You're not changing for that to increase the payload (or only in a minimal part). You do so for the accuracy and consistency of the results. I passed from an EQ5 to a belt modded HEQ5 and my only regret was the time I spent before changing, which would yielded many hours worth of fine data! I use it guided with a 150p Newt or either an ED80 or a 72ED and it is consistently tracking with less than 0,6 arcsec RMS error on nights of good seeing. Look at it as a scaled down EQ6, not a beefed up EQ5. The best money I spent for the hobby.

Luckily, I can confirm a significant improvement shooting from the centre of Rome, mostly due to reduced street traffic, IMO. The air just smells cleaner too. This is a WIDEBAND (IDAS D1) shot of M81 and M82 from my place: nothing to write home about (well, also bacause I'm already at home! 🤣), but this wasn't possible before COVID19 outbreak. Been there, seen that.

It depends on your SA accuracy (mainly the amount of Periodic Error), how good your Polar Alignment is and your tolerance to one or two pixel trailing. A friend of mine uses three minutes subs with his Samyang 135 and Star Adventurer which is, I think, a very good sample. Stay health, Fabio

Well, this is very stringent: I use this configuration on my HEQ5 and I definitely don't recalibrate for each change of target, but only on meridian flips. Actually, using ST4 only, I have found out that, when imaging at high dec, better results are achieved by calibrating on stars at lower dec and then slewing to target. This is due to the lower RA motion for each step at high dec.

Or after a meridian flip.. 🤔 It seems that the corrections are actually increasing the error, that is compensating in the oppostite direction. Did you calibrate on one side of the Pier and then guide on the other side using ST4 on camera?

Definitely support the Samyang, lots of fantastic shots with that lens on the net, but you'll need to shop used to stay in the 200 mark. Yet, I am more skeptical on the nifty fifty (50 f1.8): wide open i find it really soft, and even stopped down to f5.6 it still shows a lot of field curvature and vignetting. Somehow I never managed to get a really satisfying shot with it. You could also consider old M42 lenses: there is a lot of very good ones spelling for cheap. I find Jupiter ones to be great, with just the minor issue of being radioactive due to the torium back element... But my nose hasn't turned green yet, and it could be handy if glowing in the dark! Well, enough kidding: my Jupiter 135 f3.5 is definitely a great lens.

Just went through this thread and noticed that, despite the 9 pages of great equipment, something is missing. So here my small contribution. That's my Polarie sitting on the Star Adventurer wedge on an ancient EQ1 wooden tripod, carrying a Canon 600d and a Sigma 105 f2.8. A great tracker, not my only one but the best and beloved! No guiding capability, but that's exactly the right concept to travel light, and with its 15 arcsec peak to peak it manages three minutes subs without issues. The polarscope is super, but the only design limit is that it can't stay in place with the default mount for the ball head. So I 3d printed an adapter to keep it in place and use the Star Adventurer counterweight. So, kinda Frankenmount, but I'm in love with it. Fabio

Mmmh, did I mention I'm shooting from the heart of Rome? Not exactly the darkest sky!! Furthermore, 320mm focal length is too short for planetaries But yes, I'll post the result. I'd be really happy for it to look like your logo!

Right. I'm shooting M97, as far as it gets from the moon.

Hi Alan, welcome aboard. I suspect it could have been a batch of Starlink satellites, although two minutes between them seems too much. Yet they may have spread in True Anomaly along the orbit since I saw them last time. There are online trackers, where you insert location and date ti check for visibility.

I use a 150pds with a Canon 600 or 650 on a belt modded HEQ5. The comacorr brings the focal length down to 690mm, and the mount does not have the least problem in guiding well below 1arcsec RMS, with basically no lost frames, at an imaging resolution of 1.28 arcsec/pixel. No issue at all with load (150pds + DSLR +60mm guide scope + ASI120) or balancing. I agree with the statement above that a 200mm newton would exceed the mount photo capabilities. Fabio

Hi Peter, thanks for sharing the result! may I ask you why you prefer the D2 image? In this narrow vs. Moderately wideband comparison, the signal seems comparable, but the Sky background is darker in the Optolong one, so you're not taking advantage of the NB ability ti increase the exposure time. A comparison with similar background levels would also be interesting.

Skywatcher 72ED + flattener/reducer + dew strip should be around your target point

A few mixed answer to specific points in previous posts: Yes, definitely. Life is too short to lose frames due to trailing. I wouldn't run my 72ED @ 320mm unguided, let alone the 150/750! And by no means a 200! Feel free to try, but be informed that I bought my HEQ5 second hand from a guy that wasn't satisfied of its performance with a 200p. For me it's just magical with my 150. Additionally to the collimator mentioned above, you'll find a coma corrector quite a must. Warning if going the OAG route. Most newtons don't have enough backfocus for that. My 150p not for sure, more so with the comacorr. And, depending on where you live, filters might be in order. I image from the centre of Rome, so narrowband is the only way

IMO, the 200 is a bit the limit for the HEQ5. I use a 150p on mine and it's a great setup. But I concur that a reflector is slighly more complex to master than a refractor. Yet, I also have a Skywatcher ED80 I used as a first imaging scope, and there is really no comparison between the two! The frac doesn't get much use, nowadays. All the best, Fabio

Yes, that's better, IMO. You could keep one of you previous lights as reference so that next time you can point the camera with the same orientation and add more integration time. Then, if you use your UHC to cut through light pollution, the new image with more contrast could become your luminance layer, and the previous one (with unfiltered colour) be superimposed as RGB after coregistration. In this way you could benefit from higher contrast and SNR, AND keep natural looking colours.

Nice shot, Vintage lenses offer a great value! You could add more lights on different nights and a modded camera will give you a lot more signal. Here is the same target acquired with a different vintage lens, but same focal length : Jupiter 135 f3.5 (the radioactive one, I fancy it could produce an image even when left in a closet! 🤣) on a modded Canon 600d. For this shot I have added a 2" IDAS V4 in front of the lens, to keep light pollution at bay.

A lot of data in there for the short integrato time! What is the used setup and where did you shoot from?