jambouk

Not strictly astronomical, but the Nottingham Astronomical Society will have a stand at the forthcoming Geological Survey Open Day; see attached flyer. I've been to the BGS open day before and it is very good, amazing to see their rock collections and get a tour of their labs and storage facilities, and usually some interesting talks. James A4 openday poster_2015_v2.pdf

A friend was asking me why there was no setting circle on the azimuth axis of this mount; I have no idea, but it would be helpful if one doesn't know the sky as it could be used to help with star alignment. Anyway, I found this really useful link on the net: https://kenallen1976.wordpress.com/tag/alt-az-telescope-azimuth-ring-home-made-skywatcher/ James

Levelling the tripod is one of the main pre-requisits for the Skywatcher Mount; it does mention this in the set up instructions (http://www.skywatcher.com/downloads/AZ80&114.pdf). With regards starting from the "index point", this is something which isn't mentioned in the Skywatcher manual, but there appears to be some differences between Skywatcher and Celestron. The star alignment options in this Skywatcher mount are: Brightest star (one star) or two star alignment. The user has to slew the scope manually to the first star always, so in effect it makes no difference to the mount what the original starting point is. However, as part of my routine when I was using this mount, I used to start at the "index point" as I believed it made my whole alignment more accurate, though I never did any tests to check this. Equally, with the Skywatcher kit, there is no option to centre the star in the finderscope first, then press enter, then centre in the main scope... The user is asked to centre the star and press enter once. I recommend to people centring the star with a low magnification eye piece first, then swap over to a higher magnification eyepiece and re-centre, and possible then put the high mag eye piece in a barlow and re-centre THEN press enter. Again, always ending the centring with an up and right key stroke. James

It does take some time to refine the position, but not 60 seconds. Maybe collect some data on this, say measure the total time it takes to slew using GOTO from Deneb to Vega, repeat the test 10 times and see if it consistently takes the same length of time; then repeat for two stars further apart in bother RA and Dec, say Vega and Spica, and Vega and Castor. See if one axis is likely causing the problem. It may be that it just seems slow, but is normal. But without knowing the time it takes, it is difficult to comment on if this is abnormal; I can test it against my Skywatcher version once you have the data. Again, it is undertaking a reasonably precise movement, and I am not an engineer, but for a £150 mount to be able to GOTO an object amongst a 42000 item database with an accuracy of under 30arcminutes and to be able to track it at sidereal rate... I think that is quite impressive, even if it does take 30 seconds to decide exactly where it thinks the object should be. Get back to us with some data - maybe start a new thread as this is a bit off topic now. James

Half a degree is reasonable, but I've had it tighter. This mount is the most basic of GOTO mounts out there, and is relatively "cheap" so one is unlikely to be getting bang on GOTO accuracy; even with an HEQ5 or NEQ6 equatorial mounts people can be happy with half a degree accuracy. The GOTO accuracy depends on just SOOOOO many things. All of which much be summarised in this thread - be worth taking the time to read the whole thread. Is there much slop in either axis? If so, tighten the nuts (I'm sure discussed earlier in the thread). Level the tripod before attaching the mount head. Can you add stability to the tripod? Ensure power supply is sound and constant. Is the scope balanced as well as possible. Try centring your alignment stars with the reticle eyepiece, then if you have one put a barlow on the reticle and centre again before accepting (effectivly turing the 20mm EP into a 10mm EP with a 2x Barlow); if you had a 12mm reticle EP I'd still add the Barlow and centre with effectively a 6mm EP. Always end your mount adjustments using just the up and right arrows. Do a two star alignment rather than one / brightest star. Do not touch the tripod once the start alignment process has started or finished... There will be other things people advise, but I think these are the most important. In my opinion, a GPS device is unnecessary as it is pretty easy to input the date and time (and doesn't matter greatly if these are out by an hour or so, or a day or so (the commonest error is to forget to enter the date in the American format)), and the precise latitude and longitude is equally unimportant (being up to a couple of degrees out in latitude or longitude makes little difference). Keep at it, it will get easier and your accuracy will get better, but I think half a degree out is acceptible. If the object is likely to be out of the FoV with the 12mm EP, then I would use a lower power EP first when you've GOTO'd, re-cente, then swap for the higher mag EP, and use the PAE function to update the GOTO for that constellation. Good luck. James

Hopefully attached to this is a file which shows the menu tree on the Handset when using v3.37 of the firmware with the Alt-Az GOTO mount; I'm not sure why some of the options are listed when they cannot be used, or how some of the other options are useful. The menu tree listed in the official Skywatcher manual for this mount is now out of date and wrong and I've made this list for a friend. James v3-AZGOTO.doc

The best way I know of quantifying it was described somewhere here on SGL. I can't find the thread, but someone else might be able to. Essentially: - slew the scope in just RA or Dec (do one at a time, though some will argue the backlash in Dec is less [un]important - with a high power EP or reticle EP (or cam connected to computer with reticle on screen) slew on slow rate (say rate 1 or 2) so the cross hairs just go over something very distant on the horizon which isn't going to move, only do this manoever using one direction key (say the right arrow key), so if you over shoot, go much further the other way back (using the left arrow key say) and then go again to the target slowly (with the right arrow key) - [make sure tracking is off before you start] - then make sure you are on a very slow rate, say rate 1 - note down where the hand set thinks the scope is pointing in both RA and Dec - now use the opposite arrow key (left arrow key in this example) at rate 1 to slew in the other direction - you may hear the mount mechanism moving, but the image won't move for a bit - keep going - as soon as you see ANY movement stop pressing the arrow key - now note down where the handset thinks it is now pointing - the time it took from you first pressing the arrow key to when the scope first moved is the backlash in that axis - you can roughly calculate the backlash in that axis by subtracting the first set of co-ordinates from the last set of co-ordinates - you may want to repeat this a few times and take the average of a set of 3 or 5 observations - then repeat as above for the other axis Hey presto, you have a rough idea of how much backlash there is in your mount. Make sure it is all well balance first. Knowing this information can be useful if you subsequently make adjustments in the mount, to see if you have improved the backlash or not. I've always been dubious about actually inputting the amount of backlash into the handset for it to make auto corrections, as I worry it would make the corrections all the time, even when at times the "cogs" may already be meshed together and so it applies a backlash compensation when it isn't needed so over compensated. If there was a feedback mechanism in the system for it to know if there was sufficient tension on the cogs then it would make sense, but I don't think it is that clever. By following the astrobaby EQ6 page you can physically reduce the backlash on the AZEQ6, but it takes some time, and it is a balance between getting the backlash reduced, and not getting things too tight so they catch at some part of a full rotation around either axis. For GOTO accuracy, I found that correcting my cone error made a MUCH bigger improvement than reducing my backlash. JD

What's that?

Out of interest I took my little aluminium-like cover off (some electronics under it) but it wasn't scored at all by the mount unlike in the one in the pictures above. James

You two are going to have people knocking on your doors asking for a clean and tune up!

If you live anywhere near Nottingham i'd happily take the pictures for you.

Maybe start a new thread asking azeq6 owners. There might only be two or three people who would be interested in which case it would be a lot of work for you with little return. You'd need to include photos and labels for absolutely everything and maybe show the tools you used at each stage too, so thickos like me could follow it i'd be happy to help proof read it for you for free and see if i could follow the guide. If you were going to sell it, maybe check with someone clever that it wouldn't breach any form of copyright (which i doubt it would). James

Are you asking me opinion or asking for other people on the thread? I think you'd get a fair amount of interest - it's becoming a reasonably popular mount, and is sufficiently different from the NEQ6 that guides about that are not all inclusive, and you know what astro people are like for tinkering, stripping, cleaning, tuning, re-greasing... And with summer approaching... It would need to be good as i think word of mouth or word of forum would spread. James

Will there be a pictorial guide eventually of how to take an AZEQ6 apart and how to reassemble? I think if you only made it available on paper and made sure the PDF files didn't get into circulation, people would buy it for £10 or so. James

The lower puck just has a threaded central hole through which the mounts existing bolt screws. The top puck (on mine anyway) has a bolt already in situ which is not removable from memory; no idea of length. Mine is currently all set up so i can't measure it for you. Astroboot sell a load of random bits, ask them. James

Does the top puck have a central bolt to screw into the base of your mount? If so, i think that is everything. A puck top and bottom, the tube, and a central bolt at the top to screw into the mount. James

How big is the avi in question? Have you tried opening an avi file which you know it has previously opened?

Blimey. Thanks for that. That is an uber useful guide. Looking forward to following it if i ever get imaging the sun. Thanks for taking the time to pit it together. James

No, appling the BOA to the hand screw underneath which sits between the tripod legs. I can't see how putting it around the extension tube would help... Clearly i've got the wrong end of the stick [bOA] James

I think i'm overly worrying, as the rotation is only apparent if i apply a fair anount of lateral rotating force, not something i normally do when set up. Thanks all James

I had realised that either, until you said. I can't get them to work as there is no room to rotate them as the tripod legs get in the way. Handy for the tool bag anyway Jd

Got the tool, now to see if it works

No, the bearing is the top of the extension tube, the rotation is at the bottom. I did have the bearings off centre initially but thought it looked wrong so did centre it. James

I'll wait and try the wrench. Looking at the two surfaces, i think the point of contact is the outer rin of the extension tube (a couple of mm thick) which is painted white, on to the white paint surface at the top of the tripod, so is one slippy surface on another. The central puck inside the extension tube doesn't seem to sit on the tripod, it is sunken into the tube by a mm or so other than the nose piece which slits into the sunken hole in the centre of the tripod. I'll experiment with various materials between the two slippy surfaces. James

Ordered a BOA wrench; never heard of one before. I'm slightly scared that something will break if i tighten too much. It wouldn't be the first time i've snapped a skywatcher bolt! I'll experiment with the fine sand paper today. I still feel a large thin rubber washer would do the trick. James