sophiecentaur

My Astronomical Society has a burgeoning Young Astronomers group and we are considering buying some appropriate equipment for them. We already have some low cost binoculars (the obvious first choice) and we have some cash to move up a step. The requirements for kids are not the same as for adult beginners so it would be good to hear opinions from SGL who have made good (and bad) purchases for younger members. I'd always recommend a Dobsonian for an adult starter, simply because you get so much bang per buck and the value for money is obvious, once you have your first look at, say the Pliades through a 150mm reflector. But a Dob is hard to drive and needs concentration and the control to keep it where you want it to be. The table-top Dobsonians have advantages but, where we would be observing, there are no firm tables. What do you think?

I was going through all the available options for me - that are cheap or free. I then realised that, with Apple, you have Screen Share which is universal and free!!!! So I have already managed to use my nice big screen iMac to control the macBook. And again, I have an elderly Mac mini (2011), which would fit right on the mount. The only question is whether its usb2 ports on the mini are quick enough. But there is another possibility in the form of an Apple Thunderbolt outlet on the mini which, they say, give fast connectivity to a range of (fast USB) peripherals. It may be worth getting hold of an adaptor and just trying that out. It would be a cool solution, requiring only a memory upgrade for the mini. 8GB should do it for less than £30. Having been moaning about using Windows and the far from friendly ZWO ASIstudio etc. it was such a nice experience just to 'enable screen sharing' on a Mac and to connect the other Mac via the normal Network display. There was the other screen, visible and everything worked as if I was using the remote machine. An yet people 'hate Macs'. I can agree that a developer can get on far easier with a PC but it's 'users' who object to Apple. It's big endians and little endians all over again. (See Gulliver's travels)

I get the feeling that ZWO software is a bit 'bare minimum' in its design. It works on the test machines / platforms they happen to have but not necessarily on 'yours'. The AVI files that ASIcap outputs on my computer are not read by VLC (a pretty standard bit of software) and I have to pass them through PRISM before I can look at them. Where are all the options in the Preferences? Their USB interface software also seems to assume that the user can drive it appropriately to get a continuous flow of frames. You would think that ZWO software would talk properly to ZWO hardware without the user needing to muddle through. I can't find a button to let me choose the format of output movies without dropouts and freezing. Perhaps the different divisions of ZWO are not well integrated. I have heard that it's the same with SONY. I think Astrophtographers are too soft with suppliers.

That's not a bad idea and I could use team viewer to control it (from the cosy conservatory). There seems to be no easy way to do astrphotograpy. Doing it electronically needs (a minimum of) four separate data connections needed for mount, images, filter and focus plus my system could need to use two (or at least one and a half) computers, connected by wifi or some cable arrangement. Then there are the other basic problems that all telescopes encounter and, in an automatic system, you could go away and come back in a couple of hours and find that you got only 30s worth of usable data. All that's fine if you have 'professional' resources and budget but, on a shoe string -- yoy yoy yoy. "The maximum data transfer rate for USB3 is much faster than can be achieved using Wi-Fi or even wired ethernet. USB3 is 5Gb/s while gigabit ethernet is 1Gb/s. Also true. USB is only fast when you are using devices that are almost as close to the computer as the internal ones! Data transfer speeds is a subject like HiFi, that has more promise than delivery.

I was having some problems with my ZWO ASI290MC connection to my MacBook Pro and suspected a cable fault. So that was why I contacted ZWO and asked about how I should actually be connecting my kit to the computer. I wanted some helpful advice about a reliable adaptor to connect my ZWO usb3 B to the Thunderbolt sockets. Also, how to connect to somewhere warm, indoors. They recommended using their own ASIAIR wifi system, having told me that they would not recommend more than 2m of cable link. (That's pretty impractical for most people, without an Obbo.) I'm sure they could do better than that, with appropriate data coding, despite their HD imaging requirement. I don't know about experiences of other members but home wifi can be very problematical. I really don't want to invest in a wifi hub for the garden if I can't be sure that it will actually do the job. I have two options for a control base. One is the nearby shed which should need a bit over 3m of cable and the conservatory, which is more like 10m away but would be much more cosy and comfy. A 10m USB cable (or perhaps more than one) would be ideal but the probable performance would be predictably poor - wifi would be an unknown quantity. (USB repeater?) I would love to know what other members use for longish connections. Images and movies can present high data rate demands.

That seems to be what I'm getting, I think.

I get this effect with Stellarium but also if I press home on the EQMOD control panel. For normal slewing (i.e. when adjusting the scope before syncing) you can choose four speeds from snail pace to noisily fast. I'm just wondering how good Ascom and EQMOD really are. The package claims to be all singing all dancing and I haven't heard anyone actually complain- and let's face it, it's stood the test of time and gets frequent updates so it's still 'loved' by its developers. I have a complaint that the fold-out control panel is a bit confusing and you definitely have to learn the right approach. The official YouTube videos I've looked at present it in a convincing way but my brain works differently. I've only used Stellarium in anger but CdC doesn't make the speeds any more sensible. I'm sure it's possible to get inside Ascom if you're savvy enough. It's all open source and has loads of documentation for capable developers.

Most people who have discarded their SynScan handset in favour of a direct connection seem to swear by it. They say it's more 'reliable' and I accept their experience. BUT there is a strange feature of the way the handset seems actually to control what happens to the mount during slewing. Send the mount to a target, selected on the SynScan handset menu and the mount goes there relatively quietly and by a 'direct route'. When it arrives, the slew speed drops once, then again , after a short period of jiggling around, and there's no fuss. Using an ASCOM Driver through Eqmod, the route on both my mounts (NEQ6 Pro and EQ3 Pro) take it a very strange route - always involving a Meridian Flip, apparently, right up to NCP and out again and then, when it arrives at the target there is a lot of to-ing and fro-ing 'at high speed' before dropping speed and eventually settling down. Does this happen to everyone who does it this way? The procedure sounds so alarming that I'm sure there must be some way of controlling such wild behaviour. I know that ASCOM is a very useful package but is it too generic to take care of things like that? And, talking of alarming sounds, that EQ3 Pro sounds particularly dreadful and, try as I may with adjusting the motor mounts to improve the meshing, those poor little brass coloured gears really seem to be having trouble. They are not worn out as the mount has only been used in anger a very few times. People on forums have very strong opinions about lubrication but I seriously wonder whether I should get some of the very thickest grease and try to sort the problem that way.

Progress so far. Motors removed and worms / wheels are checked clear of garbage. Replaced with minimal backlash. Both pairs of windings are metered with the same resistance value (about 6.5 Ohms) so my problem was most probably the control board itself. I am really not that impressed with the worm alignment system two pairs of screws, working at right angles and a single grub screw to work, along with tilting between two of the mounting screws. Smacks a bit of the awful Az adjustment in the mount base of my NEQ6 and the inadequate floating dovetail clamping system. But what can you expect when things are 'competitively priced'? I can't blame Ascom for giving strange signals to the driver board - nor Stellarium. New box ordered and arriving soon!!!

Hi Julian Thanks for the reply. 1. With clutches released the two axes are probably just about right; A hint of friction and no slop. 2. I don't have the manual knobs and the 1/4" shafts are too small. But the covers are off and the gears are relatively easy to move with fingers (fingers slightly chewed up after 2X360degrees). I was wondering if something is hanging around in there and occasionally catching. That will need disassembly but I will put that off if and until it does that stopping behaviour again when the current mending is achieved. Obvs Stellarium the oappears getting some feedback so that. in spite of halting, it picks up again and puts the scope icon in the right final place. I don't know if a stepper driver can record success and failure of each pulse. 3. I can't drive the motors 'cos the control box is bust. As for details of the electrics, I think I'll have to follow up on some of the posts by cognoscenti who have done their own motorising. The correct motors are available but I haven.t found any fine details about the EQ system. SW say that they are common between EQ3,5 and 6 (which is good news).

After some period of inactivity, I have started truing to use my EQ3 Pro, direct via the USB / Serial cable and using Stellarium to steer it. I noticed that sometimes the scope would stop half way through a slew and then, when Control 1 was pressed again, it could continue its journey and get to the right place on the Stellarium display. (All done indoors so I can't be sure about where the mount was actually pointing). I left it connected for some while with tracking off and smelled a hot electronics smell. The motor control box was very hot and the heat had actually softened the plastic. I found a replacement box and have ordered it but how can I be sure that the problem isn't with the motors? I don't need a further £100+ wasted on a second replacement box. If I had pinout information for the motors, I could at least detect a short circuit. Both motors seem to be working against the same sort of mechanical resistance when I turn the gears with my fingers. I have not explored the whole range of RA dnd Dec angles but that would probably be the next thing to try; there could be a tight spot on one worm. I guess it would involve more disassembly. I am short of test equipment but I do have access to an elderly analog scope. Is there a source of more information of the SW kit, other than user guides? Any ideas chaps? Cheers

Hi @Rusted That's an interesting link and the arrangement for focussing, using the prism is what I suspected but I was assuming a normal 45 degree prism . I think something must be mis-aligned to cause that sideways drift. I contacted Meade and they offer a $150 repair (for virtually anything including replacement) plus $20 carriage (@Mexico !!) but that may not apply to UK, which is where I am located. I shall have to approach the vendor when I have more info from Meade. We may need to modify the price on the basis of spares or repair, if he wants to. I enjoy a challenge; if that filter has actually burned out, it would make the scope not very interesting but the mis-aligned focuser could be solved, I'm sure. [Edit: I will take off the side plate and see if I can re-align the prism, which your blog seems to suggest is no problem.]

This thread seems a good one to hitch a lift on because there is bound to be someone with experience of the Coronado PST. I'd really love to get some information about using them. I just got one on eBay (I know: caveat emptor etc.) and the sky has really never been crystal clear since it arrived. Hence I haven't had an opportunity to test it properly. I am aware that the image looks dim and that getting features requires some subtle twiddling of the filter control. So far, I have used it with a couple of eyepieces and with a X2 barlow (also with my DSLR) but never managed to get a crisp focus. I can go through a 'best' condition so I don't think I am at any end-stop of focus. The PST has a non-standard focus control so I don't know what to expect but is it normal to find the image moves from side to side as the focus knob is turned? I could take off the side panel and that may give me a clue about how the focus actually works but I am reluctant to because I may need to return it. The absence of sunspots at the moment really doesn't help. My DSLR images have dark spots but they are dust!! I blew them away, ready for my next sunny day session.

That brings me to another question. Everything was torqued up very tight and I could find no 'civilised' way to unscrew the polarscop from the tube it sits in. (I assume the thread on the polariscope goes into a threaded bore). I looked for a set screw, holding the scope into the mount but found none . Do I need to get out my large stilsons? Sounds good and easier to get the head to it in the home position than kneeling down with your head at an awkward angle. I imagine the reticule needs a bigger range of adjustment, though. But the question still stands about the wobbling reticule. It's disconcerting.