cwis

Bit more progress! Magnet holding screw and lower profile screw fitted. Had to hacksaw the original lower hand screw off - due to a poor fit it had galled being soft aluminium and I couldn't get it out.... It had bottomed out in the thread/on the shoulder of the bolt and wasn't clamping the bearing - it was resting on the bolt and cutting in to it. I've put washers behind the remaining original bolts - might be worth looking at if you have one of these. I had to print spacers for the above screws cos I gave the machinist the wrong numbers. We'll call these version 0.1 and get some more made - luckily I married his sister so he owes me.... Wrap tape round the mounting guide until it's a snug fit in the azimuth bush, put it in place and mark the mounting holes for the azimuth sensor and reassemble the base: Immobilise the lower bolt: Temporarily fit the sensor for testing. Version 0.2 of the sensor mount will have slotted screw holes to make alignment easier. Next - The Altitude sensor. I'm going to route a mount out of ply and clamp it to the base for version 1. I think I'll be mounting the microprocessor to this too. I HATE routers so I'll be girding my loins and counting my digits first.... It should occur this weekend.

Yeah it's a lovely bit of kit and more in line with my stated requirements but I still think it's overkill for my application. It's basically a piece of scientific apparatus! My goal is something with a far lower level of precision. I'm not going to be seeking out dim hard to find tiny objects from my light polluted back garden so don't require that level of accuracy. I'm not actually sure WHAT level of accuracy I'm going to get, and that's one of the things I'm finding interesting about this little project. As a newbie I could buy another eyepiece with the difference in cost between my implementation and one made by a skilled grownup - and that's without buying encoders that suit the Nexus - I've not even looked how much they cost. Mine were 30 quid.... If I was willing to do the I2C implementation myself they would have been less than a tenner. I'll pay 20 quid to not solder surface mount stuff... I've got my kit talking to Sky Safari now via Bluetooth so the last bit is mounting on the 'scope. I actually think this will be the hardest bit!

Right - that's better, pics show in incognito mode too. I had a look at the Nexus along with many other systems and although it's a great system (fantastic, even!) it's far more than I need. I don't need a star catalogue - Sky Safari has one. I don't need an OLED display or GPS, my phone has those. etc. Nexus is designed to be stand alone - where as I will always be using mine in conjunction with a phone, table or laptop. I'll power it off a USB pack so don't even need an on-board power source. My base functionality is: 14 bit encoders with noise suppression, linearity, averaging etc etc for probably 0.1 degree accuracy (maybe 0.05 if I mount the magnets well) , and bluetooth capability to connect to an application written by grownups.

Oh yeah that is broken! I'll have another go... Cheers!

In short: I have a Bresser 10inch dob and want pushto via Star Safari et al. I have a garden with restrictive views and star hopping is a little frustrating. I had a look at available solutions available and decided it would be tidiest and most satisfying to roll my own. I started off experimenting with magnetic 12 bit rotary encoders (here's one mounted to the azimuth axis on a little 3D printed mount). The magnet is mounted to the pivot bolt below and the bolt held stationary so it does not move relative to the dob stand - so turning the mount rotates the magnet relative to the sensor. Results were very encouraging so I splashed out on some 14 bit sensors on their own I2C development boards (with matched magnets). After some time working out the i2c commands etc to pull meaningful data from them on my test rig (Raspberry Pi Zero using Python): I moved to "production" with an ESP32 development kit - I could solder plugs on directly for neat, easy, robust connections, I could use two hardware i2c buses so I didn't have to change the default configuration of the sensors to use different addresses or have any extraneous wiring connecting the two sensors together or use flaky software buses... (I used pins set digitally high to power the sensor boards - power draw was fine doing this, but I did use the actual proper ground pins). (BTW I hope you like the carpet in the spare room. Genuine '60s - It's not one for looking at with a hangover!) After an issue with a dry joint on a clock pin was diagnosed using the worlds cutest oscilloscope: That's I2C right there. You can even see the weak pullup resistors on the ESP32 making the return from ground back to 3.3V slower than ideal.... Mind you my cables are a bit long - I'll trim them when it's on the scope. Next- print some mounts that are a snap fit for the sensor boards, print something that snap fits in and provides a pin to centre the mount on the dob base: The taper is a bit messy - printing PETG on a printer set up for ABS so there's no part cooling fan. I should have printed 4 copies of it so each layer had a chance to cool. Nevermind. Ask a grownup with a lathe to make lower profile replacement screws for one of the Alt bearings out of aluminium - One with a recess for the magnet: I pick those up tonight... More soon!

True but changing your wifi settings as per your first message shouldn't have broken anything. Try: Turn off home router (just to remove it completely from the issue) "Forget" Synscan_nnn network on one of your tablets (this will remove any remembered settings from previous experimentation) Turn on mount scan for networks on the tablet connect to Synscan_nnn one if it pops up (if not you have an issue but this should be fine because you did factory reset on the mount) Then fire up the Synscan application. Fingers crossed!

From the original post the connection to the mount SSID had been made, but the IP of the connecting device had been manually changed to 127.0.0.1. I don't think this issue is anything to do with using station mode or any of the other functionality of the mount - just the issue above. Forgetting the wireless network and reconnecting should fix. I've got this mount - the instructions could certainly be clearer (much much clearer!) but I've never had any issues connecting to it with a plethora of devices - including a joystick controller I made for it with an ESP32 running Micropython. I found looking at my phone to choose another goto target was destroying my night vision. IoT is certainly a rabbit hole...

Exactly - except the mount does not ask for a password when in wifi hotspot mode - it allows unauthenticated connections. The sequence of events for connection should be: Power mount on Turn off data via 3/4/5G if you are connecting with a device that has this functionality Open wireless networks (on your device) - you should see the SynScan_whatever network. Connect to it. This disconnects your current wifi network. You will be assigned a new IP address by the mount. Fire up The SynScan app. Hit connect (on the app). It will look automatically at the first IP address on the subnet you are on for the mount.

Oh yes - and turn off mobile data if your device has 3/4/5G ... That caught me out a few times....

So what happens if you try and connect the the available SynScan network shown above? It looks like the reset worked. You need to allow the unit to assign you an IP address - setting 127.0.0.1 will not work.

Mystery objects! I'm adding them to my Bresser 10" dob to give me push to... I tried star hopping with it but the views from my back garden are too restrictive really and I find myself getting out the little 130PS and its AZ-GTI for goto so I get to see things instead of just looking for things.... It's an I2C 14 bit rotary encoder. I ordered two - one for each axis. Been waiting weeks - on back order for ages....

I see! Yup - it didn't shift until I took it apart again. Would I buy the same scope again? Yes. It and the Az-gti are a stunning combo for a beginner. But I'd check its collimation the day it arrived. It ended up showing me some amazing views of Mars when it came back from FLO. I do seem to be having a bit of a run of luck though - first the 130ps, then a collimation cap with a non central hole, then a laser that was itself uncollimated and then the Bresser. Luck seems to be getting better (touch wood) I even used the Bresser last night! Star collimation was bang on and medium mags (150ish) were stunningly sharp even though it was a bit windy high up so happy days.

Thanks for the confirmation John! I did wonder whether I was missing something fundamental. I just need a clear sky now to see what difference (if any!) it's made. I keep looking at Concenters because although I'm a complete newby it looks like I like newts and I'm picky about collimation. You wait - this time next year I'll be saying in an adenoidal voice "Yes well I think the flint element is a little pinched in its holder in this example"...

Ended up here. Camera is slightly off centre but the eyeball shows a concentric white circle within the doughnut, with the Cheshire viewing hole and my eyeball in the centre. The Cheshire crosshairs are in line too showing the secondary is fine, and the three mirror clips are all slightly out of view but with a collimation cap are visible and equally spaced on the mirror. I replaced the longer screws with 30mm ones and as predicted they recess nicely without bottoming out: I really can't see anything wrong with this setup - I wonder if an accountant changed the spec of the adjustment screws from "30mm cross head screw" to "30mm knurled thumbscrew" without realising the implications?

Not sure whether I'm the member you are referring to here? My 130PS was supplied with the primary uncollimated (but no damage visible). We surmised it may have been dropped in transit or was perhaps uncollimatable from the factory and had slipped by quality control. After help and advice from you lot I sent it back to FLO and they returned it perfectly collimated - they had enlarged the mounting holes for the plastic lens cell to allow enough adjustment (which makes me think it was a one off uncollimatable 'scope from the factory). It has stayed perfectly in collimation since but the whole process gave me the confidence to improve and upgrade it, so I replaced the primary mirror cell with a collimatable one from a 130P. Focusser is next. It does make me wonder however how many people actually properly check collimation - I posted yesterday about my Bresser Messier 10inch dob because as supplied as far as I am concerned the secondary mirror cannot be put central to the focusser with the secondary tilt 30mm thumbscrews supplied - they are too short as the spider was designed with 30mm recessed screws in mind. So either everyone with a Dob-254 with thumbscrew secondary adjusters owns an uncollimated telescope, or I'm particularly unlucky and have been supplied with one with the wrong length thumbscrews and therefore the second uncollimatable telescope in a row. I'd say the odds are that I'm not the only person affected but the majority neither know nor care about accurate collimation as long as the views look OK and the laser spot lands in the middle of the doughnut.

Hi all, I THINK I'm right here, but please correct me if you see an error... I finally got round to trying to collimate my Bresser 10inch dob today. I've had it a few months (been cloudy for most of it!) and although I didn't really see anything wrong with the views I was having back in the distant past before the snows, I thought it was time to familiarise myself with it. Secondary first, as is customary and I saw that it was not central to the focus tube - it needed to move towards the primary mirror a few mm. So I loosened the central screw and wound in the outers. However before the mirror was central, the knobs bottomed out on the secondary holder: I had longer spare screws, so ended up here. I'm not finished but it's in the ballpark central now: This left the secondary mirror base this far away from the centre of the spider: Unfortunately the supplied screws are only this long: I notice olderDob-254 had screws instead of the knobs on mine. It looks like the spider was designed with recessed screws in mind: That well is 5mm deep, so a 30mm screw headed adjuster would work fine. Has no one else experienced this with their 10 inch Bresser? I thought quite a few have been sold recently - am I the only one to shift the secondary? I' will be replacing my 40mm spare screws with 30mm ones for tidiness btw in case they offend anyone's OCD...

V block assembly worked OKish - will need to rethink that to cut the CF tube. I've slapped it together precariously to see if the focusser is in the right place. With it all the way out I should just be able to focus on the end of my garden... And that's a yes! Excellent! Next steps are to 3d print some stiffeners for the tube to make it round, and then use it as a former for the CF tube. I'm going for usable, rather than pretty so not bothered with surface finish. It'll be grippy rather than shiny! Here's the project the CF is left over from... BMW R100 café racer tank.

Focusser test fitted! Just need to make up some v blocks now to rotate the tube on while I cut it to length as marked.

Many thanks! I think I've got the spherical mirror one - like you I'm not sure whether that has a bearing - a focal length is a focal length - right? I'm going to go with the stock secondary cell to begin with so both dimensions you have given me are very useful! I've got a bit of plastic pipe that I can cut and use to test and then wrap the carbon round - I'll get on with cutting it for a mockup! Thanks again!

Hi all, I picked up the primary and secondary mirrors from one of these second hand, I have a new Svbony focusser (far nicer than the Sky watcher standard one - it's metal!) and I'm going to make my own carbon tube - I've got some cloth and resin left over from a motorbike related project. I only have one question - how long is the tube? I have two estimates from pictures online of 850mm and 700mm - if anyone has one can they please measure it? Any usable dimension is fine, overall length, distance from the secondary "cell" to the primary, whatever is easiest. Many thanks!

Could you rotate the secondary mirror down a little? Either that or tilt the focuser tube upwards (if you have that adjustment).

Didn't say! Just got a mail from Steve on Thursday saying it was collimated and on its way home.

Hi all, Got my telescope back yesterday! There's no arguing with the below, is there? If it looks slightly out, that's my wobbly hand with my phone camera. I've tried to zoom in as far as I could digitally to show the accuracy of the collimation - It's bang on! Mirror clips all equally showing, hole in middle of doughnut etc etc... Unfortunately there also seems to have been a load of clouds in the box. Never mind - Mars hasn't got far so hopefully they will dissipate soon and I can try it out! Thank you @FLO!

They will fix or replace. I hope they can fix - got quite attached to it! Either way I'll be chuffed - I was thinking that the 'scope was quite a good compromise for a complete Goto solution that weighs just over 6.5Kg (that's 'scope, mount AND tripod for 6.5Kg!) but the hints of it's true ability on Mars just blew me away.

Update: With Auntie Flo's approval I loosened the screws holding on the primary cell to the tube of the OTA with a view to getting better alignment. The boltholes in the tube are slotted to assist in this, but FLO said this was the first one they had supplied that had required ANY adjustment at all - all the rest perfectly collimate when the secondary mirror is aligned correctly. The screws btw are surprisingly lightly torqued up - there are plastic threads in the mirror cell. Once I had done this there was a surprisingly large amount of adjustment - I could shift the central doughnut about 1/2 of the secondary mirror diameter by wiggling the cell about. Unfortunately this adjustment was not symmetrical about the position I first found the mirror cell in and there was not enough adjustment in the correct direction to line up the mirrors. I removed the screws completely and I could get it in the correct place, but then I couldn't get the screws back in. Rotating the cell was not possible as there is a cut out in it to accept the OTA tube seam. I reassembled the 'scope - pushing the mirror cell all the way home put the mirror back into the same place I found it according to my collimation cap, and informed FLO. It was picked up yesterday afternoon by a chap from DHL. Now I am without a 'scope I expect the weather to improve significantly....