Jkulin

Well problem solved with regards to the jumping...you know when the obvious is staring you in the face but it isn’t obvious? Well I had a spare couple of hours today and was determined to get to the bottom of it🥴

The sticking was not sticking in that place that I thought, I released the motor drive and slewed it by hand, listening all the way round and it transpired that it was this...

At about 150 degrees opposite although I couldn’t see it, I could hear it, there’s a few of these bolts in place for safety to stop the dome lifting in high winds and it was catching on the rim, removed the bolt and all is well...happy days.

Quick call to Steve admitting my failure to diagnose the fault first time round and then Steve kindly went through a few checks to make sure that the home position was working correctly.

So hopefully I can now progress with getting the offset figures calculated and checked.

Thanks for everyone’s input but none of you can take into account my own stupidity.

The reason why it didn’t stick when I put the roof on was because I didn’t fit the securing bolts until I knew everything was running smoothly.

I have ordered a new cam belt that I will fit at the weekend, otherwise it will become one of those jobs that you planned to do but never got round to🙄

So let the headaches begin.

48 minutes ago, Xsubmariner said:

Hi John,

It looks to me like your dome or sidewalls are not quite circular which is causing the drive motor to to skip. Can you disengage the motor and try rotating the dome by hand to check for tight spots.

While my dome drive mechanism is different I have a couple of tight spots that were overcome by increasing tension on the drive wheels. 

Thanks Martin, she rotates really freely when the motor is disengaged, that was the first thing I checked when we lifted the lid on, Steve hinted that perhaps that I needed to increase the tension, so I'll have a look if I can tomorrow.

Thanks for the input.

Right so as I had an hour or so to have a play, I thought I'd check that all the mechanics work as there is no point setting everything up unless it will work.

So first thing with some trepidation I told the dome to raise the shutter, with screaming and stuttering half way up I knew something was wrong, it turns out the new wooden stop that I had fitted was fouling the cable ties that was holding the Cat5 cable in place after I repaired it from having to cut it to separate the roof, once that was sorted it would raise and lower manually, so time to try the motor...not a good idea as I had wound the cable incorrectly and it had come out of its guide, I may have to look at a smoother more efficient way to raise the shutter but at least now it is working and shutting off correctly.

So now comes to check the rotation, I wasn't worried about how it did it as long as it was smooth, first job was to tell it to find zero, yep the new zero position was working and cutting the motor properly, so the next job was to tell it to rotate to the North, this is where I had run out of time, but not before I had come across another problem that I haven't got my head around yet, see the video below: -

So it runs along nicely but snags in this particular spot and will not get itself out of the mire, I can't see anywhere that is is catching or that the aluminium rail is not lined up smoothly, I can't see any wear to the belt, so am really at a loss, I've asked Steve for his thoughts, but would welcome anyone else's ideas.

So until I have worked this out then, there really is no point of moving forward, I have ordered just in case 10m of replacement timing belt, in case the issue is down to wear or poor alignment on my behalf, but as it is fitted with EvoStik impact adhesive it might be a pain to remove.

So some positive news and some head banging non-progress, I have got to get to the bottom of this first.

Many Thanks @Laurin Dave and @steppenwolf I truly appreciate your thoughts.

Its been pandemonium in the office today and it is chucking it down outside, so as soon as I get a breather then will go out and play, thanks once again.

Thanks Martin for the reply, much appreciated.

I have never used the POTH facility, so am a bit green about how to interface that, can you brief me a bit please?

Steve worked with a developer to create an Ascom driver based on an Arduino unit, Steve really did a cool job on it, but I'm just struggling to convert the parameters out, so any thoughts about how I can integrate the POTH into SGP would be most appreciated?

Many Thanks.

Thanks Dave, much appreciate you help, when you feel refreshed can you advise where to take the d measurement from and where does the a end and the t begin, sorry about all the questions?

46 minutes ago, Laurin Dave said:

Hi John ..  I believe the reference point (RA centre on the Mesu diagram) for the offsets is the intersection of the RA and Dec axes..  which for your mount looks to me as the point between the two RA bearings..  rather than where it looks to me that you have it (just below the dovetail clamp) you need vertical and horizontal offset of this point from the centre of your pier ( to add to your pier Offset measurements) ..and the GEM offset which is the distance from the reference point to the centre line of your scope ..  

HTH And that I’ve understood your diagram ..  looking on my phone

Dave

Hi Dave, thanks for your help, I'm probably being stupid, but looking in the manual the RA Axis is what I think I have used: -

So I have just been out to remeasure and amend the measurements on the image, have I got it totally wrong?

Apologies for being a pain?

@tooth_dr Thanks Adam for pointing @Xsubmariner my way, hopefully now that I have double checked all the measurements Martin might be able to advise.

I have posted a copy of the spread sheet with my dimensions on for the 120EC, can anyone comment or advise if they think my dims are correct? I believe this is a 2.1m dome rather than the 2.2m: -

I truly would appreciate anyone's thoughts before I start to play with the software, for some apparent reason which is unlike me, I am apprehensive to get it wrong?

On 28/06/2020 at 09:30, tomato said:

Looking really good, brings back memories from last year when my second hand Pulsar Dome went up. 
Just a tip on the painting, my wife wanted a green dome but In my haste to do the job I attempted to paint the dome section in between showers with the result that the paint did not exactly dry to a high gloss, so will need to be redone later this summer.

Thanks yep I will only do it when it is forecast to be bone dry but not red hot, Skipper has been advising me and he's a real pro.

We've had non stop but rain up until about 17:00, but finally managed to get the top on and secured, excuse all the white marks, they are mostly dust from the sanding, just a few tweaks tomorrow of the seams and then with some of Steve's help I can sort out the new Zero Position as I swapped some of the panels round so that the Bay was pointing away from our home and the door was facing straight towards the future path way.

The aluminium curved rails for the dome to rotate on were re-aligned because of the changes and the dome will almost rotate freely a complete rotation with a simple push.

The cord for the shutter has come undone, so I need to work out how to feed that correctly and fit a couple of stops for the auto cut-off, Steve was taller than me so he could easily reach, but it will make things easier knowing that the auto cut-off stops are working.

I'm going to redo the flooring as I want it to extend fully to the edges so there is no chance of dropping anything through.

Next jobs will be to resite the monitor, build a few custom shelves and my mate is coming over on Friday to do the electrics. I also need to site my flat panel and run the cabling for the computer within new trunking.

After that my only worry which is giving me serious concerns is the offsets, but will face that challenge when I am ready.

I have set mine up with VNC to change any settings then use the GUI front end via my web browser to download files, it really is very easy.

I haven’t worked out how to ftp the files as it means leaving it open and my provider only leaves the access open for a limited time.

Apart from the fact that I haven’t worked out how to do the settings on the RPi for FTP.

I'm just sorting mine out at the moment and finally went with a RPi because I need to use WiFi because of the distance, I'm using Thomas Jacquins software https://github.com/thomasjacquin/allsky but the only problem is that it currently has to use a ZWO camera as he has only configured using the ZWO sdk, he is currently working on using the QHY and then hopefully the Altair, as I bought a Altair 178MC but unfortunately it doesn't work with his software yet and I'm not clever enough to reprogram the software.

So I managed to grab a ZWO 178MC off fleabay and will use that.

Beware as others have said about too long USB cables, you are limited to 5m with USB 2.0 and I believe 3m with USB3.0, I needed about 7m so thus the reason why I had to go with the RPi otherwise I could have used the Altair.

3 minutes ago, Steve 1962 said:

Looking good John. Following progress with great interest. Wouldn’t the Polytrol sand off??

Hi Steve, Thanks, unfortunately after spending 4-5 hours with C30 and a DA it wouldn't budge hardly any of it, so after chatting with David (Skipper Billy) I'm going to coat it with a 2 pack from International Perfection and from the colour chart it looks very similar.

47 minutes ago, Xsubmariner said:

While originally offset south for my LX200, I needed  to centre the pier within the Pulsar 2.2M dome for my CEM120EC2. During commissioning I needed to make slight adjustment to the dome control GEM offset value to find the best alignment. 

To find the best setting I plotted the scope alignment to the dome slot by slewing the mount/dome to positions of Azimuth (every 20degrees 0-360) and elevation (10,20,40,60,80 degrees) using POTH in Ascom. While tedious, in the end I managed to get a good compromise where the scope was hardly shaded by the dome.

Perhaps one of the mathematical experts here can explain why the dome geometry model for GEM didn’t seem to work as accurately for CEM mounts. 

Thanks for that, I'll have a play once it is all connected up, any chance you could do a screen grab of you settings please?

Well today has been absolutely exhausting, I'm shattered.

I thought I'd spend some time preparing the dome and for the Polytrol treatment, after 4 or 5 hours of using C30 it wasn't shifting, so I have resigned myself after chatting to Skipper Billy to using a 2 pack Coloured Paint, which I will do once it is all up and running.

So the walls are now up, bolted down and sealed, the aluminium rails for the dome are all aligned, so tomorrow is going to be a big ask from my family to lift the dome into position, once secured I can then complete everything with regards to connecting everything up.

1 hour ago, steppenwolf said:

Sorry, I have only just seen this! I'd love to give you a definitive answer on this but recent experience with a friend's 120 have proven to be very inclusive. It shouldn't be that difficult but for some reason, we have yet to get the system to sync the mount and dome together correctly. Now, it could be that there is an issue elsewhere in the system as his dome has never synced as well as my own but he's certainly having issues with the 120 now.

If it gets resolved, I will post up the solution here.

Thanks so much Steve for taking the time to reply, it is appreciated.

Sorry Jake, but I still can't see any of your videos, they all have a no entry sign.

With horrendous rain yesterday and today it has stopped play! 😞

Everything is sitting covered where necessary, I just need to clean up the old silicone and then clean and apply the Polytrol and then assemble.

We had hoped to get it into the Luton Van in two pieces, but sadly my interpretation of a Luton Van and the Modern day interpretation are completely different, we had to split the top and bottom in half, no big deal real as the silicone came apart with the windscreen removal tool very easily, I had to cut a Cat 5 cable to split the dome, but that is an easy fix.

My lads and Steve did me proud as I can't lift easily because of the c0ck up to my spinal surgery in January, so all I can do is get everything clean and get my lads round to help lift it all in place.

I've still got to resolve the offsets with a CEM Mount, but I have time for that anyway.

As long as rain doesn't stop play further, then I would hope to have it all up and running in two weeks.

Thanks Adam, I'll have a look at that.

Edit: - Ok As mine is a CEM any idea where I should get a (RA Centre), d (RA Centre Offset), t (GEM or CEM in this case of the Axis Offset) and finally h (RA Centre Height), @steppenwolf Steve can you point me in the right direction?

Many Thanks.

Just found this link which appears easy to understand, but is that correct: -

https://www.nexdome.com/single-post/2018/08/21/How-to-calculate-telescope-pier-height

Right picked up the dome from Steve today, what a smashing helpful person, really patient.

Can anyone advise, this might be a similar question to Adam @tooth_dr, but slightly different in that I don't have a GEM but a CEM.

So I believe I need to calculate the offset for the mount height, please feel free to correct, but as I understand, I take the zero offset from the base of the Dome where it meets the walls? Then I take a position from a midway point of the mount, or have I got that totally wrong, in the image below I am presuming that that point is where the middle red locking nut is on the Losmandy saddle, is this right?

If I have it wrong can someone advise is very simple English please?

Many Thanks.

Cheers Ray, yep Steve is an engineer and has made a truly tidy job, he says we just have 4 bolts to undo and then separate the sealant from the Cement base, so I bought a couple of these which should help.

My Son and Son-in-law are travelling down separately in the Luton Van, so with a bit of luck we'll get it in in two pieces.

18 minutes ago, RayD said:

Very exciting, John.  Just need the lid now!

Yep Ray, I'm almost ready this end, just a few more connections to solder up, wire the feed to the ASC, a little trepidation setting it all up as Steve has a custom Ascom driver and interface, so will have to get that established in SGP, will know on Wednesday when we travel down,

Here's a Video Steve sent me of the control working: -

I must make a compliment to him how well he set this up.

Spent Friday and Saturday fitting the floor boards and then finished off just before the rain the flooring, which I had from ages ago, contact adhesive secured, now just need to do all the connections but need the rain to stop:-

2 hours ago, SteveBz said:

Great. Thanks for that. Do you know its height?

Steve.

 

All I have is the drawing from Pulsars web site, this is the reason why I have built mine thee bricks high, see this thread: -

22fullheightdr.pdf