My New Pulsar 2.1m Obsy - Finished :-)

[Jkulin]

31 minutes ago, Nigella Bryant said:

Brilliant, your dome build has come on very well, even after a few hiccups. I'm still only at the wall stage, lol. Weather disruption stops play, lol. Can I ask what drive you have for the dome? I've an older type pulsar 2.7m and would like to add a drive to the dome. Not bothered about the shutter. 

 

Thanks, but I can't take the credit, @Steve 1962 designed and built the motorised system for all, all I had to do was put it back together again.

Essentially there are two stepper motors controlled by an Arduino, Steve developed the software and then worked with a programmer in Las Vegas, a cambelt is bonded to the dome walls and one stepper motor is sprung against to for the dome rotation, the other motor drives a pulley to open and close the shutter, if you need any more photos then I would be happy to provide them.

Steve had planned to build it all into one box, but didn't get round to it, once I feel comfortable with it, then I may do that and potentially change the shutter to chain driven rather than cord driven, but that's a long way off.

Today's project is to remove the cambelt and fit the new one piece version.

HTH

[Nigella Bryant]

18 minutes ago, Jkulin said:

Thanks, but I can't take the credit, @Steve 1962 designed and built the motorised system for all, all I had to do was put it back together again.

Essentially there are two stepper motors controlled by an Arduino, Steve developed the software and then worked with a programmer in Las Vegas, a cambelt is bonded to the dome walls and one stepper motor is sprung against to for the dome rotation, the other motor drives a pulley to open and close the shutter, if you need any more photos then I would be happy to provide them.

Steve had planned to build it all into one box, but didn't get round to it, once I feel comfortable with it, then I may do that and potentially change the shutter to chain driven rather than cord driven, but that's a long way off.

Today's project is to remove the cambelt and fit the new one piece version.

HTH

Thanks, I'll pm you.

[Steve 1962]

@Nigella Bryant

Please feel free to PM me if you need any help / advice.

ATB

Steve

[Nigella Bryant]

1 minute ago, Steve 1962 said:

@Nigella Bryant

Please feel free to PM me if you need any help / advice.

ATB

Steve

Thanks Steve.

[Jkulin]

@Nigella Bryant You should have had an email from me, I've done the internal photos for you and will send them shortly, hope they help?

Well replacement belt fitted quite quickly.

Now pratting around this afternoon, my good mate Mark @Toxophilus very kindly calculated his perception of all the offset as he is a lot brighter than me and also owns a 120EC, so I inputted them into SGP and slewed to a target in CdC and so far | think it might be working, it threw me completely as you don't think it is going to get the target in line, but I think it may have, so I have left it to guide on a test target and hopefully it will remain on target.

The mount slews first and then after what feels like an eternity, but is probably only about 60 secs, the dome then moves to its position, I'll let you know how it gets on.

[Jkulin]

Well, I decided to recheck my pier measurements as I wasn't quite sure if I had taken them from the correct place.

These were the offsets that Mark had calculated for me, so @steppenwolf maybe they might help your mate Steve with his 120, as he could input his own Pier Offsets and the only thing he would have to change would be 'h'

It#s not been running long enough yet, so will let it run for a few hours before trying a different target, then I need to force a flip and see how it responds.

[Steve 1962]

Quote

The mount slews first and then after what feels like an eternity, but is probably only about 60 secs, the dome then moves to its position, I'll let you know how it gets on.

Hi John

That'll probably be because the update interval in the driver slave settings is set to 60secs. If you want it move sooner, try reducing this..

HTH

Steve

[Nigella Bryant]

1 hour ago, Jkulin said:

@Nigella Bryant You should have had an email from me, I've done the internal photos for you and will send them shortly, hope they help?

Many thanks John, received then, much appreciated.

[Jkulin]

56 minutes ago, Steve 1962 said:

Hi John

That'll probably be because the update interval in the driver slave settings is set to 60secs. If you want it move sooner, try reducing this..

HTH

Steve

Thanks Steve, yep seems obvious now you mentioned it, what do you reckon, drop it to 15 secs?

[Jkulin]

Well the figures that Mark did for me appear to work, I artificially slew to M13 and it kept that bang in the middle for over an hour, still more playing around to do and I want to experiment with the Ascom (rather than the Arduino) interface just to satisfy my curiosity.

I need to be 100% confident in what I do before I can use something properly, so a good day on it tomorrow, may allow me to have a play next week.

[Steve 1962]

Quote

Thanks Steve, yep seems obvious now you mentioned it, what do you reckon, drop it to 15 secs?

No harm in trying that John.

Quote

I want to experiment with the Ascom (rather than the Arduino) interface just to satisfy my curiosity.

Again - there's no harm in trying that but I would point out that whatever software you use (SGPro, ASCOM dome etc) interfaces with my Arduino ASCOM dome driver, which in turn just sends and receives codes to and from the Arduino. So whatever software you use should work equally well - having said that, I never tried the driver out with ASCOM Dome so I'll watch with interest!

For information, the software uses a series of standard methods and properties to communicate with the ASCOM driver and the driver converts these to the Arduino's "language" of 997 and 996 codes. Attached is the webpage showing the ASCOM methods and properties used.

https://ascom-standards.org/Help/Developer61/html/AllMembers_T_ASCOM_DriverAccess_Dome.htm

So as a simple example, if you press the Open Shutter Button in SGPro, SGPro sends an OpenShutter method to the ASCOM driver which translates this into 997,801,998 and sends it to the Arduino.

In just the same way, when the software needs an update, it sends a Get Property method to the ASCOM driver, which converts the query into a 996 string to the Arduino. The driver listens to the response from the Arduino and converts it back into an ASCOM property which it passes back to the software.

Simples!!!

Steve 

Edited July 5, 2020 by Steve 1962

[Jkulin]

Hopefully First Light tonight for me, and I'm really quite anxious!

My RC is back in place now, it took me a while to get everything talking together as previously I had used my laptop and now everything will be controlled via my spare PC.

Some test slews in CdC seemed fine, looked a bit tight but was clear, so lets see how it does when it has to slew for real.

Skipper Billy has very kindly helped me get some 2 Pack Paint, so will hopefully get that on in the week if it isn't too hot.

[Nigella Bryant]

15 minutes ago, Jkulin said:

Hopefully First Light tonight for me, and I'm really quite anxious!

My RC is back in place now, it took me a while to get everything talking together as previously I had used my laptop and now everything will be controlled via my spare PC.

Some test slews in CdC seemed fine, looked a bit tight but was clear, so lets see how it does when it has to slew for real.

Skipper Billy has very kindly helped me get some 2 Pack Paint, so will hopefully get that on in the week if it isn't too hot.

Looking good.

[Steve 1962]

Looking great John - hope it goes well!!

[Jkulin]

Just now, Steve 1962 said:

Looking great John - hope it goes well!!

Thanks Steve, if it goes pear shaped with the offsets then I have a couple of months to sort, thanks for all your help.

[Steve 1962]

No problem at all John. Re the offsets - just remember that it doesn’t matter where the scope is pointing - if your offsets are correct, the dome should align itself so the scope sees through the middle of the slot.

You can simulate and tweak this to your heart’s content in broad daylight - and because you can run with the shutter closed, you can even do it when it’s raining! 

[Jkulin]

Thanks Steve, these were the offsets we came up with for my Mount, and OTA: -

I've since changed the update frequency to 10s and will see how that works, originally I had the allowable error at 5 degrees, but I think that was a little too much with a 2007mm OTA

[Jkulin]

Well I managed first light with a 20min sub of NGC6888, I had previously managed just 8 x 1200s of Ha at the beginning of June, so I thought I'd just run a few off to see if everything was working, indeed it is, had a few hiccups with the FW drivers not working and didn't manage to get this sub until 02:30, this is just a single sub, no flats, nothing apart from a quick stretch: -

And the moon is up now, so at least I managed to test it out.

I need to redo the balance and calibration, but otherwise it looks promising, once I can get all the data captured.

[Swoop1]

I think that something working not perfectly but functionally after all your effort John, is a result.

The rest is just gravy.

[bob-c]

Well done John, looking great mate.

Bob.

[RayD]

I've just re-read this thread and I'm positively exhausted!  I admire your get up and go and determination, John.  I'm just glad I have a simple ROR, which seems easy peasy by comparison.

Here's to many hours of happy imagining in and from that little beauty 🍻

[Jkulin]

1 hour ago, RayD said:

I've just re-read this thread and I'm positively exhausted!  I admire your get up and go and determination, John.  I'm just glad I have a simple ROR, which seems easy peasy by comparison.

Here's to many hours of happy imagining in and from that little beauty 🍻

Thanks Ray, I hope it was worth reading ...lol

Yes a RoR would have been so much easier, but a shed or summerhouse smack in the middle of the garden would not have looked right and if I am honest it doesn't look too bad now and will look even better when painted.

More importantly it works perfectly on the offsets which was a worry.

Anyway you are in Spain you should be enjoying the local vino not reading through all my trials and tribulations 🙂

[RayD]

23 hours ago, Jkulin said:

Thanks Ray, I hope it was worth reading ...lol

Yes a RoR would have been so much easier, but a shed or summerhouse smack in the middle of the garden would not have looked right and if I am honest it doesn't look too bad now and will look even better when painted.

More importantly it works perfectly on the offsets which was a worry.

Anyway you are in Spain you should be enjoying the local vino not reading through all my trials and tribulations 🙂

Oh it is definitely the perfect solution and fit here, John, just admiring your dedication to it.  It looks great and seemingly operates just as well.  

It looks superb, inside and out 👍

I do sometime wished I did drink just so a could have a nice Rioja. However, the alcohol free beers are a good substitute for me and plenty of them are being had 😉

[Jkulin]

Well I spent most of the morning sanding, so this was before: -

I've managed to get two coats on the walls, but only one coat on the dome, will get another on tomorrow.

Big thanks to @Skipper Billy for sorting the two pack paint out for me, top bloke!

This was the only green that International paints do, so maybe in the future I might mix it was a little black to bring it down a little.

But it looks a hell of a lot better than before and should not need polytrol on a yearly basis.

So nearly there now, then I can relax a little before my next project.

After: -

Edited July 19, 2020 by Jkulin
typos

[Davey-T]

Looks really great John, good job 

Dave