My 2.2m dome arrived today

[Laurin Dave]

15 minutes ago, Rusted said:

There was mention of the green Pulsar getting rather warm in sunshine.

How does the white one do in hot summer sunshine?

Mine stays around ambient, maybe 1 or 2 deg C higher in direct sun but nothing to worry about,  as my wife discovered last week once inside it feels much cooler than outside as you're out out of the sun..

Dave

[Rusted]

1 hour ago, Laurin Dave said:

Mine stays around ambient, maybe 1 or 2 deg C higher in direct sun but nothing to worry about,  as my wife discovered last week once inside it feels much cooler than outside as you're out out of the sun..

Dave

Hi Dave,

Thanks for the swift reply.

That is really great news for solar imagers like myself. 

 

[steppenwolf]

18 hours ago, Laurin Dave said:

Mine stays around ambient, maybe 1 or 2 deg C higher in direct sun but nothing to worry about,  as my wife discovered last week once inside it feels much cooler than outside as you're out out of the sun..

Dave

This is my experience too - it really does pay to stay with the white finish.

[sloz1664]

I really wanted the green Pulsar dome, but when a good second handwhite  dome came on the market at the right price I snapped it up. I am now glad of the colour, even on the hottest of days it doesn't feel too hot to the touch. Whereas I have a dark green storage bin and this gets too hot to touch in similar weather.

Steve 

[tooth_dr]

I've made some progress, and last night I tried the motors to see how the dome rotates.  It went ok for a few turns, then it got stuck at the same point each time.  I lifted the dome up today, and did some filing/sanding, to reduce ledges on the internal surface that presses against the wheels.  This seems to have done the trick.  I can control the dome rotation and shutter opening and closing using the Shelyak Dome Tracker test software, all that side of things is functioning correctly.

I have ran the calibration test several times, and I get a maximum deviation of 6 steps over 9 runs, scoring between 6310 and 6316, where the average is 6312 steps.  I assume this is satisfactory?

I need some help now, if anyone is able to throw a few pointers.  I am going to do the measurements later this evening using the guide published by Steve Richards aka @steppenwolf .  Where is wall height measured to - is it literally to the top of the wall panels from the ground?

If I'm using SGPro - POTH or Shelyak Dometracker (sorry if this is a dumb question!)  My dome comes with the Shelyak Controller, but i read about people using POTH, although there is a specific ascom program for it.

 

Thanks in advance

Adam.

  

 

[Davey-T]

Don't know if it has any relevance to your situation but the latest ASCOM V6.5 have larked about with the POTH thingy.

Dave

[tooth_dr]

3 minutes ago, Davey-T said:

Don't know if it has any relevance to your situation but the latest ASCOM V6.5 have larked about with the POTH thingy.

Dave

Thanks Dave, did a quick search and see that 6.5 indeed says:

"A new Device Hub replaces the POTH, Hub, Pipe and ASCOMDome hubs."

[steppenwolf]

Adam, you could use the height from my spreadsheet as we have the same observatory but the wall stops where the dome curvature starts so you measure from there to the same base level as the foot of the pier.

[tooth_dr]

Just now, steppenwolf said:

Adam, you could use the height from my spreadsheet as we have the same observatory but the wall stops where the dome curvature starts so you measure from there to the same base level as the foot of the pier.

Thanks Steve, the spreadsheet, in particular the diagram are very helpful.  I should have bought a mark1 mesu.

[tooth_dr]

That’s the construction complete. Did a rough PA last night, so can start taking measurements today.

 

[tooth_dr]

I’m trying to do the measurements but the wedge is throwing me.  I’m using @steppenwolf guide on S@N and it shows the measurements for a mesu mk1. Because I have the mesu mk2 which has no adjustments as such and uses a wedge, I’m not sure where to measure from. Any assistance greatly appreciated 🙈

Specifically measurement ‘a’ - in my case is it from the bottom of wedge plate, where it bolts to the pier plate?

 

 

[sloz1664]

I would use a theoretical point at the centre between your angled bottom plate and your adjustable plate. As this, if adjusted, is your pivot point.

Steve

[tooth_dr]

10 minutes ago, sloz1664 said:

I would use a theoretical point at the centre between your angled bottom plate and your adjustable plate. As this, if adjusted, is your pivot point.

Steve

Something like this?

[michael8554]

I'd say it's pivoting about this point, "h" will change as you adjust but take the final figure of course:

 

 

Would there be less chance of the three adjustment bolts flexing under load if they were on the other horizontal joint at the top of the pier ?

Michael

 

 

Edited June 17, 2020 by michael8554

[tooth_dr]

2 hours ago, michael8554 said:

I'd say it's pivoting about this point, "h" will change as you adjust but take the final figure of course:

 

 

Would there be less chance of the three adjustment bolts flexing under load if they were on the other horizontal joint at the top of the pier ?

Michael

 

 

Thanks Michael. That’s a good point about the bolts. Looking at it again, I could at least bring down the top bolt on the wedge to as short as possible, that would help a bit.

I hadn’t thought of doing the adjustments closer to the pier on the lower horizontal plate.  That should work too? I have no way of rotating the pier ie no azimuth adjustments but the tilting should take care of that?  I calculated the position of the pier theoretically and with it all bolted level I think I was about 1 degree out according to sharpcap.

Edited June 17, 2020 by tooth_dr

[steppenwolf]

This is where I think it is on your mount too:-

[tooth_dr]

6 minutes ago, steppenwolf said:

This is where I think it is on your mount too:-

Thanks Steve for the confirmation 

[steppenwolf]

5 minutes ago, tooth_dr said:

Thanks Steve for the confirmation 

No problem, here is another dimension for you (d):-

[michael8554]

5 hours ago, tooth_dr said:

I have no way of rotating the pier ie no azimuth adjustments but the tilting should take care of that?  

Nope

To Drift Align you will need to adjust the Alt pointing east or west, and then pointing south you will need to adjust the azimuth.

5 hours ago, tooth_dr said:

I think I was about 1 degree out according to sharpcap

1 degree is 60arcmins, you should aim for about 5arcmins maximum.

There might be enough wiggle-room in the bolt holes to dial out that 1 degree error, otherwise elongate the two south bolt holes so that the mount can be levered that small amount around the north bolt.

Michael

[tooth_dr]

1 hour ago, michael8554 said:

1 degree is 60arcmins, you should aim for about 5arcmins maximum

Sorry Michael I don’t think my comment was clear.  I didn’t mean my final PA was 1 degree out. When I first plonked the mount onto my pier, without any adjustments, it was 1 degree out.  I thought this was pretty good for using a compass to align my pier and accounting for the difference between magnetic and true north.

Following precise adjustment of the wedge I have it to within 3 arc seconds (according to Sharpcap so how accurate this actually is is debatable).

1 hour ago, michael8554 said:

To Drift Align you will need to adjust the Alt pointing east or west, and then pointing south you will need to adjust the azimuth.

I’ve never drift aligned a mount before.   @Jonk I think Jon drift aligns his Mesu e200 though?

 

[Jonk]

3 hours ago, tooth_dr said:

I’ve never drift aligned a mount before.   @Jonk I think Jon drift aligns his Mesu e200 though?

I have tried all sorts of alignment techniques, and I have found that for me, drift aligning is the easiest to understand and seems to just work.

Drift aligning a Mesu e200 mount shouldn’t be any different to any mount apart from the 3 bolts are acting like a primary mirror collimation rather than alt/az adjustments in a typical wedge.

It really isn’t scary to do and like anything, a bit of practice and understanding what you’re doing and why is always a good thing.

[tooth_dr]

9 minutes ago, Jonk said:

I have tried all sorts of alignment techniques, and I have found that for me, drift aligning is the easiest to understand and seems to just work.

Drift aligning a Mesu e200 mount shouldn’t be any different to any mount apart from the 3 bolts are acting like a primary mirror collimation rather than alt/az adjustments in a typical wedge.

It really isn’t scary to do and like anything, a bit of practice and understanding what you’re doing and why is always a good thing.

Thanks Jon.  I may look into it, but I seem to have pretty decent tracking in Dec without guiding, so what I'm doing with Sharpcap may well be sufficient.   I find the adjustments to get PA quite straightforward with the three bolts, and in fact no more difficult that using alt-az bolts on my EQ6.  I was just checking that drift aligning can be done with the Mesu mk2, in relation to Michaels comment above.

[michael8554]

3 hours ago, tooth_dr said:

Following precise adjustment of the wedge I have it to within 3 arc seconds (according to Sharpcap so how accurate this actually is is debatable).

So why were you asking about Az adjustment ?

Michael

[tooth_dr]

24 minutes ago, michael8554 said:

So why were you asking about Az adjustment ?

Michael

Thanks for your help Michael, I have the measurements sorted now.

 

Adam. 

[tooth_dr]

Here are a few photos from delivery to completion of dome.

 

I bought the dome and it was kindly delivered by the previous owner in September last year.  It came with all the electronics that I wanted - dome rotation and shutter drive.

 

 

Edited June 19, 2020 by tooth_dr