Issues with HEQ5 calibration / home position

[adh325]

Hi there, hoping I can sponge some more of your expertise on this!

So I've recently started using ASCOM, which is great, but I've had some issues with calibration and the home position.

I've read a number of guides online about how this should be done, and I think I've done a reasonable job.  I aligned the polarscope in daylight using a distant point, rotated the RA axis until the reticle was pinpointed on the point at any rotation. Polar axis adjusted to my location, and verified ok when I point it at Polaris.

The method I used to fix the home position was with a level. I set everything up on a level tripod. Used a level on the flat inner side of the DEC axis, then turned 90 degrees to home position.  With the counterweight bar extended, I turned the RA axis through 90 deg so I could get a level on the counterweight bar, did the same the other way, and made marks on the RA body.  I thought I could use the dial on the RA axis, but this only screws tight in one position. When the screw is loose the dial spins with the RA - but slips, so doesn't seem accurate.

The issue is when I park the scope in home position, it's miles off from where it should be. When the mount is set up for Polaris, you can physically see the scope is way off to the right. Note, I'm setting up Polaris using the PS Allign app. I have the new type polarscope, so have to turn the RA axis to make sure the scope shows 0 at the top, then position Polaris as shown in the app - and finally turn the RA axis back to home.

Even if I unlock the clutch and align it roughly, when I try to calibrate through ASCOM, all stars are way off.

Is there a reason why there isn't a permenant home mark on the RA like there is on the DEC? Am I missing something fundamental?

Help as usual much appreciated.

Thanks

Andy

 

 

[roblegion]

Andy, what scope are you using?.

[StevieDvd]

You stated:
"When the mount is set up for Polaris, you can physically see the scope is way off to the right."

When you are polar aligned the scope can be in any position, including one that could be called your park position.

As a general rule some refer to the park position as weights pointing north and down and the scope vertical. The alignment and go to software generally accepts that as the park position too, though you can save a custom position as well, such as when you have a dual scope setup.

What I used to do with my HEQ5 was to power it up and set the date, time and position etc. It was already polar aligned being on a pier. Then I would uses Cartes Du Ciel  to send it to a known star, if it was out I'd disengage the clutch and centre the star and synch Cartes Du Ciel  & Eqmod. Then I'd tell Eqmod to park the scope and that was my base park position for the session (I marked my mount to keep a rough note of my park position).

As you would normally rotate the mount to put the scope on, or polar align, it is difficult put it in that exact position manually, so a repeat of the above or 2/3 star alignment tells the system where your scope is pointing and how to adjust it.

If you just use the handset to polar align and then 2/3 star align, check where you scope ends up when you tell it to park. If it not in the conventional park position you may have entered the date/time or location incorrectly.

[adh325]

2 hours ago, roblegion said:

Andy, what scope are you using?.

Hi there, I'm using a SW 100ED, with focal reducer and Canon 700D.

[adh325]

3 hours ago, StevieDvd said:

You stated:
"When the mount is set up for Polaris, you can physically see the scope is way off to the right."

When you are polar aligned the scope can be in any position, including one that could be called your park position.

As a general rule some refer to the park position as weights pointing north and down and the scope vertical. The alignment and go to software generally accepts that as the park position too, though you can save a custom position as well, such as when you have a dual scope setup.

What I used to do with my HEQ5 was to power it up and set the date, time and position etc. It was already polar aligned being on a pier. Then I would uses Cartes Du Ciel  to send it to a known star, if it was out I'd disengage the clutch and centre the star and synch Cartes Du Ciel  & Eqmod. Then I'd tell Eqmod to park the scope and that was my base park position for the session (I marked my mount to keep a rough note of my park position).

As you would normally rotate the mount to put the scope on, or polar align, it is difficult put it in that exact position manually, so a repeat of the above or 2/3 star alignment tells the system where your scope is pointing and how to adjust it.

If you just use the handset to polar align and then 2/3 star align, check where you scope ends up when you tell it to park. If it not in the conventional park position you may have entered the date/time or location incorrectly.

Hi there, thanks for the reply.

Yes, so when the mount is polar aligned I understand the scope could be pointing in any direction. However if the mount has been set-up and levelled off with a bubble level, I'm assuming that if the DEC and RA are in the 'home' position, they should be pretty much perfectly aligned with the mount too. However if I stand in front of the mount its visibly off to the left.

Im wondering if I need to have another go at this. What I don't understand is once you've bubble levelled the weight bar, how can you be 100% certain that when you turn it back to 'weight bar down' you've moved exactly 90 degrees? The dail in my opinion is too unreliable, it seems to move under friction only and slips, rather than being a fixed measurement.

Also wonder if I should double check my stellarium location settings as you've suggested. I did enter them a while ago, but reinstalled so settings might be lost. Could be what's causing the calibration problem.

Thanks,

Andy

[roblegion]

Hi Andy, I'll  give you a check list tomorrow, really sorry can't do it now, got to spend some family time.

[adh325]

2 minutes ago, roblegion said:

Hi Andy, I'll  give you a check list tomorrow, really sorry can't do it now, got to spend some family time.

That would be fantastic - thanks very much!

 

[StevieDvd]

The settings dials on the HEQ5 are notoriously naff and as you say hard to judge the 90 degree rotate back to home, you could double check with a set square and spirit level when it's in the parked position.  If the mount returns to a park position which is slightly out and not the start position you started with it could be location or BST/GMT set wrong.  Note down the settings you have entered and then see if google maps comes up with your location when you enter them (there are online conversions between the different location styles).

 

 

[roblegion]

OK Andy, permission from the mighty one..

Are you using a synscan handset?

 

[8324689]

Im grabbing popcorn for this as a 2016 polar align with ASCOM is exactly what I need to know.

Just got my EQDIR cable and Telrad and Windows on OSX.....

 

A checklist  would be amazing with just the bare essentials what you need to do from scratch

There are so many super polar align tutorials but a no frills 2016 with this technology one would be great!

Many thanks if you can

[roblegion]

OK, I'm sure if I get anything wrong other members will correct me, but this works for me.

1. Your home position can be anywhere, your motors aren't intelligent and can't tell EQMOD where you are pointing (yet).

2. The setting circles on an EQ5 HEQ5 might just as well not be there.

3. If your setting circles were accurate then the little (tiny) circle in the polarscope might mean something.

Start with the tripod. Most have a leg marked N, point it north (with a compass, phone app) . level the tripod.

Add the mount.  Check your level. Set your latitude. You'll have to rotate the scope to open the polarcope port that's ok. If you are correct so far you should be able to see Polaris somewhere in your polarscope.

As I said this is what works for me and is not written in stone. I use an app (computer or phone called Polar Finder), when you open it, input your lat and long( see notes later on lat & long) it will give you a picture like this

This one is a good example because if we look at 00:21 on the example date the Polaris transit is at exactly 9 O'clock.

Go back to your mount and using only the alt and dec bolts (NOT THE SLEW CONTROLS) adjust the setting until polaris sits exactly as you see it in the time view nearest to your current time.

So if your print from Polar Finder looked like the four images above, if you were setting up at 00:21 you would put Polaris at 9 O'clock, if you were setting up at 22 : 51  you would set Polaris to just before 10 O'Clock.

If you have the new type of polarscope this would be your view and Polaris should be positioned with the above diagram where the red and yellow dot is.

Did you notice yet that I didn't mention moving the mount in RA to align the little circle to Polaris or move the "0" to the 12 O'clock position. That's because you don't need to!!!!!!!!

If you look at the images from Polar Finder, now imagine your little circle on the ring, by moving the RA all you are doing is moving the ring to fit your Polaris, you aren't actually moving the mounts alignment.

This is probably more easily demonstrated with the second picture, if you concede that the yellow dot is at 9 O'clock and doesn't move, it matters not where "0" is, the dot will still be at 9 O'clock.

 

 

More to follow.

 

[8324689]

Thanks so much for taking the time to do this. Ill be 100% trying it on my next clear night.

 

Very much appreciated and very clearly explained

[roblegion]

Have you balanced your scope? I'm not going into that here there a wealth of instruction already out there.

Slacken off the clutches (Provided you're balanced). The mount/scope should adopt a natural "scope up, weights down" attitude.

 

NOTE HERE THAT YOUR HOME POSITION WILL NOT NECESSARILY GIVE YOU POLARIS IN THE MIDDLE OF THE TELESCOPE EYEPIECE (and probably won't)

THIS is your home position (aside. I have a white mount and put a sharpie mark at 12 O'clock and 9 O'Clock on the mount so I can check it is going back to PARK correctly). SET AS HOME.

EQMOD doesn't know exactly where your scope is pointing but has a rough idea, (providing you have given it your correct location) Your mount is pointing North and at angle equivalent of your Lattitude (otherwise you wouldn't be seeing Polaris through your finderscope).

I cannot say this often enough.

Make sure your LAT/LONG are in the format your Handset/EQMOD expects. DECIMAL OR DEGREES< MINS< SECONDS.

Similar for date : American handsets may use different date formats to what you are used to.

I am not going to go into different methods for goto's, synching etc for handsets and EQMOD, there are enough tutorials out there.

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If you are happy with your polar alignment issue a goto to a bright star that you recognize or can easily identify,  that isn't more than 45 degrees in any direction from the scopes current position and issue a GOTO. IT will be off but shouldn't be in the next ballpark, if it ois go back to the beginning.

Using the slew controls centre your desired star (and make sure it is the right one) and sync.

Choose another identifiable star within a sensible range (i.e. not having to perform meridian flips) issue a GOTO, using the slew controls, centre and sync.

Now if you are aligned (and should be) issue a GOTO to Polaris. It doesn't look like your scopes in the home position does it.

Its late but: because everything on your mount should be parallel to each other when you see Polaris in your polarscope, you don't have the altitude movement to put it in the eyepiece of your main scope, you would have to do movements in RA and DEc to do so.

This is why when you goto Polaris it looks wrong compared with your HOME PARKED position.

I hope I haven't confused or mislead you, as I say it's getting late and I'll probably end up re -writing this tomorrow.

[Daniel-K]

After you have set polaris through ascom. You can move the RA & DEC Manually. 

Set you weights down and scope pointing at polaris. If you look through your finder you will see polaris. So long as its close you will be fine.

Go backinto ascom clear home position and reset home. Job done. Home set. I do that everytime i set up. Unless you have an obsy and you can park your scope home at the end of each session.

 

 

[Tinker1947]

If you are using a Syscan Handset with firmware 3.37, then why not go the easy route, do a 2 star alignment, when this shows as successful, in the same section a option to do Polar Alignment will show up this will allow any star from a scrolling list to be used and will result in a good PA, do it (park in the home position and turn off the mount then start from scratch each time) 2 or 3 times on different stars, and it will be as good as can be got, if you have a Telrad then it gets so much easier to realign the chosen PA Star but this isn't required.

[AlastairW]

Slightly off the OP issue but I was having problems with my HEQ constantly slewing during a two star alignment, which was remedied by performing a synscan firmware update. When reading up on the issue I was experiencing I remember reading that people were experiencing ASCOM/park/home issues with v 3.37 so it might be worth trying a firmware upgrade on the handset.

[8324689]

1 hour ago, Tinker1947 said:

If you are using a Syscan Handset with firmware 3.37, then why not go the easy route, do a 2 star alignment, when this shows as successful, in the same section a option to do Polar Alignment will show up this will allow any star from a scrolling list to be used and will result in a good PA, do it (park in the home position and turn off the mount then start from scratch each time) 2 or 3 times on different stars, and it will be as good as can be got, if you have a Telrad then it gets so much easier to realign the chosen PA Star but this isn't required.

Aha! Thank you

I head read this months ago an forgot about it. OK will try that 

I do have an issue upgrading the handset which Ill address in another thread.

Hope I didnt inadvertently change the subject !

 

Thanks for all 

 

 

[dph1nm]

3 hours ago, AlastairW said:

Slightly off the OP issue but I was having problems with my HEQ constantly slewing during a two star alignment, which was remedied by performing a synscan firmware update. When reading up on the issue I was experiencing I remember reading that people were experiencing ASCOM/park/home issues with v 3.37 so it might be worth trying a firmware upgrade on the handset.

I think 3.37 is the latest v3 firmware. It was 3.36 that had the start from park bug.

NigelM

[adh325]

23 hours ago, roblegion said:

OK Andy, permission from the mighty one..

Are you using a synscan handset?

 

Rob - you are a saint.  Thanks so much for putting this together.  It answers so many questions.

I'll be going through this method over the weekend, but already suspect it will solve most of my issues.

I started out using a synscan which was a breeze, but now use EQMOD, which has introduced a few complications.

Will let you know how I get on. 

Cheers,

Andy