Synscan - HELP!

[adman (Adam)]

I bought my synscan upgrade for my EQ5 last October, and have used it successfully for guiding and tracking without any issues, but whenever I try to do an alignment with it for GOTO, it is way off - WAY off - maybe 15-20 degrees......

Up until now, I have thought it was something that I was doing wrong, but I have been reading a few threads on this forum and others that suggest the handset may be at fault.

However - one thing I cannot get my head around is that if it is the handset, and I am bypassing it using CdC via EQMOD (I am using the cable from the USB-serial converter that plugs into the handset), should it still be an issue?

I tried a few experiments tonight inside to get a feel for what the issue is. The first thing I tried after unparking the mount, was to slew to Antares first with the handset, no PC connection, then with CdC connected via EQMOD. These both gave me the same, way off, position. I tried a star - can't remember which - that should have been just above the horizon, and it gave me 20 degrees below horizon.

I am thinking that I am going to give Ron a call at Sirius Optics, and see what he says.

Any ideas before I do that?

To pre-empt a few:
1. The mount is aligned south with correct latitude set
2. My lat/long is set 27d27m S, 152d 59m E in EQMOD and handset and CdC
3. My time is set to +10.00 hours, and entered in 24hr format
4. clutches are not slipping
5. date is in mm/dd/yyyy format

Cheers
Adam

[adman (Adam)]

Ok - now I am REALLY confused.

I called Ron this morning, and his advice was to spin the mount so that it pointed north instead..... because they had sometimes found that with some mounts this was the only way to get the goto to behave normally...

How is it going to track correctly if the polar axis is not pointing at the SCP around which everything appears to revolve??

Any thoughts/help would be greatly appreciated....

Adam

[bmitchell82 (Brendan)]

if your connecting to a PC, and running the mount though there the hand set does absolutely nothing at all. ive nearly forgot how to use it. Make sure EQMod has the right lat long/time not only CDC because from my eperience with starry nights, it automatically updates information from EQmod. Do you get the same error with the hand paddle only?

[Steffen]

Does he mean pointing it down to the ground?? Because that's where North is. Or pointing it perpendicular to the polar axis?

This sounds bizarre…

Cheers
Steffen.

[ozstronomer (Geoff)]

Adam,

When I do a 3 star alignment for my HEQ5, sometimes the mount is up to 5deg from the selected alignment star. I just move it onto the star, do this for the three stars then get Successful Alignment. I can always find the object in the FOV after each slew.

I can have problems if I park the scope and then use it directly from the unparked position. It is far more accurate if I re-align each session or after I unpark it.

Hope this helps. Lets have a look at it next time we are at 10 Chain Hill.

Cheers Geoff

[banjo]

The cause of the missalignment I found is due to Magnetic north/south being 11deg different from celestial north / south.
If you get a cheap Compass from Big W ($6) place it on the ground where you intend to set up the HEQ5.
Identify 169deg (this is 11deg east of south)
Set the HEQ5 mount up with the "N" leg facing approximatly 169deg.
Adjust the Declination to your approximate Lat (ie 27deg)
Make sure the mount is reasonably level & give the 2 or 3 star alignment another go.
Make sure each star selected is in the center of the eyepiece
(i firstly use 26mm) then put in a 12mm & recenter, before I accept each star.
This should help with your allignment problems.
let me know how it goes.
Regards.....Banjo.

[adman (Adam)]

I determined true south by using the shadow of a vertical piece of string at solar noon, and I have a line scored into my pavers. I have yet to find a compass that I trust....

[banjo]

The first 2 times I set the mount up I had the exact same issue you are having.
If you get the 169deg direction correct the initial star alignments will be almost perfect.
If however your mount is not quite level the alignment star could be slightly lower or higher than the expacted position that the mount slews to.

[banjo]

If you know magnetic sout is correct , hold your closed fist at arms length & the width is about 10deg , just make the adjustment east 1 fist width.

[adman (Adam)]

THanks for the suggestions banjo

the shadow-at-solar-noon method gives you true south, not magnetic south - so I am pretty sure that the mount is aligned and levelled correctly. The slew to the first alignment star is off by 20-30 degrees I would estimate - more than you would expect than if the mount was out of level by a degree or two...

[Manav (Yugant)]

This Sunrise/Sunset Calculator and this website can assist.

[Tandum (Robin)]

You do realise that your first alignment star may well be a long way off. You need to slew and center it in the FOV then press enter on the handset to sync it's position and to move on to the next star. The second alignment star should be a lot closer than the first, so long as you're level and polar aligned.

[mldee (Mike)]

Once you've got your USB cable connected, I'd put the Synscan handbox and software where it belongs; back in it's box, and stick with a PC and EQMOD.

BTW, don't forget to de-select the auto-load points list option in EQMOD until you get a half-decent goto. Then save that list, so you have a reliable set to start with next time.

[adman (Adam)]

Originally Posted by Tandum

You do realise that your first alignment star may well be a long way off. You need to slew and center it in the FOV then press enter on the handset to sync it's position and to move on to the next star. The second alignment star should be a lot closer than the first, so long as you're level and polar aligned.

What do you call a long way off? My first star was Antares - in the ESE around 30 degrees elevation. The scope ended up pointing northeast about 45 degrees elevation. If the scope knows it's at home position, it surely should get closer than that??

I have been through the full alignment process a couple of times, and the subsequent stars don't seem to get any better.

Adam

[Tandum (Robin)]

That sounds wrong. What happens if you align it, park it, switch it off then on again and align again on the same stars. Does it still think the first star is in the other direction? I'm wondering if it's not parking properly. I think you can query it's current location from the handset, maybe check that before and after you turn it off/on. And have you tried a factory settings reset on the handset?

[adman (Adam)]

Yep - I have spent a bit of time making sure that the park position is correct - when you query the scope position alt/az through the handset, it is correct. I have not tried the factory reset as yet though - will give that a try....

I also checked the RA/DEC after that first slew to Antares, and the coords it gave were the same as those in CdC - but thinking about it now, I didn't check alt/az....

Adam

[bmitchell82 (Brendan)]

Adam, it sounds as if you have daylight savings set on or the wrong time, something to that degree. there's a software issue here.

have you tried to park it, then re slew it to the same object and see where it ends back at? if you keep getting repeatable go to's even if its not the right star ect ect, as long as its going back to the same spot, then the mount is working fine.

PM me if you would like some help to make sure that everything is right, even when you think everything might be right sometimes there are things you don't know about that will play havoc.

As for your polar alignment as long as your within say 5 deg on each axis then the most you can be out is up to 10 degrees from the target which is huge and you would know about it.