goto problems

[garethmob]

hey guys, i knew when i got the mount i was going to get problems

the last 2 nights iv been out i tried to do a polar allignment, (which i thought id done properly but im not sure now) (i havent calibrated the scope every instruction n video on the net really confused me:( )

i set the alt at 51

had polaris in the little dot in my polar scope and on mount and on red dot, an then started the 3 star allignment

this is what went wrong, 1st star, was well out, so i moved it with the arrows till it was centre

2nd star still well out but not as much, got it into centre of my eyepeice

3rd star still out, had to use arrows again

pressed done "allignment failed"

now i dont understand would the weight balance cause the inaccuracy? i had my camera on the mount on top of the rings and for balance had to use a heaveyer weight

i did take the camera off rebalanced it and tried again but same problem

any ideas?

[LMC]

I don't know what mount you used, but don't you have to press 'done' or 'enter', after each star?

[cervesca]

Would doubt if it would be the extra weight, provided it was balanced. If you had polaris in the circle on the polarfinder, I think the main tube would be pointing straight at the ncp, a degree off polaris so polaris shouldnt have been cerntred in your telescope eyepiece. I dont know though how having the alignment within one deg of the pole would affect the alignment - it might still work, depending on the field of view of your telescope?

[malc-c]

Try the following:

* Balance the scope by releasing the clutches and moving the weights or tube. Do one axis at a time

Now to polar align the mount

* Set the angle of the mount to approximately the latitude of your observing location

* With the N on the tripod facing North place the mount with the weight bar pointing to the ground in parallel with the tri-pod leg that should also be facing North.

* Turn the mount so that the telescope is also pointing North. This arrangement is the default home position

* Now power up and turn on the Synscan unit. Enter the date, time etc, and just before it goes to the option to do alignment it will give you the position of Polaris as a clock time, eg 07:30

* Now turn off the Synscan unit, release the clutches and rotate the telescope so that you can see through the polar scope and lock the DEC axis

* Rotate the RA axis to position the bubble on the circle in the polar scope is at approx the time given by the handset as if it was the hour hand on a clock, eg in this example midway between 7 and 8 O'Clock

* Lock the RA axis and now use the adjustment bolts on the mount to place Polaris in the bubble.

* Once you've done that, release the clutches and place the scope back into the home position and lock the RA and DEC axis

* Turn on the Synscan unit and run through the set up once again and then do a two star alignment

[garethmob]

malc-c i'll have a go your instructions seem to be easyer to understand:)

the mount is the EQ 3-2

[malc-c]

No problem, it matters not if it's an eq3 or heq5, the principle is still the same

[JamesM]

Just to add to Malcolm clear instructions. Make sure you input todays date MM/DD/YY (American way) and the correct longitude/latitude co-ordinates for your exact location, a mistake easily made if you observe from several sites. Without sounding patronizing, make sure that the scope is positioned in the direction of the CORRECT star chosen and that it is indeed in the centre of the eyepiece. This is always a bit tricky if your sky view is blocked in some way and your forced to choose a less well known star. It is easy to get something wrong as you progress through the long list of things to do (...I've done it several times). I would perform the initial polar alignment without any kit on the mount as the extra weight might put stress on any adjustment that is needed.

Best of luck and let us all know how you get on!

James

[malc-c]

Can I just add to my previous post and James's, in that my instructions assume you have already aligned the polar scope up with the RA axis. There are lots of tutorials on doing this in the daytime with a distant object, but ideally using Polaris as the object is by far the best way. If your polar scope and main scope are not aligned to start with then you'll never get true polar alignment

[ronin]

Pontypridd is 51.6N (51 deg 60 min). You say that polaris was on the little dot of the polar scope, if you mean the centre then polaris should be on the circle around the centre dot. Also make sure polaris is focussed, not out of focus.

When polaris is on the circle, in the right place, then the mount should be pointing along the axis of the earths rotation. Polaris may or may not be in view depending on the FoV of the scope.

Polaris is not on the axis of rotation so you offset polaris by the required amount. The actual position is dependant also on the time and is probably on the polarscope in GMT not BST as we are in. You will have to allow for that.

What did you supply for the longitude?

Should have been either -3.36 or 3.36W, (3 deg 20 min) depending on how the system wants the information.

Date is US format, time zone is 00, maybe -00. Have met a skywatcher that didn't like 00 and had to have it as -00. BST is On/Yes.

[Cornelius Varley]

The correct longitude/latitude for Pontypridd should be inputted into the handset as 003 21W 51 36N.

Peter

[Jiggy 67]

Apart from what everyone else has said, you needto make sure you have the latest update. I recently got a brand new Synscan goto but it was using old software, check here You need the firmware loader and the actual firmware. Print off the instructions (the instructions with your unit maybe out of date) and its quite straight forward

[Jiggy 67]

While we're on the subject, how accurate does polar alignement have to be for goto?? I've read differing views, some say that rough polaralignement for visual viewing is enough. I would have thought that the synscan finds objects as a result of one, two or three star aligignement, the more stars the more accurate and not polar alignement. I've tried to get a definitive answer to this but without success, can anyone give me one??

[MikeP]

Jiggy67,

If you point your mount north-ish using a compass and point it upwards to your latitude using the scale on the mount - it will almost certainly be some way off being properly polar aligned. However, as you speculate, if you then do the three star alignment properly, the go to will work well enough for you to find objects.

Of course, the mount will not track properly ie they will drift out of the field of view, but for visual it will be good enough.

That is my experience any way.

Mike