EQ3 SynScan polar alignment - am I missing something?

[Welrod50]

Hello all

I am yet again looking for a little help or clarification on the EQ3-2 GO TO SynScan mount. Already had a wealth of info from folks here and other online resources and I was confident I was sorted when I stepped out last night to try out the new baby properly.

It may be that all is well, but I'm unsure so here goes....

Printed off Polar Finder chart which, for my latitude had the Polaris 'bubble' at just past the 9 o'clock mark (if one imagines that the polarscope is a clock face).

Weights off, scope off and rotated mount in RA so Polaris is at the bottom. Mount levelled nicely, with north leg facing north. Spent 20 minutes then crawling about on the cold patio shining red torch down the polar scope so I could see the NCP/Polaris markings and after some messing about with latitude and RA adjustment bolts, had Polaris nicely centred in the bubble. All locked up, double checked, scope and weights back on and off to three star alignment. So far so good...

It then took me a further 20 minutes to align three stars (due to some sporadic cloud and the fact that I had not anticipated the SynScan would not allow me to use Vega after I had selected and centred Dubhe and Merak so had to mess about with star chart to find one off the list which the SynScan had shortened greatly for some reason?) I had imagined that I could use any on its list, but not so?! Time (DST selected) date, coordinates - all set properly. I slewed to Dubhe - off by a bit but surprisingly close, Merak - same again, and finally elected to use Caph (when cloud moved off) again, off a bit and centred as per the previous two stars. So to my mind, all set up right. The mount had missed all three stars by a bit each time, but I centred and saved and alignment was successful. Moved off to M13 and guess what - it missed it, placing it just outside the view on my 25mm EP. Just outside, but outside nonetheless.

So my question is this, did the fact it took me a while to assign the 3 alignment stars throw the scope out? I centred M13 in the EP and slewed to Polaris from the star list and it was off, but again not by much but enough to be outside the EP's field of view.

I resolved to restart proceedings from the front of the house and moved the kit there just in time for cloud to completely cover my skies, so that was that.

Anyway I must say I am soundly impressed with the mount and it must be something I did or didn't do, but I am scratching my head as to what. As I say, the only idea I can come up with is the length of time it took me to finalise the 3 stars. But surely the SynScan should compensate once each star is centred and saved??

Clear skies peeps

Scott.

[Welrod50]

Sorry, just to clarify, when Polaris was at the bottom originally, I did rotate the mount in RA first so the bubble was at the 9 o'clock position to match polaris. Don't want anyone to think I got polaris in the bubble whilst it was still at the bottom

Scott

[malc-c]

Scott, the part I think you went wrong was the positioning of polaris.

• Rotate RA until the bubble is at 6 O'clock position
  
• Centre Polaris on the cross in the centre of the polarscope
  
• Use the alt bolts to position Polaris in bubble
  
• If polaris isn't quite in the bubble, release the RA lock and rotate the mount slightly and lock it off again
  
• Then check the Hr position for Polaris, but remember, the "clock face" is in 24 hrs, and with an inverted polarscope 00:00 . 24:00 hrs is at the bottom, so if the Synscan is stating that Polaris is now at 9 hrs since transit then it would be mid way between 9 and 12 if we use the normal 12hr clock notation.
  
• Release the RA lock and rotate the mount around until the bubble is in this position and lock the RA axis.
  
• Now use the alt / az bolts to centre Polaris in the bubble
  

You should now be able to do a two / three star alignment without too much fine tuning

[allcart]

I have only recently taken up astrophotography, and last night was the first time I had actually used a scope for over ten years. I have just been using a dslr on my mount, with a small finder on the hotshoe just to give me direction. I too used polar finder for the first time last night and my drawing showed polaris at the 8'oclock position. i positioned my mount facing north etc, then placed Polaris at the 8'oclock position on the circle in the polarscope to match the drawing. I did not put polaris in the centre......I am using a CG5-GT mount with a ST80 scope and 25mm ep.

Performed the star align. First star selected was off centre so used the buttons on the handset to make adjustments as directedby the handset. Second star off centre, make adjustments as directed by the handset. Calibration star, still slightly off centre so make adjustments. Chose my target of Pliades and slewed round. Still not perfect, but it was in the FOV of the 25mm ep. An hour later I chose Jupiter and slewed around to it. Still not quite centre, but near enough that I only had to nudge the button.

My Nexstar controller and mount are very similar to yours, so the procedures should almost be the same. The only thing I did different to you was maybe the position of Polaris in the polarscope, and having my mount fully laden when I did the polar alignment. Some folks say this makes a difference.

[allcart]

Thats more complicafed than I did it Malc. I'll try your more refined method next time and see if it is better.

[malc-c]

The reason I suggest centering Polaris under the cross hairs in the scope and then using just the alt bolts to move it down to the intersection with the bubble is because you are effectively placing Polaris at a known starting point, ie as it transit the top of its orbit. Obviously whilst there has been a lot of conjecture about the need to have an EQ mount level, for this purpose the mount needs to be level to do this so that the alt bolts don't give an incorrect starting position.

[allcart]

I think I need to get my head around RA and Dec. Up until last night, I have been adjusting the alt screws and rotating the mount with the two knobs in order to centre polaris. Maybe I have been doing it wrong all along. I need to do more reading and get my head sorted. It was only last night that I used a polarfinder drawing to show me where Polaris should be on the circle, and i adjusted the alt screws and rotated the mount to place it at 8'oclock. I didn't release any of the clutches to do this. Does this make any sense.?

[allcart]

I think i've just worked it out. Instead of rotating the RA axis to place the bubble at its correct time, I have just been turning the polar scope in its threads. Probably does the same thing, but would explain why the handset allways tells me to realign the mount to its index marks when I hadn't actually moved the RA and it was still on its mark.

[Welrod50]

Scott, the part I think you went wrong was the positioning of polaris.

• Rotate RA until the bubble is at 6 O'clock position
  
• Centre Polaris on the cross in the centre of the polarscope
  
• Use the alt bolts to position Polaris in bubble
  
• If polaris isn't quite in the bubble, release the RA lock and rotate the mount slightly and lock it off again
  
• Then check the Hr position for Polaris, but remember, the "clock face" is in 24 hrs, and with an inverted polarscope 00:00 . 24:00 hrs is at the bottom, so if the Synscan is stating that Polaris is now at 9 hrs since transit then it would be mid way between 9 and 12 if we use the normal 12hr clock notation.
  
• Release the RA lock and rotate the mount around until the bubble is in this position and lock the RA axis.
  
• Now use the alt / az bolts to centre Polaris in the bubble
  

You should now be able to do a two / three star alignment without too much fine tuning

OK, thanks Malcolm. So to clarify:

I have rotated the RA to position the bubble at the bottom and locked off. I then need to get polaris in the bubble whilst the bubble is still at the bottom. And then, as the polarscope is inverted, the Polar Finder software gives me a position of 9 o'clock for the bubble, so with polaris still at the bottom, I just rotate the RA so the bubble moves around to the 9 o'clock position if the polar scope is seen as a 12 hr clock face. Then use alt/RA bolts to place polaris back in the bubble.

If so, this is what I did last night with the exception that I did not put polaris in the crosshairs first. I started off trying to get polaris in the bubble at 9 o'clock and ignored the crosshairs. I take it this small potential deviation is why the synscan then went awry a bit?!

I take it the fact it took me a short while to align the three stars doesn't matter?

Thanks again (for all input folks)

Scott

[StuW]

If you were originally rotating the polar scope itself, there's a high probability that it won't be aligned with the mount, so you should probably check that before trying again.

Sent from my HTC One X using Tapatalk 2

[Welrod50]

If you were originally rotating the polar scope itself, there's a high probability that it won't be aligned with the mount, so you should probably check that before trying again.

Sent from my HTC One X using Tapatalk 2

The polarscope is secured in the mount from the factory. It only rotates when I rotate the mount in RA. I think I've understood you correctly?

Thanks

Scott.

[cantharis]

As I say, the only idea I can come up with is the length of time it took me to finalise the 3 stars.

That shouldn´t matter - once you have set the clock you can take as long as you like.

[StuW]

The polarscope is secured in the mount from the factory. It only rotates when I rotate the mount in RA. I think I've understood you correctly?

Thanks

Scott.

In that case I misunderstood what you meant, but you should still align the scope to the mount before using the first time as shown here. Sorry if you have already done this.

http://www.togastro.com/ozzzy/psalign.html

Sent from my HTC One X using Tapatalk 2

[Welrod50]

In that case I misunderstood what you meant, but you should still align the scope to the mount before using the first time as shown here. Sorry if you have already done this.

http://www.togastro....zy/psalign.html

Sent from my HTC One X using Tapatalk 2

Yeah, all done already. To be fair I've spent a lot of time this last week aligning everything, setting accurate home position etc as my ultimate aim is long exposure AP of around 60 sec subs (or less) so to stumble somewhat at the last hurdle last night was a little frustrating. Even more so with the research and meticulous planning I put in before actually going out into the darkness. For it then to miss its target after the three star align, was amusingly annoying. If I smoked, the fag would've dropped out of my mouth in a Hollywood movie disbelief type style when it missed M13 after all that aligning

One day, someone will invent a mount that you can use to align three stars from Ursa major or Cassiopeia say and then a fourth calibratory star elsewhere and do away with this silly polar align/north facing/ crawl about on the floor in the dark nonsense

Scott.

[allcart]

Its ok Scott, I think StuW was talking to me. I'll check the link. Cheers StuW.

[StuW]

Scott, I find I get the same thing myself on my HEQ5, although it did get a little better when I started using a better power supply (an old Amateur Radio PSU I forgot I had), maybe something to look into?

[allcart]

Blast it. First major stumbling block on my raod to fine tuning. The Skywatcher polarscope has tiny allen key bolts for centering the reticule. Even my tiniest allen key is too big. They must only be about 1mm .

How frustrating.

[StuW]

You should have got an appropriate allen key with the mount. I know I did.

[cantharis]

You should have got an appropriate allen key with the mount. I know I did.

I am sure I didn´t.

[malc-c]

Guys, have a look on youtube for Astronomyshed. Dion has done some excellent video's on basic set up, from polarscope collimation, to cone error.

http://www.youtube.com/user/astronomyshed?feature=results_main

Once you have the mount and scope perfectly aligned to the polar axis, then polar align. For those with SW mounts EQMod features a utility that will automatically position the mount in RA at the right position for polaris since it's last transit, taking out all the guess work.

[allcart]

Got 2 allan keys with the mount. Both too big.

I reshaped a small screwdriver and it works.

Trouble is I've dropped a screw somehow and can't flippin find it !!!!. it can't have rolled that far for goodness sake. It will only have dropped about 3 feet onto the floor where I was kneeling. Grrrrr!

Found it. Whew.

[allcart]

That was a royal pain in the butt. really do need an Allen key as its very hard to judge how much you are moving a screw when you use the wrong tool for the job.

Its not perfect, but a lot better than it was.

[ianfiat]

Hi

I'm thinking about buying a Skywatcher explorer 150P on the EQ3 pro (synscan) mount, however all this I'm reading about polar alignment is scaring me a little!

I thought the polar alignment was only required for imaging, isn't aligning the mount to North sufficient for visual use?

I'm starting to wonder if the EQ3 pro mount may be a little complicated for me to use (unfortunately my PhD is in chemistry not astronomy!). My reason for wanting a go to mount is to maximise the time I can look at things- I don't want to be spending an hour each session trying to align the mount!

Maybe I'm overreacting, but I just want to ensure that I buy something I can actually use.

[allcart]

Many experienced folks on SGL will tell you that for visual observing all you need to do is a very basic polar alignment. Just level the tripod facing North. Adjust the lattitude to suit your location and put Polaris into the centre of the reticule in the polarscope. Run the star align program on the Synscan handset and your good to go. This takes about ten minutes.

The Synscan will map the sky and take you to wherever you want to go. there are a few other simple steps to do, but its real easy.

It gets a little bit more complicated when you are imaging and using computer software to guide the scope. In order to get the best results for long exposures, everything must be setup more accurately. It gets even more complicated when things won't behave themselves and do what you ask, but there is usually an answer to every problem and all you have to do is ask the questionon on here.

I only bought my first Goto system a few weeks ago and I had it up and running and I was taking photos in a very short time. The photo's were rubbish, but that was down to user error. The mount performed perfectly. Had I actually been using a scope I would have been well pleased.

Get your scope Ian and have fun.

[BargeGazer]

Don't worry. For visual a very quick alignment is all you need using compass then do a 3 star align (5 mins after the first trial) and then just tell it where to go. (Assuming you get goto)

Once you understand the geometry of the mount all becomes very easy.

Precision settings for imageing may be a different thing though, I am still visual and webcam.

The EQ3 is good for its relative portability. If that not an issue then think about the EQ5 or 6. Not easier to set up just future proof. But more hard earned money!

David