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Tyson M

Super accurate GOTO Synscan

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Hello,

i have an EQ6 and was just curious how I can go about getting super accurate GOTO alignment.  I am having issues finding smaller targets with my 8" mak because my goto is always off.  So I have to scan around a lot.  Sometimes I find the targets, most times, not sure.

I just started using SynscanInit 2.1 along with SS6 pro as a  visual reference but I am not sure if the app has helped or not (the hour angle seemed off even though it pinged the right GPS). 

I did the alignment procedure (both 3 star and 2 star) three times last night and I was still out by approx 2 degs in elevation and 1 deg in AZ.   This is seriously cutting into my observing time, and objects like planetary nebula and non common double stars are basically impossible to find for me.

Any tips would be most appreciated. 

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This is where you need to use plate solving it makes all the difference.  There is quite a choice of free software that will do this for you.

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Is your mount level and when targeting your first alignment star do you end with right and up directions.

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I would second the plate solving, revolutionised my sessions now, goto target, platesolve, synch to position, no problems.

 

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You are depending on three things: Polar Alignment, Star alignment and cone error.

When you have done the PA, you can estimate how good it was by doing a quick drift alignment procedure.

Then if you do the three star alignment, I think the mount will calculate the cone error and compensate for it in software (it will be stored even with power off). This is a good thing to do if you do not eliminate the cone error mechanically.

(If you are just going to one single position during the session, you can just do a one star alignment on a nearby star, and the goto will be very accurate).

Ragnar

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I've found the more accurate you star align the better your goto's will be.. cone error is a prob if you're viewing the other side of the meridian  which can be manually sorted out  

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12 hours ago, Tyson M said:

super accurate GOTO alignment

No other simple way works better or as quickly than using Platesolving - it tells you where you are and nearly (nothing is perfect) always will get to where you wanted to be AND if required dead centre an object in even the smallest FOV.  

Note it only gets you there what, happens next is outside the design of what Platesolve is for!

BUT it does require a computer !

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7 hours ago, happy-kat said:

Is your mount level and when targeting your first alignment star do you end with right and up directions.

My mount is perfectly level, but no, I wasnt ending my movements to the alignment star in up and right directions :(

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59 minutes ago, Anthonyexmouth said:

+1 for plate solving. It's a game changer. 

 

1 hour ago, stash_old said:

No other simple way works better or as quickly than using Platesolving - it tells you where you are and nearly (nothing is perfect) always will get to where you wanted to be AND if required dead centre an object in even the smallest FOV.  

Note it only gets you there what, happens next is outside the design of what Platesolve is for!

BUT it does require a computer !

Hmmmm it seems platesolving is the way to go.  I carry out a deep cycle battery which can power the mount and computer so perhaps I should look into this.

 

I will buy a 12.5mm reticle eyepiece to align perfectly.  I will end my movements in up and right directions only.   If this doesnt work, I will try to learn platesolving. Problem is , in the extremely cold winter, my laptop will not work- battery drains in like 5 mins.    I am hoping the first two steps will be sufficient.   I also downloaded a new app, polar alignment.  This app shows a different hour angle for polaris than the SynscanInit 2.1 app...........unreal!   Perhaps this was my issue as well.....

 

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I can't see where the OP mentions being an imager so perhaps plate solving isn't the answer?

As I've said before, I find synscan to be robust and forgiving. I set up my EQ6 only very roughly on polar alignment. Just get Polaris anywhere inside the PA reticle of the polar scope and I'm happy. Hour angle? yeah, not!   Mount level? Has no meaning in reality with a GEM though I've heard it argued that a level azimuth plane improves the drift alignment procedure when used.

Then on to 2 or 3 star alignment.  My 1st star is always a billion miles out because I don't use the "home" position so tweak that to center it. Second star always in the field of view, tweak that to center it. 3rd and probably not needed star just refines it further. Bingo! I'm good to go(to).

My GOTO targets are always well within a low power field of view. 

I can't imagine that poor PA correction in the polar alignment process would make GOTO so far off. I suspect there is another issue at play. 

 

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Have you considered power supply as this also makes a big difference ie if cheap version it can introduce error if noisy hence worth ensuring a decent supply with minimal noise and sufficient current. The supplies on Flo website are a great choice as switched to one myself after using a cheap eBay variant that didn’t work out 

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I am not an imager, visual only.  I prefer to not bring out my computer at all costs.    I don't think I have a problem with power but I can easily test that with a multimeter. 

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If you really really want super GoTo, then Platesolving is probably the way to go.

But if you really only want to get quickly to a dim DSO:

GoTo a bright star near your target, centralise it with the handset, and Synch.

Then GoTo your target.

For instance, Vega and M57.

Michael

 

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I’d look to physically reduce cone error; use aN illuminated reticle eyepiece; end with up / right or whatever is appropriate for your mount.

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On 19/10/2019 at 16:34, Tyson M said:

My mount is perfectly level, but no, I wasnt ending my movements to the alignment star in up and right directions :(

I would definitely try ending alignments in the up and right directions, made a huge difference on my CG5, which I was ready to trade in until tried this! Admittedly this is nexstar not synscan, but same principle applies. I only polar align roughly and do a 3 star align and the gotos are within about 1/3 degree on nine out of ten objects. 

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23 hours ago, Tyson M said:

I am not an imager, visual only.  I prefer to not bring out my computer at all costs.    I don't think I have a problem with power but I can easily test that with a multimeter. 

Multimeter ok for voltage and current but won’t be able to detect noise or ripple in supply you’d need an oscilloscope, the noise can affect accuracy hence why worth ensuring a decent supply ( I found this out hence why changed supply) 🙂

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