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Old 29-07-2018, 04:23 PM
bluesilver (Peter)
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Setting up GOTO system on Dobsonian

Hi, I have received my 10" SkyWatcher Dobsonian GOTO
I haven't done the star alignment or anything yet, just power it up to see if hand controller works and to test the motors for operation, nothing else.

So this is a very basic new owner / beginner question, done some research but haven't really found the answer unfortunately.

So setting up this GOTO system, this is how i understand it and please correct me if i have it wrong.
Set the telescope up so that it is facing true south, not magnetic south,
Level the base so that it is perfectly level, then level the telescope so that it is perfectly level horizontal,
( is last part needed for the Dobsonian, leveling the telescope itself so that it is laying dead flat horizontal)?
Then after setting time, gps location, setup for a two star alignment, Say Hadar for the first one and Antares for the second one.
Is this all correct so far?

The other question i was interested to find out about was,
Every time i take the telescope outside, ( only about 10 - 20 meters away) do i have to go through the same alignment procedure every time?
I was only just thinking that as even if i do put it back down in the same exact spot every time the telescope wouldn't be accurately setup as just a few mm would throw it out if i am correct?
Or am i just thinking into it too much.

Sorry for the long drag out questions that i am sure are very basic common knowledge, but any information would be greatly appreciated.
Thanks.
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Old 29-07-2018, 04:44 PM
m11 (Mel)
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Hi bluesilver,

I have a skywatcher goto 14inch with the synscan handset and this is my routine. I am sure others will have a different one.

1) Colliminate the scope for the primary and secondary mirror/ensure finderscope or rdf is aligned.
2) Ensure the ground is level - others will level the tube horizontal as well.
3) Power on the scope
4) Enter the latitude/longitude/date/time/GMT settings
5) Begin alignment - 2 star alignment
6) Pick a star and use the motors to go to the 1st alignment star
7) Ensure the star is in the centre of the crosshair eyepiece
8) Pick the second alignment star but as far as away as possible to the direction of the first star and if possible around the same height.
9) The scope will slew to the second star by itself - you will need to do the final adjustments to get it into the eyepiece again.
10) Hit enter in which you should get an alignment sucessful
11) Test if the alignment is good by picking an object from the database - ie Messier (m) or NGC/Tour/Planets.

In testing the alignment I would pick something you have seen before - not an obscure object. Planets/Moon/Bright deep sky objects are always good.

You can use the Park scope function to preserve the alignment. To be honest I don't use it as my location my yard will change a fair bit. You will need to check collimination , I do anyway everytime and its always a bit out.

Hope this helps.

Give us a yell on how you go.

m11
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Old 29-07-2018, 05:04 PM
bluesilver (Peter)
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Hi, Thanks for reply, appreciated.
Sounds like the initial setup is pretty straight forward then, been waiting for a good night to actually get it out to do it.
But i take it i still need to have it setup so that the scope is pointing true south, not magnetic south, or is this not really required?

I can see what you mean by the Park Scope function, in that it remembers it's last spot, if i am understanding it correctly.
I was thinking that when i take it back inside then a day or so later take it back out again, even if i mark where i had it previously it would still be out?
Or just best to do the two star alignment every time i take it out?

Sorry if that all sounds a little confusing.
Appreciate any information.
Thanks.
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Old 29-07-2018, 05:44 PM
Malcolm
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The park function is more for an EQ mount, it's not needed for a dob. You don't need to align the tube, put it down, level it, power up etc. and good to go. A good mod is to fit adjustable feet to the base and use a digital inclinometer for leveling. You will have to fit three hardwood blocks to the base to accept the leg threads. I've found that if its perfectly level it tracks better. I've even done a daytime alignment on a planet and found the tracking to be good all night on other objects. Another good mod is to get a 240v to 12v adapter on eBay and use bullet plugs to wire it so you can revert to a portable battery if there's no power available at the site. Centre of the plug is pos +.
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Old 29-07-2018, 06:08 PM
bluesilver (Peter)
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Thanks again for the reply, appreciated.
So there is no need to point the telescope south or true south?
That makes things easier if that is the case.

Yes, i have been building a portable mounting platform on wheels with breaks and also a adjustable legs.
Been cloudy here every day apart from last night where i got it outside and manually viewed the Moon eclipse, got to see Saturn and Jupiter, have to say very impressed.
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Old 29-07-2018, 07:18 PM
m11 (Mel)
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Hi blue,

Yep , just follow the handset prompts. If you get yiurself to a strange menu, hit esc and then use the arrow keys to select again.

I have never pointed scope in any particular direction to align.

Give me a yell next time you do it. Happy to help out.

I generally always align each time.

Regards,

M11
Quote:
Originally Posted by bluesilver View Post
Hi, Thanks for reply, appreciated.
Sounds like the initial setup is pretty straight forward then, been waiting for a good night to actually get it out to do it.
But i take it i still need to have it setup so that the scope is pointing true south, not magnetic south, or is this not really required?

I can see what you mean by the Park Scope function, in that it remembers it's last spot, if i am understanding it correctly.
I was thinking that when i take it back inside then a day or so later take it back out again, even if i mark where i had it previously it would still be out?
Or just best to do the two star alignment every time i take it out?

Sorry if that all sounds a little confusing.
Appreciate any information.
Thanks.
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Old 29-07-2018, 08:48 PM
bluesilver (Peter)
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Thanks again for the replies and advice, greatly appreciated.
Will try it out next time we get good clear skies here
Sounds like I am just reading into it way too much.
Appreciate all the advice.
Thanks
Peter
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Old 29-07-2018, 10:44 PM
m11 (Mel)
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All good Peter.

Pm me if you have any questions.

M11
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Old 30-07-2018, 07:08 AM
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gaseous (Patrick)
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There's a handy app (for Android at least) called SynscanInit 2.0 - basically gives you all the setup info (coordinates, timezone, dalylight saving, etc), in the order you need to enter them. I find it's quite a useful tool.
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Old 30-07-2018, 07:45 AM
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Allan_L (Allan)
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Quote:
Originally Posted by gaseous View Post
There's a handy app (for Android at least) called SynscanInit 2.0 - basically gives you all the setup info (coordinates, timezone, dalylight saving, etc), in the order you need to enter them. I find it's quite a useful tool.
+ 1 for SynscanInit Free and absolute must have for setup
I point it north at startup, in my opinion, anything that may help is worth trying.

And as for doing the alignment every time, YES, you do have to.
Even if you just accidentally pull the power plug out (its too darn easy to do ) you have to do a FULL start up and alignment again.
This can be very frustrating. So I put some tape over the plug to hold it fast.

My alignment procedure (as advised) is to pick the second star at about 90 degrees from the first, with about a 15degree difference in altitude.
Try to avoid anything near Zenith.

Good viewing, you have a great telescope there!
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Old 30-07-2018, 07:46 AM
TwistedRider (Drew)
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Quote:
Originally Posted by gaseous View Post
There's a handy app (for Android at least) called SynscanInit 2.0 - basically gives you all the setup info (coordinates, timezone, dalylight saving, etc), in the order you need to enter them. I find it's quite a useful tool.

Thanks for that!

Nifty little tool
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Old 30-07-2018, 03:54 PM
bluesilver (Peter)
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Sounds like a good app to have.
Might have to look at that as well.
Still learning the Zones or star names, including Zenith, i am sure i will get going when the skies clear up.
Appreciated.
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Old 30-07-2018, 07:51 PM
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madwayne (Wayne)
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Be careful when entering the date. It is in US format mm/dd/yy particularly important in the first 12 days of the month. Last thing you want your mount thinking it is the 8th January when you're looking for 1st August.

For my 12" I don't get too hung up on level. Set it up on the base pointing near North as Allan suggested. Two star align and it is good to go. My eyepiece of choice, 16mm Nagler, gives me a field a bit under one degree and I generally get my objects in that field. I don't even get too hung up on collimation. The 12" solid tube holds collimation really well and I only check it every now and again unless I've driven away from home then definitely check it.

The main thing is to get it out there and give it a go.

Clear skies.

Wayne
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Old 06-08-2018, 11:16 AM
bluesilver (Peter)
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Hi again,
Finally got to get outside last night to give it a go at setting it up.
Didn't quiet go as well as i was hoping it to.
It is due to myself still being new to the stars i am guessing.
I ended up using the SynscanInit 2.0 program just to make sure i was entering everything in correctly the first time through.
Then first off i though i would do the two star alignment,
I ended up choosing Hadar as the first star being a pointer to the Southerncross, at least i think it was Hadar, then went to choose Antares as the second star.
Scope slew around as i was told, but ended up settling on something that wasn't there, no where even remotely close to Antares, I got thinking that what i thought was Antares was completely something else ( myself being new to the stars)
So, i turned it all off, set it up again and this time thought i would just chose brightest star alignment.
This time i went with Alpha Centauri as it came up first, I hope i am correct in saying it is the first of the Southercross pointers?
Alpha Centauri ( Rigil Kent) then Hadar?
So i chose Alpha Centauri, set it in the centre of the eyepiece and then it came up with a second star to go to, not sure what it was called now, but just pressed enter and let it go.
When it finished, it wasn't lined up with any stars, but out of interest i pressed enter to confirm everything, then told it to go to Mars just to see what happens.
When it finished going to Mars, i found the same thing, not even remotely close to it, way off.
Just wondering what i am doing wrong here,
I am guessing my initial first star alignment is incorrect, but i am 90% sure i am working off Southercross.
Sorry for the long post, But interested to here any thoughts on what i might be doing incorrect.
I wouldn't be able to get out to the stars for a week or so due to work though.
Thanks.
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Old 06-08-2018, 11:37 AM
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Allan_L (Allan)
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Hi Peter,
Yeah, its important to get the first star name right.
Perhaps you need to get a Southern Hemisphere Planisphere
(mine is like this image).
Or the star map pages of the Ice in Space calendar, or check online like Stellarium (free)

I usually do 2 star alignment, found it easier and more accurate.
Every thing else sounds like you are doing it right.
Did you check the clutches were tightened? Mine used to slip sometimes, especially in the cold!

Good luck with it.

I'd love to come down and help, if you want to go halves in the airfare?
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Old 06-08-2018, 12:17 PM
bluesilver (Peter)
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Yes, i have been playing around with the Southern Hemisphere Planisphere
I could possibly be using it incorrect funny enough.
Just had another look at mine.
I take it that you are suppose to be holding it up above your head while you are looking at the stars, not holding it in your hands then looking up ( sorry about that basic question )
Dose it really matter if the Dobsonian is pointing North or South when the unit is turned on? as i am thinking it would just be using your initial coordinates that you put in to start with then use that against the first star, ( sorry i know that has been cover before, just thought i would ask)

I am sure it is something very simple, I am just going to have to learn more about the stars first i am thinking.
Thanks.
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Old 06-08-2018, 03:57 PM
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gaseous (Patrick)
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I'd suggest outlaying a little more cash and getting Skysafari - you won't have any more "at least I think it was Hadar" moments! Also, depending on when you were setting up, Antares may have been close to zenith, and in my experience dobs don't align or track all that well choosing stars close to zenith.
Having the tube level when you turn on shouldn't matter, but make sure the base is level, and then the two star alignment should be easy. I chose brightest star last week for something different and it gave me the runaround, so I'll be avoiding that one.
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Old 06-08-2018, 05:51 PM
m11 (Mel)
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Hi Peter,

Sorry to hear it didnt work as intended with the goto.

I would use a star program/app like stellarium and confirm you know both alignment stars. Alpha Centauri will look like two yellow stars in an alignment eyepiece. The second star you choose i recommend you know what it is and looks like.

The second slew is usually a bit off and its sometimes hard to work which star is which. Usually you pick the brightest stars in the sky to align against.

Maybe have a telrad/rdf to assist , so you know with the naked eye what the scope is pointed to assist.

Hope it goes well

M11
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Old 06-08-2018, 06:26 PM
Malcolm
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Important that you set the lat and long correctly. Also set the date as month first, then day and year. Time for you is +10 and no daylight saving. Level the base, I have modded mine with adjustable feet from Bunnings and a small spirit level is good enough. A GOTO base must be level to find the objects reasonably accurately. +1 for SkySafari, drop me a line if you have an Android. :-)
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Old 07-08-2018, 06:50 AM
bluesilver (Peter)
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Thanks heaps for the replies.
i will have to give it another go when i can get back out,
I have heard a bit about the SkySafari, seen it on apps store also.
I have had a few times when the Dobsonian did about 1 and 1/2 turns before stopping at a star, was a bit strange.
Looks like all the data inputs are correct, so it is just me.
Might have to look at getting SkySafari.
All practice i guess, a good learning curve though.
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