EQ6/EQMOD alignment problems

[TheCrazedLog]

Hi all:

Mucking around with my EQ6/EQMOD with Stellarium + StellariumScope. The scope is somewhat accurate in one part of the sky (eg around Orion it will be fairly accurate). Tell it to go to another part of the sky and its off by a bit.

Does this mean my (laughable) polar alignment is out? Or that I'm just drunk when I try the align. Or both.

Ta

Anthony

[madwayne]

Hi Anthony

My first thought here is that you are doing a 1 star alignment. On say Rigel and then slewing to say M42? That should be pretty close if not spot on. If you are using only a 1 star and then going a fair distance away from Orion I would anticipate that would be a fair way out. Try the N Star alignment in EQMOD and use at least three bright stars with one on the opposite side of the meridian to the other 2. Try and build as big a triangle in the sky as you can, of course the more stars you have in your N star alignment the better. What I used to do before plate solving, which is a new post altoghter, was slew, centre and synch to a bright star for each new object. The bright star is the brightest one nearest the object you are hunting down. For example you have found Rigil and M42 now you want to slew to Eta Carina, pick Canopus in Stellarium (with your N star alignment checked) synch that into your N star alignment database once centred and then slew to NGC3372 and it should be pretty much smack bang in the centre every time. You could do the same with Sirius and M46 and M47.

I hope that helps. Please give it a go and report back.

Clear skies.

Wayne

[TheCrazedLog]

I should have mentioned I'm actually doing an N-Star align, usually something in the region of 5 stars. However it is entirely possible that I'm missing a step somewhere... does anyone know of a good guide for StellariumScope + EQMod?

[lookus]

i use the exact same set-up and my stars are dead centre all night in all parts of the sky with a 2500mm mak.

makes sure you clear syn data and align data before doing your star alignments. then do multiple star alignments and sync in stellarium.

[madwayne]

Hi again Anthony

Do you have the correct site information set in EQMOD? Launch EQMOD click on the setup expand button and site information is there in the middle pain of the window at the top. It would also pay to check your site information in Stellarium as well.

It might also pay to reset your align data as you may have some old ones in there corrupting your new ones, particularly if you do not setup in the exact same spot night after night.

We will get to the bottom of it as EQMOD and Stellarium, in my opinion, are great pieces of software and at the right price and are usually pretty easy to use.

Wayne

[TheCrazedLog]

Site information is correct, I plug my GPS in there and tell it to sort itself out.

I'm quite sure its something I'm doing wrong, just not sure what. Its possible I'm picking up the wrong stars for aligning (misidentifying them) which would throw it out, but I don't think I am.

Polar alignment is done by setting the thing pointing to south as best I can, then adjusting the axis to read my lattitude... is this enough?

As for Stellarium and EQMod, definately great pieces of software. I picked up Voyager for 1 cent and still use Stelarrium over it.

Thanks for the help so far, much appricated.

[Benno85]

G'day mate,

I wouldn't trust the latitude scale that's on the mount. Get yourself a cheap protractor, drill a hole dead centre and run a short length of string through it. Then on the other end place a small weight (fishing sinkers are good), then hold it against your counterweight bar and adjust the latitude bolts until the string is in line with your latitude.

Apologies for the vague explanation, I'm at work so can't show you a photo but here's a veeeeeeeeeeery rough Playschool-style drawing of what I mean :D

Cheers,

Ben.

[pmrid]

Hmmm! If you mean you're doing it with a hand-held compass and eyeballing the mount, there are some good opportunities for error to arise.
1. Do you line up on magnetic south or true south (allowing for your local magnetic variation)? The difference can be 10-12 degrees or so.
2. DO you use a hand-held compass. These are not the most accurate;
3. Although ASCOM/EQMOD and the various routines in it will help, there is nothing to beat a good polar alignment to begin with.
May I suggest you consider doing a drift alignment and getting your polar alignment spot on then clear all sync and align data in EQMOD and start again. See what has been said earlier about choosing and syncing some good stars well separated.
Peter

[TheCrazedLog]

*sigh*. You know... I'm studying to be a pilot, I've done mapping courses in the RFS, and I had completely forgotton about magnetic variation.

I'd imagine that would be a lot of the problem. Benno I know what you mean, but I do happen to have a magnetic inclinometer so I'll go with that :D

Drift alignment you say? Hmm... not sure what that is, but 10 minutes reading on google should get me moving in the right direction. Thanks for suggestions so far!

Anthony

[OzRob]

Maybe this article will help: Basics of Drift Alignment / Polar Alignment (http://www.iceinspace.com.au/63-405-0-0-1-0.html)

[pvelez]

I wish it only took 10 minutes to learn how to drift align.

Save yourself some grief and use Alignmaster instead:

http://www.alignmaster.de/

It works a treat. The only trick with EQMOD is that you connect with EQMOD, change the alignment/sync mode to dialog based and then run Alignmaster. It saves me heaps of time - Just by plonking the EQ6 down in the yard with a very rough polar alignment (with handheld compass), I can get reasonably good alignment in 15 minutes and excellent alignment in 20 - 30 minutes.

Pete

[lookus]

you rough ppolar alignment is almost surely more error than can be accommodated within eq mod. you should make this more accurate.

if you want to learn drift alignment( and i would highly recommend it) then try this simulator. it taught me how to drift align very quickly with no issues whatsoever. go to this page and then follow the link to the drift alignment simulator. an excellent site.

http://www.petesastrophotography.com/


that said once you know how to do it, alignmaster is fantastic. i tried it for the first time 2 weeks ago and it was an absolute marvel!!

i must iterate it is important to clear the sync and align data in eq mod before doing any star alignments.

good luck. eq mod is a great tool. hope you can get it to work.

[bmitchell82]

I think i really have to get in and do my quick and dirty polar alignment into the articles secion.

Ive come to the idea that do a quick polar alignment (using a 1 star goto, then aligning the star into the ep without use of the hand paddle) to be almost dead accurate and everytime will have the octans sitting in my polar scope with only minimal movement required to get it aligned that being said my polar scope is dead on how do i know? its good for 3 min photos unguided.! so im realitively sure its spot on.

Don't waste your time going all over the sky doing syncs. just get your polar alignment pretty much on the money, then go to where you want to image, and well sync on 2 or 3 stars around the area. In my experience this will land the object of interest dead in the middle of my canon 40d every time!

If your wanting to to many objects in a night, well thats easy too. find a nice bright star around that area to which there is always a bright star somewhere near by sync on that then off to your target, as you go though the night your sync history will grow and you will more often come closer and closer to the target. so instead of looking all over the sky for things to form that perfect triangle just use your goto and the power of EQmod the way it was ment to be! :)

[pvelez]

So to make sure I've got this right - you do a 1 star alignment and if the alignment is out, you move your mount till its spot on and away you go - do I have that right?

Pete

[bmitchell82]

thats what i do and it hasn't failed me yet. just make sure you move the mount by hand loosen off your RA and Dec adjustments and physically move it by hand i do it with 25kgs of 10" and astro kit plus the 25kgs of counter weight with no problems so don't be scared. To make the process quicker i have made a laser pointer bracket that mounts to my finder so i can virtually get it in the middle of the ep without even looking.!

[pvelez]

Cool - I'll give it a whirl. I've tried it a few times but as part of a n-star alignment and sometimes I end up with odd results

Pete

[mldee]

I'm confused. Do you mean unlock the RA and DEC clutches and move the scope assembly to centre the star, or do you mean loosen the mount-to-pier attachments and move the basic mount (Az and El) to centre the star?

The reason I ask is I thought it was really necessary to have the basic mount correct in Az and El as part of a drift alignment.

And for what it's worth, Pete, after getting the basic mount settings right, then resetting the sync and align data, all became well, including the Park position.

[allan gould]

I regularly use alignmaster and in 10 minutes I can have almost perfect polar alignment that guiding will easily correct. But having said that, learn to manually polar align as once you have mastered that then all other procedures become easier.
Learn the basics as there are no short cuts and they will stand you in good stead when all you have is a manual setup when you batteries go flat and your alone in the dark.

[Zaps]

If you always set up in the exact same place, try the solar noon generator on this site to find True South at your observing site.

http://www.solar-noon.com/

Place a long stick in the ground where your tripod normally stands, then, at the exact moment of solar noon, put another stick or marker at the very tip of the first stick's shadow. You now have a True North-South line.

[lacad01]

Alt & Az... a lot of time is saved if you can point true south based on local variation and set the physical lattitude/alt with either an inclinometer or protractor. Do the 1 star align but adjust the Alt / Az physically to centre the star in the EP. My understanding is that this is also required in a drift align, you're adjusting the alt / az physically.

[mldee]

Thanks for the reply, Alt Az is what I thought. I must admit that all my goto problems, including park, went away after I did a couple of drift alignments and got the hang of that.

Small secondary comment for Anthony, Pete and anyone else, is that once you've got the drift alignment tracking well, then you have to get the scope mount section set up as Adam says, so that the scope itself is pointing at the SCP when the mount is parked there.

I glued small (4cm) plastic spririt level tubes on the scope mounting plate (the vixen or Losmandy) and on the EQ6 housing. These verify the RA and DEC for the plate are correct when parked. Use the clutches to correct any error. You don't want the scope pointing off a few degees after the mount has been drift aligned.

After all that, reset the sync data and reset the align data to show correct park position, which it should do itself, based on your eqmod site coordinate data. You're now ready to unpark and do your star alignment as described by others above.

Sorry to clog up the thread a bit, just passing on my similar newby experiences in getting a good goto with eqmod and an eq6.