PDA

View Full Version here: : EQ6Pro South Polar aligning


leinad
03-06-2008, 03:43 PM
I know this may have been asked a hundred times; but I just wanted to check as the SCP is just below my roof line and using the polar finder doesnt become as useful as intended.

My understanding is that I point the mount roughly south compensating for magnetic declination which would be roughly 184degrees? for Perth.
Then set latitude on mount to latitude where I live; which from Geoscience Australia is 32degrees.

then from there add counterweights; and scope and do a balance test horizontally.

then do a 3-star alignment and all should be good for visual use with GOTO.

I have to say the manual is shocking; and at times seems to make absolutely no sense at all.

I saw this post with 'ponders' polar align approach ; and thought this may help apply to me.
http://www.iceinspace.com.au/forum/showthread.php?t=32214&highlight=magnetic+declination

can the polar scope though be removed from the Eq6Pro without damage to use this method?

Sorry newb here with new mount; and need all the help I can get. :sadeyes:

peter_4059
03-06-2008, 05:47 PM
For visual goto that's what I do. I'm pretty sure you can remove/reinstall the polar scope without damaging it however I haven't tried.

marki
03-06-2008, 06:22 PM
Gday

I also live in Perth and use a HEQ5 pro for visual use. I have found that it is not really necessary to have perfect polar alignment if you just want to do a bit of star gazing. Although my mount is not an EQ6 they both use the same hand controller and are a least similar in construction bar the odd difference. This is what I do which gives me good pointing accuracy for visual use.

1. Setup and level the tripod using a spirit level. The leg with N on it should face due south (use a compass).
2. Mount the head and set the latitude just short of 32 degrees (Perth is about 31 degrees, 55' depending on where you are).
3. Add scope, weights, diagonal, eyepiece etc.
4. Balance the scope in the RA axis first using the weights, then dec axis by moving the scope in the rings until it all balances.
5. Set the Ra and Dec axes to zero so the head is straight up and down and the front of the scope is pointing directly south.
6. Plug in all your bits and pieces and do a three star alignment.

You should now be good to go for visual use with most targets falling in the field of view of a 20 - 30mm eyepiece and reasonable tracking.

If you want to take pictures you will need to be far more accurate then this. The magnetic declination for Perth is 1 degree 44' west moving 0 degrees,2' E each year. If you use a compass, get one with a rotating bezel and this should allow you to make the minor adjustments needed e.g. the head should point 1 degree 44' east of due south (180 degrees). It also pays to use google earth or a map to get your exact location (latitude). Use an electronic level to set the exact lattitude (much better then the scale on the scope) and if alls well you should be pretty close to the pole. As you cannot use your polarscope (they are rubbish anyway) you will need to drift align the scope to get proper alignment which is always best to do even if the polarscope is useful. The South celestial pole is very dim and very difficult to spot from the city through a polarscope anyway. If you want to try to remove the polarscope I know the one on the HEQ5 simply unscrews when turned anti clockwise. Not too sure about the EQ6 though.

Good luck

leinad
03-06-2008, 06:57 PM
Hi Mark,

I'm a little confused on 5)
When setting latitude, is your weight rod facing south?
Are there also any video tutorials around. they sure would be useful.
I'll have to do a thorough google search tonight.

Think I might order a illuminated reticle EP this week also.

marki
03-06-2008, 07:11 PM
G'day again

Yes the weights also point south and should be directly over the leg marked N which should also be pointing due south. Consider the weight bar as the front of the mount. When you install the head the whole lot should point south including the front of your telescope. When you set the lattitude the side with the weights should be higher then the side with the polarscope.

PS: I nearly forgot. If you stand behind the mount (polar scope side) and look toward the front of the mount, the bolts that hold the dovetail in place must be on the right hand side. For some reason the mounts do strange things if you leave them on the left side. It is best to place them here before you attach the telescope.

PPS: I dont know of a site with videos but I just googled this site which has some good info, just substitute south for all references to north. Ignor the photography stuff and concentrate on the visual.

http://www.themcdonalds.net/richard/astro/writings/setupEqPolar.shtml

leinad
03-06-2008, 07:19 PM
Ok thanks Mark, a little confused still.

5. Set the Ra and Dec axes to zero so the head is straight up and down and the front of the scope is pointing directly south.

marki
03-06-2008, 07:31 PM
Go back to my last post, I have added a link which should give you the answers you are after. Good pics too :)

leinad
03-06-2008, 07:56 PM
Thanks Mark :thumbsup:

bojan
03-06-2008, 08:18 PM
Re polar scope... anyone has one with spare reticle for our hemisphere only ? (BTW, it is easy to remove, just unscrew it. Be careful not to bend the scale, it is very fragile (thin aluminium)).
Mine is universal, clogged with un-necessary markings which makes recognising the Octans asterism quite hard, especially in light polluted areas...

White Rabbit
03-06-2008, 09:31 PM
Hi

I'm fairly new to this as well and have the HEQ5pro. First thing you need to do is get a decent inclinometer, dont trust the scales on the scope because they are out, crazy but true. I got a really good one from bunnings it cost me $40 but it fits perfectly on the polar scope shaft, and from what I can tell is very accurate. http://elraco.com.au/product_info.php?cPath=37_502&products_id=7738&osCsid=0fe85ffd6d8bd1202a9a6ecf8f09 e572
Another thing I found is that both compasses that I have arnt very good either and my readings were always out, unbeknown to me. Basically take what your instruments are telling you with a pinch of salt.

I know that you dont need to drift align for visual but there no better kick than coming back to your scope in 20 min and the star is still in the center.

Check this site out for a really good explination on drift alignment, but the best thing about this site is that it has a simulator you can practice on. http://www.petesastrophotography.com
Scroll down to the tutorial section and look for drift align.

One thing that had me beat with drift alignment figuring out where the intersection of the Meridian and the celestial equator. I used Starry night to give me the altitude for my location (64 deg for sydney). Then I adjusted using the tutorial it gave you up there.
I cant tell you what a pleasure it is to have a mount that is accurate, before I figured out how to drift align my goto's were never very accurate and I would get alot of failed alignments with 3star align.

marki
03-06-2008, 11:28 PM
You are right about drift aligning (love the simulator by the way) its the best way to go but it can be a bit time consuming especially if you are new to astronomy or like to socialise whist you observe as I do (oops one drink too many and my brains not working properly :D).

To get around this I have placed a concrete pad in my back yard which is reasonably level (too much ethanol again) and carfully marked out the north/south and east/west axes on top of the pad allowing for magnetic declination. All I do now is cart the stuff outside, line the tripod up on the lines, level and square everything up and do my 3 star allignment.

This works well and on sunday night I put Jupiter in the centre of the eyepiece at about 9.00pm. I went inside and waited for it to rise above the trees and when I went out a couple of hours later it was still near the centre only showing minor drift (26mm eyepiece on meade 80ED @ F6). It works with the LX200R as well although the process is a bit more complex when setting it up on a wedge as well as being a whole lot more physical (bloody thing weighs a tonne). I usually need a rest (or a hernia operation) after lugging the thing outside and I really really need an observatory :(. Needless to say I use the ED80 or ETX 125 a lot more than the LX200.

I also bought a nice digital level from my local surveyors outlet. It was a bit pricey but it reads very accurately and can be pre-set to any fraction of a degree. When you approach the set angle it beeps at you at an increasing rate until it becomes a solid sound. This makes it easy as you do not need to look at it and it gives different tones depending on whether you need to go up or down. I consider it an essential tool when setting up and never place any faith in the scales or bubble levels supplied with the mounts.

White Rabbit
04-06-2008, 07:05 AM
One thing I find a real pain with these mounts is that you cant really level the mount with the head on it and taking the head off everytime is a huge pain in the @#%#. Has anyone come up with a work around for this?

Zuts
04-06-2008, 08:00 AM
I level with the EQ head on, it's really not a problem. If you dont want to do this then get a spirit level and level the tripod before putting the head on.

Paul

bojan
04-06-2008, 08:22 AM
I replaced the original bubble level with more sensitive one (~20 arcsec).
This gives me enough consistency for altitude, so the only thing left is azimuth - this is taken care of by compass mounted on a long (1m) aluminium arm. Then I refine with polar scope (if I can see the Octans stars at all) . And the ultimate level of alignment accuracy is drift method after previous has been done (if and when I have time for it)

TrevorW
06-06-2008, 11:36 AM
As far as I am aware true South for Perth is around 178 degrees (178.66)

Easy way to align your scope is make a perfectly angled (90) T piece the dimensions of the tripod legs spread fully tensioned. Make the T piece long end a point put a nail as few inches below the point dead centre of the timber. Place the T piece on the ground point the long end south using the compass to find true South sighting with the nail then align the legs with the T piece points.

Level the head using the bubble or a plumb bold aligned vertically with the T piece.

marki
06-06-2008, 05:54 PM
What a great idea. I usually set up in the same spot so I have marked it all out on a concrete pad but I often run astronomy nights with the kids I teach at school and I can see your method being very useful (now where did I put that mig welder...). Your true south bearing is about right at 178 degrees (being a science teacher I always go about it the hard way e.g. 1 degree 44" E of due south but hey you can never get lost if you start from first principles :). My reference of 180 was to due south on the comapass not for correction for the mag dec). I use the site below to find out magnetic declination.

http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp

TrevorW
09-06-2008, 03:52 PM
Mark where abouts in Perth do you teach.

I use wood for the T piece as it doesn't affect the compass. Your link site is where I got my bearings from as well.

Likewise I have marked the spots where I set up the tripod at home but my little tool is handy for correcting and trips away.

:thumbsup:

leinad
09-06-2008, 07:52 PM
I picked up one of these from Bunnings on the weekend. :thumbsup:
http://www.empirelevel.com/squares/protractors/

White Rabbit
09-06-2008, 09:32 PM
These are great, they even have a magnetic strip on them so you can attach it to the side of your dob to get your pitch right. It takes a bit of the guess work out of it.

AlexN
09-06-2008, 10:01 PM
I have one for this very purpose. Wack it on the back end of the dob, get alt of a target from starry night, raise the scope to the correct pitch and then guess the azi... i know where N, S, E & W are from my site (roughly..) so i can just scan the rough area till i find the target...

Speeds matters up HEAPS.

I may well be posting in here again within the month asking questions on polar/drift align.

marki
09-06-2008, 10:23 PM
I sent you a PM.