Last updated: 11 December 1999

ETX and Autostar Alignment Tips

Sent:	Tuesday, June 22, 1999 12:18:51
From:	andy.williams@mcmail.com (Andy.Williams)
Alignment Procedures for the ETX

Polar Alignment
The Home Position
The Home position is where you wind the ETX in RA Anti-clockwise until
it hits the anticlockwise stop. You then unwind Clockwise until the
first fork (usually the one with Dec setting circle) is over the
computer control panel, This is the polar home position! The Hand
controller refers you to the Manual but the pamphlet you get doesnt
mention any of the polar methods available.

Alignment Modes
There are 6 different methods.
1,Alt/Az Easy
2,Alt/Az 1 Star
3,Alt/Az 2 Stars
4,Polar Easy
5,Polar 1 Star
6,Polar 2 Stars

Preferentially I use Polar 1 Star (I have a south-ish facing garden and
cant see below 15 degrees for trees).

Switching on the Autostar
This is what happens and what you need to do. The scope is inclined
either using table top legs or a tripod to 90 your latitude from
vertical (I live at 54 and incline by 36) and positioned with a compass
such that it is oriented towards magnetic north (I use a silva 7

I found the length of the leg for the table top legs by setting the
scope Dec protractor to 36 degrees and used a spirit level along the top
of the OTA (Optical Tube Assembly) until the leg was extended enough to
make the OTA level.

The OTA is then swung in Dec to 90 degrees which should give approximate
polar alignment to Polaris. Most Important Dont forget to lock both RA
and Dec. I keep forgetting and wonder why all the motor noise isnt
moving the scope.

Switch the Autostar computer on.

Read the warning, press 5.  Enter all the guff time date etc

The light dims with the Align Menu option visible.

Cursor down to 1 Star

Press Enter

The scope refers you to the manual (which you didnt get !) and asks if
the scope is in the Polar Home Position. It is because you did all this

Press Enter

The Scope slews to a more exact Polaris alignment, bringing Polaris into
the finder and hopefully into the centre of the 26mm eyepiece. Drive the
scope using the keys to a best position on Polaris.

Press Enter.

The scope now slews to the one star. This is never convenient for the
trees etc. You over-ride this by pressing the Down arrow (or Up). 
This stops the scope. Dont press enter when it says  Press ENTER
instead press the down arrow to get at the next star. The Autostar finds
another star and begins to slew to that. You play this cat and mouse
slew, stop, select, game until you find a star which is visible and that
you know, for me this Vega at 11.00pm BST June which is nicely east of
south and straight down my garden.

The scope now slews until it is pointing straight at Vega, If you took
care with inclining the scope and pointing it north Vega will be spot
on. Use the slew keys to bring it centre on in the 26 mm eyepiece.

Press Enter.

You are now tracking in RA and Dec

One last tip when driving the scope to objects it isnt enough to have
the object on line 2 of the display you must press Enter before you
press Go to. I have had the scope slew away driving itself hard against
the stops looking for Vega when I have just used it to align the scope.
It once went to Altair from Vega via the pole star, It never got that
far because I'm sick of the smell of burning clutchs whilst it drives
against the stops.


Andy Williams

Subject:	 Autostar
Sent:	Friday, June 25, 1999 7:36:31
From:	GregoryV@EJBell.com (Vann, Gregory)
I was frustrated with Autostar the first two times I used it but I like
it much better now after about 5 tries. You can't beat it for the price.
I am rather new to astronomy (well, I have taken it up again after 20
years off). Here are the tips I learned the hard way with Autostar.
1. Read the directions (such as they are).
2. Make sure the finder scope is well aligned.
3. Train the drives.
4. Make sure you start out exactly pointed north. 
   A compass is a must for me.
5. After you do the two star or easy alignment go to an object easy to
   find (I used Venus once) and center it in the scope and synchronize.
   The more you synchronize the better Autostar seems to work for me.

Thanks for the web site. It has been a godsend.
Mike here: When using a compass it is important to correct for local "magnetic variation" as Magnetic North does not usually correspond to True North.
Subject:	 Autostar accuracy
Sent:	Friday, June 25, 1999 9:17:30
From:	OptiquesJeff@worldnet.att.net (Jeffrey Nutkowitz)
Below is a copy of some email I sent in reply to some Autostar questions
I was asked. It may be of help to others:

> Subject: Autostar Accuracy
> Hello Jeff,
> I also have an Autostar with original software but my accuracy is
> not as good as
> yours and I would like to improve it.  Basically, my Autostar
> will put things in
> the field of the finder but rarely in the 26mm eyepiece (in fact
> never so far).
> I am GOTOing to bright objects so that I can easily determine
> pointing accuracy.
> I upgraded my batteries from AA alkaline to AA Lithium (rated for
> full power at
> -40F) and this has given me reliable battery power in the field where the
> alkaline batteries tended to lose power at lower temps.
> I bought an Orion 12mm reticle Plossl eyepiece and can now train
> the drive to
> within the accuracy of a single motor step so I know my drive is
> accurately
> trained.

Just double check your training, and use a DISTANT terrestrial object,
not a stellar one. Also, you are doing both axis, right? The
instructions are a bit confusing as far as the procedure goes, and it
may be very easy to overlook important parts or be fooled into thinking
it is done, when in fact only half of the steps get done, but twice. I
only used the 26mm SP ep, and did the procedure twice, on a radio tower
light off in the distance. By all rights, my drive training could be
classified as less accurate than any done with a reticle ep, but I
believe I did it carefully and accurately. It does, however, sound as if
you do know what you are doing, so the only thing I can think of that
may have an effect is whether you used a terrestrial or a stellar
object. Since the stellar object is moving, it will mess up the training
procedure. Also, doing the initial Motor Calibration (I think that is
what is called) function again, before doing the Training, may help.

> I reading WWW and newsgroup posts such as yours, I have learned that the
> Autostar is very sensitive to setup errors.  I know I have to
> level the ETX but
> can I use a bubble level on the base or must I level each axis
> independently?

I use a couple of cheap bubble levels that are contained in a small,
hexagonal aluminum tubes (about 4" long, 3/8" dia, and very lightweight
and portable). They are not that accurate either, but I cross check them
against each other. I level the scope BASE itself, after mounting it on
my tripod/head combo. The tripod has its own bubble level, and while the
head moves in all directions, I try to level the pod first anyway. Then
I mount the scope on the tripod head. Next, I set the scope and its base
in the home position (cc to stop, clockwise until the dec scale fork arm
is over the control panel. Next I roughly aim the whole unit to true
north. THEN I use the bubble levels to level the scope base as
accurately as I can- up/down and left/right (the two directions the
tripod head can move), and lock the tripod head. Once that is done, I
then lift the optical tube to 40 deg, and gently rotate the scope on its
az axis (the tripod head is locked, but since I did a rough aim to true
north, I should only have to move the scope a tiny bit on its OWN axis
now- I did not lock the scope's az axis yet). I use the North Star to
get the scope aimed to true north- first in the finder and then in the
eyepiece, and then lock the scope's az axis. I then return the optical
tube to the horizontal, 0 deg position, lock the scope's dec/alt axis,
and the scope is now accurately set in the correct home position: OTA
aimed to true north (within one degree, anyway), while the control panel
on the scope base, and the fork arm with the DEC scale above, it are
facing west. Then I do the 2 star easy align.

> Should the OTA be level or at 0 degrees? (Actually it probably
> should be both
> level and at 0 degrees if the alignment is accurate)


How can I
> get the home
> position pointing at true north?

See above detailed account of my use of the north star.

Should I do an one star align
> on Polaris, move
> the tripod to center Polaris (thereby eliminating most setup
> errors in azimuth
> and altitude) and then return the scope to home position and do
> an follow-up
> Easy Align?

I would not bother with this methodology. Any of the easy alignment
procedures need to be done AFTER the scope base is leveled and the scope
set in the home position. Keep in mind that the scope actually does NOT
need to be accurately set to true north or to its 'home position,' but
the base MUST be accurately leveled (this is of course assuming you are
using it in Alt-Az mode. The only difference for Polar mode is that the
scope MUST be accurately polar aligned before anything else, but there
is no practical reason for using Polar mode other than for photo work.
Alt-Az mode is otherwise much easier to deal with and use- no chance of
the scope hitting the base for southerly objects and it is just easier
to make sure it is level as opposed to polar aligned). If the scope is
not accurately set to true north or its correct home position, it is
theoretically still possible to do a good two star easy align. However,
the scope's initial aiming at the first star will be less accurate than
it could be, and you will then feed the scope more information about its
aiming errors as you center the alignment star. I personally feel,
however, that the LESS information (ie correction data) you feed the
computer during this process, the less information it has to process
every time it does a GOTO calculation, and the more likely an accurate
calculation will result. In reality, again, the correction information
you feed the computer when you center the alignment stars is nothing
more than a fixed value once it is entered, and there is almost ALWAYS
some value, some correction, some centering of the alignment stars to be
done. I have basically never had an alignment star show up dead center
to begin with, but I just believe that the more accurate the original
home position setting is, and the less centering you have to do on the
alignment stars, the more accurate the computer's GOTO calculations are
likely to be...STRICTLY a personal feeling.

> Anyway I have more questions than answers regarding how to
> maximize the accuracy
> of my Autostar and ETX.  Maybe you could share some details of
> your ETX Autostar
> setup procedures.

(see above)

If all this still does not result in getting at least 80% of the targets
within the field of the 26mm SP ep, perhaps there is a quality control
issue involved. Contact Meade, OR it may be to your advantage to check
Scopetronix's ETX90EC drive tuneup page. If you are not worried about
warranties or are not of the feint of heart, and you are willing to
disassemble your scope and tweak its drive mechanisms per the web site
procedures, it may make a difference in your results (I have not done so
myself- my unit is factory stock). Or you may try updating your Autostar
to the latest Ver 1.1m. I have NOT done so yet, so it is not likely to
make a major improvement in yours or anyone else's results, ALL OTHER
things being equal. Supposedly the newer version does track better, has
several bug fixes (most related to Polar mode operation), and much
better Tour lists.

More tips: Though it is not really recommended, as it messes up
alignment/aiming for other areas of the sky, if you are observing a lot
of objects in the same general area, GOTO an easy/bright one, center it
in the eyepiece, and the do the SYNCH function. When I do this, it
invariably puts any other objects in the vicinity nearly dead center
when I GOTO them. Well, almost invariably, usually over 90% are nearly
DEAD CENTER. There still seems to be almost always one that misses
completely though, but hey, getting 90% of all other targets ANYWHERE in
the eyepiece is MORE than acceptable to me.

Hope this helps. Really, I am surprised that there is such a variance in
the results people are getting from this thing. Mine works well,
surprisingly so even, considering how much less it costs than anything
previously available like it. On the other hand, that is all I expect it
to do- work well, and it does. It is a very pleasant thing to see how
well it does with the many objects I have observed with it over the past
5 months I've had it. Very few of them required any extra effort on my
part to locate.

Take care 

PS You are welcome to pass any or all of this info along to anyone/anyplace
you wish.

Jeffrey Nutkowitz/Optiques Classic Photographic Imagery
Freelance Outdoor and Nature Photography Emphasizing a 'Sense of Place'

Subject:	 Tip For Autostar Assistance in Achieving Polar Alignment
Sent:	Saturday, December 11, 1999 09:16:09
From:	fgoldner@worldnet.att.net (Frank Goldner)
Recently, I wanted to do some prime focus photography of objects high in
the sky -- precluded on an ETX aligned in the Al-Az mount mode.  So, I
finally had to pursue polar alignment.  In doing this I realized that
the Autostar has the capability to assist in a acieving a potentially
more precise 90 degree declination tube position than possible using the
ETX fork mounted declination scale:

-- Carefully put the ETX in the Alt-Az "home" position. The best results
will be achieved if both the scope tube and the base are carefully
levelled (I have found a small "torpedo" type level easier to use than a
bubble level for this purpose, and also use of a "map-reading" compass
with its rectangular plastic base useful for setting the scope to
magnetic north). BTW, as previously noted on this fine site, a map
showing magnetic north corrections for the U.S. is given in the LX
instruction manuals on the Meade site.

-- Initialization of the Autostar in the polar mode, permits reading of
the precise polar altitude position for a given location by pressing the
mode button for two seconds or more, scroling down one screen, and
reading the altitude value (Autostar doesn't know that the scope tube is
not yet pointing to Polaris).

-- At this point, reset the Autostar to the Alt-Az mount mode, turn the
Autostar off and then on, go back to the Alt-Az screen via the mode
button (Alt should now read zero) and raise the tube using the Autostar
up button to 90 degrees altitude. If done right, the scope tube is now
well aligned with the 90 degree declination position of the scope forks
without having had to use the fork declination scale.

-- Finally, manually set the tripod wedge, or head angle setting, to the
correct angular position for polar aligning, re initialize the Autostar
in polar mount mode, seek the north star by adjusting tripod legs as
recommended in the manual and proceed with normal star alignment  (I
have had some problems with one-star method but not with easy or
two-star alignment with my v1.3b Autostar program). Also, the torpedo
level, placed across the back of the fork mounts, prior to raising of
the tube, can be used, via levelling by using left-right Autostar
buttons, to get the tube's vertical motion in a polar aligned plane.

One, theoretically, could also use the Alt-Az mode Autostar to correctly
set the wedge angle, by raising the tube from the Alt-Az home horizontal
setting to the compliment of the polar altitude angle (i.e. 90 degrees
minus the polar altitude) with the Autostar up button, re-leveling the
tube manually by adjusting the wedge, or tripod head angle, and then
using the Autostar to further raise the tube to 90 degree position;
however, I find the simultaneous wedge-setting/horrizontal-tube
determination too cumbersom to effect to really recommend this
additional proceedure -- unless one absolutely wants to avoid reading a
wedge angle scale.

Best Regards,

Frank Goldner, Bethesda Md,  fgoldner@worldnet.att.net

Return to the top of this page.

Go back to the Autostar Information page.

Go back to the ETX Home Page.

Copyright ©1999 Michael L. Weasner / etx@me.com
Submittals are Copyright © 1999 by the Submitter
URL = http://www.weasner.com/etx/autostar/as_align.html