Sent: Tuesday, June 22, 1999 12:18:51 From: email@example.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 compass). 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 earlier. 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. Enjoy 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) Yes. 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 Jeff 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' http://members.aol.com/OptiquesJN
Subject: Tip For Autostar Assistance in Achieving Polar Alignment Sent: Saturday, December 11, 1999 09:16:09 From: firstname.lastname@example.org (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, email@example.com
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