Re: Help with AP GTO on Parallax 125
Tim Khan
Mike,
Check if the setting on your hand controller is for the proper mount. On the AP mounts you can set up the hand controller for the 400, 600, 900, and 1200 mounts. Choose the correct one for your mount. Remove your shims. Alternate method for Othogonality: Do a star drift alignment, get alignment very accurate, center a star on the same hour as Polaris, calibrate with that star, and slew to 90 degrees Dec and same hour angle, check if setting circles agree with computer. Doing this should prevent a change in RA when slewing, just incase something is wrong with the RA. Insure that you are pointing exactly 90 degrees in dec. If unsure of the Dec, pick a star and manually slew using the mechanical setting circles to 90 degrees. Rotate Mount with RA only. Look using medium to high power through the scope. The stars in the field should rotate perfectly around centered of the field, if not your orthogonality is off, you can shim either ring to bring the orthogonality in. Remember, you must be polar aligned, and be point perfectly 90 degrees Dec. Now slew to a star, like Regulus, recalibrate on the star. Try slewing to other stars to see if it is pointing properly. I hope this helps. Tim --- Mike Mah <mikemah@...> wrote: AP 155 EDFS, AP rings on 16" Parallax Dovetail on__________________________________________________ Do You Yahoo!? Send instant messages & get email alerts with Yahoo! Messenger. http://im.yahoo.com/
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Help with AP GTO on Parallax 125
Mike Mah
AP 155 EDFS, AP rings on 16" Parallax Dovetail on Parallax 125 with
AP GTO. I have had this out several times now and have been unable to get it to point accurately - place and time setup are correct. On calibrating with Polaris, I have used Pollux, but after several iterations, whenever the mount slews back to Pollux, it is always off by a couple of degrees and I have to push the East button to re-center Pollux. When it slews to Polaris, Polaris will be centered. When I slew to another object, I can find it by pressing the East button for the same period of time. I haven't checked for orthogonality using the method in the manual - I don't know which stars straddling the meridian to use and I can't stay up later to use Arcturus as per manual. On spec and assuming a one degree error in orthogonality, I shimmed up the front rings by one quarter inch tonight and it didn't seem to make any difference. Even when I recalibrate on Pollux and then slew to Castor there is still variable error of about half a degree. Any ideas? Mike Mah
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Re: GPS enabled A-P goto mounts
Louis A. Mamakos <louie@...>
Once SA is gone, accuracy will be improved perhaps by one order of
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magnitude to about 10m as compared to about 100m with SA enabled. Of course, if you're not moving, you can average your position and do somewhat better than that. Unless you are moving, GPS won't be of any help in figuring out your orientation. (Well, you can play some games if you have multiple antennas and do relative carrier-phase measurements to figure out your orientation with respect to a satellite, but this is somewhat specialized and expensive.) But even today with SA, knowing where you are within about 100m and what time it is within a couple of hundred nanoseconds ain't too shabby.. louie
The government announced today that the purposeful degradation of the
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Re: Tripod for 400 GTO
Chris Spratt
I don't have the Davis and Sanford aluminum tripod but do use the wooden one and
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this may be more suitable in the long run if you don't get a pier. Marc Zukoff wrote:
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Re: Tripod for 400 GTO
John J. Kasianowicz <surpher@...>
I own and use the wood tripod I bought from A-P. It's a bit heavy (I've
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taken it with me to Curacao though). However, it's a stable platform for my Traveler/AP-400 QMD. I have absolutely no regrets about purchasing it.
I am anxiously awaiting my mount, but am wondering about the Davis
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Tripod for 400 GTO
Marc Zukoff <yooody@...>
I am anxiously awaiting my mount, but am wondering about the Davis
and Sanford aluminum tripod.Is it a good choice or is the wood tripod a better one, or any other suggestions. i am planning on using a 4 inch refractor for now, but hope to also obtain a 5 inch refractor in the next year.
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GPS enabled A-P goto mounts
Paul Wilson <plw@...>
The government announced today that the purposeful degradation of the
GPS (Global Positioning System) signals available to civilian users will end tonight. With selective availability (SA) disabled, accuracy will improve by a noticeable amount. Just as significantly, the accuracy of the time signal will improve as well. Wouldn't it be neat if I could tie my GPS unit to the controller of the A-P mount? At the very least the mount would know right where it's positioned (latitude/longitude) and the exact date and time. It would also know very accurately the direction of true north. As today's press release mentions, there are many improvements to GPS in the works ranging from more satellites to new signals being broadcast. Unless you're a U.S. taxpayer ;-), it's free, and will probably stay that way. Imagine a portable equatorial mount that polar aligns itself! I expect that it will happen sooner than we think. Paul
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Re: Scope balancing question
Larry Denmark <kldenmark@...>
Wow,
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Many to many "not"s in my last message <g>. Since you stated that you can move the 9 lb. counterweight an inch or so before noticing a difference, it implies that moving it 3 or 4 inches will make a noticeable difference... and that's OK. A-P makes great mounts... not sensitive beam-balances <g>. Larry
----- Original Message -----
From: "Larry Denmark" <kldenmark@...> To: <ap-gto@...> Sent: Saturday, April 29, 2000 2:40 PM Subject: Re: [ap-gto] Scope balancing question Hi Paul,stiffness in the 600E... more so than was in my AP400 mount. But I am not certain ifyou are not experiencing a problem because I do not understand the following:(so as to revolve the telescope in a circle around the DEC axis, as you stated) orThey are easy to adjust... let us know if that is the case.
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Re: Scope balancing question
Larry Denmark <kldenmark@...>
Hi Paul,
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The Traveler is light weight and there is a certain amount of inherent stiffness in the 600E... more so than was in my AP400 mount. But I am not certain if you are not experiencing a problem because I do not understand the following: I'm not clear which axis your son had trouble turning. Did he try and rotate the DEC axis by turning the counterweight as though it was a steering wheel (so as to revolve the telescope in a circle around the DEC axis, as you stated) or did he grasp the counterweight and pull or push on the counterweight shaft (so as to move the mount about the RA axis)? And was the traveler seated on the mount at the time (I assume so... but do not know for sure). If he had difficulty turning it about the DEC axis, you probably do not have a problem. If he had trouble revolving around the RA axis, especially if the Traveler was seated opposite the weights, the clutch plates are too tight. They are easy to adjust... let us know if that is the case. Larry E-mail . . . kldenmark@... Web site . . http://home.att.net/~kldenmark/
----- Original Message -----
From: <Paul_Schroeder@...> To: <ap-gto@...> Sent: Saturday, April 29, 2000 1:30 PM Subject: [ap-gto] Scope balancing question AP Traveler) and the bearings on both axes of the 600 are really quite stiff(much, much more so than on my Great Polaris). Even with the clutches fullyaxis. I had my ten year old son try to rotate the dec axis boy simply turning thean exact balance. I can move the 9 lb counterweight an inch or so up or down thethe stiffness of the bearings.one inch on counterweight position be considered sufficiently precise? I'm alsothem), and I'm wondering if this is due to poor balancing.
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Scope balancing question
paul_schroeder@...
Quick question. I have tried to be very careful in balancing my one month old
600 prior to each use, but I might be doing something wrong. The challenge I'm having is that the instrument I'm using is fairly light (an AP Traveler) and the bearings on both axes of the 600 are really quite stiff (much, much more so than on my Great Polaris). Even with the clutches fully disengaged, it takes a fair amount of force to rotate the mount on either axis. I had my ten year old son try to rotate the dec axis by simply turning the counterweight shaft and he had to try pretty hard to do it with only one hand. Given that there's a lot of resistance to rotation, I'm not sure I've gotten an exact balance. I can move the 9 lb counterweight an inch or so up or down the shaft with no real noticeable difference in the balance point, mainly due to the stiffness of the bearings. Is this level of "stiffness" in the bearings typical? Should plus or minus one inch on counterweight position be considered sufficiently precise? I'm also having problems with the clutches slipping (I don't want to over-tighten them), and I'm wondering if this is due to poor balancing. Any suggestions would be appreciated! Best regards, Paul Schroeder
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Re: Slewing sound frequency
howard lazarus <lazhow@...>
Hi Brian;
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I have had the 600 GTO for close to two years now getting mine in Oct 19998. The sound on occasion does change and at times it depends on the balancing of the weights or the EP you are using. The slight change in noise is there but of absolute no importance and will not effect the accuraqncy of the slew. SO ENJOY! Howard Lazarus
----- Original Message -----
From: Brian Herbst <dbherbst@...> To: <ap-gto@...> Sent: Thursday, April 27, 2000 7:30 PM Subject: [ap-gto] Slewing sound frequency Hello,
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Good polar calibration stars?
Brian Herbst <dbherbst@...>
Hello,
First, let me apologize to members of this group who are south of the equator... When doing the 'N Polar Calibrate' is there a list of good stars to use for this exercise anywhere? The AP manual says to pick a star that is in the eastern or western sky that has an RA of plus or minus 4 hours from Polaris. It then goes on to say that Arcturus for instance would not be a good choice. Has anyone compiled a list of good stars by season in the east and west that would meet the requirements? I don't have the RA and DEC of various stars committed to memory so it would be helpful (to me at least) to have a good list of stars available so I wouldn't make the mistake of using a star like Arcturus which is similar in RA to Polaris. The other night I used Betelgeuse in the west and it seemed to be OK. Thanks, Brian Herbst
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Slewing sound frequency
Brian Herbst <dbherbst@...>
Hello,
I am a new owner of a 600EGTO mount and have had a couple of opportunities to use it. One thing that is obvious is that I am going to need an illuminated reticle for the callibration routine. Also, since my left eye is next to useless, I will be anxiously awaiting any polar alignment scope that may be made available (next to impossible for me to focus just one eye to infinity through the RA shaft thus seeing Polaris is very difficult for me). Anyway, I have a question for the veterans here: Is it normal for the mount to fluctuate in sound frequency as it is slewing to objects? I have the slewing speed set at 1200 so I would have expected a uniform motor 'whine' as the slewing is taking place. For the most part that is what I get but occasionally it will briefly go down in frequency (as though it is slowing down) and then recover to the steady whine that I presume represents the proper slewing speed. It seems to be OK regarding the pointing accuracy so maybe I am being picky with my observations?..... Any others here observing the same thing and is this normal? Brian Herbst
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Re: Abell Catalogue and things
Chris,
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All of the 2712 Abell galaxies are included so you can request any number from 1 to 2712. The Abell planetaries are a separate list and are not included in the keypad. We'll be changing the bindings on the manuals. Regarding polar alignment, Arcturus and Aldebaran both lie on a line that goes through the pole and Polaris. Use Capella, Rigel, Sirius, Pollux, etc instead. Marjorie Christen Astro-Physics
-----Original Message-----
From: Chris Spratt [mailto:cspratt@...] Sent: Monday, April 10, 2000 4:41 PM To: ap-gto@...; Subject: [ap-gto] Abell Catalogue and things I notice that the there are 2715 Abell galaxies listed in the GOTO Keypad listings for my 600E mount. (Not all the Abell objects are covered). Is there a "master" list of these somewhere as I don't want to have to scroll down the entire list and write it out to see what is there. Also, the keypad's (600E Goto) manual binding is a wee bit poor as the pages are already separating after only 2 weeks. I haven't used it that much either! (Especially not in the damp outside.) Anyone else noticed this? The poor binding that is. And - On choosing stars for polar alignment it is recommended in the 600E Goto Keypad manual that one doesn't use Arcturus as it is close to Polaris in RA. As Polaris is at 2 hours and Arcturus is closer to 14-15 why is this too close? Aldebaran on the other hand is close - under the recommended + or - 4 hours. Misprint perhaps? ------------------------------------------------------------------------ Special Offer-Earn 300 Points from MyPoints.com for trying @Backup Get automatic protection and access to your important computer files. Install today: http://click.egroups.com/1/2344/3/_/3615/_/955402877/ ------------------------------------------------------------------------
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Re: Safe zone of the 600E GTO mount.
Larry Denmark <kldenmark@...>
For those using TheSky, by Software Bisque to control your telescope, you
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can literally map out your own unique horizon lines and keep the scope within those set boundaries... very easy to do, too. Larry Denmark E-mail . . . kldenmark@... Web site . . http://home.att.net/~kldenmark/
----- Original Message -----
From: "Marj" <marj@...> To: <ap-gto@...> Sent: Thursday, April 27, 2000 12:10 PM Subject: RE: [ap-gto] Safe zone of the 600E GTO mount. Dear Mr. Bodart,simple circle around the zenith that the user can set on the hand controller.DigitalSky Voice in the future. Charles, are you listening?
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Re: Safe zone of the 600E GTO mount.
Dear Mr. Bodart,
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Welcome to the list. At the present time, the safe zone setting is a simple circle around the zenith that the user can set on the hand controller. Perhaps more complex safe zone controls can be incorporated into DigitalSky Voice in the future. Charles, are you listening? Marjorie Christen Astro-Physics
-----Original Message-----
From: Philippe BODART [mailto:phbodart@...] Sent: Monday, April 17, 2000 10:15 AM To: AP-GTO List; Subject: [ap-gto] Safe zone of the 600E GTO mount. Hi everybody I am a newbie on this list. I am retired and I live in Provence in the South of France. I built an observatory above my garage in the garden. I received my new telescope one month ago. It is a 155 EDFS refractor with a 600E GTO mount. For the moment I am fighting with the problem of the safe zone. I understand it is the angle between the optical axis and the vertical under which the OTA could hit the tripod (or the pier in my case). In other respects the overturn zone is comprised between the hour angles of 10:40 (OTA towards West) and 22:40 or - 1:20 (OTA towards East). As a result there is a very large safe zone for the hour angles close to -1:20.I give more details hereafter. Did you make the same observations? (I apologize if the subject has already been discussed in your list). Is there anybody at ASTROPHYSICS I could write to? Which e-mail? Thank you for advising me. Regards Philippe Bodart. 1.Overturn zone. The overturn zone is comprised between the hour angles of 10:40 (OTA towards West) and 22:40 or - 1:20 (OTA towards East). This zone is independant of the set up of the safe zone (see further on). It operates if you ask for a "go to".On the other hand with the keypad buttons you can reach any point geometrically accessible. It is tricky as it is possible to leave the hour movement working for a while without any trouble after having reached the aimed object. Unfortunately it increases the size of the safe zone when the OTA is close to the vertical towards East (see further on). It is a pity that this zone cannot be set up. 2.Safe zone. It is the angle between the optical axis and the vertical under which the OTA could hit the tripod (or the pier in my case). The most dangerous zone is obviously related to an hour angle of -1:20 (see above).I decided to recut the collar of my pier but you will see that it remains relatively annoying with a camera. With HA = -1:20 I rotated the OTA until it hit the pier and I noted the related value of the declination.The safe angle is the complement to 90 of the altitude (that can be calculated as a function of the hour angle, of the declination and of the latitude of the site with the ad'hoc trigo formula).The safe angle is not the same according to the way you are going towards the pier (N side or S side). My results are the following: -with an eyepiece 16(N side) and 18 (S side). -with the camera "horizontal" 23(N side) and 16(S side). -with the camera "vertical" 16 (N side) and 16 (S side). You see that with the maximum allowed set up of 20 it remains a risk with the camera "horizontal" (in fact parallel to the RA axis, that allows you to have the N upside on the photos). The set up of the safe zone prevents the OTA from tilting less than the requested value to the vertical , even if it is not dangerous. It is the case for hour angles bigger than 0:00 for example (the system ignores the azimuth). If you ask for a "go to" to a position comprised in the safe zone there is no movement and the keyboard displays the following message: "Outside safe zone.Slewing canceled". On the other hand with the keypad buttons you can reach any point geometrically accessible. Once again it is a pity you cannot set up the overturn zone as the choice made by the manufacturer spoils the safe zone. On the other hand it is a pity that the system ignores the azimuth when deciding if the movement is dangerous or not. It took me a long time to realize all that and it is also a pity that the handbook is not more explicit.
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Re: problem connecting ST-7 to AP1200 GTO
Charles Sinsofsky <strfire@...>
Hello,
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Contact A/P concerning this issue of using a ST-7 as an autoguider, and/or controller of the telescope...call then, I have used my st-4 with no extra equipment. please contact them at 815-282-1513 for details ok. charles sinsofsky
----- Original Message -----
From: John Kruis <J.A.Kruis@...> To: <ap-gto@...> Sent: Tuesday, April 25, 2000 10:26 AM Subject: [ap-gto] problem connecting ST-7 to AP1200 GTO Has anyone ever experienced problems connecting the SBIG ST-7 to the AP1200 GTO?
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Re: problem connecting ST-7 to AP1200 GTO
Dan Knauss <dknauss@...>
John:
You might need an SBIG relay box. I needed one several years ago with an ST-7 I was using with a VE Digitrack drive corrector. Without it, it drove the mount continuously in right ascension. Give SBIG a call. Dan Knauss Has anyone ever experienced problems connecting the SBIG ST-7 to the AP1200 GTO?
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Re: problem connecting ST-7 to AP1200 GTO
Ray Gralak <ray@...>
Hi John,
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I use an ST-8E which is basically the same camera (but with a different CCD chip) with my 1200 GTO with no problems. The TIC cable by the way is a simple straight through 6-wire cable you can get from Radio Shack or any other electronic store. I would try getting another cable to see if that is the problem. When you do start to guide with the 1200 make sure you set the button move speed down to 0.25x or 0.5x, otherwise the mount will move too fast when guiding. -Ray Gralak
-----Original Message-----
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problem connecting ST-7 to AP1200 GTO
John Kruis <J.A.Kruis@...>
Has anyone ever experienced problems connecting the SBIG ST-7 to the AP 1200
GTO? When I connect the St-7 TIC-cable to the mount it starts to move westward. I checked cable connections/pinouts but I cannot get it right. My ST-7 is about 4-5 years old. John Kruis
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