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Introduction to AutoMapping
This document assumes familiarity with Orchestrate scripts and TheSky's Image Link. For details on Orchestrate please read the Orchestrate Scripting Documentation. If you are unfamiliar with Image Link, please see TheSky User's Manual and the Image Link URL for details. For an extensive definition of issues related to telescope pointing please refer to the following paper by Patrick Wallace, author of TPoint.
The term Auto-Map is used to describe the process of modeling a telescope without human intervention. Imagine your telescope training itself how to point better! Here is how Auto-Mapping is performed.
Summary
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TheSky slews the telescope to a pre-defined set of azimuth and altitude coordinates
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When the telescope arrives at each position, a short exposure CCD image is acquired using CCDSoft.
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TheSky uses this image to determine an astrometric solution.
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Once TheSky has determined exactly where the telescope is actually pointing, these coordinates are added to the TPoint model.
This method of telescope modeling is extremely efficient since only one image per azimuth and altitude coordinate is needed. The astrometric solution is almost instantaneous; about one hundred accurately mapped points can be acquired in just over an hour on a typical system, less time if you have a sensitive CCD camera with a fast download.
Preliminary Information
The Windows Scripting Host must be installed to execute the these VB compatible scripts. When you can run scripts you are ready to use the Auto-Mapping script. To use the Auto-Mapping script, you will need to know the scale of your optical system in arcseconds/pixel. If you do not know what your scale is you can use Image Link to compute it for you. Image Link is used in conjunction TPoint to give you Auto-Mapping capability.
Here is how.
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Establish a link with the telescope in TheSky (Telescope | Link | Establish).
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Click Edit | Insert to insert a TPoint model.
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Export azimuth/altitude coordinates from TheSky) <--- Click here for how this is done!
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Take a CCD image (about 5 - 10 second exposure) in CCDSoft (Camera | Take Exposure).
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Image Link the image to accurately set the scale in TheSky.
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Sync the telescope on the Image Linked coordinates.
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Run the Auto-Map script supplied below.
The Auto-Mapping Procedure
Using TheSky Professional, Orchestrate, CCDSoft and your CCD Camera, you can use a Visual Basic script to automatically collect TPoint mapping data.
To begin, from TheSky, click Telescope | Server Settings and mark the Allow Remote Connections option. From CCDSoft, click Camera | Server Settings and do the same.
Server Settings for TheSky6
Enabling Remote Connections
Allow for Remote Mapping with
Orchestrate
Server Settings for CCDSoft
CCDSoft's Server Settings
Allow for remote mapping with
Orchestrate
The Auto-Map script will fail if you do not mark the Remote Clients Use Orchestrates AutoMap Capabilities in both CCDSoft and TheSky.
TheSky versions 5.00.102 and later, and CCDSoft versions 5.00.073 and later do not require Orchestrate for scripted operation. The above Server Settings must still be checked, however.
Step 1 - Setup the Hardware and Software
First get the telescope initialized and pointing on its' own. The best way to accomplish this is to use our Image Link and Sync option. Please refer to the following page Image Link and Sync for complete details.
TheSky can create a list of target Altitude and Azimuth mapping points for TPoint. These points are altitude and azimuth positions, not right ascension and declination or stellar positions. The Earth based coordinate system is used.
Creating the Alt/Az Mapping File <--- Click here for EXACTLY how
The text file name you choose is what will be used by the auto-mapping script. The script loads the points one line at a time from this file, takes an image, links the image, and maps the point. In the script file here is the line that will need to be changed to use the mapping data file you have created above,
szPathToMapFile = "c:\Program Files\Software Bisque\Orchestrate\MAPPING.TXT"
Just change the drive letter, path, and filename accordingly. If you run a script without a file that contains altitude/azimuth points the telescope will not slew where you expect.
The Auto-Map Script
Make sure that you've downloaded the latest version of Orchestrate to obtain the latest AutoMap.vbs script file.
For the most part the auto-mapping script takes care of everything. Don't hesitate to change the script. The following lines in the script are what you will need to change before attempting your first automated mapping run. You must tell the auto-mapping script where the data file of altitude azimuth points is located. Please see above for details on creating the mapping data file.
szPathToMapFile = "c:\Program Files\Software Bisque\Orchestrate\MAPPING.TXT"
Choose the shortest exposure you can where you still have enough stars on the image to perform an Image Link. Consider 2 x 2 or even 3 x 3 binning when using 9 micron detectors. A good rule of thumb is to try to achieve 2.5 to 3 arcseconds per pixel scale on the CCD image. Binning maximizes efficiency in that a fainter magnitude will be reached quicker, and the amount of data downloaded will be faster; hence, the entire auto-mapping process is optimized. Do not be concerned about loosing resolution when binning, the lower resolution will have no effect on the final TPoint model.
More details and complete descriptions of the commands used in scripting can be found in the RASCOM help file distributed with the latest version of Orchestrate. The script line below sets the camera's exposure time:
objCam.dExposureTime = 8.0 < ---- Use 8 second exposure
If you wish to set the binning from within the script here is how. The default is whatever binning option you have set in CCDSoft prior to running the script.
object.Resolution [ = Resolution ]
Please see the RASCOM help file for complete documentation on this and all methods and properties used by the auto-mapping script. Other Sample scripts can be found here.
YOU MUST HAVE THE WINDOWS SCRIPTING HOST installed first < Click here..
Error Handling
There is a flag in the auto-mapping script responsible for how the script behaves when an error has been encountered. Errors include Links that fail, slewing to altitude azimuth points that the scope cannot reach, no mapping data file found, and so on.
IMPORTANT! Run the script using error checking enabled (set to on) the first time. When you have everything working with a small set of points then edit the script and turn off the error checking. The default error setting stops the script when an error has occurs. This is a problem if you want to map while you not at the scope. To override the halting on errors, simply change the flag to a value of True as shown below.
bIgnoreErrors = True
Remember, this should not be done until you are sure that everything else is working first. When you have used the scripting for awhile you can comfortably set the error checking off and the script will simply run until completion. If there are images that do not link they will simply be ignored; they will not be added to the TPoint model.
Step 3: Run the Script
Double-click automap.vbs using the Windows Explorer to begin execution. YOU MUST HAVE THE WINDOWS SCRIPTING HOST installed first < Click here..
Polar Alignment Help
TPoint is an extremely powerful piece of software that can very accurately asses your pointing system and more importantly correct for any and all repeatable pointing errors. It is always best to minimize all aspects of the system at the hardware level first but you need not be concerned with non-orthoganality of the optical tube assembly or even miss-polar alignment in regard to pointing because TPoint completely takes care of it.
More often than not the only hardware change to the system will need to be in the polar alignment itself. With a good polar alignment and a reasonably perpendicular mounting of the OTA one can expect 3 to 5 arcminutes RMS pointing with the Paramount GT-1100 with NO TPoint model present! For an extensive definition of problems related to telescope pointing please refer to the following paper by the master Patrick Wallace, author of TPoint. In order to use TPoint effectively you must understand how to use it. Unfortunately, this can be very difficult for first time users of this advanced modeling software.
If you are experiencing difficulties in evaluating your polar alignment when using TPoint you can email us your TPoint documents.
First please refer to the following page for in depth details,
How to Polar Align using TPoint as a tool <-- For details click here.
Shoot for a good model of 15 to 20 stars and we will be happy to evaluate the data and tell you how much to adjust your mount. Note that the Paramount GT-1100 is far easy than most mounts in this regard because of the calibrated fine threaded Altitude and Azimuth Adjustment screws yielding 5 arcminutes/turn of the slew.
For those with the LX200 series mounts or others that are not calibrated I recommend using a Live video CCD camera that has been calibrated to your scope. This will give you visual feed back on the monitor indicating how much you are adjusting your mount. This works extremely well and will take all the guess work out of it. Software Bisque sells .01 lux low light level real time CCD cameras for $100.00. These cameras also work great on planets and for initial live video mapping when working on your polar alignment.
In one simple word TPoint "WORKS". Currently there is NO better telescope modeling software on the planet. Period. Beware of other "Knock-off" products that are limited to only 6 basic equatorial terms. These will ALWAYS yield inferior RMS pointing!
There is a reason why the major observatories like the Keck choose to use it. If you are not familiar with TPoint and/or do not completely understand the information it provides it is difficult to use it to Polar Align the mount. When familiar with it you can easily get an accurate polar alignment in less than 2-3 hours time. This level of accuracy usually takes several days. That is, a polar alignment at the arc minute level in both Altitude and Azimuth. I routinely use TPoint with portable and permanent installations and always achieve near perfect polar alignment with minimal effort.. TPoint is extremely accurate in assessing the polar misalignment when used correctly. After two or three iterations you can get a very precise polar alignment using the modeling data. This is not a simple thing for first time users. Please email your modeling data here and we will look at it and get back to you with the polar alignment information and a new fitted model.
LX200 Users
There are two different models of the LX200 series telescopes from Meade Instruments Corporation. The older non-HPP models and the newer HPP models. HPP is an acronym for High Precision Pointing. If the scope is not an HPP model you will be limited in how well the scope will point when using it with TheSky. The non-HPP models can only accept object coordinates from the serial port at the arc minute level! This is a limitation imposed by the telescope. TheSky is accurate to the arcsecond level when computing object positions for a given date and time. This is far more accurate than the telescope is actually capable of pointing. This does not exclude data entry errors as found in many popular stellar and non-stellar catalogs like the NGC-2000. For a complete synopsis of catalog related issues please refer to the following Sky & Telescope article reprint named Catalog Capriciousness by Stuart Goldman. For an extensive definition of problem related to telescope pointing please see the paper by the master Patrick Wallace, author of TPoint.
If the telescope is not an HPP model you will not be able to use TheSky's Motion Controls at anything less than the 1 arc minute or higher increments. Also, the telescope will not be able to accurately position objects when slewed to from TheSky. This is why objects may seem to be off when using TheSky to drive the telescope to an object when compared to using the LX200 hand paddle. This limitation is again imposed by the telescope itself and has nothing to do with TheSky's computations.
To test your LX200 telescope for the long format mode here is what you can do. Email me the text the telescope returns when you issue the ":GR#" (Get RA command) before issuing the long format mode and the text returned after issuing the long format command. This will answer all questions regarding the subject. From TheSky's terminal mode issue the following simple commands in the order they appear below.
:GR# [ENTER]
(EMAIL ME THE STRING RETURNED FROM THE SCOPE)
:U#[ENTER]
:GR#[ENTER]
(EMAIL ME THE STRING RETURNED FROM THE SCOPE)
It is that simple. If the telescope employs the long format mode you will want to use it at all times with TheSky.
IMPORTANT! Do not use the High Precision Pointing feature as described in the LX200 manual. If you enable the High Precision Pointing the telescope will always wait 8 seconds before slewing and always slew you to the nearest brightest star first, not to the object you wish to point to. This is the method of two-step pointing whereby centering the nearby star first manually and then off set slewing a small distance ensures a high degree of accuracy. When using TheSky/TPoint and the LX200 you do not need to do this. TPoint takes care of it.
Motion Control Dialog
Arcsecond motion not
available on non-HPP models
If the telescope is an HPP model you should always use the long format mode when using TheSky. The Long Format mode allows the coordinates from TheSky to be sent and received at the arcsecond level. You should always use the long format mode when using TPoint with the LX200 series scopes. The long format mode is not "on" by default nor is the status saved when the telescope is turned off. Therefore, the long format command must always be re-issued when the telescope is initialized. Failure to employ the long format mode will limit the telescope's performance when used in conjunction with TheSky.
See TheSky's Help file for details about using the Long Format Mode.
After the scope has been sent the long format command there is no verification from the scope that it worked. If you send the command a second time you will turn off the long format mode. It is a simple on and off toggle. If you wish to see the effect of the long format command first query the telescope for the current Right Ascension BEFORE issuing the ":U#". This is done with a ":GR#" from the terminal mode. Again refer to the LX200 manual for details. The telescope will respond with a Right Ascension in a certain format. Next issue the long format command ":U#" SEND and then follow it with the ":GR#". By comparing the two sets of coordinates you will see exactly what the difference is between the normal mode and the long format mode. Remember these commands are CASE SENSITIVE.
In lieu of using TPoint to automatically correct for pointing errors you can also use a script to accomplish the same thing as High Precision Pointing, automatically. This is done with our Image Link technology. We have relied on the following method for many years when using the LX200 series telescopes. Although not as efficient as employing TPoint the ImageLinkAndSync visual basic script works extremely well and simply takes a little longer for each image to be centered.
The ImageLinkAndSync script supplied with Orchestrate will accomplish the following tasks. When the telescope is slewed to a new position a quick short exposure (~10 to 15 seconds) is taken first so that TheSky can astrometrically figure out where the telescope is "truly" pointed. Note, if the telescope were actually capable of all sky pointing at the 30 arcsecond level you would not need to take this extra step. However, without using modeling software like TPoint an out-of-the-box LX200 will NEVER point better than several arcminutes (5 to 10 arcminutes of true RMS all sky pointing is common). After the short exposure CCD image is analyzed with Image Link the telescope is Synced on these arcsecond coordinates (HPP models in the long format mode only). Even if the telescope is only pointing to 30 arcminutes, one half a degree, Image Link will solve the problem.
Please see "ImageLinkandSync.Vbs" Visual Basic script that is provided with Orchestrate.
ST-6 Users
Make sure that the ST-6 images are resampled so that the pixels are square before using Auto-Map.
You can manually map your telescope with the
ST-6 CCD by doing the following. First create an evenly distributed
set of points in
TheSky so you have a map of where to go. Once the
points are displayed in
TheSky slew to Map Point #1 (Start), take a short exposure (~15 seconds),
Image Link the exposure and set your scale in ,
Sync the telescope on the Image Link Coordinates, then slew to
the next
position (Map point #2),
Image Link, and then Map
.
You must click Sync (found under the Telescope Tab on the expanded Object
Information dialog box) once. This is followed by the
mapping button
for the rest of
the points. This is still very efficient in that you only take one image
per slew to map the point. You will always get the best mapping when you
map with the CCD camera fixed in place (preferably with a North Up orientation)
and then map on the Image
Link arcsecond accurate coordinates.
Object Information
Dialog Box
Smaller version click
highlighted down arrow
To make the Object ID box less obtrusive you can shrink or expand it using the Down arrow located in the lower right corner of the Object ID dialog box. In this mode you cannot accidentally press the Sync button. You can only slew and map from here avoiding the inadvertent use of the re-sync which will ruing a model!
Issues Related to Poorly Pointing Telescopes
If your telescope does not point accurately on its' own you can alter the Image
Link Setup to make the searching area larger. This is the case with scopes
that cannot point well on their own without TPoint and or a Paramount that has
not been aligned with the pole to a high degree of accuracy. I recommend
getting for a good polar alignment with the Paramount; not from a tracking
standpoint rather from a telescope pointing issue. This makes modeling a
lot easier. In fact, the Paramount will point as well as 5 arcminutes with
no TPoint model present when you have a good polar alignment and the scope is
mounted close to orthogonal.
Increase the Search
Radius
Search Radius Defined in
"Fields of View" 3 times your field above!
By increasing the search radius (in fields of view) you are more likely to get Image Link to find a match. Try changing the default size of 2 to 3 or 4 TIMES your actual field of view. The larger the searching area the slower the routine but this is not significant when you have set your scale. This should help Auto-Map when the target is not on the CCD detector.
Minimum System Requirements (Software and Hardware)
Software |
The latest version of
Software Bisque's Professional Astronomy Software Suite, including:
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Hardware |
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