SOFTWARE MANUAL Autopointing and LPT with Sequence04

Transcription

1 SOFTWARE MANUAL Autopointing and LPT with Sequence04 New: Sequence07 features in the appendix E ASA Autopointing and LPT with Sequence04. 10/2011 1

2 CONTENTS 1. Introduction - a faster way to success with Sequence 2. Software Requirements 3. Starting Sequence 4. Plate solve settings 5. Current Location and Hardware 6. Background Design 7. Creating a Pointing File 8. Horizon Limits 9. Defining your Autopointing Grid 10. Astrometric Analysis 11. Introduction to Local Precision Tracking (LPT) 12. Using LPT 13. Synchronizing your Mount with Sequence 14. Apendix/Support 15. Sequence 7: New features CAUTION: Please read the software manual carefully before operating the mount! Information in this document is subject to change without notice and does not represent a commitment on the part of Astrosysteme Austria. It is against the law to copy the software on any medium except as specifically allowed in the license or nondisclosure agreement. The purchaser may make one copy of the software for backup purposes. No part of this manual may be reproduced or transmitted in any form or by any means, electronic or mechanical, including (but not limited to) photocopying, recording, or information storage and retrieval systems, for any purpose other than the purchaser s personal use, without the express written permission of Astrosysteme Austria. The software products described in this document are furnished under a license agreement or nondisclosure agreement. They may be used or copied only in accordance with the terms of the agreement. Astrosysteme Austria GmbH, ASA Astrosysteme GmbH, Galgenau 19, A-4212 Neumarkt i. M. ASA Autopointing and LPT with Sequence04. 10/2011 2

3 1 Introduction - a faster way to success with Sequence Sequence ist a software programm which can be used as an automation tool in conjunction with Autoslew. At this time, Sequence offers a set of tools for automatically creating pointing files or to improve overall tracking performance through a local precision tracking routine. New features will be added in the future. Please note: Sequence should only be used, if the main processees and funtions of Autoslew are working and well understood. These processees inlcude manual creating pointing files, polar alignment, an understanding of CCD Cameras in conjunction with MaximDL and a base knowledge of Pinpoint - the astrometrical engine of Bob Denny. Sequence is not a software solution in compensation for a lack of knowledge of Autoslew. 2 Software Requirements Autoslew and Sequence ( MaximDL with camera and camera connection to MaximDL ( Pinpoint (Astrometric Software) ( GSC Catalog (or other) Ascom Plattform ( Planetarium Software recommended (Ascom compatible) 3 Starting Sequence Start Autoslew then Maxim DL and connect your camera with MaximDL. Careful! Do not connect Autolsew with Maxim DL. Execute Sequence by double clicking on the Sequence Icon on your computers desktop. Once Sequence has started you will see a blue screen with six light blue buttons to the left, of which only the first three will be active on start-up. ASA Autopointing and LPT with Sequence04. 10/2011 3

4 To activate the communication between Autoslew, Maxim DL and Pinpoint, click on the connect button (located on the left side of the screen). Sequence will then attempt to establish a communication connection between all programs. Sequence will automatically detect the paths to all programs. If Sequence connects successfully, all six buttons will be activated. 4 Plate solve settings Once your software is interconnected, in Sequence, click on the settings tab and then choose Plate solve settings. When the submenu opens, you can go ahead and custom set your parameters for the plate scale, color band and choose the path to your Astrometric catalogue on your hard disk (consult your pinpoint manual to find where on your hard drive your catalogue is located)! TIP: Field size (or Arcseconds) per Pixel = Pixel size (in Micrometers) divided by Focal length times 206,3. If you are using binning mode, you will have to multiply your results with you binning mode. Example: A camera has a pixel size of 5 micrometers and is being used with a telescope with 1000mm focal length x 206,3 = 1,0315 Hence, one pixel is then = 1,0351 Arcseconds. ASA Autopointing and LPT with Sequence04. 10/2011 4

5 You can leave Object detection and Solve parameters can stay unchanged under certain circumstances. If you are using a very large star catalogue together with short exposure times it is recommended to adjust parameters for "Maximum Magnitude" in the frame "Reference Catalog". To achieve faster solve rates, good results can be achieved by setting the parameters for "Maximum Magnitude" to the marginal size on your exposure. This is especially recommended for the very large and deep USNO catalogue. To find out more about tuning these parameters, again consult your Pinpoint manual. To save your parameters, go to File and then Save in your menu bar. To save your parameters under a custom file name, go to File and then Save in your menu bar. To load you custom parameters, go to File and then Open in your menu bar. To exit Sequence, go to File and then Exit in the Menu bar. ASA Autopointing and LPT with Sequence04. 10/2011 5

6 5 Current Location and Hardware In the Menu bar, click on Settings then click Current Location and Hardware to open the Current Location and Hardware menu. Here you can enter the coordinates of your observing location. When you activate the option use Autoslew coordinates then the coordinates of your location and time are taken from Autoslew (see Software Manual Autoslew). You can also tell Sequence, what type of hardware you are using. For DDM60 and 85 mounts use the option Equatorial German. Mount type For the DDM85 and DDM60 you should set this parameter to Equatorial German, for the DDM160 set the parameter to "Equatorial Fork". Dome If you are using an automated dome, you can tell Sequence to rotate the dome respectively to the telescope Azimut. Here you can choose one of two options: 1. Control Dome Directly If this option is activated, Sequence will control the dome directly (will position the correct azimuth and will wait until the dome is positioned correctly before starting the exposure. To choose your dome (Ascom driver necessary) click on [Select Dome] and then select the correct driver for your dome using the Ascom Chooser. 2. Autoslew Controls Dome If this option is selected, Sequence will assume that Autoslew will control the dome. In this case, your dome will have to be selected and connected in Autoslew. To save your parameters, go to File and then Save in your menu bar. To save your parameters under a custom file name, go to File and then Save in your menu bar. To load you custom parameters, go to File and then Open in your menu bar. To exit Sequence, go to File and then Exit in the Menu bar. ASA Autopointing and LPT with Sequence04. 10/2011 6

7 6 Background Design You can easily change the background color of Sequence by choosing "Settings" in the menu bar and then choosing "BackGround Design". A drop down menu will appear in which you can choose either blue or red. ASA Autopointing and LPT with Sequence04. 10/2011 7

8 7 Creating a Pointing File To start creating a pointing file, click on the button Autopoint. The Autopoint menu options will open. First, you can set the location of the folder where the image files will be stored by clicking on SET. Choose a folder on your hard drive and click OK. The image files will be stored in your chosen location together with a date and time stamp. The Autopoint Menu will also allow you to adjust the following parameters: Exp. Time Filter Nr. Settle Time Azimut Factor Binning Limit Distance Make Dark First Confirm each exposure Exposure time (of each image) Filter number or filter wheel number Idle time between image exposure This parameter needs to be set to a delay value to allow the mount to swing down after slewing and before commencing with high accuracy tracking. This usually takes 2-4 seconds. You can test your setup in using an Autopointing file where you only have the simulator camera activated in MaximDL and observe the REC and DEC display in Autoslew. If the CCD exposure in Sequence starts before the numbers in the display stop changing (the begin of a CCD Exposure will be indicated through the blinking CCD camera symbol) then you should set the value for "Settle Time" higher. Binning combines a set of pixels together, giving you different pixel sizes with the same camera. Binned pixels allow for a shorter exposure time, faster download times but provide lower resolution. (i.ex. Bin 1x1= 1 Pixel, Bin 2 x 2 = 4 Pixel, Bin 3 x 3 = 9 Pixel) 2 or 3 x Binning is recommended, since it will hardly decrease the accuracy of Autopointing but will greatily reduce exposure and solve time. Here you can choose if you would like to make a dark frame before commencing with Autopointing or not. Since MaximDL will make a dark frame automatically it is advised that you turn of this feature in Sequence, since during remote operations covering the optics will not work in most cases. This parameter will aid you if you have a dome which cannot be controlled by Autoslew. Autoslew will wait for each exposure until you manually have repositioned the dome. Please Note: The above values correspond to values in Maxim Dl. The values of the parameters set here will override corresponding parameter settings in MaximDL. ASA Autopointing and LPT with Sequence04. 10/2011 8

9 8 Horizon Limits To prevent Sequence from moving under the horizon or into obstacles above the horizon when imaging (pointing your camera into obstacles such as trees, building or hills) you can set horizon limits and achieve a good open sky coverage for your pointing model. Setting these limits basically tells Sequence which area of the horizon (in degrees) to avoid during imaging. It should be noted, that there will be no consequence for accuracy when creating an autopointing file in images into an obstacle like a tree, clouds or mountain, since these images will be excluded during solve process automatically. However, you can save time during solve if you tell Sequence to exclude these obstacles before hand. To set the horizon markers for your location, click on the button "Create Horizon" and enter the lowest horizon height (in degrees) which are attainable for you and for which you would later like to make exposures for your pointing file. Please Note: The values for the parameter horizon limit in Sequence must be the same value or a higher value as set in Autoslew! Additional horizon limits which go beyond this minimal horizon limit can be set individually in the right field with help of your mouse. In the following example the horizon is limited further by obstacles drawn in the South and North West. ASA Autopointing and LPT with Sequence04. 10/2011 9

10 Once you have drawn your limits click on the button Finished located to the lower left side of the hemisphere diagram. Parameter set in the Horizon configuration can be saved in the Menu bar with menu items "File" and "save". The doted lines in the hemisphere diagram indicate where the Meridian Flip will occur and your flip options will take effect. You can set your flip options in Autoslew (go to the menu bar: Mount-Type > Limits- How far can you go through the Meridian with your German Mount?). If you then click on Autopoint the information will then be displayed correctly. This limit value will set how far your mount will slew past the horizon. This value is important specifically with German mounts, where the telescope can bump into your tripod or pier (does not apply to modified equatorial pier). ASA Autopointing and LPT with Sequence04. 10/

11 9 Defining your Autopointing Grid The Autopointing Grid parameters define the areas in the sky where Sequence will automatically take images that will be processed and then used for your auto pointing file in Autolsew. There are two different ways to tell Sequence where to take images and to define the Autopointing Grid: 9a) AutoGrid Start by clicking on the button AutoGrid. In Auto Grid (automatic grid) you can define grid distances in DEC and RA, as well as define a maximum and minimum height. You can also define beginning and ending hours in degrees as well as beginning and ending declinations. Grid Dec, Grid Ra This will set the resolution of your autopointing file and hence also the amount of stars. Distance set to small can result in a extremely large amount of images taken, less than 10 degrees should only be defined for special applications (like stationary observatories aso.) and will usually not render a better performance. A large amount of stars in your pointing model will only produce benefits highly reproducible OTAs (small or no mirror shifting). Min Alt Max. Alt The minimal height above horizon is an additional option to determine for the current specified file from which minimal height measurements can begin. It makes sense to create pointing files only where your main areas of photography will lie. If you will only take images above horizon heights of more than 40 degrees, it makes little sense to make an autopointing file above 15 degrees. In this specific case starting at i.e. 30 degrees would be better. It should also be mentioned, that it will not harm to set minimum altitudes that lie beyond your horizon limits (see chapter 7 Horizon Limits). Those positions will be ignored. H start, H end The hour angle will determine the angle of the REC Axis depending on clock time. In the Autoslew display -180/+180 is the Northern direction and 0 South, whereas towards East numbers will be counted negative while towards West the numbers will be counted positive. If for example you set the parameter H start = -180 and H end = 0, then the Autogrid will only create positions in the Eastern part of the sky. Start Dec, End Dec Under certain circumstances it can make sense to also enter limits here (For example a fork mount that only makes possible a minimal declination since otherwise the OTA would hit the fork towards South. It especially makes sense to enter an End Dec value, since near the celestial pole observations are hardly made and the mount usually displays higher inaccuracies in this area. End Dec should therefore not contain a value higher than 80 degrees. German Mount Flip Options Here you should make the decision, which meridian flip option you would like to choose. You can either set a check mark on "All East", "All West" of choose both options. Reverse on end of Curve will cause the mount to return the same path backwards after reaching the maximum hour angle h. In this case the positions will be exposed twice, once from East to West and once from West to East. This will make mirror shifting problems and other non-reproducible errors visible in Autoslew (after a configuration has been calculated) and Autoslew will calculate an average from both directions. Add random Grid within ranges This function is used for simulation purposes only, or when producing a random grid. ASA Autopointing and LPT with Sequence04. 10/

12 Then, continue by clicking on the button New Grid. To start your imaging run click Start. The System will then take an exposure on every point of the grid. The files are then saved to a folder (see Chapter 7 Pointing File configuration), together with a date and time stamp. The images are stored in the Sequence program folder. By clicking the button Saves current Grid you can save you current grid. You can then re-load and use your grid t at a later stage by clicking the button Opens a Grid. With the simulation button (arrow button) you can simulate your auto pointing. ASA Autopointing and LPT with Sequence04. 10/

13 9b) MouseGrid Click on the button "Create Horizon" und enter lowest horizon height (in degrees) which is attainable for you and where you would later like to create exposures for your pointing file. Please Note: The values for the parameter horizon limit in Sequence must be the same value or a higher value as set in Autoslew! Start by clicking on the button MouseGrid. With Mouse Grid you can manually enter points by clicking into the sky window, whereas a left mouse click will set points in the eastern part of the sky and a right mouse click will set points in the western part of the sky. Click on the left mouse button to mark positions that you later would like to approach on the East side of your mount respectively the right mouse button for the West side. This distinction is necessary, since you have positions near the meridian which the mount can approach from both sides. East and West sides are color coded differently. The markers are set in the same order as chosen. ASA Autopointing and LPT with Sequence04. 10/

14 Once you have set all markers, continue by clicking the button Finished. To start your imaging run click Start. The System will then take an exposure on every point of the grid. The files are then saved to a folder (see Chapter 7 Pointing File configuration), together with a date and time stamp. The images are stored in the Sequence program folder. By clicking the button Saves current Grid will save your current grid. You can then re-load and use your grid at a later stage by clicking the button: Opens a Grid. With the simulation button (arrow button) you can simulate your auto pointing. Requirements for Autopointing When an autopointing file is created, Sequence will save the telescope coordinates used by Autoslew in the Fits Header of your CCD images. Consequently, images will be astrometrically calibrated (solved) by Pinpoint, whereas Pinpoint will use the telescope coordinates saved by Autolsew in the fits header as a starting point for the search. Pinpoint cannot solve images if one lies notably more than 1/2 of an image diameter amiss. Autopointing is hence not suitable for correcting rough errors in your mounts set up or even correcting collimation errors. In any case, before the first image is taken the mount should be synced to a known star first. When working with long focal lengths and/or small field of views it is also makes sense, to create a manual pointing files with a view stars on each side of the mount first and to then create a more enhanced pointing files using this set up. IMPOR- TANT! Should you use a configuration to create your Autopointing file (which makes sense in small field of views) you should also have it pre loaded in Autoslew before loading the new POX file. Only then can Autoslew take into consideration that coordinates have already been partially corrected. Combing two or more Autopointing files You can easily combine more grids, considering that in between the files the mount was not synched again. A typical example would be a full moon night where at the position of the moon images could not be solved correctly. When the autogrid is complete, you can create a manual grid where before the position of the moon has caused disturbances (in the meantime the moon has traveled further) and then have Sequence save the images in the same folder. Since Sequence will always solve images folder wise it is only important, to make sure all images to be used are contained in the same folder. ASA Autopointing and LPT with Sequence04. 10/

15 10 Astrometric Analysis As soon as Sequence has ended the imaging run, you can continue with the astrometric analysis of the images. The astrometric analysis is needed to create a pointing file. To start the analysis, click on the button Solve folder and create Pox file button You will then be prompted to locate the image folder: Navigate to the folder where the image files have been saved and click Ok. Save the auto pointing file (.pox file) with a filename of your choice. After Sequence has finished analyzing the images it will report solving finished in the light blue bar, indicating that the Pox file (auto pointing file) has been created and saved. Should no image be solved at all, it is very likely that your values for "Horiz. Und Vert. Scale" of your CCD camera is not set correctly in Pinpoint. Should many images not be solved but which you consider to be qualitatively adequate try to modify your Pinpoint settings in order to achieve better results. It is normal, that certain images will not succeed and will only decrease the results in a minor way. In moon nights, for example, images near the moon are seldom any good. After the Pox file has been created switch to your mounts controller software Autoslew. In Autoslew open the previously saved Pox file and let Autoslew calculate the configuration as usual (for more information consult the Autoslew software manual). You can now start with unguided imaging or start observing the night sky visually. ASA Autopointing and LPT with Sequence04. 10/

16 11 Introduction to Local Precision Tracking (LPT) LPT is one of the most exciting features of Sequence. Sequence can analyze a partial area of the sky surrounding the object which would be imaged later on. This is an alternate way of creating a time consuming pointing file. In effect, this means that imagers can set up there mount, analyze, point and shoot very quickly. As an example: Let s say you want to image M32. Sequence will analyze the specific part of the sky surrounding the object you need to image. It will then create astrometric calculations and analyses based on that object. This is of considerable value to astrophotographers working in the field, since pre-imaging preparation will go much quicker and more efficiently. Also, this feature is the recommended method for users of Schmidt Cassegrain telescopes where mirror stability can be a problem when creating a pointing file over a large portions of the sky. The method described in the following chapter should be used for tracking in the field, when small or no pointing models are available. As already mentioned, this method is highly recommended for systems that use OTAs where mirror shifting can be an issue (such as SCT s). 12 Using Local Precision Tracking The Local Precision Tracking option in Sequence will limit the automatic creation of a pointing model (an astrometric calculation) to a sequential area of the sky of under 15 degree Ra angle. If you set up in the field and with your mount roughly polar aligned, you can use this feature without having to make a time consuming pointing file. Please note: Field Rotation (if bad polar alignment was performed) will not be corrected! In your planetarium software slew your mount to the object you would like to image, switch to Sequence and click on the button Local Tracking (light blue buttons to the left of your screen). Sequence will take an exposure, create a plate and solve the image. Sequence will then move 15 degrees along RA to take another plate solve. Lastly, returning to the initial starting point to take another image, exposing and solving the image again. You can now start to image in an area of about 15 degrees. For longer exposure, the above steps can be repeated (it only takes LPT around 1-2 minutes to take images & to analyze the images for a new run). Please note: The LPT module needs the comet tracking feature of Autoslew to be activated. The activation is done automatically! ASA Autopointing and LPT with Sequence04. 10/

17 13 Synchronizing your Mount with Sequence You can Auto synchronize Sequence with any ASCOM compatible Planetarium Software by way of an astrometric method. The auto sync method will compare the reported position by your planetarium software with an astrometrically analysed image taken by your camera (representing the actual position of where your mount is pointing to). Sequence will take the actual pointing position of your mount and report it back to your planetarium software, correcting the initial view to the actual one. To perform auto sync, simply click on the Synch button in Sequence! Please note: The region of the sky you would like to synchronize (IS-Position) with the projected area in your planetarium software (Should-Position) may only deviate less than half a frame. Tip: Since you have to center a star manually during polar alignment, it makes sense to synchronize then! ASA Autopointing and LPT with Sequence04. 10/

18 14 Appendix / Support The following list of steps presents an outline of the order of tasks you need to perform for Sequence to perform successfully. If you have followed those steps in Autoslew already, you may continue with step Nr. 10. If you have not performed these tasks, start with step Nr. 1 and consult the Autoslew manual for a more detailed description of the individual steps. 1. Synchronize Autoslew with your planetarium software 2. Create a pointing file or auto pointing file with a minimum of 5 stars (for the DDM60 the requirement is at least 7 stars) 3. In Autoslew, load your pointing file or auto pointing file and let Autoslew calculate it. For the DDM60, you need to check the option also optimize encoder or motor resolution when you let Autoslew calculate your file for the first time only! 4. When Autoslew finished calculating the pointing file, click the button Use now and OK 5. Align polar axis with Polar Adjust (Tip: Since you have to center a star manually during polar alignment, it makes sense to synchronize then!) 6. Clear old Configuration (For the DDM60 choose No when prompted with the question Delete Encoder Resolution ) 7. Create a pointing file or auto pointing file with a minimum of 5 stars 8. In Autoslew, load your pointing file or auto pointing file and let Autoslew calculate it. For the DDM60, you need to leave also optimize encoder or motor resolution BLANK this time (unchecked)! 9. When Autoslew finishes calculating the pointing file, click the button Use now and OK ( Use now and save or Use now, save and use on next start if the mount is in a permanent setup, like on a pier) 10. Continue with the Chapter Using Local Precision Tracking in chapter 11 of this manual Tip: Should you find at step 3 after calculating your pointing, that the deviation during polar alignment is very low (benchmark < 0,5 degrees), you can skip step 5 to 9. Tip: If after step 3 you find that the deviation during polar alignment is very low (benchmark < 0,5 degrees) you can skip step 5 to 9. Please note: Field Rotation (if bad polar alignment was performed) will not be corrected! The longer the focal length and exposure time, the better polar alignment should be! If you would like to send us your feedback or you have questions or experience problems, please contact us at support@astrosysteme.at ASA Autopointing and LPT with Sequence04. 10/

19 15 Sequence 7: New features Hysteresis Time flex Multi Position LPT Slew Settle Time The most important changes in this version are a multi position LPT with a direct interface to Autoslew and also a method to check the performance of your telescope (not mount!). Slew Settle Time There is a new function added called Slew Settle Time. It will measure the time that is needed for the telescope to continue precise tracking after a slew. It is important for the accuracy of the following measurements that this value is long enough. If you are only making pointing files the value can be reduced a little bit since the value found with this test is very conservative. If you have very long slew settle times you should tune your PID values of the mount (make it stiffer). Telescope Hysteresis Measurement What is Hysteresis Teelscope Hysteresis is a phenomena that reduces pointing performance and cannot be corrected by any pointingfile. As you know, pointingfiles can correct nearly all reproducible errors and the Autoslew software is powerful enough to fit nearly all errors we can think of. However, successfully applying a pointingmodel needs a telescope that has identical behavior during normal usage compared to the behavior during your pointing file. Unfortunately this will not be the case, and the reason is called Hysteresis. A simple example is when you are observing near the meridian and you came from the East side. Let s assume you have some mirror shift. Every telescope has some, if not, the optic is stressed. During the tracking the object will slowly move to the west but the man mirror will, at some point, also drift to the west side of the backlash in the cell due to the changed gravity axis. If your last object has been in the West instead, the mirror has already performed the drift towards the west side of the mirror cell and thus the outcome in tracking will be different from the first example. The Sequence Hysteresis measurement cannot remove this Hysteresis but it can measure it and thus gives you valuable information about the telescope performance and the expected telescope pointing performance. I know a lot of people that make huge pointingfiles without better result compared to a 4-star pointingfile because the major influence comes from Hysteresis. The Hysteresis measurement will give you an idea when to stop making bigger pointingfiles (because you will gain nothing more) and also helps you improving your telescope because now you can directly measure the problem. ASA Autopointing and LPT with Sequence04. 10/

20 How does it work? You can enter this screen in Functions / Measure Telescope. Sequence will make 5 exposures at the same Sky position (Altitude, Azimuth) in zenith and analyse them. The difference between the exposures will only be the part of the sky the telescope is coming from. So Sequence will slew the telescope to the Zenith and make a first exposure. It will then slew down to minimum Altitude to westerly direction (without taking an exposure), slew back to the Zenith and make another exposure. Then to the South, back to Zenith and making an image, then north, then a pier flip etc. The important thing to understand is that all these exposures are made exactly at the same declination and hour angle. This means at exactly the same encoder position. It completely eliminates any possible mount influence or mount or software error. So if you get large Hysteresis results, don t blame it on the mount. It CAN only be the telescope. If you have the [Measure Time Flex] checked then it will slew down to the given Altitude and Azimuth position and make exposures there (1 per Minute) for the given time (so 20 exposures for 20 minutes). What is Time Flex Time flex is a flexure of the telescope that does not have to do anything with the telescope position but only changes over time. Most people will be surprised that even if you keep the telescope at exactly the same position (thus the same encoder coordinate) there can still be a flexure issue. This can have several reasons, the 2 most important is Temperature effects When the temperature changes, different materials used in the telescope or the connection to the mount can bend the telescope or differences in thermal expansion coefficient between the mirror and the cell can cause the mirror to drift. Relaxation Effects Following a slew the telescope does not immediately bend/flex in the final position but needs some time to settle. The reason could be some soft materials (likewise used sometimes in a mirror cell) that needs some minutes to relax. Time flex is the worst of all possible errors since it cannot even be corrected with our new LPT. ASA Autopointing and LPT with Sequence04. 10/