Under contruction................
This is a simple guide for new owners trying to get their 416XT up and running quickly, it is not meant to be a definitive manual on all apsects of the 416XT but I will keep updating it. If anyone wants to add anything then just email me - I would especially appreciate your letting me know if you spot a mistake or think I've missed something out.
Opening the storage case for the first time reveals a confusing collection of camera hardware, an array of cables, new software to install, and the manual is not as helpful as it might be (and it's probably out of date too). So here's a rundown on connecting it all together, how to take your first images, and a trouble-shooting checklist if you're still having problems.
|
416XT CCD Camera connection diagram - see text for details. |
The 416XT offers two choices for getting the image data into your computer - either a serial (RS232) interface or a SCSI interface. The serial interface is obviously going to be slower, even using a fast computer and the maximum 115K bps it will take at least 20-30 seconds to transfer a full-frame image to your PC. The actual display time (from the start of the download to the image appearing on the screen) will vary according to the speed of your computer, a faster computer and graphics card will put the display up a little quicker so it's not possible to give exact download times. In the field I use a modest IBM ThinkPad 755C, it has a 256 colour display, and it's fitted with an Adaptec PCMCIA 1460B SlimSCSI adapter for connection to the camera. You will need at least a 256 colour screen (or shades of grey) in order to focus the image properly. I have used a serial connection in the past (before I bought the 1460B) but it is painfully slow, and I've not tried the serial connection on later versions of PictorView (V.6.nn onwards).
Power Cables: To power up the system you need a 12V supply, and a convenient source of this is a Gell Cell or Deep-cycle battery. You will need to make two power connections, one to the 416XT Controller box and one to the 201XT autoguider. Don't try using the standard LX200 power brick because that produces 18V not 12V, a brief over-voltage jolt will not actually harm the Control Box (I accidentally tried it!) but neither will it function at this voltage. When running, the camera setup uses about 2 Amps max - that's quite a lot of power but I've found a small 12Amp gell cell will work for 4-5 hour sessions, for all-night sessions go for a larger battery. Don't power anything up until you have made ALL other connections and checked them.
The SCSI Cable: The Control Box has a 1/4" x 20 threaded socket on the underside and will conveniently attach to a camera tripod - that's great for field use because you can place it where you want. The 1460B SCSI adapter came with a PCMCIA to 50-way Centronics cable, and this plugs straight into the back of the Control Box. This cable was a bit on the short side so I bought an extention (about 2 meters) to lengthen it.
Camera Data Cable: This cable is the long black one with the straight DIN-type plug on one end and right-angle plug on the other. This connects between the socket on the back of the Control Box and the camera body, the right-angle end plugs into the camera. This lead must be connected all the time the camera is powered up, the Control Box supplies power to the cooling chip inside the camera and it receives information from sensors in the camera about temperature of both the CCD chip and camera body itself. Without that connecting cable the control box ends up trying very hard to cool nothing at all - it's trying to push a current through an open circuit and it will overheat as a result. It's no disaster for the cable to be disconnected for brief periods, but extended periods may (will) cause damage. Once powered up there is a warning system should this cable become disconnected for any reason, the Control Box will beep and display the warning 'Head Disconnected', plugging it back in restores function without having to re-boot the camera. Try to route this cable through the forks and back around so that if it does get pulled for any reason it's less likely to get disconnected, if running your telescope and CCD camera remotely take a more positive approach and firmly secure the lead to the camera body with nylon cable ties. Another point, you want to avoid the camera cable pulling on the OTA as this will seriously affect the tracking - even the weight of the cable alone is enough to deflect it (don't believe me? try putting a high-power eyepiece in and then droop a coil of cable across the back of the scope). So, form a loop of cable long enough to allow the scope to point in any direction (3 feet or so) and attach the cable at that point to the wedge (not the forks!).
If you are using the serial link to get the image data in (rather than the SCSI link) then you will need to connect the supplied serial cable between Control Box and a free COM port on your PC. If you go this route you will find that not only do the download times increase but you might quickly run out of COM ports! I strongly advise you to use the SCSI link unless you have a very good reason not to (e.g., the serial link will allow use of a much longer cable, or your laptop simply won't accept a SCSI host adapter).
Telescope Control Cables: These are the serial cables that enable pointing control of an LX200 SCT telescope, and thereby also some of the auto-functions (auto-mosaic). To avoid confusion just connect the cable between the COM1 port on your PC (assuming you have PS2 Mouse and this port is free) directly to the RS232 socket on the LX200 and skip to the next section, but note that you will need to use the latest version of PictorView (6.43 release version or 6.44 beta) to make this configuration work. If you really like getting tangled in wires then read the note (1) below and the later section on Concurrent Use of a Planetarium Program.
The 201XT autoguider supplied with the 416XT kit works independently of the main camera, it has it's own power supply and a single cable (grey) that connects between the 201XT and the CCD socket on the LX200 front panel. For a first attempt I would advise leaving the 201XT on one side until you are quite happy that the 416XT is functioning correctly, no point in adding complication at this stage.
My personal preference is to always use the latest versions of PictorView (6.44b or the soon-to-be-released 6.45), later versions have significant revisions compared to earlier versions and many bugs in the program have been resolved. The latest release version, and also the beta releases, can be obtained from the Meade website.
Under Windows 95/98 installing the software is very easy - just run the install (setup) program and choose the directory where you want the program files stored. If you already have an old copy of PictorView on your machine I recommend uninstalling it (you can make a backup first - including the Pictor.ini file from your Windows directory) and then install the new version. This procedure will ensure a corrupt INI file is not produced during the install process. The install program will also add entries to the SYSTEM.INI file in your Windows directory to load a device driver (Wcsccdrv.386).
Start the program after installation, and go to File/SetUserPreferences, and for a SCSI connection check that the device I.D. is set to #4. This is the default, and whilst it can be changed by using the keypad on the Control Box, it's probably best to leave it set at #4 unless you have another device on the SCSI chain set to this number.
If you have an electric focusser (and wish to try the auto-focus routine), and you also have more than one COM port available on your computer, check the box at bottom right and select the COM1 port - you will then connect a lead from this port to the RS232 socket on the LX200. (note that even if you are using a SCSI connection - in which case the serial parameters for getting image data in listed above the SCSI I.D. box are apparently irrelevant - you cannot select the same COM port for both the electric focusser and the serial data connection, you will get a 'Port Sharing' fault reported. If you only have one serial port on your laptop and are using SCSI set the port ID in the 'Camera Settings' to a non-existant port (e.g., COM4) and the port for the focusser to COM1.
For the FITS version select 1.2, PictorView can read files saved as either V1.1 or V1.2 format but other programs may only read one of these. You are probably safer with version 1.2 (I do know that the Photoshop/PaintshopPro FITS Plugin is quite happy with version 1.2 files). If your third party image processing package has difficulty with Pictor FITS files then try loading and re-saving as V1.1 to see if that fixes the problem.
Select the drive/directories to store image files and callibration files (you must have created these in advance), and set the default camera temperature to -10 deg (this can be changed later). Finally, make your selection of the system defaults from the lefthand list of checkboxes, these defaults merely control how the software displays the image once it has been downloaded. The 'Sticky Enhancement' is a feature I specifically asked for - it retains the level/contrast settings from one image to the next as they are taken (does not apply to images loaded from disk), I think you will find this useful so I suggest you check it for now and change it later if you don't like the way it works.
In this dialog box you can also fill in details about image information, these default entries will be written to the FITS file header for each of your images which aids identification later.
Now choose File/FieldOfViewCalculator, and in the upper 3 boxes fill in the details of your telescope's focal length. Note that the focal ratio is automatically calculated from aperture and focal length, although if you enter a value for aperture followed by focal ratio (e.g., by entering 6.3 if you are using a focal reducer) then the focal length will be automatically updated. The information in this dialog is used to calculate how far the telescope must move to (for example) center an object on the chip, and also to calculate the movement required to produce an overlapping mosaic (the auto-mosaic function). If you change focal length then remember to change the values here too. You can even use this function when using the 416XT mounted piggy-back with standard 35mm camera lenses, just make sure the focal length is correct (e.g. 135 for a 135mm lens) and ignore the settings for the focal ratio and aperture. You'll find PictorView will be able to center objects and create mosaics in this mode too.
If you are using a serial connection for the image data, then instead of selecting SCSI ID#4 you will need to select the COM port used for the data transfer. This refers to the serial cable connection between Control Box and PC. You will also need to set the baud rate, and for a trial run I would suggest a very modest but reliable 38.4bps - this will be slow but good enough to check your setup, faster speeds (up to 115k) can be tried later after demonstrating everything else works.
Those are all the initial settings required to start taking images with the 416XT.
You should now be ready for a full power-up test of the system, this won't produce interesting images but will check that everything is connected in the right places. A good idea (when the tests are complete) is to attach large colourful labels on the ends of each cable so you can quickly re-assemble the system - even in the dark - without getting confused. Stick bits of fluorescent tape around the cables so you can see them and are less likely to trip over them in the dark (why do they insist on providing BLACK cables for astro equipment?)
Before you switch anything on, first check that that the LX200 is setup as usual (that is, if you are using an LX200 of course!) and the following cables are securely in place:
(Alternatively - a serial data cable connected between the Control Box and the COM1 port on the PC - in which case the serial telescope control cable will have to plug into COM2 - if you have one.)
The sequence of events are:
The options here reference the latest versions of Pictor.exe, this paragraph will be updated as new versions are released.
Multiple Configurations:
It's possible to use more than one INI file with PictorView, at the small expense of having additional copies of the .exe file on your hard disk. The .ini file (pictor.ini) is stored in the \WINDOWS directory so under normal circumstances only one configuration file may be used at any one time. However, on startup Pictor.exe looks for it's associated .ini file using the name of the executable for reference - i.e., if the executable is named pictor.exe then upon startup it will look in the /Windows directory for a file called pictor.ini. You can take advantage of this behaviour by having a copy of the .exe file with a different name (still in in the \PictorView directory) and another .ini file of the same name in the \Windows directory. For example, I have the following pair:
Windows Directory PictorView Directory PICTOR05.INI PICTOR05.EXE PICTOR10.INI PICTOR10.EXE Plus the default: PICTOR.INI PICTOR.EXE
The advantage of having multiple configurations are two-fold, firstly, it will be safe to experiment with one setup knowing you still have a working version immediately accessible to you should your experiments render one version unusable, secondly (and more important) it allows you to customise the base settings - particularly SCSI timings - for different exposure times. These are covered below.
IMPORTANT NOTE: Recent painful experiments have revealed that, whilst the default parameters are loaded from the appropriate *.INI file on startup using the technique described above, several parameters are read from the INI file during runtime. In particular, whilst any changes you make to the optical configuration (File/Field Of View Calculator) are written to the correct INI file, at runtime these parameters are read back from PICTOR.INI and NOT from the duplicate *.INI file. What does this mean? Well, Auto-Center and Auto-Mosaic use these parameters to calculate the slew distance, and if these don't match from within PICTOR.INI then the slew distances will be wrong. If you have PICTOR.INI set to f/10 (for example) but are executing a file called PICTOR05.EXE and have PICTOR05.INI set to f/6.3, even though it appears correct from the FOV calculator the values for an f/10 telescope will be used.
SCSI Timing Options:
SCSI operation of the 416XT are slow with the default settings, with frustrating long delays in the transfer of images to the PC. It's possible to speed up the data transfer by changing the settings for the SCSI timing delays which are stored in the .ini file Acceptable timings are very dependent upon exposure time, so there is no single set of options which are ideal for all circumstances. (It beats me why these cannot be set dynamically by the program at run time based on the selected exposure settings, but they are not so you have to set default entries in the .ini file). There are several parameters which set these minimum delays, and the default entries for the items of interest are listed below:
[SCSI Settings] SCSI_DELAY_TIME=8000 SCSI_BIN_DELAY=5000 SCSI_FOCUS_DELAY=1750 SCSI_DELAY_FACTOR=15 SCSI_MIN_DELAY=350
All but the SCSI_DELAY_FACTOR are in milliseconds, and they allow fixed periods for various procedures to complete. Some of the parameters are inter-related and you need the following ratio to be approximately true:
SCSI_DELAY_TIME = SCSI_DELAY_FACTOR * 393 + SCSI_MIN_DELAY
The SCSI_DELAY_TIME=8000 means there is an 8 second delay allowed before transfer of data can start, and this delay is longer than necessary for short exposures. For exposures of 5 minutes or less you can use a value of 3000 here, and for 10 minutes a value of 6000 is sufficient. If you set these values then you need to adjust the value for SCSI_DELAY_FACTOR to compensate so that the ratio remains true. The two .ini setups I have are for 5 minute and 10 minute exposures, and their entries are as follows:
For 10 minute exposures [SCSI Settings] SCSI_DELAY_TIME=6000 SCSI_BIN_DELAY=5000 SCSI_FOCUS_DELAY=1750 SCSI_DELAY_FACTOR=15 SCSI_MIN_DELAY=350 For 5 minute exposures [SCSI Settings] SCSI_DELAY_TIME=3000 SCSI_BIN_DELAY=5000 SCSI_FOCUS_DELAY=1750 SCSI_DELAY_FACTOR=7 SCSI_MIN_DELAY=350
Feel free to experiment on your own setup, it's likely you can tweak these setting further to reduce delays to the minimum.
Upon power-up the control box will display the version number of it's firmware (mine listed V3.00 when it was new about 18 months ago). With the latest releases of PictorView you will also get a new V.3.10 of the flash (ROM firmware upgrade for the camera Control Box), and you will need to install this for WIN 95/98 operating systems if you intend using V6.nn releases of PictorView. The firmware upgrade is done through PictorView, with Control Box and Computer connected with a SERIAL cable (so even if you normally use a SCSI connection, for this procedure you need to use the supplied serial cable). To perform the firmware upgrade follow this simple procedure:
Many people want to use their favourite planetarium program to control the telescope from the keyboard (I use SkyMap Pro 5, although TheSky, Guide, or Bob Denny's sophisticated ACP telescope interface all fall in the same category), but there is a problem in that both PictorView and SkyMap both want to use the serial connection to the LX200. Even assuming you are using a SCSI connection for the transfer of image data, that means you need two serial connections active at once (one for PictorView and one for SkyMap). Whilst it's conceivable to start and stop the SkyMap to issue commands via PictorView (for example, to auto-center your object) this is very inconvenient as SkyMap loses it's synch and the whole process becomes a pain.
However, there is a solution to this problem. As it happens there are actually two fully functional and independent serial ports on the LX200 - but these are rather inconveniently combined within just the one socket. You can only access the additional port by making up a special cable, but it's well worth the effort of doing so. Rather than making a Y-cable I got around this by making up a short cable which led from the LX200 socket into a small box, and inside this box I separated the individual wires and soldered them to two standard 9-pin D-sockets. This gives easy access to both serial ports using standard serial cables. The pin-out for the two serial ports on the LX200 can be obtained by using this link (http://www.austin.cc.tx.us/astro-ES/AstroDesigns/MAPUG/Battery2.htm#anchor2189857) - There's a colour diagram somewhere but I don't have the link to hand - I'll update this when I find it.
This is probably the most problematic part of the 416/616 CCD system, primarily because SCSI is not the 'Standard' communication protocol it was once heralded to be. Over the past few years it has been expanded and enhanced, new commands and functionality have been added, speeds have increased (from 5 to 80Mb/sec), the number of data lines have doubled (the 'Wide' SCSI) and of course the operating systems are constantly changing. Add to this the number of different manufacturers of SCSI hardware and software drivers, the number of different SCSI devices that it's possible to daisy-chain together (with differing capabilites like SCSI-1, SCSI-2 SCSI-Ultra), then it's a wonder SCSI ever works at all. In fact, on my desktop it doesn't - I still can't get 3 of my SCSI devices to co-exist on one host adapter so I had to install two adapters! So don't place all the blame on Meade if you can't 'Plug 'n Play', recent developments mean SCSI communications are always going to be more problematic to setup than simple Serial communications, but these problems will usually succumb to reason and/or a Big Stick.
SCSI drivers are supposed to backwards-compatible, but in the computer industry development moves so fast that hardware becomes obsolete within 12 months, and sometimes support for older systems is lost or degraded. Enter the Meade 416/616 system. Exhaustive testing was done only on a limited range of SCSI host adapters, and this testing was run using the (now) fairly old drivers around at the time. Testing continues even now but it is definitely possible to get caught out with an incompatible combination of hardware and software. In particular, Adaptec changed their driver at one stage which removed a crucial function used by the Pictor cameras and a result it failed to connect correctly. This problem was addressed by a later release of the driver which re-instated the missing software command. The ideal situation is to have a modest (inexpensive) computer entirely dedicated to data capture using the CCD camera, this computer can then to optimised for reliabilty as it does not have to perform multiple tasks. A much worse situation (but perhaps unavoidable) is to use your powerful, new desktop computer which is stuffed with all manner add-in cards, is loading a huge list of drivers (TSRs) for software that you don't use too often, and has other SCSI devices attached (like CDROMS, Scanners or Tape devices). It's clear that the chances of some incompatibility showing itself is far higher in the second example.
For the utmost in reliabilty use a stand-alone PC to control your Pictor CCD camera which meets these requirements:
If you are having trouble getting the camera to connect via SCSI then there are a number of things you can check before reaching for the Big Stick.
©Chris Heapy 1997-1999.
 |
Back to previous page |