With connection issues with the TCF-S focuser becoming more frequent, and with the issue not resolved by using a new USB Hub (2018-10-28),  the idea of updating the TCF-S drivers came to mind.   Visit to Optec website ( https://optecinc.com/astronomy/downloads/tcf-s.htm ) indicated that latest version TCF-S Control Program and ASCOM Driver is version 6.0.6.   Checking showed that this latest version ( 6.0.6) was installed on my computer around 2018-10-08

Reading the vn 6.0.6 download information again it was noticed that for my particular version of TCF-S Control Box (Rev 3 or 4) the REQUIRED version of TCF-S Firmware is v2.40.  But checking the firmware version number on control box's LED during initialisation shows that it's firmware is 2.33 .

It is tempting to think that the connection problems might somehow be related moving to 6.0.6 whilst continuing to use firmware v2.33 (rather than the required v2.40) however records from Jan 2018, reveal that TCF-S driver was deliberately  upgraded from 5.4.2 (64 bit) to 6.0.6 (any cpu) with the expressed hope of solving the connections issues already present when using the former driver.

[ Cost of firmware upgrade to v2.40 using a user installable PIC chip is $25  (excl shipping and duty) ]

Querying the situation with Optec , their recommendation was to use the firmware upgrade to 2.40 and use the new Serial cable with integrated USB.

Alternate Plan
Current operation of the TCF-S focuser is performed using CCDSoft5's focuser connection, with the focuser set to "Optec TCF-S". It is presumed that operation of the scope is performed use 'raw' commands to the TCF-S control box rather than via the TCF-S ASCOM driver.   (It is noted that connections to TCF-S are not possible from the Commander program and from CCDSoft at the same time, which probably confirms that CCDSoft5 isn't using ASCOM driver which should support multiple connections)

WIth the possibility that the connection issues might be resolved by using ASCOM driver rather than CCDSoft's direct control the potential use of TCF-S Ascom driver from with CCDAp2 (Observatory Control Program) was investigated.

Connecting to the TCF-S Focuser via an ASCOM.DriverAccess.Focuser object, it was shown that the TCF-S values (Step position etc) could be accessed and that this was possible to have both this connection and the TCF-S connection from with the Commander program open at the same time.

Next steps would be to prove that Focuser can be moved using the .Focuser object, and then fully transfer CCDApp2 focuser control to using ASCOM connection rather than using CCDSoft's Camera object.

So instead of getting current focuser position using  "Camera.focPosition" (CCDSoft5), the position would be obtained using "objFocuser1.Position" (ASCOM).

A potential alternate way of operating the TCF-S focuser using CCDSoft5,  is to use the "ASCOM Focuser (FocusAPI) Plug-In for CCDSoft" (available from https://ascom-standards.org/Downloads/Plugins.htm ) in order to access the TCF-S ASCOM Driver that way.

Background
Operation of TCF-S focuser for focusing, for temperature compensated focusing and for filter focus offsets has been frequently failing part way through a session as connection to the focuser is seemingly lost.  

Access to the 'Optec TCF-S'  focuser is made via the CCDSoft5 camera object which uses direct (non-ASCOM) connection to the Focuser.     Various things to remedy the lost connection issue (e.g. driver updates, different USB Hub) haven't worked and since there isn't a fool proof method of restarting the connection without rebooting everything the problem is both frustrating and a showstopper for unattended operation of the observatory.

Aim
To operate TCF-S focuser through entire sessions without the connection being lost, thereby preventing operating outages and/or poorly focussed images.

Plan
Plan is to try to resolve the lost connection issue  by operated the TCF-S focuser using it's ascom driver instead of direct (non-Ascom) connection from CCDSoft5.  

Whilst this can be done by creating an ASCOM.Focuser object in my Observatory Control Program (CCDApp2)  and adjusting the references used for interfacing with the focuser's properties and methods an alternate method required no change to CCDApp2 program code is to employ the "ASCOM Focuser (FocusAPI) Plug-In for CCDSoft"  in order to access the TCF-S ASCOM Driver that way.

Installation of Plug-In
The FocusAPI Plug-In for CCDSoft   (downloaded  from https://ascom-standards.org/Downloads/Plugins.htm) was installed on Laptop9 (Observatory Computer) and Laptop10 (Development/General Computer). The plug-ins read me notes are copied below for information.


CCDSoft Focus API Plugin (FocusAPI) V1.0.4
------------------------------------------

THIS FILE (FocusAPI-ReadMe.txt) IS LOCATED IN PROGRAM FILES\COMMON FILES\ASCOM (on 64-bit systems, look in "Program Files (x86)")

The FocusAPI plugin provides CCDSoft with the ability to control focusers via their ASCOM standard drivers. With this plugin, you can use focusers not supported internally by CCDSoft but which have ASCOM drivers. Also, some focusers have ASCOM drivers that provide enhanced functionality as compared to that provided with the internal support in CCDSoft. You can use such a focuser via its ASCOM driver with this plugin.

One-Time Setup:

1. In CCDSoft, in the Camera Settings pane, set the focuser to 'FocusAPI'.
2. Click Settings to bring up the focuser settings dialog. Enter your preferred large and small step sizes.
3. Click Choose... to display the ASCOM Focuser Chooser.
4. Choose your focuser and click on the Properties... button to adjust settings.
5. Click OK on all dialogs.
6. Back in the CCDSoft Camera Settings pane, click Connect. CCDSoft should connect to your ASCOM focuser.

You will then have access to focuser movement in the CCDSoft Focus Tools pane, and @Focus should operate the ASCOM focuser.

After installation CCDSoft5 was set up to use FocusAPI as the focuser and pointed to the Optec TCF-S focuser using the ASCOM Focuser Chooser.

CCDSoft5 set up to use TCF-S Focuser via ASCOM

 Testing

Operation of the TCF-S focuser was tested using the FocusAPI connection, but whilst focuser position can be read, and focuser moved from either CCDSoft5 or my Control Program (using CCDSoft.Camera.focPosition), the temperature probe reading (using CCDSoft.Camera.focTemperature ) is unfortunately not implemented in FocusAPI.

With the temperature reading critical for temperature regulated focusing I’m therefore creating my own ASCOM object and will use that for operating the focuser (including access to Temperature reading). I will monitor things over the next few sessions to see if things improve..

- Latest ASCOM Platform (6.4 SP1) was installed on Laptop9 (Observatory Computer, Win7) and Laptop10 (Development/General Computer, Win10).
- The new platform replaced the previously installed 6.3 platform.

https://ascom-standards.org/Downloads/Index.htm
https://github.com/ASCOMInitiative/ASCOMPlatform/releases

Back to Top

CCDSoft Focus API Plugin (FocusAPI) V1.0.4------------------------------------------THIS FILE (FocusAPI-ReadMe.txt) IS LOCATED IN PROGRAM FILES\COMMON FILES\ASCOM (on 64-bit systems, look in "Program Files (x86)")The FocusAPI plugin provides CCDSoft with the ability to control focusers via their ASCOM standard drivers. With this plugin, you can use focusers not supported internally by CCDSoft but which have ASCOM drivers. Also, some focusers have ASCOM drivers that provide enhanced functionality as compared to that provided with the internal support in CCDSoft. You can use such a focuser via its ASCOM driver with this plugin.One-Time Setup:1. In CCDSoft, in the Camera Settings pane, set the focuser to 'FocusAPI'.2. Click Settings to bring up the focuser settings dialog. Enter your preferred large and small step sizes.3. Click Choose... to display the ASCOM Focuser Chooser.4. Choose your focuser and click on the Properties... button to adjust settings.5. Click OK on all dialogs.6. Back in the CCDSoft Camera Settings pane, click Connect. CCDSoft should connect to your ASCOM focuser. You will then have access to focuser movement in the CCDSoft Focus Tools pane, and @Focus should operate the ASCOM focuser.

---

ASI Camera Drivers (2018-10-31)

Latest ASI Camera Native Driver (v3.0.0.5) was installed on Laptop9 (Observatory Computer) and Laptop10 (Development/General Computer).
On Laptop 9 the driver replaced the previous installed driver v1.3.12.28 , which had be manually uninstalled first
On Laptop10 the driver was a new fresh install

Latest ASI Camera Ascom Driver (v1.0.3.22) was installed on Laptop9 (Observatory Computer) and Laptop10 (Development/General Computer).
On Laptop 9 the ascom driver replaced the previous installed driver v1.0.2.13 , which had be manually uninstalled first
On Laptop10 the ascom driver was a new fresh install

https://astronomy-imaging-camera.com/software-drivers

ZWO ASI 178MC Camera Properties with New Drivers (1.0.1.0, dated 2018-08-17) (the previous driver version was 1.0.0.4, dated 2014-11-24)

System Check ( post ASI Driver Installation)

Native Drivers

- Equipment Profile (ZWO ASI178MC) created to test use of existing native ASI Camera drivers for operating the ASI178MC camera
- Camera:  "ASI Camera",   Mount: "Telescope Simulator for .NET (ASCOM)"  (temporaily standing in for POTH.Hub)

- Quick Test:   Connection ok, Camera Imaging ok

- New Equipment Profile (ZWO ASI ASCOM Cam) created to test use of ASCOM drivers for operating the ASI178MC camera
- Camera:  "ASI Camera (2) (ASCOM)",   Mount: "Telescope Simulator for .NET (ASCOM)"

- Quick Test:   Connection ok, Camera Imaging ok

Aim
One of the key components for reliable unattended operation of the Observatory is robust autoguiding under automated control.

Current Situation
PHD2 software is used for autoguiding as it does the job well and can be controlled via OpenPHD2 communication (for turning guiding on before imaging a target, for monitoring the guiding performance during imaging and for turning the guiding off once a target has been completed).    PHD2 performance is good when the stars are well focused, but deteriorates badly when stars are out of focus with the tendancy of PHD2 to pick a very dim guide star / hot pixel and/or quickly lose star lock due to star mass changes.

Guiding uses a ZWO ASI178MC camera attached to a TS 80mm APO scope piggybacked on top of the main LX200 scope.

Up to now focusing of the guidescope has to be done by the manual manipulation of the TS 80mm APO scope's  focuser knobs whilst watching the looping image in PHD2 and observing the FWHM/HFD values associated with a guide star.       This is both tricky and not consistent with the intended move towards fully remote and/or fully automated control of the observatory (If star is a long way from focus it is particularly difficult to find focus from within PHD2)

To assist the process a motor focus with computer connected focus controller (Pegasus Ultimate Powerbox) will be added at the scope.  This leaves the issue that PHD2 doesn't have it's own facility for focusing a scope based on the images it captures.  Whilst remote control of the focuser, whilst watching the image &  FWHM/ HFD values in PHD2 is a step forward from , this is far from ideal.

Plan
The use of a second program (not yet defined) is needed to carry out the auto-focusing task either at the start of session or at any time during the session if focuser drifts beyond what standard Temperature Compensation can handle.

Up to now PHD2 has been set to use direct (native) connection to ASI Camera (ZWO ASI178MC). This precludes using another program being connected to the Camera at the same time or causes problems.  To get around this limitation it is proposed that connection to the ASI Camera is made via ASCOM Driver.

Proof of Concept
To test the plan a new PHD2 Equipment Profile was created  which was set to use "ASI Camera (1) (ASCOM)" whilst CCDSoft5 was set to use "ASCOM Camera" set to use "ASI Camera (1)".  Tests showed that it was possible to have both connections open at the same time and to take images from both PHD2 and CCDSoft5 provided that imaging wasn't performed at the same time.

If PHD2 was looping images and an CCDSoft5 made an attempt to take a frame, it was found that CCDSoft wasn't able to download the image, and the Image had to be aborted otherwise Camera would be stuck trying to download the image.  Similarly if PHD2 tried to loop images whilst CCDSoft was looping images both programs would have problems - CCDSoft would stall whilst trying to download an image, PHD2 would stall and timeout after 16sec of trying to take a frame.

A further test was conducted where CCDApp2 (Observatory Control Program) was also connected to "ASI Camera (1)", making a total of 3 connections to the camera     Whilst CCDSoft5 was looping images, CCDApp2 was able to successfully read a series of camera properties (Driver Information,  BinX, BinY, Gain, CCDTemperature).

[ Camera connection is made using the ASCOM ID:  ASCOM.ASICamera2.Camera.   It's not understood why ".ASICamera2." name is used for ASI Camera (1) ]

A key factor in successfully programming involving access to ASCOM drivers is to know the precise Properties & Methods to use for each NameSpace.   One way of getting an overview and detail is to use the DriverAccess Namespace pages on the ASCOM Standards website.

DriverAccess Namespace
NameSpace for ASCOM Driver Access is described on at
   https://ascom-standards.org/Help/Developer/html/N_ASCOM_DriverAccess.htm

 

Reliable telescope operation is critical to observatory operations.  Recent occurances of "ASCOM Utilities : Timed out waiting for received data" error message during sessions over the last 6 months present a showstopper for unattended operation of the observatory, as the dialog box needs to be manually dismissed before remedial fixes such as disconnecting/reconnecting the Scope from TheSky6 can be performed.

TheSky6 Error Message: "ASCOM Utilities : Timed out waiting for received data"

 

It is understood that the message appears when ASCOM is waiting more than 5 secs and it timesout.

Looking at the ASCOM Talk forum (IO Groups) and  'StarGazersLounge' forum a suggested fix for the problem is to run Autostar Garbage Collection to 'clean' the memory in Autostar ..e.g    https://stargazerslounge.com/topic/311415-help-meade-lx200gps-ascom-phd-issue/.  Andrew Johansen's MyScope program was highlighted as one particularly suitable tools for doing Garbage Collect. 

Autostar is understood to use a linked-list data structure, and does not erase old entries until a Collection operation is performed... eventually the time required to traverse a long long list of expired entries exceeds ASCOM's timeout of 5 secs. With a clean list, LX200GPS response time is under 2 secs)

Andrew Johansen's MyScope software can be found at http://members.optusnet.com.au/johansea/
Garbage Collection is found under 'List Data' / 'Menus' / 'Garbage Collect'

(Unfortunately I was unable to get the associated .hlp help file to be displayed in either Window7 or Window10. Some research online suggested viewing the .hlp help files might require  installation of  Windows Help program (WinHlp32.exe) for Windows 7" from   https://www.microsoft.com/en-gb/download/details.aspx?id=91  I tried this on Windows 7 machine but I still couldn't get the help file to display.

Arrival
Pegasus Ultimate PowerBox arrived today from AltairAstro and was quickly unpacked.  
(The accompanying Universal Motor Focus was missing a Serial Cable and will be sent to me later. Cable arrived o 2018-11-06)

Software
Powerbox-Setup-1.4.9 was installed on installed on Laptop9 (Observatory Computer) along with 3 ASCOM drivers:
Pegasus UPB Switch Setup 1.3, Pegasus UPB Focuser Setup 1.1 &  Pegasus UPB Env Setup 1.3

Powerbox Setup and the 3 ASCOM drivers had been already installed on Laptop10 (Development/General Computer) as part of earlier evaluation of the Ultimate PowerBox and its supporting software

(Software downloads from https://pegasusastro.com/support/).

First few days spent trying to overcome some initial teething issues and get it brought into operation and get its control integrated into my existing Observatory Control Program.

Pegasus Ultimate Power Box

The next few days were spent getting accomstomed with the PowerBox connected to Observatory Computer and other hardware (TCF-S focuser, SBIG Camera)
Problems with dropped connection to the PowerBox caused by a breaks in the cigar plug power connection and switching of COM Port to new COMP ports numbered were troubling to track down.  After a few days the system eventually settled down, and the scope was mounted on the LX200's right hand fork arm

A Motor Focus (PEG-MF3-MOTOR-UN) was fitted to the secondary scope on 2018-11-06 / 2018-11-07

 

Program Settings (Regedit)

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\Pegasus\UPB

serialport :  USB Serial Port (COM6)

 

Getting SID for current user name
In cmd.exe

$ wmic username where name = "Username" get sid

After changing A/C Plug positions in the observatory, power to the Observatory Laptop was accidently left off whilst Pegasus UPB (AutoDew On), SBIG Camera, TCF-S Focuser,  Pulsar Dome were running along with the Observatory Control Program (CCDApp2,  in monitoring mode) , TheSky6 and CCDSoft5 A Simulation Scope was connected instead of the running.  Observatory Dome was connected, as was a simulation Telescope.

After 2 to 3 hours the laptop's battery became depleted to the level that the laptop went into hibernation. When remote connection dropped out, a visit to the observatory was mode during which the power to the laptop was turned on again and the laptop allowed to resume from hibernation.

Initial throught was that after resuming from hibernation was that COM4 Port to the Ultimate PowerBox (UPB) will probably have swapped itself for a higher numbered port (similar to behaviour observed with the PowerBox during initial testing) , and the UPB software would have lost connection to the UPB Box.  But this was the not the case, UPB Software connection with the UPB Box was working fine.

Other parts of the system faired less well, in particular the connection to SBIG Camera from CCDSoft5, where attempts to reconnect to the camera would produce the error message  "SBIG driver:  Camera not found".   Deleting SBIG drivers and trying to install updated drivers didn't fix things.   Turning off all USB Port / Turning-On all USB Ports didn't fix things either. Eventually the problem was solved by Disabling and

After some problems with COM Ports on Observatory Computer (Laptop9) in recent days, including an issue with COM4 that was being used by a newly installed Pegasus Ultimate Power Box (UPB) ,  the existing set of ports was thinned down to just those being used by current observatory devices.

This was done by creating a new environmental variable "DEVMGR_SHOW_NONPRESENT_DEVICES" from   'System properties / Advanced / Environmental Variables / New' and setting it to the value 1 (one).  Then from Device Manager  goto View and toggle on  'Show Hidden Devices' .   All assigned ports whether connected or not will then be shown.

Any ports that are not needed  can be deleted by right clicking the port and selecting Uninstall.

COM4 >> COM6
The (FTDI) USB Serial Port used by UPB was then reasigned from COM4  to COM6 in case  earlier problems have been caused by conflicts on COM4.
This was done going to the 'USB Serial Port (COM4)'  Properties and going to 'Port Settings / Advanced' and selecting the required new COM Port from the list of available COM Ports, in this case COM6.

By a similar process the COM Port used by LX200GPS Scope was moved to COM10

Device		COM Port		USB-Serial Connection
-		COM3		Prolific USB-to-Serial Comm Port
TCF-S Focuser		COM5		Keyspan USB Serial Port
UPB PowerBox		COM6		USB Serial Port (FTDI)
Pulsar Dome		COM9		USB Serial Port (FTDI)
LX200GPS/R		COM10		Prolific USB-to-Serial Comm Port
-		COM13		Keyspan USB Serial Port

Other non-serial devices are

Device		Device Name		Type	Type		Note
ASI178MC Camera		ZWO ASI178MC Camera		USB	Imaging Device
ST-10XME Camera		SBG USB Camera With Firmware		USB	SBIG USB Devices

The addition of a Pegasus Universal Motor Focus Unit (PEG-MF3-MOTOR-UN) to my TS 80mm APO secondary scope in a part of a set of hardware upgrades to the Clair3 Observatory to widen it's capability for remote and semi-automated operations and increase its potential for fully unattended operations.

Key Points:

- The Motor Focus was bought from AltairAstro (UK) and arrived on 2018-11-01 (with its control cable arriving a few days later, 2018-11-05 )
 (the Unit came with a selection of different Coupling Cylinders, to use with different shaft diameters)

- The Motor Focus has a High Resolution Stepper Geared Motor Enclosure (Step Angle 7.5, Deg 120, Gear Ratio 1:120). It's gearbox has very low backlash and high torque suitable to focus in micron scale. The Motor Focus comes with a Universal Anodised Aluminium L-shaped bracket for fitting the motor focus to the telescope, together with a range of motors couplers and associated grub screws.  0.06 degree step size that can easily lift more than 6 Kg of payload. Maximum Speed  400   (? steps/sec)

- The Motor Focus is being installed on the Rack and Pinion Focuser of my TS 80mm APO refractor which is piggyybacked onto my main scope.   The 80mm refractor has several roles including guide scope, secondary deepsky scope, lunar scope & solar scope) . The scope is used with a ZWO ASI 178MC colour camera that is connected via USB3 cable back to the Observatory Computer.

- the Motor Focus will be connected via control cable to the RJ45 focuser port on the Pegasus Ultimate PowerBox  (UPB) which has an inbuilt stepper focus controller.  Controller supports absolute focusing and it stores the exact focuser position so it can be retrieved in the next observing session.

- The UPB Box is connected to Observatory Computer via USB 2.0 cable where focusing operations are performing using the UPB Control Program, or by my Observatory Control Program (CCDApp2) or other 3rd Party Client Program using ASCOM.

Installation

Installation began with an initial fitting (2018-11-06) in which the focus motor was fitted to the fine focus shaft.   This produces unsatisfactory results and the following the day (2018-11-07) the focus motor was refitted onto the coarse focus shaft, which worked much better.

Initial Fitting (2018-11-06)

The 80 mm scope was temporarily removed from the Losmondy style D-Rail that sits onto for my 12" LX200GPS/R telescope, and brought indoors for the fitting.  It was the intention to the fit the focuser to the shaft on the left hand side of the RAP Focus system, however in the event I couldn't find a way of taking off the single coarse focuser.   Unable to find a grub screw on the knob itself, a grub screen on RAP focuser base close by  looked promising . However loosening/removing the grub screw had not affect at all on loosening the focus knob.  Twarted by this, attention turned to the Dual Focus Knobs on the left hand side of the focuser, whilst these were removed fairly easily by loosening 1 grub screw on each. 

None of the supplied couplers allowed me to connect to the coarse focus shaft (not larger enough or insufficient shaft length to be attached) . After considering the situation I resigned myself into fitting the Motor Focus onto the fine focus shaft, though its not recommended as it makes focusing movements very slow.

After adjusting the Motor Focus Box's position on the L-Shaped adapter it was fitted to the RAP Focuser of the 80mm scope by means of the coupler and a bolt+washers on the base.

The scope, with installed Motor Focus, was then returned to its position on its Losmondy D-Rail (atop the 12" LX200 SCT Scope)

The direction of movement and a rough rate (steps/cm) was established by position stepping   (+vs steps  lengthen the tube (ie. focus out) and .  Focus was manually moved to a working maximum position about 5mm short of the absolute mechanical maximum and it distance recorded.  Focus was then manually moved to a working minimum position about 2-3mm short of absolute mechanical minimum  and again the distance recorded (to allow this the grub screws holding the coupler to the Focuser shaft was loosened, and then tightened after manual moves had been finished).   Using UPB Control Software the Focuser Position was set to 0 at the minimum working position.   Goto moves were submitted to move the scope to approximate half way point (200,000) and to working maximm position (400,000).  The min/max position were recorded in the UPB focus control tab.

'Position Limit'  checkbox was toggled on and an attempt made to move to position 100 steps beyond the max position.   Focuser followed the instruction and moved to a position 100 steeps greater than max position, rather than stopping at the max position point.  Evidently the  'Position Limit' can't be relied on in the current version  (v1.4.9 / Oct 2018) . The focus position was then moved to the half-way point 200,000 (taking around 8 minutes to make the move

Based on speed of 400 steps per second and entire travel of 400,000 steps, this corresponds to 16.7 minutes from Fully-In to Fully-Out positions.
Based on step size of 0.06deg,  one turn of 1:10 fine focus is 6000 steps,   one turn of coarse focus is 60,000 steps.    The entire travel corresponds to 6.7 turns of the coarse focus.)

Unless the speed of making focus adjustments are lowered it will be necessary to find some way of connecting  to the coarse focus shaft which will speed up operations by x10.   Reading some online articals / queries, it appear that this is possible.  Apparently the grub screw next to the single Coarse Focus Knob, acts as a cover for access to two other grub screws inside set 90 deg apart.
https://www.cloudynights.com/topic/522910-removing-single-speed-knob-on-wo-star-71-focuser/

Final Fitting (2018-11-07)

The 80 mm scope was again removed from its Losmondy style D-Rail, and brought indoors for the re-fitting the Motor Focus. This was for the purpose of moving the Motor Focus onto the Coarse Focus shaft rather than the Fine Focus shaft where it was initially installed.

The Motor Focus Unit as removed and the Coarse and Fine Focusing knobs (taken off during the initial motor focus fitting) were refitted.

Using the information in https://www.cloudynights.com/topic/522910-removing-single-speed-knob-on-wo-star-71-focuser/ the grub screw next to the single coarse focus knob was removed and then an allen key inserted to loosen two grubs screen on the focus knob, set 90 deg apart, which were holding the focus knob on the main shaft. The knob itself was then easily removed to review the 6mm diameter shaft. A 6mm coupler was then attached to the shaft using two grubs screw, (using the original grub screw portal to tighten them). The Motor Focus and L - shaped adapter plate were then slighted adjusted and the Motor Focus Shaft inserted into Coupler (but not tightened with grubs screws just yet) and bolt/washers used to connect the unit to the bottom of the RAP focuser.

Fitting of Pegasus Universal Motor Focus Unit to TS 80mm APO Scope
2.5" Rack and Pinion Focuser on underside of TS 80mm Scope (Motor Focus to replace single manual coarse focus knob)		Focus Knob Removed (Grub screw removed to access 2 hidden grub screws (90deg apart)  in the Focus Knob. Loosing these 2 grub screws allows the Focus Knob to be taken off the Shaft)
Selecting Coupler to Use (6mm shaft)		Coupler Attached
Attaching Motor Focus/Universal Bracket		Motor Focus Fitting Finished

Before tightening the grubs screws that will eventually firmly connect the Motor Focus Shaft to the RAP's Focus Shaft via Coupler, the manual knobs on the other end of the focuser can be used to quickly move the focuser without attachment to Focus Controller, in order to defermine & measure the mechanical minimum and maximum limits of the Focuser,  and to select safe Minimum (Inner) and safe Maximum (Outer) Limits Positions (see pictures showing these limits).  

- Mechanical Range of 2.5" RAP Focuser is 80mm (0.0 to 8.0cm from inner hard stop).  
- The selected Safe / Working Range is 72mm (0.3 cm to 7.5cm from inner hard stop)

Focuser was moved back to its planned Step 0 position, around 3mm outerside of the mechanical inner limit and the grubs screws were then tightened firmly to connect the shaft of the focus motor to that of the focuser by means of the coupling cylinder. After tightening the coupler the manual focus knobs shouldn't be moved by manual force in case of damage to the gears in the motor focus unit.

Selecting Safe Inner and Outer Limits
Tube at Absolute Minimum Mechanical Limit		Tube at Chosen Minimum (Inner) Limit around 2-3mm outside of the mechanical inner limit (this became the 0 steps position)
Tube at Absolute Maximum Mechanical Limit		Tube at Chosen Maximum (Outer) Limit around 5mm inside of the mechanical outer limit (this became the 40,000 steps position)

The scope, with it's re-installed Motor Focus Unit, was then returned to its position on its Losmondy D-Rail (atop the 12" LX200 SCT Scope)

Motor Focus Unit and TS 80mm APO (device attached to back of scope is an Orion XY Finder)		Motor Focus Unit and TS 80mm APO (night)

The Control Cable was then attached between the Focus Unit & the UPB Box. After powering up the UPB and checking that the focuser was still sitting at the planned Inner Limit, the UPB Software was used to set the Focuser position to 0 steps.     Because the focus motor is now sitting on the opposite side of the focuser to initial fitting it was necessary to select the 'Reverse Motor' option (so that positive steps increments would move the focuser towards the Outer Limit, rather than towards the Inner Hard Stop.  

Controls were then used to move the Focuser to the Outer Linit Position which was at 40,000 steps (for the initial fitting this was at 400,000 steps confirming that the fine/coarse focus shafts had a 10:1 turning ratio).    The Focuser was then sent to the 0 steps position at the maximum recommended speed (400 steps/sec) and timed. The time, 100 seconds (1m 40s),  was consistent with the expected travel time (40000/400).

Based on 72mm working focus range and 40000 steps , each step corresponds to 0.0018 mm and each mm corresponds to 555 steps. 

Calculation of the scope's Critical Focus Zone and articles covering coarse and fine focusing of the scope using the new Motor Focus Unit are covered in the notes for the next session (2018-11-07, S636)