This website is the main online repository for unofficial information on Vixen’s Sphinx mount with Star Book. Although by no means exhaustive, I have attempted to draw together many of the frequently asked questions and the generally agreed solutions.

1. ASCOM Sphinx Driver (computer control)

Vixen only provide computer control of the Sphinx via the Japanese language Planetarium software Stella Gear. I have developed an English language driver that allows the Sphinx to be controlled from a wide range of software that supports the ASCOM standard.

My ASCOM Sphinx driver has its own web page here.

2. Cables and Sockets

The nine pin lead connecting the Star Book to the Sphinx is straight through with all pins connected.

Auto-guider

The auto-guider port can be configured as a normal ST4 compatible port or changed to support the Vixen AGA-1 auto-guider. Changing the configuration requires unscrewing the service panel on the back of the Star Book and flicking a dip switch.

LAN

This port is used to upgrade the firmware on the Star Book and provides computer control of your Sphinx via my ASCOM Sphinx driver. How you connect the Star Book to your computer dep ends on whether you have an existing network.

No network

If your network adapter does not support MDIX, you will need a network port on your computer and a special kind of network cable called a ?”cross over” cable.

Plug one end into your computer and the other end into the LAN port on the Star Book. After you switch on your Star Book, go to the About menu and note the IP address listed. Fire up the firmware upgrade software or ASCOM client software such as POTH (which comes with ASCOM) and enter the same IP address. You should now be able to talk to the Star Book from your computer.

Network

In this case you will need an available network port on your Hub or Switch and a normal network cable. Plug one end into your hub or switch and the other end into the LAN port on the Star Book. After you switch on your Star Book, go to the About menu and note the IP address listed.?

If your network has a DHCP server (often built into switches and routers) the IP address should look similar to the IP address on your computer. Fire up the firmware upgrade software or ASCOM client software such as POTH (which comes with ASCOM) and enter the same IP address. You should now be able to talk to the Star Book from your computer.

3. Comets

The Star Book is only capable of displaying/slewing to comets in its inbuilt database.

The Star Book is actually capable of displaying up to 20 comets. For some reason Vixen have chosen not to provide an interface to allow additions and changes.

2005-06-29 I have written software that allows 10 user specified comets to be loaded into the Star Book. Unfortunately the current firmware incorrectly ignores all the position information making this useless.

4. Display Issues

Brightness

Most users have complained about the Star Book display being too bright even on the lowest brightness settings. From firmware 1.0 build 18 the brightness settings are stored between sessions.

Vixen ended up providing an after market set of transmission reduction films which can be stuck to the screen to further reduce the brightness. Although Vixen and resellers try to charge for this (not Vixen America) you should strongly argue that the Star Book is pretty useless without it.

If you decide to solve this yourself, you should use neutral density film rather than red tinted film as coloured film will greatly reduce the readability of the colour display.

One user has also added a 3m privacy filter. As described by the maker, this filter uses patented microlouver technology which works like tiny vertical blinds. This restricts the viewing angle such that most of the light is directed directly outwards from the Star Book screen with much less lateral light escaping.

You may wish to experiment on whether the louvers should be vertically or horizontally oriented. The filter also needs to be cut to size and one filter should be enough to cover more than one Star Book display which may help defer the cost.

Objects

Despite touting a database of 22,725 objects, only a small subset of these can actually be selected for GOTO and manually slewing the telescope using the nudge buttons displays the names of Messier objects in the centre of the view but does not display the name of other objects such as stars and NGC/IC objects.

Horizon Line

*pending*

5. Firmware Updates

Firmware can be downloaded from the Vixen Global web site, or the Vixen Japan web site.

Note that Vixen tend to release updates on the Japanese web site well before making it available on the Global web site. However, the firmware update that can be downloaded from the Vixen Japanese web site includes all supported languages so can be used on any Star Book. Where the date the Vixen web sites are updated differ, each date will be shown separately in the table below.

At present, any version of the firmware can be installed over any other version without having to apply intermediate versions. Each new firmware update incorporates all the fixes from the previous versions.

Payware features

Although the Sphinx supports backlash compensation and autoguider support in the latest firmware, the ability to use these features requires the use of a software key which is acquired by additional payment to Vixen Japan that used to cost around $22 USD.

Although not entirely clear, these features are enabled by default (i.e. free) in firmware release 29. Based on a rough translation of the Japanese web site it appears that this feature was only enabled until the end of September 2006 however subsequent releases made these features available completely free.

Firmware releases

6. Polar Alignment Scope

The three legged obstacle obscuring the line of sight of the PAS has been criticised for blocking an unnecessary amount of light. Vixen claim this is to stop inquisitive fingers getting caught in the hole through the declination shaft but this could have been achieved in a more effective manner.

Illuminator in Southern Hemisphere

The Vixen polar alignment scope uses a printed graticule rather than an etched one. This coupled with an overly bright illumination led makes the PAS basically useless in the Southern hemisphere as the relatively dim stars in the reference constellation Octans are overwhelmed by the brightness of the graticule even on the lowest illumination setting. From yser reports, this is not a problem in the Northern hemisphere as Polaris is bright enough to overcome this problem.

At least one user has solved this problem by machining an adapter to allow the use of a Losmandy PAS with an etched graticule to be used.

2005-05-16 Vixen now have a fix for this that lowers the minimum illumination however this requires the mount to be returned to the dealer at your expense and is not considered a warranty repair.

This is a similar design flaw to the Display Brightness.

7. RA/Dec Stiffness

Stiff axes of rotation of RA and/or Dec seem commonplace with the Sphinx mount. If your mount is under warranty you should return it to your supplier with a request that the RA and/or Dec axes be loosened so the mount can be more easily balanced. You can also do this yourself but be aware this may void your warranty.

Declination axis

Remember you should only need to do this procedure once so a fair degree of caution should not be too onerous.

*pictures pending*

If you have the optional Dec clamping plate you first need to remove the two allen screws holding the clamping plate in position then lift it off.

The black ring, with two holes axially parallel to the Dec axis allow a tool such as a pair of dividers to be inserted to unscrew the black ring. Use a screwdriver as a lever between the limbs of the dividers if necessary.

You should mark the original position of the black ring using a pen or piece of sticky tape. Suggested movements are 1/16″ at a time, checking for desired looseness each time. Overdoing it will introduce errors of worm/pinion meshing. You can of course turn it back a little if you loosen it too much.

RA axis

Remember you should only need to do this procedure once so a fair degree of caution should not be too onerous.

Remove blue plastic cover at base end of RA axis.

Look inside and you will see a black ring. It is locked in position by a set screw on the outside edge of the black ring as shown in the picture. You should mark the original position of the black ring using a pen or piece of sticky tape. This photo shows how far I loosened my RA axis where 1 and 2 were originally together.

To loosen the set screw a 1.5mm allen key is required. You will need to further shorten the key so that the short end can fit into the small space available. Use this to unscrew the set screw several turns (or it will irreversibly damage the thread on the end of the RA axis).

Rotate the black ring a few millimeters using a pair of dividers or similar. You may need to use a screw driver between the legs of driver for added leverage but that wasn’t necessary on my mount.

Retighten the set screw (snug but not too tight or it will burr the thread) and check the movement in the axis. You may need to do this a couple times to get the right amount of play. Don’t make it too loose or you will introduce play in the worm which will make the behaviour of your mount very unpredictable.

8. RA/Dec Worm Adjustment

I was prompted to write this entry after my mount stopped slewing in RA, rendering it useless. In my case the RA motor was actively trying to spin but was motionless; a situation that would have lead to burn out if I didn’t intervene.

Apart from axis stiffness, another less common issue is tightness in the worm itself that results in the mount having difficulty slewing even when the OTA is well balanced, or strange periodic error curves. This is not an adjustment to perform simply because you think your mount could track more accurately!

Read all the instructions below before proceeding! This procedure will probably void your warrantly so proceed at your own peril.

You need to be completely certain that you have an issue with your worm tightness before making any of the changes proposed below, as maladjustment may seriously impair the periodic error of your mount and may even damage the worm.

The first step is to remove the blue plastic covers. If you look closely at the Sphinx logo plate you will notice that at one end the plastic has an open end through to the edge of the cover. Apply gentle pressure to the logo plate in the direction of the open end and the logo plate should slide off.

This will uncover two hex screws that need to be removed with an allen key. Do the same for both sides of the mount and remove the two blue plastic covers.

The next step is to remove the electronics assembly. This involves removing the two hex screws at the top left and middle bottom in the photo to the left…

… and the hex screws at the top right and middle bottom in the photo to the right.

?

You then need to remove the lock lever on the counter weight shaft (not shown) in order to get enough clearance to unscrew the cap on the end of the counter weight shaft. Pay attention to the orientation of the lock lever when you remove it and take care not to rotate the counterweight shaft lock as you may have trouble engaging the lock after you reassemble the mount. The electronics assembly should now easily slip out. Be careful as the wires are relatively short.

Declination axis worm

?Note that this picture shows the mount inverted to make the screws and counterweight shaft cap more obvious. You should make any adjustments with the mount in the normal position.

The Declination worm tension screw will now be accessible. Turn the screw clockwise to reduce the pressure on the worm. The two screws either side of this are used to balance the worm and may also need to be adjusted depending on how tight or loose the worm is.

If adjusting these three screws does not change the tightness of the worm, you may need to loosen the two hex screw facing up in this picture. This could be very problematic as these screws appear to be torque tightened.

It is recommended that you make this adjustment while there is power to the mount so you can test the adjustment by slewing in the declination axis using the Star Book controls.

RA axis worm

?I was not able to access the RA worm tension screw with a normal allen key due to the lack of space between the motor and the channel with the recessed RA worm tension screw in it. It may be possible, and would be highly desirable, to adjust this without removing the motor with a slightly shortened allen key which would allow the tension to be adjusted while there is power to the mount so you can test the adjustment by slewing in the right ascension axis using the Star Book controls. Alternatively the worm can be turned by hand to check for tightness.

The RA worm adjustment screw is harder to access may require the RA motor to be removed. The first step is to remove the RA motor cog shown in the picture above. There is a small grub screw in the side which must be loosened to allow the cog to slide off. Once the cog is removed you will need to remove the four screws holding the motor in place then carefully move the motor out of the way of the RA worm.

The RA worm adjustment screw should now be accessible. Turn the screw clockwise to reduce the pressure on the worm. The two screws either side of this are used to balance the worm and shouldn’t need to be adjusted in normal circumstances.

This adjustment will most likely have significant impact on the periodic error of your mount. You should conduct long term periodic error curves to confirm the mount is performing correctly.

When replacing the RA motor, you will need to ensure that RA motor cog is firmly fixed to the shaft. This means ensuring the grub screw in it is tightened sufficiently but not too tightly as otherwise it will strip the thread.

Restore all the removed pieces in the reverse order that they were removed and you should now have a more usable instrument. I recommend not replacing the blue plastic covers until after you have confirmed the mount is slewing and tracking correctly.

Thanks to Jim Stratigos and Pierre Franquet for their input into this article.

9. Slewing and Tracking

10. Star Book future

11. Wish list

Known Bugs and missing Features with latest firmware and hardware. Many of these have

subsequently

been addressed by Vixen.

12. Websites of Interest

Advocacy

Vendors