Change from EQMOD to ST4 autoguide

[bamus]

Ok, here is my case.

My cat has damaged perfectly working USB to Serial adapter bought for a few pounds from ebay. So this time I have bought one from Amazon. They have sent me 2 instead of 1 ordered, so I thought happy days J Unfortunately I have wasted yesterdays clear night trying to get this adapter working on my netbook. Drivers seems to be installed ok, but EQMOD does not recognize port and I could not started imaging session.

Now I can take another risk and try to find different USB to serial adapter or use my new QHY5v autoguider to connect to the mount with ST4 cable bypassing EQMOD. Is my understanding correct? Do I need something else to do guiding (hardware/software? ). In PHD I think I have to choose in Mount Menu – On Camera and hit connect to mount button – is it all?

I know I will lose ability to control mount from Planetarium software, but in I am happy to use Synscan Handset only and use nebook for PHD and APT and forget about EQMOD.

Thanks

Adam

[Merlin66]

That's always a risk with usb>serial adaptors.

I only use KEYSPAN adaptors now.

If you set up the cable between the PC and the handcontroller ( and use the On camera ST4 settings and ST-4 cable between the camera and the mount) you can still control GOTO etc etc etc from your planetarium program.

I use this set-up with the NEQ6pro and Carte du Ciel to run my system.

HTH

[bamus]

Thanks Merlin for your replay. Keyspan adaptors seems expensive, but I guess they are worth the price. But if I can reduce amount of cables running between mount, telescope and netbook, I will not invest extra cash to buy good SERIAL to USB adaptor, as ST4 connection will be enough to do guiding.

On the other hand I will be missing EQMOD GOTO accuracy.

[steppenwolf]

EQMOD is so good, I'd seriously think about letting it go!

A USB to serial adapter of known provenance would be a good investment.

Alternatively, if you are OK with a soldering iron, you could buy a USB/RS232/TTL adapter from Farnell and make your own very neat solution:-

Part Num. Qty. ordered Product description Mnfr Part #

1740364 1 CABLE,USB-TTL,SER CONV,5V,WIRE-END; SVHC TTL-232R-WE

1849899 2 D SUB, RECEPTACLE, 9WAY, PIN; Connector G17S0910110EU

3938189 3 BACKSHELL, D, DIECAST, 9WAY; Connector B MHCCOV-9MEL

30 minutes with a soldering and off you go!

[bamus]

Most probably I will be returning to EQMOD, but for time being I will try how does it work with ST4 only.

I was thinking about that and I have got one question. If I am understanding right, PHD is taking declination of the star from EQMOD. Now when I will do ST4 only, how PHD will calculate corrections which have to be made without it?

[chrisshillito]

PHD doesn't take the star declination from EQMOD. All its calculations are done in terms of pixel movement so doesn't need to know the declination at all. At different declinations the star will move different pixel amounts for a given correction pulse but PHD learns about this during its calibration process (so always calibrate on the guide star you intend to use!).

With regard to EQMOD, If your new convertor happens to use "prolific" drivers then makes sure you have the latest ones installed (from the prolific website) .

Chris.

[bamus]

Interesting Chris, I was always under impression that declination is taken from EQMOD and that was the reason for no need to provide focal length of guide scope.

But actually it does make sense that calculation of pixel movement is enough, providing that calibration is done every time telescope position (in declination) has changed.