Here's a question for all you Gemini users. How do you get it to autoguide? I don't have a problem with my G11 as I only have the digital drive, but last night I tried to help a friend out with autoguiding on the Gemini and just couldn't get it to happen. Here's the autoguiding setup.
ToUcam in C11 (with a few FR to drop the FL to something manageable.) to laptop>Shoestring adapter to Autoguide port on Gemini. Result; using phd guiding the star wouldn't move during calibration.
From memory this is a V3 Gemini (has the Din plugs)
if you remember paul I have the V4 gemini and I couldnt get that to work wit hthesame setup at astrofest last year. i put it down to the drive binding but now I am not so sure. I think it is the cable setup and the commands from PHD
I would be 99% sure that neither of you had the Gemini in Photo or All Speeds Mode, unless it is in either of those modes, the guide star will not move.
Press and hold the MENU button, Photo Mode will be the first item, release the MENU button and you will be in Photo Mode.
Definately in photo mode John. Checked and double checked. Set it first by holding down the handpaddle menu button until the quick select came up and when that didn't work I went into the menus and selected Photo from there. Still didn't work.
I used a similar setup until recently (FS102 with ED80, Shoestring, Q-Guider etc) and never had any problems when the Gemini was in Photo Mode, have you tried using a longer calibration run or possibly a brighter star, failing that, have you tried a different cable .
The only other thing I can think of is a dodgey Autoguider Port.
Definately in photo mode John. Checked and double checked. Set it first by holding down the handpaddle menu button until the quick select came up and when that didn't work I went into the menus and selected Photo from there. Still didn't work.
Sorry, didn't relize that you were talking about L.3, what I said was for L.4.
About the only other thing I can suggest is having a look within the Setup Menu at the guiding Speed, normally the Gemini defaults to 0.5x Siderial, might be worthwhile checking to see if that is what is set.
Are you sure the Gemini has the round DIN motor cables, the earlier models had RJ45 connectors for the motors and a different version of the Autoguider Ports and didn't like straight TTL connections.
4.2.3 Connecting an Autoguider to an Older Gemini 4.2.3.1 Connecting an Autoguider with Relay Output
Autoguiders with relay outputs (such as the SBIG ST-4) can be connected to the Gemini
system directly. Simply connect one side of each of the four relay contacts to the
Autoguider input common pin, and connect the other side of each relay to the appropriate
direction input pins of the autoguider port. Cables are available for most compatible
autoguiders to plug directly between the autoguider and Gemini.
4.2.3.2 Connecting an Autoguider with TTL Output
The typical "open collector" output stage (e.g. the ST-7/8/9/10, user-modified ST-4) has
high impedance while inactive and pulls down the direction signals to a common ground
when active. This is exactly the opposite of the way the Hand Controller and autoguider
ports of the older version Gemini system work.
A relay (or optocoupler) decouples the switching device (the Autoguider) from the
controlled device (the Gemini), thereby avoiding a direct connection between the two
systems and protecting both systems against high currents that could cause damage. IMPORTANT NOTICE:
(1) Never connect TTL output stages directly to the Hand Controller or autoguider ports
of an older version Gemini! Severe damage may occur to the connected devices. Use a
Relay Box (as provided by SBIG) or the optional Losmandy Optocoupler unit instead.
By so doing, you get the additional advantage of providing electrical protection to these
sensitive units.
(2) The use of two separate power supplies without a coupler unit is strongly
discouraged. To do so would connect the ground of one system to the supply voltage of
the other system, causing the two grounds to be at different potentials. If the grounds of
the two systems are then connected, severe damage is likely to occur.
Detailed instructions for connecting an SBIG camera with TTL outputs to the older
version of Gemini can be found in Appendix 8.6 (Autoguider Port).
I should add to that, as far as I am aware, the Shoestring thingy is an Optocoupler anyway.
I should add to that, as far as I am aware, the Shoestring thingy is an Optocoupler anyway
That's what I thought as well.
I'll see if I can find a picture of the model of Gemini being used. But from memory it shouldn't need an optocoupler anyway. It's only about 3 years old.
I'd like, at some point in the future, to be able to use my ATiK 16IC with it as an auto guider. It is apparently ST4 compatible. Where would I get a suitable cable? Or do you know where to get a pinout diagram. I certainly wouldn't make it as what I know about electronics could be written on a pin head in 72 point font.
It seems odd that your not getting "Autoguider Error" coming up on the Hand Controller.
One thing I found was that you had to have the autoguider cable plugged in on startup, and, I don't know which Shoestring thingy you have, USB, Serial, Printer Port, if it was the Serial or Printer Port version, you had to start the computer before the Gemini, I know it is the complete opposite with the ST4K.
That is the older version of the Gemini, the new version has round DIN motor plugs.
Here is what the manual say's re Autoguider Error:
7.1.13 Gemini Displays “Autoguider Error”
•
This message indicates that Gemini received contradictory signals (RA+ and RAor
DEC+ and DEC-) at the same time. If this happens occasionally, it can be
ignored. Otherwise check the cable from the autoguider to the Gemini and keep it
as short as possible. Do not use a twisted cable; it could induce spurious signals
from one wire to the other.
PS: The battery is OK isn't it, they give all sorts of mischevious reading and errors.
Yep the battery has only recently been replaced. Lets make sure I'm using the right cable. I'm using the one bought from Shoestring Astronomy for ST4. Looking at the two ends, side by side, with the retaining clip upwards the colours of both ends go, from left to right, Blue, Ye, Gr, Re, Black, Wh. does that sound right?
I have another cable (for a remote controller for my Digital drive that is the opposite), Wh, Black, Re, Gr, Ye, Bl, at both ends, clip up.
Paul, I know even less than you re electrical things so I will past the relevant bits out of the Manual:
7.1.12 Autoguider Calibration Problems
•
Be certain that you are in Photo Mode or All Speed Mode. The autoguider port
will only work in these two modes. Make sure you have not left Gemini in Menu
Mode, and that you are using a tracking rate that is appropriate for your
observation.
•
Make sure you have the correct cable to connect the autoguider to the Gemini. Be
sure to use an Optocoupler unit or Relay Box (with appropriate cable) if you have
an autoguider without relays and an older Gemini (motor cables use RJ-45
connector). If your Gemini unit uses DIN connectors for the motors, you
can
connect TTL output autoguiders directly to Gemini. Refer to Appendix 8.6 for
more details.
•
If RA calibration works but Dec. does not, check the backlash in the Dec. gear.
Set the TVC or increase the autoguider’s hysteresis setting.
and:
8.6 Autoguider Port IMPORTANT:
There are two different versions of the Gemini Autoguider port
hardware. The versions can be distinguished by the type of connectors used for the motor
cables. The older Gemini version uses RJ-45 modular connectors, and the newer version
uses 6-pin DIN connectors. The primary difference between the versions is that the older
version does not directly support autoguiders with TTL output, but the newer version
does.
Both versions of the Gemini Autoguider port are plug compatible with SBIG model ST-4
and STV autoguiders.
This is the wiring diagram from some previous post:
Ok so it looks like I need to use either an optocoupler or a Relay Box with it if I'm using an ST4 style autoguider. Originally I was informed (by someone that should know) that I wouldn't need an optocoupler. I do have a relay box so I'll give that a try next time.
What about if I'm using my laptop to connect to the Autoguider port? That's the part that's got me really confused. If I run to the GPUSB then I shouldn't need an additional optocoupler, it should (as I understand it) run straight from the adapter with an ST4 type cable.
I can only go on what I found works, that was to have the Gemini on a completely isolated power source, laptop to another source, normal setup of Shoestring USB into the laptop, guidecable going straight from the USB thingy to the autoguider port, autoguider camera pluged into a USB port on the laptop running PHD, worked everytime without fail (and still does).
Personally, I don't believe you need a relay box or optocoupler, the GPUSB is already one of those.
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