Titan mount not tracking.

[Lester]

Hi all, it has been ages since I have used the Titan mount. So did a warm start, then star align on Procyon then set it to find Sirius and the computer pointed the scope down to the ground. It slews okay but doesn't track at sidereal rate, it is too slow.

The co-ordinates are correct for my location and the time.

Thanks for your advice.

[h0ughy (David)]

if you havent used it for a long while replace the battery in the gemini panel, then do a cold start

[pmrid (Peter)]

Originally Posted by Lester

Hi all, it has been ages since I have used the Titan mount. So did a warm start, then star align on Procyon then set it to find Sirius and the computer pointed the scope down to the ground. It slews okay but doesn't track at sidereal rate, it is too slow.

The co-ordinates are correct for my location and the time.

Thanks for your advice.

G'day Lester. Mine did that once and I found that the time zone setting had defaulted back to something else. I took the opportunity to renew the internal battery just in case.
Peter

[Lester]

Thanks David and Peter for your replies. I had the mount serviced by Brendan earlier in the year and he did replace the internal battery for me.

[Lester]

Time zone is correct at +9 .

[h0ughy (David)]

just cold start it then - i would change the battery anyway - but just cold boot it

[Lester]

Yep, thanks again David, will do that tonight.

[pmrid (Peter)]

Originally Posted by Lester

Yep, thanks again David, will do that tonight.

Lester, there's no need to wait until tonight. If you did a cold start now, just choose a star that you know - like say Shaula or Antares that will be half-way up the eastern sky and do a rough align on that. If it slews in the wrong direction again, it'll be pretty obvious.
Peter

[Lester]

Thanks Peter, will do.

[Lester]

Okay I did a cold restart of the Titan mount. Did a hypothetical alignment on Arcturus which is in the NE sky at present. Mount points to the SE, so about 90 degrees off from the true position. I began the cold start with the OTA in the parked position and scopes pointing south, counter weights in the down position.

Thanks again for your help.

[wasyoungonce (Brendan)]

Lester, just a question...it pointed ~90 degrees off the alignment star?.... or 90 degrees out after alignment star?

[Lester]

Hi Brendan, it pointed 90 degrees off the alignment star.

[wasyoungonce (Brendan)]

Lester can you just park the scope (any position) and then check it's running at sidereal rate or there abouts. Maybe park horizontal and check with inclinometer after an hr.

The last problem was bad "H" bridge, dead drive, but this is like it the Gemini divisors are wrong (thus it runs slow) or it is slipping at the oldham coupler or associated clamps?

I have seen one system not correctly counting pulses but this causes the system to run fast to keep up, thus usually something like this (slow) is oldham slippage or basic system setting are wrong?.

[Lester]

Brendan when I checked it last night it was running too slow in sidereal rate. I was wondering if there is an input in the set up that could be incorrect to cause this?

[wasyoungonce (Brendan)]

Originally Posted by Lester

Brendan when I checked it last night it was running too slow in sidereal rate. I was wondering if there is an input in the set up that could be incorrect to cause this?

When a Gemini battery is replaced the system defaults back to Titian mount settings and HGM lat/long time etc.

Can you use Gemini ASCOM to check these settings? Also check Gemini ascom and all other accessories are disconnected from the mount as when this is connected it can over ride mount defaults.

This does sound like a setting because if the system was running slow then you would get Ra/Lag errors etc. Currently the system thinks it's running ok, at correct Ra rate (although slow),....like it's counting too many pulses for given angular displacement.

[h0ughy (David)]

if the battery is dodgy and it defaults back your mount might just say its a titan - should it be a titan 50 you need to change that on the hand controller - sounds to me its on the wrong titan setting. this happened to me more than once and it will slew to the wrong position. change it to say titan 50:1

[Lester]

Okry this is going to sound dumb; but what type of Titan mount do I have? I changed the mount in the set-up from Losmandy Titan that has 6400 steps per rev to Losmandy Titan 50:1 that has 12800 steps per rev. Now it slews faster, have not been able to check the sidereal rate, if it is any faster. Could check that tonight.

Brendan the Gemini Ascom check did go way over my head, so I looked for a simpler fix. lol

[Lester]

Just read you post David, Thanks.

[wasyoungonce (Brendan)]

Lester I just sent you a word document to your gmail account on setting Gemini rates, divisors etc.

I also put in links to Paul Kanevsky's gemnini rate setter utility.

I thought you had a titan mount...but could be wrong

Hope this helps

[Lester]

Thanks Brendan, got it. I will see how the mount performs tonight. It's a pity Losmandy don't stamp their mounts as to what model each is.