Astrotrac Guiding not working

[Dave Shave-Wall]

Hi,

I'm trying to get the AT working with a Lodestar without much success. I have set a bunch of standard parameters as suggested elsewhere, but manual movement of the RA axis does not work, nor does the calibration move the star. The camera and cable work on my Paramount MEII ok. I have included the Log file below. Can anyone suggest next steps?

Thanks

Dave (Currently at 7,500ft on Mount Teide)

[bw_msgboard]

Hi Dave.  As you say, the mount isn’t responding at all.  What is the Lodestar attached to?   You’ve specified it’s something with a focal length of 50mm.  Is that really correct?  Or is it a 50mm aperture on something?  Because the specified focal length is so small, the calibration pulses are huge, nearly 10 seconds.  Perhaps the mount can’t handle guide pulses that large.  You might want to try the manual guide tool with different pulse sizes to see if you can get the mount moving.  Trying to do a calibration at this stage is just going to be a waste of time.  Is there anything that has to be set in the mount to support ST-4 guiding?

 

Good luck,

Bruce

 

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[John Sim]

Just to comment that I have been guiding an Astrotrac without any problems, there's nothing on the mount that has to be configured to enable ST-4 guiding. In my case I have a guidescope with focal length 280mm and the guidecam is the QHY5L.

[bw_msgboard]

Thanks for posting this, John, it’s a help to know that this is a workable set-up for guiding.

 

Bruce

 

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From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of John Sim

Sent: Friday, June 30, 2017 7:26 PM
To: Open PHD Guiding

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[Dave Shave-Wall]

Hi Jon,

Good to hear you have a working setup, the difference seems to be the guide camera. Can you tell me if the QHY guide cam is allowing you to use the original Astrotrac guide cable?

Thanks

Dave

[Dave Shave-Wall]

Hi All,

So I’m back at home (back up the mountain in 7 weeks time again. I have had some advice from the AT forum and been given some wiring diagrams to make a manual controller to test the guide port on the AT. I have successfully made a V-Align hand controller (care of Jim Waters diagrams) and it works a treat, so we know the AT guider port is working, it now allows you to speed up to 1.5x the rate and slow down to 0.5x the rate with the rocker switch.

Also to test I have replaced the AT with the Paramount ME II I have just to check everything, PHD2, laptop, camera, 50mm lens and Lodestar guider cable do work and this is positive so all ok there. However replacing the MEII back with the AT and no luck, it does nothing either on a star or on manual guide.

So, after some hard thinking we (myself and a friend of mine Bob) took another look and we believe we have found the problem. This is that the lodestar cable has a standard ST-4 RJ-12 plug with 6-Pin connector, NOT the 8-pin plug that comes with the AT guider cable. What is happening is when you plug the standard ST-4 6-pin Lodestar connector into the AT guider port the pins DO NOT align! We can’t believe nobody has noticed this.

So we have made (to test this) a connector that allows you to keep the Lodestar cable plugged into the Lodestar (since this is also a proprietary flat 5 pin connector), but allows you to then connect the standard ST-4 6pin RJ-12 (lodestar cable) to this adapter. The other side of the adapter takes the AT supplied ST-4 cable (normally plugged into the camera directly but cannot on the Lodestar due to the 5-pin proprietary connector) and thus allows you to then plug the other end of the AT supplied cable (8-pin NON STANDARD guider cable) supplied with the AT into the AT guider port. So far we have tested in the study focusing on a distant object and it looks like it works, however we need to test on a star to make sure we are correct.

So the real problem to this looks like the NON STANDARD 8 pin connector used on the AT that does not accept a standard ST-4 cable, i.e. it fits but the pins don’t align. Continuity testing on the pins has given us a positive feeling this is correct. Once we have tested on a star (cloudy last night, typical) I will come back with results and photos. If this is correct then if you have a Lodestar and are therefore forced to use the Lodestar cable you will need an adapter to convert the 6-pins ST-4 connector to the 8-pin AT connector!

Clear Skies

Dave

[Dave Shave-Wall]

Hi John,

Can you share your PHD2 settings for the QHY camera to work? What is the lens/scope it is fitted to? Are you using the AT guide cable that came with it straight into the ST4 port on the QHY? Can you use Manual Guide on PHD2 and watch the star move?

Thanks

Dave

On Saturday, July 1, 2017 at 3:26:06 AM UTC+1, John Sim wrote:

[John Sim]

Hi Dave

Yes, I use the AT guide cable to connect the QHY5 direct to the AstroTrac. Nothing special in PHD2 - choose QHY5 camera and Mount is "on camera". I haven't specifically tried the Manual Guide control but guiding, and dithering, undoubtedly works. Guidescope is the ZWO 60mm.

The only reason I'm guiding the Astrotrac is because I want to dither between subs. My imaging is with either a 400mm or 200mm Canon lens on a 700D with typical exposures of 2 minutes. Unguided the AT was very good (if the PA was good) but correlated noise, or "walking noise", was a problem that can only really be solved by dithering.

[John Sim]

Hi Dave

I've just noticed in another post a note by Bruce that there is a bug in the dev6 release that affects "on camera" guiding for QHY cameras - apparently guide directions are incorrect. It's been fixed in dev7. I haven't been imaging since April - no clear nights - so hadn't encountered it.

[Dave Shave-Wall]

Hi John, I thought I would report back. So I now have my setup guiding with a Lodestar, PHD 2 the latest version with the bug fix for recognising the camera and the Astrotrac. I can also guide with a QHY as you have as you can use the AT cable as the QHY accepts the ST4. The problem is the Lodestar has a proprietary connector and so to get it working I needed to buy a back to back coupler to connect the AT provided cable to the Lodestar provided cable. The link below is what I purchased. This changes connects the right pinouts as the Lodestar cable swaps the outside pins on their cable, My Paramount MEII is clever enough to fix this problem but the relatively dump Astrotrac is not. So I'm now happily gudiding with a 50mm lens :-)

http://cpc.farnell.com/pro-signal/31059r/cord-coupler-straight-wired-rj12/dp/TE05848

Clear skies

Dave

[George Z]

John, I came across this thread while searching for info to autoguide my Astrotrac TT320x-AG with a QHY5L. It should be pretty straightforward, but my challenge is that when I bought my Astrotrac, it did not come with a ST4 autoguiding cable, nor am I successful to find a shop that sells the cable. I can make certainly make a RJ45 to RJ12 cable, but I don't know the pin layout. Could you possible take a picture of the two connectors of your cable so I can see how the colored wires are connected? I assume pin 1 and 8 of the RJ45 are not used, but need to know if the remaining 6 pins are straight or flipped.

Thanks,
George

[George Z]

Dave, I wonder if you could let me know how the Astrotrac autoguide cable is wired from the RJ45 end to RJ12. My tracker did not come with a guide cable and I have been struggling to find one or get the pin layout info to fabricate one. If you could let me know where each of the 8 pins from the RJ45 side goes by matching the wire colors to the RJ12 side, it is greatly appreciated. If sending me pictures is easier for you, it is even better.

Regards,
George

[John Sim]

George,

I posted a diagram on the QHY forums in response to your post there. This was from the Astrotrac group on Yahoo Groups - not very active now but useful as an archive of user experience and tips for the Astrotrac.

The cable should be included, its part of the Astrotrac package. Your vendor is at fault if it is missing (unless you got it second-hand?)

cheers

John

[George Z]

Thanks so much John. I got the diagram you posted in the QHY forum. I don't believe the early TT320x-AG tracker came with the cable, but you could be right. I am happy now. Time to hit Amazon to order some parts to make the cable.

Regards,
George

[ch...@beyondmonochrome.co.uk]

My experience maybe the same as yours... I just bought a Fornax unit, which has an RJ12 to 3.5mm jack guider cable. Fornax assumed the ST4 standard from the original SBIG implementation. I found that my ZWO camera does not. The pins (1-6) are in the reverse order. When that occurs, the Fornax does not move. One way to fix it is to either make up a completely new cable, or just purchase an RJ12 coupler and a short cable that effectively swaps over the pin order.

I made a cable up to the ZWO pinout specification and it all worked.

regards

Chris Woodhouse