Best way to guide my mount !

[Stu1976j]

Good morning all.

I was looking for a little advice on guiding my mount, I have a celestron CG5-GT mount and will be setting this up in my obsy within the next few weeks now but can't make my mind up on which route to travel down on guiding. now I can use a guide camera direct to the guide port on mount and connect via the hand set to the laptop /  PC or go down the route of having a good quality say webcam and run that direct to laptop and then connect the mount to laptop via a shoestring GPUSB and leave the hand controller alone. and best size for a guide scope ie: 50mm 60mm. 

I have read so much information on this subject now but would like to hear the views of people here who have maybe used both of these methods themselves. what are the pluses and minuses of each. You know what its like when you read so much online that you kinda loose the plot.

Any help / advice would be very much appreciated.

[alacant]

Hi. For me, the advantages and time saving at the telescope face with eqmod and a direct camera connection to PHD2 were the deciders. There are also fewer cables to go wrong and replace. Just my €0.02 HTH.

[spillage]

As above +1. st80 guide scope with mono webcam. phd2 and eqmod seems to work well for me.

[Cornelius Varley]

43 minutes ago, alacant said:

Hi. For me, the advantages and time saving at the telescope face with eqmod and a direct camera connection to PHD2 were the deciders. There are also fewer cables to go wrong and replace. Just my €0.02 HTH.

 

6 minutes ago, spillage said:

As above +1. st80 guide scope with mono webcam. phd2 and eqmod seems to work well for me.

Eqmod doesn't work on Celestron mounts.

[alacant]

13 hours ago, Cornelius Varley said:

Eqmod doesn't work

Ah, ok. Something similar then. Doesn't Celestron have an eqmod-for-celestron ascom layer?

[Waldemar]

My suggestion would be to keep things as simple as possible: Connect through PC or laptop, run PHD, do not use ST4 (not needed, just an extra cable that can cause havoc) and use an OAG  instead of guidescope, to get a grip on flexure differences.

AOG's with a possibillity to rotate the guidecamera 270° around the optical axis, so you will allways have acces to a guide star are plenty available. For example this one:
http://www.celestron.com/browse-shop/astronomy/astroimaging-accessories/guiders/off-axis-guider

[cjdawson]

I've recently been tackling a problem similar.  And here's the benefit of my experience and struggles.

Don't bother with those stand along autoguiders.  The problem that I've found (specifically the SynGuider II) was with finding a suitable guide star.   The camera didn't seem to be sensetive enough to be practical.

Get a laptop and dedicate it to asto work.  Install Ascom and use that to control the scope with planitarium software (I'm using Cartes de ceil) and PHD2 for guiding.

For my guide camera, I purchased a Starlight Express Superstar (mono), which is still waiting for first light.    It's got the ST-4 output built in, so there's no need for a shoestring adapter.

Also, you may be able to avoid the ST-4 connection completely and guide using the serial cable.

For my Meade LX-90, I prefer to use the ST-4 as it slews at 1/3 sidereal, rather than the 1* sidereal that the handbox uses.

 

My guide scope is a SkyWatcher ST-80, and I'm happy with that scope.  With my full setup, it's already picked up mag 8 stars without my trying to do anything other than grab a star image (testing the camera)

 

You might also want to take a look at the finderguider method.  I believe that this could work well.  But again, it's important to have a sensetive camera, so that you have no problems finding a star to guide on.

[Steve Ward]

Personally never had an issue with my Synguider , good for 30 minute subs with ease ( general limit of my ED80Pro+FF/FR - DSLR - HEQ5Pro - sky combination but have pushed it to 45 minutes in testing ) 

Only thing it doesn't do is let me take part in all the endless "Does this graph look OK ... ?" conversations on SGL ... 

 

( Using a 70mm Mercury 705 as the guidescope )

 

 

[cjdawson]

15 hours ago, Steve Ward said:

Personally never had an issue with my Synguider , good for 30 minute subs with ease ( general limit of my ED80Pro+FF/FR - DSLR - HEQ5Pro - sky combination but have pushed it to 45 minutes in testing ) 

Only thing it doesn't do is let me take part in all the endless "Does this graph look OK ... ?" conversations on SGL ... 

 

( Using a 70mm Mercury 705 as the guidescope )

 

 

Once the star was locked and the guiding was running, it was great.   The problem was with finding a star in the first place.  The Synguider was very unforgiving in that respect.  The only stars that I managed to get a lock on were Capella, Vega and one of the Pleiades.  Anything feinter and it simply could not see anything.   To add to that, the settings were very fiddly - one exposure time would show something, then the setting next door would show nothing.

After wasting hours trying to get a lock, I gave it up as a bad job.

My replacement setup addresses the issues that I had.  First, the Starlight Express Superstar has already shown me that it can see mag 8 stars, so this opens up the guide star opportunities by a very large margin.  Secondly, PHD shows me what the camera is actually seeing, so I can easily see to make adjustments to focus etc.    Third. PHD can do dithering, which is a feature that I didn't think about before as my old kit couldn't do that.   And finally, if I decide that something isn't working right, rather than replace the entire setup at the cost of £100's I can replace just the failing part with something better - would probably still cost £100's, but at least it's not a complete reboot every time.