Off axis guider vs. guide scope

[Dirty Harris]

Dear Guylain, I am looking for some professional advice, from you or anyone else who has used either an off axis guider or guide scope, or both. Which would you recommend? I've heard arguments for both, but the off axis guider seems to help eliminate the diff/flexure that a guide scope has. What has been your experience? We run a Celestron CPC/SCT fork mounted 11inch monster, that does a super job on planetary, but we're hoping to get into some of that deep-sky stuff, and obviously we'll be needing to guide. Hope you or others have some info. Thanks again, Dirty Harris. Colorado, USA.

[astroman133]

I would try to keep the ratio of the resolution between the imaging train and the guiding train lower than 5:1. I know that some say that good imaging with a ratio as high as 10:1 can work, but IMO you may be expecting too much with that much difference.

 

There are a number of things that can be done to make piggy-backed guiding work to its optimum

 

1) hold the guidescope with a clamshell instead of 3-point rings (less chance of flexure),

2) use at least a medium quality guidescope with a good focuser that holds the drawtube solidly (again, to minimize flexure),

3) increase the guidescope focal length with a different scope, or put a barlow into the train (increase resolution),

4) use a sensitive guide camera with smaller pixels (increase resolution),

 

There may be more steps that can be taken...Chime in with your ideas!

[s3igell]

One of the best Upgrades for a Guidescope is to replace the "cheap" Rack&Pinion or Crayford Focuser with a Helical Focuser (around $75-85).  This will reduce any question of Flexture in the Focuser (especially with ones that C-Thread or T-Thread to the Camera).  And...  Guidescope / GuideCameras really DON'T require many Changes in Focus (set&forget).

Other than this, use Clamshell or Scope Rings rather than the 3-Point or O-Ring Mounts (best left for FinderScopes) - as Rick advises.

[dts350z]

and...

 

Adding a barlow is a great way to cause flexture (unless everything is threaded and screwed together.

[Dirty Harris]

Thanks to all for your input. s3igell, I had no idea that a PHD-2 guider could get 1/10 th pixel capability, that is tremendous, may just look into that. And again, Astroman 133, thanks for the info on the optical train ratio, that's just about where I'm at with my set-up about 5:1. We usually use the Telvue 2.5x or 5.0x barlow right on the front of the camera. Many of you spoke of a good quality guidescope if I choose to go that route would you have a particular name brand that you would endorse? Again, thanks for the knowledge and wisdom, and for sharing it with other newbies like me. Dirty Harris. Colorado.

[s3igell]

For your CPC1100 (less any Barlow for Planetary), the Orion ST-80 f/5 + ASI120MM would work quite well.  Else the Celestron 80mm f/7.5 will work for even longer 600mm FL - and both are about as light as Refractors get...

[astroman133]

I used an Orion ST-80 as a guidescope for a while but there was too much sag in the drawtube.  I replaced it with an AT-72, which I really like. It has decent optics and a 2" dual speed focuser.  It doubles as a white light solar scope.

[jimwc6491]

anyone.

I just upgraded to Win 10. I have not had any problem except for my StarShoot AutoGuider. it is not Win 10 compatible.

I was wondering if the Starshoot G3 DSCI would work with the latest version of PHD2.

any other suggestions on a good Guide camera that will work with Win 10.

 

also what is the rule of thumb for a Guide scope to main scope size?

[s3igell]

Why do you say that your SSAG is not Win10-compatible??

 

Numerous people report SUCCESS with just that Camera, over on the PHD2 Support Site - OpenPhdGuiding Google Group.

[astroman133]

Compatibility of the Starshoot G3 with Windows 10 is a question for Orion.

 

Compatibility of the G3 with PHD2 is question for the PHD2 discussion group.

 

There is no good rule of thumb regarding relating imaging scope size to guidescope size.  I assume that when you say "size" you mean "focal length".  It is more complicated than that, since you also need to consider the relative pixel sizes of the guide and imaging cameras. Given a focal length of the telescope and a pixel size of the camera it is simple math to calculate the resolution of the optical train, in arc-seconds per pixel.

 

When the pixel size is in microns and the focal length is in millimeters, the formula for calculating the angular size of a pixel in arc-seconds is:

 

206.265 * pixel size (in microns) / focal length (in mm).

 

So the resolution of a C-11 with a Canon T5i is 206.265 * 4.3 / 2794 or 0.317 arc-seconds per pixel.

 

As has been said previously in this thread. Claims have been made that PHD will guide with a ratio of the resolution between the imaging train and the guiding train as high as 10-to-1.  I would suggest that you should try to stay below 4-to-1. Remember that the small the resolution value, the higher the resolution, so the target resolution for the guiding train would be around 1.27 arc-seconds per pixel.

 

Selecting an AT72ED, with a focal length of 432mm as a guidescope means that in order to maintain a 4-to-1 ratio in resolution with the above imaging train, the pixel size of the guide camera must be no larger than 2.65 microns.  Or if you choose a ZWO ASI120 (3.5 micron pixels) the guidescope should have a focal length of at least 540 mm to maintain the 4-to1 ratio.

[jimwc6491]

s3igell

Thanks

 

By not compatible I mean that the Orion StarShoot AutoGuider is not combatable with Win 10 per Orion Tech Support, no drivers, they just now got the Win 8 drivers.

I fear that they will not get a Win 10 driver for another month. and it still will only be compatible with PHD2 v 2.2.1 

it is also only compatible with PHD2 v 2.2.1, PHD2 is up to v 2.2.5 there were a lot of good changes in the versions between 2.2.1 and 2.2.5.

 

the StarShoot G3 DSCI is compatible with Win 10 and uses ASCOM to interface with PHD2.

 

Ill check on the PHD2 support site.

[jimwc6491]

Rick

 

Thanks

 

I think your resolution ratio info was what I was looking for.

I know the G3 is compatible with Win 10 and I think it is compatible with PHD2 via ASCOM.

I was just wondering how this would work with BYEOS.

[astroman133]

Jim,

 

No problem.

 

I have a friend who has been using a SSAG on Windows 8.1 with PHD 1 and 2 for several months.  It also seems wrong that PHD would stop supporting the SSAG with releases after 2.2.1.  I am pretty sure that my friend has a newer version than that.  I am up to 2.3.1, but don't have the SSAG.

[jimwc6491]

Rick

 

its not PHD not supporting it, is Orion and their windows drivers for the SSAG. they just now (with in the last month) came out with there win 8 and USB 2-3 driver.

 

I am looking for a guide camera I can use that is win 10 compatible and has decent support for windows and keeps there drivers up to date in a timely manner.

[s3igell]

There is nothing in the current progression of PHD2 Releases upon which a specific SSAG Driver would be dependent.

 

The Orion Website is simply NOT Keeping Up with the Rapidity of PHD2 Releases!!

[dts350z]

I use phd2 2.5dev5 with SSAG on one rig.

 

Right now the dev releases have all the new cool stuff. New GUI, new tools, etc.

 

http://openphdguiding.org/development-snapshots/

 

You can use SSAG either native or ASCOM.

[jimwc6491]

S3igell

 

I am aware that PHD doesn't need a driver, but the camera does. if there is no camera driver the camera wont work under windows. it might still work via ASCOM.

Orion is not keeping up with there windows drivers as well as the PHD revisions.  

[jimwc6491]

dits350z

 

will the SSAG work with PHD and allow dithering in BYEOS. If so please send me the setup.

[dts350z]

Both my imaging laptops are running windows 7. Perhaps that is why I don't have any difficulties with SSAG drivers?

 

Yes, PHD2 and backyard eos can do dithering with the SSAG. Dithering has more to do with the mount than the camera, however. I'm using EQMOD, the ascom driver for Orion/Syscan mounts, and I do ascom pulse guiding, but ST4 guiding will also work and dither.

 

Not sure what "setup" you want. I use the profile wizard in PHD2 to setup the hardware. 

[jimwc6491]

dts350z

 

I'm sorry I should have said setup in ASCOM for PHD and BYEOS. setup for ASCOM.

I tried to connect PHD to my SSAG via ASCOM and I got a driver error. yes I am sure I installed the ASCOM driver.

 

yes I had no problem with Win 7 or 8 its Win 10 I'm having problems with.

[astroman133]

Jim,

 

When using your SSAG with PHD for guiding, you would typically select Starshoot Autoguider as the camera, not the ASCOM Camera Chooser. There is no setup for the SSAG in BYE.

 

Now, assume that you have PHD running and guiding, you need to make sure that you have selected "Enable Server" on PHD's Tools menu. You should also have BYE up and running and connected to your camera.  You can go the BYE's settings screen, find the Dither settings in the lower left corner.  Make sure that PHD is selected as the provider and that the Host IP is set to "localhost:4300". Click on the Test button.  It should succeed.

 

If the above worked with no problems then you just need to click on the Dither button on BYE's main screen to enable dithering. It is beside Daylight toggle button in the upper right part of the main window. From then on dithering is automatic.  You should see the indication that dithering is occurring on the BYE progress screen between exposures and you should see a jump in PHDs output graph at the same time.

 

I hope this helps.

[jimwc6491]

Rick

Thanks

 

I assume that this is if I get the Guide camera running to PHD via ASCOM (I have never done that before always went direct to camera then BYEOS)

as soon as I get a Guide camera working VIA ASCOM Ill remember that. Ill get with Orion in the AM and see if they have any word on Win 10 Drivers.

[astroman133]

Jim,

 

Please read my previous note where I said "When using your SSAG with PHD for guiding, you would typically select Starshoot Autoguider as the camera, not the ASCOM Camera Chooser." 

 

When you choose Starshoot Autoguider as the camera type in PHD, ASCOM is not involved!!

 

I am not sure what you mean when you say that you "always went direct to the camera then BYEOS".  Which camera?  The DSLR is not involved in guiding and the SSAG is not involved with BYE! I am confused!

 

In any case, you may have a problem until Orion releases a Windows 10 driver for the SSAG.

[Ron Hillstromb]

  Jim

 

  I am running my SSAG on my Surface 3 Pro (Core I7), Win 10 (Upgrade version) with the V4 drivers.  I did have a problem getting it to load as I remember and opened a ticket with Orion Tech Support.  At the time there was an entry in the FAQ on the SSAG sales page that gave instructions on manually loading the drivers if they did not load automatically .  I went back and didn't find them as I remembered them but it was essentially start the driver loading software and when asked where to find the drivers to point the loader to the directory where the drivers were stored.  First I went to the x-64 folder but when I tried again I pointed to the driver folder where the x64 and x32 driver folders were located.  I have been using the SSAG with PHD 2.5 Dev 1.  The SSAG was put on the Surface around 1 September 2015 and I have been using it regularly ever since.  I went to the Orion Page to find the FAQ and saw that Orion has the statement that the SSAG does not work with Windows 10.  It does work on my Win 10 machine and as well as on my Win 8.1 and Win 7 machines.

 

  I just checked and the SSAG still works with PHD 2.5 Dev 1. 

 

  I doubt now that I will upgrade PHD until Orion does state they have a set of working drivers for Win 10.

 

  I have tried to copy and paste my problem description and effort to solve it but have not been successful.

 

Ron

[s3igell]

S3igell

 

I am aware that PHD doesn't need a driver, but the camera does. if there is no camera driver the camera wont work under windows. it might still work via ASCOM.

Orion is not keeping up with there windows drivers as well as the PHD revisions.  

I didn't say that the "SSAG doesn't need a Driver".  I said that "Orion had difficulty keeping up with 'Which Version of PHD2 is Most Current', and essentially Doesn't Try To" and that "PHD2 isn't affected by the Version Number that Orion posts to it's Website".

Honestly, Orion is rather bad about communicating most anything about their Devices (a common issue with many Astro Gear Companies).  You can usually find Better Info about Setup of the SSAG on either CloudyNights or AF.net or even the OpenPHD2 Google Group, than you can find on Orion's Forum.

As Ron (above) has described, most stories on these Forums indicate that the User needs to be rather Persistent and Technically Capable in order to get around Issues such as Orion's SSAG Driver Installation "Challenge".

 

I don't believe there is an ASCOM Driver for the SSAG, at least one that is not itself dependent upon a Native Driver being already Installed (same issue as PHD2).  If you find that I'm wrong, then please do make sure to post your findings here...

[Ron Hillstromb]

  I, hopefully, have attached a file which has how I reported the problem of SSAG drivers not installing on Win 10, the FAQ Entry that did allow the drivers to install with my note, and my response back to Orion Tech Support after successfully installing the drivers.

 

  This could be a problem that is hardware firmware in the computer dependent too.

 

  It does seem this topic has diverged from the original post.

 

Ron

SSAG Win 10 Driver Install.txt

[Dirty Harris]

We may indeed have wondered some from the original post, but let me just say gentlemen, it has made for some very interesting reading. Glad I'm not the only one to experience a bit of trouble with Orion's Tech Support. And as I've said before, this support/forum is a wealth of knowledge, appreciate the back and forth banter. Thanks again, Dirty Harris, Colo. USA.

[jimwc6491]

Ron

Thanks for the Info.

my computer is a Dell Insipiron 15 5000 series laptop with a Pentium processer 

 I will uninstall all the Orion SSAG drivers and try again. maybe something got scrambled in the process.

 

sometimes starting from scratch works.

 

I am getting a more than a little frustrated with Orion. I had some problems with my Win 8 computer also.

but got it working, then I lost a USB 3 and USB2 port leaving only 1 USB2  port.

That is why I am up grading to a new computer.

 

Ill let every one know my progress.

[Ron Hillstromb]

I am interested to see if more than one Win 10 computer will run the SSAG.  I decided to take a chance and installed the PHD 2.5.0Dev5 and it works with the SSAG.  This Surface Pro 3 had Win 8.1 on it and I upgraded it when I got it right after initializing and registering it.  So no leftover bits from programs on it before.

 

  After installing PHD 2.5.0Dev5 I got bolder and installed my Orion High Resolution Planetary Imager and Auto Guider (HRPIAG) ASCOM driver on the Win 10 machine and it installed and works too.  Now I have multi backups for autoguiding including the HRPIAG, ZWO120MM and a host of DSIs I own.  As a note the HRPIAG is no longer even on the Orion Website.

 

  While I don't know this to be a fact I believe Orion sells a lot of rebranded equipment.  At one time the SSAG used QHY drivers but then Orion made their own and it took forever to get drivers that worked with something other than XP machines.  Of course they aren't the only ones who do such things.

 

  I have observed several other things when I buy from Orion but in general if I have a question they come back with an answer though sometimes it isn't what I want to hear.

 

Ron

 

Ron

[jimwc6491]

All that responded to my query

 

Thank You ALL 

 

well I uninstalled everything per the Orion Installation of new windows 8/USB3 compatible Driver instructions.

it looks like I missed a step somewhere in the uninstall process.

 

I have the win 8 drivers installed and everything seems to be working properly.

the light on the back of the camera comes on, and PHD2 seems to connect to the camera (at least there is light on the screen when I start a capture)

 

I was afraid I would have to buy another camera.

 

I will upgrade to PHD2DEV1 thru 5 one at a time to get to the latest and greatest

 

Thanks again

 

And Dirty Harris sorry for hijacking your topic I thought everything was pretty much settled on the original subject.

[Ron Hillstromb]

  Good to hear you got it to install.  Still Orion is in the dark for some reason by stating it doesn't work with Win 10.

 

Ron