Guider calibration and camera questions

I captured some Ha on M82 last night. The subframes look great!

I did have a few issues with last night’s session, however.

First, I kept encountering Voyager’s insistence that the autoguider be calibrated when it should not be necessary. The scenario:

  1. The session started uneventfully via a DragScript I use for a single target. PHD2 calibrated perfectly. The camera started capturing Ha light frames.
  2. I realized I had not set camera’s gain correctly for narrowband!
  3. I paused the sequence and tried to change the camera setting. Unfortunately, the camera’s gain cannot be changed with the camera connected. (Leo, can this behavior be modified to allow camera setting adjustment while the camera is connected, please?)
  4. I aborted the sequence, disconnected all of the equipment, and changed my camera gain (I can’t wait for individual connect/disconnect buttons–I’m glad you are working on this, Leo!).
  5. I reconnected the equipment and tried running a modified version of the DragScript that did not include guider calibration (because I just calibrated it!) but the DragScript failed because Voyager thought the guider was not calibrated. The Goodnight action ran, resulting in the mount parking and the camera warming up. :cry:
  6. Wiping away my tears, I ran my original DragScript with calibration. The calibration was not as good as the first but everything worked until the morning.
  7. Total time lost: about 45 minutes.

Here is a screen shot showing proof of a calibrated auto guider in the status section and a simultaneous error about lack of guider calibration in the Monitor. Confusing.

Leo, can you please please please remove the requirement for autoguider calibration? I admit that I stopped the original DragScript due to an error on my part, but recovering from that error was much harder than it should have been. In this case, I had a perfectly good calibration, but just because I had to disconnect and reconnect my equipment, the calibration was not recognized by Voyager. PHD2 will hold a calibration across multiple sessions, and if nothing has physically changed with the equipment, there is no need to redo a perfectly good calibration. Would you please consider removing the requirement for calibration with every run?



Dear Glenn,

Voyager working doing calibration each time for each target and also when changing meridian. Voyager is a system integrator … not all system have memory of calibration or can revert vector in meridian flip or simple completly wrong reverting vector … this mean you lost so many time and switch from another program to Voyager after some months of tribulations.

That say, if you want to work with PHD2 that manage for you the guiding … is not true that vector is the same for each target … just in the real word. You can tell me it work … is a different thing, again so many user coming to Voyager after using program that hold calibration because they have problem with guide and calibration.

SGP have done a lot of damage in people mind and in a way they work … calibration is needed and doing astrophotography is not a race against time …must be an hobby and relax … better to have good data than have problems. This is the Voyager phylosophy … i can help you all to match your request but not at price to make Voyager not stable for all.

Doesn’t exists a good or bad calibration … exists a calibration with some DEC with some temperature with some humidity whit some cable arrangement with some balancing in some place … like doesn’t exists a pefect point were to calibrate !

GAIN and CMOS … ASCOM doesn’t have access to gain and offset and i cant manage… I dont add access to direct API of cameras because is not in my intentions. If there’s a camera ASCOM driver i prefer to use it.

Again if you think to work with voyager like work SGP is a way to hate Voyager.

Say all of this i can do something to help you and is remove check for calibration not done in Voyager but only if Voyager is not closed. Voyager need that calibration is done with is interface and not to read from exernal program … this for safety because it dont trust anything from external program for choice. You can say is not good , is so bad , is so stupid but …

If i do all the thing that doing the others famous Automation program i go in the same mistake. This is not my way.

If you fond this not good for you all i’m happy to refound money … no problem.
Please remember that when you use this program you are using also an experience from one AP with high skill …

All the best

Hey Glenn,
I’ll let Leo chiime in here but a couple of things you might check if you don’t want to calibrate every run:

  1. Instead of hitting the green arrow to start your sequence, hit the double blue arrow. You can then choose the startup options.

You can do the same thing from your DragScript screen by right clicking on a Sequence action in the DragScript tab (not the editor) and selecting Sequence Startup Override:

Also, if the Calibrate Guide checkbox is unchecked, Voyager will not run the Calibration:



I never recalibrate my guider - haven’t for several years. I keep the guide camera in the same orientation to the guidescope. I set things up so Voyager never recalibrates. It works very well. PHD2 is just measuring the angle and speed of guide corrections and these can be setup to be constants. Unless something is seriously broken with your mount if you recalibrate you will just get the same answer back!

To me recalibrating is usually unnecessary and it is just something that will potentially fail during an overnight run so it is actually less robust to recalibrate constantly. Back when I used Maxim DL for guiding it was a nightmare at times to have it consistently recalibrate. PHD2 is much better behaved but still unless you are using a rotator I don’t think reclibrating should be a requirement. Users need some wiggle room to do things as they see fit.

Since clearly people have different methodologies handling this and both camps have been successful over time it good you can have it one way or the other.

Sorry Mike … is not for now for to many reasons … if you want to use in this way you can … just dont use calibration flag in sequence and do a calibration at begin of night. Dragscript can help you to realize that. I have different vision and contacts with a lot of user having problems exactly from the way you use.

Leo, after reading your other post about the features that Voyager lacks, I can’t help but feel I might have offended you with this post. If so, I am sorry—that was not my intent.

Like others here, I am trying to make my astroimaging workflow as efficient and reliable as possible. I realize that sometimes this requires changing software or gear, and sometimes it necessitates changing the way I work. The developers of PHD2 recommend calibrating near the meridian and celestial equator, and not to recalibrate again if the equipment has not physically changed, but if you tell me that your approach is better, I will try it. I certainly have a lot of respect for your accomplishments both as a programmer and an astrophotographer.

Voyager is a wonderful program. I have used the alternatives you mentioned and have chosen Voyager. I appreciate your vision for the program but do hope you will consider developing features that many of us would find useful.

Kind regards,


Im not offended, just want to be clear how Voyager work, what can do and what cannot do.

All the best

I fixed this how you requested, see new Daily Build versions. Let me know if this work for you:

All the best

Thanks so much, Leo. I realize this change is something you are philosophically opposed to and it was gracious of you to change it.

Funny thing is, I tried checking the calibration button in the sequence I ran last night to allow PHD to calibrate on target and it went very well! I will continue to test out your method. I’m trying to keep an open mind about this and so far, I’m pleasantly surprised.

Thanks again.


Rowland, I appreciate your response and have been meaning to get back to you about it. I will try the sequence startup override function. Thanks for your help.

Kind regards,



I’ve been experimenting Voyager for the last2 or 3 days.

Question about guiding:
What’s the difference between Voyager RoboGuide and Native Guide Cntrol?
Out of my experience, the latter is just whatever software I am using for guiding (PHD2 on my setup).
Is the first one for OAG setups?

Me personally, I can’t get to calibrate guiding, no matter which of the two I choose. Any clues why?

And last is, what are the advantages, from the developer POV, to calibrate every single session, especially through Voyager?

Thank you

Roboguide found itself the guide star in your guider image instead of the extyernal application and apply some constraints. OAG or not nothing change in guide to setup.

To calibrate you must choose in Sequence to do calibration with flag, more info here:

Not all setup can manage a one calibration and forget , especially long focal or high res … place where to shot, night temperature and humidty, balancing, mount gear coupling and so will be better managed if you recalibrate…also Voyager calibrate in the sequence when you change the meridian side.

You can avoid this and use external program features and not calibrate in Voyager, like PHD2 can do.
You are free to choose.

All the best

Leo, thanks for the clarification, now makes more sense.

Nevertheless, from my side, I can’t make it work. I check all the flags (calibrate guide and guiding) and I get an error -->

Calibration Guide Error (Calibration Start Failed (Error during PHD2 StartCalibration [RoboGuide][SaveImage] Command Request : [NON_ESEGUITO] no image available))

But if I choose Native Guide Control, it works without any issue.


PHD2 send back to you a “No image available” at request of SaveImage remote command, nothing to do with RoboGuide or Voyager. Please anaylize log of PHD and ask support about in their system.

All the best

For future reference of the users in this forum, I solved the error described above by permanently disabling Win10 antivirus. My PC is only to be used in this hobby, so be aware about how you do it. You can still disable it temporarily, adjust in accordance with your needs.


Miguel you cannot recommend to remove the Antivirus protection, just do what I have reported many times in forum, add PHD2 and Voyager to the exceptions of antivirus and antimalaware.


I wrote that people should act in accordance with their needs. To me, creating an exception for PHD2 and Voyager didn’t work at all, I actually had to turn antivirus off. Maybe creating an exception is enought for the majority of the users, and I agree that they should try that first. To me, just because I only use that computer out of a network, I could afford disabling the antivirus.


Problem usually is Windows Defender, there are 3 kind of exceptions: file, process and folder. You must activate all the 3 kind of exceptions.


Sorry for bringing this old topic back but I would appreciate if some of you could share their 5 cents about the following : I do calibrate before each session directly via DragScript (somewhere in the intersection between the celestial equator and the meridian). Just one calibration - regardless of the number of targets.

Out of curiosity, what would be the rationale(s) not to use the aforementioned approach but rather just tick the “calibrate guide in sequence” ? As I understand, this latter will calibrate juste before the sequence and near your target.

I am aware there are quite strong recommendations out there to calibrate near the equator, etc, but I think Voyager made this feature available for a good reason.

Thank you for your feedbacks and excellent summer break to all of you,

The reason is that it must be calibrated to the dec of your target and in general close to the target. This has been the case since the dawn of time and has always been done like this until to become smart and no longer calibrate the calibration vectors can be modified by an equation which as such is due to its fallibility under certain conditions and polar alignment differences. brings problems, especially to the meridian if you use a model. Then everyone now does as he wants and most of those who photograph today have no previous experience to know certain things because obviously they have not lived them. I, who am a living dinosaur, have decided that certain things must be in my automation program. The post is old now you can calibrate, not calibrate, calibrate once, calibrate by target before and after the meridian. Everything is fine as long as it works, when you no longer work some questions (in addition to checking the trivial) you should ask yourself but I fear that this is not a public forum is of little use in this regard.

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