Guide Camera

[Thinker3932]

So i am confused.  I bought a guide camera and scope.  I mean, if I want to do both guiding and dithering, am I able to make all this work with BackyardNikon?  I am confused by some people who say I don't need a guide camera as BYN provides that through the camera itself.

[astroman133]

If you use a program like PHD2 to manage autoguiding, it can also do dithering.

Autoguiding makes frequent (say every 4 or 5 seconds) microadjustments to the mount to maintain the position of the guide star at the same position in the guide camera. This occurs while you are imaging through the main scope with your Nikon camera and BYN.

Dithering is typically larger adjustments that have to happen between capturing of images with BYN. This requires BYN and PHD2 to communicate with  each other. The settings screen in BYN allows you to configure BYN to communicate with PHD to initiate dithering.

When BYN finishes capturing an image it sends a message to PHD2 that it is OK to dither now. This causes PHD2 to stop autoguiding and perform dithering. When dithering is complete PHD2 resumes autoguiding. BYN knows when PHD2 has completed the dithering step and has resumed guiding and  starts the next exposure.

One thing that may be confusing is that BYN can be configured to dither on its own, without using PHD2. However, if you are using PHD2 for autoguiding you should also configure PHD2 as your dither provider. It only makes sense to use BYN's ASCOM dithering feature when you are not autoguiding.

There are a couple of older articles in the How To forum that may be of interest:

and

Keep in mind that these articles are 8 years old and so BYN may have changed since they were posted. Most of the information should still be useful for you.

I hope this is useful.

[s3igell]

8 hours ago, astroman133 said:

One thing that may be confusing is that BYN can be configured to dither on its own, without using PHD. However, if you are using PHD for autoguiding you should also configure PHD as your dither provider. It only makes sense to use BYN's ASCOM dithering feature when you are not autoguiding.

Only thing to add/emphasize: 

If you are running PHD (it's now PHD2 - OpenPHDGuiding.org), you really MUST use the interface between your Image Capture Software (BYN) and your Guiding Software (PHD2).  Otherwise, PHD2 would actively fight the Dither Motions which BYN would issue to ASCOM.  At best, you'd end up with a smear of motion captured at the start of the next BYN exposure.  At worst, you'd end up with PHD2 stopping guiding due to Lost Guide Star errors (and then motion blur as you are no longer AutoGuiding).

[admin]

On 9/10/2022 at 10:16 PM, Thinker3932 said:

So i am confused.  I bought a guide camera and scope.  I mean, if I want to do both guiding and dithering, am I able to make all this work with BackyardNikon?  I am confused by some people who say I don't need a guide camera as BYN provides that through the camera itself.

Your Nikon DSLR is meant for imaging only, it cannot guide. You were ill-informed.

Your guide camera, as the name implies, is meant for guiding, via PHD.

In summary

• BYN does all the imaging with your Nikon DSLR
• PHD does all the guiding  and does all the dithering with your guide camera
• BYN sends all the commands to PHD to dither, and pauses the imaging session until dithering is complete (it's all seamless)

Hope this helps