quick question on guiding

[Guest Si2504]

I have read through the guide on guiding, and it mentions using a 2x barlow to achieve focus. is this necessary on all guide camera's to achieve focus or are some camera's able to get focus being attached directly to the guide scope? My guide camera is a Opticstar PL-131m coolair and does come with a little barrel that screws onto the front of the camera, which then goes into the guidescope.

 

As i have not been able to use it yet due to the clouds, i haven't been able to test properly whether or not this is the case. The guidescope is a Versascope 10x60.

 

thanks

 

[Perkil8r]

You won't always need a barlow no. It depends if there is enough focus travel on the scope. If there is then you will be fine, if not either an extension tube can be used or a Barlow will help in a slightly different way. The only issue with using a barlow is that you increase the effective focal length of the guidescope which can be a hindrance.

[red dwalf]

i wouldn`t use a barlow, but as Mike says you might need an extension tube to be able to focus properly, if you guide camera doesnt have one, i would also surgest getting an ir filter, this makes the guide stars nice and tight, some colour cameras have them but most mono cameras do not.

[Perkil8r]

There is a train of thought that says a slightly off focus guide star is a good thing, it helps stop trying to chase the seeing and makes guiding a touch easier.

[red dwalf]

i just go for a longer exposure time, about 3 seconds.

[Guest Si2504]

Ok thanks, ill see what i come up with when i use it.