9x50 finderguider or st80 guidescope?

[Garethr]

Hopefully this explains my description

Gareth

http://stargazerslounge.com/uploads/monthly_02_2015/post-32109-0-08538800-1424449048.jpg

[Atreta]

Gareth 

thanks for the tip and the picture. i have a small dovetail lying around, i'll try your suggestion, it looks nice and should be cheaper than the finder rings

gonna pay a visit to the pluming store check for it.

[malc-c]

[Atreta]

what dovetail model is that one? mine is smaller and has less holes

[Garethr]

Frank,

I bought it at an astro exhibition last year. Useful but have to take the weight into account when trying too keep things light. I'm sure you could make something a bit lighter. Might have to think about this myself as the poor old eq5 really struggles

Gareth

[Garethr]

Thanks Malc-c. I think it was you who out me onto these in the first place

Gareth.

[malc-c]

Here's mine

Only difference since this was taken is I now use aftermarket long / lattitude bolts

[lonebod]

Fantastic thread guys. Got loads of information. Gonna look at the finder guider for my 100ED.

There were a few comments about not using a finder for guiding on longer focal length scopes such as SCTs? I've also got a Celestron 9.23" SCT. Would that be better with an ST80? If so I might need to ditch my AVX and get something more robust!!!

Sent from my SM-G925F using Tapatalk

[malc-c]

Fantastic thread guys. Got loads of information. Gonna look at the finder guider for my 100ED.

There were a few comments about not using a finder for guiding on longer focal length scopes such as SCTs? I've also got a Celestron 9.23" SCT. Would that be better with an ST80? If so I might need to ditch my AVX and get something more robust!!!

Sent from my SM-G925F using Tapatalk

I think there is a compromise between the focal length of the main scope and that of the guidescope.  For example if you take a trace in PHD from a short focal length scope like a finder, and then repeated the same with the main scope, the trace would be nowhere near as flat with the main scope than the one from the finder.  So I'm guessing that with a longer focal length, the guide impulses when using a short focal length guide scope wouldn't have much of an effect to keep nice round pin-pionted stars.

[lonebod]

So would an off axis guider be better for long focal length scopes? Would thus also be suitable for short focal length scopes?

Sent from my SM-G925F using Tapatalk

[malc-c]

I'm no expert, but as you would be imaging and guiding through the same scope then the results should be very good indeed.

[Tinker1947]

Finding a guide star may present you with a bit of hair pulling, shorter FL scope will i think present more stars than a longer FL........