SkyWatcher EvoGuide 50ED + ASI174MM Mini

[astro172]

Hi there.

I wanted to try out Polar Alignment for the first time.
I'm normally guiding with OAG, so I decided to add my old guide scope just for polar alignment. but I'm not sure if FoV is enough

SkyWatcher EvoGuide 50ED is 242mm
and ASI174MM is 11.3x7.1mm @ pixel Size 5.86um

is that enough?

plus. I'm mounting my EvoGuide in the finder shoe on my Esprit 100ED, will that be a problem?


Thanks

[admin]

Hi,

I think the field-of-view will be perfectly fine with that combination since the 174 is quite a big sensor. It's easier to deal with the problem of the field-of-view being too wide (you can just use a smaller ROI) than trying to deal with the FOV being too small, but in this case I think it will just work.

The only thing to be cautious of when mounting your guide scope in the shoe like this is that the measurements can be thrown off if there is any flex between the mount and the guide scope as you rotate the RA axis. Make sure everything is tightened up properly and use cable ties or Velcro straps to restrain the cables so that the shifting weight of the cable doesn't pull the camera or telescope out of alignment. Note that the alignment between the guide scope and the mount doesn't need to be perfect – it just mustn't change as you rotate.

Hope this helps, Robin

[astro172]

Hi,

I think the field-of-view will be perfectly fine with that combination since the 174 is quite a big sensor. It's easier to deal with the problem of the field-of-view being too wide (you can just use a smaller ROI) than trying to deal with the FOV being too small, but in this case I think it will just work.

The only thing to be cautious of when mounting your guide scope in the shoe like this is that the measurements can be thrown off if there is any flex between the mount and the guide scope as you rotate the RA axis. Make sure everything is tightened up properly and use cable ties or Velcro straps to restrain the cables so that the shifting weight of the cable doesn't pull the camera or telescope out of alignment. Note that the alignment between the guide scope and the mount doesn't need to be perfect – it just mustn't change as you rotate.

Hope this helps, Robin

Thanks Robin, that was helpful.

I also have the ASI290MM Mini, will it be better than ASI174MM Mini? or that's too small?

for the shoe mount, not sure if it will stay put. I'll tight the cable as you suggested, Many thanks

[admin]

Hi,

both cameras should work - give them both a try and see which works out to be more robust/reliable.

cheers,

Robin