Auto guiding the dark art and auto focusing

[Dave1964]

Hi Steve,

Thanks I put up a couple of images of the m45 last taken with the mask on. I figured you had you keep the mask on once you got focused or in my case nearly focused. I haven't used one before so I wasn't entirely convinced of what I was doing with it:).

Dave

[Aenima]

Hi Steve,

Thanks I put up a couple of images of the m45 last taken with the mask on. I figured you had you keep the mask on once you got focused or in my case nearly focused. I haven't used one before so I wasn't entirely convinced of what I was doing with it:).

Dave

Dave, 

You use the mask to get the star light looking like an X with a line that is exactly in the middle, then remove the mask to take an image - the mask just helps you get the right focus without having to rely on the stars being your only reference point.

Once you get that -X- shape, make sure the focuser stays there (rack n pinion focusers often lock using a thumb screw but this can shift the focus slightly so do a last check with mask on) then just remove the bahtinov and start imaging - knowing your in focus - or observing the object of interest.

hth

regards

Aenima

[PhotoGav]

Great thread - covers exactly my thoughts at the moment re. guiding with the restriction of being away from the house. Had been considering a standalone solution, so interesting, though mixed, feedback on Synguider. My question about laptops is this: how long does the battery last (about as long as a piece of string, probably, but I have to ask) and is it possible to power it from a 12v power tank?

As for Bahtinov masks - they are great, so do persevere Dave. Works best with a brighter star, so you may have to slew away from your target object to satisfy that requirement, then go back once focused up. I'm using a 60d too and zoom in 10x in live view (with exposure simulation disabled in the menus), move around to find the bright star and then alter focus to get the x-wing thingy with the line in the middle as Aenima says. Remove mask and hey presto, pin sharp.

Good luck and please put me on the list for a few hours of #4!

[Dave1964]

Hi guys,

Thanks that's great advice. I now know what I need to do .

Now having never taken a laptop out in the field before. I am now assuming that the battery life will rapidly go down to the outside temperature especially in sub zero temps. Do I also need to protect the laptop from dew and cold too?

Dave