Canon 300d focussing issues

[Sfarndell]

I have a canon 300d, but am getting frustrated by trying to focus it. My current setup is the canon mounted afocally on an LX200 10" classic with superwedge. Still not clued up enough to do autoguiding, but have the setup for when I improve.

The repeat process of taking an exposure (usually 5-10 sec), then pressing the review button, manually zooming in to check focus, then repeating until focus is "relatively sharp" is tedious. With the screen being nowhere near the capable resolution of the ccd I can't get sharp focus, despite the use of a hartmann mask. Next best would be to use a usb interface to download the image immediately and then zoom in with software.

However, I am hoping that someone has a shorter cut to this (e.g. is there a way to "live view" the image on the screen/laptop?).

[Milamber]

You could do what I did at Kelling... point at Jupiter (or some bright star) and focus on it - simply because if you can see it in the viewfinder it will be pretty close to focus, if you can't see it then it isn't. Worked reasonably well too, gets you to within a gnat's whisker anyway...

http://stargazerslounge.com/index.php/topic,32443.0.html

Arthur

PS - *hoooge* compression in those pics, nowhere near as bad as they look posted!

[beamer3.6m]

I have marked my focuser tube (works on a newtonian anyway) with a pen at the point where the 400d is in focus.

When I want to focus I just move the focuser until I reach the pen mark and voila, your in focus.

It may a little nudge to get bang on but it saves so much time and is cheap, easy to do and once marked it takes no time all to achieve focus.

[steppenwolf]

This page on my website will reveal the tried and tested method I use!

Click on the text above!

[George]

This page on my website will reveal the tried and tested method I use!

Click on the text above!

I use DSLR Remote Pro too, I also use it to detemine best ISO for the session on current seeing/LP conditions as the images taken are instantly displayed.

It will do upto 30 sec exposures.

http://www.breezesys.com/DSLRRemotePro/index.htm

[trevboyd]

Get yourself one of these:

http://stargazerslounge.com/index.php/topic,30884.0.html

I made one out of card. I find that I can't see the diffraction spikes in the viewfinder (although I can in an eyepiece), but I take a quick exposure, check the resulting image on the screen, adjust and repeat as necessary. The mask makes it very very obvious when you're in focus, and if your last adjustment was in the right direction.

Trev

[Sfarndell]

Thanks guys for all the help!

All suggestions are great. My camera not advanced enough to warrant DSLR Remote pro, but DSLR Focus should do it for me. Until i can organise a serial cable connection, I'll give that wicked-looking harmann mask a try.

[Sfarndell]

As a follow up, I made the Bhatinov mask and it works a treat. Tried it last night for the first time (just optically) and it is "the business". Realised I had to collimate my scope slightly too :mrgreen: . Really easy to determine how far focus is off, and which direction to correct for it.

Can't wait to get imaging.

Thanks guys for the info!

[Psychobilly]

Glad People are putting the masks to good use

Anymore for Anymore....

Billy...

[blinky]

The mask is the 2nd best thing I have made for my scope (The Pier is the best!). Works amazingly well

[iancandler]

I use one of the optical right angle finders you can find on e bay, it has a built in zoom which is handy.. I then focus on the brightest star in the part of the sky I want to image and go from there.

[vincentnm]

I use this with my Canon 350D. It gives me a razor sharp focus and the procedure hardly takes a few seonds.

http://www.kwtelescope.com/KWT_FotoSharp.htm

The only limitation is that I need a mag2 or brighter star to focus on. I can usually find this not too far from my target, focus, and slew back to the target without crossing the meridian (to avoid mirror flop).

Regards,

Vincent Morris.

[Reggie]

I'm still using liveview on the back of the 450d and the WO 66 has a cm/mm scale on the focus drawtube

[Jarvo]

I have to find a star bright enough to view in the preview screen of my Olympus, focus then line up the target. Not an exact science but I get by for now.

Jarvo