Focus help needed for a beginner

[Spectral]

Hello Everyone!

I'm just getting started with astrophotography and could really do with some help or advice with focusing. I've now made 2 attempts at some shots of the moon but can't seem to get any focus at all. I using a SW ST80 with a QHY5 and a Canon 350D camera with a T ring & T adaptor.

I tried the Canon first with the ring and adapter but could not get the focus dialled in at all, a fuzzy blob was the best that I achieved, the following night I tried the QHY 5 with QGVideo so I could see what was happening live better but all I got was the same fuzzy blob with zero definition of anything.

I'm using a prime focus setup and have tried combinations using the diagonal and without but to no avail.

What am I missing here and do I need any extra kit to make this work properly?

Any help would be greatly appreciated.

Thanks in advance!

[rfdesigner]

First you should achieve focus in daytime on a terrestial object at as long a distance as possible. You can then see what you're doing and it's a darn sight warmer.

Many scopes have their image plane set up for eyepieces, not cameras, which means the image plane is too far inside the scope... on the SW ST80 I would not use the 45 degree errect image, that's adding length which you will not want for imaging. (an eyepiece works by placing lenses beyond the image plane, a camera sensor must be on the image plane, so cameras are closer to the scope than eyepieces)

After that remember with the moon you are effectively imaging a desert in full daylight, so you need a REALLY fast shutter, something like 1/500th sec at ISO100 on an F5.... ish.

Derek

[Atlas]

Try using an extension or placing a barlow on the end of your camera, that should push the focal plane out so you can achieve focus.

[cantharis]

Try using an extension or placing a barlow on the end of your camera, that should push the focal plane out so you can achieve focus.

Useful to know about the Barlow.

[Spectral]

I ended up removing the lens from the barlow and using it, this has improved the QHY5 focus a lot. Thanks Atlas.

[Wobbly Bob]

Extention tubes are the way to go as you found out with the barlow minus lens.

[Herbig]

When you get on to DSO's etc you will need a Bahtinov mask

[Atlas]

I ended up removing the lens from the barlow and using it, this has improved the QHY5 focus a lot. Thanks Atlas.

Np, glad I could help.