Orion 50mm Guide Scope + QHY5 focus

[evilloz]

Hi All

Just got myself an Orion Deluxe Mini 50mm Guide Scope with Helical Focuser (http://www.telescope.com/Telescopes/...0/p/102417.uts)to use with a QHY5

I can't seem to get it to focus

Has anyone got a similar setup? Are extension tubes required to get this guide scope to focus?

[Moonman (Michael)]

Try focussing visually with an EP that is par focal.

An extension tube may push the camera too far back from the focus point.

You can screw the front objective out to slightly increase the focal length too and achieve focus that way. If this is necessary you may need to secure it with black tape if it is hanging on the last few rims of thread.

Hope this helps

[naskies (Dave)]

Yes, I have an Orion 50 mm guide scope and QHY5 (but without the helical focuser). If you're more than a couple of mm away from being in focus, the whole image will probably be black.

One way to get started is to point the guide scope at a really bright star like Sirius or Rigil Kent - just line it up roughly by looking through the scope (don't need an eyepiece).

Fit the QHY5 (I'm guessing the focus point will be somewhere close to racked in all the way), then take a really long exposure such as 10 secs. You should see a blurred outline of the star. Adjust the focus by a couple of mm in either direction. Take the 10 sec exposure again, and see if it's closer/further out of focus.

As you get nearer to the focus point, the star will become brighter and so you can reduce the exposure. Keep tweaking until you're spot on. At this point, I usually like to get a pencil and draw lightly on the tube to mark where the focus point roughly is for next time.

Hope this helps!

[evilloz]

Thanks Michael

Thanks Dave

I'll try it again tonight and see if it works

[Astro_Bot]

I use a QHY5/Finder-guider but have an adapter from Modern Astronomy:

http://www.modernastronomy.com/accessories.html

Using the adapter puts the camera focal plane well within the normal focus adjustment range of the finder.

The main benefit is that, once adjusted and locked down, the focus should never have to be touched again.