Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Focussing HX916


Spoon

Recommended Posts

Hi

Focussing a CCD takes a bit of practice but it's fine once sorted. Various ways to do it but for me the best way I find is to focus on a distant object in the day time and then make a note of the focus position for later in the night. Focusing in the day helps as everything is nice and bright so exposure times are short and it's easy to see what's going on.

Once you know the rough focus position its easier to find the focus at night, set the camera exposure to somewhere between 1 and 5 seconds, enable the loop function on the software and then make slow changes until you get focus.

Hope this helps.

Sent from my iPad using Tapatalk

Link to comment
Share on other sites

Hi

Focussing a CCD takes a bit of practice but it's fine once sorted. Various ways to do it but for me the best way I find is to focus on a distant object in the day time and then make a note of the focus position for later in the night. Focusing in the day helps as everything is nice and bright so exposure times are short and it's easy to see what's going on.

Once you know the rough focus position its easier to find the focus at night, set the camera exposure to somewhere between 1 and 5 seconds, enable the loop function on the software and then make slow changes until you get focus.

Hope this helps.

Sent from my iPad using Tapatalk

Ok will try it later. Thanks [emoji106]

Link to comment
Share on other sites

Hi

Focussing a CCD takes a bit of practice but it's fine once sorted. Various ways to do it but for me the best way I find is to focus on a distant object in the day time and then make a note of the focus position for later in the night. Focusing in the day helps as everything is nice and bright so exposure times are short and it's easy to see what's going on.

Once you know the rough focus position its easier to find the focus at night, set the camera exposure to somewhere between 1 and 5 seconds, enable the loop function on the software and then make slow changes until you get focus.

Hope this helps.

Sent from my iPad using Tapatalk

Think something is wrong, this is 1/100th second pointing at a treepost-22414-143272500554_thumb.jpg

Link to comment
Share on other sites

I would not bother trying to set focus in the daytime you will get near but you will still have to refocus on a star anyway.

It just takes longer with a hx916 , 13 seconds to download an image.

You can speed it up by binning the exposure x2 for a faster download.

Start with an eyepiece to make sure your finder scoop is set up then attach the hx916 centre on a star with the finder and take an exposure adjust focus and repeat until you hit the sweet spot for focus. A focus mask will be a big help if you don't have defraction spikes to help.

The 13 second download time is not such a problem when added to the end of a 300 second exposure.

Link to comment
Share on other sites

Focus the telescope for a medium length eyepiece with some bright stars in the field

Take the eyepiece out and replace with the camera. The hx916 is 17mm from flange to ccd so you might want to estimate moving th focuser 17mm in.

Take a ful picture.

Get the exposure right so your adu max is about 20,000

Select full screen stretch.

If you are inside or outside focus you will get donuts. A large distance from focus is parts of very large donuts. Close to focus is small donuts.

With the camera binning x2 or x4 put it on repeated imaging and slowly move the camera to make the donuts smaller.

Once the donuts are small, stop repeated imaging, select an area around one of the donuts and make it the imaging region for rapid downloads on repeated imaging. REduce the binning if necessary.

Continue focussing until this is as small as it can be. Move through focus back and forth a few times to validate.

Measure the distance on your focuser for an easy return.

Job done.

The biggest issue is overcoming the initial situation where you can't see anything and then getting the camera to download in anything close to reasonable for focusing. .

HTH

Mike

Link to comment
Share on other sites

Way to long exposure for a daytime pic with a sensitive CCD camera, a DSLR will take at about 1/250th of a second in daytime.

Try a much shorter exposure, about 1/1000th

You will get there in the end

AB

I can't go down that far haha. In Pix_H9_usb it's limitted to 1/100th sec

Cam

Link to comment
Share on other sites

I can't go down that far haha. In Pix_H9_usb it's limitted to 1/100th sec

Cam

That's strange, but if you can't then that won't work, but as Stu_2011 says above, that is how to get it to work in daytime, maybe try different software?

Regards

AB

Link to comment
Share on other sites

You can do 1/1000th of a second , you just need to select thousandths in the exposure range.

Below is 1/1000th through my 80ed and hx916 using Pix_h9_USB ( house behind mine at around 20 meters)

post-730-0-25328100-1433075409_thumb.jpg

Link to comment
Share on other sites

You can do 1/1000th of a second , you just need to select thousandths in the exposure range.

Below is 1/1000th through my 80ed and hx916 using Pix_h9_USB ( house behind mine at around 20 meters)

That's strange, my interface doesn't look like that!

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.