A tip on how to Focus when taking astrophotos on an ETX

Post by **Airconvent** » Thu Nov 06, 2003 1:26 am

Hi,
Someone posted his idea to me about how to solve the focussing problem when using a digital camera with small LCD screen.

--- Jay Ward <jaywward@gate.net> wrote: -----
I read your comments about out of focus shots w/your Nikon. Here's howI solved that problem.
During daylight, focus on something earthbound that is brightly lit andeasy to focus on. Now remove the camera and place the EP minus thecamera back in the scope, adjusting the seating depth till the image isin focus to your eye. For my setup the difference was about 1/8 of aninch.

I machined a ring from PVC that matched this amount. I slide it ontothe EP for focusing, then remove it, install the camera, reinsert it inthe scope, and everything is in sharp focus.

If you don't have a lathe, make a spacer from sheets of paper. You canalso add a parafocal ring to another eyepiece with it set to focus atthe same point. Swap EP's and your good to go.

Visit my website http://www.gate.net/~jaywward to see some examples ofmy pics.
Click on the previous pics link to see several of my lunar and astroshots.

It sure made taking pics with my CP5700 a lot easier.

Jay

Post by **weixing** » Thu Nov 06, 2003 1:58 am

Hi,
I have taken some images and also have this problems. The saturn and Mars are too small to focus properly even with the extern LCD monitor I have didn't help much, because the resolution and contrast of the LCD are not good....

The solution above may have some problems - The focusing knob of the scope are quite sensitivity and may have accidently shift without your knownledge, unless you wait at the site till night...

Anyway, my solution now is to focus on the Moon or a bright star (hey... Sirius is up...

) first, before I point to my target... I will try this method next time when the sky is clear...

Post by **Airconvent** » Thu Nov 06, 2003 2:10 am

weixing wrote:Hi,
I have taken some images and also have this problems. The saturn and Mars are too small to focus properly even with the extern LCD monitor I have didn't help much, because the resolution and contrast of the LCD are not good....

The solution above may have some problems - The focusing knob of the scope are quite sensitivity and may have accidently shift without your knownledge, unless you wait at the site till night...

Anyway, my solution now is to focus on the Moon or a bright star (hey... Sirius is up... ) first, before I point to my target... I will try this method next time when the sky is clear...

hi weixing,
actually you did not understand the true essence of his solution.
what you need to do is align your eyepiece to the camera. Once this is done, you only need to focus using your eyepiece, then change to the camera WITHOUT touching the focus knob and you can take sharper images. Of course, there are other problems such as narrow FOV of the scopetronixs digi-T may mean the image may not be in the FOV when you put the camera in but I guess once can experiment for the best combination...cheers

rich

Post by **weixing** » Thu Nov 06, 2003 10:23 am

Hi,
Ooh..... Sorry, his mail is too brief on the focusing part... Anyway, That a simple and interesting idea.....

Today weather seem to be quite good, I will try it out tonight if sky is clear....