Jump to content


Recommended Posts

Hello to all,

My equipment so far

Explore Scientific ED80

Skywatcher  EQM-35 

Canon EOS Rebel T8i

Orion 50MM Magnificent Mini Guide Scope and Camera

Here is my question:

Went out for the first time the other night and was going to just practice on the Moon. Well I could not get any focus even using both extension tubes included with scope.

Had someone tell me to use the diagonal and I did get focus with it using no extension tubes at all but is the the proper way and will I be able to shoot Deep Sky ?

Am I missing something on the setup ?

Any guidance would be greatly appreciated.


Link to post
Share on other sites

Seems strange, i am def no expert, so i can only ask if you've tried (which i assume you have but been taught never to assume) no extension, one extension, two extensions ? what size are the extensions youre adding ? I needed just a single 20mm extender on my WO Z61.

Link to post
Share on other sites

Perhaps speak to the retailer, just reading another post on cloudy nights with same issue and he was using two spacers and a Field Flattener and was still struggling, it was with a pentax but it does suggest the ES ED80  needs a hell of a long train back to the camera sensor.

Link to post
Share on other sites

Thanks for the info. I contacted retailer and they asked me to try the diagonal and I did and that is how I actually got it to focus but this just doesn't seem like the best way to be setup for deep sky.

I used the diagonal with no extension tube and got it to focus.

I have read it loses some light input which to me sounds like the quality would drop off as well.

I have ordered another set of extension tubes to try. I will update after I get them and try it out.

I am total beginner in this and just want to do it the right way and not be fighting Myself doing it all wrong and get discouraged with it.

Link to post
Share on other sites

Updated my profile pic with the shot of the moon that I got with the diagonal. played with ISO a bit to get the reflection in the clouds. 

was a cloudy night but was trying to get the focus to work and hoping for a nice evening this weekend to try more.

Sorry forgot I can put the pic here so it can be seen better. Still learning this forum stuff as well..lol 

No processing this was just out of the camera as well. Retailer just wanted a shot plus nothing was tight and I hit the shutter no remote

I was just super excited to see something in my camera. :) 775173936_Moon2.thumb.JPG.7c488b40cac2e7dbfe43e816a42528d3.JPG

Link to post
Share on other sites

If you measure from the lens elements 480mm down the tube to the sensor mark on the camera it should give you an idea of where infinity focus is. You shouldn't need to use a diagonal as you'll be limited by the quality and condition of the mirror. Try to focus on a distant tree or landmark during the day to get you somewhere near.

Link to post
Share on other sites

Are you using a flattener or flattener reducer?

If not then you may need additional extentions to account for the lack of flattener in the imaging train.


  • Like 1
Link to post
Share on other sites

Thanks for the video link.

I will have to learn the measuring thing for sure. First time I have heard of how to do so..so thanks for that info.

Adam - I do not have a flattener or flattener reducer...I understand the flattener purpose but what would the flattener reducer be for?

Thanks to all for all the help and guidance.


Link to post
Share on other sites

The reducer changes the effective focal length of the telescope so in a 500mm scope a 0.8 reducer changes this to an effective 400mm.

The main reason to do this is to allow a camera to see a wider field of view than it would without the reducer.

As this is a photographic function it is common for a reducer to also have a field flattener combined with it.


For visual use you would use a longer eyepiece ie 25mm to view a wider field

(compared to eg a 10mm eyepiece)

Link to post
Share on other sites

Hey Fifeskies

Ok so that all makes sense...thanks for the info for sure.

So I bought more extension tubes and have now got a live view working BUT...it only shows in AV mode or fully automatic..when I switch to M mode the screen just goes to a white/gray color 

This a setting in my camera that I am missing? And yes I am completely new to any kind of manual mode on DSLR


Thanks again to everyone,


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • 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.