3 replies to this topic

[AstroLens-188]

Hi everyone!

 

I am new to Cloudy Nights and I would like to post a topic about something that's bothering me:

 

I have a Celestron Nexstar 130SLT that I wanna use for imaging.

I've got everything else I need for astrophotography (i.e. camera).

 

However, I have a slight problem..

My camera cannot reach focus with the telescope at all.

 

And after doing a lot of research, I apparently must modify the primary mirror.

The modification process involves moving the mirror forward with a set of bolts and other stuff.

It's easy to do and you don't need a lot of items.

 

But the problem is that I want to use my telescope for visual astronomy and imaging astronomy.

So when you modify the mirror, you can no longer use the telescope for visual observations.

 

I did find another way of achieving prime focus without modification.

All that needs to be done is simply adding a Barlow lens on the camera (With a T ring adaptor of course).

And this works fine.

 

However, when using my Barlow lens in combination with my DSLR camera, it makes my telescope more zoomed in.

This can severely cut off my field of view (FOV).

 

I captured a photo of the Orion Nebula and I couldn't get the entire nebula in frame.

 

 

Is there any other way I can try to get prime focus without using a Barlow lens or modifying the mirror?

 

By the way, my camera is the Canon EOS 450D

 

If you know anything, please let me know! I would HIGHLY appreciate it.

 

 

Thanks.

Edited by AstroLens-188, 22 April 2025 - 04:19 AM.

[sevenofnine]

Welcome to C/N! 

 

It's a common problem with those just starting this hobby. They think of all aspects of it as one and want one scope that conveniently does it all. Unfortunately, it just doesn't work that way. Thinking of each requiring different equipment is more like it. Choosing what's best for you and your budget is another matter. Another way to look at it is to choose which aspect of astronomy interests you the most right now and just buy equipment for that hobby and save adding additional equipment for a latter date. For instance, I just solved the imaging bug which is expensive and labor intensive by buying a new smart telescope. I suggest the forum recommended astrophotography guide book before proceeding with equipment. Good luck! 

 

https://www.amazon.c...,aps,365&sr=8-1.

 

.

Edited by sevenofnine, 22 April 2025 - 09:20 AM.

[AstroLens-188]

Hello sevenofnine.

 

Thank you very much for your reply!

 

I guess what you said is true.

 

I'll probably just modify my telescope instead of visual use and use it instead for imaging.

 

 

Thanks for the info.

 

 

- Astro Lens

 

 

 

P.S.

 

I have a YouTube channel if you wanna check it out.

Here is the link:

 

https://www.youtube.com/@astrolens-188

Edited by AstroLens-188, 23 April 2025 - 12:23 AM.

[Jon Isaacs]

But the problem is that I want to use my telescope for visual astronomy and imaging astronomy.

So when you modify the mirror, you can no longer use the telescope for visual observations.

 

 

You can use the telescope for visual observations, you just need an extension tube in the focuser.  When you move the mirror, you move the focal plane further from the secondary and an eyepiece may not come to focus with the focuser racked all the way out.  An extension tube that matches the distance you moved the mirror should take care of that.

 

Jon