Thursday, October 19, 2017

Astrophography with a 1 1/4″ focuser

March 13, 2009 by  
Filed under Articles, How To's, Starting Out

If you are like me, you are amazed by all the wonderful photos people are getting with their telescopes. Yes it does take a while and is not easy, but there are things you can do to try it out. We’ll focus on the types of astrophotography you can do with a  telescope that has a 1 1/4 focuser.

The type of focuser you have determines the type astrophotography you can do with your telescope. Since my first telescope was the Celestron Omni XLT 150 (6″ reflector), I was not able to mount a DSLR camera to the stock focuser for two reasons: you need a 2″ focuser for the proper connections, and the camera will be too far away from the optical tube assembly (OTA) to reach focus.

So unless you are mechanically inclined, stay with the stock focuser. (Here’s how I replaced mine:

http://tinyurl.com/br852t

That does not mean you can’t do photography though. You have several options available with a 1 1/4″ focuser.

jupiter-eyepiece1)Eyepiece
You can simply get a point and shoot digital camera and hold it over the eyepiece. I got my first astro photo this way. You will need to use a wide field eyepiece and hold the camera steady. Orion makes a cool adapter that lets you attach your camera to an eyepiece. You just attach the adapter to the eyepiece, and then attach the camera to the adapter. Make sure to use a shutter timer if your camera has one. Use manual settings if you got them on your camera. You’ll also want a small and light camera here.

jupiter2) WebcamYou can attach a webcam to the eyepiece and take images of Mars, Jupiter, Saturn and Venus and the Moon. Webcams are great for planetary shots. You pretty much just take a movie of the object and “stack” the images. The end results can be quite amazing. This is one of the preferred methods for imaging the planets. To do this remove the lens from a webcam, attach an empty film canister to the body of the webcam, and insert this into the eyepiece holder on your telescope. Now you capture the image with some software and stack the images from the AVI movie you captured.

sagatarius-and-milky-way3) Piggyback
If your telescope has a tracking motor you can attach a DSLR to the telescope. Celestron’s Omni XLT 150 has a bolt on the tube ring that allows for this. With this technique you can get amazing wide field photos. But your success depends on a decent polar alignment, focus and how dark your skies are. One of my best photos so far was using this technique. It’s also one of the most forgiving techniques. You will always get good results if you aim towards the Milky Way.
Give these techniques a try. There’s a lot to learn with these techniques that will carry over to other types of astrophography like using the manual settings on your camera, using your camera in the dark, and getting a good polar alignment.

Once you have mastered these things, you will be ready for the next step. But beware it’s not easy and it’s very contagious.

Comments

5 Responses to “Astrophography with a 1 1/4″ focuser”
  1. rick sullivan says:

    Hi,

    I just got an Omni 150 like yours for myself for christmas. I have a seen your set up video and have been trying to get an idea of your set up and learn from your journey into AP. I’ve seen your how to on your focuser mod on cloudynights and just found your website..not stalking, just trying to learn from what you have accomplished. 🙂

    I have a t-ring and adaptor on order for my DSLR to attach to the Omni. Does this article say that I won’t be able to focus through the 1.25″ focuser? Is that why you changed to the 2″?

    Thanks,
    Rick

  2. fuadramsey says:

    Yes it will focus (from what I remember). I moved to a 2″ focuser to install a coma corrector. It corrects the edge distortions you will see in photographs with this fast scope. I was also concerned with no glass infront of my camera’s sensor. The new focuser can accommodate for this. I sent you an email with more info.

  3. Atul says:

    I saw your post where you changed the scope to 2inch. the pictures are amazing in there. I have a omni XL150 the same telescope which you have used in there. After changing the scope to the 2″ Zumnell will i have to change the current T-adapter as well that I have for the 1.25″ scope?

  4. theharvester says:

    You wouldn’t have to replace the T ring as the new focuser should come with a 1 1/4 to 2 inch adaptor.

  5. theharvester says:

    Yes, the focuser was changed because there was not enough inward travel to achieve focus with the stock 1.25″ focuser.

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