First images, questions about DSLR attachment

[jahnpahwa (JP)]

Hello team,

My fourth night with my set up last night, and I got some pics to show for it. My set up is getting better, but there is still plenty of work to do.

So, I've tried attaching my barlow (GSO 2" ED) to get in closer, but cannot achieve focus. Can anyone let me know the order of attachment to shoot with a barlow? I was trying barlow into OTA, then barlow into 2" adapter to t-ring to dlsr.

I've also tried the camera on the baader hyperion EP, just screwing the camera onto the EP in the same configuration that I use for visual doesn't work. I've since read that i need 32mm or so spacing between the camera and EP... can anyone give advice on the sequence of gear from camera to OTA here?

Thank you!
JP

[Harpage (Danh)]

Hi JP,

You're using an 8" newtonian - correct? Since the ones bundled with the HEQ5 are designed for imaging, you will most likely reach prime focus, so you won't need to use a Barlow Lens. A Barlow Lens slows down your imaging time as well (e.g. f/10 is 4x slower than f/5 - you can compare the squares). At the moment you just need a T-Ring and T-Adapter, and later on you'll probably want to get a coma corrector and autoguiding.

[jahnpahwa (JP)]

Originally Posted by Harpage

Hi JP,

You're using an 8" newtonian - correct? Since the ones bundled with the HEQ5 are designed for imaging, you will most likely reach prime focus, so you won't need to use a Barlow Lens. A Barlow Lens slows down your imaging time as well (e.g. f/10 is 4x slower than f/5 - you can compare the squares). At the moment you just need a T-Ring and T-Adapter, and later on you'll probably want to get a coma corrector and autoguiding.

Yes, thats it, I was able to get prime focus with just the t ring and adapter, but i wanted to use the barlow as a zoom of sorts... is that not possible? Same with using the eyepiece for projection, I want to get in closer or at least have a say in framing an image. Perhaps this is just done with cropping later on?

[jahnpahwa (JP)]

Here are a couple of pics i took. I think the green one is tarantula and when i saw this i thought i'd like to get in closer

[Harpage (Danh)]

You could use a barlow to zoom but like I said before, they drastically slow down your imaging time meaning you need longer exposures to make up for it (which makes your images more prone to polar alignment and tracking errors). Regarding your Tarantula Nebula image - you just need more exposure time. You can clearly see the outer and faint regions, which just need more light in order to reveal that detail.

[jahnpahwa (JP)]

Originally Posted by Harpage

You could use a barlow to zoom but like I said before, they drastically slow down your imaging time meaning you need longer exposures to make up for it (which makes your images more prone to polar alignment and tracking errors). Regarding your Tarantula Nebula image - you just need more exposure time. You can clearly see the outer and faint regions, which just need more light in order to reveal that detail.

unreal, thanks Danh

[Mickoid (Michael)]

JP, you shouldn't require the T Adapter for prime focus, just the T Ring to connect your camera to the telescope focuser. Once you start introducing more optics such as the Barlow lens into your optical train, you dramatically reduce the amount of light reaching your camera sensor. As mentioned above, with a 2X Barlow for example, you will change the focal ratio on a f5 Newtonian, to f 10. Depending on the quality of the Barlow and guiding, you may also dramatically reduce image sharpness due to lens aberrations and increased magnification.

With the Barlow connected, you will have to place it at the right distance from the camera sensor to achieve focus. By moving it forward or closer to the camera in the T Adapter, you will have to find the right position, trial and error, as they say! If you want to zoom in, either crop your image in post processing or buy a telescope with a longer focal length.