New to Astrophotography

[Northwoods Bill]

I am trying to get into the world of Astrophotography and I have a few questions. If a few folks here could jump in I would really appreciate it.

I will be using an Orion 8" Reflector with EQ Mount and auto guider (on loan from a friend) and a Canon T2i. I have read a bunch of items back and forth between mounting the camera to the viewpiece of the scope with an adapter ring or using the camera piggyback onto the scope. Can someone help me to understand the difference and why one would be desirable over the other?

Thanks!

[cyberon]

Focal Length!

[Northwoods Bill]

Are you asking the focal length of the telescope? If so it is 1000mm

[dougj7]

what lens would you be using if you mounted the camera piggyback on the scope? mounting the camera to the telescope will give you a narrower field of view than most camera lenses.

[Northwoods Bill]

Right now choice of three that I own:

Canon EF 70-200 F4 L
Canon EF 135 F2 L Prime
Canon EF 100 F2.8 L Macro

Open to other suggestions

[the jimmy]

Originally Posted by Northwoods Bill

Right now choice of three that I own:

Canon EF 70-200 F4 L
Canon EF 135 F2 L Prime
Canon EF 100 F2.8 L Macro

Open to other suggestions

Bill, I'd say a wide angle lens would be a good choice, it's much more forgiving if you'll have it mounted on your scope and tracking. Many asto targets encompass a wide field.

Read thru the thread, "You Don't Need a Telescope" in the astro photo sharing section, it's filled with many great shots that don't require an elaborate setup, and getting some early successful shots can help to motivate your interest in this field

Hopefully others more knowledgeable will chime in.

[HaroldC3]

The advantage to piggy-backing is you have less focal length meaning your tracking doesn't have to be as accurate. Once you get more and more focal length your tracking has to be that more accurate and probably get into the world of "guiding". This is assuming you are trying to photography Depp-Space Objects.

If you want to photography the moon and planets then you need all of the focal length you can get.

[dougj7]

below is a link to a freeware program called ccd calculator. It will calculate the field of view according to your camera chip size and your scope/lens focal length.

http://www.newastro.com/downloads/cc...cdcalcfull.exe

[ohata0]

with a dslr, you can hook it up directly to the telescope with an adapter (prime focus). However, because you are using a reflector, you may have to check to see if it's able to achieve focus or not (sometimes reflectors need to be modified using low profile focusers and zero profile adapters).

You'd have to ask around (or contact orion) to find out if your telescope can do prime focus without any modification. Another options is to use a barlow in-between the telescope and the dslr, but that will magnify the focal length and increase your exposure times (might not be what you want...unless you're shooting planets)

Piggy backing normally uses smaller telescopes, like refractors, or camera lenses. It'll free up your reflector for visual viewing (just don't touch the scope while you're taking pictures). If you don't plan on doing both at the same time, consider getting an adapter that'll let you hook up your dslr directly to the EQ mount (some sort of dovetail plate i think). I'm not sure exactly which one you'd need though. The benefit is you're losing the reflector OTA weight, making your platform more stable.

to the wedding photog, you might want to post in a different section--this is the astrophotography section. you probably wouldn't find many wedding photogs here (i could be wrong).

[Northwoods Bill]

Thanks everyone for the information.

I would assume (but I will check) that the scope should be able to achieve focus. When the Orion was originally bought it was bought with Astrophotography in mind and from what I understand it is the scope that Orion actually recommended.

I spoke with Orion yesterday and they recommended an adapter that allows the camera to hook to the scope but also allows for the use of a regular eyepiece between the camera and the telescope.

[HaroldC3]

I believe Orion was talking about a Tele-Extender. They are good for magnification, if you don't have a barlow but only work on bright objects such as the moon. I tried using one with my 8" SCT and pointing it at Jupiter and it wouldn't even show up for me.

With my T-adapter tube, I can put an eyepiece inside and hook it up to my camera with a t-ring but I had to get a 2" extension tube. I'll take a picture of it when I get off work and post it.

[spit]

i think your asking about prime focus or afocal, prime focus IMO is better, which brings focusing a DSLR into issue using a newt- i dont bother with newts anymore- so you might need some kind of low profile focuser or adaptor, someone with more newt experience can tell you what exactly- plus your t-ring and t-adaptor for prime- other then that- some people re-set the primary mirror, which probably is less costly