Focal reducer on a C11

[bones]

Hi all, this is my first thread so I'll see how I go. I purchased a Celestron C11 last year. I have had a bit of a go at astrophotography starting with the basics really, with some afocal and prime focus shots through my wife's Nikon D40. Reading the info that's around my understanding is that a focal reducer can reduce the exposure time required, and also makes the field of view larger through the eyepiece. My scope has a focal ration of f/10 and when I tried doing prime focus shots on the moon with a 2" step adaptor I wasn't able to get the whole moon in the shot. In the future I'm looking at getting a f6.3 focal reducer but I'm wondering if I did if I'd be able to see the whole of the moon in the field of view. Has anyone out there had this kind of problem? Is a focal reducer worth it?

[[1ponders] (Paul)]

Hi bones.

If your chip size is similar to the D70 and using a 6.3 FR you may just be able to fit it into the FOV. If its much larger then you probably wont fit it in.

[Matty P (Matt)]

Hi Bones,

I recently just purchased a f/6.3 focal reducer for my C8 and love it. The focal reducer reduced my scopes focal length to 1260mm giving me a much wider FOV. I'm using it mostly for imaging but the visual views are definitely worth it.

The FR should reducer should reduce your scopes focal length enough so that the whole Moon will fit in the EP.

[[1ponders] (Paul)]

Here's a screen dump of what you would most likely get with a C11-.63-D70 combo.

BTW what do you mean by a "Step adapter"?

[bones]

Thanks for the quick replies guys. I'll have to check out the chip info between the two camera's when I get a chance. From the response thus far, the f/6.3 reducer seems to be worth the cost. In relation to the step adaptor, it's an adaptor I bought that attaches the camera directly to the diagonal, i.e. no eyepiece involved. I'm a bit wary when I use it because when the camera's not attached to the diagonal the inside of the camera is exposed to the elements.

[[1ponders] (Paul)]

Ok, I've got you now, it would be a T-thread-1.25" nose piece. Using this you won't get a very good moon shot due to the narrowness of the adapter. If you get a 6.3 reducer you will also need to get a T adapter. This will connect the CS thread at the back of the reducer to the T thread of your camera T ring.

Alternatively you could try the prime focus adapter by unscrewing the silver end, screwing that onto one side of the reducer and the other piece onto the male side of the reducer. This will then screw directly into your camera T ring. The only issue is the 6.3 FR needs about 105mm of distance from the rear element to operate at its best. The T adapter attached to you T ring will give you just about the right distance.

[bones]

1ponders, the T-Thread 1.25" nose piece you mention seems to describe the adaptor I used. I take it from what you're saying I don't use this one the moon in the setup at all, but say use the focal reducer and the T adaptor you mention instead? Looking into your first response a bit more about the chip size on the camera what is this in simple terms?

[[1ponders] (Paul)]

I take it from what you're saying I don't use this one the moon in the setup at all, but say use the focal reducer and the T adaptor you mention instead?

That's right. Leave the 1.25" adapter out of it altogether. The Reducer will screw directly to the the back of your C11 and the T adapter will screw directly to the Reducer and the T adapter will screw into your camera T ring.

I used to have a photo somewhere showing how it all went together. I'll see if I can dig it up.

Your chip size; how big is it in mm x mm or pixel x pixel (I would also need to know the pixel pitch as well in this case)

[[1ponders] (Paul)]

Ok found this old link.
http://www.iceinspace.com.au/forum/a...se.php?a=16188

Ignore the SC Adapter ( I used to have an LX200 with the microfocuser and the SC Adapter went into there). If you have a zero shift focuser attached then you should have one of these adapters with your focuser.