Reducer for EdgeHD

[MytThor]

I see on the Celestron web, the Edge HD reducer is $599. It will only provide ONE f/stop faster... really, for 600 dollars? f/10 to f/9... that's not a lot to brag about for just a few more seconds if you are doing AP. Am I missing something?

[Bob327]

I sure can understand your (and mine) reaction to the price...BUT I think the reducer is going to drop the f stop down to to the normal reducer range of f/6 or so..

I'm not sure however... as my scope is not an edge scope nor do I have any interest in AP..

Bob G

[MytThor]

The normal f/stop range is what I thought at first... but they only say "One Full f/stop", without telling you what the final f/stop would be . So I was thinking they were trying to fool people who didn't know a lot about photography.

[Tim K]

Exposures with the reducer are shortened by a factor of 0.7x0.7=0.49, or about half. Is it worth $600? How much is your time worth? If you only have 8 hours a month available for AP, the reducer could give you the equivalent of 16.

[Phil Leigh]

One full stop = half the exposure time. F10 to F9 is NOT one stop! F10 to F6.3 is one stop.

[MytThor]

Oh... Must be having one of those days. Don't know what I was thinking, f/11 would be f/8... So f/10 would surly be f/6.3. Thanks for setting me straight!

[ChuckWalters]

The reducer is worth every penny if you are going to do any AP with your scope. To get from f/10 to f/6.3 and preserve the quality of the edge is worth it.

[CoolBreeze]

f/10 to f/6.3 is "one stop". What is the definition of one stop? I know f/6.3 is faster than f/10 but I'm not clear on how one stop gets a telescope to that and what a "stop" is.
Thanks.

[ChuckWalters]

Modern lenses use a standard f-stop scale, which is an approximately geometric sequence of numbers that corresponds to the sequence of the powers of the square root of 2: f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/45, f/64, f/90, f/128, etc. Each element in the sequence is one stop lower than the element to its left, and one stop higher than the element to its right. An 11 drops to an 8 and a 10 drops to a 6.3 in stop range.

[Joel_L]

Hi,

I just got mine today. As someone mentioned, the HD version is .7x not .63x as the reducer/flatteners are for the non HD tubes. It weighs a ton, will definitely need weight added to the front of the tube. The reducer + T-adapter + camera is a lot of weight hanging off the back. Of couse now that I have it, I'm stuck with cloudy skies again. BTW, I believe it will also work well for visual use and provide a wider field of view or a given EP.

Joel