George, I was actually measuring the opening in an extra extension tube I don't use and that's 3 1/8" ID. I hadn't thought about the baffle tube. My rig stays setup all the time in the OB so I probably won't take it apart to see. That is, until my new camera arrives next month. It will be interesting to see if I have a problem then...it has a 8.3 mp chip.
Thanks for the information. Actually, the opening in my rear casting is 2 1/8" which the light cone has to get through. If you unscrew the 90mm diameter screw-on extensions from the rear casting you can see the 2 1/8" opening. Please advise if you find that the actual opening in your rear casting is around 3". That would be an interesting and desirable design change. Keep in mind that the baffle tube rearward of the secondary mirror is probably 2 1/2" or so in diameter and that would then be the light cone restriction point.
I was surprised to see no noticeable vignetting with my ST-2000. When I put on my FLI with a much larger chip some vignetting might be evident.
George K.
From: ATTelescopes@yahoogroups.com [mailto:ATTelescopes@yahoogroups.com] On Behalf Of Stu Beaber Sent: Saturday, November 21, 2009 8:27 AM To: ATTelescopes@yahoogroups.com Subject: Re: [ATTelescopes] Received My AT8RC
George, there may be a little more activity on another AT group at:
There you can see some of my pix as well as others. I've had mine (AT8RC) a couple 2 months I guess and so far have nothing to complain about. My back focus with the ST-8 is about the same as yours (~10.5") and have no noticable vignetting with that size chip. My opening is ~3 1/8".....you may have hit a wrong key. My collimation was right on 'out of the box' as far as I could tell. If I had any complaint, it would be how easy that beautiful carbon fiber tube scratchs. I have about a 1" scratch on the side from an encounter with a screw driver :^(
Just wondering if anyone is around. I received my new AT8RC about a month ago. Stars were bad at first due to the scope being out of collimation. I collimated it at powers up to 500 and the stars were greatly improved and round to the edge of an SBIG ST-2000 CCD camera. Need to do much more testing when skies clear to arrive at any conclusions as to quality and performance.
The back focus distance behind the rear casting of 10 3/4" is really surprising and caused concern because the opening in the rear casting is only 2 1/8" in diameter. However, early tests do not show cut-off of light cone or vignetting from this source when using the ST-2000.
Thanks for the information. Actually, the opening in my rear casting is 2 1/8" which the light cone has to get through. If you unscrew the 90mm diameter screw-on extensions from the rear casting you can see the 2 1/8" opening. Please advise if you find that the actual opening in your rear casting is around 3". That would be an interesting and desirable design change. Keep in mind that the baffle tube rearward of the secondary mirror is probably 2 1/2" or so in diameter and that would then be the light cone restriction point.
I was surprised to see no noticeable vignetting with my ST-2000. When I put on my FLI with a much larger chip some vignetting might be evident.
George K.
From: ATTelescopes@yahoogroups.com [mailto:ATTelescopes@yahoogroups.com] On Behalf Of Stu Beaber Sent: Saturday, November 21, 2009 8:27 AM To: ATTelescopes@yahoogroups.com Subject: Re: [ATTelescopes] Received My AT8RC
George, there may be a little more activity on another AT group at:
There you can see some of my pix as well as others. I've had mine (AT8RC) a couple 2 months I guess and so far have nothing to complain about. My back focus with the ST-8 is about the same as yours (~10.5") and have no noticable vignetting with that size chip. My opening is ~3 1/8".....you may have hit a wrong key. My collimation was right on 'out of the box' as far as I could tell. If I had any complaint, it would be how easy that beautiful carbon fiber tube scratchs. I have about a 1" scratch on the side from an encounter with a screw driver :^(
Just wondering if anyone is around. I received my new AT8RC about a month ago. Stars were bad at first due to the scope being out of collimation. I collimated it at powers up to 500 and the stars were greatly improved and round to the edge of an SBIG ST-2000 CCD camera. Need to do much more testing when skies clear to arrive at any conclusions as to quality and performance.
The back focus distance behind the rear casting of 10 3/4" is really surprising and caused concern because the opening in the rear casting is only 2 1/8" in diameter. However, early tests do not show cut-off of light cone or vignetting from this source when using the ST-2000.
There you can see some of my pix as well as others. I've had mine (AT8RC) a couple 2 months I guess and so far have nothing to complain about. My back focus with the ST-8 is about the same as yours (~10.5") and have no noticable vignetting with that size chip. My opening is ~3 1/8".....you may have hit a wrong key. My collimation was right on 'out of the box' as far as I could tell. If I had any complaint, it would be how easy that beautiful carbon fiber tube scratchs. I have about a 1" scratch on the side from an encounter with a screw driver :^(
Just wondering if anyone is around. I received my new AT8RC about a month ago. Stars were bad at first due to the scope being out of collimation. I collimated it at powers up to 500 and the stars were greatly improved and round to the edge of an SBIG ST-2000 CCD camera. Need to do much more testing when skies clear to arrive at any conclusions as to quality and performance.
The back focus distance behind the rear casting of 10 3/4" is really surprising and caused concern because the opening in the rear casting is only 2 1/8" in diameter. However, early tests do not show cut-off of light cone or vignetting from this source when using the ST-2000.
Just wondering if anyone is around. I received my new AT8RC about a month ago. Stars were bad at first due to the scope being out of collimation. I collimated it at powers up to 500 and the stars were greatly improved and round to the edge of an SBIG ST-2000 CCD camera. Need to do much more testing when skies clear to arrive at any conclusions as to quality and performance.
The back focus distance behind the rear casting of 10 3/4" is really surprising and caused concern because the opening in the rear casting is only 2 1/8" in diameter. However, early tests do not show cut-off of light cone or vignetting from this source when using the ST-2000.
Greetings All:
I'm new to the ATT group. I'm Joe, I live near Easton PA and am a nmember of
the Lehigh Valley Am. Astro Society... Are any other group members attending
NEAF this weekend? Perhaps we could meet up at the show. Cheers, Joe.
Hi Bob and the ATT Group:
I realize that posts have been scarce, but even as a new member I feel that
the commercial Social Networking posts (like the several previous to this)
should be deleted. Bob , if you are too busy to do this, I will volunlteer to do
it for the time being.
Warm weather is upon us, people wioll be receiving new scopes and post will
increase. Lets keep off topic posts to a minimum! Joe.
Still waiting for them to arrive. I am also waiting on the new
shipment of AT80EDT's, the aluminum tubed white one, not the graphite
tubed black one. One of those has my name on it. Supposed to be in
about OCT4. Maybe the RC's will come in then also.
Doug
Not a one, as they are not yet out. Hello, just found this, and joined.
There is another AT group, you know?
Doug
--- In ATTelescopes@yahoogroups.com, "flobserver" <douglozen@...> wrote:
>
> Any reviews yet?
>