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Daniel
scholastic sledgehammer
Reged: 06/16/05
Posts: 908
Loc: Roscoe,IL
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I used my Meade Video ep the other day on a black and white 12" monitor I have for the set up. I noticed a HUGE increase in the grains on the surface, and less on the way of seeing the flares on the edge. I could see them but they seemed more "out of reach" than other details on the surface.
I was really quite taken by the views seen with this video ep versus visual.
Has anyone else noticed this? I am wondering why it is that I encountered this?
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Looking for a big ol Dobsonian..12-16"
ETX 70mm,F5
Bushnell 7-21x40 bino's
Barska 20x80mm Binos
Meade Video Eyepiece
Canon A-E1 SLR,Canon EOS ElanII
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Doug D.
Carpal Tunnel
Reged: 08/23/05
Posts: 1862
Loc: Virginia
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Its been a while since I owned the Meade EEP and used it with the PST, but if I remember correctly, you could see prominences if you adjusted the EEP dial so that surface details were way overexposed. So, you can see the detail at the limb or at the surface but not both at same time - more or less. At least that is what I remember.
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Hooville
AP 105EDF f/6 Traveler; AP 140 EDF StarFire f/7.5; TV 76 f/6.3 with Solarscope SF70 filter; Solarscope Solarview 50; Coronado CaK 70; Orion XT-10; Baader Mk V & ZAO II's; Half-Hitch Mk II; Astrotrac TT320X, pier & wedge; AP Mach1GTO; PGR Flea 2
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NickH
Post Laureate
Reged: 05/09/06
Posts: 3717
Loc: Wiltshire, UK (near StoneHenge...
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It works well with a moon filter on it i found...
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 8289
Loc: Beatrice, Nebraska
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Quote:
I used my Meade Video ep the other day on a black and white 12" monitor I have for the set up. I noticed a HUGE increase in the grains on the surface, and less on the way of seeing the flares on the edge. I could see them but they seemed more "out of reach" than other details on the surface.
I was really quite taken by the views seen with this video ep versus visual.
Has anyone else noticed this? I am wondering why it is that I encountered this?
This is due to the automatic gain control (AGC) in the camera. It changes the sensitivity of the camera depending on how much total light is being picked up. To prevent excessive blooming or oversaturation, the gain is reduced when most of the solar disk is covering the frame, making dark detail stand out somewhat better. Unfortunately, this means that the fainter limb detail vanishes, as the camera's gain has been lowered. When you move most of the solar disk out of the field, the AGC detects less light in total and kicks up the gain of the camera to compensate. This allows you to now see the fainter limb details like prominences, although detail just inside the limb is now way overexposed. In a perfect world, the video eyepiece would have a manual gain control option, but I guess it isn't a perfect world. Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org
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Daniel
scholastic sledgehammer
Reged: 06/16/05
Posts: 908
Loc: Roscoe,IL
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The Meade EP I have has a manual gain on it. I can tune it like Doug says, to get the prom's to stick out. I like the idea of possibly trying a moon filter on the vid.ep. to see what I get.
I guess the point here is that I think there are advantages to looking with video ep's. I used the LPI in live mode and did not see this, or anywhere near it. The live video was the way to go.
Has anyone tried hooking up a regular video camera? I wonder if the effect is the same without a ccd chip. Probably not.....
Anyways, thanks for the suggestions!
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Looking for a big ol Dobsonian..12-16"
ETX 70mm,F5
Bushnell 7-21x40 bino's
Barska 20x80mm Binos
Meade Video Eyepiece
Canon A-E1 SLR,Canon EOS ElanII
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 8289
Loc: Beatrice, Nebraska
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Quote:
The Meade EP I have has a manual gain on it. I can tune it like Doug says, to get the prom's to stick out. I like the idea of possibly trying a moon filter on the vid.ep. to see what I get.
I guess the point here is that I think there are advantages to looking with video ep's. I used the LPI in live mode and did not see this, or anywhere near it. The live video was the way to go.
Has anyone tried hooking up a regular video camera? I wonder if the effect is the same without a ccd chip. Probably not.....
Anyways, thanks for the suggestions!
The Meade Electronic Eyepiece has a *contrast* control, but the units I have seen still use an AGC system to control the gain of the camera. There are some TV cameras which do have manual gain, but the simple small ones still tend to have automatic gain control as a non-defeatable feature. I have an old Vidcon tube color camera which I used for H-alpha work, and it too had the older AGC system in it as well. Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org
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Daniel
scholastic sledgehammer
Reged: 06/16/05
Posts: 908
Loc: Roscoe,IL
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Ahhh I sit corrected. I guess there is a difference between the two. HEY.... I'm just a dumb bricklayer, whatya expect. I plug it in and go ....ahhhh ahahaha (Steve Allen Grunt)
Other than that.. if it dont work right I hit it with a hammer!!
Thanks for settin me straight on that. I did not really know the difference between the two, or should I say... did not pay attention to the two.
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Looking for a big ol Dobsonian..12-16"
ETX 70mm,F5
Bushnell 7-21x40 bino's
Barska 20x80mm Binos
Meade Video Eyepiece
Canon A-E1 SLR,Canon EOS ElanII
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