christurner
super member
Reged: 06/24/08
Posts: 171
Loc: Nova Scotia, Canada
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Hello all. Thanking you all in advance for any help. The winner will get a free Nova Scotia T shirt! I promise. So here is the situation.
My equipment: LX200 12 ACF and a DSI II Color CCD camera. I have a pretty good understanding of the autosuite software so I do not believe there is an issue there. I have also tried the camera on a Newtonian and it works great, and I can get it to focus. NOW THE ISSUE.
When I use the CCD camera on my LX200 I can never achieve focus. In fact the criss cross lines on the bahtinov are somewhat fuzzy. The masks clearly shows the line straight up the middle on the computer screen with the image coming in through the camera...
Are there any LX200 12 ACF users out there that have an issue focusing with the DSI II camera? I also have the camera mounted through my diagnol. Shouldn't matter right from a focus standpoint?
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Chris and Family
Nova Scotia, Canada
Dark Sky Country
www.spatialenergistics.com
Platforms:
Meade LX200 ACF 12"
newstar 5.1" reflector
26mm plossl meade
13mm Ethos
Kendrick Digi10 Dew System
A wife that understands!
Edited by christurner (10/13/09 01:04 PM)
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Joseph Gillman
Carpal Tunnel
Reged: 12/06/05
Posts: 2768
Loc: Aston, PA
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One reason for fuzziness with the 12" SCT when you don't have it with the Newt is that you haven't allowed proper cooldown. I can't comment on the Bahtinov since I never tried one.
There is plenty of focus travel with the moving mirror design of the SCT/ACF.
Try without the bahtinov first, center a bright star like Vega or Deneb overhead, really center it in a crosshair eyepiece so that it will hopefully show up as a donut on your screen. If you don't see a donut it is because you are WAAAAAAAYYYYY out of focus with the DSI and the donut is too big and dim to be seen on the monitor. When you get nearer to focus the donut will be very distinct. You can check collimation this way too.
I recommend using the diagonal with the DSI camera. For DSLR use, don't use a diagonal.
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dunc.ellliott
sage
Reged: 10/06/06
Posts: 202
Loc: Syston, Leicester,UK
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Hi Chris i had the same sort of troubles as you i have the dsi ii color & a 8" LX200R and a focual reducer helped lots i have a 1-1/4" 0.50 that screws in to the nose of the dsi and the meade f3.3 that i have read will not work with a acf / R scope but i does. I turn on the scope with the 26mm ep in & do the auto align & then turn high precision which is in the setup then telescope menu. Then when you pick say m13 it will slew to a bright star, i then take out the ep and the diagonal & put the dsi in & there is a huge donut on the envisage screen which i focus using the manual knob until the star is a round blob & then click the auto exp button in envisage.
Then i turn the mirror lock on put the bahtinov mask on & use the micro focuser on the autosat handset to focus it. Then press enter on the autostar & it will goto m13 or whatever object you have picked & should be focused. I use the f3.3 reducer all the time now with the smallest adaptor & it goes straight in the back of the micro focuser. I hope this has helped the my first pics of m13 were like the image you put in your post in the beginners imaging forum.
Duncan
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Meade 8" LX200R + Dell Inspiron 1501 + DSI ii color
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christurner
super member
Reged: 06/24/08
Posts: 171
Loc: Nova Scotia, Canada
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Hi Duncan. I was wondering about this also... So for clarity you have a meade 3.3 focal reducer that you use and it helped you get a better focus?
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Chris and Family
Nova Scotia, Canada
Dark Sky Country
www.spatialenergistics.com
Platforms:
Meade LX200 ACF 12"
newstar 5.1" reflector
26mm plossl meade
13mm Ethos
Kendrick Digi10 Dew System
A wife that understands!
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Joseph Gillman
Carpal Tunnel
Reged: 12/06/05
Posts: 2768
Loc: Aston, PA
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The 6.3 reducer-corrector is meant to correct the edges of the field in the original SCT.
The 3.3 reducer is a reducer only.
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christurner
super member
Reged: 06/24/08
Posts: 171
Loc: Nova Scotia, Canada
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So when you say its a reducer. Excuse my ignorance but does that mean it reduces the f10 to a f3.3? I.e. makes rthe scope faster?
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Chris and Family
Nova Scotia, Canada
Dark Sky Country
www.spatialenergistics.com
Platforms:
Meade LX200 ACF 12"
newstar 5.1" reflector
26mm plossl meade
13mm Ethos
Kendrick Digi10 Dew System
A wife that understands!
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Joseph Gillman
Carpal Tunnel
Reged: 12/06/05
Posts: 2768
Loc: Aston, PA
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Well it's not a magic pill but yes it is supposed to make the scope a not-quite-celestron-fastar f/3.3. images are smaller but brighter resulting in faster exposure times and with a wider field of view (as much as can be had with a small chip anyway). It will be fine for a dsi sized chip but not for a DSLR.
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Spoonsize
Vendor/Clothing
Reged: 08/27/04
Posts: 3279
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Chris, if you are using a 2" diagonal, replace it with a 1.25. That is if you feel you must use one in the first place. If you can image without the diagonal that would be a more optimal situation.
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Steve Durham
www.margesmonograms.com
(Marge made me do it)
"Nobody get's in to see the WIZARD, Not Nobody, Not Nohow"
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Spoonsize
Vendor/Clothing
Reged: 08/27/04
Posts: 3279
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Somebody jump in if this is in error.
When you place an eyepiece in the diagonal, the focal plane of the scope falls at the field stop of the eyepiece and the image is magnified by the eyepiece. There is no field stop with the camera and the "chip" is positioned further away from the objective. This will sometimes (in this case) not allow the image to come to focus on the "chip".
By using the smaller or no diagonal, you bring the chip within the focus range of the scope.
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Steve Durham
www.margesmonograms.com
(Marge made me do it)
"Nobody get's in to see the WIZARD, Not Nobody, Not Nohow"
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brianb11213
Carpal Tunnel
Reged: 02/25/09
Posts: 2078
Loc: 55.215N 6.554W
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Quote:
Somebody jump in if this is in error.
What you write is perfectly accurate, though the change in backfocus is irrelevant given the huge range of focus adjustment given by the standard SCT primary mirror focusing mechanism.
I would never use a diagonal in conjunction with a camera - just connect straight to the SCT back port, using a SCT to T thread adaptor or visual back depending on the camera type. If a focal reducer is used, and too much space is between the reducer and the camera sensor, it can become impossible to achieve focus. This is particularly likely if a diagonal is used (because of the back focus requirement) or whan a SLR type camera is used (because the sensor is so far back from the mount flange, necessary to make room for the reflex mirror mechanism).
The combination of short focus (0.33x) reducer, diagonal and SLR camera is guaranteed not to focus on any scope!
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dunc.ellliott
sage
Reged: 10/06/06
Posts: 202
Loc: Syston, Leicester,UK
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Hi Chris the reducer does help me as the fov on the screen is bigger and most things i have tried to image other than m57 are to large without the reducer on my 8" it must be harder on a 12" but a bright star to focus on first i think is a must have. Duncan
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Meade 8" LX200R + Dell Inspiron 1501 + DSI ii color
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LLEEGE
Running out of Oxygen
Reged: 03/03/05
Posts: 9049
Loc: Cloud-chester,NY
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I would try and focus on the moon at prime focus. If that can't be achieved, you have a problem.
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"Okay! You draw the straws. I'm-a taking the parachute."
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Joseph Gillman
Carpal Tunnel
Reged: 12/06/05
Posts: 2768
Loc: Aston, PA
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You will have to get the terminator or the lunar limb onto your dsi field if view. Then you should be able to see if you are moving te focuser in the right direction fairly easily.
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Mystic Hill
member
Reged: 10/29/06
Posts: 32
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Quote:
When I use the CCD camera on my LX200 I can never achieve focus. In fact the criss cross lines on the bahtinov are somewhat fuzzy. The masks clearly shows the line straight up the middle on the computer screen with the image coming in through the camera...
Are there any LX200 12 ACF users out there that have an issue focusing with the DSI II camera? I also have the camera mounted through my diagonal. Shouldn't matter right from a focus standpoint?
Chris,
At the risk of restating the obvious (please forgive me) but does your LX200 have both a microfocuser and a primary focuser or just the primary focuser? As others have said, the primary focuser should give plenty of travel. (unlock the mirror first then relock) I suppose that the diagonal may put the CCD too far back to achieve focus, I always remove mine. It does matter.
If you are only focusing with a microfocuser then there is not nearly enough travel to obtain focus with both an eyepiece and a camera.
If you knew all that then my apologies.
The Bahtinov mask is great.
Roy
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christurner
super member
Reged: 06/24/08
Posts: 171
Loc: Nova Scotia, Canada
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Hey Roy, no problem with your question at all. Sometimes I need to hear it several times in different ways so I really appreciate you asking... I have a microfocuser and the main focus knob on the scope (I assume that is what you are calling the "primary focuser right?) Also I do have the diagnol. So what I have setup now (cloudy for the last few days)is I have removed the microfocuser and I have removed the diagnol. My reducer 3.3 and t adapter are connected together with the camera. Looking forward to trying it out next clear night. I hope it works!
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Chris and Family
Nova Scotia, Canada
Dark Sky Country
www.spatialenergistics.com
Platforms:
Meade LX200 ACF 12"
newstar 5.1" reflector
26mm plossl meade
13mm Ethos
Kendrick Digi10 Dew System
A wife that understands!
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Spoonsize
Vendor/Clothing
Reged: 08/27/04
Posts: 3279
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Chris:
I will be difficult at best to get a good focus this way although it can be done. A homemade focusing mask will help. It might be easier to just remove the diagonal if that is possible, it may not be with the threads on the reducer, I've not tried. Looking forward to hearing of your results.
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Steve Durham
www.margesmonograms.com
(Marge made me do it)
"Nobody get's in to see the WIZARD, Not Nobody, Not Nohow"
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christurner
super member
Reged: 06/24/08
Posts: 171
Loc: Nova Scotia, Canada
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yes i do plan on using this configuration with the bahtinov mask to achieve focus. Thats what you mean right?
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Chris and Family
Nova Scotia, Canada
Dark Sky Country
www.spatialenergistics.com
Platforms:
Meade LX200 ACF 12"
newstar 5.1" reflector
26mm plossl meade
13mm Ethos
Kendrick Digi10 Dew System
A wife that understands!
|
Spoonsize
Vendor/Clothing
Reged: 08/27/04
Posts: 3279
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Yup.
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Steve Durham
www.margesmonograms.com
(Marge made me do it)
"Nobody get's in to see the WIZARD, Not Nobody, Not Nohow"
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