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#1
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I don't like my scope :-(
I have the Orion 8" Skyquest Dobsonian. I have a few issues with it:
1) When I find an object I like to look at (like when Mars was really close last year - remember that?) and I use the eyepiece that views wide (10 mm); everything looks pretty far away. 2) When I use the higher power eyepiece (25mm) the objects move out of view so darn quickly. Does anyone here enjoy his/her Dobs? What kind of stuff do you look at with it? -- ____________________________ Pear pimples for hairy fishnuts? |
#2
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the eyepiece that views wide (10 mm)
the higher power eyepiece (25mm) About on par for a Penguin. |
#3
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Than you shouldget a EQ munt with an RA drive, for tracking.
JS wrote in message . com... I have the Orion 8" Skyquest Dobsonian. I have a few issues with it: 1) When I find an object I like to look at (like when Mars was really close last year - remember that?) and I use the eyepiece that views wide (10 mm); everything looks pretty far away. 2) When I use the higher power eyepiece (25mm) the objects move out of view so darn quickly. Does anyone here enjoy his/her Dobs? What kind of stuff do you look at with it? -- ____________________________ Pear pimples for hairy fishnuts? |
#4
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"Szaki" wrote in
news:rivWb.282858$na.446275@attbi_s04: Than you shouldget a EQ munt with an RA drive, for tracking. JS The whole point of a Dob is to get a lot of optical bang for your buck. A driven equatorial mount that can cope with an 8" f6 newt is going to cost more than he has already paid for his scope. L. wrote in message . com... I have the Orion 8" Skyquest Dobsonian. I have a few issues with it: 1) When I find an object I like to look at (like when Mars was really close last year - remember that?) and I use the eyepiece that views wide (10 mm); everything looks pretty far away. 2) When I use the higher power eyepiece (25mm) the objects move out of view so darn quickly. Does anyone here enjoy his/her Dobs? What kind of stuff do you look at with it? -- ____________________________ Pear pimples for hairy fishnuts? |
#5
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wrote in
. com: I have the Orion 8" Skyquest Dobsonian. I have a few issues with it: 1) When I find an object I like to look at (like when Mars was really close last year - remember that?) and I use the eyepiece that views wide (10 mm); everything looks pretty far away. 2) When I use the higher power eyepiece (25mm) the objects move out of view so darn quickly. er you have it the wrong way around. The 25mm gives you lower magnification than the 10mm. M = F/e where F is the telescope focal length (about 1200mm with your scope) and e is the eyepiece focal length. The 25mm lens will give you a magnification (M) of 48 X. The 10 mm lens gives a magnification of 120 X. Your 8" scope (if properly collimated) can theoretically easily handle magnifications up 400X with appropriate eyepiece and/or barlow combinations. However atmospheric conditions rarely allow you to use such a high magnification. You want to mostly work around the 200 - 250 X level for planetary viewing. Getting a decent 2 X barlow would help you in this regard. Use the 25 mm for viewing star cluters and nebula but don't be afraid to go to a higher mag. Your problem with the object drifting out of the field of view is common to any undriven telescope, you just have to learn to track the object by hand which is not hard if your dob has smooth bearings. It just takes practice. The other option is to add a drive system . This is a possibility even with a dob but will cost. To a google search on Mel Bartels do it yourself Dob goto drive system. Does anyone here enjoy his/her Dobs? What kind of stuff do you look at with it? Love em. Everything. L. |
#6
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First of all you have the wrong idea about your eyepieaces, the 10mm is the high
power one, the 25mm is low power. Also remember the higher the power, the SMALLER the field of view you'll get, so when you push the power up, the object is going to move out of the FOV faster. Last spring I was using my 4.8 neggler on mars and almost had to keep the scope moving, but what I did was to place the view to one side and let mars itself come in and cross the fov. My Dob is a F8 8inch and I've looked at all kinds of Deep Space Objects, planets, just about anything I can fine. And when my truck runs again, I'll be using it once more for Sidewalk Astronomy. -- "In this universe the night was falling,the shadows were lengthening towards an east that would not know another dawn. But elsewhere the stars were still young and the light of morning lingered: and along the path he once had followed, man would one day go again." Arthur C. Clarke, The City & The Stars SIAR www.starlords.org Telescope Buyers FAQ http://home.inreach.com/starlord World of Dahlias Slideshowv1.0 $10.00 for Windows machines. Email: wrote in message . com... I have the Orion 8" Skyquest Dobsonian. I have a few issues with it: 1) When I find an object I like to look at (like when Mars was really close last year - remember that?) and I use the eyepiece that views wide (10 mm); everything looks pretty far away. 2) When I use the higher power eyepiece (25mm) the objects move out of view so darn quickly. Does anyone here enjoy his/her Dobs? What kind of stuff do you look at with it? -- ____________________________ Pear pimples for hairy fishnuts? --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.581 / Virus Database: 368 - Release Date: 2/9/04 |
#7
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Llanzlan Klazmon The 15th wrote:
er you have it the wrong way around. The 25mm gives you lower magnification than the 10mm. M = F/e where F is the telescope focal length (about 1200mm with your scope) and e is the eyepiece focal length. The 25mm lens will give you a magnification (M) of 48 X. The 10 mm lens gives a magnification of 120 X. Your 8" scope (if properly collimated) can theoretically easily handle magnifications up 400X with appropriate eyepiece and/or barlow combinations. However atmospheric conditions rarely allow you to use such a high magnification. You want to mostly work around the 200 - 250 X level for planetary viewing. Getting a decent 2 X barlow would help you in this regard. Use the 25 mm for viewing star cluters and nebula but don't be afraid to go to a higher mag. Your problem with the object drifting out of the field of view is common to any undriven telescope, you just have to learn to track the object by hand which is not hard if your dob has smooth bearings. It just takes practice. The other option is to add a drive system . This is a possibility even with a dob but will cost. To a google search on Mel Bartels do it yourself Dob goto drive system. Thanks, LK. I am not sure if it is properly collimated; as I have never done so. I assumed that it was perfect right out of the factory. I saw a laser collimator - is it something I should get and use? -- ____________________________ Pear pimples for hairy fishnuts? |
#8
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wrote in message om... Llanzlan Klazmon The 15th wrote: er you have it the wrong way around. The 25mm gives you lower magnification than the 10mm. M = F/e where F is the telescope focal length (about 1200mm with your scope) and e is the eyepiece focal length. The 25mm lens will give you a magnification (M) of 48 X. The 10 mm lens gives a magnification of 120 X. Your 8" scope (if properly collimated) can theoretically easily handle magnifications up 400X with appropriate eyepiece and/or barlow combinations. However atmospheric conditions rarely allow you to use such a high magnification. You want to mostly work around the 200 - 250 X level for planetary viewing. Getting a decent 2 X barlow would help you in this regard. Use the 25 mm for viewing star cluters and nebula but don't be afraid to go to a higher mag. Your problem with the object drifting out of the field of view is common to any undriven telescope, you just have to learn to track the object by hand which is not hard if your dob has smooth bearings. It just takes practice. The other option is to add a drive system . This is a possibility even with a dob but will cost. To a google search on Mel Bartels do it yourself Dob goto drive system. Thanks, LK. I am not sure if it is properly collimated; as I have never done so. I assumed that it was perfect right out of the factory. I saw a laser collimator - is it something I should get and use? It may and should have been perfect from the factory, but they can be knocked out of alignment during shipping, so you should check it. |
#9
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Your problem has nothing to do with collimator. It seems you want automatic
but only has manual. wrote in message om... Llanzlan Klazmon The 15th wrote: er you have it the wrong way around. The 25mm gives you lower magnification than the 10mm. M = F/e where F is the telescope focal length (about 1200mm with your scope) and e is the eyepiece focal length. The 25mm lens will give you a magnification (M) of 48 X. The 10 mm lens gives a magnification of 120 X. Your 8" scope (if properly collimated) can theoretically easily handle magnifications up 400X with appropriate eyepiece and/or barlow combinations. However atmospheric conditions rarely allow you to use such a high magnification. You want to mostly work around the 200 - 250 X level for planetary viewing. Getting a decent 2 X barlow would help you in this regard. Use the 25 mm for viewing star cluters and nebula but don't be afraid to go to a higher mag. Your problem with the object drifting out of the field of view is common to any undriven telescope, you just have to learn to track the object by hand which is not hard if your dob has smooth bearings. It just takes practice. The other option is to add a drive system . This is a possibility even with a dob but will cost. To a google search on Mel Bartels do it yourself Dob goto drive system. Thanks, LK. I am not sure if it is properly collimated; as I have never done so. I assumed that it was perfect right out of the factory. I saw a laser collimator - is it something I should get and use? -- ____________________________ Pear pimples for hairy fishnuts? |
#10
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On Wed, 11 Feb 2004 18:55:47 GMT,
wrote: I have the Orion 8" Skyquest Dobsonian. I have a few issues with it: 1) When I find an object I like to look at (like when Mars was really close last year - remember that?) and I use the eyepiece that views wide (10 mm); everything looks pretty far away. 2) When I use the higher power eyepiece (25mm) the objects move out of view so darn quickly. Ummm.... Low number = high power, high number = low power Does anyone here enjoy his/her Dobs? What kind of stuff do you look at with it? OTOH The idea behind the Dob is a relatively inexpensive light bucket. A while back one of the members of our club built a drive using a pair of stepper motors on a 16 inch Dob. Worked great. He controlled it with a C-64. (I did say it was a while back) You could hear those little motors going THUMP, THUMP, THUMP, but you cold not see any vibration in the image. For serious play he had either a 6" or 8" Schmidt camera. (I've forgotten the size) This was all back in the days of strictly film. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com |
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