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Agreed, plus much easier collimation

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I would like to know where this came from because this isnt the first time I've read this statement. I have 2 newts and 2 sct's and the sct's are by far easier for me to collimate. There are only 3 screws, thats it. No centering the secondary, then aligning the secondary, then aligning the primary. I suppose it comes from people that laser collimate because you cant use a traditional laser on a sct? Bottom line, for me anyway, the sct is way easier to collimate. I can get them very close with the eyeball in daylight and then its 3 simple screws to adjust on a star when its dark. I collimated my 8" and 10" sct's when I received them and havent touched them since. Always fiddling with the newts so reguardless I think this point is moot.

Anyway, just wanted to get that off my chest. If I could have only 1 scope and had to choose between a 12" SCT or a 12.5 Obsession I'd take the dob, hands down. I'm looking into getting a 15"-20" myself right now. Let us know what you choose.

Oh BTW, Go ask the same question in the SCT section and see what answers you get.

Edited by rflinn68 (08/11/12 07:23 PM)

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Always fiddling with the newts so regardless I think this point is mute.

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As quiet as you may be, I think you meant "moot".

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Having owned a 12" Meade LX200, I am considering a 12.5 Obsession but the more I think about it, I wonder what the difference in views between the two will be ( I know about the F5 vs F10 focal ratios) if both are adjusted to the same power views, say 100 power ( 30 mm eyepiece in Meade, 15 mm in Obsession). Reasoning is that a used LX200 is a lot cheaper than an Obsession equipped with tracking

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That's a straw man. You could compare the used LX200 with a used Obsession. Then the Obsession is cheaper. You don't need tracking and GoTo, but Digital Setting Circles (DSC) are nice to allow you to find faint targets (we call it "Push To")

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and the Meade is only about 20 lbs more to lift into the car.

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No one lifts a 12.5" Obsession as a single unit, so the heaviest part is roughly 1/3 the weight of a 12" LX200. In terms of lifting into a car, a 12" LX200 takes a VERY strong person, whereas a 12.5" Obsession could be handled by a smallish woman who doesn't lift weights as a hobby.

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so why buy the Obsession? (Help convince me, I really want to try a dob). P.S. Please don't say go bigger, a 12" is all I can handle or transport.
Your thoughts are kindly requested, thanks.
Rex

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The advantages of the dob:
--lighter!!!
--brighter image (2 reflective surfaces versus 3 reflective and 2 refractive)
--larger field of view
--better image quality from smaller secondary obstruction.
--better optics
--faster cooling
--no image shift when focusing
--dob fits in a smaller car
--better eyepiece position (seated viewing at all altitudes)
--fun making modifications to "personalize" the scope--hard to do on an SCT.

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Thanks Don, and everyone,
In all the reading on this site and the Amart one, I can not recall anyone doing a comparsion between the optic quality of a sct and a dob, I always asumed the sct had the better optics and the dob was chosen for its light gathering ability and size. I will definitly consider a 12" dob for its optics now and probably forgo the goto ( I have a push to mount - Diskmount DM6 , so I am used to that method of finding my way around the sky).
Rex

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Agreed, plus much easier collimation

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I would like to know where this came from because this isnt the first time I've read this statement. I have 2 newts and 2 sct's and the sct's are by far easier for me to collimate. There are only 3 screws, thats it. No centering the secondary, then aligning the secondary, then aligning the primary. I suppose it comes from people that laser collimate because you cant use a traditional laser on a sct? Bottom line, for me anyway, the sct is way easier to collimate. I can get them very close with the eyeball in daylight and then its 3 simple screws to adjust on a star when its dark. I collimated my 8" and 10" sct's when I received them and havent touched them since. Always fiddling with the newts so reguardless I think this point is mute.

Anyway, just wanted to get that off my chest. If I could have only 1 scope and had to choose between a 12" SCT or a 12.5 Obsession I'd take the dob, hands down. I'm looking into getting a 15"-20" myself right now. Let us know what you choose.

Oh BTW, Go ask the same question in the SCT section and see what answers you get.

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I find it very easy to collimate my Newts. It's always just a 1 min touch up when i take mine outside. Now if everything is way out of wack then it can be a pain the first time around. SCT's i just always use a star at 300 to 600x.

Chas

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Always fiddling with the newts so regardless I think this point is mute.

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As quiet as you may be, I think you meant "moot".

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yes ...Thanks Don. You know I cant make it through a day without 4 or 5 screw-ups. I think this is the 1st today but only because I slept in today

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Having owned a 12" Meade LX200, I am considering a 12.5 Obsession but the more I think about it, I wonder what the difference in views between the two will be ( I know about the F5 vs F10 focal ratios) if both are adjusted to the same power views, say 100 power ( 30 mm eyepiece in Meade, 15 mm in Obsession). Reasoning is that a used LX200 is a lot cheaper than an Obsession equipped with tracking

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That's a straw man. You could compare the used LX200 with a used Obsession. Then the Obsession is cheaper. You don't need tracking and GoTo, but Digital Setting Circles (DSC) are nice to allow you to find faint targets (we call it "Push To")

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and the Meade is only about 20 lbs more to lift into the car.

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No one lifts a 12.5" Obsession as a single unit, so the heaviest part is roughly 1/3 the weight of a 12" LX200. In terms of lifting into a car, a 12" LX200 takes a VERY strong person, whereas a 12.5" Obsession could be handled by a smallish woman who doesn't lift weights as a hobby.

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so why buy the Obsession? (Help convince me, I really want to try a dob). P.S. Please don't say go bigger, a 12" is all I can handle or transport.
Your thoughts are kindly requested, thanks.
Rex

---

The advantages of the dob:
--lighter!!!
--brighter image (2 reflective surfaces versus 3 reflective and 2 refractive)
--larger field of view
--better image quality from smaller secondary obstruction.
--better optics
--faster cooling
--no image shift when focusing
--dob fits in a smaller car
--better eyepiece position (seated viewing at all altitudes)
--fun making modifications to "personalize" the scope--hard to do on an SCT.

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Thanks Don, and everyone,
In all the reading on this site and the Amart one, I can not recall anyone doing a comparsion between the optic quality of a sct and a dob, I always asumed the sct had the better optics and the dob was chosen for its light gathering ability and size. I will definitly consider a 12" dob for its optics now and probably forgo the goto ( I have a push to mount - Diskmount DM6 , so I am used to that method of finding my way around the sky).
Rex

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If you get a top end Dob with a Zambuto or OMI mirror it will kill a SCT everytime. Can't even come close. There are also other great mirror makers out there besides Zambuto and OMI.

The low end stuff that sells for cheap is pretty much junk in my book and i would stay away from the cheap mass produced Dobs.

Chas

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but in reply to a bigger dob, I have only two words:
Mini Cooper
Rex

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but in reply to a bigger dob, I have only two words:
Mini Cooper
Rex

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Is that a newer "Big" one or one of the origional "Real" ones? ; )

Regardless a 16" Starmaster will fit in one of the newer minis. In fact on amart there is one for sale that has ridden in a mini.

Bill

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Newer Big one! but even with the seats folded down, by the time I put a spare tire in the back ( you thought it came with one? or even a place to put one? no!) there is not that much space for a big scope.
Rex

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The low end stuff that sells for cheap is pretty much junk in my book and i would stay away from the cheap mass produced Dobs.

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If I lived in Fla I would buy a Starstructure 12.5". He's like in your backyard almost.

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Agreed, a 12.5" with Zambuto primary is really a sweet scope
http://www.starstructure.com/starstructure3_002.htm

When I get too old and weak to handle my 18" that's I'm getting.

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I would like to know where this came from because this isnt the first time I've read this statement. I have 2 newts and 2 sct's and the sct's are by far easier for me to collimate. There are only 3 screws, thats it. No centering the secondary, then aligning the secondary, then aligning the primary.

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If I lived in Fla I would buy a Starstructure 12.5". He's like in your backyard almost.

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On a semi-unrelated note, this is one aspect i find seriously appealing about the "Spica Eyes" Dob with its "Slipstream" go-to drive... as is being discussed in a concurrent thread. A full go-to Dob, able to be grabbed & slewed manually at any point... without losing its settings!
Schweet!

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If I lived in Fla I would buy a Starstructure 12.5". He's like in your backyard almost.

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Agreed, a 12.5" with Zambuto primary is really a sweet scope
http://www.starstructure.com/starstructure3_002.htm

When I get too old and weak to handle my 18" that's I'm getting.

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I could live with a 12.5" F/5 SS Dob, or better yet a 14.5" F/6 for my planet viewing.

Chas

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Can't comment on the Meade, but I love my Obsession 12.5". I am almost 68 and find no problems with handling the weight of the mirror box. This is one reason I got the 12.5" rather than a larger Obsession. One suggestion: get one with the handles, very handy for moving the box around. Its easy enough to lift out of the back of the SUV and heft a short distance, but can be a pain to move any great distance unless you are young and strong. I cart mine out to the backyard on occasion but mostly use it at dark sky sites.

Ed

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