The 10" Dobsonian Equatorial Telescope

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bbrock

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All<br /><br />I just wanted to report what could have been a big mistake. I purchased an Orion XT10 Dob and love it. I have seen ads for Equatorial Platforms and considered purchasing one to try it. Reading further, I found out that the platforms are taylor made for your approximate latitude. I didn't like the idea of being tied down to an approximate latitude.<br /><br />I was looking through the Orion order book and noticed the Atlas 10 telescope looked exactly like the XT10. I contacted Orion and asked if the XT10 tube could be mounted on the Atlas mount. They thought I would possibly need to remove the Dob mounting hubs. I thought I would try it, and not remove the hubs.<br /><br />I ordered the Atlas Equatorial Mount along with the mounting rings for the 10" tube and an extra 11 lb counter weight. All for about $200 less then the cost of an equatorial platform. The whole thing worked great. I didn't have to remove the Dob mounting hubs, they were well inside the mounting rings. The scope balanced beautifully. The extra 11 lb weight was needed. ( 33 lbs of total counterweight. )<br /><br />Tonight was the first time I have used it. I took great care to polar align and level. The tracking was tack on target. Just to test it I used 400x on the ring nebula and let it run for 30 minutes. I didn't see any drift at all. For the record, I then lifted the tube out of the equatorial mounting rings and set it on the Dob Base -- Just to say I did it. <br /><br />I'm probably not the first person to do this, but I haven't heard anyone else mention doing it. <br /><br />Im lucky ( In hind sight ) to have purchased the Dob first. If I purchased the Atlas 10 first, I don't know if I could have added the hubs and purchased the Dob base later. <br /><br />Just thought someone might like to know this alternative. <br /><br />Bill
 
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nevers

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Very good post Bill...! I've wondered about this option and was told it wouldn't work. But, now I know better: Thanks! My only thought now is....hmmm?<br /><br />I think the mount is battery powered, is there an option of using an external battery? Can you tell us about it when you get a chance?
 
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bbrock

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Brad<br /><br />Sorry about the delay getting back to you. I've been on a deer hunt. You can use the battery pack supplied with the mount. I ignored it ( 8 D cells indeed ) I'm using an Orion Dynamo Pro 17. Any 12v external battery will do. You can use your vehicle cigarette lighter output if you like. <br /><br />What I like about the Atlas is it is very beefey and so quiet you have to put your ear up to it to hear it. The down side is the highest tacking speed is 16x sideral. However, there are the two unlock levers that let you move the mount around in RA and DEC to rough point the tube with either the finder scope or EZ Pointer, lock the tube back into tracking and use the hand control to go from there. <br /><br />This is one hell of a beefey mount. The hole unit with the tube will go over 120 lbs. <br /><br />Bill
 
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ryang

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Hi,<br />Thanks for your information. I am new to telescope ownership and am cosidering the XT8, the XT10 or skyview pro 8 EQ (http://www.telescope.com/shopping/product/detailmain.jsp?itemID=1148&itemType=PRODUCT&iMainCat=4&iSubCat=8&iProductID=1148). Do you have any thoughts on the value of tracking and intelliscope? I couldnt set up a unit as described here fot tracking because i will need to move the scope around and that would be too heavy for that. The Orion skyview 8 EQ does tracking, but wont do the intelliscope for help finding objects. Also, I am told that the X8/X10 are better because of the focal length. I am just trying to understand whether using intelliscope is worth it since there are cheaper x8/x10 that dont support that. Then the whole tracking part is another unknown for me. How fast do the objects pass through view? Is it a big effort to keep up? I dont think ill be doing any astrophotography, just checking everything out tht I can find in the sky.<br /><br />Any input here is greatly appreciated. Funny, I called Orion and the sales person hadn't used telescopes, so they jut looked up things in the manuals. It wasnt too hepful.<br /><br />Thanks,<br />Ryan
 
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bbrock

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Ryan<br /><br />Your questions and interests are common. I'll try to give it justice. I will make this simple. The Intelliscope works OK, as do other GOTO telescope computers. I purchased the Orion XT10 Intelliscope. I have use the Intelliscope about 5 times, and now I don't use it at all. <br /><br /> Let me Explaine. If you move to a new town, you get a map and ask directions to the local drugstore and grocery store. Once you found these, you don't use the map any more. You will find out that locating objects in the night sky is simple. <br /><br /> I suggest you do two things. Save the ($149 + Tax + shipping ) you will spend on the Intelliscope and purchase 1) Starry Night software and 2) a decent pair of 50mm aperature binoculars, such as 10x50's. Starry Night will locate for you any object in the night sky at any time of day, month or year withing a near perfect star field out to magnitude 11 stars. Stary Night software is the best GOTO you will ever own. Take the binoculars outside and look to precisely the same star field to find the clusters, nebula and galaxies identified for you by Starry Night. Most of the time you can see the faint blur images in the 10x50 binoculars. Now you are set to point your telescope at the same star field at the same location. If you depend heavily on a GOTO computer and you are off by 1 or 2 degrees -- for any reason, you won't know where to look and think you are doing something wrong with the telescope. <br /><br /> GOTO computers such as the Intelliscope are rarely dead on and often targets are just outside the field of view. But Where? I used the intelliscope for two night trying to find the Ring Nebula. I didn't know if I was using too much magnification, too little or if I needed a nebula filter. I gave up. I decided to memorize the exact location and star field and point the telescope on the exact spot. Bingo. The ring nebula is a small planitary nebula easily missed but easy to see without a filter.
 
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ryang

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Hi Bill,<br /><br />Thanks for the great information. Since I want my kids to be able to look at the skies as well, I think the tracking is must for me. I will most likely forgo the intelliscope. <br /><br />Do you have any opinions on the differences between the xt8 and the skyview 8 eq? The Skyview 8 seems great for me, but I don't want to miss something that I would like further down the road. <br /><br />Also, do you see a big difference between the XT8 and XT10? <br /><br />How much additional weight did your EQ mount intoduce and is it still semi portable? I'll need to move my telescope about 20 feet from its storage location to get it out on the deck for outdoor, overhead viewing.<br /><br />Thanks again, your information has been great for me. <br /><br />Ryan
 
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bbrock

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Ryan<br /><br />The great advantage to the Dob is it is quick to set up and use. The XT8 is 41 lbs and the SkyView Pro 8 EQ is 64 lbs. This weight difference is probably of no significance. The truth is, the Dob would take about 5 minutes to set up and the SkyView about 15 minutes. <br />My personal opinion is that you would be most satisfied for the long run going with the SkyView. You just have more potential in amature astronomy. For one thing you will be able to tinker with and learn to use setting circles. You will also be able to study objects for long periods of time, change filters and eye pieces etc etc without having to chase targets around the sky, pusing the Dob. This is real nice. <br /><br />There is a difference between the XT8 and the SkyView 8. The XT8 is a longer focal length then the SkyView 8 by 200 mm. This means the SkyView has a faster focal ratio. ( f/5.9 vs f/4.9 ) Esentially this means the SkyView will have a brighter image then the Dob, and excellent for dim deep sky objects such as nebula and galaxies. But not much different. <br /><br />There would be an advantage of a 10" aperature vs an 8" aperature, obviously, due to the light grasp. However let me say, that you probably would not be going to the theoretical max magnification anyway. <br /><br /> A good rule of thumb ( realistically ) is that the everyday max usable magnification is equal to the aperature diameter in (mm). This would be for the 8" = 203 x and the 10" = 254x. The reason is that the sky seeing and transparancy rarely cooperate with astronomers. Most amature astronomers rarely go over 200x for this reason, regardless of aperature. So I think either would be good to work with, and the 8" less costly. <br /><br />Others may disagree, since sometimes you want to push the magnification to split double stars and walk around on the moon. Hell, go ahead and push it. You will still do OK, probably out to 400 - 450x. Just not as bright and sharp. <br /><br /> Clear
 
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ryang

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Thanks for your input Bill and crazyeddie. I do appreciate it. I'm still not sure what I'll go for yet, but I do have some great decision points. Now, I'm sure I'll find something that will keep me satified for many years... After that, onward and upward <img src="/images/icons/smile.gif" />
 
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ryang

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Hi,<br />I just thought I'd let you know I went with the XT10. I think as a starter, I should have good fun with it. If I get more serious I could look at an EQ mount for it or even just at a whole new scope. The XT10 really is affordable for what I got. Thanks for your input.<br /><br />Any suggestions on eyepieces, filters or best viewing practices with it? <br /><br />Ryan
 
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bbrock

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Ryan<br /><br />Excellent telescope. May I suggest you also order the EZ Finder II. My first purchase was the XT10 Intelliscope and after I quickly learned I didn't need the Intelliscope part, I still had trouble pointing to where I knew to look of objects. The EZ Finder II did the trick. <br /><br />The Dob is the easiest scope to use. You can set it up, point and view more objects in a fraction of the time of an EQ mount. You will find out however that the higher you go in power, the more time you spend moveing the scope. For deep sky objects this is no problem. The purpose of a telescope is to gather light. Usually deep sky objects require a lot of light gathering and low magnification. The moon can take all the magnification you want to throw at it. Many double/multiple stars require high magnification. Most globular clusters take low to moderate magnification ( 50x - 120x ). For example, M13 looks great at 120x. If you go to 240x you are no longer looking at M13, but into M13. Almost all open clusters take the lower magnifications ( 30x - 70x ). Planitary Nebula can usually take low to moderate magnification. Difuse Nebula requires as much light gathering and the lowest magnification you can manage. <br /><br />Your XT10 has a focal ratio of ~~ f/4.7. To achieve a maximum exit pupil of 7mm, your lowest power eye piece shoudl be ( 4.7 x 7 = 33mm). This will give you a lowest magnification of ( 1200mm/33mm = 36 x ). <br /><br />This minimum power eyepiece will be the brightest EP in you collection. This will be the EP you look at most galaxies with. I suggest you don't skimp on this one. If possible, try to get the widest field of view EP you can afford at around 30mm to 34 mm. <br /><br />It is nice to own a 2X Barlow. That is like doubling the number of EP's in your collection. I suggest you purchase a polarized moon filter. You will migrage into other filters as your interest grows. <br /><br />Your 10" scope will allow you to go much higher
 
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chrislee

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Hi All, my first post after doing some research. I'm buying for my better half who wants a telescope. I read http://www.scopereviews.com/list.html and thought I'd go ahead with the Orion XT8 Intelliscope w/ the computer as we're both beginners. I thought the computer thing would dial us right into stuff we had no idea where to look. But that software (see below) is pretty cool stuff.<br /><br />But now, after reading BBrocks suggestion for the Skyview Pro (really about same wt. and price point), I'm now not sure. I think I'd like the more adjustable tripod mount of the Skyview (I'm a photographer and I guess more familiar w. this type than the Dob mount). Plus I can appreciate an extra Fstop as well. But alot of people, and Ed Ting's site say to get the XT8 to begin with.<br /><br />I know we want to look at nebulas and colorful stuff (ok, I'm showing my lack of knowledge here so forgive me! <img src="/images/icons/smile.gif" /> I'm upto $687 shipped for the XT8 Intelliscope, computer and case delivered. The skyview is $550-600 for diff. drives..so about the same. I'm willing to spend more if the quality is worth it. I see alot of positive things also of the Meades LXD series..<br />this is $1k: http://www.digitecoptical.com/tel-meade-lxd75-6-refractor.htm..but f.8? kinda dark i bet and only a 6" lens. This is the other Meade about $1k also:<br />http://www.digitecoptical.com/tel-meade-lxd75-10-schmidt-newtonian.htm with a decent f4. <br /><br />I have NO idea really. Based on what we want to use it for, which one should I get? I hate asking that of people cause I know there's no simple answer. But for me, this is our first, and maybe last telescope. I'd rather have it be the best the first time aro
 
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bbrock

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Chrislee<br /><br />Your questions are tough to answer. There is no perfect telescope to do all things we want. This is probably why amature astronomers tend to collect different telescopes. <br /><br />The Dob is a great telescope mounting design because it is easy and quick to set up and use. The down side is there is no tracking. This isn't a problem for casual viewing at low to moderate magnification and/or with very wide field of view eye pieces. <br /><br />This past weekend I viewed Saturn at 3 AM. on two separate mornings. ( Terrible - Full Moon - Atmospheric Conditions really lousy ) but the Orion 10" reflector optics did a magnificent job. The first morning I didn't feel like fooling with the equatorial mount. I set the Dob up and could go up to 200x with no problem, counted 5 moons and looked at the cassini division. Then I tried 400x and had trouble getting anything in focus and track Saturn plus viewing time. So I went back to 200x. I decided the next morning to spend the time and effort to set up the EQ mount. I did the polar alignment and parked the telescope on Saturn at 400x. The atmosphere was lousy, now I had clouds moving through and focus was a constant problem. But Atlas EQ mount is great. I could work with the focus, go inside and get a cup of coffee, go out and view - change filters, change EP's and never fool with chasing Saturn through the sky by hand. The polar alignment was accurate. Saturn never left dead center for over an hour and a half. <br /><br />And so it goes. You cannot effectively use photography with a Dob. But Dob's have there place in this hobby. If I were viewing galaxies or large nebula's at low power, I would not have needed to set up the EQ mount. <br /><br />You will just need to search you feelings to decide which way to go. <br /><br />I suggest you consider the Starry Night Enthusiast. As far as binoculars go, I suggest 7 to 10 power with 50mm aperature. Do not get a cheap pair. The Leupold Wind Rive
 
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chrislee

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Hi Bill, and Thanks for the post! <br /><br />I woke up this am thinking simply, that the XT8 is just too big and bulky for me. I saw Dave Streets XT10 and his 80ED APO: http://home.satx.rr.com/despage/images/equipment/equipment.html<br /><br />That 10 is huge..and the 8 is only 4" shorter. Just doesn't seem very portable or easy to store in our small 900 sq ft. house lol Plus to pack up and bring out camping would be a chore.<br /><br />I'm thinking/ leaning towards spending more money on a SkyView™ Pro 100mm ED EQ Apo Refractor with the dual drive. Great optics, bright, 36"long, though still 40#s, and can be used w/ photography. Alot more money though lol Wierd they put this scope on a tripod though thats only rated for 20# when the scope is 40#s to begin with. But just getting the scope, and buying something like the Atlas™ Heavy-Duty Equatorial Mount brings the cost way high, but at least it's rated for 40#.<br /><br />Anyway, alot to think over.<br /><br />Thanks again Bill, and Ill def. look into the Enthusiast version!<br />Chris
 
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chrislee

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That is a good review Bill. Thanks. Looks promising for the price for sure. <br /><br />I read you can see the deepspace more w. higher magnifications, like the dobs. But for about the same price of that 100 APO Orion, there's these nice reflectors that seem managable:<br /><br /> Celestron NexStar 8i 8” f/10 go-to SCT with NexRemote software or a Meade 8" f/10 SC-8 AT LXD75 go-to equatorial model. I'm getting it narrowed down to a good few choices at different quality/price/option points.<br /><br />Thanks again,<br />Chris<br /><br />
 
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bbrock

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Chris<br /><br />I have to agree with crazyeddie. Always go with the largest aperature you can manage and afford. Astronomy is the business of gathering light. Resolution and Magnification follow in that order. Magnification is usually the least important. <br /><br />There are many deep sky objects that are best seen with low magnification and high light capture. Dim galaxies and large diffuse nebula you want very low magnification and high light capture. Most globular clusters require magnifications between 50x and 150x. <br />Objects that require high magnification would be planets, double/multiple stars, certain planitary nebula and of course the moon can take any magnification. The value of aperature is it makes the high magnification views much brighter and allows greater resolution. <br /><br />Now you know as much as we do. Best of luck.<br />Bill
 
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chrislee

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Not sure if I know 'which" one you're talking about Bill...which scope has the largest aperture? The Reflectors are almost all f10's. That's getting pretty small at least in photographers minds lol<br /><br />And the Orions are about f9 for the svp100APO vs. F8.4 for the SVP 120 Pro.<br /><br />So you're saying it'd be better for the f stops < f9?<br /><br />Thanks for all the help everyone! I could NOT have done this all by myself!!<br /><br />Chris
 
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chrislee

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Thanks guys! I'm getting it narrowed down. <br /><br />I found astromart, and I can get a Nexstar 8i xlt with 'go to', but w/out the NextRemote software for $1100 incl battery pack. I did want that software though, so I'm not sure about wanting it without that feature. But the go to allows tracking which is the most important thing I wanted. Good price w. all the accessories, but, it's an f10!<br /><br />**Is this the type you guys are recommending?**<br /><br />Celestron 8” f/5 C8N-GT Advanced Series go-to equatorial Has no coatings though and is just over 1k.Wish it had the coatings. And it's the only 8" reflector I could find that had a low fstop.<br />All the other Crestron and meades were f10s. ($1019)<br /><br />I did find some cheaper Orion reflectors: Atlas™ 8 EQ Reflector which is 1000mm reflector w/ a fstop of 4.9...but it weighs a whopping 95#s. (this is on sale for 900 vs. 1100)<br /><br />And lastly, the SkyView Pro 8 EQ Reflector which is also a 1000m/f4.9 ($600)<br /><br />Would this be a good buy???<br /><br />Otherwise, I'm looking at these otherr recommended spcopes; but as you can see, the fstops are pretty high. The choices are to either get the Skyview Pro 100mm APO for $1385 (f9) Just the APO is making me drool on this one LOL<br /><br />or just settle for the Skyview Pro 120mm EQ for $600 (f8.4) These tow also have at least the dual drive tracks but now go- totechnology.<br /><br />These are about my final choices. Thoughts?<br /><br />Thanks again and I wanted to let everyone know HOW much I appreciate the help!!<br />I never could've gathered and learned as much as I have recently w/out forums like this, and other people's webpages. The prices are really all around the same ballpark for me, so that's not an issue.<br /><br />The only neg. thing I can think of in a reflector is being able to also use if for close objects/plantes. Not sure how much optical degradation occurs using these downsize filters. Just a thought.<br /><br />Thanks again!<br /> Chris<b></b>
 
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chrislee

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First off..Thanks Crazyeddy for that post, it helped alot.<br /><br /><br /><A Schmidt-Cassegrain telescope is easy to use with cameras, and you can buy an accessory that reduces the focal ratio to F/6.3 for photography. /><br /><br />Oh, Is this how you're using f/10 Schmidt-Cassegrain scopes then CrazyEddy? You're using some kind of accessory to get more light in? Humm? Cause I sure as heck can find ANY 8" Schmidt-Cassegrain scopes w/ fstops smaller than f/10! So what's the name of that accessory?? (have a model or name for that??) <br /><br /><br />I did find a Schmidt-Cassegrain Celestron, the C8S-GT (XLT) 8” f/10 Advanced Series go-to SCT, with Starbright XLT multicoatings using a Schmidt-Cassegrain optical tube, and the Heavy duty CG-5A Advanced computerized German equatorial mount (that's what Anacortes website called it, Astronomics called it Celestron Advanced Series Computerized Equatorial Mount...both the same part bumber) the which is the same below even though diff name (same part number). This goes for $1514. That's about $100 more than the APO Orion. Which I know the APO would be nicer image, but can't match the disance. <br /><br />To piece meal another set, though with no Go To feature:<br /><br />1. Celestron Advanced Series Computerized Equatorial Mount $760 Cool has a motor drive too.<br />2. Celestron 8" Schmidt Cassegrain f/10 OTA with XLT coatings for $989<br />_____________________________<br />total: $1749<br /><br />Oh, this doesn't incl. any other options like that reducer you mentioned, cases, filters and other eyepieces and the battery. So this setup is getting up there in the end.<br /><br />Or, I can get that used 8i for $1100, and upgrade the tripod to that $760 Equitorial mount now....for $1860..or wait a bit and upgrade later. Th used 8i comes with: "a bonus Bobs Knobs (make's collimation a snap), the Celestron 12V Powertank (cables included), Orion Flexi-shield dew shield, and "The Nexstar Users Guide" book, which is very h
 
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chrislee

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That is a good sale price there TFWThom.<br /><br />1400, plus 50 for the a/c cord and I realized i'd need something like a Nagler 11mmT6 for a nice 200x mag....total of $1700. Boy this stuff adds up fast no? <img src="/images/icons/smile.gif" /><br /><br />Chris
 
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bbrock

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Chris<br /><br />Welcome to the world of amature astronomy. You pick up on this stuff pretty quick. You have also learned that there probably isn't one scope to do it all. So you acquire the equipment that suits your basic intrests and evolve from there. I suggest you start out simple and not so expensive, and learn your way around the sky. If you still have a burning passion six months from now, then you will have a greater foundation plus much more experience to go from there. <br /><br />Unfortuantely, we do tend to collect more then one telescope. It's a good thing the eye pieces are made in standard sizes. <br /><br />Bill
 
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tfwthom

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Yes Chris it adds up the longer you'ra in the hobby. I guess I have about $30k easy in equipment. The LX90 ends up being the least expensive scope I own now. <br /><br />Nice thing is a lot of the eyepieces work with the other scopes (FS128 TV85) <br /><br />Personally I don't like Dobs but that's just me. There are enough around so if I get apeture fever I just look through one of the 20"+ Dobs and I'm cured. <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>
 
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tfwthom

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After thought<br /><br />On eyepieces<br /><br />If you are getting an 8" SCT you are going to love a 32mm TeleVue Possl and a 20mm TeleVue Possl. Add a 2.5x TeleVue Powermate and you will have enough eyepieces to last awhile. Most 8" SCT's come with a 26mm or 28mm so you'll have<br /><br />32mm = 63x w/barlow 126x w/2.5 158x<br />28mm = 75x w/barlow 150x w/2.5 188x<br />20mm = 100x w/barlow 200x w/2.5 250x and you are maxed out here<br /><br />8" SCT drawbacks....I don't like them on open clusters or the Vail thats why I got the TV85. On Mars it's hard to resolve detail thats why the FS128. Otherwise they are a great general viewing scope. <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>
 
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chrislee

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Morning! And TFW, My O MY!!! Aren't those two telescopes Beautiful! What works of art nearly! Really. I like those prices of those ep's better too you just mentioned!<br /><br />Bill, still wondering the same here this am. But I found an article by Ed Moreno last night on light pollution:<br />http://www.astromart.com/articles/article.asp?article_id=149<br /><br />he suggested a reflector as it was most usable in the city comp. to 4 refractors. Interesting.<br /><br />But yeah, I totally understand and for the most part agree fully with you. I'd really like to take that advice and get the SkyView Pro 120mm EQ Refractor (why didn't they at least use ED glass on this one anyway?) for $750 incl a case and a simple 2-3x barlow shorty plus. But I'm pretty sure the LX90 is easier to use and I can see alot more with it as well. I Definetely understand why most have two kinds now! lol<br /><br />Chris<br /><br />btw? whats polar aligning? and do ALL telescopes need to have a laser collimate them?<br /><br /><br />
 
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