Which is the best between these 2 telescopes?

2844az · Dec 16, 2007

I am trying to choose between the Orion SkyView 180 EQ Mak-Cass, non-go to. Which yields a magnification of 104 x with a 26 mm eye piece. It has 2,700mm focal length with (f/15). Price 1549.00. The other choice is the Orion SkyView Pro 8 XLT Schmidt-Cassegrain (non-go to). It yields 78x with 26 mm eyepiece and has 2032mm (f/10). Price 1449.00. The 9.25 model yields 90X. Both use Sirius plossi eyepieces. I want the best telescope for the money. I am not sure about the f/15 and f/10, which is the best? I would appreciate your comments. Thanks, Gary

adrenalynn · Dec 16, 2007

Hi Gary! Welcome to SDC! Great scopes you're looking at, in a great budget. Would you tell us a bit about what you're looking to do with the scope? What you're hoping to accomplish? The Pro 8 XLT SC scope is actually a mid-end Celestron product in the optics-department. The XLT coatings by Celestron are pretty much the undenied champs in that price range and on up a LOT. The magnification is rarely important unless you're doing serious planetary work. That said - you're looking at one eyepiece's magnification and not the maximum useful magnification of the scope, and its "maximum reach" based on aperture. 180mm is about 7 inches. The Pro 8 is 8 inches. The 9.25 is a drool-worthy scope. One thing to consider is how dark your skies are. Under a lot of light pollution, a quality 8" scope with part of the cost difference between the 9.25 and it invested into a light-pollution filter and top quality eyepieces will yield better results. But when you get it out to dark sky - the 9.25 will walk all over the 8". Consider the weight if you'll be moving it around a lot. The slower scopes (like that f/15) are more tolerant of "cheap" eyepieces, but in your price range, you shouldn't even be thinking that way, IMHO. I'm never been fond of the Mak-Cass designs. I find them more difficult to pull a really tight focus. As an astrophotographer, that's crucial to me. I'd take a 5" with great optics and good SC design over a 7" that I can't pull focus on. For visual, it may not be as critical. They both COME with Sirius Plossl eyepieces. They'll both USE whatever you put in them. The Sirius Plossls aren't bad. I use them in my NexStar 5. But with a larger scope with XLT optics, you're really going to want to upgrade to fully multicoated optics. (The Sirius are multicoated, not full multicoated. I'll explain the difference if you like...) I'd choose the 9.25 XLT if price weren' <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

MeteorWayne · Dec 16, 2007

We naked eye meteor observers bow to your extreme knowledge. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

adrenalynn · Dec 16, 2007

Thanks for the vote of confidence. <img src="/images/icons/laugh.gif" /> I'm sure CrazyEddie will want to jump in on this one too. Not every day we have people coming in looking to spend somewhere around two grand for a scope. It's usually $150. <img src="/images/icons/wink.gif" /> I did want to add, however, that the Mak-Cass might be a consideration if you wanted to devote your entire passion to the planets out past Jupiter. The Mak-Cass *might* be a better visual performer for Neptune and Uranus. Under perfect skies. It would probably yield more natural detail under perfect skies for those two planets photographically too, if you can pull focus. But I don't believe it has XLT coatings. And the advantages to a naturally higher power/larger exit pupil that you'd get off the Mak is going to go away really quickly if you get stray light bouncing around lower quality coatings. You might also get nicer views of the brighter clusters too, with lower power eyepieces. Because you're using lower power EP, the light transmitted will be similar between the 7 and the 8" scopes with all else equal But the Mak doesn't have XLT coatings (just checked) - the SC does. Bottom line for me: The Mak would be a good specialty scope, or second/third scope for specialty work. I'm not a huge planet-fanatic. Even my 5" NexStar SC will resolve the Cassini Division on Saturn's rings (even on a fairly poor night), the polar caps on Mars (on a good to very good night), and deliver color on Jupiter with a good number of bands (up to 6-8 bands - 12 bands for the 8", under fairly good skies on a good to very good night). My 8" SC could see several of the impact sites from the comet back in Shoemaker/Levy 9 days. How much more planetary do I really need? <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

2844az · Dec 17, 2007

Let me first say, I am very thankful for this discussion board. And for the kindness of those who are willing to help answer some of my questions. I learned a long time ago that you have to research an item very carefully before you purchase it. I realize no one telescope does everything. I wanted to view planets and see some of their details and look at nebulas and galaxies. I have looked into the night sky for about 30 years. I named my first son Orion. My enthusiasm started as a child in Oct. 1965, when I saw the Ikeya-Seki comet. It lit of the sky in the East and was visible in the daytime. I think it was more beautiful than McNaught. I cannot find pictures of Ikeya-Seki on the East coast. The Starry Night programs are such wonderful celestial tutors that my quest to search the stars again has been rekindle. Now I can be sure of what I am looking at. At age 49 my eyes are not what they use to be. So I am trying to get a higher aperture relief eyepieces and also greater power. I am not sure of the f/10 or f/15 aperture meaning. If it is like a camera the f/15 would be a sharper image, but I think you might have to strain harder to see it, but I am not sure. What would you recommend on the eyepieces? I like the 25-26mm., but I need to step down one more perhaps 17-18mm. I want to be able to see the image clearly. On my telescopes the eye pieces at 7.5-12mm, often give a distorted image. Thanks again for your earlier response. Gary

heyscottie · Dec 17, 2007

With respect to the f/ ratio of a telescope, you can't look at it exactly the same way you do photography. In photography, going to a higher f/ ratio does widen your depth of focus, due to the pinpoint camera effect. This does still hold in telescopes, but remember that in a telescope, all items you look at can basically be condidered to be at the same distance -- infinity. The f number of a telescope is calculated by dividing its aperture in millimeters by its focal length in millimeters. Other posters have claimed that higher f numbers are better for cheaper eyepieces, which is correct. This is because a telescope like this gives a narrower light cone to the eyepiece, meaning the eyepiece only has to work well for a narrower portion of its lens groups. But in general, the most important number to look at when buying a telescope is aperture. Above all, aperture is king. Aperture decides how much light you can gather, and therefore how faint of objects you can see. Aperture determines, because of diffraction, what your maximum useful magnification can be. You can add lots of things to a telescope after buying it -- more eyepieces, a better mount, filters, goto packages, finderscopes, whatever -- but you can't add aperture. Probably the next most important thing, depending on what you want to do with it, is the mount. A shaky mount makes a shaky image in the eyepiece. Mounts rarely get attention, but they are very important. If I had a choice, I would get a Celestron 9.25" XLT SC scope. And I wouldn't get goto. And I would get the beefiest mount I could for my budget. Another way to go, and for much less money, is a large Dobsonian telescope from Orion or Obsession. You can get a LOT more aperture if you want to, while sacrificing equitorial tracking... Scott

adrenalynn · Dec 17, 2007

Seems we're all on the same page here! The only place I might differ a little with CE is in visual difference betwixt the 8" and the 9.25". From personal experience with both those Celestrons, the 9.25" will define tight globs better, making them "crisper" or "crunchier". (Assuming good dark skies). Also, the chances of scoring a dark nebula (like the Horsehead as a prime, comparatively bright, example) are substantially better in the "same" 9.25 vs the 8. Also, this is a major purchase. If you decide you want GoTo or to do photography, or to add an RA [and] Dec motor later - it's nice knowing you had the scope you really wanted. That said, and as I think I mentioned earlier (and Crazy Eddie mentioned), if your budget is limited to the point that you're considering the 9.25 and the stock eyepiece - get the 8 and good eyepiece(s). <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

2844az · Dec 18, 2007

I appreciate everyoneâ€™s input on this subject. I think they way to go is with the Pro 8 XLT SC scope. I have astronomy magazines from 10 years ago that always put the SC scopes as one of the best. And the input here points to the SC. Now the accessories, what can I do to tweak it up! What size eyepieces would be beneficial or practical? And what brand name of eyepieces would do a better job than the Sirius Plossl? And one other thing, Is there a Barlow lens that is actually worth its salt? Thanks so much, Gary.

2844az · Dec 19, 2007

Adrenalynn you mentioned, "I'd personally get the 8" on the GEM mount and add an RA motor to it. With careful setup, it will deliver multi-minute exposure for astrophotography and still come in less than the 9.25." I assume the SkyView Pro mount is not ideal? What would you recommend to replace it? And what RA motor drive would work well for astrophotography? One more question. Can you buy these telescopes in units and build them the way you want to? Crazyeddie suggested better eyepieces also and a better premium diagonal. From the wisdom of you generous men, I gather it would be nice to buy the parts individually and then assemble the telescope. Can you do that? Thanks again, Gary

adrenalynn · Dec 19, 2007

What about us women? <img src="/images/icons/smile.gif" /> Seriously though - give Orion a call and tell them you'd like to buy the OTA (Optical Tube Assembly) - it's not in their catalog, but I've done it in their store before. The SkyView Pro should probably work ok with the 8". The Atlas would rock. The CG5-GT should also rock, although I'm not familiar with it for astrophotography. I'm contemplating buying one right now for my little N5 scope. The Atlas is pretty pricey. The Skyview Pro and the CG5-GT are much more reasonable. And the CG5-GT adds goto, and also has an autoguider port. Ideally, you'd want PEC (periodic error correction) but that tends to add a lot of cost. The Meade LXD75 and maybe the LXD55 offer PEC. I'm still investigating that myself. Yes, definitely building a scope from the component level will give you a better end result, imho. The manufacturer is target pricepoints, so they skimp in some places and go higher in others. If you want a pricepoint somewhere in the middle of the other pricepoints, then YOU get to choose where to spend and where to save. <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

2844az · Dec 19, 2007

I humbly apologize lady Adrenalynn. Thank you for correcting me. And thanks for the info. Do you have a preference on the RA motor drive systems? I have heard numerous complaints about various RA drive systems when used in astrophotography.

adrenalynn · Dec 19, 2007

Oh - no worries! I'm actually not at all touchy about it. That's why I added the emoticon. At least, I think I added one... <img src="/images/icons/wink.gif" /> You know, I've been researching inexpensive drives for months. My observatory system is really expensive. (five-figures expensive). The conclusion I've come to is that anything less than $2k is sub-optimal for imaging. That said, what many of the gear-heads consider sub-optimal would crush my current setup. I'm not wanting to spend the money on the Orion Atlas - but I'm wanting the Atlas. I'm not wanting to like the Meade LXD75, but it does have PEC, is rated for more weight, and it's going for sub-$700 street price, it's awfully tempting. I'm wanting to want the Celestron CG-5GT - but allegedly it doesn't have PEC. Both have autoguider sockets. The CG-5GT costs about a hundred dollars more than the LXD75, street price. The SkyView Pro is somewhat out of the running for the weight rating. Although the scope I want to ride on it is way under the weighted rate, for astrophotography you can never have enough mount. The more under the rated weight, the more stable and the better the tracking, generally. The tube I want to put on it is 7.4lbs, the camera is another 2.5lbs, all the rest of the rot adds up to about 2lbs. Add a good illuminated finder scope for another 2lbs. 14lbs total. The skyview pro supports 20lbs. The Atlas supports 40lbs. The skyview doesn't appear to have PEC, the Atlas does. The Meade LXD75 is rated at 40lbs "for visual use" - which says to me they're being more honest. The CG5-GT claims 45lbs. Street on the LXD75 is about $600 Street on the CG-5GT is about $700 Street on the SkyView Pro about $800 Street on the Atlas is about $1500 From there we get into the "real" astrophotography mounts. Losmandy, Tak, Borg, Meade LXD 750, ... And pricing can run from $2100 up to "how much is your house worth again?" <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

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Which is the best between these 2 telescopes?

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