Your opinion on 5" Mak selection?
Posted 30 May 2004 - 05:22 AM
Posted 30 May 2004 - 05:38 AM
The scope comes in different packages. My pacage was with a 2" diagonal, but no finder scope (but it did have a pair of three point finder rings for a 50mm finder scope - go figure).
Anyway, it is a nice scope and certainly worth including in your list.
Posted 30 May 2004 - 07:37 AM
If I had LOTS of money I would buy the Intes Micro MC. Meade ETX has good reputation on excellent optics, so their ETX125 spotting scope is also a good choice.
As regards the low cost section the Orion Starmax 127 with a GEM costs the same as the bare Meade ETX 125 OTA. I have had both telescopes (unfortunately not at the same time) and I prefered that there were NO image shift in the Orion MC. It has excellent optics as well.
Celestron C130 is a new competitor I don't know much about it. It has very long focal length which yields small FOV, but the 8x50 finder is a big plus.
All in all, if I had lots of money to spend I'd choose an Intes MC. If I were on a small budget, i'd go with the Orion Starmax 127.
Posted 30 May 2004 - 06:01 PM
After being initially impressed with the Meade ETX range 'on paper', I went off them because they strike me as being rather flimsy and fussy 'in the flesh'. Lots of plastic and flip mirror systems, etc, strike me as potentially unreliable for long-term field use.
The Orion Starmax 127 comes with an EQ3 mount as standard. If you already have a mount, the model to look for is the Apex 127. This is £389 in the UK, which is pretty expensive along with all the Orion USA range (£535 for Starmax). These scopes are made by Synta in China, who also market them under their own Sky-Watcher badge. Unless you particularly like the red paintwork of the Orion badged version, I'd look out for the Sky-Watcher Skymax 127 (might also be known as 'Viewmax'). This is available in the UK for as little as £310 for the OTA or £410 on the EQ3/2 mount.
I'm very pleased with my Skymax 127, and have discussed it at some length in a thread here called "Sky-Watcher ViewMax 127mm EQ-3 Mak ???"
With all these scopes, you're only going to get an extra inch of aperture over your current Mak. They're still going to be pretty hopeless on deep-sky, and you might be surprised at how little extra they offer on the Moon and planets (similar expressions have been noted between ETX-90 and ETX-125 comparisons), assuming your Nexstar is a good example.
The Russian scopes tend to be more consistently better than the Chinese efforts in terms of optical quality. In that sense the Intes-Micro mentioned above would probably offer a significant performance leap from your Nexstar 4. But for that money you might want to consider an Intes MK67, which is a six inch Mak. This would offer an obvious benefit from a four inch. The MK67 might still be on offer at Bray Astro:
If I hadn't also needed a mount and stuff, I would have pushed the boat out and got one these. Note, though, that the scope has about 100m close focus - not really ideal for terrestrial use.
Posted 30 May 2004 - 07:31 PM
Regarding aperture size, I'm not looking for a huge improvement over the NS4GT just yet, I've still got a lot to see and learn with a small scope before I get aperture hungry! I see a decent 5" Mak as being as good as some of the best 4" refractors and clearly better than an f/10 4.5" Newtonian. I've had the opportunity to use some larger refractors recently and was easily put off by the fringes and false colour, and I have not been impressed by the quality of Newts I've seen up to 6.25" because of coma and collimation. Both types are also rather cumbersome and susceptible to wind. I've also looked through a some SCTs in recent months and was alarmed at how soft the images were compared to my NexStar 4. All in all, most of the scopes that impressed me were Maks. I favour the NexStar 4 over most refractors, Newts and SCTs I've seen (except for one 20" truss-built dob that I certainly can't afford) except for the fact that it can't be used with a camera attached to prime focus at angles near the zenith, a failing it shares with most small fork-mounted scopes and some larger ones, and the OTA can't readily be detached for mounting on the EQ3-2 GEM I already have. The three I listed would be a 'minor upgrade' in terms of optics but a big leap in practicality.
Longer focal length means a slower scope and smaller FOV but has the advantage for me of using longer focal lenght EPs for a given image scale, which are better when you wear spectacles and your eyes' range of focus is reducing (the joys of middle age). That's one reason I included the Meade and Celestron. The other is their spotting scope capabilities for daytime photography.
The Celestron is included because it may be available from the Astronomy Shop in Dublin even though I haven't been able to find a review, but if it is similar to the Konus that's no bad thing. The threads here reported problems with just about everything except the OTA, which is all I want and all Celestron offer. It will fail selection though if the quote doesn't meet my estimate of what a fair price should be.
The others I can import myself without difficulty from a good Internet dealer because there are no approved distributors listed for Ireland, so I don't have to pay European markups, but a Celestron I can only buy in Dublin. Imports from Europe I will try to avoid because European scope markups seem to be running at 50-100%, whereas US sites sell higher volumes at lower markups, which not only offsets the shipping costs but makes for real savings for as long as the Euro is worth more than the dollar (US companies should take more advantage of this).
Does anyone know any good review sites that cover both astronomy and terrestrial viewing and may cover these scopes?
Posted 30 May 2004 - 08:31 PM
The best (i.e. apochromatic) 4 inch refractors will thrash any production 5 inch Mak. Although the Mak will have a bit more resolution due to the extra aperture, there will be a much bigger useful benefit from a 4 inch apo refractor in terms of contrast. That's just an unfortunate fact of life regarding the large central obstruction of the Maks. Large central obstruction = mutilation of contrast; especially low level contrast. Light gathering power is about equal between the two types.
I see a decent 5" Mak as being as good as some of the best 4" refractors...
All else being equal, I'd much rather have a 4 inch apo than my 127mm Mak (even a high quality Russian size equivalent). But all else isn't equal. I can't afford a 4 inch apo now, and my Sky-Watcher is a he11 of a lot more portable than my old Vixen flourite was.
On the spotting scope potential, the Synta 127 focuses quite close visually - about a single carriageway road width. It is certainly useable for bird watching in a sizable garden. I don't know about the scope's photographic potential - it's not an aspect that interests me I'm afraid.
Posted 30 May 2004 - 09:22 PM
Posted 30 May 2004 - 10:14 PM
Posted 31 May 2004 - 02:38 AM
I hadn't considered the C5, it's lighter, shorter and has StarBright coatings (the C130 is multicoated), and you've compared it favourably with the ETX (which is more expensive), but it's almost twice the price of a C130. Things are definitely tending toward the Starmax or equivalent.
Posted 31 May 2004 - 07:45 AM
Given the findings, and the comparison of costs of a new C5 vs a new Synta 127, it's a no-brainer win for the latter (unless the use of 2 inch eyepieces is essential).
Posted 31 May 2004 - 10:06 AM
Posted 31 May 2004 - 01:13 PM
By the way guys I really appreciate your help in brainstorming this.
Posted 31 May 2004 - 02:18 PM
Posted 31 May 2004 - 03:16 PM
If i understand correctly, the NextStar 4 is a MAK too. If you want "grab 'n go" why go for the bigger 5" size? I have the Orion 127mm MAK on the 3-2EQ, altough it is portable, i do not consider it "grab 'n go". Back-packing or hicking with it(or taking it with you as airplain luggage) seems not such a good idea to me. Especially not when you plan to use it in combination with an EQ3-2.
I really do not want to make your decission more difficult but have you considered selling the Nextstar 4 and buying a 127mm APEX AND a 90mm APEX in return? In that way you the slightly larger aperture over the 4" nextstar for use with your EQ3-2 (don't forget to get the dovetail plate) AND you get a real "grab 'n go" MAC; the 90 mm is very small, has razor sharp optics and WILL be stable on any decent alt-az mount. I used to have the 90mm EQ version meself for a short while; they're fine for this kind of use.
Posted 31 May 2004 - 03:22 PM
Posted 31 May 2004 - 05:12 PM
Thinking along these same lines, the C5 weighs in at around 6 pounds, which is smack between the Apex 90 and 127, and with both a focal reducer and an Ultima 2 Barlow would give f/6.3, f/10 and f/20 on the same photo tripod or AltAz that I would choose for the other two. Maybe I wouldn't need the Ranger and could start saving for a backyard light cannon
When I say grab & go I mean 'go in the boot (trunk)', but none of these OTAs would be a particular strain together with a photo tripod. I also want to get to a slightly bigger aperture because I don't have the budget right now for a large Mak or SCT - Newtonians have too much windage for my back yard.
Posted 31 May 2004 - 05:58 PM
The baffle tube diameter of the C-5 OTA is 1.5", hardly large enough to take advantage of 2" accessories.
The baffle diameter for the Intes Macro is also less than 2", but it can use two inch eyepieces. Light does not travel through a telescope in parallel lines. The baffle on an 500mm f/8 reflex lens is about 15mm, but it can illuminate an entire 35mm frame.
John, I have no idea if the C5 can use 2" eyepieces, but I would contact Celestron or get in touch with a C5 owner.
Posted 31 May 2004 - 07:01 PM
Posted 31 May 2004 - 09:39 PM
Yes, you can put a Televue 2" adapter and diagonal on a C5, but what for? I have a C5 OTA and use a 1.25" Lumicon enhanced mirror diagonal. Works great. I get a little vignetting with a 32mm eyepiece but it's not objectionable.
Posted 01 June 2004 - 01:28 AM
I get your meaning of "grab 'n go", i also understand that a 90mm MAK and the Ranger are a bit overkill, although you would get better results in the high f-range with the MAK.
What I don't understand is why you really want to get a 5"MAK when you already have a 4" MAK. The difference is really minor when looking through them. Portability does not seem a problem with the 4" to me.
Unless your money is burning in your pocket and you are eager for a new scope (which i CAN understand ) i would wait and get a slightly bigger aperture scope; a 7" MAK or 8" SCT if size is an issue, because of the 4" you already own.
Posted 01 June 2004 - 07:01 AM
Ireland is a very cloud-prone country, and also has perpetual astronomical twilight from mid-May to the end of July each year. I want to have some fun doing scenic photography as a second hobby that makes use of my equipment rather than just being constantly frustrated by cloudy skies. The past season's campaign was dismal.
The NexStar 4 is not practical as a back-packable spotting scope/telephoto lens because the OTA can't be dismounted from the heavy GOTO base and mounted on a photo tripod but some of the ones in my original list and the C5 are. The Orion Apex 127 is on the edge of that category, but still in with a chance. Of those discussed the C5 is probably the best all-round in terms of weight, size, aperture and range of accessories and availability of post-warranty technical support in Ireland. It's cost is a little more than I originally envisaged, but the StarBright coatings would definitely make it a much better astro scope than the Celestron C130 for instance. My second choice is the Orion, but that is first and foremost a good astro scope, and it's spotting scope/photographic accessories are not as diverse as those of the C5. Both will fit on the EQ3-2 GEM as well as other tripods I have, and I can easily make adaptor plates for one of them if needed.
Probably the most important feature of the new purchase will be that it, the Ranger, my camera and necessary accessories will fit in a backpack, with a tripod where the bedroll/tent would normally hang, for hiking on foot to scenic vantage points. Not your average 'grab & go', but close enough!
Posted 01 June 2004 - 02:19 PM
John, there's an MN51 for sale on ukastroads.co.uk for sale for less than 400£. Are you going to buy it or do I have to do it myself to keep the Free World going?
Posted 01 June 2004 - 03:25 PM
But VMT nevertheless Matt.
Posted 14 June 2004 - 10:28 AM
Thanks for all your input
Posted 14 June 2004 - 10:44 AM
Congrats on the new purchase. I have heard good things about hte C-5's. Let us know how you like it.