Choices..........aargh !

BillW · Guest

I've done by trawling of the net and reading as to getting a scope. To date I've used binoculars and occasionally a 77mm 32x spotting scope. Now looking for a proper astro product with the following priorities:
Moon / planets
Terrestrial (when the 77mm is not about)
Other astro
Terrestrial photo
Astro photo will be casual at most.
Based on that I seem to be looking at 5 or 6 inch cats, and I like the goto idea at least some of the time.
An unknown is any interest in deep sky, but I accept if I get too keen it will need another scope entirely. It would be good to have some capability though.

Of the obvious contenders (Meade's 125, Cel's Nexstar5 and 6):

What do I need to consider to help choose, if this is even a good choice so far ?

Any others worthy of consideration around the same or lower price ?

Is the extra inch aperture of the Cel 6 going to make a lot of odds or would the $ saved be better used on higher grade eyepieces for the Cel 5 ?

Will the tube on these come off as a tube alone for terrestrial spotting use on a normal tripod easily (or is this not a good idea ?)

Is the T adaptor fully screw in and solid ? I don't fancy my DSLR held on a 1¼" mount and a grubscrew

Your thoughts please, regards

Bill

Ryan_W · Site Admin Joined: 16 Jun 2003 Posts: 276

Hi Bill,

All three of these are good choices. The 5" models are a Maksutov design which will give you a flatter field of view will less chromatic abberation. The 6" will obviously bring in more light. If most of your viewing will be planetary, then you will not need the extra inch of aperture. If you will be doing more deep sky, the extra inch will be beneficial. With astrophotography, the extra inch will allow you to have shorter exposures.

The camera mounts for the Meade is a solid thread on design, and I'm pretty sure the one for the Celestron is, too. I presonally like the mount of the ETX 125 better, since it is a double fork mount with a built in wedge to use it in equatorial mode for photography.

Both series allow you to turn off the motors so you can use them in their mounts for terrestrial viewing.
_________________
Best Regards,

Ryan W.

Forum: http://www.opticsplanet.com/msgboard
Blog: http://blog.opticsplanet.com/
Store: http://www.opticsplanet.net/

Phone: 847-513-6201
Fax: 847-919-3003

fraunhofer · Posted: Wed Apr 23, 2008 8:03 pm Post subject: 6"F/15 refractor?

Why a 6-inch F/15 Refractor? From my years of experience as an astronomer who has used a variety of telescopes of different types along with using very rare large apertures of 8-12 inches. I have found the 6 inch F/15 refracting telescope is the optimum design for lunar, planetary, and solar observing. The telescope’s size makes it the best instrument in my opinion for advanced observers to use and simple enough for elementary observers to use for their viewing. An observer can master the telescope system with relatively few instructions, and yet the system is large enough to provide optimum viewing in city astmospheric conditions. Furthermore for more advanced observing the 6" F/15 refractor with it’s accessories provides opportunities for photographic and spectroscopic work as well. Observatories and educational institutions usually have found the 6-inch F/15 refractor to be the finest instrument for lunar, planetary, and solar observing. For those wanting to build a 6" F/15 refracting telescope system for their observing should obtain a copy of "Telescope Making44" and read the article entitled "Constructing a Large Brass Refractor" by Larry Myers. Telescope Making was a publication of Kalmbach Publishing Company (Astronomy Magazine)
_________________
L.Knowlen, GHLO

Jne_K · Site Admin Joined: 24 Sep 2003 Posts: 5018

Hi

Can't argue the merits of the classic 6" f/15, but, like any design, there are trade-offs. Great choice down through the years, with minimal chrmatic abberation and enough aperture to get serious. These days, though, Maks and SCTs are providing the same focal lengths in much shorter tubes and eliminate chromatic abberation, completely. Guess that's one reason the 6" f/15 is fading into extinction - tough to find one, anymore. Truly a shame, if you've never had a chance to oberve with one. For you do-it-yourself types, check out the reference.

Good post.
_________________
Thanks for posting with us
Joanie K - Your personal optics expert

Forum: http://www.opticsplanet.com/msgboard
Blog: http://blog.opticsplanet.com/
Store: http://www.opticsplanet.net/

Phone: 847-513-6201
Fax: 847-919-3003

fraunhofer · Posted: Thu Apr 24, 2008 12:24 pm Post subject: 6"F/15

Hey there is still D&G along with Astro Physc.. Even though there systems may be F/8 - F/12 they along with Meades ED system are very fine. Sorry I shold have put that in before.
_________________
L.Knowlen, GHLO

Guest · Posted: Fri Apr 25, 2008 4:51 pm Post subject:

Thanks for the input everyone. Two things weighed against a refractor; the terrestrial use includes a mile or two walking through town, so compact is a plus as is not too conspicuous, and even the 77mm/x32 one I mentioned is a pain at high elevation use as you get so much tripod height catching the breeze. That said I have seen that Saturn has rings and the occasional sign of banding on Jupiter with it. Such a shame they only do an x32 eyepiece for those optics.

Unless I'm misunderstanding, I don't think the photo exposure time will change as both the Cel's are f/10. The ETX at f/15 is a slight minus on it though.

One other point I have found out, is that the shorter focal lengths in the Meade 4000 eyepiece series are not recommended for those wearing spectacles, shame they hide the eye relief data on their eyepieces.

regards
Bill

PS I might answer the odd thermal imager question here (thats my dayjob)