Posts Made By: Matt Luttinen

Hello everybody,

Here is my 14.25" f7 Newt. I have posted a few pictures before but this is a "latest version" photo.

Matt

Hello everybody;

I am seeking testimonials, good/bad, on the reletively new Celestron GOTO CG-5 mount and 10" f4.7 Newtonian OTA. I have browsed the Celestron_AS group and would like to hear more. I want to buy a Newtonian scope that is quick to load/transport/assemble yet gives fairly accurate tracking. I am not in the market for a Dob and platform.

The tone of the egroup is that the GOTO on the CG-5 is problematic/buggy and that the 10" is pushing the limit of the mount (probably right about that) but I think that in many groups you read about the problems more than the successes. It's just the nature of these groups, IMHO.

Any info on the fit/finish, mechanical quality, etc, would be mucho appreciated.

I would settle for a little shaking (~2-3 sec damping time) if GOTO & tracking is accurate.

I am also open to options, particulary of any 10" scope, new or used, (got one you want to sell?) on a driven EQ mount (both axes) that is DSC ready. I don't want too much do I? heh. GOTO is not imperitive. I own an Argo Navis, so push-to with tracking would work for me.

Oh yeah, and I want it to be fairly solid. For less than $1200.

TYIA

Matt

Hello everybody,

I have the opportunity to purchase a Meade RG mount. It has a stock AC RA drive, no dec drive (needs the dec arm), and what looks like a home-brewed/prototype drive corrector. I would want to get all the necessary stuff to get it fully driven. What is the best way to go? JMI motodec? Mototrak III-IV-V? (could be hard to find). What kind of drive accuracy could I expect with a Mototrak? Also, what is the REAL capacity of this mount? I want to hang a 45lb 12.5" f5.6 Newt on it. I have seen 16" OTAs on this mount and it looks like an exercise in insanity to me!

With a $500 initial investment, could another $600 make it a sturdy sub-5 arcsec error mount (with the Mototrak's PEC)?

Or is there new technology that would do the same in the $1000-1200 range?

Am I crazy to try making the RG an imaging mount?

I am counting on all you old equipment honchos to give me the honest, unvarnished truth . . .

TYIA,

Matt
Glendale, AZ

I happily go "space truckin" with my Synta 120mm f8 refractor. It is about as good as a doublet achro can get without spending big $.

PS: DP ruled! Richie Blackmore's playing still sounds amazing after all these years . . .

I did just this last fall using a 120mm f8.3 Synta refractor. The result was extremely close. I found the Nagler to have slightly more contrast, while the Meade UWA was slightly sharper--it snapped to focus a *little* better than the Nagler. I also concluded that the Meade gave slightly tighter Airy disks when in focus. I ended up selling the Nagler and keeping the Meade. Your results may be different . . .

This kind of comparo is really a do-it-yourself thing. Everyone has different eyes and equipment (duh) so my advice would be to purchase the Nagler, compare them, and if you dont see enough difference, return the TeleVue.

I have moved up to a 14.25" f7 Newt, so I wonder if the results would be the same if I did the test again . . .

BTW, my EP collection is half Meade UWA (14, 8.8) and Nagler (20 T2, 26 T5) so you might find that there is a space in your EP box for both too . . .

Regards,

Matt

I have a 4.25" f10 Palomar Jr., which is the metal white-tubed model seen in the picture on the Telescope Bluebook Edmund's page (follow David's link above). I understand they were made during the 60s and 70s. If the Bluebook is correct, your scope is probably from the late 70s-early 80s.
Mine is from the early 70s (I think).

I managed to assemble a complete Palomar Jr "kit," including the blue "showercap" tube-end covers, 1/2" and 1" (!) fl EPs and variable (!) barlow, and Edmund's excellent guidebook "How To Use Your Astronomical Telescope" with a copyright date of 1959!

My recent evaluation of the Palomar Jr is that it's main weakness lies in the original EPs, which were marginal at best. The 1" Kellner is OK for low power, albeit with rather nasty CA, while the 1/2" Ramsden is useless.

Congrats on your purchase, she's a beauty alright, if not quite as pretty as the Palomar Jr . . .

I have included a picture for comparison.

Regards,

Matt

David,

Actually the jump from 16" to 33" is huge in every way. You go from ~201 sq inches to ~855 sq inches, a 425% increase. A 33" scope of that design will weight a bunch, maybe 300+ lb or even more. At the zenith, your head is ~13 ft off the ground, not a trivial distance. Just moving the ladder would be easier with two people. BUT, the views would be stupendous and ruin you for smaller scopes. Some M objects might even show a little color (M42 for sure), and mag 15 galaxies would be easy. But scopes like this are *work* to move and use. I own a 14.25" F7 Newtonian, and it is a 1 hour job to set it up. I wonder how easy (er, hard) it is to set up that monster . . .

Ah, but size does matter!

Regards,

Matt

Craig,

I would trust Newt's calculation. Without being too specific, I talked to a noteworthy Dob manufacturer last year and he said that the calcs in K & B's book are too aggressive and can lead to vignetting. But, the whole optical path comes into play--secondary size, lateral distance to the focal plane, baffling, etc, so YMMV on this.

I used Newt to design my recently completed 14-1/4" f7 Newtonian, and the results were excellent.

Regards,

Matt L
Glendale, AZ

Floyd,

At f5, you see a little improvement. At f4.5 and below, the difference is dramatic. I would not use an f4-4.5 scope without one.

Regards,

Matt

Lee,

Thanks for the kind words. My creation is all plywood with the obvious exceptions of the truss poles and sundry hardware. The primary is 1979 vintage Coulter, made before their Dob mass production era. It disassembles completely and easily fits into a 1986 Nissan Sentra. The mount is alt-az, similar in design to the Giro (but a bit bigger, heh). Here is another picture, with more to follow.

Matt