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1989 Celestron 14" Out of the Woods

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#1 orion61

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Posted 12 February 2013 - 12:07 PM

I just made a trade for a Compustar 14 from a guy I have delt with before. He says the optics were good.
Were the Celestrons from 88-90 out of the Halley Blues?
I traded 2 LX200 Classics and a small refractor OTA for it
about $3200.00 I would guess. It has had the Y2k Chip installed. It was a one owner and is in pretty Mint condition along with an after Market carrying case.
I have always wanted a C14,
Anybody else out there have or had one of these?
I have no trouble with polar alignment so that is no big deal. and I know it is HEAVY!! 122 lbs for tube and forks.

#2 rmollise

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Posted 12 February 2013 - 12:14 PM

Well, not really, not in my experience, but that doesn't mean this isn't a good telescope. I've never owned a Compustar, but have used 'em. You have to understand their limitations, but they can be a lot of fun, and have one of the best hand paddles I have ever seen. Most problems relate to the high speed slew/ramping down and their power hungry nature and desire for a good polar alignment...

#3 orion61

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Posted 12 February 2013 - 12:44 PM

Thanks Rod, I know about the power thats why I have a 12V car battery.
What mount would handle this OTA?
I have a JMI Max DSS computer that works great so even if I don't like the Compustar I could use that on it, I guess the thing I like the best about the JMI is you can unlock it and use it without aligning it again.
I have an LXD-75 but I'm thinking it would be too much.
Possibly an 11"

#4 rmollise

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Posted 12 February 2013 - 01:15 PM

What would handle it? A G11 will handle it, but a Losmandy Titan is the minimum (priced) rig to hold it _right_...

And make sure that is A BIG DEEP CYCLE MARINE battery... ;)

#5 orion61

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Posted 12 February 2013 - 04:37 PM

I have a 7mo old 700 Amp car battery with a carrying handle
I am putting a 5 amp trickle Solar charger on it.
Since I cant store it in the house I might as well let Mother Nature charge it for me.
You had mentioned the C-Star limitations what would they be?
thanks for the imput,
Larry

#6 John M.

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Posted 12 February 2013 - 05:10 PM

I bought my C14 new in February, 1987, so it was likely made in 1986 during the "Halley era." My efforts with the star test suggested spherical aberration of approximately 1/8 wave, no turned edge, low surface roughness (as far as I could tell, since the seeing wasn't "rock steady") and no evidence of zones.

The same night this star test was done (11/13/10) the seeing was quite good (but not "rock steady"), and the view of Jupiter was equivalent (to my eyes) to that of an 8" apo set up nearby ("same" magnifications used in both scopes - 210x in C14, 225x in apo).

Note that on nights of poorer seeing, the apo gives a much more usable high-resolution image, as one might expect. In bad seeing, bright stars seem to have "flaring" or "spikes" in the C14, and focus is ambiguous. In good seeing (as on 11/13/10 noted above), bright stars in the C14 look very much like those in a refractor...round, steady, beautiful - and focus is essentially "snap-to". I live west of Boston, and have never had an occasion like Roland Christen describes where in a C14 in his area in IL that it is difficult to resolve Castor. I should also note that these days the C14 spends all of its time in a rolloff roof observatory, so temperature equilibration is less of an issue than it was when it was brought outside from the basement.

I guess the upshot of my ramblings is that a "Halley era" C14 can be quite good.... :)

Thanks, John

#7 rmollise

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Posted 12 February 2013 - 05:25 PM

I have a 7mo old 700 Amp car battery with a carrying handle
I am putting a 5 amp trickle Solar charger on it.
Since I cant store it in the house I might as well let Mother Nature charge it for me.
You had mentioned the C-Star limitations what would they be?
thanks for the imput,
Larry


Well, like I said, a weak point was the high speed slew and the way it was ramped down when approaching a target. Sometimes made for less than optimal accuracy. Also, needs a pretty decent polar alignment. It could work, but don't expect accuracy like in a modern scope...that's why Celestron shipped a freaking 2-inch 50mm eyepiece with it. ;)

#8 orion61

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Posted 12 February 2013 - 07:54 PM

I believe you can slow the slew rate down, but even if not if it is possible to run without the computer I think I will put the JMI computer on it.
The Max system takes about 3 minutes to align and objects
are always in the field.
But what I like the best is you can unlock the clutches
slew to whatever is of interest the lock it up again without loosing the alignment.
I don't think you can do that with the Compustar can you?
I cant seem to find that information...
thanks Rod

#9 Rick Woods

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Posted 13 February 2013 - 12:57 AM

Welcome to Big Cat Country!

#10 rmollise

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Posted 13 February 2013 - 07:43 AM

No...I don't think so...I believe you'd lose your alignment on the C-Star if you undo the locks.

#11 Geo.

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Posted 14 February 2013 - 01:33 PM

Yeah, the Compustar's standard power supply was rated at 15 amps. You can probably weld with it! There's a lot of inefficency in the system. The Vertex stepper motors are rated at 3 amps. Steppers are generally power hogs, but the stepper driver (the 14 by 6 by 6" box) is built around Texas Instruments silicone power transistors (TIP-107s). The fan should give you some idea of their efficency.

One project I am working on the a PICMicro replacement for the Compustar system based on the work of Ángel Caparrós and the PICgoto Yahoo forum. Here is a circuit that should deal with 3 amp steppers using MOSFET drivers. Reproducted to scale.

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