Date   

Re: Dead AP900 GOTO

Larry Denmark <kldenmark@...>
 

Sorry to hear that Bob :-(

I seem to have fried my AP900. Tonight, I set up to use the ST4 to
autoguide the AP900. I connected the relay cable to the autoguider
port on the GOTO control box (using the cable supplied with the ST4),
and everything else as normal. After I fired up the ST4, I turned the
power on my mount. The keypad lighted up ok, but won't slew and
I can't get past the Startup menu. The mount was working fine yesterday
(without the ST4) and was still set up from last night. I tried
disconnecting the ST4 and connecting a different keypad, but with the
same result. The light on the control box lights up, but otherwise the
mount seems dead.
What color is the little light on the control box? Since you were using the
mount the evening before the 900 "died," could it be your battery (if that's
what you use for power) died and not the mount? (E.g., did you turn off the
mount and leave a dew heater on?) Sorry for the overly simple suggestion,
but there is no category of simple goofs that I have failed to make.

I doubt it had anything to do with the ST-4... but is this the first time
you've used the ST-4? If so, are you certain you used the correct cable (or
did you make your own and use a standard telephone wire sequence?).

Larry
--

Larry Denmark
kldenmark@att.net
http://home.att.net/~kldenmark/towardinfinity


Dead AP900 GOTO

rck <rkuberek@...>
 

I seem to have fried my AP900. Tonight, I set up to use the ST4 to
autoguide the AP900. I connected the relay cable to the autoguider
port on the GOTO control box (using the cable supplied with the ST4),
and everything else as normal. After I fired up the ST4, I turned the
power on my mount. The keypad lighted up ok, but won't slew and
I can't get past the Startup menu. The mount was working fine yesterday
(without the ST4) and was still set up from last night. I tried disconnecting
the ST4 and connecting a different keypad, but with the same result.
The light on the control box lights up, but otherwise the mount seems
dead.

Any advice would be appreciated.

Regards,
Bob Kuberek


2-star alignment routine

Michael Roth
 

Fellow members:
I need some help. My telescope is orthogonal and the north polar
alignment procedure works perfectly. However, the 2-star procedure
consistently brings the two stars selected to the exact same spot
well off the crosshairs. The iterations bring the respective stars
only so close to the crosshairs but no closer. On one try I used two
stars east of the meridian, on another I used one star east of the
meridian and one star west, and on yet another attempt I used two
stars west of the meridian. The results are peculiarly consistent.

Its a 600E, I start with the mount roughly polar aligned, the first
few iterations progress towards alignment but only so far. Each of
the stars used had good "contrast" in RA and DEC, that is, 6 hours
and 40 degrees(Dubhe/Antares) and (Altair/Schedar). I am also
correcting with 1/2 alt/az and the remainder with the buttons.

Any advice please?

Mike Roth


Re: Star alignment error

Chuck Hancock
 

eratum:
Seriously, the stars Alpheratz and Elnath once were part of two
constellations: Andromeda and Pegasus, and Taurus and Auriga (the
Waggoner), respectively.

Yes, the catalogs of Hyginus and Ptolemy. g Seriously, the stars
Alpheratz and Elnath once were part of two constellations, Andromeda and
Pegasus. Supposedly the translation for Alpheratz is The Head of the
Woman in Chains.
Best regards,
Chuck Hancock DMD

McDonough GA USA


Re: Star alignment error

Chuck Hancock
 

Yes, the catalogs of Hyginus and Ptolemy. g Seriously, the stars
Alpheratz and Elnath once were part of two constellations, Andromeda and
Pegasus. Supposedly the translation for Alpheratz is The Head of the
Woman in Chains.

See the January 1999 Sky & Telescope, pages 101-103.

chris1011@aol.com wrote:
...


OOps! Some stars may be in different constellations, depending on catalog.
--
Best regards,
Chuck Hancock DMD

McDonough GA USA


Re: Star alignment error

Roland Christen
 

In a message dated 8/18/00 8:09:13 PM Central Daylight Time,
cspratt@islandnet.com writes:

<< star ALPHERATZ when used as a calibration star
lists the home constellation as PEG for Pegasus. >>

OOps! Some stars may be in different constellations, depending on catalog.

Roland


Star alignment error

Chris Spratt
 

I noticed that the star ALPHERATZ when used as a calibration star
lists the home constellation as PEG for Pegasus. This is in error as
the constellation should be AND for Andromeda. The telescope does
point to the right object just the constellation location details are
in error. I'm using Version 2.6. Anyone else spot this besides me?


Re: accuracy with planetary pointing

Roland Christen
 

In a message dated 8/17/00 9:10:32 PM Central Daylight Time,
terry@venus.sunquest.com writes:

<<
I was simply confused because the original question on this thread was about
inaccuracy in locating the planets and the suggested fix was to change the
timezone. >>

Of course, you have to understand that the planets move from hour to hour,
and will be off slightly if the wrong time has been entered. They are also in
slightly different locations with respect to the background stars depending
on time and location on the earth. This is especially so for the Moon. We
have checked and triple checked our planetary positions against other
standards and against The Sky software, and are within 30 to 60 arc seconds
in position.

Roland Christen


Re: accuracy with planetary pointing

Terry R. Friedrichsen <terry@...>
 

it uses universal time, but most people don't have
access to this number, so me made it so that they can input their local
time, and calculate the universal time from it.
Sounds like a good idea to me.



I don't understand the problem? Do
you think this makes the pointing accuracy less? I can assure you that it
does not for the vast majority of users.
I was simply confused because the original question on this thread was about
inaccuracy in locating the planets and the suggested fix was to change the
timezone. I wanted to understand how that would fix the problem.

I still don't understand the bit about "for the vast majority of users", but
I'm willing to wait for my mount and manual ...

Terry R. Friedrichsen

terry@venus.sunquest.com


Re: accuracy with planetary pointing

Terry R. Friedrichsen <terry@...>
 

Yes, of course, but "civil time" is not accurate when it comes to stellar
time. Civil time can be off by as much as 1/2 hour ...
And, as you pointed out, it can get even worse. Thanks to the "first dawn
of Y2K" flap back on January 1, there is an uninhabited island out in the
Pacific that's something like *5 hours* ahead of mean solar time. (So it
is logically west of the International Date Line even though it is physic-
ally way *east* of the International Date Line, which made the sunrise that
should have been the morning of December 31 became the morning of January
1, by fiat.)

Problems like this are exactly why I don't understand why the mount uses
civil time at all.

(There are lots of fun facts about timezones codified in the Unix zoneinfo
files. Have you ever heard of "Pacific Presidential Election Time"? Or
didjuh know that Hawaii observed Daylight Savings Time for *one day* in
1933?)



There is no way
around, except to adjust the time zone and clock time to correspond to
what is actually happening on the sky.
If you're using civil time, yes. I just find it odd that the mount would
have anything to do with civil time at all, when latitude/longitude/GMT
solves all these problems, including meridian swap.



That is fixed by your initial synchronization on a known star.
So if I understand what you're saying here, you tell the mount the civil
time, which it uses to compute when to do the meridian swap. Synchro-
nizing on a known star then tells the mount how it is oriented relative
to the sky, and it goes from there.

This raises LOTS more questions, but I'm gonna wait for my mount to get
here so I can absorb the manual before asking ...

Thanks for the response.

Terry R. Friedrichsen

terry@venus.sunquest.com


Re: accuracy with planetary pointing

Roland Christen
 

In a message dated 8/17/00 9:19:49 AM Central Daylight Time,
terry@venus.sunquest.com writes:

<<
Problems like this are exactly why I don't understand why the mount uses
civil time at all.
>>

I doesn't use civil time, it uses universal time, but most people don't have
access to this number, so me made it so that they can input their local time,
and calculate the universal time from it. I don't understand the problem? Do
you think this makes the pointing accuracy less? I can assure you that it
does not for the vast majority of users. Even if you told the mount you were
in Australia, you would still find every star and deepsky object in your
eyepiece.

Roland Christen


Re: accuracy with planetary pointing

Terry R. Friedrichsen <terry@...>
 

If you are in France, you should use time zone 0 in your location and
turn the clock back by 1 hour. This will make your solar system objects
come in closer.
OK, I'm just a lurker here; my 1200GTO isn't due yet for another couple of
months. So if I should just shuddup and wait for the user manual, some-
body *please* tell me so.

But I'm trying to understand the situation here. It sounds like you'd be
jiggering the *civil* time to help with planetary position calculations,
and that makes no sense to me.

I would have thought you'd just tell the mount its latitude and longitude,
set its clock to Universal Time, align it, and be off and running (or may-
be you hafta set the time on the hand controller; I'm not really clear on
what the division of labor is between the two). In any case, I can't under-
stand what your time zone would have to do with astronomical object position
calculation, planetary or otherwise.

Could someone Enlighten me, please?

Thanks!

Terry R. Friedrichsen

terry@venus.sunquest.com


Re: Voltage Drops

rck <rkuberek@...>
 

Hi Tim,

Tim Khan wrote:

How "Clean" is the DC-DC converter and did you put a
large capacitor at the output? Also, wouldn't you want
to have a 3-4 amps converter instead of 1-2 amps?
Tim,

The converter is very clean. It's rated for 9 amps. I believe
there's a large capaciter on the converter.

The documentation for the AP mount says it will take up to
15 Volts.

Regards,
Bob Kuberek


Re: accuracy with planetary pointing

Roland Christen
 

In a message dated 8/16/00 3:09:07 PM Central Daylight Time,
terry@venus.sunquest.com writes:

<<
But I'm trying to understand the situation here. It sounds like you'd be
jiggering the *civil* time to help with planetary position calculations,
and that makes no sense to me.>>

Yes, of course, but "civil time" is not accurate when it comes to stellar
time. Civil time can be off by as much as 1/2 hour if you are located near
the edges of your time zone. Further more, in the case of Europe, some
countries have chosen to be in the wrong time zone. In their case, at 12 noon
"civil time" the sun is 2 hours off the meridian in the summer, and 1 hour
off in the winter. If you use this civil time, then the calculated zenith
crossing faithfully recreates this 1 hour discrepancy. There is no way
around, except to adjust the time zone and clock time to correspond to what
is actually happening on the sky.

In the case of the US mainland, the most you will be off with the meridian
swap would be about 1/2 hour at the edges of the time zones. This applies
ONLY to the meridian swap, has nothing to do with the pointing accuracy of
the mount. That is fixed by your initial synchronization on a known star. We
always know where any other point in the sky is, because the distances are
known and fixed.

Roland Christen

>>I would have thought you'd just tell the mount its latitude and longitude,
set its clock to Universal Time, align it, >>


accuracy with planetary pointing

visonneau-vin <visonneau-vin@...>
 

Hi
I have some trouble with my 900Gto when i want to see object of solar
system,the pointing is always out.My ota isn'nt perfectly orthogonal but the
precision when i point deep sky oject is sufficient.The version of my keypad
is 2.4,is there a problem with my keypad,i don't remember exactly but i
thought there is some problem (bad accuracy for system solar oject) with
oldest version.
When will be available the download area?
Bye
Vincnet from france


Re: accuracy with planetary pointing

Roland Christen
 

In a message dated 8/16/00 1:05:30 PM Central Daylight Time,
visonneau-vin@infonie.fr writes:

<< have some trouble with my 900Gto when i want to see object of solar
system,the pointing is always out. >>

If you are in France, you should use time zone 0 in your location and turn
the clock back by 1 hour. This will make your solar system objects come in
closer. For some reason, France has chosen to be in time zone 1, but this is
really only accurate for the real time zone 1 which is centered at 22.5
degrees east, near Belgrade. There have been no changes in the calculations
of the planet data since the beginning. Even the latest version that we are
working on is still the same.

Roland Christen


Re: Voltage Drops

Tim Khan
 

How "Clean" is the DC-DC converter and did you put a
large capacitor at the output? Also, wouldn't you want
to have a 3-4 amps converter instead of 1-2 amps?

I've thought about doing this: a 12V battery and a 2v
battery in series. The 2v battery should only be sized
for the mount and not the accessories. Run the
accessories with 12V only, and the mount on 14V. The
surface charge will probably start out at 17v but
should drop to 14v in an hour of use.

Question is Will the mount handle over voltage without
any problems? Perhaps A-P can Comment.

Tim





--- rck <rkuberek@ix.netcom.com> wrote:
To deal with the voltage drop problem with the AP
mount, I've
designed the following circuit:

http://www.ccdastronomy.org/power2.gif

Initial tests of the DC-DC converter are very
promising, but
it's only 66% efficient, which is the reason I run
only the mount
off it in the system. This configuration also
minimizes the amperage
requirement for the converter, making it conceivable
to use
a Nesco 30W unit.

Comments are very welcome.

Regards,
Bob Kuberek




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Re: Voltage Drops

Roland Christen
 

In a message dated 8/16/00 8:02:26 AM Central Daylight Time,
timkhan@yahoo.com writes:

<<
Question is Will the mount handle over voltage without
any problems? Perhaps A-P can Comment. >>

I have run the system at 16 volts with no problem.

Roland Christen


Voltage Drops

rck <rkuberek@...>
 

To deal with the voltage drop problem with the AP mount, I've
designed the following circuit:

http://www.ccdastronomy.org/power2.gif

Initial tests of the DC-DC converter are very promising, but
it's only 66% efficient, which is the reason I run only the mount
off it in the system. This configuration also minimizes the amperage
requirement for the converter, making it conceivable to use
a Nesco 30W unit.

Comments are very welcome.

Regards,
Bob Kuberek


Re: Power

rck <rkuberek@...>
 

Paul Hyndman wrote:

Yipes!!! Are ya' sure you cooked it? The cigarette lighter adapter is
fused. Of course if you (ahem) custom wired it without a fuse then
awww shoooot!
Indeed, the adapter is fused...stay tuned!

Regards,
Bob K.