11/05/2009
Well, after over 2 years of doing astrophotography and
fighting the MEADE LXD75 mount, I decided to upgrade to a ORION Atlas
EQ-G mount. I have said it before and will say it again, the LXD75 is a
pretty good mount for the money. It's hard to beat for around
$600. However. it has its limitations. The periodic error can be a
problem even if you try to compensate for it using the
Periodic Error Correction function in the mount. The material used
and quality could be better and the computer Hand box seems to have a
mind of its own.
My experiences with the LXD75 have been varied.
Some times it worked almost flawlessly other times I threw up my
hand in frustration and went to bed because it wouldn't track
properly or had some other problem. I must say, though, that I
learn a lot about how to use an equatorial mount and the computer
control.
When I first started this hobby and asked people what
equipment I should look for, most said get the best mount you
can afford. Put the majority of your budget into the mount. Now I know
what they were talking about. The EQ-G is head and shoulders above
the LXD75. This unit is massive. The mount alone weighs over 40 pounds.
The workmanship and quality looks to be superb. All the electronics and
motors are built into the mount shielding it from bugs and weather. When
slewing the mount is extremely quiet. No coffee grinder noise that
you sometimes get with the LXD75. The GOTO's are spot on.
All in all You can't get a better mount for the price
($1500). Certainly there are better mounts available but they
are way out of my budget.
At right is a shot of my current setup.
One of the things that
impressed me was the polar alignment with this mount. Orion places an
image of the big dipper and the constellation Cassiopeia on the reticle
of the polar scope. All you have to do is rotate the RA axis
until the position of Cassiopeia and the Big Dipper match that of
the position of the actual constellations in the sky. Once you
have that all you need do is adjust the azimuth and
elevation screws on the mount to put Polaris in the little circle
that you see in the reticle. I followed that procedure
and was amazed at how close the polar alignment was.
The EQ-G comes with an new dovetail plate
which must be mounted to the OTA rings. In my case the MEADE
dovetail bar did not fit the mounting place on the EQ-G. Two longer 6mm
screws is all that was required to attach the new plate.
Computer controlling the EQ-G required the installation of ASCOM , EQMOD and an appropriate planetarium program. I chose Cartes du Ciel
(Sky chart) because it's one of the more popular program used.
ASCOM ( Astronomical system common interface) and Carte du Ciel
(planetarium program) and EQMOD ( Ascom interface driver for EQ-G type
mounts) are free. You can get
the Ascom system at
http://ascom-standards.org/Downloads/Index.htm . EQMOD is available
from http://eq-mod.sourceforge.net/ and Cates du Ciel is available
at http://astrosurf.com/astropc/.
All programs come with well written documentation.
If you are interested in more info on the EQ-G, Andy's Shot
Glass
http://andysshotglass.com/atlas.html has a great video that
shows you how to align the EQ-G as well as doing the polar
alignment.
Looking forward to many pleasant nights imaging
with the new setup.
11/20/2009
Finally had some decent conditions
for imaging and played around with the EQ-G to get
familiar with how it works. While I was at it, I took a few shots of
M33.
I found the mount to be extremely quiet while slewing and , once
aligned, the GOTO's dead on. In using PHD to auto guide the mount I
found that the graph was almost flat with only a slight ripple in
the RA and DEC axis. Needless to say I am very pleased with
the purchase.
One thing that I found, and was suggested in the
EQMOD users guide, was the that you almost have to use
a GAME PAD to control the mount while you are setting things up
for the night if you are using EQASCOM. It doesn't matter if you are
using the HAND BOX in PC Direct mode or and
EQDIR interface module from
Shoestring Astronomy.
When you use the hand box in the PC DIRECT mode and EQASCOM to
control the mount you cannot use the hand box to manually
move the telescope. Doing so will mess up the EQASCOM connection.
Unless you have a GAME PAD, that leaves you with one
option, using the controls in EQASCOM from the key board on your PC. I
tried using the keyboard for a while but found it almost an
impossible combination. With the finder scope on one side of the OTA and
the PC on the other it was back and forth, got to the keyboard and
move the mount a bit and back to the finder to see how far
it move. and back and forth till the star was in the middle of the
screen. This got old real quick. As you imagine I purchased
a Logitech Rumble Pad 2 and am using that now. You can get a
wireless or USB game pad.
Recently I made another purchase (this hobby
is like a black hole sucking up all your spare cash). While out
one evening familiarizing myself with the new mount I had issues with
the PC direct mode of the Hand box. For unknown reasons the hand box
reset a couple of times. this messed up my EQASCOM connection and
my polar home position. Each time I had to re-align
the mount. Setting it to polar home then restarting EQASCOM,
finding some starts to sync on in the planetarium program and centering
them on the screen. After the third time I gave up and went to
bed.
To eliminate the need for the Hand box I purchase a EQDIR module from
Shoestring Astronomy (see link above). This unit connects to the 9 pin D
connector on the mount where the hand box normally connects. It allows
EQASCOM to talk directly to the mount's controller board without
first going thru the hand box. I haven't had a chance to try this
out yet since mother nature hasn't been cooperative, but will soon.
(stay tuned for updates )
