Gibraltar Magazine Article - March 2020
Gibraltar Amateur Astronomers Society - 2013
Article - Gibraltar Magazine March 2020
Reach for the Stars
Speaking to Charles
Duarte, MAstro (Masters in Astronomy), Fellowship Member of the Royal Astronomy
Society (UK) and head of the Gibraltar Amateur Astronomer’s Society.
By Sophie Clifton-Tucker
After obtaining a Master’s Degree in
Astronomy, I decided to create the GAAS back in 2013 with the help of a small
group of fellow astronomers. The aims were and are to provide a forum for
discussion of astronomy matters and share knowledge, as well as to meet other
fellow stargazers, whether just getting started in astronomy or as a seasoned
observer and/or astrophotographer. It’s also a great way to learn about
telescopes, eyepieces, cameras, and the Universe.
How many members are there? When/where do you
meet? What do you do?
Since its founding in 2013, membership in the
society has been limited to members interested in astrophotography, and currently,
we meet in Spain at least once a month. We have a Facebook page of nearly 700
followers, and Facebook groups of over 2000 members. I would like to establish
a club locally to develop and create awareness of the sky above us, bring
together local people from our community to share our passion for astronomy and
the wonders of the Universe. I receive many requests from local parents asking
how their children can join the society, but without premises, it’s difficult.
I
REMEMBER THE EXCITEMENT I FELT SEEING IT.
When did your interest in astronomy begin?
When I was in school from a very young age, I
was interested in all kinds of science things. There weren’t many books on
astronomy at the time, but I read all the ones in John Mackintosh Hall library.
TV series like Star Trek and Lost in Space when I was growing up did influence
me quite a bit. I do remember the first trips that were made into space, like
the Gemini and Apollo missions. It wasn’t until later in life when I could
afford a telescope, that I saw for the very first time a close-up of the Moon;
I remember the excitement I felt seeing it.
What do you love most about it?
I had to think about this for a long time. But
I think the best thing is being able to share what I have learned about the
Universe with others and enjoy their enthusiasm and amazement.
What has been the most significant/exciting discovery, in your opinion?
There have been many significant discoveries,
mostly in the past fifty years. Still, I will stick with last year’s breakthrough
and one in particular, which proves a theory going back decades. I am talking
about the first image of a black hole, taken using Event Horizon Telescope
observations of the center of the galaxy M87, published in April. This shows
the supermassive black hole at the center of the Messier 87 galaxy, which is
about 54 million light-years away from Earth. The black hole’s mass is
equivalent to 6.5 billion suns.
Scientists struggled for decades to capture a
black hole on camera to prove it exists, since black holes distort space-time,
ensuring that nothing can break free of their gravitational pull — even light.
That’s why the image shows a shadow in the form of a perfect circle at the
center.
How do you see our knowledge of the skies
advancing over the next decade?
In the next decades, we will see a global
competition between nations and the private sector to reach the Moon and Mars
to establish colonies within the next twenty years. India will send astronauts
into space in the next few years. Late this year ESA with Roscosmos aims to
discover life in Mars. SpaceX by 2024 plan to send a crewed spacecraft to Mars.
China expects a spacecraft landing on the far side of the Moon. We mustn’t
forget the USA and Russia, whose sole interest is in the Moon’s minerals.
Would you take part in the Mars mission, given
the opportunity?
Sure, wouldn’t you? I can picture a special
tour: First a stop on the Moon, wearing spacesuits and exploring all its
splendor. Second stop, Mars. There are lots of places to visit there — the
Grand Canyon of Mars, the ice caps, strolling along in the morning in the ice
fog. Our imagination has no limits. Even if there are no tour ships yet, it
will come, but we will need to wait for some years before this is a reality. I
would also like to mention that space is a dangerous place, from cosmos
radiations to super-speedy dust grains that can damage spacecrafts and
astronauts, to gravitation forces that affect our bodies.
WE
WILL SEE A GLOBAL COMPETITION BETWEEN NATIONS TO REACH THE MOON AND MARS.
How much of the observable Universe do we know
about? What is it comprised of? What do you think lies beyond?
Ahh, the million-dollar question. Of the many
ideas that have been discussed over time, the one theory that I feel is most
likely is that outside this Universe, there are a bunch of others all expanding
just like ours, or contracting.
The Universe is expanding. Space itself is
expanding. That much we know from the cosmic redshift of distant galaxies in
every direction and which is measurable. The fact it is expanding means it was
once smaller, and carrying that to its finality is to recognise that it must
have at some point been unified in some form or way. Although I have read a lot
about this subject, there is no concrete answer yet.
Now, to make everybody aware of how little we
know about the Universe. All the stars, planets, and galaxies that can be seen
today make up just 4% of the Universe. The other 96% is made of stuff
astronomers cannot see, detect, or even comprehend.
What planets/constellations are best seen from
Gibraltar/Spain, and in what spots?
Gibraltar’s uniqueness makes it difficult for
seeing. We have a big rock and quite a lot of light pollution, and there are
only a few places you can appreciate the cosmos with your naked eye; one spot
is on the top of the rock, but only if you’re lucky. Remember the night sky
changes throughout the year and constellation position changes as well. If you
look towards the North (North Star-Polaris) you will see Constellations like
Perseus, Cepheus, and a few others rotating around Polaris. Spain is a vast
country, and there are quite a lot of pitch-dark sites nearby. My observatory,
for example, is in Istan (Malaga) mountainside with a night sky reading of 21
SQM.
What equipment would one need? Or where can we
borrow it/use someone else’s?
The simple answer is minimal to get
started. A clear night and a star chart are enough. Star
charts can be bought from most of the larger book shops online, such as WH
Smith. As you gather sky knowledge, buy a reasonably low budget telescope with
a GOTO mount. This will be your starting point, and remember, do not run before
walking, or it will cost you eventually.
Do you have a favourite constellation?
Not sure, I suppose Orion given its
spectacular colorful nebule images once processed. I have been observing and
imaging the night sky for years. For me, the Universe is my favorite space.
Do you have any advice for someone who is
interested in getting into the field of astronomy?
Amateur astronomy should be calming and fun. If
you find yourself getting wound up over your eyepiece’s aberrations or a
planet’s invisibility, take a deep breath and remember that you are doing this
because you enjoy it. Take it only as fast or as slow, as intense or as easy,
as is right for you.
Flip-Flat Equipment
I purchased the Flip-Flat for my FSQ-106 and like it a lot. It’s well-made, and it's a necessary for my camera images, thou I found the included plastic strap for mounting is a bit loose, I can replaced it with a large metal “hose clamp.” if necessary. Using with SGP for automation while I sleep, it’s very handy that it will record flats and close to cover the scope at the end of the night. As others have said, I don’t trust it for bias or darks in daylight, because it seems light will leak in, so I simply record those with the camera unmounted and capped during the night.
This equipment can be a bit over prices I disagree that it is a luxury item... any more than filters, reducers/correctors or PixInsight.
Good quality flats are a requirement and anything that makes taking good flats consistent and reliable is worth every penny. Look at the hundreds of posts on CN about problems processing lights with flats, the majority of which have to do with the quality of the flats in the first place. High quality, astro-dedicated like the Flip Flat eliminate that problem. iPads, cheap LED panels from Amazon and the like are NOT valid substitutes.
New Shed for Small Scope
Observatory
Observatories/ Sheds are highly
individualistic; they reflect the interests, equipment, and personalities of
their owners. Unfortunately, this also means that one individual's dream
observatory might be a white elephant for someone else. As a result, the more
specific observatory plans become, the less useful they are.
Observatories/ Sheds are highly
individualistic; they reflect the interests, equipment, and personalities of
their owners. Unfortunately, this also means that one individual's dream
observatory might be a white elephant for someone else. As a result, the more
specific observatory plans become, the less useful they are.
To store my telescope I used PVC/Aluminium walls with an insulation foam
between the internal and outside walls. to move the shed I connected four
wheels with brakes, the front of the shed has a rolling shatter that lifts with
a cable, this way its easy to just move back the shed from the semi-fixed
mount/telescope.
Having the shed will safely guard my equipment from the elements better than
the previous telescope covered that I had
Calibrating a CMOS - ZWO 1600mm with Pixinslight
I've
been using my ASI1600MM for last month or so, along with the PixInsight BatchPreProcessing
script.
I've read multiple posts to try to
understand what should be the proper settings, and at this stage my conclusions
are:
1600MM-C
1- All exposures should be longer than 0.2
seconds, as the sensor is not consistent under that.
2- Take light frames as usual, at lowest
temperature reasonable (-15C for me these days), with proper gain and offset
(gain 200 and offset 50 for me, as I do narrowband), and for me exposures are
determined using help from the tables in this post.
3- Take matching dark frames: same length,
same gain, same offset, same everything as the lights.
4- Take flat frames: adjust gain as needed
so that exposures of over 0.2s are achieved, giving a SGP ADU readout of around
12,000-16,000
5- Take dark flat frames: same gain and
offset as the flat frames, and same length. For me, this means one set of dark
flats per filter.
6- No bias frames
7- In BPP, put Dark Frames in Darks, Dark
Flat frames in Darks, nothing in Bias, Lights in Lights, Flats in Flats. Dark
Optimization set to OFF. What I understand this does is:
a. Create a master dark of
same length as light frames
b. Create a master dark flat
of same length as flat frames, for each filter
c. Flat frames for each
filter are calibrated with the master dark flat that corresponds to the length
of each filters' flat exposure
d. Flat frames for each
filter are calibrated into a master Flat
e. Light frames are
calibrated with Master Dark (from step a.) and Master Flat (for each filter)
f. Light frames are
star aligned/registered
g. Light frames are
integrated into a Master Light
8- If needed, manually perform a drizzle or
Local Normalization integration
For flats I am using a technique using the daylight instead of a light panel, tests have proven that the quality is much better then a light panel, and its easy to do.
Cover the telescope, Filter Wheel and camera to avoid light penetration to the sensor.
 |
| You need tin paper, tee-shirt and an elastic band |
In SGP I set the ADU level to 25000 with 1000 tolerance.
First CMOS Camera
Modern CMOS Sensors Are Often Superior to CCD Sensors
CMOS sensors have undergone significant upgrades in recent years, in many cases surpassing CCD sensors. Their high speeds (frame rate) and resolution (number of pixels), their low power consumption and, most recently, their improved noise characteristics, quantum efficiency, and color concepts have opened them up to applications previously reserved for CCD sensors.
The improvements to CMOS technology and the strong price/performance ratio in these sensors make CMOS sensors increasingly attractive for industrial machine vision. In particular, the very high frame rates that can be achieved, almost without any compromise in image quality, are one of the primary hallmarks of the current generation of CMOS.
CMOS development over taking CCD
My New CMOS Camera
CMOS sensors have undergone significant upgrades in recent years, in many cases surpassing CCD sensors. Their high speeds (frame rate) and resolution (number of pixels), their low power consumption and, most recently, their improved noise characteristics, quantum efficiency, and color concepts have opened them up to applications previously reserved for CCD sensors.
The improvements to CMOS technology and the strong price/performance ratio in these sensors make CMOS sensors increasingly attractive for industrial machine vision. In particular, the very high frame rates that can be achieved, almost without any compromise in image quality, are one of the primary hallmarks of the current generation of CMOS.
CMOS development over taking CCD
- High speeds (frame rates)
- High resolution (number of pixels)
- Strong dynamic performance
- Low power consumption
- Improved noise performance
- Improved quantum efficiency
- Improved color concepts
- Good price/performance ratio
What
is a CMOS sensor?
There
are two types of image sensors for industrial cameras on the market: CCD and
CMOS sensor. The right sensor for any given job is a case-by-case
question. At the same time, the trend seems to be toward CMOS sensor technology
as the wave of the future. This should come as no surprise, as CMOS sensors
have made major strides in recent years in two important parameters for area
and line scan cameras, namely image rate and noise level. Since the beginning
of 2015, it has become official that CMOS technology will be the future
technology.
 |
| ZWO 1600MM PRO |
One beautiful thing about the 1600MM pro is it's huge size
chip. The MN34230 CMOS sensor comes with a resolution of 4565*3520 and has a
3.8um pixel size, which makes it a great camera for imaging widefield objects
with my 105MM refractor. Another important reason for me to buy this camera is
that it also contains DDR3 256MB memory, which should help to improve data
transfer reliability and minimize amp glow caused by a slow transfer speed when
using a USB 2.0 port on your laptop or computer to connect the camera.
Moreover, the camera has a low read noise of 1.2e.
Testing noise and ampglow levels
You can guess that the first
thing i did was taking some dark frames and checking the amount of noise and
amp glow at various shuttertimes, while cooling the camera at -25 degrees
celcius (77 degrees fahrenheit) at unity gain (139) setting. I went as far as 5
minute (300s) frames.
GM2000
My new mount 10Microm GM2000 replaces my old AP 1100, my motivation for the upgrade grew
out of the realization that my astrophotography
quality needed a with dual decodes which lack the replaced mount. Two
things matter to me: avoiding wasted time during an overnight session (caused
either by images thrown away due to tracking errors or by time spent repeatedly
trying to properly frame the desired variable star), and image quality (which
affects photometric – brightness measurement –
accuracy). This is a personal expression, but never got the reliability
to the point where I could trust it to work during unattended overnight
sessions.
What made the GM2000 so
attractive is that it uses absolute encoders on both the declination and RA
axes, which virtually eliminates periodic error. The company claims that
tracking error is routinely less than 1
arcsecond, What appealed to me is that
10Micron doesn't sell any version of the GM2000 without absolute encoders,
which has permitted them to optimize the entire control system around the use
of the encoders.
Installing the GM2000 onto my
pier was straightforward, just requiring a few holes and bolts. The most
difficult part of the installation was wrestling the
30 KM of mount up onto the pier. The image below is a picture
showing the new mount, telescope, and camera.
It then took a couple of weeks to finish upgrading my software to
handle the computer interface to the GM2000 and
to build a "mount model" in the GM2000 firmware.
To build a mapping
points model there are third parties software , this are ModelCreator or Mount
Wizzard. It a be tricky to setup the communication channel , but once you
connect it a great program.
The firmware has a very nice
polar alignment tool, eventually 5 arcseconds
away from perfect.
This time I used
Polemaster to assist me , thou you need first to do a three stars alignment
followed by the polar alignment and if you use the mount PL you would need
again to do the three stars alignment.
The general "feel" of the mount is wonderful. The GM2000's
firmware seems solid. When you execute a goto, the mount does it quickly and
accurately, the same every time. When things go wrong, you don't need to cycle
power to get the mount working normally again; instead, just fixing the problem
makes the mount happy again.
The mount performs "two-axis tracking," with both the declination and RA motors involved in the tracking process. The mount's pointing model is translated by the firmware into both a declination tracking rate and a RA tracking rate. Thus, the two-axis tracking is able to compensate for all of the known elements of small misalignment. I've run the mount last week for the first time given that when setting up the connection to SGP it platesolving was not aligned with the mount RA/DEC coordination. The issue was the mount software memory stick firmware version, thinking that it was latest in reality its was old, quite old (1.22) when the current update with 1.5. After realizing this and quite annoyed that they sold me a nearly two year old mount (new , but old if you know what i mean) I did a fully automates of five hours overnight sessions, connected and sync to the dome.
For my exposures (up to about 6 minutes), there is no visible tracking error.
Typical star images have FWHM widths of about 1.9
pixels.
Mount in action
PoleMaster and SharpCap Polar Alignment Experiances.
The QHY PoleMaster
The QHY PoleMaster electronic polar scope was
designed to make your polar alignment routine easier, although I do have the
RAPAS scope by Astro-Physics, this scope is very versatile and can be use jointly with
any other polar alignment software like the SharpCap (which I will talk later) or PoleMaster . One point to
mention is no matter which camera tracker or telescope mount you’re using, when
it comes to astrophotography, accurate polar alignment is
critical.
If you have ever struggled to polar align your
telescope mount with the north or south celestial pole, the QHY PoleMaster or
SharpCap may just be your new best friends.
The QHY PoleMaster delivered exceptional results for me on my
first night out with it. The dedicated polar alignment software was easy to
use, and the camera produced a crystal clear image of the star field surrounding
the north celestial pole, you just have to be patient as you will need a dark sky
before starting.
Polar Alignment speed,
accuracy and experience improvements with the QHY PoleMaster:
I can polar align
faster, at dusk
I using the PM to improve the current method I
use with the RAPAS for alignment which was
fast, this one is faster.
I can monitor and confirm my polar alignment at
any time
No more 2 or 3-star alignment routines if
necessary but again is a personal choose
The spot-on accuracy of the PoleMaster means
that my AP mount 1100gto will only need to swell to a star at zero
declination (South sky) and once centered on the scope finder or PC do a Recal
(press bottom left hand corner button once and press 9).
.
QHY PoleMaster Alignment Camera Specifications:
Field of View: 11 degrees by 8 degrees
Interface: Mini USB 2.0
Resolution: Approximately 30 Arc seconds
Weight: 115 g (0.25 lb)
What’s included in the box
This PoleMaster was sent to me from High Point Scientific for review. The
team at High Point made sure to include the necessary adapter for my EQ
telescope mount. Here is a look at everything that comes with the PoleMaster:
PoleMaster camera body
Lens cap with a lanyard
Mini USB 2.0 cable
Mount adapter
Mount adaptor cap
M4 hardware for attaching the adaptor
Allen key for lens focus adjustment
Fastening the PoleMaster to your telescope
mount
The PoleMaster I am using is for my Astro-Physics
1100GTO EQ mount, and I have fastened it to the mount using the dedicated
QHY adapter for this model. The hardware was easy to install, and the materials
used and overall finish of this device is attractive.
The adapter for my mount came with a tiny Allen
key to adjust tension, so I could securely lock the PoleMaster into the front
of the polar axis scope of the mount.
The QHY PoleMaster adapter for the AP Mount
9000 & 1100
There are two parts to the mount adapter for
the PoleMaster, the camera base disc that attaches to the camera body, and the
camera mount ring that you need to secure to the mount. You secure the camera
base disc to the mounting ring using a thumb screw.
For the mount adapter I used, there were three
tiny grub screws to tighten using the supplied Allen key to lock the adapter
into place.
The device connects to my Hub via a Mini USB
2.0 cable, with miniature locking screws to avoid yanking the cable out by
accident. I wish more of my device connectors had this. The manual
instructs you to position the USB port of the PoleMaster to the left hand side
when looking at the device head on.
I ran the mini USB 2.0 cable from the PoleMaster
into my recently Pegasus powered USB hub, which consolidates the various
astrophotography devices I have running to a single USB cable into my laptop.
The adapter allows you to take the PoleMaster
off of the mount while not in use or in storage, but I think I’ll leave it
right where it is. The tiny camera adds no weight to my rig and maintains a low
profile.
I’ll just have to make sure I don’t bang
anything against the device by accident when setting up. The included lens cap
should stay on the PoleMaster when not in use to protect the lens.
Software and Downloads
All of the software and drivers needed to run the PoleMaster device
were found on the QHY website. The company has recently updated their site,
which lead me on a bit of a wild goose chase.
Rather then using the URL printed on the green
card that came with the camera, I simply “Googled “QHY PoleMaster Driver” to
find the appropriate section of the QHY website.
Here, I downloaded the latest stable driver for
the PoleMaster, along with the dedicated software needed to communicate with
the camera and control parameters such as gain and exposure length.
With the 2 downloads unpacked and installed, I
ran the PoleMaster software on my field laptop with the camera connected. The
QHY PoleMaster manual was to-the-point and helpful through this process, and
instructed me to click the “connect” button.
I heard the reassuring “new device connected”
chime on my Windows 10 OS after plugging in the PoleMaster, so I new the camera
was successfully recognized by my PC.
After hitting the “connect” button, the
PoleMaster delivered a live-view loop of the stars in the northern sky. My mount
was already partially polar aligned to my latitude at 36 degrees north, and pointed
towards Polaris from my observatory.
The PoleMaster camera lens has an 11 x 6 degree
of field of view. This means that the pole star should be visible if the mount
has been roughly polar aligned.
Even though it was not completely dark out yet,
I could see a formation of stars in the display screen right off the bat. After
zooming out to 75% view, the north star, Polaris was obvious.
Using the PoleMaster Software
The PoleMaster software user interface.
The first thing you’ll want to do is adjust the
gain and exposure settings so that it is easy to identify the pole star and a
number of adjacent stars in the field.
The software walks you through a simple process
of identifying and confirming the pole star. The process involves matching an
overlay of star positions with your current view of Polaris and surrounding
stars.
The rotate tool on the left hand sidebar lets
you rotate the star pattern overlay using your mouse or using the computer
arrows to move the sidebar level.
Then, you are asked to rotate the RA axis of
your telescope mount to determine the rotation of the mechanical axis. By
rotating your mounts right ascension axis by 15 degrees or more, the software
can confirm this value.
This can be confusing the arrow showing on your
screen shows an clockwise rotation, the star rotation must be moving
anti-clockwise, so when using the Hand_Control/HandPad move the stars
anti-clockwise. when the manual clearly states that this must done using the
hand controller or mount control software.
Fine tuning my the polar alignment accuracy of
my telescope mount using the QHY PoleMaster.
Next the on-screen prompts tell you to confirm
the center of rotation. Eventually, you will get to a point where the
application displays a small green circle. This is exactly where the pole star
needs to be. At this point, the ultra-fine adjustments you make to your polar
alignment are far beyond what’s possible with the naked eye.
Atmospheric Refraction
The PoleMaster has an option to enable a
feature called atmospheric refraction to further improve your polar
alignment accuracy. This feature asks you to input your coordinates,
temperature, and pressure. For atmospheric refraction to work correctly, the USB
connector on the PoleMaster must be facing east.
Owners of the PoleMaster have recommended to
start the polar alignment routine with your telescope to the west instead of
the home position. 2 moves or more than 30 degrees can be difficult from the
home position, so if the telescope starts in the west it is not an issue.
If you do not remove the PoleMaster from your
telescope mount between astrophotography sessions, you can reuse the centering
procedure from your previous polar alignment. However, if you are using the
atmospheric refraction feature, you’ll need to remember to adjust the
temperature and pressure settings for that night.
SharpCap
Some weeks back I began to hear about Sharpcap’s polar alignment tool. Sharpcap
is compatible with just about any camera out there as long as there is an ASCOM
driver for it. Best part? Sharpcap is free.
A visit to the Sharpcap website revealed I had
everything I needed to give this Polar Alignment Tool a try: a compatible
camera (guess what my QHY polemaster camera!!) and all I needed was one of those increasingly
rare clear nights to give it a try. I read over the instructions a time or two
in preparation, but, frankly, there isn't much to the procedure once the camera
is connected to Sharpcap. Press an onscreen button a few times, move the mount
once, and adjust the polar alignment with the mount’s altitude and azimuth
adjusters.
That nice night finally came, and saw me
setting up my AP-1100GTo mount. I put the telescope in normal “home” position,
that is, pointed north with the counterweight “down.” (NOT Tracking) the QHY polemaster
was already was inserted into the guide scope and connected to the Pegasus USB
hub/ computer.
First task was getting an image, a focused
image.
Once I was close to focus, the sensitive QHY
was producing more than enough stars to meet Sharpcap’s requirements in a mere
1 seconds of exposure. To work, the program needs 15 stars within 5-degrees of
the pole, and according to the information on the first polar alignment screen,
I was getting around 20.
Ready to go, I clicked Sharpcap’s Tools menu
and selected “Polar Align.” I was then presented with Screen 1, shown here.
Stars marked in yellow are the ones Sharpcap is using for plate solving the
star field (figuring out which star is which). I didn’t worry about that, just
let the program think for a little while as the frames rolled in. Shortly, the
“Next” button was enabled, meaning I was ready for step 2.
After pressing “Next,” screen 2 was presented and I was instructed to rotate the mount 90-degrees in right ascension. I did, so, moving the mount roughly 90-degrees to the east. (remember NOT TO USE the hand-control to rotate the scope).
Sharpcap then studied a few more frames in
order to determine where the Celestial Pole was and what I needed to do to aim
the mount there. Once it knew these things, the Next button was enabled again.
After pressing Next for a final time, a star
was highlighted in yellow and there was a yellow arrow connecting it to a
circle, my target . The task was to move the mount in altitude and azimuth so
as to position the star in the little circle, not unlike what you do with a
polar bore-scope (by the way, you don't need to return the mount to home
position before adjusting; leave it rotated 90-degrees). As you move in the
proper direction, the yellow arrow gets shorter and shorter and eventually
disappears. It is then replaced with a pair of brackets around the target to allow
fine tuning. As you center the star in the target circle, the brackets will
move closer and closer together.
How easy was this to do? Quite easy AFTER I
understood exactly how to do it. In the beginning, I was fairly far from the
pole, with the arrow extending off screen. I’d been told that at this stage it
was best to adjust while watching the error numbers Sharpcap displays instead
of worrying about the arrow.
These numbers (degrees, minutes, and seconds)
indicate how far you are from the pole. They aren’t labeled as altitude and
azimuth; instead they read “Up/Down” and “Left/ Right.” Sounded easy to me. I’d
adjust the mount’s altitude until the Up/Down number got smaller, and the
azimuth till the Left/Right went down. Alas, that didn’t work at all.
It turned out there was a catch, and until I
understood what it was, I was all at sea. Up/Down does NOT mean the mount’s
altitude, and Left/Right does NOT equal azimuth. Instead, these error numbers
relate to directions onscreen (that's what I thought, anyway; see the addendum
at the end of the article).
In just a minute or two, I had the program
indicating my distance from the pole as under a minute (it when from 55sec to
15 sec) showing as an 'excellent' Polar Alignment!!
The accuracy? I swell to a star at zero
declination south and just need to move the star with my hand-control a bit to the centre
of the screen to calibrate my AP 1100gto mount.
Advantage above Polemaster
Basically, SharpCap takes two pictures near the
pole and analyzes them to judge the accuracy of your Polar Alignment.
SharpCap uses plate solving to scan the
images and then tells you how much you need to move your mount to increase the
accuracy of your Polar Alignment. It connected to APCC automatically using it
plate solve and altitude position.
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