Amateur astronomy tips and advice
(Page subject to regular improvements)
Getting started
One day you wake up and decide, "I want a closer look at the
stars." If you were like me, you were lucky enough to come to this decision when
you had a financial surplus. If not, then you will probably have to be dedicated
to maintain the interest when you have no means to view the stars up close. This
does not mean however, that you have to give it all away until you save up. This
is your opportunity to prepare! Pray to God to help out with the rest. If it's
in His will, nothing will stop Him!
Know your sky first
Get yourself outside at night. Go as many times as you can.
Note prominent stars and patterns. Look at where certain stars are at certain
times. You will very quickly start to see how the sky moves through the night,
through the week, month and year. Seeing these things will give you a real sense
of where you are in the solar system. You will notice things like planets and
the moon, the line they all seem to follow. Like runners all on different lanes
of a circular track, except viewed from the side, the planets seem to catch up
to each other, lap each other, stop and even seem to go backwards at times. See
how the milky way rotates through the night as well, and how you can only see
some parts of it for only part of the year.
A star chart or wheel (planisphere) is a very inexpensive way
to learn the sky. These are easily found in shops and can even be found on the
internet. Start with the simple things, like identifying the phases of the moon.
Find and use a major constellation (easily recognisable one) to find north or
south. Some constellations are hard to identify and visualise. a lot of them
don't look anything like what they say they represent. All you need to do here
is find one that you do recognise. Find it on your chart and find it in the sky.
Turn your chart and orientate it to face the same way. Like some people I know
turn their street directory when they turn a corner and change direction. It is
a good way to begin to get your bearings. Once you are more familiar with the
sky, you won't need to rotate your chart.
Getting to know the sky with the naked eye is also a great
start, because it will help you later when you want to navigate to other objects
using binoculars or a telescope. You will appreciate what you see far more when
you do.
Reference books and sites
Make sure you buy up to date books. Pictures are fine and helpful but make
sure the information is detailed and up-to-date! Don't worry too much if you
can't grasp a lot of the stuff in the books at first. You will learn a lot from
them and grow into them. There's nothing worse than buying astronomy for dummies
and finding that you learn the book in a day. I recommend a good star-hopping
guide at least. There are online star catalogues like the Messier catalogue
http://www.seds.org/messier/xtra/history/m-cat.html , Caldwell catalogue
http://www.seds.org/messier/xtra/similar/caldwell.html and NGC catalogue
http://www.astrosurf.com/benoit/ngc.html . Shop around on the net. You don't
have to pay full price in a shop for a paper dust cover that is not torn. You
will probably get it wet, dirty and all sorts in your first night outside
anyway. I also got a lot of good info from news agency magazines. Go and have a
browse there too.
Cold nights
Nothing kills interest more than discomfort. If you freeze
your bottom off, then chances are, you will not enjoy yourself and neither will
anyone with you. You and they will be far less inclined to come back to it and
learn more next time. Remember to rug up in layers. If you are going long
distance to get away from city lights, take as many comforts with you as you can
lay your hands on. A thermos flask full of hot chocolate, coffee or soup makes a
world of difference and partaking in it only adds to the pleasant experience.
Some background music coming from your car (quietly) can also provide a bit of a
social atmosphere. Don't light a fire though, as looking at it will ruin your
night vision. DO NOT TAKE ALCOHOL! Alcohol seriously affects your vision when it
comes to astronomy. Some very faint objects viewed through a telescope are hard
enough to see with normal vision. Besides, chances are that you drove to
your viewing site.
Best conditions
Ideal observing conditions are as follows:
-
No moon, unless you specifically wanted to observe the
moon.
-
No city lights. Get as far away from all artificial light
sources as possible. Light refracts off all small particles in the air, like
humidity, smoke, fog, smog and dust. Even though the sky may look dark, the
light is still there. You will notice if you do any photography that the
light will wash out the picture the longer the shutter is left open. Light is
bad for astronomy, so get away from it if you can.
-
Altitude. The higher, the better. The air is generally
drier and clearer up high. You will notice that the bottoms of the hills and
valleys get the fog settle in it first and dew covers everything. Not only
will you and your equipment get a lot damper, but it could cut your night
short if fig impedes your view.
-
No wind. Whilst setting up on a hill can be good, it is
very susceptible to wind. Try to find a sheltered site. Wind is one of the
most annoying conditions and it's usually when I pack up and go home.
-
Cold nights. Winter. Cold, clear and dry makes for
excellent viewing.
-
Azimuth. Most objects are clearest and least distorted when
they are directly overhead. If there is something specific you are out to
view, try to check the times and go out when that object is at it's highest
peak in the sky.
Spontaneity
Sometimes you can plan to view a celestial event. My luck has
been that if there is something special happening up there, it's overcast.
Phooey! Get out there on the spur of the moment. If you look up and say, "Wow!
What a beautiful clear and dark sky!" Then get your gear out and go for it!
Encourage your friends to do the same. Spontaneity is a wonderful thing!
Dark adaptation
When you go out into the dark, you will notice that you won't
be able to see very well. As time passes, you will begin to notice things around
you. Features on the ground, the chair you tripped over earlier and more stars
than you could see at first. It takes the average person 5 minutes to see
better, but 30 minutes to fully adapt to the dark. Avoid trying to show others
through the eyepiece of the telescope until they have become adapted. They will
see nothing and be disappointed. If you need light, use a red filter and make it
as dim as is needed to get the job done.
Binoculars
Binoculars are an astronomers best friend. I wish I had some. I broke my last
set. You will often see numbers like 7x50 written on binoculars. The first
number represents the magnification while the second number is a size of the
aperture in millimeters. Aperture means “opening” (also known as objective lens)
and is where light enters the binocular.
The bigger the objective lens, (aperture), the more light it can let in and
gather. Your eye's pupil will dilate only so much, so 7 millimeters for the
eyepiece lens is usually plenty. For maximum effective light-gathering and
brightest image, the exit pupil should equal the diameter of the fully dilated
human eye—about 7 mm, reducing with age. Light gathered by a larger exit pupil
is wasted. Good quality optics is what is needed here. Keep your budget
in mind but don't skimp if you don't have to or you may regret not spending the
extra few dollars.
Telescopes
As I am really no expert on the subject, I can only offer you my own
experiences as I see them. I had little or no help from anyone as far as advice
or instruction was concerned, so I have mostly learned astronomy on my own
through the internet, books and field experience with my own 'scopes.
I started back in 2000 on an impulse at a retail shop that sold cheap
telescopes. I had a spare couple of weeks pay ($1000) so I thought, "What the
heck? I've always been interested, a sci-fi fan and always wondered in awe at
space documentaries. I bought the most expensive one in the shop at the time
which just happened to be $1000 with the added bonus that it had simple motor
drives. It was a 4 inch refractor with very cheap optics and eyepieces. Of
course, I didn't have the luxury of the internet to research my purchase
before-hand because if I did, I would not have wasted my money. It wasn't a
complete waste of time though. The telescope was good enough to give me a taste,
especially after finding Saturn by fluke, and seeing the Orion nebula and
Jupiter. That same year we had a lunar eclipse in Sydney which was awesome to
watch through a telescope.
A word of warning! Don't believe the pictures on the side of the telescope's
packaging are what you are going to see. You will be extremely disappointed and
so will any teenager that you buy it for as a gift. I say teenager because every
time I have been in a telescope shop, I hear some customer asking the sales
people what is a good scope to buy their teenager for Christmas. If you want to
buy for anyone else, first take them to an astronomy venue and give them a look
through a real telescope. This will give you a gauge of their interest and may
save you a lot of money or the possibility of buying a piece of future junk!
On the other hand, sometimes it is good to buy an inferior telescope, just to
teach you that it never pays to skimp in this field. It may also save you from
spending BIG dollars if you find that astronomy is really not your passion. If
you do find that stargazing is going to be a long-time pursuit and if you
can afford to blow all you have, my advice is, DO IT!
A couple of years of enduring the smaller scope saw me coming back from an
overseas work trip, all cashed up from tax-free earnings. I spent what I had and
purchased a large aperture, fully computerised, motor driven and GPS aligned
Schmidt-Cassegrain( Below centre image). Oh my Lord! What a wonderful bit of kit
it is! I couldn't wait to get it out of the box and set it up! Just to see it in
all it's glory in the middle of my lounge room. Using it for the first time was
a little bit daunting, but most computerised telescopes have manuals with them
that give you enough info to get them fired up. Before I knew it, I found that
the telescope was actually teaching me the sky! Sometimes charts don't help if
you have no basis to start from. Just going to one star party of guided tour
will be invaluable in getting you started. I didn't have that luxury so it was
good for me that the telescope had such a database to not only show me named
stars and objects, but heir locations, distances and sizes! Well worth the money
invested.
This I know, the bigger the aperture, the better. Electronics are great but
like the average TV and DVD player, they can do a lot more than you probably
will care to learn to start with. I will spend the next few years getting to
know mine better and still probably wont know it's systems back to front. In
that regard it suppose it will never bore me and I will keep on learning.
Dobsonians (Below right image), are great for their user friendly simplicity and
range of HUGE apertures. I can't speak for refractor telescopes, (Below left
image), because quite frankly, I haven't really used one.
I chose the 11 inch Schmidt-Cassegrain because of its compact portability.
Living in light-polluted Sydney, forced me to drive long-distance for observing
under decent skies. If I was thinking of building my own observatory then, as I
am now, I may have chosen a much larger telescope. This one will do just as well
in a permanent setup anyway. I am dreaming of a 20 inch scope one day. I wish!
If you are a bit of a tinkerer and you love to play with technical stuff,
then have a look at all the things you can attach to a telescope. PC interface,
CCD camera's, video cameras are just a few and there is no end of new and better
technology to add to your ensemble.
Eyepieces and filters
There are a large number of filter and eyepiece combinations for both visual
observing enhancement and astrophotography. Some filters improve contrast
between light and dark so that features stand out in greater detail. Others
filter out such things as ambient or even dangerous light. Solar filters are
available to filter out dangerous light that is capable of damaging your eyes
permanently and can also destroy your telescope's optics in no time at all. Take
time to read up all about SAFETY before viewing the sun!! More on that down the
page.
Laser pointers
These are excellent tools for illustrating the sky to others. When you point
with your finger, everyone has to line up at your shoulder and take turns
looking along your arm and then you still can't be sure they are looking at the
star you are indicating. The laser pointer takes all the guesswork out of it.
All you will hear is "OOOH, AAHH, OH SO THAT'S WHAT IT LOOKS LIKE!" I highly
recommend you purchase one of these. Make sure you get a proper astronomy green
laser, not a cheap red one. There is NO comparison. Be wary of people's eyes,
don't shine it at passing cars or aircraft and try to avoid using it at
astronomy gatherings where there are other telescope users nearby.
Astrophotography
There are so many books and internet resources on astrophotography, that I
hardly know where to begin. Take a good look around and if you can, try before
you buy. I started with a manual SLR, but I found that it's ground screen,
(focus screen) was so course, that it made already faint objects in the
eyepiece, impossible to see in the viewfinder and focus on. In most cases, I
couldn't even see if the object was even in the field of view. Try to buy a
camera with a very fine focus screen. If you go digital SLR, I am told that is
the way to go. Next step is CCD cameras. This sort of advanced photography can
be very complicated and expensive, but they are versatile and turn out some
stunning images. Combine these with photo enhancement software, and you can do a
lot with the images. A CCD chip can be more than twenty times more light
sensitive than photographic film, allowing for greatly reduced exposure times
and greater detail.
The moon
Viewing the moon will temporarily ruin your night vision, so
keep that in mind when you choose to view it. There are filters available for
your eyepieces that can reduce the glare and can improve the contrast and
detail. If you do want to view the moon through a telescope, then a moon with a
shadow on it, i.e. three quarter or less, is best. The shadow line is called the
terminator and it gives excellent contrast between light and dark, showing
crater walls and shadows of all large features. You will observe much better
detail along this line. If you are moving into astrophotography, the moon is an
excellent target to try your first few practice photos on.
Deep-space objects
Deep space objects like nebula and other galaxies are
challenging targets for the beginner. Not only finding them, but focusing on
such small and dim objects can be difficult. I can tell you though, that when
you do find them it is amazing! Once you have located them, it's usually not
hard to find them again. Most of my favourites I have viewed so often, I don't
need to use co-ordinates anymore to find them, I just point the telescope in
that direction and find them by eye. I have had the advantage that my second
telescope was computerised and GPS aligned, so the telescope taught me how to
find everything first!
If you can afford it, buy a good deep space catalogue. Get
one with charts and photographs, so you know where to look and what you are
supposed to be looking at. Most of them will have object Messier numbers,
Caldwell or NGC numbers included. These come in handy when using computerised
equipment because you can just punch in the number on your telescope, and it
will find it automatically and track it.
Comets
The one time I chased a comet, I drove 3 hours after work, out to a felled
pine forest near Bathurst, west of Sydney. Comet Machholz proved to be a worthy
target for a first timer, so when I popped out from under the eastern seaboard's
cloud cover, I set up and waited for dark. I had been tracking the comet in the
night sky from Sydney for about a week, determining it's path past the Pleiades.
Not much to look at in the light pollution for the western suburbs, but once
away from the city, It was awesome. Keep your eye on the astronomy websites for
the latest on comet predictions.
Meteor showers
I haven't had much luck with meteor showers yet. There are meteor showers all
the time, nearly every month. I think the most famous is the Leonids. Meteors
are usually trails of debris particles following a comet's path. On a regular
basis, as these comets pass through the solar system, earth will pass through
the trail. As the various size particles enter the atmosphere, they build up a
high pressure air pocket in front of them. Like the pressurised air in the end
of a bike pump, the air gets hot. Hot enough to bring the debris to such high
temperatures, they can glow, melt, burn out or even explode in a shower of
smaller burning particles like a gravel stone in a hot campfire.
Meteor showers are usually located by giving you what's called the radiant.
If you see a few streaks in the sky through the night and remember the
directions they were traveling, you might think that they are going in all
different directions. In actual fact, you should notice that they all can be
traced back along their trail, to a central point. This is the radiant. Try to
imagine a hose pointed at you, set on spray. As you look at the hose and pass
through the stream, you will see all the water droplets passing you by, fanning
out around you from their originating stream, namely the hose.
You can film meteor showers with a video camera or a web camera. You can be
lucky through a telescope, but it is best to use a camera on a tripod. Use a
wide angle lens, point the field of view at the radiant and set the exposure for
the desired time. If you are in a light polluted area, then this exposure time
should be as short as possible or the film will wash out. As soon as you see a
meteor flash in front of the camera, close the shutter and set it again for
another one. This method also works well on lightning. For example; open shutter
for 20 seconds, if there is a flash of lightning during that time, close the
shutter immediately, then open the shutter for the next 20 seconds or lightning
flash, whichever comes first. Happy hunting!
Solar observing
Solar observing can be very dangerous! Pay respect to all warnings in
this regard! You can cook your instruments and destroy your own eyes. If
you do the latter, say goodbye to astronomy, watching a good movie and life as
you know it in general. Your sight is so precious!
The two types of filters I have experience with, provide very different
viewing.
The standard solar filter looks like tin foil, and covers the front aperture
of your telescope, camera or binoculars. I paid about $60 au from a telescope
shop in Sydney for an A4 size sheet. I cut an off-axis hole in the cover of the
telescope and pasted it over the hole. (See photos below of front and back of
cover). You can buy a pre-fabricated off-axis cover with filter or full
aperture. The sun is made of different layers. This filter takes out about 99.9%
of the harmful light, allowing you to view the photosphere, which is the sun in
visible light and natural colour, (white, image below left.) You can easily see
sunspots, the magnetic anomalies where the magnetic fields interact with the
surface, cooling it by around 1000 degrees. Surface temperature is approximately
6000 degrees Celsius.
The hydrogen Alpha filter, allows you to view the chromosphere. This layer is
above the photosphere and is also hotter than the inner layer. (Below centre
images). Ha filters are extremely expensive but worth it if you look after them.
You will see far greater detail and stunning features, not visible with a
standard filter. Ha filters are also on my wish list.
Satellites
Just before dawn and just after dusk is the best time to view
satellites. The ground you are standing on is in the earths shadow, while the
satellite is high enough to be in sunlight. There are hundreds of satellites up
there but my favourite is the International Space Station. When that baby goes
over, you can't miss it! I find it a very profound moment, looking at that
bright light passing overhead in space, knowing that there is a full time crew
aboard. What a job! A site on the internet called Heavens Above,
http://www.heavens-above.com/ has
some very good info and real time data on what's up , when and where to look.
Once, while looking at the moon through my telescope, I saw a
satellite as a white light move into the field of view then change to a detailed
black silhouette against the white moon backdrop, It was and amazing sight and I
wish I had the camera on at that moment.
Sharing your passion
Remember that while you may love and obsess over your new
hobby, most other people have limited interest in the subject. When sharing the
experience, try to gage your audience fairly. People can get bored with it very
easily. Keep the info informative and not too complicated, but don't insult
their intelligence. Make it fun for everyone, especially the kids. Answer
everyone's questions as best and truthfully that you can. Separate fact from
theory. If you don't know something, its really nice to say "I don't know, but
if you really want to find out, come and see me later and we can try to find
out." If you want a more professional presentation, rehearse it first. Write
down a logical sequence of information, like starting in the middle or the solar
system, and working your way out. Start at the beginning of the created
universe, and travel through to now.
I hope my experiences and advice is helpful and I welcome you to the
universe! It's hard to look at all there is up there and not wonder who designed
it. It's so amazingly complicated, yet so beautifully simple! May you have clear
and dark skies on your observing nights, after all, we do need rain sometimes!
God bless you,
Barry :)
Questions or feedback
If you have any questions regarding this site or you would
like to contact me, email me at
info@asignobservatory.com