What targets to observe? How I plan....
Good evening!
Winter has most certainly arrived in Ross Vegas, and the
cold dark nights have imposed themselves upon us for what I hope will be an
excellent winter of observing. The
darker evenings give us working mortals more chance to set up a scope for a
session, and still get to bed as a reasonable time on a school night. Providing the weather plays ball of course!
Recently, I’ve been speaking to several people in
reference to observing sessions, and how I decide what to observe in a
session. Of course, there are a vast
amount of targets available to go after.
Some of them are arranged in catalogues, such as the famous Messier
catalogue, and then there are the planetary targets in our solar system and the
various moons associated with them. All
these things provide a vast list of things to go at.
In this blog entry, I will attempt to describe how I plan
my observing sessions and how I have found to get the best out of them. I don’t think that there is a definitive
right or wrong way to go about this and in my short time as an amateur observer
and stargazer, I’m always on the lookout for help and advice from other members
of the astronomy community who have a lifetime more experience than me. So, let’s begin.
Observing sessions for me usually last in the 2 to 3 hour
range, longer on weekends. As well as
time and visibility, I also find that the temperature and dew can restrict the
time I spend at the eyepiece. Without
the various dew shields and straps that can be bought for telescopes, after a
while, dew and frost will ultimately win and often dictates the end of the
session. So, it’s important to be
prepared.
My preparation for a session usually starts on the days
leading up to the time when I go out.
The first consideration I make is the time of year. As any budding enthusiast will tell you, the
time of year will determine what is available in the night sky to be observed
due to the seasonal skies around us. Any
good star atlas, or chart will be able to tell you what is visible at different
times of the night for any period of the year.
I also refer to forums such as Stargazers Lounge, magazines such as
Astronomy Now, and The Sky At Night and TV programmes to find out about any
unusual or rare objects that can be observed.
A recent example of such an object was C2/2014 E2 Jacques. Usually, the rare objects will take some sort
of precedence on the plan.
The next consideration I make, or rather, the next
decision I make, tends to be to choose a specific area of the sky to work with
for the evening. Usually, I will chose a specific constellation or two, or
depending on the moon phase, plan a lunar observing session. I have to bear in mind where my observing is
going to be completed from. For
instance, if I go back yard observing, then there are several impediments to my
view of the night sky such as buildings.
If I am to observe from somewhere else, I will usually have an idea of
the views to horizons and take these into consideration.
Now is the time to reach for a more detailed star atlas,
or programme such as Stellarium. It’s
time to do a bit of research. Like most
people, when you have used a specific telescope for any amount of time, you get
to know its limiting factors, especially its limiting magnitude in given
conditions. I refer to an atlas and pick
out objects that I think that I will be able to view with my scope. This can mean a bit of time online too, in
order to get the correct magnitudes.
Time can be quite precious, so I don’t really want to be stuck trying to
find an object with a magnitude so dim that it is beyond the capability of my
scope and eyepieces. When lunar
observing, knowing what parts of the lunar surface are going to be visible is
important, as well as the times for moonrise and moonset.
Usually, I’ll note down around 6 to 8 targets of varying
magnitude to give me a good spread of targets to look for. I will also try to familiarise myself with
their respective locations amongst the constellations to make navigating to
them an easier task.
I find that by keeping a potential target list at this
sort of length for an evening’s observing is ample to get on with. When I first started, I used to find myself
rushing around the sky trying to seek out as many targets as I possibly
could. They are exciting times indeed,
but I have since slowed my observing pace down a little. I now spend much more time on an individual
target and allow myself the opportunity to explore it fully, to tease out as
much detail as possible using a selection of eyepieces. If my research before the session suggests
that a target is better viewed with a specific filter, then I will make sure I
take the time to use that filter if I have it and compare the images I see.
I have learned that it isn’t important to achieve everything
on the intended list for the night. If I
only end up seeing 1, 2 or 3 targets on the list for that session, then so be it. There will always be another time to go back
and tick them off again at a later date.
I like to record what I see and when. Indeed, a large part of this blog is given
over to my observational records. I also
have a field notebook which comes outside with me, and is with me when I plan
what to see. It’s also got plenty of
scribbles and notes on anything astronomy related that I might one day want to
refer back to. And finally, I also have
a book solely for observations. As much
as I use and embrace IT, computers and the internet, there is no guarantee that
all my observing records are always going to be available to me online for the
rest of my days.
And finally, another lesson that I’ve learnt is that you
soon get some favourite targets that you find yourself drawn to time and again. Typically, things like M31, the Andromeda
Galaxy, the Double Cluster in Perseus and M57, the Ring Nebula in Lyra. Not to mention the giant planets Saturn and
Jupiter. I’m drawn to these for a
reason, whatever that might be. It’s
important for whatever that reason might be, that I spend time re-visiting
them. As they are favourites, they tend
to be easy to locate the 4th, 8th 10th or
whatever time, and it’s always a nice way to end a session by re-visiting one,
or some of these targets.
So, in brief then, my top tips for planning an observing
session:
1. Research
what’s available for the time of year.
2. Research
any special or rare targets observable at the time.
3. Consider
the observing site you intend to use and account for any viewing restrictions
in place.
4. Focus
on one or two constellations, a lunar, or a planetary session.
5. List
between 6 and 8 achievable targets in your chosen area.
6. Take
your time on each target and experiment with all available options to get the
best views.
7. Don’t
rush to tick off all the targets in a single session. If you miss some out, they will usually be
around next time.
8. Revisit
at least one favourite from previous sessions.
9. Note
the observations and record.
10. If
there targets remaining on the list at the end of the session, use them on the
next target list.
Thanks for ready,
Clear skies,
MMM
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