General Observing Guide

[Fowad]

Hello Dear friends

In this topic we want to put useful points & experiences about how to observe & what can you do in an observing night to have good observations & results.

So be with us

***************************************
What Can we do to have a great Observation night?!
Find your way around the skies
Understand star co-ordinates and star charts
A guide to seeing and atmospheric transparency
Observing Jupiter's moons
How to… estimate star magnitudes

[gandom]

Fowad:

What Can we do to have a great Observation night?!

I ask all the experienced observers in the forum that please share your informations about this question here and this topic will help us to find out the important notes of being a successful observer!
I myself am not a real experienced one but i share with you what i know about it

First of all,you should specify your purpose of your observation and second, you look at your equipments and third,determine the specifications of the observation point you've chosen exactly and finally, determine the situation of the objects you are supposed to observe and also the moon and other highly annoying bright objects for the specified date!
Very obvious till now!?
I imagine one of these conditions and speak about it! Lets imagine that your aim is targeting some messier objects and you have a normal amateur telescope(from 4 to 12 inches for the Diameter of the main mirror)and you have chosen a place with normal sky(which is empty of clouds and dusts of course!)and there is no moon in sky!
Well,by this conditions,you can notice to these tips to enjoy and learn much more:
First try to adapt your eyes with the dark environment,at least for 20 minutes and then you find the sky full of stars!Shut your eyes down from any other lights except the red light which its low frequency,make the eye much less sensitive to it!A red head lamp is useful because of the freedom of your hands!!:D
If your aim is a little serious and you must manage your time to gather your needed data,you can make some sandwiches for yourself and the rest of the group for dinner!In this way you aren't supposed to spend a special time for dinner and you can have it fast.Also some hot beverages can help you warm up and concentrate on your work.
‌Become sure that you gathered all your needed maps and eyepieces and the other small stuffs that i myself usually forget some of them!!(losing the screw of the mounting of the telescope is a nightmare!be careful!)especially the small stuffs of your Camera if you need one,like filters,mounting stuffs,lenses and etc.If there are some starter observers in the group,a green laser pointer is gonna to be a rescue!!
Depends on your aim,you can choose an appropriate map.for example if you need to make a photo of some fade objects and you have a short time you can use a map like the "observer's sky atlas" and if you are not in rush and don't need details,a map on A3 paper is sufficient!And if you have a laptop,you make it much more easier!
So,what else do you suggest?
I hope you enjoy your observation

**************************************************
gandom:

to have a usefull observing,i think sketching of phenomenas is the best way...I've seen some astronomers that discovered a new planet,new supernova,new star by reviewing their sketch that they draw it before

[Fowad]

to have a usefull observing,i think sketching of phenomenas is the best way...I've seen some astronomers that discovered a new planet,new supernova,new star by reviewing their sketch that they draw it before

exactly!and some times photographing is more effective especialy in the low time situations,or in more advanced researches for the object's positions in the solar system.
I've read an article some times ago in the Astronomy magazine of Iran that was about an astronomer who discovered some supernovas by his own equipments and the point is its sketching activities which easily guided him to discover the alteration of the background stars, sooner than we
observe that supernova by eyes!what a cool job!

[stargazer]

Find your way around the skies

by: Anton Vamplew

This article appeared in Sky at Night Magazine

Image credit: Jon Hicks

To some people these days, the idea of star-hopping seems rather quaint. The idea that you slowly work your way around the sky using only your eyes to identify star after star, steadily building up the patterns of the constellations, surely belongs to a bygone age.


After all, today we have Go-To telescopes that can take you to any star or fuzzy nebula instantly. There you go – no knowledge of the sky necessary. Go-To telescopes certainly have their place.

For example, if you want to show the wonders of the night sky to a group of friends, it’s just a case of pressing some buttons and hey presto: deep-sky object after deep-sky object appears as if by magic. Certainly, with their computer databases of where each galaxy and nebula is located, Go-To telescopes are great for finding some of the more challenging, faint, fuzzy blobs.

However, there is something very rewarding in having a mental map of the stars, so that you
can glance up with confidence and point out Leo, Gemini or Ursa Major to whoever is within earshot. And that’s before you’ve pointed out the planets, which are sure to increase anyone’s fascination in the night sky.

It’s true to say that few people know their way around the night sky well enough. The only way of being able to gain this useful and entertaining knowledge is to learn the sky – and it is by star-hopping that you learn.

To be continued.....

[رخساره روشنی]

as my friends said, first of all we should chose what we want to observe , it means we should manage our observing night but chosing a good place for passing our observing night is very important , I know its importance because I have experienced a bad situation when i was out of the city for observing. the place I've chosen to observe was full of dangerous animals such as dogs and jackals. I was very scared and couldn't observe any more.

[stargazer]

A Universe to discover

Star-hopping really is fascinating. Not only are you recognising the patterns of constellations, you’re also learning about star distances, star colours, ages and names.

You’ll find that the whole of the night sky is an amazing mixture of space, time, history, science and world cultures. It’ll lead you off on all sorts of paths and you’ll learn things that will amaze others. Not to mention the basic reason – you’ll know what you’re looking at.

Now, you don’t need any optical instruments to begin star-hopping, but it does help to have a few things handy to make your evenings more enjoyable.

Firstly, let’s deal with the comfort aspect.Even in the summer, it will probably get chilly – at the very least – so wrap up warm.

Then, to get as comfortable as possible, set up a deck chair or sun-lounger – maybe we should call it a star-lounger in this case.

Just before you pop outside to try some real star-hopping, there are a couple of final useful things to have with you: a star chart or atlas, plus a red torch to see the charts, and also where you’re going, without ruining your night vision. And don’t forget a flask of tea and a few biscuits for when you fancy a break.

If you’re new to star-hopping, position your star-lounger north-south and sit with your feet pointing north. This will put you in an ideal position to see several key star-hopping points: the Plough, the North Star and the constellation of Cassiopeia as they’re all around the north part of the sky.

Why not practise star-hopping using the example shown below? Remember, take it easy, and you’ll be finding your way around the sky in no time.

to be continued.......

[stargazer]

Star-hop from the Plough to Cassiopeia



1 Find the Plough

The Plough is a shape or ‘asterism’ found in the constellation of Ursa Major, the Great Bear. It’s a good place to start because it’s a recognisable shape. It’s also close to the north pole of the sky, meaning it’s always visible in the night sky.



2 Move from the Plough to the Pole Star

The two right-hand stars of the Plough are known as the Pointers. Extend an imaginary line between them and out of the Plough and they’ll point to the Pole Star, which is also called Polaris.



3 Trace the shape of Ursa Minor

The Pole Star is the main star of the constellation Ursa Minor, the Little Bear. This is shaped like a smaller, fainter version of the Plough and you can trace its form arching off from Polaris. Well done, you’ve found a new constellation.



4 Move on to Cassiopeia

Continue on in the same direction you took from the Plough to Polaris, for around the same distance again. You’ll find the distinctive ‘W’ of stars that make up the constellation of Cassiopeia. That’s it, a successful star-hopping session.

to be continued....

[stargazer]

Hopping with binoculars

Binoculars provide another way to star-hop. The trouble is, when you look through them it’s easy to lose your bearings because you’re only looking at a small piece of sky. A good trick is to work out how much of the sky your binoculars show you (their field of view).

To do this, take a look at the Plough, noting which stars are at the very edge of your binoculars’ field of view. Now find these stars on a starchart and make a ring out of wire and place it around them.

This ring is the field of view of your binoculars at the right scale to use on your starchart.You can then move your wire ring around the chart to plan each step of your star-hop and know in advance what the view should look like.

Try aiming for the Double Cluster in Perseus – it’s a great target through binoculars and it’s very close to Cassiopeia

[stargazer]

Understand star co-ordinates and star charts

by: Anton Vamplew

This article appeared in Sky at Night Magazine

When those early pioneers of science, the ancient Greeks, looked up at the night sky, they described it simply as it was seen. They imagined that the Earth was fixed at the centre of things, with the Solar System orbiting around us.

Beyond was the night sky, which they imagined as a sphere with the stars projected on the inside. This became known as the celestial sphere. It was the starting point for mapping the stars.

Even though we now know much, much more about our planet’s place in space today, we’ve held onto the celestial sphere because it’s such a useful way of thinking about the sky. Indeed, it even makes it possible to put all that starry-sky vastness onto a flat sheet of paper and make a starchart, with which you can find your way around the sky.

And just as latitude and longitude are used to find locations on the globe of Earth, the same idea works up there with the stars. The celestial sphere also has a grid system, which is simply a projection of latitude and longitude up onto this imaginary sphere.

The only difference with this celestial grid is that it has different names. Latitude – the lines that run around the Earth parallel to the Equator and give the north-south location– is called declination, while longitude – the lines that run up and down through the north and south poles and give the east-west location – is called right ascension.

to be continued...

[stargazer]

Getting your bearings

Declination, often shortened to dec., is quite simple to get your head around because it uses the same units as latitude, degrees (°) and minutes (’), along with the smaller arcsecond (”). The ‘arc’ here is used to make it clear that this is a measurement of distance and not of time.

There are 60 minutes in one degree and, not surprisingly, 60 arcseconds in one (arc)minute. Degrees of declination start from the zero marker on the starry version of our equator, known as thecelestial equator.

If you move into the northern sky hemisphere you’ll find a ‘+’ symbol is used before the figures, whereas you’d put a ‘–’ symbol first to show that the degrees and minutes are located in the southern hemisphere.

Right ascension, or RA for short, is slightly more complicated because it uses hours (h), minutes (m) and seconds (s) as units. One hour of RA is the same as 15º of longitude – that’s movement left or right. Time is used as the unit here instead of angles because it represents the Earth’s rotation: in one hour the sky turns 15°. You’ll see this all adds up perfectly for one day and night, or 24 hours worth of rotation: we have 24 hours x 15 degrees, which equals 360° and one complete rotation of the Earth.

Here’s how we’d write the position of the brightest star in The Plough, Dubhe: RA 11h 04m 15s, Dec. +61° 42’ 03”. You’ll notice that RA comes first (it always does) and that there’s a ‘+’ sign in front of the Dec. number, showing that the position of the star is in the northern hemisphere. With the position of a star written like this, you’ll be able to find it on a chart (see photo below).

to be continued...