Observation Gear

Stumbled upon a really useful article on my Astronomy reader – written by the CuriousAstronomer…every “telescope-user-beginner” has got to read it! And voila, my first reblog! 😉
These are really the essentials you’ve got to know when collimating your scope. If you need to collimate the secondary mirror of a reflector, you’d need to adjust the bolts on the spider to get the mirror aligned to the focuser (you’d need a sighting tube for this)…but mostly you’d only need to adjust the primary (the rear) mirror – and for that, just tweak the screws on it, till you get an out-of-focus star that looks like a doughnut :)) (pic is below). Here as well, a sighting tube or a laser collimator come in handy (though they’re not altogether necessary).

Heyyy thanks Rhodri for posting this up – been great meeting you! — who knew the world was so small!

thecuriousastronomer

I was on the BBC last week recording an interview which will go out this week. One of the topics discussed (in addiition to how to take a pee in the dark) was how to collimate a telescope.

Two types of telescopes – Refracting and Reflecting

There are two basic types of telescopes, refracting telescopes (which use lenses) and reflecting telescopes (which use mirrors). Either type of telescope can become mis-aligned, usually through the telescope being knocked. Putting it back into alignment (technically called collimation) is not a difficult process, and should be the kind of thing anyone can do with a little patience.

There are many expensive gadgets available to help you align a telescope, but none of them is really necessary. The easiest way to do it is to simply point the telescope at a star and then de-focus the image. You will end up with a…

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Astronomy gear that tempt me ohhh so bad.

After a year and a half of OptCorp and Cloudynight/Astronomyforum reviews, here’s what I’ve come up with.

My “Must Have” or rather ‘Futilely Desire” list:

1. A Barlow (would love a Televue 2″ 2x Powermate)
2. A Wide Field Eyepiece ( aVixen 1.25″ 40mm NLV seem like the best bet! – would love the 2″ 50mm, if not for the extra 100 dollars!)
3. A Devoted Planetary Eyepiece (William Optics anyone?)
4.A Stellarvue (yes you heard it!) 10x60mm Finderscope – that’d also serve as a mini portable refractor for the planets, with its 2″ focuser, and 1.25″ adapter.
5. A pair of binoculars (less than 70mm aperture, so I wouldnt need a tripod) ….or should I get a monocular? Waterproofing is great as well! Any recommendations?
6. A Baader Planetarium Moon & SkyGlow filter.

And yes, you must know my scope and viewing conditions.
I have a 10″ Dobsonian Skywatcher.
And the basic set of accessories that come with it, a 24mm and a 10mm Plossl.
Heavy light pollution and haze from my side. Viewing is mostly limited to planets.
But occasionally the skies are clear – and I get to catch the brighter nebular. Still a dream of mine to catch the Horsehead Nebula someday.
Thinking of getting a wild-field eyepiece to starhop. Do you think it’ll work? There really isn’t much point in starhopping with a finderscope, as the stars are too dim from where I’m at.

So let me know what’s your favourite pick? And if you’ve got any other suggestions, that’ll be great!

Till then, cheers!

ps. This is THE best article I’ve read on planetary eyepieces. Learnt so much from it – and it wasn’t a tad bit boring at all!
6mm Lunar/Planetary Eyepiece Comparison – by Bill Paolini

Categories: Amateur Astronomy, Observation Gear, Uncategorized | Tags: , , , , , , , | Leave a comment

Clear Skies!

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It’s 4 AM and Jupiter, Mars, and Orion are right above my balcony. Whatta treat!!

Been such a long time since we’ve had clear skies and when it was clear last night, I just had to take the Dob out! – despite loosing much sleep…with upcoming exams, oh noo!

Btw, Jupiter doesn’t look nearly like the picture I took…after 1/2 and hour struggling to get (and focus) it into the field of view of the camera. You’ll actually be able to see its orange rings with a 24mm Plossl, and swirls on it with a 10 mm Plossl eyepiece! Mars was orange as usual. And the Nebula with its Trapezium, frozen in time. Bout time I get some filters – for some colour with the nebula and for better definition of the Great Red Spot. And I reallyyyy wanna see the Horsehead nebula on Orion!

Any thoughts on good filters? I’m thinking Baader’s Moon and SkyGlow filter – seems like a good all around filter for both sodium vapour wavelengths (light pollution) and for contrast.

Clear skies!

Categories: Amateur Astronomy, Misc, Observation Gear, Solar System | Tags: , , , , , , , , | 2 Comments

StarHopping – Old Skool Style

So, if you don’t have a PushTo, GoTo or a Telrad (like myself), this is whatcha gonna need for some old-skool style star-hopping.

Gear

Star Chart

Here’s a link to a free downloadable version which I’ve used for my observation nights with my club: SFA Star Chart. Star Charts map constellations, nebulae and galaxies, and they sometimes even indicate brightness! So, before you start observing, you’ll need a star chart to know what’s up in the sky tonight, decide which object to hunt for and use the pattern of stars to guide you there. Without star-hopping, locating an object is like looking for a needle in a haystack – especially if your eyepiece has a narrow field of view and a short focal length – talk about tunnel vision!

Hands

A Compass

Instructions

The trick is to imagine your star chart as a sphere encapsulating Earth.

From the Equatorial Region

Check your Star Chart and lookout for today’s date (its on the horizontal axis). If you imagine a vertical line through the point which marks the date, that would be the view of the skies at the Celestial Meridien at 8 pm. Then on, just minus or add the time of your viewing to the Meridien (at 8 pm) and shift your focus (the imaginary vertical line) on the map – basically, aligning the Celestial Meridien to the current time. So, if you’re observing at 11pm, you would need to add 3 hours (11-8=3) to the 8pm Meridien, which means, looking 3 hours to the left of the imaginary 8pm Meridien line on the map. if you’re observing at say 7 pm, look an hour (8-7=1) to the right of the 8pm Meridien. Once you’ve approximated your vertical axis, look up to the skies and align it with what you see.

Now if you wanna see the Eastern sky, align yourself to face East – here’s where the compass comes in. Look at the left of the vertical line which matches your time of viewing and date. And if you want to see the Western sky, face West and look at the right of the imaginary line. You see, as Earth rotates, you’ll see new stars emerging on your East and other stars falling under the Western horizon.

It all may sound quite confusing. So, back to basics, imagine your chart as a sphere wrapped around Earth, and remember how Earth’s rotation makes the sky look like its moving. Check out: Why Stars Move

Next up, is using your hands. Once, you’ve located what you see on the chart, to hop to the right star, you’ll need to measure. On the chart, are “latitude lines” 10 degrees apart. How on earth would you know what’s 10 degrees apart in the sky. Well, make a fist and point it up to the sky, the length of a fist measures 10 degrees in the sky. The thumb, about 5 degrees. And if you open you hand as wide as possible, from the tip of the little finger to the thumb’s tip, 25 degrees.

Now, you’re all set!

Zoomed in Star Chart

ps. What’s the Celestial Meridien?It’s a circle the passes through the north and south celestial poles, the zenith and nadir. Read: Measuring the Sky to find out more.

Categories: Amateur Astronomy, Observation Gear, Observation Tips, Stars | Tags: , , , , , , , , | 6 Comments

Why Stars Move

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If you observe the skies at night long enough, you’ll realise that the stars move. You’ll see some constellations disappearing below the horizon and new ones appearing on the other side all in one night. Just like the way the sun and moon rises and sets. Well, It’s not the movement of the stars that causes them to rise and set on the horizon, but rather Earth’s rotation on its axis, around the sun.

Here’s a pic which summarises the rotation of Earth. It spins on its axis which is tilted 23.5 degrees to the perpendicular of its orbit around the sun (the Ecliptic). So, during the course of one Earth rotation (which is one day), it’s Ecliptic appears to shift north and south of the Celestial Equator at a tilt of 23.5 degrees.

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Source: Massey, S. and Quirk, S. 2010. Atlas of the Southern Night Sky Second Edition. Australia: New Holland Publishers

We see stars when Earth faces away from then Sun. Earth is always spinning; Throughout the night, some stars will disappear below the horizon on the West and new ones will appear on the Eastern horizon. And since Earth makes a complete orbital around the sun in a year as it travels on its ecliptic, we journey around the sun seeing all the different constellations in our skies as we, like passengers, are transported by our very own spaceship, Earth.

Categories: Observation Gear, Stars | Tags: , , , , , , , , , , | 1 Comment

SkEye Planetarium App

My favourite planetarium App for Android mobiles: SkEye!

Why I absolutely love this app you ask?

1.  It’s calibrates to the section of the sky you’re pointing almost instantly. I have the GoSkyWatch app too but it’s does not calibrate as fast as SkEye when you’re moving your mobile and pointing it to different parts of the sky.

2. It has a search function that guides you (with a bullseye reticle) to point your mobile and zoom in onto the interstellar object you’re looking for.

3. Plus, it has a huge database of deep sky objects, Messiers and NGCs. Way more than I could ever hope to observe from the suburbs with moderate light pollution levels, in which I live in, through my 10″ scope.

4. It can be used as a PUSHTO Guide on your telescope optical tube assembly. All you’ve got to do is attach your mobile to your scope, align the app’s map to what you’re observing and voila, you now have your very own tracking system!

5. All these features come free!

For detailed instructions, visit: SkEye, Planetarium and PUSHTO Guide for Android.
Visit the SkEye’s official site at:  http://lavadip.com/skeye/index.html

Categories: Amateur Astronomy, Observation Gear, Observation Tips | Tags: , , , , , , , , , , | 2 Comments

Review: 10″ SkyWatcher Collapsible Dobsonian

Here’s my first ever telescope! Early last year, my parents promised me a gift for doing well in my national exams. So, since then, I’ve been on a hunt for my first ever telescope.  I did loads of research before buying it (as it wasn’t going to be cheap!). In the end, I ended up learning so much:  the differences between a reflector, a cassegrain, a refractor; the importance of aperture, focal length and focal ratio; which eyepieces and filters work best; collimation; portability; mirror quality (pyrex or perspex) and coatings. In the end, I chose a dobsonian (a Newtonian reflector minus a tripod but with a Lazy Susan base instead) as it provided the most aperture for the least cost (as a tripod stand isn’t needed).  “Aperture fever” I must say!

And thank god for that as I’ve got too see things like the Trapezium Nebula and NGC 1999 (a small reflection nebula) through it! Observing from my light-polluted balcony, I don’t think I would have got to see as much using a smaller aperture (albeit more portable) scope.

This site proved invaluable in the study of observational gear: http://www.cloudynights.com/

Here’s a link to a dilemma I faced when having to choose between an Orion XT 10 and A Skywatcher Collapsible Dob. http://www.astronomyforum.net/dobsonian-telescopes-forum/113499-optical-quality-orion-xt10-vs-skywatcher-10-collapsible-dob.html

A picture of my sister and I collimating the scope. Yes we used sunglasses to protect our eyes from laser light from a Saxon Laser Collimator! Though I don’t think it helped much as I later read that we would need special glasses for laser protection. Word of advice, point your dob at a wall when using a laser collimator, so the reflected laser beam (from the primary mirror) dosn’t aim straight at your eyes and burn cells in them.

Image Credits: Vasanthi Vijaya

I was initially worried that nudging the tube (as it’s not equipped with a tracking device) to keep track of an interstellar object in the field of view would be troublesome, but worry not, it’s not as bad as it sounds.  In fact, you barely even realize you’re moving the tube as you’ll probably be too engrossed with whatever you’re looking at (like myself).

Images are really clear too; the first object we saw through it was the moon on a clear night and it look like a giant crystal of ice. It was just breathtaking! The craters were really well defined and sharp. You’ll have to see it for yourself to believe how beautiful it looked!

And guess what, the collimation holds really well too. I’ve only collimated it once when I first bought it. Each time I observe, I’ve got to carry it out to the balcony (about 15 feet away) with the help of my dad. Despite all the bumping around when transporting the scope back and forth between my dining room and the balcony (which has been going on for almost 9 months now), I’ve never had to collimate again!

A scope highly recommended!

Let me know if you have any questions about this scope, I’ll be glad to help.

Categories: Observation Gear | Tags: , , , , , , , , | 6 Comments

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