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Repost: So you got a new telescope for the holidays – A new telescope owner’s primer

This is a repost of our usual post-holiday telescope primer for new telescope owners:

So you got a new telescope for the holidays: A Quick Primer for new telescope users.

Be it X-mas, Hannukah, Kwanza, Solstice or Giftmas this is the season for getting telescopes as gifts. Sadly, many of these scopes might be rushed into usage and some critical steps might be 016skipped. This can result in a frustrating experience for a budding young astronomer who may give up their new hobby prematurely. This can be avoided if you only take the time and a few precautions to make certain you get the baby steps out of the way without too much tripping and falling.

1) Do as much as you can during daytime first!

I can’t stress this too much. Many folks assume they can assemble their telescope right out of the box at their chosen viewing spot – in the dark. Suffice it to say this is not a good idea. Assembling out of the box at the viewing site might be an extreme example but you should certainly try working your scope and getting the ‘feel’ for it during the daytime as much as possible. Take your telescope outside during the daytime and point it at a nearby tree or other object (the object should be at least 1/4 mile away). Use this object to align the finder scope (see below) as well as test how the eyepiece focuses. Try changing your eyepieces between the low and high powered ones to see how that works as well. Move the telescope in large movements as well as using the slow motion controls as well. When you do these things in the daylight you can get a much better feel for how they should work than if you try them at night. Also if you drop an eyepiece or loosen a screw you have a decent chance to find it. Get your mistakes out of the way when the sun is up.

2) Assemble your telescope properly

This should go without saying, but it is amazing how many folks skip a few steps or don’t attach parts, or don’t read the instructions properly. We’ve seen telescopes in for “repairs” just after the holidays that were just put together wrong, or some critical final steps were ignored (slow motion controls not attached, counterweights not placed). Most of the time, there are very few non-critical elements of a telescope’s construction. So be sure to follow the assembly procedure carefully. Allow yourself a couple of hours as well (maybe three hours for certain models of dobsonian telescopes) for the assembly. Don’t assume you can just put it together a 1/2 hour before you plan to head out and view.

3) Align your finder scope. Align your finder scope! ALIGN YOUR FINDER SCOPE!

Get the point? Many folks ignore this step until the last minute and we can tell you that trying to work a telescope without an aligned finger is very,very, very hard. Even the lower 084magnifications on a short focal length telescope only see a little under 1 arc degree of the sky. This is a tiny portion of the sky so hoping to find an object with just the eyepiece is really hard to do. There is a reason why almost all telescopes come with a finder scope. So make sure to align it (During the daytime per suggestion #1) . If your telescope comes with a red-dot finder instead of an optical finder scope, be certain to carefully align that as well during the daytime – and don’t forget to switch it off! A dead battery in a red dot finder is nobody’s friend.

4) Did you get an Equatorial mount? Figure out how it moves!

An equatorial mount has some great advantages over a regular altazimuth (altitude-azimuth) mount. It can track, be motorized, and the larger ones can even be used with setting circles to locate objects in the night sky. But these are only true if you take advantage of the equatorial mount’s features and set it up properly. During the daytime (suggestion #1 again!) try a rudimentary set-up of the equatorial mount. This does not have to be super accurate as some telescope’s instruction manuals may require, just enough to get mostly accurate tracking for a little while. Perhaps more importantly, get a feel for how the telescope moves – you are used to moving things in an up/down left/right fashion. Now you need to get used to moving the telescope in declination and right ascension. Try moving the telescope from one target to another using the mount properly during the daytime to get a better sense of it. One thing to keep in mind is that the counterweight is there for a reason – it shouldn’t be pointing down all the time.

If you have a larger Equatorial mount keep in mind that you can use the setting circles to help find objects in the night sky with the help of a star atlas. But this means you have to learn to use it. Read your instruction manual carefully. You might also consider downloading a Sidereal Time app for you smartphone. You’ll see why once you figure out the details of using your Equatorial mount.

5) Choose your first targets wisely!

Many folks go out with their telescope and just point it at the brightest thing in the sky. This is fine if the brightest object is a planet or the Moon, as there is lots to see. But very often at this time of year the planets might not be out until very late and the brightest thing in the sky is the star Sirius. Problem is, Sirius is just a star and stars appear as just a point of light even when magnified through your telescope. This can be a very boring target and can be disappointing if it is the only bright object. So make certain before you go out for your first night’s viewing that you know what will be up! Most telescopes these days come with some rudimentary planetarium software that can show you what the sky will be like on any night. Failing that there are online websites that do the same thing (sometimes better). Planispheres can also be used, and if you have a Smartphone or pad you should download a planetarium app like Google Sky (its free). Depending on what time of the month it is, the Moon may not be up during evening hours. Since we suggest the Moon as a great first target for your telescope you might want to wait for it. Failing that, try to look for the brighter planets.

6) Got a computerized telescope? Take advantage of free smartphone apps to make it much easier to set up!

We’ve been kind of ‘meh’ about computerized telescopes in the past, and are still a bit wary of a telescope where 70% of the cost is in the computer andGoogleSky motors and not the optics. But we have softened a bit since they have become a bit easier to use – and not because they changed, but rather our phones did.

Computerized telescope makers kind of make it seem like a computer means your telescope will magically find things in the night sky. All you need to do is toss it into your yard and enjoy the viewing. But that is not how they work. To set up the telescope’s computer you need to point it at two named stars so it can calculate where everything else in the night sky is located. This used to mean that to set up the telescope you had to have good knowledge of the night sky to find those stars -which kind of defeated the purpose.

But now smartphones are ubiquitous these days and there are plenty of planetarium apps out there for free that will help you identify those stars. Smartphone planetarium apps are not super-accurate (they can be off by as much as an hour)  but they will help you spot and identify bright stars that you need to aim your telescope at to orient the computer.  This makes the computer orientation much easier to do than trying to learn to use a planisphere or star map on the fly.

7) Learn, learn learn!

There’s a host of information for astronomy newbies on the internet and in books. Amateur astronomers are very keen on sharing their knowledge and experience with you. Check out the major magazines online websites such as Sky & Telescope or Astronomy. There are a zillion astronomy websites with forums as well you might wish to peruse. Even on this blog we have a collection of Telescope Tips you should check out for helpful advice. Also consider joining or at least contacting your local astronomy club – you can find all kinds of help from them, as well as many other benefits from membership (such as loaner equipment).

If your first night with your telescope is a good one, then you’ll have a much better time with the hobby. But always remember a little planning goes a long way!

Happy New Year!

Interested in buying telescopes?

www.spectrum-scientifics.com

Telescope Tips: Spherical Mirror vs. Parabolic Mirror.

This is actually an issue that may be affecting more and more people buying their first telescope. A few years ago multiple sellers 013on eBay flooded the market with cheap no-name reflecting telescopes that had short tubes. There’s nothing inherently wrong with short tube telescopes, in fact they can be great for beginners as they tend to have wider fields of view. ( Because Short Tubes = Lower mangifications = Wider fields of view = easier to find objects in the night sky!).

Unfortunately all those cheap telescopes with short tubes had a big shortcoming – they all had Spherical Mirrors in them instead of the more called-for Parabolic Mirrors.

(more…)

The Art of Surviving an Astronomy Session

So you got yourself a new telescope and it is a clear night out. Time to grab the new telescope and bring it outside, right? Hold on there; as many new astronomers have discovered, an observing session isn’t as simple as when you go outside in the winter/early spring to put out the trash. There are several things you should probably prepare before you go out for a night of observing.

DRESSING FOR THE NIGHT WEATHER

Far, far too many folks dress for the daytime weather. This can be a problem for you if the daytime was a happy 78 degrees and then drops as the sun goes down into the 60’s.  Many an observing session has been ended prematurely because the astronomer forgot to wear a sweater.

For colder weather, it is 670px-Dress-for-the-Cold-Step-1-Version-2wise to dress in layers.  This way you can adjust your level of warmth as the night goes on. The only trouble with dressing in layers is that you need to get dressed indoors where it is warm and putting on multiple layers is a bit more complex than just tossing on a jacket. I have had sessions where I dressed for warmth and then had something delay my exiting the house, the result being me sweating up a storm before I got outside.

PREPPING THE AREA AROUND THE TELESCOPEfoldingtable

Even if you only have the eyepieces that came with your telescope and a star chart it might not be a bad idea to have somewhere to put these items down. A simply folding aluminum table can help a lot without being too much of a burden. You might also consider some kind of carrying case for the eyepieces. Keeping them in your pocket can be hard on the glass and coatings in the long run.

KNOW WHAT YOU WANT TO VIEW IN ADVANCE…OR DON’T

2241largeWell before you go out, you should decide what you would like to observe that night, or if you just want to aim the telescope around and see what you can find. The latter can be lots of fun, but it can also get old pretty fast if you don’t find anything of interest. The former does require some planning, so be sure to check your planisphere, planetarium program or other astronomical assistant before going out.

HAVE FUN!

Far too many folks turn hobbies into chores – Astronomy is by no means unique in this regard. Doing some work in any hobby to get the most out of it is to be expected, but turning it into a huge burden can make you burn out on astronomy.

www.spectrum-scientifics.com

 

 

 

 

 

REPOST: So you got a new telescope for the holidays – A Quick Primer for new telescope users.

Be it X-mas, Hannukah, Kwanza, Solstice or Giftmas this is the season for getting telescopes as gifts. Sadly, many of these scopes might be rushed into usage and some critical steps might be 016skipped. This can result in a frustrating experience for a budding young astronomer who may give up their new hobby prematurely. This can be avoided if you only take the time and a few precautions to make certain you get the baby steps out of the way without too much tripping and falling.

1) Do as much as you can during daytime first!

I can’t stress this too much. Many folks assume they can assemble their telescope right out of the box at their chosen viewing spot – in the dark. Suffice it to say this is not a good idea. Assembling out of the box at the viewing site might be an extreme example but you should certainly try working your scope and getting the ‘feel’ for it during the daytime as much as possible. Take your telescope outside during the daytime and point it at a nearby tree or other object (the object should be at least 1/4 mile away). Use this object to align the finder scope (see below) as well as test how the eyepiece focuses. Try changing your eyepieces between the low and high powered ones to see how that works as well. Move the telescope in large movements as well as using the slow motion controls as well. When you do these things in the daylight you can get a much better feel for how they should work than if you try them at night. Also if you drop an eyepiece or loosen a screw you have a decent chance to find it. Get your mistakes out of the way when the sun is up.

2) Assemble your telescope properly

This should go without saying, but it is amazing how many folks skip a few steps or don’t attach parts, or don’t read the instructions properly. We’ve seen telescopes in for “repairs” just after the holidays that were just put together wrong, or some critical final steps were ignored (slow motion controls not attached, counterweights not placed). Most of the time, there are very few non-critical elements of a telescope’s construction. So be sure to follow the assembly procedure carefully. Allow yourself a couple of hours as well (maybe three hours for certain models of dobsonian telescopes) for the assembly. Don’t assume you can just put it together a 1/2 hour before you plan to head out and view.

3) Align your finder scope. Align your finder scope! ALIGN YOUR FINDER SCOPE!

Get the point? Many folks ignore this step until the last minute and we can tell you that trying to work a telescope without an aligned finger is very,very, very hard. Even the lower 084magnifications on a short focal length telescope only see a little under 1 arc degree of the sky. This is a tiny portion of the sky so hoping to find an object with just the eyepiece is really hard to do. There is a reason why almost all telescopes come with a finder scope. So make sure to align it (During the daytime per suggestion #1) . If your telescope comes with a red-dot finder instead of an optical finder scope, be certain to carefully align that as well during the daytime – and don’t forget to switch it off! A dead battery in a red dot finder is nobody’s friend.

4) Did you get an Equatorial mount? Figure out how it moves!

An equatorial mount has some great advantages over a regular altazimuth (altitude-azimuth) mount. It can track, be motorized, and the larger ones can even be used with setting circles to locate objects in the night sky. But these are only true if you take advantage of the equatorial mount’s features and set it up properly. During the daytime (suggestion #1 again!) try a rudimentary set-up of the equatorial mount. This does not have to be super accurate as some telescope’s instruction manuals may require, just enough to get mostly accurate tracking for a little while. Perhaps more importantly, get a feel for how the telescope moves – you are used to moving things in an up/down left/right fashion. Now you need to get used to moving the telescope in declination and right ascension. Try moving the telescope from one target to another using the mount properly during the daytime to get a better sense of it. One thing to keep in mind is that the counterweight is there for a reason – it shouldn’t be pointing down all the time.

5) Choose your first targets wisely!

Many folks go out with their telescope and just point it at the brightest thing in the sky. This is fine if the brightest object is a planet or the Moon, as there is lots to see. But very often at this time of year the planets might not be out until very late and the brightest thing in the sky is the star Sirius. Problem is, Sirius is just a star and stars appear as just a point of light even when magnified through your telescope. This can be a very boring target and can be disappointing if it is the only bright object. So make certain before you go out for your first night’s viewing that you know what will be up! Most telescopes these days come with some rudimentary planetarium software that can show you what the sky will be like on any night. Failing that there are online websites that do the same thing (sometimes better). Planispheres can also be used, and if you have a Smartphone or pad you should download a planetarium app like Google Sky (its free). Depending on what time of the month it is, the Moon may not be up during evening hours. Since we suggest the Moon as a great first target for your telescope you might want to wait for it. Failing that, try to look for the brighter planets.

6) Got a computerized telescope? You might want to ignore it -at first.

And by that we mean the computer, not the telescope. Some models of computerized telescope don’t allow you to operate the telescope without the computer, but if you can try to figure out as much as you can without computer aid before you even start using it. Computers often make many things in our lives easier, but they can also frustrate you -a lot. Most computerized telescopes may require you to have at least some knowledge of the night sky to set up the alignment system (the telescope usually needs to be aimed at a couple of stars to align). This can mean that if you don’t know what stars to point at or if the system is a bit off because a tripod leg is set short than another you can spend a lot of time trying to get the computer to act properly and get frustrated. So rather than doing that spend some time getting familiar with the night sky first by using your scope on bright, easy-to-find objects.

7) Learn, learn learn!

There’s a host of information for astronomy newbies on the internet and in books. Amateur astronomers are very keen on sharing their knowledge and experience with you. Check out the major magazines online websites such as Sky & Telescope or Astronomy. There are a zillion astronomy websites with forums as well you might wish to peruse. Even on this blog we have a collection of Telescope Tips you should check out for helpful advice. Also consider joining or at least contacting your local astronomy club – you can find all kinds of help from them, as well as many other benefits from membership (such as loaner equipment).

If your first night with your telescope is a good one, then you’ll have a much better time with the hobby. But always remember a little planning goes a long way!

Happy New Year!

Interested in buying telescopes?

www.spectrum-scientifics.com

Astronomy Hints #18: Do I need a red light flashlight?

There are many factors that can effect the quality of a telescope session: clouds, turbulence, haze, light pollution, moonlight, and so on. Most of these the astronomer cannot do anything to change, but one of them – night adapted vision, you do at least have some control over. You cannot control everything your eyes do, but you can help them a lot.

Many beginning astronomers often make a common mistake of going from a brightly lit house with their telescope out into the darks skies and start viewing through their telescope immediately. This can be a bit unsatisfying if you are looking at dim deep space objects. The will be extremely faint simply because your eyes are not adapted to the darkness. This isn’t just about the pupils of your eyes dialating, either. (more…)

Assembling the Orion SkyQuest XT8i Intelliscope Dobsonian Telescope – Part 1

A bit of a disclaimer here. This is going to be as much of ‘what’s wrong with the Intelliscope’s instructions as much as it will be a  ‘how to’ for helping set-up your Intelliscope.

005First a little background: Dobsonian telescopes, with their large mirrors and lazy-susan bases have been around for ages but it wasn’t until Orion released their SkyQuest XT line in the late 90’s that they became popular. Previous Dobsonian telescope models had issues with balance and were trick to keep on target.  Odd solutions like weights added to the outside of the telescope were clunky and awkward for basic users. Orion solved the issue by adding the CorrectTension system, which was a spring that held the optical tube of the Dobsonian to the base. It was a simple and elegant solution and it worked very well. The line got excellent marks and was considered one of the best Dobsonian lines on the market . At first Orion just sold a 6″ and 8″ model, then added a 10″ model, a 4.5″ kid’s model, and later a 12″ model.

For several years, Orion pretty much dominated the Dobsonian Market, but when imitators cropped up they decided to improve their classic Dobsonian by adding a computer guidance system (not a computer control system like many GoTo telescopes). Here you would get the advantages of having a computer system to help you find objects. It would not require batteries for any motors and the observer would be the person moving the telescope, using a hand controller to guide them.

The whole system using a pair of magnetic encoders, and development was tricky. The initial plan was to have the Intelliscope completely replace the original Dobsonian line where it would be sold with and without the controllers. This didn’t happen due to some development issues. Once the Intelliscope was ready it was sold both with and without the controllers, but after a few years it was sold strictly with the Intelliscope controller system. This unfortunately left some ‘development scars’  that will show up from time to time as we assemble the telescope. (more…)

Astronomy Tips – Using & reviewing astronomy apps on your smart phone Part 1

So you got yourself a telescope. Great! But you couldn’t afford all those computerized doo-dads that everyone else has on their telescopes and like you see on that one telescope shown in the SkyMall catalog. Boo..wait, you don’t need that! You’ve got a Smart Phone!

iphones

Now Smart phones are no substitute for experience with a telescope, but they can make your life a little easier during an observing session.

First up is the 800 lb gorilla of astronomy phone smart apps: Google Sky Map

googleskyapp

This app is very straightforward: you point your phone at the sky, and based off your location (determined by GPS or other methods) it shows what is in the sky in the direction the phone is facing:

googleskymapscreen

This is great for identifying what is in the night sky, for finding out where deep sky objects will be in comparison to stars you can actually see and so on.

It is not perfect, nor is it a substitute for a Star Map or Planisphere – for one thing it can only show a small portion of the sky (even when using a larger screened Pad. Another problem is accuracy – the Sky Map seems to often be off by an hour or so and it is not certain why.  It may just be the physical limits of the orientation of the phone. Nontheless, it is invaluable as an app

Verdict: Strongly Recommended.

Next up: SkEye

Skeye

SkEye is very much like Google Sky Map except it has a few other features, main that it has the potential to act with your telescope as an object finder!

On the surface, it starts as another planetarium program:

SkEyescreeen

It is somewhat less intuitive that Google Sky Map, starting off with the Red light setting on (astronomers use red light to night disturb their night vision). Some of the setup is a little bit more involved, and we can’t see. It also is not automatically set up to follow your path as you move it around.

On the plus side, at least for more experienced astronomers, you can use SkEye to turn your telescope into a push-to telescope. The process involves ‘attaching the phone to your telescope’, which is a bit on the vague side.

A pro version is available which has fainter stars and shows satellites. The cost is $9.00

Verdict: Better than Google Sky Map for Advanced astronomers – casual users should stick with Sky Map

Telescope Simulator by SUPANOVA

telescopesim

Telescope simulator is not free. It costs $1.39 as of this writing. Its purpose is to give you a realistic idea of what you will see through any telescope. You can adjust the aperture, eyepiece size or pick from 50 popular designs.

The reason for this app is so you can see why there are differences in telescopes. As we like to tell folks buying a telescope: Any telescope will let you see Saturn’s Rings, but the question is how good do they look? This app hopes to answer that question.

By our own tests the appearances were accurate. Of course any such app will lack the real life effects of turbulence, floaters in your eye, and other unpredictable effects, but this is only a simulation, after all.

The major disadvantage is that there are a limited number of objects to view in the app.

Verdict: Planning on buying a telescope? Probably worth it. Otherwise not needed.

Telescope Flashlight

telescopeflashlight

There are actually quite a few apps like this, but this seems to be the most popular one.

Red flashlights are used by astronomers to preserve their night vision. What this flashlight does (unlike regular flashlight apps) is instead of using the flashbulb LED, it simply turns your screen red:

telescopeflashlightscreen

That’s pretty much what it does.

You can adjust the brightness of the light by using the volume buttons on your phone as even a red light that is too bright. It seems to work well.

The bad stuff: Ok, so if it is just a flashlight app, why does it need to access so much stuff on my phone? Does having access to my contact list make it a better flashlight? This stuff is a concern.

Verdict: Works as advertised, but be wary of its intrusive nature. There are other red flashlight apps out there.

Part 2 coming soon!

www.spectrum-scientifics.com

 

REPOST – Astronomy Hints #10 So you got a telescope for the holidays:

Be it X-mas, Hannukah, Kwanza, Solstice or Giftmas this is the season for getting telescopes as gifts.  Sadly, many of these scopes might be rushed into usage and some critical steps might be 016skipped. This can result in a frustrating experience for a budding young astronomer who may give up their new hobby prematurely. This can be avoided if you only take the time and a few precautions to make certain you get the baby steps out of the way without too much tripping and falling.

1) Do as much as you can during daytime first!

I can’t stress this too much. Many folks assume they can assemble their telescope right out of the box at their chosen viewing spot – in the dark. Suffice it to say this is not a good idea.  That is an extreme example but you should also try working your scope and getting the ‘feel’ for it during the daytime as much as possible. Take you telescope outside during the daytime and point it at a nearby tree or other object (the object should be at least 1/4 mile away).  Use this object to align the finder scope (see below) as well as test how the eyepiece focuses. Try changing your eyepieces between the low and high powered ones to see how that works as well. Move the telescope in large movements as well as using the slow motion controls as well. When you do these things in the daylight you can get a much better feel for how they should work than if you try them at night. Also if you drop an eyepiece or loosen a screw you have a decent chance to find it. Get your mistakes out of the way when the sun is up.

2) Assemble your telescope properly

This should go without saying, but it is amazing how many folks skip a few steps or don’t attach parts, or don’t read the instructions properly. We’ve seen telescopes in for “repairs” just after the holidays that were just put together wrong, or some critical final steps were ignored (slow motion controls not attached, counterweights not placed).  Most of the time, there are very few non-critical elements of a telescope’s construction. So be sure to follow the assembly procedure carefully. Allow yourself a couple of hours as well (maybe three hours for certain models of dobsonian telescopes) for the assembly. Don’t assume you can just put it together a 1/2 hour before you plan to head out and view.

3) Align your finder scope. Align your finder scope! ALIGN YOUR FINDER SCOPE!

Get the point? Many folks ignore this step until the last minute and we can tell you that trying to work a telescope without an aligned finger is very,very, very hard. Even the lower 084magnifications on a short focal length telescope only see a little under 1 arc degree of the sky. This is a tiny portion of the sky so hoping to find an object with just the eyepiece is really hard to do. There is a reason why almost all telescopes come with a finder scope. So make sure to align it (During the daytime per suggestion #1) . If your telescope comes with a red-dot finder instead of an optical finder scope, be certain to carefully align that as well during the daytime – and don’t forget to switch it off! A dead battery in a red dot finder is nobody’s friend.

4) Did you get an Equatorial mount? Figure out how it moves!

An equatorial mount has some great advantages over a regular altazimuth (altitude-azimuth) mount. It can track, be motorized, and the larger ones can even be used with setting circles to locate objects in the night sky. But these are only true if you take advantage of the equatorial mount’s features and set it up properly. During the daytime (suggestion #1 again!)  try a rudimentary set-up of the equatorial mount. This does not have to be super accurate as some telescope’s instruction manuals may require, just enough to get mostly accurate tracking for a little while.  Perhaps more importantly, get a feel for how the telescope moves – you are used to moving things in an up/down left/right fashion. Now you need to get used to moving the telescope in declination and right ascension. Try moving the telescope from one target to another using the mount properly during the daytime to get a better sense of it. One thing to keep in mind is that the counterweight is there for a reason – it shouldn’t be pointing down all the time.

5) Choose your first targets wisely!

Many folks go out with their telescope and just point it at the brightest thing in the sky. This is fine if the brightest object is a planet or the Moon, as there is lots to see. But very often at this time of year the planets might not be out until very late and the brightest thing in the sky is the star Sirius.  Problem is, Sirius is just a star and stars appear as just a point of light even when magnified through your telescope. This can be a very boring target and can be disappointing if it is the only bright object. So make certain before you go out for your first night’s viewing that you know what will be up! Most telescopes these days come with some rudimentary planetarium software that can show you what the sky will be like on any night. Failing that there are online websites that do the same thing (sometimes better). Planipheres can also be used, and if you have a Smartphone or pad you should download a planetarium app like Google Sky (its free). Depending on what time of the month it is, the Moon may not be up during evening hours. Since we suggest the Moon as a great first target for your telescope you might want to wait for it. Failing that, try to look for the brighter planets.

6) Got a computerized telescope? You might want to ignore it -at first.

And by that we mean the computer, not the telescope. Some models of computerized telescope don’t allow you to operate the telescope without the computer, but if you can try to figure out as much as you can without computer aid before you even start using it. Computers often make many things in our lives easier, but they can also frustrate you -a lot. Most computerized telescopes may require you to have at least some knowledge of the night sky to set up the alignment system (the telescope usually needs to be aimed at a couple of stars to align). This can mean that if you don’t know what stars to point at or if the system is a bit off because a tripod leg is set short than another you can spend a lot of time trying to get the computer to act properly and get frustrated. So rather than doing that spend some time getting familiar with the night sky first by using your scope on bright, easy-to-find objects.

7) Learn, learn learn!

There’s a host of information for astronomy newbies on the internet and in books. Amateur astronomers are very keen on sharing their knowledge and experience with you. Check out the major magazines online websites such as Sky & Telescope or  Astronomy. There are a zillion astronomy websites with forums as well you might wish to peruse. Even on this blog we have a collection of Telescope Tips you should check out for helpful advice. Also consider joining or at least contacting your local astronomy club – you can find all kinds of help from them, as well as many other benefits from membership (such as loaner equipment).

If your first night with your telescope is a good one, then you’ll have a much better time with the hobby. But always remember a little planning goes a long way!

www.spectrum-scientifics.com

Astronomy Hints #16 Reflector vs. Refractor

This astronomy hints post is going to double cover much of what we covered in our Telescope buyer’s guide but we hope to go into a bit more detail for those considering their first telescope – and that is the raging battle between reflectors (telescopes that use mirrors) and refractors (telescopes that use lenses).

Now we are just concentrating on the telescope’s optical tubes. We won’t talk too much about mounts right now. First let’s take a look at the two designs:

015thumb

Now odds are, if you are looking at these two designs and don’t know a thing about telescopes beyond what TV & movies may show your first instinct will probably be to think of the refractor (the one on the left) as being what you think of as a telescope: a tube pointing at what you want to look at while on the opposite end of the tube is the place you look into. Its very simple, and very intuitive. It even invokes the old brass collapsing telescopes every pirate move seems to be require to show by law.

Conversely, the reflector (on the right) can be a bit odd-looking. First of all, the front end is open and empty! You have to look all down the tube to see any sort of optics 013thumb(i.e the primary mirror).  Then you notice that there is no place to look through at the end of the tube. The eyepiece just kind of sticks out of the side, and the finderscope (a little telescope used to help find things in the night sky) isn’t in the same place as the refractor. What is going on here?

Well, what is going on is that while the result is the same (light gathering and magnification), and some of the fundamental optics are doing the same thing, the fact is they are both doing it very differently.
First up the refractor employs a large lens, located at the front of the tube, to refract (hence the name) or bend the light. This bent light is designed to come to form an image very close to where the eyepiece is located (you can get an idea of how this works by making an image of an object on a wall with a magnifying lens – just remember the telescope is designed to have the image form much further away!). The eyepiece then focuses on this image. In a way this is like having a magnifying glass focus on a magnified image – sort of.

Diagram of a Refracting Telescope

Conversely, the reflecting telescope doesn’t bend the light, it reflects it, or bounces it if you prefer. This is similar to what the mirror on your car or in the bathroom does, except that the mirror in a telescope is curved. So it also forms an image not very far from the telescope’s eyepiece:

Reflector Telescope Diagram.

So now that you know how each is different, the question becomes:

WHICH IS BETTER

The fact is: There is no simple answer for this. Let’s just go over some basics.

Let’s start with the advantages

ADVANTAGES

Refractors:

  • Tend to have sharper images
  • Have more traditional designs
  • Do not require much maintenance or collimation

Reflectors:

  • Are less expensive to build at larger sizes

Seems like Refractors are the winner, yes? No, not really.  You see that first advantage of reflectors is a killer. It is simply much easier to make a larger mirror than a large lens for a telescope. With a mirror, you need to polish only one side and coat it. With a reflector, you need to polish both sides at least two lenses (most refracting telescopes use air-spaced achromats (multiple lenses) and will probably need coat them with an anti-reflection coating as well.  That’s four lens sides, each one with a different curve.

The major selling point of refractors at small sizes is their traditional designs & lack of need for collimation. A small refractor will cost about as much as a small reflector and will give a beginning astronomer fewer things to worry about. The other advantage, the sharper images,  tends to only come with higher-quality refractors or even what are known as apochromatic (3 or more lenses, or two very well designed ones) objective lenses. These can get very expensive, but at small sizes (i.e. easy to transport) the refractors can easily win out with image quality. Many astronomers, not wanting to haul around heavy reflectors, may opt for these advanced refractors.

Let’s look at the other side of the coin:

DISADVANTAGES

Refractors

  • “Chromatic Abberation” – where the lens breaks up the light like a prism
  • More expensive than reflectors at mid and large sizes.

Reflectors

  • Requires occasional maintenance/collimation for ideal viewing
  • “Secondary Shadow” from secondary mirror will cause some loss in the light gathering

Chromatic Abberation can be annoying when viewing bright objects (the Moon, Jupiter, Venus, etc) as it results in what is known as a “violet fringe” around the object. This can be filtered out, and it doesn’t show up much on dim objects (light galaxies, nebulea, etc.) . But it can be frustrating to some novice viewers.  More critical to refractors is the expense of making medium and large-sized models. We already covered why in the advantages section.

Reflectors on the other hand have the problem with collimation. Most large reflectors are probably going to need collimation if they’ve been moved around a lot. They will still work if they aren’t precisely collimated, but the images will appear streaky. Collimation can be a bit tricky to master and so can frustrate novice astronomers.

The secondary issue is bit of a misnomer. What it essentially says is that any reflector telescope is not going to gather as much light as its full surface area as a portion of it will always be in the shadow of the secondary mirror. This is mostly just a nuisance as if one needs more light gathering power one simply makes a larger primary mirror., but then weight does become an issue.
So to answer the question of ‘which is better’, there really isn’t much of a straight answer – at small sizes (for beginners)  there is little reason to not get a refractor. But once the sizes get larger the reflector very quickly becomes much more economical. These rules are in no way ‘hard and fast’ as there are many exceptions to them. But as an overall guide they can give you an idea of what design to look at.

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Astronomy Hints #15: Filter! Filter!

One of the more wide-range things to use in astronomy are filters. There are a large number of them and their purpose varies greatly. They can reduce light, help with light pollution, bing out details, or help with astrophotography. Most filters thread on easily to telescope’s eyepieces and can change your viewing experience.

But when choosing filters one must remember this: They are filters, they are designed to remove something, even if it is unwanted. Some folks get the idea, especially with light-pollution filters, that filters make objects being viewed much brighter. But that is not the case. Think of it this way: if you have a kitchen odds are ou might have a water filter in your faucet or some kind of pitcher. When you use this filter you do not make more water by using it, you are merely removing the stuff in the water you do not want.  Water filters are actually pretty good because if you put 1 liter of water over a water filter odds are you will end up with very close to 1 liter of clean water. But you won’t end up with 1.1 liters. Sounds obvious, but some folks get the idea that that is what astronomy filters can do. But it is not so. In fact using an astronomy filter on the light from the stars means you are going to lose some of the good light along with the stuff you do not want. If we go back to out water filter you can think of our 1 liter of unfiltered water becoming .9 or even .8 of a liter.

But let us discuss the various types of filters:

Moon Filters

Moon filters are simple neutral density filters (which means they evenly cut down on light across the visible spectrum) that thread onto your eyepiece. They are used because the Moon is actually very, very bright and viewing it in even small telescopes at it can hurt your eyes after a short time (not permanently, mind you). A Moon Filter can make viewing more comfortable. Typically filters allow in 25% of the light, or 12% (for larger telescopes)  or in a variable model you adjust yourself .

Solar Filters

Solar filters are the only filters that do not thread onto the eyepiece. The go over front of the telescope. If you find a ‘solar filter’ that is meant to thread onto an eyepiece, destroy it immediately. Those are very dangerous as they can crack letting through sunlight that can damage your eyes. Don’t use them, Don’t keep them – someone else might be tempted. Destroy them.

Most solar filters are simple screens of Mylar that cuts down on 99.999% of the light so that you can safely view the sun. Mostly what you will see is a white disc with some sunspots.  It makes for some nice viewing during the high points of the sunspot cycles, during the lows the sun can seem a bit featureless, however.

Another type of Solar Filter is the Hydrogen-Alpha Filter. These allow you to view reddish colored prominences and solar flares. They are very expensive, however (in the thousands of dollars) and they need a certain amount of ‘tweaking’. But they can give very impressive views of solar activity.

Color Filters

Color Filters are used on the planets or the Moon – they cut off too much light to use on deep sky objects. Color filters are used to try and bring out more details on the planets that might get washed out in regular filtering. Details brought out might include the bands on Jupiter, polar caps on Mars, more lunar crater detail, and so on. Color filters can be hit-or-miss among astronomers. Some think they are great, others find them less useful. The field seems rather subjective but if you plan on viewing the Moon & Planets more than anything else you might wish to invest in a set.

Light Pollution Filters

Light Pollution Filters are designed to help astronomers who live in light-polluted suburbs or cities. They are not a substitute for dark skies, but they can certainly help out when options are limited. Light pollution filters help by cutting down on frequencies of light that streetlights, parking lot lights, and other human-made light sources produce, while letting through most of the light that stars, nebulea, and other deep sky objects emit.

This set of quickie photos can give you and idea of the effect of the filters. Here is a shot of a city streetlamp that is on during the daytime:

Street Lamp, through a phone camera, daytime, unfiltered.

And then with an Orion Ultrablock Filer held over the lens:

Same streetlight, with light pollution filter held over the camera lens. Note the difference.

You will notice that the filter helps, but does not completely eliminate the streetlight light, and it does have some effect on the natural background light as well. This is why they are helpful but not a complete solution to dark skies.

Light Pollution filters also are of little use on the Moon (which is bright enough to not be bothered by light pollution) or the major planets (which are similarly unaffected by light pollution). They are of limited effect on the outer planets as those planets emit light over much of the spectrum and get filtered as much as the background light.Some light pollution filters may be referred to as Nebula filters, which are very focused and are even designed to cut down on some of the light from nearby stars.

Astrophotography Filters

There are a huge number of these and their uses could fill a book – a book about astrophotography that is. These filters do things like cut off the IR portion of the spectrum (which messes up CCD chips in digital cameras) or filters out only the all but the Red or Green or Blue part of the spectrum for monochromatic cameras. The number of these filters has expanded vastly in the past few years. Covering these would take a very large entry so we will leave them for now as it is beyond the scope of Astronomy Hints.

Refractor Violet Filters

These filters are for one type of telescope – refractors. The large lenses in these telescope sometimes act as prisms and break up the light into component colors. This is especially noticeable on bright objects like Jupiter or the star Sirius. The effect is that the object being viewed will have a violet colored halo that is affectionately known as ‘purple haze’. Violet-Minus filters cut out this portion of the spectrum without affecting overall viewing much.  If you have a larger refractor that sometimes shows the ourple haze you might consider getting one of these filters.

www.spectrum-scientifics.com