Hello, I am new, could do with a little help

[davetucker]

Hi,

Have just bought a Celestron 130 SLT telescope, and very new to astronomy, and could do with a little help. When I bought the Scope it came with several eyepieces:

1. 6mm
2. 8mm
3. 13mm
4. 17mm
5. 32mm
6. 2x Barlow Lens

I have no idea what these lens do, and which I should start with. I have used the 32mm and was amazed at what I could see. I am able to align the scope with no problem, just need a few pointers to get started.

Warm Regards

Dave

[Ray02]

Well first off all if you are new why you bought a telescope? Why you didnt start with binoculars?

Sent from my iPod touch using Tapatalk

[Dave In Vermont]

I started with a telescope too. And I'm quite glad I did - I loved my 75mm F/15 refractor!

The eyepieces act to magnify the object you are seeing. To find out the of your eyepiece, you first find the focal-length of your telescope. The Celestron 130 SLT is a Newtonian Reflector which is an F/5. So we take the aperture (size, or opening) and we multiply this by the F-number:

130mm X 5 = 650mm.

Now we divide the focal-point of the eyepiece by the focal-length of the telescope. Let's take your 17mm eyepiece:

650mm / 17 = 38.235X

So your 17mm EP (eyepiece) gives you a bit over 38X.

I'll let you digest that. And soon someone else will come in to explain some further details for you!

Oh yes_ Greetings & welcome to SGL, Dave. We're a friendly bunch that enjoys helping people find answers to questions about every facet of the Universe we call astronomy! So don't be shy - pull up a chair and make yourself at home -

Clear skies,

Dave (also)

[ronin]

Well first off all if you are new why you bought a telescope? Why you didnt start with binoculars?

Sent from my iPod touch using Tapatalk

Probably wanted a telescope as I did when I started.

Eyepieces:

1. 6mm
2. 8mm
3. 13mm
4. 17mm
5. 32mm
6. 2x Barlow Lens

The eyepieces give the magnification to view the objects with, you vary this depending on the object, what you want and to a fair extent the brightness of the object.

Start with the 32mm, it will give the lowest magnification but the widest field of view. Simply means this is most likely to get the object into view.

Centre the object then if wanted got to say the 13mm to make it appear bigger and so hopefully see more detail, then you can go to the 8mm and give that a go, whether the 8mm will work or not I do not know - simply as the magnification goes up the image detail tends to go down.

So it becomes a compromise.

I see the scope is a reflector and f/5 so then 6mm should be OK on it. Focal length is 650mm so the 32mm eyepiece will give about 20x and a field of view of about 2.5 degrees (guessing here).

If you are looking at something like Andromeda then you will need the 32mm, Andromeda is somewhat BIG.

Better example is Pleiades or M42, both generally about 1 degree across. With your scope and eyepieces the 13mm will give a view of about 1 degree so the Pleiades and M42 will just fit the view. So if you go higher for magnification then you lose some of the object off the edges.

One M42 it means you magnify in to see the Trapesium in more deatil but on the Pleiades you simply drop stars off the edges.

Again a choice needs to be made.

Magnification = scope focal length / eyepiece focal length, so 650/32 = 20x (approximately)

Field of view = eyepiece field / Magnification, useing the above and assuming the eyepiece is a 50 degree one then FoV = 50 / 20.

You need mental arithmatic for this hobby, at least in a little.

Stick with the eyepieces you have - assuming they give an acceptable image to your eye, not all do or will.

I see the scope apprears to be  goto, how is the setup and alignment of this aspect going?

Or have you not tried it yet?

Small edit: I forgot the barlow - this is used to double the focal length of the scope, means you can get higher magnifications or in effect use the eyepiece as if they were half the focal length. For the ones you have there seems little use for it. If you half each eyepiece focal length you end up close to one of the other eyepiece focal lengths, also unless the barlow is good they can produce a poor image. At this time I suggest you leave it out of consideration.

[Tinker1947]

Welcome to SGl, you have quite a bit of learning to do, mostly by learning as you do thing, so the EP's the numbers indicate the amount of power the magnify  by the Higher the number the less it will magnify, so the 32mm is the one you use to find DSO's its a has a wide field so your see more of the sky, the lower the number the more magnification you get up to around 250X after this point it mostly gets blurry you can work out the magnification by dividing the focal length of the scope by the number on the EP in your case 650/32 + 20.3 magnification you most powerful without using the barlow is  X-108 thats the 6mm EP, the barlow will double this and double any of the other EP's,,,,thats your starter for now, my fingers are going numb....

[John]

Hi Dave and welcome to the forum

Congratulations on your new scope - it's a good one!

You have a good range of eyepieces there - as the focal length of the eyepiece in mm goes down, the magnification that they provide increases.

To work out the magnification you divide the focal length of the scope (650mm I think for your scope) by the focal length of the eyepiece so they give the following magnifications:

32mm = 20x

17mm = 38x

13mm = 50x

8mm = 81x

6mm = 108x

The Barlow lens has the effect of doubling the magnification given by each eyepiece. You put the barlow lens in the scope and then put the eyepiece in the barlow lens.

The low to medium magnifications are good for viewing deep sky objects such as star clusters, nebulae and galaxies.

The higher powers will be good on the Moon, planets and double stars.

I'd practice using low to medium magnifications then increase the power until the view is good but don't go too far. Many objects look better with low to medium magnifications. Your highest is 216x (108x X 2) and that might be too much unless conditions are really good.

Have fun

Note: several folks posting similar helpful info here but I hope it's all reasonably clear !

[miafey]

Hi Dave, 

Welcome to SGL and I am only one day older than you are on this forum

There is a pinned thread here "Eyepieces - the very least you need" which I found very useful. 

Hope you enjoy your scope!

Mia

[Stu]

Well first off all if you are new why you bought a telescope? Why you didnt start with binoculars?

Sent from my iPod touch using Tapatalk

I trust that's not the sort of welcome you received on SGL? How negative.

Buying a scope a learning the skies is how I started off, nothing wrong with it at all. Plenty of good advice being given thankfully.

[Charic]

Hi davetucker, welcome to SGL.

You will  find  wider views from using the higher numbered eyepieces, and when you want to get in closer, start progressing towards the lowest numbered eyepieces. 

The 2x Barlow  is clever, it  extends the the focal length of the telescope by a factor, printed on the Barlow. The effect of this can increase you eyepiece collection? You  now have, when using the Barlow a 3, 4, 6.6, 8.5 & 16mm eyepieces, so quite a range.

See what's happened? your 8mm works like a 4mm and the 6mm work like a 3mm when used in conjunction with the Barlow. Just slip the Barlow into the focuser, and whatever eyepiece you insert, it is now twice as powerful, but hold back, as many of the views up there require low power and wide angle to encompass what your seeing, but on a good  night of seeing, ramp up the power and check out the Moon. 

Edit: 6 entries by the time I wrote this one, need to refresh more often!

[seo]

First of all, Hi Dave and welcome aboard !

Secondly IMHO I totally agree with BigSumorian, about Ray02 answer... but everyone has an opinion and a free speech... up to a point of course.

Lastly as others said your choice was good and also most of your "first" questions are only 2-3 clicks away from your mouse in this forum... besides that I personally think that 8mm. 13mm and your 32mm will cover most of your first observations.

Enjoy the forum

[Dr_Ju_ju]

Hi Dave, welcome to the Lounge and wishing you clear skies.

[Dave Lloyd]

Hello Dave, welcome.

[Floater]

Hi, Dave, and welcome.

All good advice above, as usual on SGL. Kick the negative reply into touch - that's NOT usual ...

Have fun with the hobby and the forum. Both can be fascinating.

[Alien 13]

Welcome on board when I had my 1st scope the low power eyepiece is the one that got used most I was enthralled by the endless star fields without having a clue what I was looking at.

Alan

[Astro Imp]

Hi Dave, welcome to the forum. 

You've received some great advice, enjoy your scope and the forum.

Well first off all if you are new why you bought a telescope? Why you didnt start with binoculars?


Sent from my iPod touch using Tapatalk

A very disappointing reply to a newcomer to the forum, try and think how you would feel if you received a similar answer to a perfectly reasonable question.

[NigeB]

Hi Dave,

Welcome to SGL - and congratulations on your new telescope!

Like you, I went straight into astronomy with a telescope (a 60 mm Bresser which my parents bought me) and all was well. I recall walking into the living room to see it on Christmas Day. It was magical. I hope you get the same feeling when you see yours.

There's some really good advice in the replies you've had. Let me add one thing... As others have said, the higher magnification (shorter focal length) eyepieces can yield poorer views (less stable, less sharp, dimmer) than the longer focal lengths. So as you get used to the instrument and clock up more hours under the sky, you'll probably find yourself using the longer focal lengths more often.

But don't give up on those shorter ones - as Charic has said. Much depends on the "seeing", which means the stability and clarity of the atmosphere you're looking through. All nights are not equal - occasionally, the conditions can permit pushing the power higher, provided your telescope mirrors are well aligned ("collimated"). Those nights are frequently the most memorable for visual observers. And those nights aren't necessarily the ones which are "crystal clear" -for example misty evenings are often accompanied by very calm and stable atmospheric conditions, and the planetary views can be pretty good in the time before your telescope is drenched in moisture... 

Nigel

[davetucker]

Wow thank you all so much for taking the time to respond to my question. I can see it is going to be a steep learning curve. i would like to join one of the local clubs, unfortunately the nearest one is a 60 mile round trip, so logistically difficult. a lot of info on this post, which I will take on board, and best of all get to experiment with the Scope, loved looking at the Milky Way last night, simply beautiful.

Dave

[Erla]

Hi Dave,

Don't worry, I bought a similar telescope a year ago, it was a bit frightening at first with all the mm, focal length and apertures, but I just went outside and played with it, moon is a big target. It soon started to make sense and I was taking pictures of Jupiter in a matter of weeks. Some of the Celestron eyepieces were iffy when compared to more expensive ones I purchased latter, but for the start - all good. One addition to the telescope I couldn't recommend more is Telrad. Couldn't find a thing without it, now it's point and view.

[cjdawson]

Hi and Welcome to SGL.

Skimming through the above posts.  It looks like you've already had your immediate question answered.

I too started out with a Telescope.   I remember that time well (few shimmering fade effect as we flash back to a winters evening in 2002)   After coming home starry night after starry night, curiosity got the better of me.  I went to Argos and bought they're "best" telescope.  It was a Tasco 114 Goto telescope.  Required 8AA batteries, and when i got it home, set it up and tested it out.  The instructions were very good, told me all about collimation - shame that everything on the scope was so tight that I couldn't actually do the collimation.  Unstopped by that, I took the scope, already mounted to the tripod under my arm out to a near by field, and plonked it down in the middle of the field.  I did the two star alignment process and chose the tonights best guided tour.  Off the scope went,  when it stopped, I looked through, focused drank in the site of Jupiter and the galilean moons.   After staring at that site bewitched for what seemed like an age (20 mins, I live in a fast paced world), I chose the next target.  The scope slewed a tiny bit then stopped.  I looked in and again I was mesmerised by the sight of Saturn, rings at a tile, as if bowing.   I wasn't able to split the rings, but I didn't know about that, then again after another eternity (I might be exaggerating slightly) I slewed on to the third object of the night.  Slewed in, looked into the eyepiece and this time my jaw dropped open as my eye was swamped with the majestic view that can only be described as the Great Orion Nebula, my eye's drank that up for the rest of my life.  (ok, ok, the rest of the session).  I was going to slew on to object number four, to this day, I dare not ask what object four would have been.  But the session was cut off by a cover falling off the scope.  Also the batteries were already struggling and were probably going to run flat any moment.

I slept on it, then next day, saw that the cover that had fallen off was only going to get worse, so back that telescope went to Argos Yay for the 30 day money back guarantee  And I set about getting a new scope.  Did some research and was going to get a Meade ETX-125 (best scope of it size for the time) however, the guy at the Astronomy shop (SCS Astro) convinced me that as I was interested in eventually doing Astrophotography, to go up a level to the LX-90 which was the best scope of it's kind at the time.  15 years later, I still have that LX-90, I agree with him that at the time it was the very best scope for the money.  The LX-200 would have been better but it was way over my budget, the LX-90 was stretching my as it was.

So, I too bought a telescope before really knowing what I was doing.  The learning curve is steep, it's long and it's hard to short cut it.  Having said that, a forum like this one, can save lots of time and money in helping to make good choices, and for learning.  I hope you enjoy your telescope as much as I have, and continue to.

[glowjet]

Hi Dave and welcome to SGL, enjoy your new scope and all those optics you have to go with it. Binoculars by the way are not mandatory, to get you started in the field of Astronomy, they are, however, a very useful piece of kit to have and as time goes by, you just might, at some time in the future, consider obtaining a pair. Very useful for scouring the Constellations, hunting down that illusive target, enjoy the forum 

[BritAngler]

Hello Dave, and welcome to the forum

I agree with the others, totally disregard the post from Ray02, that is not the sort of reply we are used to on here, especially to a newcomer!

There is no hard and fast rule which states "You are new to astronomy, you MUST start off with binoculars", even though many of us will have at least one pair by now. My first telescope was nothing more than a cheapo refractor of the type you can buy in Argos, but the first look at Saturn had me hooked for life; binoculars simply would not have had the same effect.

Enjoy the forum, but more importantly enjoy your telescope and finding out the capabilities (and limits) of the eyepieces

[Size9Hex]

Hi Dave, welcome to SGL. This is the friendliest forum I've seen from the various forums I use in various hobbies. The earlier reply is very out of character.

I'm new to the hobby too. Started with binoculars a couple of months ago, and I'm already thinking of acquiring a telescope for a better view of the skies. From that point of view, you've just taken a sensible shortcut!

I can't offer as much advice as most folks here but the thing that has helped me most was having a map of the sky. There's a good monthly download from skymaps.com showing what you can see each month. Sky Safari for iOS is great. A lot of folks here have praise for Stellarium on PC too. The sky and telescope star atlas is also excellent.