first telescope and sighting

[mickyslick]

Hello everyone,

So i finally figured out what telescope I have. It is a Celestron NexStar 4gt. This is all I know about it. I finally got a chance to take it out to a place with few lights and on a clear night. Now, I don't know much about telescopes or stargazing, so I downloaded Google Sky Map to help me get a feel of what I am looking at. For the first time, I saw Saturn, and it was, for lack of a better term, a religious experience. I cannot explain the rush i felt when I saw it for the first time. Simply amazing.

Now, I am in need of some help with figuring out this telescope. While I could see Saturn, and the rings, they were every small seemed more like a large star then a planet. I understand that my telescope is not the most high powered one out there, but I guess I was expecting to see something more. When I looked at Mars, I couldnt make out any details at all. It was extremely bright, but that was about it. I am using a 25mm eyepiece right now, as that was what came with the telescope. If I got a different eyepiece, would that make a difference? If so, what would you recommend? And I am in need of a tripod for this bad boy, and after doing a quick search online I see that it is discontinued and no longer available. Is there some other alternative? Could I just get a camera mount?

Thank you for reading this! Happy Stargazing everyone!

[rory]

hi micky, theres alot of stickies and tutorials on these pages that will help you along .

but to get you going, mars is difficult at the best of times and its not at its best now ,so it will be a tough one to get any details from. with your 25mm eyepiece ,thats a low power eyepiece. the higher the number = low the power. so a 12mm eyepiece for example will give twice the magnification of a 25mm.

but dont be fooled by thinking more power is best, because its often not the case.

download "stellarium" its a free software that will show you everything in the night sky and its location.

as for a tripod . how the heck was you useing it without ?

http://www.stellarium.org/ here the stellarium link micky. and check out the stickies at the top of the forum pages.

[Capricorn]

Appears the the scope has a focal length of 1325mm, so a 25mm eyepiece means 53x.

To see Saturn you need about 100x or a bit more.

To see Mars you need a lot more, something like 200x.

The blurb says max magnification of 240x, I would say more like 150-180x.

A 12mm eyepiece will give 110x, so if you get the chance try one and see how it performs.

Saturn should be decent with that magnification.

A 10mm eyepiece will give 132x, an 8mm will give 165x

Really think 165x is as much as sensible and it may be too much on many occcasions.

If the 25mm you have is OK then try a 12mm and 15mm (maybe 18mm) as additional options. Being f/13 plossls should be fine and for the focal lengths mentioned will give reasonable eye relief. Below 10mm this could be a factor.

Being a Mak you will may need a 32mm simply to get some wider views at times, a wide angle 25mm may be OK.

[DirkSteele]

There are a few easy to remember formulas you should know that will help you to understand what a particular eyepiece will do in terms of your telescope.

The first is the magnification it will produce. Take the telescope focal length (in your case 1325mm) and divide it by the focal length of the eyepiece (25mm), which gives a resultant magnification of 53x. If you did not know the focal length but do know the aperture and focal ratio, simply multiply one by the other so, in your case 102mm x 13.

The second is field of view, i.e. how much of the sky will the eyepiece show when used in your particular telescope. There are two ways to calculate it. The first is take the field stop diameter of the eyepiece, divide it by the telescope focal length, and then multiply that by 57.3. The field stop diameter may well be detailed in the instructions. The second way is if you know the "apparent field of view" (plossl eyepieces are typical 50 degrees), then take this number and divide it by the magnification it produces in your telescope. So assuming it is 50, the field of view will be 0.94 degrees.

To give you a concept of what that means, the full moon is approximately 0.5 degrees across. So your eyepiece would almost show 2 full moons side by side. Now your target Saturn appears much, much smaller. On average Saturn is around 18-20 arcseconds. There are 60 arcseconds in an arcminute, and 60 arcminutes in one degree. This means Saturn is only about 0.0055 degrees across. Compare that to the moon, and you start to see that higher magnifications are needed to reveal details on the planets.

A word of warning though, you cannot boost the magnification to ridiculous levels. First atmospheric turbulence will cause the image to blur, and as a rule of thumb, about 50x per inch of aperture is the max a scope can deliver. So in your case, about 200x.

Hope this helps,

Matthew

[glowjet]

I think by the time you have assimilated what has been said, you will understand a little about your eye pieces, there is another addition which I can suggest and that is the use of what they call a Barlow. An optical device that you can use to increase the power of your lens, most popular are the 2X which can double the range of an eye piece without having any undue effect on its optical ability. You now have a device which will effectually double your eye piece range. To have one of these devices in your kit will give you a little more latitude when choosing your optics, however it is unwise to buy a cheap quality unit, makes like the Tal 2x is very popular and most often recommended

John.

[Mogga]

I would really love to know how you were looking at saturn without a tripod?

[mickyslick]

Thank you so much for all of the information! Looks like I'll be looking for a telescope shop near my house this weekend.

As for questions about how I was using my scope without a tripod, its a simple answer: a very sturdy table.

Will a normal camera tripod be able to hold up my scope?

Sent from my DROID RAZR using Tapatalk 2

[rory]

""Will a normal camera tripod be able to hold up my scope?""

id say no. once you use higher magnification you need a sturdy lump. i suppose you could hang a heavy wieght from it to give it some stability, but really you want a astronomical mount of some description.

if your scope is light/small you might get away with it .

[cantab]

Just for clarity, do you have only the tube, or do you also have the mount, as seen here:

http://www.atozastro.com/shop/scripts/prodView.asp?idproduct=75

[mickyslick]

Yes I have the whole mount, just not the legs for it

Sent from my DROID RAZR using Tapatalk 2

[glowjet]

Try Scope n Skies Astro Boot for the legs, you may be lucky

John.

[earth titan]

I would really love to know how you were looking at saturn without a tripod?

Me too. What did you use?

[mickyslick]

Me too. What did you use?

Lol, I just used a Table, since my scope has the bottom mount for it, just not the legs. It was a little shaky for a bit, had to hold my breath while I was using it. It worked ok, but I know that it would be much better if I had the tripod