what can i expect to see?

[moondog78]

hi everyone, just after a bit of advice please. ive bought my 10yr old boy a telescope for xmas after months of begging, i bought him a synscan skywatcher 1145p. (maybe i jumped the gun a bit and bought the first scope i came across that looked the buisness, and now wishing i had maybe bought him something else like a dob) anyway. we had our first look thru it last night. no moon visable and really cloudy alought there was one bright star in the sky which i am presuming was actually jupiter. it was in the south west sky. howvere it looked merely like a white dot, no more than 3-4mm in diameter and you could just make out pin ***** dots either side of it, Presumably its moons.

to be honest i was really dissapointed( i think i was more exited than my son at getting the scope out of the box) but am now feeling a bit deflated.

i know that when the moon is visable we will get a great look at the moon with the scope but i was really looking forward to showing my lad jupiter and saturn.

sorry for the long message, i just wanted some input as to if i was doing something wrong or if what we were looking at was all we can expect to see( as in detail ) i honestly thought we would have been able to see jupiter as more than a white spec.

thanks in advance

Dave

[brantuk]

You have a focal length of 500mm and the ep's supplied (10mm and 25mm) will only give you 20x and 50x magnification respectively. To see a bit more detail on Jupiter you will want to ramp it up a bit to 100x to 150x but you'd need high quality v.expensive ep's to do so with that scope, and the image though clearer, would still be small.

You could try a barlow like the Tal 2x or 3x, very good value for money and reasonable quality - and maybe look for a second hand TV 12mm or 15mm plossl to go with. Try not to exceed about 80% of the maximum stated magnification for the scope (around 180x).

There are other options but that's the way I'd be thinking - hope it helps

[iamjulian]

Even with quite a bit of magnification, the planets are still rather small. You have to temper your expectations and be amazed that you can see them at all, considering how far away they are. That said, do you know which eyepiece you were using? Say you were looking through a 25mm eye piece, that would be 20x magnification. I think your scope maxes out at about 220x magnification, though around 150x will probably give you the sharpest views. The dots either side were indeed its moons.

Don't worry about not getting to see what the pictures in the books show you, get a book like the Dorling Kindersley (sp?) Universe book and read about all the things you can both see. He won't care that he cannot see it in minute detail, but if he knows what it is he is looking at it will make it every bit as impressive to him - just looking at stars could become a bit dull. It's know what you are looking at that makes it worthwhile.

He will love the moon!

[Arushin]

Hi Dave and welcome,

First of all... nice little scope!

Don't be too disapointed just yet. As I am sure U.K. users will agree, we do not have anything like good viewing weather at the moment.

The moon will be very cool through this scope but don't expect too much out of the planets from an F5 scope with a 114 mm aperture.

You should get a little more out of Jupiter than a white blob but there are a lot of things to factor in. Jupiter is past its best now, the 'seeing' is mostly rubbish and an F5 scope is not very forgiving with cheaper eyepieces. With a small aperture you won't be able to push the magnification up too much either. These are good little scopes on bright DSO's though. I have a 12" F5 dob which is fab for DSO's but it gets blown out of the water by my F15 Mak 127 on planets.

[moondog78]

thanks for the replys, yes cant wait to have a look a the moon. i bought my daughter one of those infinity telescopes and had a look at the moon and it was amazing, so cant wait to have a look with the big telescope. as for eye pieces it did come with a barlow x2 as well as the others ( the 10mm and 25mm) we also have a 35mm from the infinity.

we used the 25mm with the barlow last night, so what magnification would that be?

[brantuk]

To get the magnification divide the size in mm of the eyepiece into the focal length (again in mm). A barlow doubles the power of an ep (or halves the mm size).

So your barlow turns the 25mm ep into 12.5mm - divide that into the focal length of 500mm gives 40x magnification.

[Ian123]

For magnification just divide your focal length of your scope by the size of the EP.

Therefore Brantuk mentioned your focal length is 500mm divided by 10mm(EP) gives you 50x.

For the barlow it's a 2x so just half your EP, eg..your 10mm becomes a 5mm

Anyhow i think that's right, good luck, enjoy.

[Ian123]

Brantuk beat me to it

[brantuk]

Lol Ian - I've answered that one so many times I should really set up a cut 'n' paste then substitute the numbers in for the scope

[black5f]

we used the 25mm with the barlow last night, so what magnification would that be?

Hi there

500/25 = 20x You will need the barlow and the 10 to pick up any detail on Jupiter (500/10) *2 = 100

But, it almost entirely depends on what the atmosphere is up to! Don't be dissapointed, the best seeing is about one day a year. Seeing is rubbish at the moment (he says waiting for a clear morning for Saturn. But dont give up, patience. While you are waiting though, download Stellarium, it's free and you can tour the skys to see whats comming up. Also playing in the daylight will help you get used to the scope, play with eyepieces / barlow combinations, focus etc. You will see the effects of the atmospehere etc on distant ground objects.. blury you will find, not your scope, air. Usual dissclaimer.. NEVER LOOK AT THE SUN THOUGH and have fun. Tom

[moondog78]

once again gents thanks for the advice.

ok i can see now that we were not using the full magnification of the scope. novice mistake i guess! thought the bigger the ep (in mm)the more magnification! i see now its the other way around.

what about filters? should we be using them as standard?

thanks

dave

p.s sky is looking a little clearer today so after the advice i am really looking forward to having another peek tonight!

[brantuk]

I've only used a filter on the full moon - never needed it for planets at all. It's a personal thing though related to how sensitive your eyes are and how long you look at an object.

It's up to you to decide this one. As an alternative - if an object is too bright, you can reduce the glare by replacing the main lens cap and removing the small one within it. On a full moon you'll still have enough light grab for comfortable viewing

[OutThereSomewhere]

Do entry level telescopes have photos on the packaging that give example photos of what you could expect to see of Jupiter / the moon / a DSO using various eyepieces? Are examples displayed on the walls of astronomy shops (I've never been in one)? As a newbie, I tried Googling around to find out but this info wasn't very easy to find. Maybe it was just my poor Googling, but I imagine that there are a number of people new to astronomy with the same thoughts as Dave and I.

Jonathan

[John]

With the exception of the moon, photos are not representative of what you will see visually though a scope. Our eyes can't compete with modern CCD imaging and processing so the visual views are generally rather fainter and more subtle.

Looking on the WWW for drawings done at the eyepiece with comparable scopes is a better guide and even then you need to bear in mind that the observer may have had optimum viewing conditions and an experienced eye. Such factors enable details that would otherwise elude the viewer, to be seen and sketched.

One thing that is certain is that you will see more, the more you look so don't be put off if your early views don't match expectations and are a bit dissappointing - visual astronomy needs patience and practice like many other pastimes.

[moondog78]

would using a ccd imager (webcam) deliver better views?

i have bought this bit of kit, but want to get to grips with the basics before going down the line of astrophotography. seems very complicated

[umadog]

These are fairly representative views of Saturn through small scopes. Simulated Telescope Planet Images

Scroll down to the 3" at 100x image.

Jupiter somewhat like this: Jupiter In A Telescope

The only thing I'd say is that the image ought to look a little sharper but the colour contrasts won't be as pronounced. You will get far, far, sharper planetary views by eye then with a webcam. The sharp photos you may have seen are taken with high quality kit by highly experienced people. Forget astrophotography for now. Learn to find stuff in the sky and the basics of visual observing. Serious AP is a different and very expensive, but worthwhile, hobby.

Your scope is F5 and I don't think anyone has mentioned this yet, but that means it needs to be well collimated. Chances are that it doesn't come with a suitable tool. It may come with a collimation cap but I'm afraid that isn't sufficiently accurate for your purposes. A Cheshire/sight tube is probably what you want. You can double check collimation with a star test. This will get you started:

Collimation

John Reed Home Page Collimation - Cheshire

http://www.oarval.org/StarTest.htm

Hopefully your mirror has a white centre spot to aid collimation.

Without getting complicated, if you don't collimate (align) the optics then the image will be blurred and you won't see fine details. If it's badly out of alignment then you'll loose light and the image will actually be dimmer then it ought to be. If you get stuck, let us know where you are. Perhaps someone is willing to meet up and lend a hand.

[moondog78]

THANKS FOR THE ADVICE, OK SO TO COLLIMATE THE SCOPE DO I HAVE TO BUY SOMETHING TO DO THIS? I CANT SEE ANYTHING THAT CAME WITH THE SCOPE THAT RESEMBLES ANYTHING IN THE LINKS YOU PROVIDED.

WHEN COLLIMATING THE SCOPE O YOU DO THIS IN DAY TIME OR NIGHT SKY?

I TAKE IT THAT THE SILVER SCREWS THAT ARE AT THE FRONT OF THE SCOPE AND THE BACK ARE NOT ONLY TO HOLD THE MIRRORS IN PLACE BUT TO ADJUST THE ALIGNMENT OF THEM?

THANKS IN ADVANCE

DAVE

P.S WE LIVE NEAR TYNEMOUTH ON THE COAST, JUST OUTSIDE OF NEWCASTLE.

I DONT SUPPOSE THAT THERE ARE ANY ASTRO CLUBS THAT ANYONE MIGHT KNOW OF NEAR TO US?

[John]

I would not start adjusting the collimation of your scope until you have used it a few times. It may need doing but then again it may not need much adjustment - you won't be able to tell until you get it under the stars.

Collimation is not terribly difficult but it's quite possible to end up with the scope more out of adjustment than it was before you started unless you take a systematic approach, which starts with trying it out under the stars.

[umadog]

Yes, the screws are there to do a job. As John says, don't start turning them for no reason but if they need to be adjusted then go right ahead. If the thing is out of alignment then go ahead and sort it out. You can, even without a tool, use a high-power eyepiece and a star test (google it). When de-focussed you should see concentric circles. I warn you, however, that checking collimation with a star test does take some experience. Best thing is to buy yourself a Cheshire tool and spend a couple of hours with the links I sent you. There are fancier tools out there but their cost may start to rival what you paid for the scope so ignore those for now. Cheshire should be fine.

You do the alignment during the day. Read about it and it should make sense. Look around on the CloudyNights website too; collimation is an issue that comes up all the time.

Once it's aligned it ought to stay pretty much OK unless you knock the tube. I have a truss tube so I always check the collimation before each session, even if I haven't dismantled the tube between sessions. Even changing temperatures during the night can alter collimation.

I will say one more thing, however. Poor collimation will degreade the views of planets and the moon more than nebulae and galaxies. This is because deep-space objects always appear fuzzy. Don't loose too much sleep over it now. Get out and use the scope whilst you wait for your collimation tool. You'll still see plenty. I home-built and F6 Dob and never used a Cheshire on it. I just star-tested it. Views were always pleasing.

[moondog78]

OK, I HAVE TO ADMIT THAT WHEN LOOKING AT JUPITER THE OTHER NIGHT IT DID SEEM TO BE QUITE A SHARP IMAGE EVEN THOUGH I WAS ONLY LOOKING AT IT AT 20X MAG. I COULD MAKE OUT ALL FOUR MOONS SO MAYBE ITS NOT TOO BAD AT THE MOMENT.

[umadog]

Quite possibly it's not too far out of alignment. I reckon a small scope like that with a solid tube is more likely to maintain its collimation than a larger scope.

p.s. we can also read text that isn't written in upper case