My Telescope Question

[Lsh1482]

I am an ameteur. I Have been trying to look at Saturn. I have a Meade 70EXT. THe eyepiece is 25mm. I bought a 6.4 mm eyepiece and a 2x Barlow lens.

The moon is really cool to look at. I cannot see the rings of Saturn and I am getting very discouraged. I know where Saturn is so I know I'm look at the right thing. When I "focus" in, the object looks just like a dot - just like what I see with the naked eye.

As I am "focusing" the object appears bigger then as I focus, it gets smaller. I've tried the eyepieces with and without the Barlow lens. When I went away from the city, it didn't make a difference. The stars are still just dots. Of course away from the city I see more.

Am I doing something wrong? I researched different astronomy clubs but scared to make contact because I know so little and will look stupid. I called Meade and they said try a 9mm eyepiece with the 2x Barlow.

[SirThoreth]

I am an ameteur. I Have been trying to look at Saturn. I have a Meade 70EXT. THe eyepiece is 25mm. I bought a 6.4 mm eyepiece and a 2x Barlow lens.

The moon is really cool to look at. I cannot see the rings of Saturn and I am getting very discouraged. I know where Saturn is so I know I'm look at the right thing. When I "focus" in, the object looks just like a dot - just like what I see with the naked eye.

As I am "focusing" the object appears bigger then as I focus, it gets smaller. I've tried the eyepieces with and without the Barlow lens. When I went away from the city, it didn't make a difference. The stars are still just dots. Of course away from the city I see more.

Am I doing something wrong? I researched different astronomy clubs but scared to make contact because I know so little and will look stupid. I called Meade and they said try a 9mm eyepiece with the 2x Barlow.

Sounds like you might not be quite focused in properly, for starters.

OK, I just looked up the Meade EXT-70. Interesting scope. You've got a 70mm aperture, and a 350mm focal length.

OK, with a 350mm focal length, and that 25mm eyepiece, you're only going to get 14x magnification. With that low of magnification, you might not see Saturn's rings, as that's pretty low. With that Barlow, you're still only talking about 28x magnification.

The equation for magnification, BTW, is focal length of the scope divided by focal length of your eyepiece, so your 6.4mm eyepiece will give you a magnification of around 55x. At that power, you should be able to see the rings - I did through my scope at 50x last night. The Barlow would bump that up to around 109x (I rounded off, earlier), at which point you might be able to see the Cassini division in the rings (I could at 139x).

So, it might be that you're not quite focused in right. I know that when I first set up my new scope (for that matter, my very first telescope) a couple nights ago, I had that trouble. The Barlow, BTW, might also be throwing your focus off - I noticed that was an issue I was having when hooking up an extension tube for my camera to my scope. I'd sight in on the Moon again, and make sure you can clearly see the craters on the surface.

Note also that, at 109x, you're pushing the maximum your scope can handle. In theory, a scope can handle magnification equal to twice its apeture in millimeters, though, in practice, they usually don't quite reach that. So, that could be one of the problems, too, and why Meade recommended the 9mm eyepiece and the Barlow - that'd be around 78x magnification, a nice midway number, giving you decent field of view and good magnification.

OK, the stars - hate to disappoint you, but they're only ever going to show up as point sources. They're too far away to ever be anything else.

Another suggestion I'd have is to look at Jupiter. It's a nice, easy target, and I can see two cloud bands and even moons at only 50x. Galileo, remember, had a 30x instrument to work with when he started looking at Jupiter's moons. It'd be a good way to make sure you've got everything down pat before trying Saturn again. I tried Saturn first, and, after thinking I was on target, found only stars where I was looking - I wasn't sighted in right. I was, however, able to find Jupiter, even though my finder was off, I was on a camera tripod and not my better equatorial mount, etc. The next night, I used the right tripod and mount, lined up the finderscope using the moon, tried Jupiter, and then went after Saturn, much more successfully.

BTW, I just noticed - that was your first post. Welcome to the boards!

[dgruss23]

Sky&Telescope (http://skyandtelescope.com/observing/objects/planets/article_304_1.asp) has a nice article about observing Saturn.

[traztx]

It is normal for the objects to appear larger out of focus. A badly out of focus star looks like a large donut in reflector scopes. When focusing you should try to make the stars as tiny as possible.

As far as I can tell from the web, your scope has a focal length of 350mm. Therefore:

25mm eyepiece = 350/25 = 14x
25mm with 2x barlow = 28x
6.4mm eyepiece = 54x
6.4mm with 2x barlow = 109x

Theoretically, your scope should be able to resolve to 1.65 arc seconds. Saturn's observational size varies from 14.5 to 20.1 arc seconds. Since it is currently near opposition, the large size is closer to truth.

Therefore I don't believe it is beyond your scope's abilities to see a ring around saturn if you get a really fine focus. You will not be able to see the cassini division, though, but it'll be a cool shot nonetheless.

Some other objects that should look really pretty in your scope:
- Pleides
- The double cluster
- The hyades

Also don't be afraid to talk to local clubs. I am a member of the Texas Astronomical Society at Dallas, which has several hundred members and we love answering questions and throwing star parties (over 5 per month!). Bring your scope to your local star party and someone should be able to help you get a good view or let you borrow a nicer eyepiece if that is the problem.

[aurora]

Am I doing something wrong? I researched different astronomy clubs but scared to make contact because I know so little and will look stupid.

Every amateur astronomer I know is very friendly. That sounds trite, but at all the local and regional events I have attended, you couldn't ask for a nicer bunch of people.

Every astronomy club I know about welcomes newcomers. Many hold regular events especially for beginners!

Don't worry about looking stupid (you won't, you will just look like you are starting out), everyone starts out or started out as a beginner in every subject area. The more experienced members probably answer beginner questions all the time.

As to Saturn, you already have a number of answers, but in order to see Saturn's rings, you really need to get the magnification to well over 20x. So once you have the scope pointed at Saturn you will have to use your higher power eyepiece or put in the barlow. If it still looks like a point, then check to see if you really have it pointed at Saturn.

To check to see if the telescope is in focus, look at stars in the field. Stars should all appear as points.

[MoMo]

OK, a few quick questions for you seasoned astronomers:

1) Is a 2x Barlow Lens worth purchasing? Orion currently has one on sale for $27.95 (http://www.telescope.com/jump.jsp?itemID=253&itemType=PRODUCT&path=1%2C2%2C 6%2C25&KickerID=333&KICKER) and I was considering purchasing one.

2) What would you estimate my maximum magnification to be, based on the following specs:

- 1200mm focal length
- 254mm (10") reflector

According to my manual, 60 power can be used for every inch of aperture. That means that I could theoretically go up to 600x magnification, which seems a bit high. It then goes on to state that most observing should be done in the range of 20-35 power for every inch of aperture. This would drop the maximum magnification from 600x to 200x - 350x, which seems kinda low. Without a Barlow, the highest I can currently go is 300x. I'm hoping that 500x is acceptable because if I purchase the Barlow 2x it means I could use it with my 6.3mm thru 25mm eyepieces, rather than just my 20mm and 25mm eyepieces, which may affect my decision to purchase one. I didn't want to take the manual too literally, so I thought it might be a good idea to get second opinions from some of the more experienced folk who lurk here! :D

[SarahMc]

OK, a few quick questions for you seasoned astronomers:

1) Is a 2x Barlow Lens worth purchasing? Orion currently has one on sale for $27.95 (http://www.telescope.com/jump.jsp?itemID=253&itemType=PRODUCT&path=1%2C2%2C 6%2C25&KickerID=333&KICKER) and I was considering purchasing one.

A barlow is usefull if you don't have a wide variety of eyepieces. Personally, I prefer just to use an EP rather than a barlow (the more glass you have in the path, the more light you lose).

would you estimate my maximum magnification to be, based on the following specs:

- 1200mm focal length
- 254mm (10") reflector


The general rule of thumb is 50x your aperture in inches, so 500x. Be aware that reaching that magnification depends on everything being at it's best - seeing, transparency, collimation, your eyes, and the quality of the optics themselves. A more reasonable figure would be 250x for most of the time.

According to my manual, 60 power can be used for every inch of aperture. That means that I could theoretically go up to 600x magnification, which seems a bit high. It then goes on to state that most observing should be done in the range of 20-35 power for every inch of aperture.

That's reasonable.


This would drop the maximum magnification from 600x to 200x - 350x, which seems kinda low. Without a Barlow, the highest I can currently go is 300x. I'm hoping that 500x is acceptable because if I purchase the Barlow 2x it means I could use it with my 6.3mm thru 25mm eyepieces, rather than just my 20mm and 25mm eyepieces, which may affect my decision to purchase one.

Many objects you'll be viewing will require lower powers and wider fields of view. I routinely start off viewing at 80x, and then increase the power if the object and the seeing conditions allow it. I rarely ever exceed 200x, but there are fleeting moments when the conditions have allowed me to go as high as 500x. Usually those high powers are reserved for splitting double stars and planetary viewing. Most objects, like galaxies, clusters and nebula require much lower powers and wider fields of view. Don't get hung up on power. What matter is most is the contrast of the object and what you can resolve - making it "bigger" in the eyepiece usually isn't the answer for better views.

[aurora]

Many objects you'll be viewing will require lower powers and wider fields of view. I routinely start off viewing at 80x, and then increase the power if the object and the seeing conditions allow it. I rarely ever exceed 200x, but there are fleeting moments when the conditions have allowed me to go as high as 500x. Usually those high powers are reserved for splitting double stars and planetary viewing. Most objects, like galaxies, clusters and nebula require much lower powers and wider fields of view. Don't get hung up on power. What matter is most is the contrast of the object and what you can resolve - making it "bigger" in the eyepiece usually isn't the answer for better views.

I agree with what SarahMc said, good comments.

As you increase magnification, you also decrease brightness and at some point you just make things bigger and fuzzier and you see no more detail.

When I'm looking for deep space objects, I usually operate between 45 and 70 power.

Whether to use higher power depends on the object, the seeing and transparency on the particular evening, and the quality of the optics (and collimation). Find something interesting and try your different eyepiece combinations and see.

Then hope for that rare one or two nights a year when the sky is just perfect.

[milli360]

The moon is really cool to look at. I cannot see the rings of Saturn and I am getting very discouraged. I know where Saturn is so I know I'm look at the right thing. When I "focus" in, the object looks just like a dot - just like what I see with the naked eye.
If you can get it to focus that tightly, and you're using the barlow and/or the 6mm, you are looking at the wrong thing. I don't think that there is any other conclusion.

The Meade has an auto goto, right? However, that's not necessarily entirely reliable. I once went to a school function, where they were using a large 200mm Meade with goto, and they were using Polaris to align the scope. I could tell from six feet away that they weren't looking at Polaris. :)

Later, they found out the onboard computer chip had a Y2K problem which made it unusable for planets in this century--they had to order a replacement.

[skyglow1]

I am an ameteur. I Have been trying to look at Saturn. I have a Meade 70EXT. THe eyepiece is 25mm. I bought a 6.4 mm eyepiece and a 2x Barlow lens.


The moon is really cool to look at. I cannot see the rings of Saturn and I am getting very discouraged. I know where Saturn is so I know I'm look at the right thing. When I "focus" in, the object looks just like a dot - just like what I see with the naked eye.

As I am "focusing" the object appears bigger then as I focus, it gets smaller. I've tried the eyepieces with and without the Barlow lens. When I went away from the city, it didn't make a difference. The stars are still just dots. Of course away from the city I see more.

Am I doing something wrong? I researched different astronomy clubs but scared to make contact because I know so little and will look stupid. I called Meade and they said try a 9mm eyepiece with the 2x Barlow.

....OK, the stars - hate to disappoint you, but they're only ever going to show up as point sources. They're too far away to ever be anything else....


Correct me if I'm wrong but didn't the supergiant star Beteugeuse (bad spelling) appear to be a disc in the Hubble Telescope allowing us to calculate the diameter of the Star directly??

skyglow1

[milli360]

Correct me if I'm wrong but didn't the supergiant star Beteugeuse (bad spelling) appear to be a disc in the Hubble Telescope allowing us to calculate the diameter of the Star directly??
But SirThoreth was referring to Lsh14's telescope and such ilk, I think.

[skyglow1]

Correct me if I'm wrong but didn't the supergiant star Beteugeuse (bad spelling) appear to be a disc in the Hubble Telescope allowing us to calculate the diameter of the Star directly??
But SirThoreth was referring to Lsh14's telescope and such ilk, I think.

Yes, I think so too, never mind my comment.

skyglow1

[milli360]

They haven't been back yet to report on the retries, so Betelgeuse is fair game. Is that the only stellar disk that has been resolved?

[Kaptain K]

A few stars (including Betelgeuse) have been resolved, but not with Hubble. They were imaged using optical interferometry.

[traztx]

1) Is a 2x Barlow Lens worth purchasing? Orion currently has one on sale for $27.95 (http://www.telescope.com/jump.jsp?itemID=253&itemType=PRODUCT&path=1%2C2%2C 6%2C25&KickerID=333&KICKER) and I was considering purchasing one.


Be careful. If you are using a diagnol you might need to get a "shorty" barlow. Also since this adds more glass to your view you should save up for the better versions.

There are other benefits from using a barlow:
- If the sky is nice and steady, then you can get a finer collimation.
- Use with bigger eyepieces to enjoy their better eye relief vs using the smaller eyepiece for the same mag.

I find it harder to get a good focus at highest power, so I got a couple of clamps at Home Depot to add handles to my focuser. This was cheaper than replacing it with an electronic one. I clip them so that they stick out on both sides to maintain balance while giving me more leverage.

[kookbreaker]

1) Is a 2x Barlow Lens worth purchasing? Orion currently has one on sale for $27.95 (http://www.telescope.com/jump.jsp?itemID=253&itemType=PRODUCT&path=1%2C2%2C 6%2C25&KickerID=333&KICKER) and I was considering purchasing one.


Be careful. If you are using a diagnol you might need to get a "shorty" barlow. Also since this adds more glass to your view you should save up for the better versions.
.

That actually is a shorty barlow the link leads to.

The better barlows will usemore glass to provide a better image. The minor drop in light transmission is more than made up for by improved clarity.

[ChesleyFan]

OK, a few quick questions for you seasoned astronomers:

1) Is a 2x Barlow Lens worth purchasing? Orion currently has one on sale for $27.95 (http://www.telescope.com/jump.jsp?itemID=253&itemType=PRODUCT&path=1%2C2%2C 6%2C25&KickerID=333&KICKER) and I was considering purchasing one.

2) What would you estimate my maximum magnification to be, based on the following specs:

- 1200mm focal length
- 254mm (10") reflector

According to my manual, 60 power can be used for every inch of aperture. That means that I could theoretically go up to 600x magnification, which seems a bit high. It then goes on to state that most observing should be done in the range of 20-35 power for every inch of aperture. This would drop the maximum magnification from 600x to 200x - 350x, which seems kinda low. Without a Barlow, the highest I can currently go is 300x. I'm hoping that 500x is acceptable because if I purchase the Barlow 2x it means I could use it with my 6.3mm thru 25mm eyepieces, rather than just my 20mm and 25mm eyepieces, which may affect my decision to purchase one. I didn't want to take the manual too literally, so I thought it might be a good idea to get second opinions from some of the more experienced folk who lurk here! :D

1) I have a shorty barlow but rarely, if ever, use it. I'd rather spend the money on a good quality eyepiece. The shorty barlow also has a problem with blackout on low power (specifically, my 25mm) eyepiece-- that is, if you don't position your eye just right in the eyepiece, you won't see anything at all.

2) I have a 8" reflector, so theoretically I can push it to 480X. In reality I rarely go beyond 200-250X for planets, and about half that for most deep sky objects. If I had an apo, though... :)