Telescopes

Archive for the ‘ETX Telescope’ Category

I use a Zhumell dobsonian 10" reflecter telescope for most of my viewing.

The accessories use mainly are

1.Baader hyperion 5mm

2.Zhumell plossl 9mm

3.Meade plossl 26mm

4.Zhumell plossl wide view [2in.] 30mm

5. TeleVue 2x barlow

I recently got my TeleVue barlow and used it with my 5mm baader hyperion and used them to view The moon, Mars, Saturn, Venus, and Sirius. The views were amazing. The mag. was brought up to around 500x and I would have to say that its hard to even pick my favorite view through the TV. barlow attached to my Baader 5mm. They work great together and would recommend them both to anyone serious about viewing the night sky.

What i am curious about is viewing Uranus, Pluto, and Neptune. I know that I will definately be able to see Uranus, Mercur and Neptune. But I am wandering what they will/should look like through my Telescope at around 500x. I have a feeling that Uranus will be the easiest to view out of these three due to it being larger and closer to the earth than Neptune and it being close to Jupiter and thus being easier to find. How big will Uranus appear at around 500x?

and Neptune and Mercury? I know mercury looks like a brightish star right now close to Venus and a little bit lower. I havent had a chance to see it yet because of trees and houses in the way.

As for Pluto my theory on how I would end up seeing it would be by using my Meade ETX-80 to locate it, look through my eyepiece to recognize that patch of the sky visually ad then point my 10" dob. to that point of the sky. ill I see pltuo as a SMALL round dot? or will it appear as a bright star:? or is the only way to tell it apart from the stars to set a camera up on a big telescope and let it record/follow that patch of sky over a matter of a few hours or so and the dot that moves differently than the other stars over the time period is Pluto?

Let me know what you think/ know.

I am really surprised that you are able to use 500x…I rarely find that the atmosphere will support more than about 300x, and that’s only on exceptional nights.

Uranus and Neptune will appear as tiny blue or blue-green featureless disks. On Mercury you should be able to detect the phase and perhaps a dark shading or two.

Pluto will be a point source, looking exactly like a 13th magnitude star. Rather than use the ETX, I’d recommend using a good planetarium program like Starry Night to plot Pluto’s position against stars of similar brightness. The chances of finding enough stars visible in an 80mm scope to guide you to Pluto is pretty remote. You can’t trust the star catalogs in planetarium programs at that faint a magnitude: numerous stars are often missing. The only way to be sure you’ve seen Pluto is to plot its position from night to night on a deep star chart.

I got a Meade ETX-60 refracting telescope for Christmas. The scope included 9, 12, and 25 mm lenses. Should I be able to see Saturn clearly with this scope? If so, what am I doing wrong? No matter which lens I use, when I get it focused in, it seems like I am looking at the same little pin point of light that I could see with my naked eye.

The ETX-60 has only a 60mm aperture and a focal length of 350mm.
A 25mm eyepiece gives 350/25 = 14x
A 12.5mm eyepiece gives 350/12.5 = 28x
A 9mm eyepiece gives 350/9 = 39x
To see Saturn as a decent disk you need around 60x at the moment. The rings will be almost impossible with your low powers on a 60mm telescope of average quality because they are almost edge on.
If you have good eyes and good optics you can tell Saturn isn’t a star with 10×50 binos. With 20×50 when the rings are wide you can see them quite well. Not at the moment, because they are almost edge on.
Here is what Saturn looks like through bigger telescopes. The bottom one is 400x on a 75mm aperture Telescope. See how dark it is? A 60mm collects a lot less light than a 75mm.
No chance of using powers high enough to see Saturn as a big disc
http://www.rocketroberts.com/astro/scopeview.htm . . . .
The ETX-60 is good for star clusters and general looking around to admire the view and for low to medium power views of the Moon, and of course it’s quite good for wildlife where high powers are much less useful. Around 60x is the maximum you can use for terrestrial viewing and for low angle sky views…near the horizon….because of the thicker air and turbulence. At high elevations the air is much better to see through.
39x for a terrestrial scope is just nice for your higher power and the 28x is quite comfortable to use. Not too powerful to follow things when they run or fly and bright enough to use in poor weather.
That’s the score for the ETX-60….it’s not for planets or faint nebulae.
Here is a real user’s guide…not the Meade one.
http://novac.com/resources/reviews/etx60.php . . . . . .
You can use a 2x or 3x Barlow lens to increase the power but doubling the power makes the image 4x darker and tripling it makes it 9x darker.
It goes by the inverse square law. Twice the diameter of disc is four times the area that the same amount of light (collected by the 6omm objective) is spread over.
Three times the diameter is nine times the area.
With only 60mm aperture a Barlow lens is not a good way to go except for very bright objects like the Moon.
At 120x on a 60mm you’ll have such a dark image of Saturn you’ll be struggling to see anything.

I’ve been offered a Meade ETX-90 for 200 dollars with the alt mount and a few lenses. However, I’ve seen from reviews and pictures before on this same telescope where they were all GoTo telescopes. This one has no ports on its base for the sort, so I am a little skeptical if this is an older, but still equal telescope, than its computerized partner.
I’ve been looking for weeks for a amateur Telescope that I can afford but not worthless. Should I go for it?
What strikingly relevant advice. Ive been looking for binoculars for weeks, but nobody has a pair they are willing to part with. I also have set the Orion XT10 as my main goal of a telescope, as I’d like a dobsonion, but 500 dollars is out my range for the next few months. That’s why Ive been looking for used telescopes.

All I can say is wait to get the funds for the XT10,it is a fine instrument and well worth the wait.
Join a club,members are always willing to help and you can get some eyepiece time at a star party or two.
Wally