eyes pieces question

[william martin]

Well it came and I just put it together.

Now it cames with  eye pueved

The prisum part

1_barlo 

1. Meade eyes piece

And the eyes pieces

 

So with eye piece to use to see planets?

Which piece to see detail of the moon?

What eye piece see stars with?

This telescope is for both ways

Outer space and land

Anyone like to help out ?

I'm listening..

[DRT]

Hi William,

Which telescope have you bought?

What are the focal lengths of the eyepieces that came with it? (10mm? 20mm? 25mm? etc)

If you tell us what you have we should be able to help you.

Derek

[Mak the Night]

Can you be more specific about your telescope and eyepieces? Make, aperture size, focal length etc. Usually, the eyepieces with shorter focal lengths are for planetary/lunar high magnifications and the eyepieces with longer focal lengths give lower magnifications. Stars, star clusters and other objects such as nebulae are usually observed with lower magnifications. The Barlow lens is inserted between an eyepiece and the telescope to increase magnification (normally by a factor of 2x).

The Moon and most planets need at least around 130x - 150x magnification to see any real detail. For sweeping star fields or looking at Messier objects anything from around 30x to 70x can be effective.

If you look at the collection of eyepieces above they range from a 40mm Plossl (top row, extreme left) to a 6mm orthoscopic eyepiece (bottom row, extreme right). The first four on the top row, depending on the telescope I'm using, tend to be used more for stars, deep space objects, star clusters and the like. Whereas the smaller focal length eyepieces on the bottom row are used predominantly for lunar/planetary viewing.

[Dave In Vermont]

Okay, I'll bite -

Your telescope is an 80mm F/5 achromatic refractor. This is known as a 'fast' telescope in that it reaches focus in a short distance. To find the Focal-Length, the '5' tells you that the 'focal-length' is 5X the aperture - 80mm. So 5 X 80mm = 400mm.

Now to find how much magnification an eyepiece will give you in your telescope, you divide the 'focal-length' ( FL ) by the FL of the telescope - 400mm. So if you have a 20mm eyepiece ( EP ): 400mm / 20mm = 20X.

For viewing planets, a high magnification is often favored to show details of the planet's surface (Mars is a good example) or upper-atmosphere on, say, Jupiter & Saturn. For 'Deep-Space Objects' (DSO's) such as extended nebulae (Gas - Clouds) like The Veil in Cygnus - a lower magnification would usually be chosen to get the widest 'Field-of-View' ( FOV ) possible to be able to fit the object into your eyepiece ( EP ). Such as a 40mm EP to give you 10X and a nice, wide FOV.

Other types of DSO,s such as Ring Nebulae like M57 in Lyra, a narrow FOV can be used.

I'll let others fill in the blanks! My fingers hurt.....

Dave

[Putaendo Patrick]

Looking at your earlier post, your telescope is a Meade Infinity 80mm AZ Refractor with a focal length of 400mm.

In addition to the diagonal, you probably have three eyepieces and a x2 Barlow. The eyepieces should be marked 26mm, 9mm and 6.3mm. In your telescope these will give magnifications of x15, x44 and x63 respectively. The Barlow which goes between the diagonal and the eyepiece will double the magnification of any of the three eyepieces.

I would start observing the Moon and planets with the 9mm eyepiece, then the 6.3mm, then with the eyepieces plus the Barlow. The planets will appear small, even at the maximum x126, but you should easily see some detail. Saturn with its rings and Jupiter with its moons are unforgettable!

Your viewing will also depend on the quality of the eyepieces and Barlow - don't expect too much.

[Knighty2112]

Might help to know which actual telescope you have got, and what sizes are the eyepieces (EP's) that came with it?

In general for planetary and lunar work then higher magnification EP's are used; 12mm down to 4mm sometimes depending on your telescope. For stars you can use 32mm to 15mm EP's for wider field views. For close up on binary stars you can use the same kind of EP's that you use for planetary & lunar work.

Most basic scopes comes with a 20mm & 10mm EP. Also, some come with a 2x or 3x Barlow lens, which will double or triple the magnification of any EP used with it. A 20mm EP used with a 2x Barlow will become in effect a 10mm EP, & a 10mm EP will become a 5mm EP. If it is a 3x Barlow  20mm becomes approximately a 6.5mm EP, & a 10mm EP becomes in effect approximately a 3.5mm EP which mostly gives too high a magnification for any good astronomical views.

One thing to be aware of though; the higher the magnification you use in your scope the dimmer the views become, so again depending on the size of the main lens/mirror of your scope there will be a limit to the magnification your scope can handle. In general this is 2x the diameter of your main lens/mirror, so if you have a 70mm main lens or mirror then the maximum theoretical magnification you can get from such a scope is 140x. With a 120mm lens/mirror the max magnification becomes 240x, so higher powered EPs ca be used if you have a larger lens/mirror. 

[Dave In Vermont]

80mm F/5 Achromatic-Refractor is what he's got. And here's a manual for these:

Meade Infinity-series Manual.pdf

This may help -

Dave

[william martin]

There is a front cover on my scope looks like dust cover but it says it is focus cover in the middle , the small cover is in the center

.

Note it says this scope moves with earth's rotation....

 

Oopd I fell in love my scope lol

[Dave In Vermont]

Do you mean that the lens-cover has a smaller cap covering a smaller, round-hole? If so, this can be used for when you are viewing very bright objects such as the Full - Moon and the Sun (ONLY WITH A PROPER SOLAR-FILTER!! TALK WITH US FIRST!!). A smaller aperture will help to reduce the glare, and these sort of objects don't require lots of light to see them well.

Dave

[william martin]

OK it says in the instructions it is dew shade but it great dust cover.

In cleaning lens if needed  rubbing anchol is used instead of window clearer.

I use rubbing anchol for lens glass slides and slip covers on my omax  microscope.

 

 

So tonight take the cover off right?

[Dave In Vermont]

Please come to us BEFORE you decide to 'clean the lens.' There are specific guidelines & materials to use AND not to use. The objective (lens) of astronomical-telescopes are coated with very fine and delicate coatings. And they should ONLY be cleaned if absolutely necessary. A little dust or such won't affect your viewing in the least. Damaging the coatings certainly will.

Yes you would remove the end cap on the scope. Heck - I'll take a photo.....

Alright, here is my ST80 F/5 scope with it's lens-cap on:

 

And with the lens-cap off:

 

And the lens-cap itself showing the smaller opening in the cap:

 

So unless you're Superman and have x-ray vison, you need to remove the lens-cap at night to see anything through the telescope.

Until later -

Dave

[william martin]

Ok,  so blow OE brush the dust off. Than use lens cleaning paper.

Ughm  so where do put my Barlow lens at?

Top of the prisum piece or the bottom.of the prisum piece or into the scope it self.

 

This very informative site. Smiles....

[Putaendo Patrick]

3 hours ago, Putaendo Patrick said:

The Barlow which goes between the diagonal and the eyepiece will double the magnification of any of the three eyepieces.

I think technically the diagonal may also be known as the "prisum piece"

[Mak the Night]

The Barlow is usually placed into the focuser or diagonal then the eyepiece placed in the Barlow.

However, the Barlow may be placed between the diagonal (prisum piece) and the telescope. This does change the magnification somewhat though supposedly. I don't know as I don't actually do this myself as it's far too complicated for me to work out. And besides; I've had brain damage so I try to keep complicated mathematics out of my stargazing as a rule.

I have a few Barlows.

[william martin]

Thank you.

So what about moon filters why use them? The moon is not bright like the sun.

[Putaendo Patrick]

Although the Moon will not damage your eyes (unlike the Sun which will), the glare can be uncomfortable, especially near Full Moon and especially in larger aperture telescopes. Also if you are switching between the Moon and other targets, planets for example, filters will conserve your night vision. People seem to have different levels of tolerance and quite a few people here don't use them at all. If you're thinking of buying a Moon filter, try with sunglasses first and see if the difference is an improvement for you.

[Dave In Vermont]

A 'Moon-Filter' helps make the contrast between the lit and unlit areas of the Moon more pronounced. It is in these areas that you can see the sharpest details stand out. This area of the Moon, which changes as the Earth & Moon move in their orbits, is called the Lunar-Terminator. Or just the 'terminator.' So this is what they may help make even more sharp. A variety of different filters can be used for our Moon.

 

Dave - Resident Filter-Nut

PS - Mak the Night is our Resident Barlow-Nut.

[william martin]

It be blue filter, the sun filter would have to be made from the glass that arc welder's mask is made from.

But they say use a piece of white cardboard and have your telescope project the image on there  , lot safer

[Putaendo Patrick]

William

Please, please, please only use a special astronomy filter bought from a respectable astronomy dealer. Get a solar filter which will fully cover the front of your telescope (not the eyepiece).

Never take short cuts or use items which are not designed specifically for solar observing. You may easily end up permanently blinding your eyes, it really does only take seconds and you will be maimed for the rest of your life.

There is some advanced equipment, such as Herschel wedges, which employ different systems - but these cost a lot and are only for specialists who know exactly what they are doing.

Projection is safe for you, but if your refractor telescope has plastic parts such as the focuser, it may cause serious and expensive damage to the scope. Never attempt projection with a telescope that uses mirrors.

Be very careful!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Dave In Vermont]

Actually, it only takes 1/200th. of a second to cause permenant damage to your eye with an un-filtered telescope. But it takes 1/20th. of a second for your eye-blink reaction to occur.

Please do not prove this true -

Dave

[william martin]

I only interested in outer space , I have no unrest in the sun.

 

[Mak the Night]

Astronomical filters and their utilisation are highly subjective, and most people don't agree on anything about filter use.

Below: Baader Neodymium (extreme left) and some Wratten Blue 80A and 82A Light Blue filters.

I generally won't discuss filters on this forum anymore, but I find that the most useful general filter, particularly for lunar observing, is a neodymium filter. I tend to prefer the Baader Neodymium.

Orange and yellow filters can often be used effectively with certain conditions and particular targets. They can be useful observing the Moon in twilight/daylight conditions. Yellow-Green filters are good for revealing features on Mars and enhancing aspects of Saturn. The 80A Blue is often used for observing Jupiter. Different coloured filters are used for a variety of objects.

The only way to know if particular filters work well for you is to try them yourself. If I had to recommend three filters they would be:

1/ A neodymium filter.

2/ A blue filter.

3/ A yellow-green filter.

Of course, YMMV.

[Stu]

17 minutes ago, Mak the Night said:

Astronomical filters and their utilisation are highly subjective, and most people don't agree on anything about filter use.

Below: Baader Neodymium (extreme left) and some Wratten Blue 80A and 82A Light Blue filters.

I generally won't discuss filters on this forum anymore, but I find that the most useful general filter, particularly for lunar observing, is a neodymium filter. I tend to prefer the Baader Neodymium.

Orange and yellow filters can often be used effectively with certain conditions and particular targets. They can be useful observing the Moon in twilight/daylight conditions. Yellow-Green filters are good for revealing features on Mars and enhancing aspects of Saturn. The 80A Blue is often used for observing Jupiter. Different coloured filters are used for a variety of objects.

The only way to know if particular filters work well for you is to try them yourself. If I had to recommend three filters they would be:

1/ A neodymium filter.

2/ A blue filter.

3/ A yellow-green filter.

Of course, YMMV.

The Neodymium filter is an excellent filter for the Moon, Jupiter and Mars. No reason not to discuss filters Mak.

[william martin]

So many colors so many uses

Just as much with my microscope

[Dave In Vermont]

9 hours ago, Mak the Night said:

Astronomical filters and their utilisation are highly subjective, and most people don't agree on anything about filter use.

Below: Baader Neodymium (extreme left) and some Wratten Blue 80A and 82A Light Blue filters.

I generally won't discuss filters on this forum anymore, but I find that the most useful general filter, particularly for lunar observing, is a neodymium filter. I tend to prefer the Baader Neodymium.

Orange and yellow filters can often be used effectively with certain conditions and particular targets. They can be useful observing the Moon in twilight/daylight conditions. Yellow-Green filters are good for revealing features on Mars and enhancing aspects of Saturn. The 80A Blue is often used for observing Jupiter. Different coloured filters are used for a variety of objects.

The only way to know if particular filters work well for you is to try them yourself. If I had to recommend three filters they would be:

1/ A neodymium filter.

2/ A blue filter.

3/ A yellow-green filter.

Of course, YMMV.

I'll only add this to what Mak has so well stated:

If you only ever buy ONE colour-filter, the No. 80A Blue has been rightly called: The Swiss-Army of Filters, as it's useful for so many things. As for more specific filters go, the Baader Moon & Skyglow Neodymium-Filter, as Mak suggested (it's often just called the 'Neodymium-Filter'), is the one I'd endorse as well.

Red, Green, and Blue Skies Above,

Dave