Question about Bushnell Optics

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I have a 4.5 inch reflector 500mm focal length. I know it is basic but a planetary eyepiece should give a reasonable yet small image of saturn. I have bought a 4mm Celestron plossl for this. The eyepiece will not focus. The eyepiece hits the stop at the bottom of the focuser and when I wind it in it hits the end of its range just before the image comes in to focus. I am gutted as I was looking forward to a view with the higher quality optics. does anyone have any suggestions to remedy this. I can only think of shortening the tube on the plossl. Which seems longer than necessary.

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If you pull the eyepiece slightly out of the focuser can you then come to focus? If you can just lock down the eyepiece at that point -- or buy this:

http://www.skiesunlimited.net/index.php?CategoryID=132

Posted on Apr 07, 2011

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1 Answer

Does it make a difference to your viewing if you have a bigger length telescope or a smaller one


Focal length not physical length would better answer your question. Shorter focal length scopes have a lower power but wider view per size of eyepiece.
BUT!
Tasco telescopes are basically junk telescopes. Any telescope from Celestron, Meade, Orion, Explore Scientific or Televue (to name the more popular) will give you a superior view compared to the Tasco.
A 60mm scope has the maximum magnification of 225x (under perfect sky conditions. I suggest a small, short tube reflector in the 4 inch range. They are lightweight, have much more light gathering power (more important than magnification) and easy to set up.

Oct 12, 2012 | Bushnell Tasco Telescope Galaxsee 525x60mm...

1 Answer

A lens is missing


This telescope uses 1.25 inch eyepieces. Comes originally with a 20mm and a 4mm (probably cheap modified acromats) The 4mm would exceed the maximum practical magnification. 50x per inch. Many eyepieces available on Ebay and telescope vendors. If the 20mm is missing, buy a 20mm Plossl. I prefer other designs focal lengths under 12.5mm because of the eye relief. Agenaastro makes great, inexpensive ($55). I like the Sterling Plossls from Smartastronomy too Eyepieces for planetary viewing I suggest the 5.2mm for your high power or a TMB planetary (Astronomics has them for $50 Get the 5 or 6mm

Clear Skies!

Oct 04, 2012 | Bushnell NorthStar 78-8831 (525 x 76mm)...

1 Answer

NATIONAL GEOGRAPHIC TELESCOPE NG76AZ where can i get a solar filter and additional lenses etc for above 76mm telescope


Do NOT attempt to look at the Sun through a solar filter! These can crack from the heat and you will be blinded instantly.

Most telescopes use a standard fitting eyepiece with a 1.25 inch outside diameter barrel. You can measure the mount where the eyepiece goes to make sure that yours is this size, then search on eBay or Amazon for "1.25 eyepiece" and you will find many available. None of these will be made by National Geographic, but any make will fit.

The other variable will be the focal length of the eyepiece, which is what determines it's power. The power of the scope will be the focal length of the main objective divided by the focal length of the eyepiece, so a 9mm eyepiece will give a higher magnification (and be dimmer and harder to focus and find objects) than a 20mm eyepiece. It is usual to have two or three different focal length eyepieces for viewing different objects.

You will find a large variation in prices, which is partly due to the difference in quality and type of construction of the eyepieces. Kellner eyepieces are simple and cheap, whereas Possl or orthoscopic ones are more complex and cost more. There are reasons why people will pay more for the better eyepieces. Avoid eyepieces marked with the letters "H" or "SR" before the focal length.

Jan 20, 2011 | National Geographic 76AZ (525 x 76mm)...

1 Answer

The eye piece lens is missing. How do i find the model number of the telescope to order a new eye piece and a manul for this telescope


Most telescopes use a standard fitting eyepiece with a 1.25 inch outside diameter barrel. You can measure the mount where the eyepiece goes to make sure that yours is this size, then search on eBay or Amazon for "1.25 eyepiece" and you will find many available. None of these will be made by "Edu-Science", but any make will fit.

The other variable will be the focal length of the eyepiece, which is what determines it's power. The power of the scope will be the focal length of the main objective divided by the focal length of the eyepiece, so a 9mm eyepiece will give a higher magnification (and be dimmer and harder to focus and find objects) than a 20mm eyepiece. It is usual to have two or three different focal length eyepieces for viewing different objects.

You will find a large variation in prices, which is partly due to the difference in quality and type of construction of the eyepieces. Kellner eyepieces are simple and cheap, whereas Possl or orthoscopic ones are more complex and cost more. There are reasons why people will pay more for the better eyepieces. Avoid eyepieces marked with the letters "H" or "SR" before the focal length.

There is an excellent website for beginner telescope users at THIS LINK

Jan 20, 2011 | Edu-Science (10166) Telescope

1 Answer

Im trying to find an eyepiece for a Meade model#114EQ-DH telescope.


Most telescopes use a standard fitting eyepiece with a 1.25 inch outside diameter barrel. You can measure the mount where the eyepiece goes to make sure that yours is this size, then search on eBay or Amazon for "1.25 eyepiece" and you will find many available. Some of these will even be made by Meade, but any make will fit.

The other variable will be the focal length of the eyepiece, which is what determines it's power. The power of the scope will be the focal length of the main objective divided by the focal length of the eyepiece, so a 9mm eyepiece will give a higher magnification (and be dimmer and harder to focus and find objects) than a 20mm eyepiece. It is usual to have two or three different focal length eyepieces for viewing different objects.

You will find a large variation in prices, which is partly due to the difference in quality and type of construction of the eyepieces. Kellner eyepieces are simple and cheap, whereas Possl or orthoscopic ones are more complex and cost more. There are reasons why people will pay more for the better eyepieces.

Jan 18, 2011 | Meade Infinity 114EQ-DH Telescope

1 Answer

Purchased a tasco 675 luminova telescope and the front lens was missing. Where can i get one from?


I assume you mean the eyepiece. This telescope uses 1.25 inch eyepieces. Maximum magnification is 400x on a perfect seeing night.
I would start with a 20mm plossl which would give you 33x. Enough to see the moon and Jupiter/Saturn. If you get interested, then buy more eyepieces and most important a moon (neutral density) filter.
telescope focal length (675)/ eyepiece focal length = magnification
Good places for eyepieces are Ebay, Astronomics, Smart Astronomy

Oct 16, 2010 | Tasco Luminova 40114675 (675 x 114mm)...

1 Answer

I have a tasco #302003, it is a reflector model. Obj diameter 76mm, focal length 700mm. Could I see the moon surface? Which eyepieces do I have to use for it? Many thanks in advance.


Yes you can see the moon and the bright planets. It's very simple to calculate magnification.

Divide the focal length-- 700mm by the number written on the eyepiece. So if it is a 25mm eyepiece then:

700 divided by 25 = 28 power

If it is a 10mm then 700 divided by 10 = 70 power.

Either one will give you a good view of the moon. Your scope has about a 3 inch mirror so the maximum possiible magnification if everything is PERFECT including the sky is about 50 times 3 or 150 power.

Aug 09, 2010 | Optics

1 Answer

Not seeing a larger, more detailed image w/ Bushnell 78-8850.


Currently the rings of Saturn are nearly edge on so you won't see any details in them. Shortly the rings will appear edge on and the ring will disappear completely for a few months. Gradually, they will return and angle more towards Earth at which time you will be able to see some of the ring details.

There are many factors that can reduce your ability to see planetary detail. I had my Celestron 200mm out the other night looking at Saturn but saw no details because the atmosphere was too unstable. There are also limits to what a telescope can realistically view.

There is a general rule of thumb that states you can expect to view 50x per inch of aperture. Your telescope has roughly 5" of aperture. 5 times 50 equals a maximum of 250x. However, this is a guideline. On bad nights like I had you'll never reach that 250x since objects will appear blurry or unstable. On good nights, you can exceed this.

You can calculate your telescope power by dividing your telescope focal length by the focal length of the eyepiece ( that 4,9,20mm number).

An excellent object to look at when it comes back in view is Jupiter. It's always interesting and you can see four of it's moons.

Good luck and clear skies.

-jodair

Mar 30, 2009 | Bushnell North Star 78-8850 Telescope

1 Answer

Eyepieces lost


You did not mention your telescope make and model so:
1. measure eyepiece holder. Determine of you use .965in. or 1.25in. diameter eyepieces. If you use .965 eyepieces you are limited in choices. HANDSONOPTICS.COM carries nice Plossls. SURPLUSSHED.COM. sells .965 moon filters and cheaper eyepieces. If you have a 1.25 eyepiece holder, the skies the limit on eyepieces. Check Ebay plus other sites.
2. Determine the focal length of the eyepiece you want to use. As a rule, your scope can magnify 50x per inch of aperture although looking at just the moon, you can stretch that a bit. For example, a 80mm reflector (3.1 in). x 50 = 155x max. magnification (must be a perfectly clear night)
So now find the focal length of the scope (stamped/labeled somewhere) Typical refractor is 700mm. For maximum power (155x) it is: focal length of telescope/focal length of eyepiece = magnification. Or FL (scope)/ magification= FL eyepiece. 700/155= 4.5mm. This size will have terrible eye relief unless you spend $$$$$. Suggest a 10mm eyepiece which gives 70x power and a great view of the moon and planets

Nov 15, 2007 | Tasco Luminova 40114675 (675 x 114mm)...

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