Lens or Barlow Lens Help

[lighty89]

North Star Mars 76RDF 700x76mm (3") Newtonian Reflector kit

I have that telescope, I know its quite a starter scope, but, I am a starter lol. I have seen some good sights through it, like the Moon and Jupiter with its 4 moons!

But, I have problems zooming in tonight and the other night on the moon, I dont know if it could be the lenses I'm using or the atmospheric conditions, or both. I was using the 4mm lens, and it still wasnt very close at all, so I added the Barlow to the 12.5mm I got and it was really blurry.

Do I need new lenses?

[John]

According to the advert your scope is supplied with the "H" or Huygens type eyepieces. These are a rather poor design in my opinion and will not be doing much to show off what your scope is capable of.

It would be worth investing in 2 or 3 eyepieces of the plossl design (in the 1.25" fitting of course) - you can get these for around £20 each and they would be an investment for any future scope you might purchase. Focal lengths such as 25mm, 12.5mm and 6mm would be useful in your scope.

Likewise I suspect the barlow lens is poor quality as well so I'd not bother using that as it will only make matters worse.

Hope that helps,

John

[Merlin66]

With a 4mm eyepiece you are already getting about x228 magnification!

The limit for a 3" scope is realistically more like x150....

Better eyepieces will improve the view, but I think you may have to come to terms with the limitations of your telescope.

[lighty89]

Thanks for your replies!

Yeah I see your point, would it be worthwhile me getting the better eyepieces then?

What sort of things can I expect to see at around 150x?

[barkis]

I know you are a novice, and probably bought this instrument to satisfy a curiosity, but coupled with it's limited light gathering capability, and the H eyepieces John has already referred to, I would urge you to consider carefully before spending more money on this telescope.

Merlin too has describe the limitations, and these will still exist even with higher quality eyepieces. There is limit to what magnification this instrument can deliver. Using high powers will reduce the image quality, simply because of the limiting size of the mirror. Another point, at high magnifications, and object would probably dance all over the place every time you touch the focuser, and perhaps even move out of the field of view altogether.

Of course, if you intend to acquire another telescope with a larger mirror or lens, then any eyepieces you buy will be fine with it.

Can I advise you to seek help on this forum before you commit to spending any more of your money. It will help to ensure that your next choice will be a good one.

Good Luck.

Ron.