Help with new eyepiece

[CosmicConnor]

Hey. I just bought a TV 5mm Nagler and was testing it today viewing some things terrestrially. This is my first 'premium' EP and I'm really excited about it but I have a few questions.

I have this starter scope a Celestron 127mm Newt reflector. This 5mm EP pushes the magnification to the theoretical limit of 200x. Is this why the image is dimmer? I had read that this happens and also does the dimmer images cos the squiggly lines/floaters that you see in your eye when looking through the EP? For some reason with the Nagler I get this more intensely than compared to my 8mm, even when I use a 3x barlow on my 8mm I still don't get it as bad as with the Nagler.

I don't want to sound ungrateful for this EP but I'm starting to wonder if its too strong my telescope.

[fatwoul]

Eyepieces remain a mystery to me (I'm mostly interested in imaging), but I am trying to work them out.

The only bit I can help with is the floaters thing. I've found that floaters are more visible in dimmer, uniform fields of light. I suspect that as the light gets brighter, the floaters simply become washed out of view by the excess light. They're always there, and as I understand it, some people get them more than others.

[John]

I have the Nagler Type 6 5mm and find it an excellent eyepiece in a wide range of scopes. Your scope should be OK with 200x - my 102mm refractor certainly is on decent nights.

I also have some floaters in my observing eye - I don't notice them any more with the 5mm Nagler than other eyepieces however when I use a barlow lens they become much more apparent.

Naglers do take some getting used to with regard to eye positioning.

What might be having an effect though is the optical design of your scope. I believe the Powerseeker 127 is compact newtonian that has a correcting lens element at the bottom of the eye piece drawtube which allows the scope to achieve it's 1000mm focal length in a compact design.

I can't be 100% sure but I do wonder if this extra lens element, when used in conjunction with the Nagler design (which also uses an amplifying lens group at the bottom of the chrome eyepiece barrel) is causing, or at least emphasising, some of the issues you describe.

I can only say that I've found Nagler Type 6's to be superb eyepieces (I have 4 of them) but it's just possible that they are not entirely happy with that particular scope design.

[CosmicConnor]

Okay well I might put my current telescope up on ebay and then use the money with some of my savings to buy another one. I impulsively bought this telescope without putting in the research but now I can take the time to investigate a new 'scope that will compliment my new EP.

Thanks for the great replies

[fatwoul]

Okay well I might put my current telescope up on ebay and then use the money with some of my savings to buy another one. I impulsively bought this telescope without putting in the research but now I can take the time to investigate a new 'scope that will compliment my new EP.

Thanks for the great replies

If you decide to sell it, it might be worth holding out until you have enough posts to advertise it here. I think you need 50. That way, you can use the time to research, be sure you really want to sell it, and know what scope you would prefer.

Also, I suspect that there is far less chance of you getting ripped off here as opposed to eBay, partly because most SGL members seem like nice people, but also because this is their home turf, and they'd be hurting their reputations if they fleeced a newbie.

That's what I'm counting on when I look through the classifieds, anyway!

[ronin]

If you are collecting 127mm dia of light and shoving that light into an image magnified 200x then yes it will be dimmer then if you shove it into an image magnified only 100x. 4 times dimmer by area.

You collect a fixed amount of light you cannot spread it out into a bigger image without it becoming dimmer.

[great_bear]

The squiggly lines are due to having a small "exit pupil" at high magnifications. When the aperture in mm of a scope drops to about 85% of the magnification figure, floaters become more noticeable.

Also, these low-cost, small reflectors don't take very high magnification very well compared to refractors or Maks - so with that scope you're certainly not seeing the best that this EP can offer.

[CosmicConnor]

If you decide to sell it, it might be worth holding out until you have enough posts to advertise it here. I think you need 50. That way, you can use the time to research, be sure you really want to sell it, and know what scope you would prefer.

I think this is a good idea but I love selling on ebay its been something I have been doing a lot lately. I will sell it on there then with the money and some savings I will use this forum to research the perfect scope for my budget. I won't be using ebay to buy telescopes or anything just to sell. The reason I'm so hellbent on selling this scope is cos I have seen so many greater ones for the same price in telescope dedicated sites since buying it. This telescope just doesn't do the Nagler any justice. I really feel stupid for being so impulsive and not doing my homework before investing my money.

The squiggly lines are due to having a small "exit pupil" at high magnifications. When the aperture in mm of a scope drops to about 85% of the magnification figure, floaters become more noticeable.

This is interesting I was first testing this EP during the day just looking at far away trees etc I take it my eyes where at the most undilated they can be. At the time I just thought since it was so bright during the day that I wouldn't have any problems.

I should really test this EP again under optimal conditions (on a night with good seeing and with my eyes accustomed to the darkness etc). Its just been really poor weather recently so I've not had the chance (yet ).

[great_bear]

This is interesting I was first testing this EP during the day just looking at far away trees etc I take it my eyes where at the most undilated they can be.

The exit pupil figure is unrelated to the pupil of your eye. At magnifications figures greater than 50% of aperture size in mm, the beam of light - whose width is referred to as the "exit pupil" - is narrower than your even the most restricted human iris, and it's when it gets narrower than about 0.85mm that the floaters really show.