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Lunar

What eyepiece focal length?

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I've recently purchased a 6" f5 newtonian (focal length is 750 mm), and wish to get a couple more eyepieces and a barlow for it. I have 20mm (37.5X) and 10 mm (75X) plosles which came with the scope. They seem ok for deep sky, but not likely to be of much use for decent views of mars, saturn, and jupiter which I hope to be able to see later this year.

What other magnifications would you guys recomend for a minimalist such as myself, for all round planetary and deep sky work?

Cheers.

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Some questions:

Do you normally where glasses to observe?

Is your scope fitted with a 2" focuser?

Are you happy with the two eyepieces supplied?

How much were you thinking of spending?

That should give us a good idea of what to recommend :D

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Thanks for the quick response Steve, to answer your questions:

1. I don't wear glasses,

2. I do have a 2" focusor

3. I havn't had much use out of my current eyepieces yet because its been pretty much cloudy every since I got the scope, but ok for now untill I get more use out of them and upgrade the one I use the most in the future.

4. I suppose Im willing to spend about £80 - £100. If I can get the same quality for less then I'm very happy indeed. I'd much prefer to have a couple of good eyepieces that I will use a lot than loads that will just get in the way.

Thanks

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My reflector has the same specifications as yours. I would recommend that your shortest ep should be a 5mm (150x), and you should have a good 2x Barlow for nights of excellent, exceptional seeing. I have a 32mm Plossl for searching and for observing large DSOs.

The eps I use most are my 32, and an 8. I put in the 5, and sometimes the 8, Barlowed, for planets. I rarely get nights which reward higher magnifications than that. Also, at 300, you will find yourself squinting a bit, and chasing objects that flee the FOV quickly while you are trying to focus on them

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I've recently purchased a 6" f5 newtonian (focal length is 750 mm), and wish to get a couple more eyepieces and a barlow for it. I have 20mm (37.5X) and 10 mm (75X) plosles which came with the scope. They seem ok for deep sky, but not likely to be of much use for decent views of mars, saturn, and jupiter which I hope to be able to see later this year.

What other magnifications would you guys recomend for a minimalist such as myself, for all round planetary and deep sky work?

Cheers.

Can I ask where the scope was bought? Was it from a reputable source. I am thinking at f5 the figure on the mirror will have to be good to stand magnifications suitable for planetary observation. The amaller the f ratio, the more difficult it is to parabolize a mirror. I have seen mirrors that have been left spherical at f5, and they just crumble under higher mags.

Barkis. :D

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Thanks Warthog, that was much appreciated. You've definitely given me something to think about.

By the way, Barkis, its orionoptics uk and supposed to be 1/6 wave with highlux coatings, and set up on a vixen GPE equatorial mount (all got second-hand at a bargin price :D), so I expect pretty ok views once collimated appropriately and motorised.

I don't really want super-super-high magnifications anyway but high enough to get nice closeups of the moon and nicely framed views of jupiter and saturn.

cheers.

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I agree with the Warthog here. I own (for sale now) a 6 inch F/5. Best for Jupiter was a 5 mm ultrascopic or a 10 mm barlowed.

Highest magnification was 180 till 200x(7.5 ultrascopic barlowed) best used on the moon or Saturn on good nights

A 32 mm is good for DSO or if you can spare the money a 24 mm pan wich has thesame FOV as a 32 mm plossl eyepiece but with better contrast due to the bigger magnification.

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Given a clean slate (it is rare that telescopes are supplied with 'keeper' eyepieces) I would opt for a 'family' of eyepieces so that they are parfocal (little or no need to refocus when changing eyepieces).

I am a big fan of Meade's Series 5000 Super Plossl eyepieces: 60 degree FOV, 5-6 element designs using modern glass with individually tuned lens coatings and blackened edges.

A set is available consisting of: 5.5, 14, 20 and a 2" 32mm (wonderful eyepiece!).

http://www.firstlightoptics.com/proddetail.php?prod=ms5000spset

Barlowed, they become 2.75 (for exceptional seeing conditions!) 7, 10 and 16mm - a total of eight magnifications, none of which overlap.

The attached image shows the FOV covered (without barlow) when used with your scope.

Hope that helps :D

(click to enlarge)

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Thanks Warthog, that was much appreciated. You've definitely given me something to think about.

By the way, Barkis, its orionoptics uk and supposed to be 1/6 wave with highlux coatings, and set up on a vixen GPE equatorial mount (all got second-hand at a bargin price :D), so I expect pretty ok views once collimated appropriately and motorised.

I don't really want super-super-high magnifications anyway but high enough to get nice closeups of the moon and nicely framed views of jupiter and saturn.

cheers.

I did not mean to cause any offence, I could have worded my remarks better. I see now you have an excellent instrument there.

Barkis.

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I did not mean to cause any offence, I could have worded my remarks better. I see now you have an excellent instrument there.

Barkis.

Barkis,

I did not mean to come across in that way, I understood your meaning and no offence was ever taken.

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