Lenses & Barlows

[Saturn1]

Good afternoon again all,

I am in the process of purchasing a 2nd hand scope, but it doesn't come with any lenses.

Could you be so kind as to give me some advice/recommendations on which would be the best for my money.

I have approx £100 to spend which I know isn't a great deal, but for a first timer it's enough for starters (I'll save the big bucks for when I have a bit more expeirience).

Thanks for your help.

Tony

[arad85]

I'm assuming this is for a 10" f/4.8 newt which is capable of accepting 2" eyepieces

Personally, I would go with lenses and not bother with the barlow at this point. As I mentioned in PM, I'd go for 3-4 lenses, covering wide angle low power, wide angle (if possible) medium power and high power... My suggestions were: 30mm WA revelation, 20mm WA revelation (both from Telescope House) and one or two plossls (perhaps the Skywatcher ones or a better single one around 6-8mm). Yes, they will be distorted around the edges but you need to get a feel for where you want to go....

(just posted to let others see what I suggested - they can then freely rip me to shreds if needs be )

[Saturn1]

See, I said I was a newbie, how much more proof do you need, lol:cheesy:

[The Warthog]

You don't give any details of the scope you are buying, but I would refer you to this article written for people in just your situation. It gives advice on how to pick eyepieces without breaking the bank.

[Harmartolos]

Hi Saturn1,

Still a newbie myself so this may not be the best advice, but I can certainly sympathise having been through pretty much the same thing myself and recently.

1/ There is a great 'sticky' by The Warthog at the top of this section, you could do a lot worse than reading it as your top priority.

2/ A lot really does depend on the scope; but most seem to come with 2 eyepieces; one medium-low (say 25mm), one medium high (say 10mm) and a 2x Barlow. There is however little point getting a 10mm eyepiece with a 2x Barlow if a 5mm eyepiece would be beyond your scope's effective magnification (about twice the primary lens/mirror in mm), far better getting say a 12.5 mm and adjust the medium-low eyepiece accordingly (25mm becomes 12.5mm with a 2x barlow).

3/ FLO (see the link at the of the page) are doing a good deal on Skywatcher eyepieces at the moment. for £100, and if you have done the maths from The Warthog's primer, you could get 3 good plossls and a decent enough Barlow. Also, the guy who answers the phone at FLO is a whizz on this sort of thing (he seems to do be able to do the maths in his head after asking just a few questions about your scope); anyway he sorted me out a treat and the stuff was delivered the next day (I am still waiting on stuff I order from 'Scopes n Skys/Pulsar' weeks ago!).

Hope this helps, but I am sure a lot more experienced people will be able to give you a lot better advice.

[Harmartolos]

LOL. I took so long to write my reply that you already have a post from The Warthog.

I therefore change mine to whatever he says.

[Saturn1]

I should have stated, the scope is a 10" f/4.8 newt which is capable of accepting 2" & 1 1/4" eyepieces. If you have any suggestions for the price range I have said, please feel free to do so.

Tony

[The Warthog]

In that price range you can get Plossls, which are perfectly good eps. I would suggest you read some reviews of the eps you intend to buy in order to get an idea of their performance in a fast scope.

I would suggest lengths of 6, 10, 16, and 24mm following my own advice. If you are very limited in your budget, I would suggest buying the 10 and the 24 now, and saving up another month or so for the other two. Another option would be 6, 2x Barlow, 18 and 24 or 25, in which case you should get the 24 and the Barlow first.

[Saturn1]

Thanks WH, budget is a little limited at the moment, £100 approx.

I would like to get something just to get me started, so I think I'll look towards the 2x Barlow, & maybe the 18 & 25, do you think that's a good start??

Happy viewing

Tony

[The Warthog]

I think that's a great start. Remember to ask and check reviews for the performance of your prospective eps in a fast scope, as some less well-made eps tend to get fuzzy at the edges in a fast scope. You should get magnificent views with that scope!

[arad85]

I have to say that I've been less than impressed with cheap barlows. I'd leave the barlow and get another lens instead - say around 7-8mm. Mine only comes out when I want to get a 5.5mm eyepiece (11 being my shortest eyepiece) or using a webcam. And that's using a decent (£80 Celestron Ultima) barlow.

[Saturn1]

Arad85,

Point taken, with tha scope being capable of the 2" & 1 1/4", which would be the best size to get. I'm assuming that purely on cost, the 1 1/4" would be better for cost.

[arad85]

Best size what Saturn1

[Saturn1]

Sorry, I did it again, lol

The scope takes lenses of the 2" & 1 1/4" fitting if that's the best way to descibe it.

Which size of lens i.e 2" or 1 1/4"?

I'll get the hang of this one day, lol

[arad85]

No probs Saturn1

2" cost more (more glass) and you only benefit from them with wider angle/longer lens length. Which lenses are you looking at?

[The Warthog]

Teh size of the ep begins to restrict Plossls at about 24mm, and wider angle eps at lower numbers. Manufacturers seem to keep to the 1¼" size until the FOV requires that they go to 2".