any advice please !

cwg666

I have a Celestron (Astromaster 130EQ M-D Reflector
Aperture 130mm (5.12 in)
Focal length 650mm (25.59 in)
Focal ratio 5
Can anybody advise me of the "perfect" eyepiece/Barlow lens combination to achieve this scopes full magnification potential. I currently have 20mm and a 10mm eyepieces (supplied with scope) that are disappointing.
(Theoretical Max Magnification = 2x aperture in mm's or in my case 260mm) if this is the case how "or" what combination of bits & pieces would i require to achieve even close to 200+ magnification. The only thread I've found shows that with my 20mm lens + 3x barlow i can expect a mag of 97.5x,,,, but the 10mm lens and a 2x barlow = 130x would be unusable? can this be improved upon with present eyepieces or additional eyepieces whilst retaining image quality i.e. to get up close to Saturn. any advise would be greatly appreciated as am longing to get out spotting something other than the moon..beautiful as it is... many thanks in advance ...cwg666 we all start somewhere

dmcdona

Try this:

http://www.scopesim.com/

It'll allow you to put in your basic data for the telescope and the eyepieces. It shows you a simulated view of a few user defined targets (moon, Saturn etc). At the bottom of the page it gives you your magnification etc.

Note that you can alter the preset data to whatever you like. e.g. in the telescope drop-down list, your telescope isn't there. But you can over-ride the presets by putting in your own data.

It seems to me that you'll need to invest in at least one short focal length eyepiece - perhaps 6 or even 5mm to get really decent magnification. Alternatively, get a 2x Barlow, that'll give you a 20mm, 10mm and 5mm FL combination.

Bear in mind that at higher magnifications, your view will degrade owing to seeing and the quality of the optics in both the telescope and the eyepieces.

Of course, this isn't an isse with a nice Astro-Physics refractor and some Televue Nagler eyepieces - if only...

HTH

Dave

cwg666

just off to the Liverpool astronomical society to see what its all about & to pick some brains...will try out your link when i get a chance..sounds promising.thanks once again for your quick reply..no daubt you will here from me again ..probably pleading for help carl

Stargate

Nice Link Dave ;-)

cwg666

had a chance to try out that link this afternoon and as Stargate's subsequent post pointed out it is a very nice link. Had fun combining eye pieces and scopes & barlow...achieving some very impressive results. Then i put in the details of my "scope"....oh dear..sulk sulk etc. I did in all honesty find this site useful as a rough guide as to what a can realistically expect from a £140ish piece of kit so thank you very much once again for your time. I take it from the last line of your message that Televue eyepieces are quality...would i be right in thinking this and if so do you know if they produce Quality Barlows as well as regular eyepieces? I did warn you that i would be back hassling for advice and true to my word here I am:o many thanks in advance of your cosmic advice .carl

dmcdona

Carl - in all seriousness now, the Televues are excellent eyepieces and yes, they also make Barlows - though Televue market them as PowerMates.

I've used both Televue eyepieces and powermates and they really are top quality. Of course, along with that comes a top price

Given the scope you have, I'd recommend you hunt down some of the cheaper, but very good quality Barlows out there. However, I've not done any visual observing for ages and my knowledge of the current crop of manufacturers is very limited.

I'd feel comfortable to directing you to the IFAS site (irishastronomy.org) where the folks there can give you far better advice than I.

By the way, feel free to hassle me as long as you like - I was once in your shoes and without the support of the local community, I'd've gotten nowhere. Some say I *still* haven't

Dave

cwg666

thanks Dave. will check out prices of televue and see if there's anything within my price range as would sooner have 1 or 2 decent optics than more of the kit that came with scope. Though will probably have a choking fit when i find out what they're knockin Televue bits out for... and end up buying a bucket load of tasco bits and a tube of superglue
Will also check out your recommended IFAS direction ..So top marks once again for your most generous assistance.

P.S. are YOU saying my scope is a dud and not worth buying good eyes for :D:D:D

HA HA only joking mate ...carl

dmcdona

Carl - when you're looking at the Televue website, they don't give prices but they *do* give authorised dealers. If you click on the dealers' sites, you'll see the prices... Take a deep breath and remove anything within reach that's breakable...

The Ethos eyepieces, on sale, start at $525.00 :eek:

The Plossl's are very good value but even they may be out of your price range. The Powermates are very pricey, but you'll never need to buy another. Period.

A few points I'd make that apply in your situation, and to a large extent, to all astro gear:

1. Buy cheap, buy twice. With astro gear you get what you pay for. Pay as much as you can reasonably afford, especially optics (optical tube assembly, eyepieces and Barlows etc), mounts and imagers.
2. The really good quality equipment is easy to sell on and will not lose its value by very much, if any. In some cases, you can charge more than you paid.
3. For small stuff (especially Televue), consider getting it in the USA. This way you can try before you buy. Of course, you *should* declare any purchases above 115 euro (I think) when you re-enter Ireland via the red channel. If you're not going, ask around - I've certainly brought back eyepieces for colleagues.
4. Bear in mind that if you go ahead with a purchase such as a Televue PowerMate and a couple of Plossl's, your current telescope may not do them justice. However, like any other amateur astronomer, you *will* be upgrading in the future so at that point, you'll buy something that will really match them well.
5. Keep an eye on the second hand market. The expensive stuff comes up once in a while (especially these days) and sometimes at rockbottom prices. If its quality equipment, you'll have no fear of wasting your money.

Definately have a lash into the IFAS boards
Good luck!
Dave

cwg666

Dave- at that sort of price $525.00 it may work out cheaper in the long run to save up for a trip on one of those soviet space tourist rockets! laughed my head off at your advice to remove "all breakables" from immediate vicinity..ha ha .. forgot to put telescope out of the room though and It now resembles a banana. . . still its pretty handy for checking that my shoelaces are tied or if anyone is creepin up behind me !

Will start trawling around ebay/astro mags to see if anything a millionth of that price appears.. but as you rightly pointed out..any good kit will stand the test of time so It looks like I will have rip the floorboards up or get my hand down the back of the couch looking for some misplaced dosh.
Regarding the USA, I do have family over there but am unable to ask them to purchase anything for me just now as they are dealing with a bereavement but is an option for the future once things cool down and I am the proud owner of a sack of loose change. . . carl

Oh and why no observing for ages?

dmcdona

Carl - a second hand TV eyepiece and PoweMate for sale - reasonable prices

http://www.irishastronomy.org/cms/forum func=view&catid=17&id=77762#77870

The weather has been pretty uncooperative lately but we're rapidly coming to the end of the season anyhow

Good luck!

Dave