Advice on eyepieces

[programmer]

I've read a LOT of advice on IIS about choosing a telescope (and mounts) but not a lot-correct me if I'm wrong-about eyepieces and the like. What is a good, or reasonable, set of starter gear? The Bintel dobs I'm looking into have a Crayford 10:1 focuser on the 10"+ models (same with the Meade LB's). Also correct-image right angle finder scope, 15mm & 9mm Plossl eyepieces, moon filter.. Is this a good starting set? Anything you would suggest getting when I pick up the scope, or is this enough for a memorable 'first light' with my new toy (when I get it ). I'm sure I'll have my work cut out just managing to point the thing at the moon

On a side note, is the fact that the 10" dobs come with a Crayford 10:1 focuser reason enough for me to upsize from 8"? Or is the 10:1 more necessary with the more powerful scope?

[erick (Eric)]

Bit quiet here today, programmer. OK, I'll have a shot:-

If you can afford the bit extra for the 10" and you can carry it around - in and out of home and transport it in your car - go for the 10" scope. You won't be sorry.

10:1 Crayford? Great if you get one standard. That adds to the argument to go for the 10". But any special reason why you would have a 10:1 on a 10" scope over an 8" scope - No, there is no reason - it adds the same benefit to each. I haven't used a 10:1 - I went for the electric motor control of a standard Crayford focusser instead.

Eyepieces - let's see - there are 3,270 members of IIS, so there are probably about 2,000 different opinions on eyepieces!!

Now Bintel bundle the following:- 26mm (2") Fully Multi Coated Eyepiece (Kellner design I believe), 15mm and 9mm Plossl Eyepieces. I started with these and, for a beginner, they will certainly get you well under way and seeing plenty. Find your way around the sky with these for a few months - until you can get to a star party or together with someone else and learn about other eyepieces and look through some in your own scope. This will include looking at a few different barlow lenses to see what benefit they bring.

You do need a collimating tool. From Bintel, look at the Orion Cheshire tool or the laser tool. I have both and have great success with the laser, after I'd done bit of tweaking - checking the laser alignment itself, adding a wrapping of "contact" to make the laser sit very snuggly in the focusser adapter. A barlow comes in handy, combined with the laser tool, to get even more accurate collimation of your scope.

Has anyone told you about all the accessories you will need! Planisphere, maps, red light torch, some form of seat, magazine subscriptions.... Don't give up your $-earning day job just yet!

[janoskiss (Steve H)]

If you've got a bit of extra cash, take advantage of the sale and buy up to 3 TeleVue plossls (ask in the shop which is best suited to the scope you're buying) and a TV 2x barlow - TV gear is very keenly priced atm - you are getting new for what used to be 2nd hand prices same time last year. Otherwise what you are getting with the scope is plenty to keep you busy for a while. I'd also strongly recommend a Telrad for 10" or larger scope or a Rigel quickfinder for 8". Focuser is no reason to upsize. Get a 10:1 with whichever scope you buy. It's worth it. The 8" has a lot more mobility (ie can be carried around easily in one piece), that's the big plus with that scope.

Don't forget to ask lots of questions in the shop before purchasing. Try talk to Roger if you can.

[Stephen65]

Its hard to give eyepiece advice without knowing what your budget is, the sky is literally the limit when it comes to how much you can spend on EPs.

[Tannehill]

the 10:1 focuser has finer motion control over the stock focuser, which is more helpful for the "faster" (i.e., short f-ratio) 10" (an f5 I think) compared to the 8" (f6 I think). The shorter f-ratio scopes have a steeper light cone as the image converges at the focuser, and as such the sweet spot of focus is smaller. Thus, a finer motion controlled focuser will allow you to find the sweet spot of focus more easily. It's nicer with any f-ratio scope, just incrementally more useful for the faster f5 than for the f6.

GSO (Bintel) just changed their stock gear to include that 10:1 with the faster (larger) scopes. My 12" came with the regular focuser just last year; it's not a big issue w/r to enjoying the scope. More importantly, if you can afford the larger aperture and can transport/set-up/use the larger scope without difficulty, always go for the larger aperture. 10" is not "too big" for a starter scope provided you can handle it physically and economically.

I'd say the GSO EPs are good value and very successful for a first set. Having at least two (one low power and one high power) is probably best, three is better for a good spread across the mag factors. Odds are as you progress you'll gravitate toward the more costly premium products, one-by-one.

scott

[ngcles]

Hi Programmer,

The 10" provides a 50% increase in light gasp over the 8", but it is heavier, a bit dearer and a bit more cumbersome to move around.

With the 10", the view of the planets you will get will be a bit more detailed in really good seeing and somewhat brighter. The really big improvement will be in observing deep sky stuff because you can see 50% fainter and as a rule of thumb you will see about 50% more objects, and more detail.

If the budget and your back are up to it, and if it fits in your car (assuming you want to take it elsewhere) I think the 10" is the way to go. The focuser you speak of is a very nice one.

As to eyepieces, the two you refer (15mm & 9mm) to are a good start and should serve you well for a time. You will need, pretty much immediately, a long focal length low-power eyepiece (somewhere between 25 and 32mm fl) -- something that provides about a 1 degree field of view for the large clusters, nebulae etc.

As others have advised above, before you star splashing out a lot of money on eyepiece upgrades, wait for a while till you have had a chance to look through some other eyepieces at star-parties and the like, and maybe even had a chance to try them in your 'scope before you consider upgrading. Premium eyepieces will provide a wider, better corrected and sharper view but they come at a premium price too.

Choosing eyepieces (particularly the high-end stuff) is a pretty personal thing and as someone else noted -- lots of different opinions. If you ask say 10 experienced observers, expect at least 3 if not 10 different answers.

On the other hand, there is a special on at the moment on Televue that you might consider. There are lots of other manufacturers that make top-notch gear too.

Whichever way you go, good luck with your first foray into observing with a telescope. Remember, using a telescope is a bit like learning to play a musical instrument. No one expects to pick up an instrument and play it like a pro on night one. Learning to find things in the sky, point the 'scope at it and see all the cool stuff out there is a skill. It can occasionally provide some frustrations and lots of challenges but practice and experience pays off!

It is also a really good idea to join an astronomy club -- help on tap for practically anything telescope related!

Best,

Les Dalrymple
Contributing Editor
AS&T

[programmer]

Holy cow, I should've checked sooner for responses
Here I go..

Originally Posted by ngcles

Hi Programmer,

The 10" provides a 50% increase in light gasp over the 8", but it is heavier, a bit dearer and a bit more cumbersome to move around. ]

More great advice, thanks.. another nod to the 10" too . Might add the 25-32mm EP to the list (TV?) after I look at prices and budget. Sounds like I will have a reasonable start set though.

Whichever way you go, good luck with your first foray into observing with a telescope.

Thanks again.. will be be looking at the Mornington group one of these nights, I'm sure they are a friendly bunch!

Originally Posted by Stephen65

Its hard to give eyepiece advice without knowing what your budget is, the sky is literally the limit when it comes to how much you can spend on EPs.

Well if I go the 8" I can afford maybe 1 or 2 'decent' EP's. Budget not 'huge' as you might tell from the scopes I'm considering, but also the issue is wanting to limit the 'white elephant' factor if I don't go all in for this stuff! (Edit: but I will I'm sure--think positive)

Originally Posted by janoskiss

If you've got a bit of extra cash, take advantage of the sale and buy up to 3 TeleVue plossls (ask in the shop which is best suited to the scope you're buying) and a TV 2x barlow]

Will have to see how much the 3 plossls + 1 barlow would cost. I would've thought at least one barlow would be a good idea though, even in a starter set(?) Have spoken to 2 different guys there so far, didn't get names though.

Originally Posted by Tannehill

the 10:1 focuser has finer motion control over the stock focuser ...]

Thanks for the info. Yes was at Bintel today and was told about the 10:1. Just hope they get the new stock of dobs in by month's end . Another tip for the 10"... hmm

Originally Posted by erick

Bit quiet here today, programmer. OK, I'll have a shot:-]

Definitely considering the 10", but is a big bugger and I'm sure wouldn't be taken in the car in the short term.. Will get a collimating tool but it will hopefully come out of the shop well set up(?) Don't have a red light torch, set, etc.. do have a laser though! Thanks for all the tips.

A general thank you for all the thoughtful responses! More food for thought..

[wasyoungonce (Brendan)]

Programmer, this televue site on eyepieces selections may help:

http://www.televue.com/engine/page.asp?cat=2

look at the eyepiece's for small dob's:

http://www.televue.com/engine/page.asp?ID=221

2 cents worth.

[ballaratdragons (Ken)]

Programmer, my 12" GS Dob fits in my car, so a 10" will fit even better. They aren't all that heavy. You just can't carry them in 1 piece. Carry the base out, then the tube, simple as that.

May I also recommend an EP in the 25 - 32mm area. You can Galaxy hunt with them, and they are great on larger nebs (Orion, Carina, etc).

The 25-32mm EP's also give fantastic vistas of the Milky Way, large open clusters, and the Magellanic Clouds.

[programmer]

Originally Posted by ballaratdragons

Programmer, my 12" GS Dob fits in my car, so a 10" will fit even better. They aren't all that heavy. You just can't carry them in 1 piece. Carry the base out, then the tube, simple as that.]

I might have to take the family though.. doh! Wonder if they will let me do a 'trial fit' in my car before I buy

May I also recommend an EP in the 25 - 32mm area. You can Galaxy hunt with them, and they are great on larger nebs (Orion, Carina, etc).

The 25-32mm EP's also give fantastic vistas of the Milky Way, large open clusters, and the Magellanic Clouds.

Sounds like what I'm after.. I'll be researching these. Now why aren't I in bed

[ballaratdragons (Ken)]

Originally Posted by programmer

Now why aren't I in bed

Coz you is a Astromonomer

We is Nocturnal

[programmer]

Originally Posted by ballaratdragons

Coz you is a Astromonomer

We is Nocturnal

Astromonomer?? I think YOU should be in bed

[ballaratdragons (Ken)]

Originally Posted by programmer

Astromonomer?? I think YOU should be in bed

that was the joke!
You'll get used to my humour