First Telescope - Accessories?

[KrayzieFox]

Hello all,

I just recently joined this forum in hopes of getting some expert advice on an upcoming telescope purchase, so if you guys don't mind, I would really appreciate it if you could take a few moments to help me out.

I've pretty much decided to get either an 8" or 10" Dobsonian, they seem to offer the most for your money and from what I've found Dobs are great beginner scopes. I was first leaning towards the 8" due to it being smaller, but I'm not more inclined towards the 10 as they're not that much more expensive and are barely bigger/heavier. Am I wrong to assume that the extra 2" in aperture will give me significantly better views of the night sky? I don't think I want to get anything bigger than 10" though, I couldn't really transport a 12"+ Dob very efficiently...

Also, throughout my current research, everyone always appears to suggest to us newbies to save our money and get a set of "good" eyepieces and a barlow, but what makes these components "good"? I really like the looks of this Celestron kit that comes with a 2x Barlow, Plossl eyepieces, and a variety of filters, but the price tag has me worries that they're not that great quality. Anyone have experience with this particular line of products?

http://www.telescopes.com/telescope-eyepieces/125-inch-eyepieces/eyepieceandfilterkit125inchformat.cfm

If you guys could chime in on these two products and offer your thoughts, I'd really appreciate it!

- 8" vs 10" Dob

- Celestron EPs vs others?

Thank you!

[happy-kat]

Hi

I went the path or choosing individually the eye pieces I wanted, a kit can have stuff in it you never use but you paid for it. Some people buy one eyepiece from a range they like and over time slowly get more from the same range.

Is it far from storage location to observing location, are there stairs involved?

The mirror in the 10" being bigger I would have thought would make the weight more. Some websites list the weight of the base and OTA so you could compare.

If you could get to a astro shop or meet you could get an idea of size, views and portability.

[Night Hawk]

Hi, I've not had my scope 200p long but I think it's a great scope. Not too heavy and easy to store in the garage. I find it big enough for me, however when the scope is almost verticle I do get a bit of neck strain and I'm average height. I think the golden rule is bigger the better so if the 10" is in your price range then get it. But then there's always something better that just costs a little bit more.

Regarding EP's with my limited experience and loads of research. The stock 10mm and 25mm that come with the cope can either be good or bad and on first use you really don't know any difference. My first purchase was for a Barlow 2x which I used with the 10mm and thought what a load of rubbish the barlow is. I then purchased a skywatcher 6mm uwa. The build quailty seems 100% better than the stock EP's and Jupiter was alot better with the 6mm. The barlow also seems better with 6mm than 10mm, making me realise the 10mm ep just sucks big time. Can't comment on the 25mm ep, however I do have Vixen 30mm npl on order which I can't wait to try out.

As other SGL members have said in various threads you only need a few EP's and you'll only probably ever use few . And don't forget when barlowed you've doubled your ep collection.

As with everything is down to cash, reasearch and maybe a little trial and error. But at the end of the day it's just about enjoying yourself and tinkering around trying out what suits you.

Hope this helps or even answers your question a little bit

[laudropb]

Hi there about a year ago I was making the same choices as you. In the end I went for the 8 inch Dob. I found that the extra weight of the 10 inch was too much for me. As for eyepieces, on the advice of most here I have went down the individual ep route. I have found wide field views easier on the eye and useful in locating targets. I also got a decent zoom, 8-25 mm and this is useful under some circumstances. The other common piece of advice given on the site of taking your time and going to club outings or star parties and seeing equipment in action is also very useful.

[Lowjiber]

Let's look at focal ratios for a minute...

A 10" Dob is typically around f/4.7 and a typical 8" Dob is usually around f/6.  Faster scopes (<f/5) give better results with multi-lens, multi-stage eyepieces such as the ES and Baader Hyperions.  Somewhat slower scopes are not that sensitive and a decent Plossl will serve just fine.

Now, for a peek at True Field of View (TFOV)...

Dobs do not offer a wide TFOV.  A typical Plossl eyepiece has an Apparent Field of View of 52^o and an Explore Scientific EP is available with an AFOV of 82^o.  If you compare an 11mm ES to a similar length Plossl, the ES will give you a TFOV of 0.72 deg, compared to the Plossl at 0.46 deg.

Now, take a look at light-gathering ability.  Without considering the secondary obstruction of either, the 10" Dob will gather 56% more light than the 8" Dob.

I always tell folks that an 8" Dob is a "Goldilocks Scope".  It's not too fast, nor too slow... It's "just right".

The 8" will give nice views, albeit with generally smaller fields of view and less photon-gathering ability than the 10".  The 8" will accomodate Plossl eyepieces much better than the 10".

The 10" gives more of both criteria, but really requires eyepieces that are a step-above Plossls to be satisfying.

In my case, I prefer the 10", simply because of its light gathering ability, and am willing to make the investment in better eyepieces.

You can't really "go wrong" either way.

Regarding that "kit"...

First off, if you decide on the 10"... forget that kit, as it's full of Plossls that will disappoint you.

If you decide on the 8", still forget that kit IMHO.  As others have stated, you'll end up with some EPs that you won't use and the filters are mostly a waste of money.  I suggest buying Plossls that are of a higher quality and selecting the few filters that you'll want later.

Getting off soapbox now.

Clear, Dark Skies

[KrayzieFox]

Ok, thank you all for the feedback.. I'll forget about that kit. 

So then how do I go about evaluating these optics anyway? I'm all for spending a bit more to get a better product, but I'm kind of at a loss when it comes to figuring out what's high vs low quality. I'd like to be able to make a semi-educated purchase to avoid trial and error evaluations, I'd love to get into astronomy but I'm a college student on a limited budget so I'm trying to make every purchase count. 

Thank you all!

[Qualia]

So then how do I go about evaluating these optics anyway? I'm all for spending a bit more to get a better product, but I'm kind of at a loss when it comes to figuring out what's high vs low quality. I'd like to be able to make a semi-educated purchase to avoid trial and error evaluations, I'd love to get into astronomy but I'm a college student on a limited budget so I'm trying to make every purchase count. 

I think the only way one could realistically evaluate optics is to have a fair bit of experience under one's belt, appreciate the different kinds of eyepieces on the market and to test and compare them on different objects, perhaps with different scopes and preferably with faster scopes which are more demanding. Obviously, this is something most of us cannot do but thankfully we've got some excellent threads and dedicated eyepiece reviewers in the eyepiece section which tries to clear the field.

There's certainly no need to go spedning loads of money to get decent eyepieces but extracting budget from the equation and purely looking at quality glass, some of the the most popular options in no particular order appear to be:

Tele Vue

Pentax

Explore Scientific ES68, 80 and 100

Meade 5000 UWA

William Optics UWAN's

Skywatcher Nirvanas

Orthoscopic like Baader's Genuine

X-Cels LXs

BSTs

If field of view and eye-relief weren't a concern, or if budget was a little tight, then buying into a set of Baader Genuine Orthos and Tele Vue Plossls would be a good move. These eyepiece should not be judged in terms eye relief or field of view, for after all, that limiting factor is something inherent in the physics of them, but more of the promise they give of great light transmission and sharpness across the field of view.

They're certainly not everyone's 'cup of tea' and certainly not for all occassions, but for planetary, lunar, solar viewing (with correct filters in place!) and 'getting in there' on some DSOs, I feel observers will find the view rivaled by few premium eyepieces. TV Plossls and Baader Genuine eyepieces will show as good a quality image as more expensive glass, but obviously with less field of view and less eye-relief.

When deciding upon your next eyepiece, it is always conducive to work along the lines of required magnification, exit pupil, true field of view, eye relief, length and weight. A proper choice will depend on your specific circumstances and desires. Needless to say, you cannot expect to know what you want until you have had some practice with your scope.

With that said, if I had an 8" or 10" for general DSO hunting and observing, I'd probably be looking at around 90x for my medium-low and around 120x for my medium high.

Critically speaking, I have a couple of Delos and find they produce orthic quality images in the superlative. I mean that quite seriously. The comfort is excellent. Eye relief is extremely generous. Contrast, tone, sharpness and light through put is amazing. Their ergonomics and finish is simply gorgeous. In my own case, I figured that for general DSO work I only needed two eyepieces. Moreover, I realised that these eyepieces would be with me for a number of years, if not for life, so I slowly saved up for them.

For lower power work for 1.25" eyepieces, I find the Tele Vue Panoptics are really nice eyepieces. They're small and light so you can carry them about with ease and you won't suffer from any kind of balancing issues. The 24mm will show as much sky as a 1.25" will show and they're as sharp as tack right across the field of view even in fast scopes like my f5. However, I find the 24mm does pincushion a little on large objects like the Moon or the Sun - a mute issue when it's only used for checking out star fields or finding faint objects.

I can't comment on any of the other eyepieces mentioned above but I'm almost certain they will also get top marks from those who use them.

But my heart says, don't go buying a load of eyepieces but instead, save for two really cracking, premium, quality glass eyepieces and a decent low power eyepiece and Barlow that will last you many, many years. Keep an eye on the secondhand market and you will save yourself a lot of money.

For a good number of reasons, I'd personally go for Tele Vue and make them lifers and if that means saving a little longer, so be it