First Scope, Yet More Questions.

[Red268]

Hi all,

A few months back, I was looking at buying my first scope, but situations changed and I wasn't able to.  However, now I am looking again, but have a few more questions to ask of you fine people.

Firstly, we'll start with the scope:

I've been looking at the Skywatcher 200P Dob or the 250PX Dob, and my main question here is - is the 250 worth the extra money?  If it depends on what I want to look at, the answer is everything!!  The moon, the sun, planets, stars, nebulae, galaxies .... the whole lot!!  I'm happy to spend up to around £600 total, with eyepieces etc, but don't want to throw money away if it's not going to be much better.  I've looked and looked, but can't seem to find any decent comparisons photos/descriptions - they must be out there, but I can't find them!  I'd really like to seem some decent comparison photos/descriptions of the differences.

Secondly, eyepieces:

Given my budget of around £600 all in, I'd like some advice on eyepieces.  I'd done a lot of reading of other posts on this forum, looked in magazines, read reviews all over the place .... but now I'm just more confused than when I started!!  It seems the general consensus is to have a set with something like a 6mm, 10mm, 17mm, 25mm, 32mm, and a 2x barlow, which is fine, but everywhere I read suggests different makes etc.

Also, I wear glasses, and am wondering if this is going to be a problem at all?  Would it be worth getting some contacts just to make life easier?

Fitting in with eyepieces - filters.  Again, everywhere I look seems to suggest different filters.  I will certainly want a lunar filter and a solar filter (I know I won't be able to resist looking at the sun while I'm waiting for night to come around!) but people talk about planetary filters, and I'm not sure I understand the point of them?  Sorry if that seems a little dim (No pun intended!) but I thought the more light the better?  (Other than with the sun, and the moon as they're so bright!)

Thirdly, SIZE and portability:

I've been researching for many months now, and I constantly read about the 200P being a good size, easily portable etc, and how anything over an 8 or 10 inch scope is too much trouble to be used often.  But, out came the measuring tape today, and frankly, 8, 10, even 12 inches doesn't look very big!  I understand that I'm not going to be buying a Hubble sized scope, but it just looks .... tiny!  It must be the kid at Christmas thing, I just want the biggest shiniest thing I can get my hands on - also, I'm still finding it difficult to imagine how something so small could let me see things so far away.  I haven't even got my first scope yet, and I'm already getting apature fever, how is that possible?!  Started out looking at the 130P, then the 200P, now the 250PX, and I'm already wondering if the 16" ones might be a better idea!  (Only thing stopping me there is the cost!)

On the portability front, I don't understand the problem - it's not very big, the 250PX for example is just over a meter long, and obviously just over 10 inches wide, and only 15Kg (Tube only - base is 16Kg).  What is it I've missed?  If it's just the weight, that's understandable.  Weight isn't an issue for me (Apart from the belly) so lifting things in and out of the car is fine.  I have a decent sized hatchback, so with the seats down, I don't think there will be a problem there.
 

I know you guys answer similar questions all the time, and I assure you I've used the search function and Google!  Just it's more reassuring to have a personalised response, as everyones situations are slightly different.  Also, apologies if I've said anything daft!  I am certainly very much a newbie still!  I think I've read too much and confused myself more than helped myself!

Thanks all,

Red

[Schorhr]

With a car, everything is relative ;-)

But check out http://translate.googleusercontent.com/translate_c?depth=1&nv=1&rurl=translate.google.com&sl=de&tl=en&u=http://taunus-astronomie.blogspot.de/2007/03/teleskope-im-groenvergleich.html%3Fm%3D1&usg=ALkJrhg_dz4uFwVftSyzOgb6SE-Hq8eHeg

(translated)

10" is a nice regarding size, weight and price. Compared to 8" it will Show a tad more, especially for deep sky objects it will make a difference... But if you compare the view through both telescopes under mediocre sky conditions directly, it will Not allways be an obvious difference.

Regarding eyepieces: Don't Get carried away! :-)

A f/4.7 aperture Ratio is a bit critical though regarding the sharpness on the outer field on inexpensive eyepieces. So if you can choose a 10" with f/5 or slower.

For the beginning an eyepiece for higher and one for Löw magnification, and one or two is enough. Or just two and a barlow.

That could be a 32mm tswa, 10-12mm eyepiece and a 2x barlow or better another HR Planetary.. IF you can live with the mediocre performance on f/5 of the erfle.

Else check out the Explore scientific, I'd buy those if I would buy my telescope now, perform well at f/5 I hear and are not too expensive, but two or three will cost as much as a 8"...

[happy-kat]

My partner and I wear glasses for different reasons both of us take them off to use the scope as with using one eye we adjust the focuser to suit us.

So wait and see whether bother to get contacts.

[Schorhr]

My fiancee likes to keep her's on due to astigmatism, but with smaller exit pupil this is not so much of an issue anymore.

The hr/tmp are probably the best budget eyepieces regarding sharpness and eye relief, though there are better choices if there's more money to spend...

[Charic]

Red268..........Hi. I purchased the Skywatcher Skyliner200P last week(arrived Tuesday) its a nice bit of kit @ £289 delivered. As for the difference between this and the 10 its only two inches! but joking aside, unless conditions are going to be perfect, Id say it might be hard to tell the difference between the two. Fact is, the 10" will gather more light than the 8" so for satisfaction, the 10" would be a better  choice if affordable.  Now lenses, that wont be easy to choose either. Full set, half set, Barlows, Extenders, the list goes on. Look through my posts and you`ll see Im having the same nightmares over choices. The two lenses supplied are OK, but again,  if affordable, there are better quality lenses out there. I`ve only been out twice in the Week, with the scope as the weather up here is  bad . I`m still needing to confirm that my collimation is ok, but Ive seen Jupiters moons and M23, but need to get a proper dark night away from the light here. I thought it was a fairly dark site here, but the more I look the worse it gets ( local light pollution- not the scope)

[impactcrater]

There's a lot of first scope discussion...the first buy is a challenge w so many good products out there. I'd spend the 600 on a commercial unit and worry about adding extras later as money and interest grow.  personally, I would not buy over 6 " as an amateur as 'shake' is more noticeable the bigger the aperture. personally, I would not be without 'goto' as once understood, the scope finds objects with quite high accuracy and it tracks the object of interest. the heavens move remarkably quickly and you will always be looking to find the object rather than just observing it...and you can go and have an evening meal and return and there it still is...wonderful....

the commercial makers have good sites with lots of information of the scope in action...

also look at the specifications and realise the limits of a bigger scope over a slightly smaller one...note the arc seconds separation your choice will discern...

ps. relative newbie myself and very satisfied w my unit...but I will not biasis you.....

impactcrater

[baggywrinkle]

I do not have experience on dobs but have seen a few and if the Mrs turns her head long enough I could well sell my 6SE and get a dob. The specs are impressive.

Is there an astronomy club nearby? or have you been into an astro shop and seen the 200 or 250 DOB?. Looking at a ruler and that extra 2" does not cover the extra tubing, mirror weight etc.

That first choice is difficult and like a car it will never be your only purchase.

[Red268]

Thanks for the replies thus far.

I think I've changed direction again! - while I was leaning towards the 250, I'm now thinking I'll get the 200, see how I get on, then if I get really in to it, I can just save for a couple of months and buy myself something much larger with GOTO.  I figure if I start with the 8", moving to a 16" will be a nice jump, and I'll have done my basic learning without GOTO, which to me sounds like the more fun way.  I'm a little worried about getting GOTO straight away, as I don't think I'd learn the skies properly - personal preference/opinion, I know everyone is different

I know enough about star locations etc to bore people with, but not enough yet in my opinion.

[Schorhr]

That's a good plan, as 8" will show much and using a telescope without goto is not as hard as some make it seam, plus it's amazing to learn finding objects.

A decent book/map and a telrad finder are a great combination and make manual finding things easy. Tracking objects with a DobsonIan is also simple. Even at 200x, and with some practice much higher magnifications... Wide angle eyepieces are so affordable, especially as the 8" has a moderate f/6 aperture ratio, that even 30€ UWA eyepieces work great.

A 16" will be an amazing step up to 8", while 10" only makes a marginal difference. Though if transport and such is no issue, a 10" will gather 50-60% more light then 8" and may make the difference between seeing a faint galaxy or not.

If tracking is an issue, a eq platform can be a nice adition, and be bought later on.

A cheap goto alternative is a end-of-life android phone for 40€ (or cheaper used) and a red transparency sheet, and Astro Tools. It's not ideal as it will affect your night vision, but with one or two layers of red sheets (anaglyph optics or stage spot light transparencies) it's not as bad as a display in "night mode" as it still emits some amount of white light.

[Avocette]

Hi Red,

Buying second-hand and therefore afflicted by what came on the market locally ('collection only') I've ended up having a bit of experience first hand of the 200p and 250px SW Dobs as well as the two other scopes in my present signature. The weather and the 'seeing' are the most critical factor in determining performance on a particular night and although I tried a side by side comparison 200p to 250px, I wasn't conscious of any great difference between them. Other differences in handling at the time (I'd fitted the 200p with a Lazy Susan bearing and setting circle by then) and perhaps the quality of my attempts at collimation made them seem pretty much the same. I concluded that the 200p at one year old and ~f6 might have had marginally better optics in combination with my Celestron Plossl and SW Super Plossl eyepieces than the ~5 or more year old 250px f4.7.

Subsequently I changed the 250px focuser from the original rack and pinion to the SW Crayford type and whilst doing so properly aligned the focuser and secondary mirrors by measuring the scope tubework and using a collimated laser collimator. Now, for the first time the view in my Cheshire collimating eyepiece was correct. In the meantime I'd also fitted a setting circle to the 250px and modified the bearing/teflon pads on the azimuth axis.

I haven't tried a side by side since then because another factor has come into play - Dew. I much prefer to use the 250px now because I can stand the tube on its bottom end on carpet as I disassemble it and reassemble it outside. The 200p has Bob's Knobs and springs in place of the original countersunk collimation screws, allen head grub screws for locking the collimation, and neoprene O rings. Unfortunately due to the minimal size of the mirror cradle and tube end metalwork, the knobs protrude beyond the tube end so when I separate the tube for carrying outside, it must be placed horizontally on furniture (e.g. bed or sofa), not something I'd want to do after observing when the tube is wet with dew, even after wiping with a towel.

My 250px is an old one, and I would be keen to find out whether a new 250px is still fitted with collimating knobs which are recessed inside the tube end casting, or have they been 'value engineered' to countersunk screw, grub screw and O rings, and would Bob's Knobs protrude like they do on the 200p?

[Red268]

Thanks again everyone.

I took the plunge just now, and the 200P, the premium cheshire collimating eyepiece (Yes, just because it is red!!) and also the variable polarizing moon filter.

Also ordered Turn Left At Orion from Amazon.

Now, I'm going to go and sit by the front door for a few days, waiting.

Red.

[Schorhr]

Congratulations! That's going to Get you started very well.

What eyepieces come with your kit?

[Red268]

10mm and 25mm.

I'll add more as time goes on, but it's a nice start.

[Schorhr]

Sure, that's a decent start and there's no need to get everything at once:-)

You could get a 16,50€ (shipped) 2x achromatic barlow for stunning views of the moon and planets, cheap solution with great effect...

...and later a few nice wide-angle eyepieces, especially a better overview eyepiece.

Have fun with your telescope, clear skies!

[Red268]

Scope has already arrived and been set up, less than 22 hours after ordering it!!  From time of order, to being in my house, it only took 18 hours!!

Just waiting on the Cheshire and the filter.

Typically, as I've read time and time again - Last night we had clear skies here, and now it's pouring with rain!!  I am now a believer in the curse!!

(P.S.  Lots of exclamation marks because I'm so excited!!)

[Schorhr]

Wow, that's quick, have fun with your telescope!