200mm(8") Dobsonian or TAL 100RS what would you keep?

[Charic]

Hello everyone.

Ive recently aquired a Celestron 127EQ for £70 which included the Philips Deep Sky Observer starter pack and the BBC Wonders of the Solar System book (Cox/Cohen).

Since my very short ownership and far too many cloudy nights, Ive seen the cratered lunar landscape on the Moon,and viewed 3 moons of Jupiter, but no real detail on Jupiter, and still struggling to actually see Andromeda Galaxy M31 in my Zenith?

Value wise, I`m ok with the setup, however, optically? Im sure i can better the situation with TeleVue or Plossl lenses, BUT IS IT WORTH THE UPGRADE?

This scope uses a corrector lense in the focus tube , which I believe is a problem for laser collimation, unless removed prior to collimation? (fiddly or what) Ive yet to construct the basic 35mm film case to create a collimation cap (to thoroughly check the scope ) although reflected image of eye appears central at present.

EQ mount is fiddly unlocking/locking to rapidly move the Telescope to a new object, which is why I can see the virtues of a Dobsonian mount, but with all that nudging instead of turning a knob for tracking accuracy, surely both methods are best.

So thats the score of my set-up, but I`m chasing my tail, with information overload, and some spare cash, and want to buy a newer system, that will work for a lifetime.

Given the list of sightings above, as a guide to my viewing habits, I`m drawn to both the Skywatcher Skyliner 200P Dob and the Orion XT8 8" Dob telescopes, but also the TAL 100RS keeps messing with my mind?

Given a budget of @ £350 what would be your choice today and why?

As per some signatures, it appears that several scopes are required these days to cover all aspects of astronomy. If you had both scopes above, and had to rid one of them, which one and why?

As for the TAL, I would later budget for an EQ mount.

Many thanks in advance.

[John]

I'd go for the 8" dobsonian every time, probably the Skywatcher as it's usually less expensive than the Orion (USA) equivalent and contains the same optics. I'd also like a TAL 100 to compliment the dob. I'd prefer both over the Celestron 127 to be honest.

Any of these scopes should show you the sights you seek in your paragraph but you need a bit of patience to see fine planetary detail and to find deep sky objects.

Better eyepieces would be a good idea but you don't need to spend Tele Vue money. Vixen NPL plossls or the BST Explorer eyepieces will show you what these scopes and the conditions are capable of.

If I had to go for just one of the scopes it would be an 8" F/6 dobsonian though.

[ronin]

Could you put a more specific location in your details. The 2 scopes are somewhat different and oddly one or the other may be preferential on where you are.

Concerning eyepieces then yes an upgrade is worth it, the supplied ones are these days sort of minimal and I suspect will put more people off of astronomy then anything. You can get Vixen plossl's at around £35 and BST at £47 (?) both of which will be a lot better.

Scope wise if the 127EQ is a Mak then it is bigger then the TAL in diameter and to some extent would produce similar results (well on paper they "look" similar).

The dobsonian will collect more light, so more things become apparent, but not everyone gets on with one. Also if you want tracking or imaging later (many do) then the dobsonian is not suitable. So not only a case of "What do I get now?"

Going to cause an arguement asking the question you have as both camps (TAL 100 vs 8" Dob) have a die hard following. :grin:

[rowan46]

If portability isn't an issue I would get the dob as it will see dso's and planets much better than the tal.

[twotter]

One or the other????

Never!!!

I need them both

[Charic]

Ronin.........Hi

If its about M31, I`m @ N57 W003 UK. Its just difficult to get the scope vertically aligned to view without being a contortionist or the adjusters or scope hitting the mount, and / or having to roll the OTA within its mount to enable the eye piece to be level? I can see M31 as a blurr through 7x50 binos( wish I still had my Stellar 20x80 but were so heavy), and manually holding the scope on a high backed chair is having a laugh, but at time of writing, Ive not centered the scope over M31 and or saturn. If M31 shows as more than a blurr and my family can see saturns rings, things will be ok. It would explain the costs at least.

[nightfisher]

I would buy the 200p dob, keep the 127 and get a couple of BST eyepieces, then you will be covering all events, the dob will surprise you on lunar and planets and is quick to set up, maybe get the 127 to an astro meet up/club and get some one to check it out for you

[foundaplanet]

4" Achro's mess with a lot of peoples minds and a nice frac is a grand thing to own and they are a joy to use but the truth is even a 6" dob will blow the 4" achro out of the way every time.

I agree with what Nightfisher is suggesting that you get what you already have looked at. A visit to an astro club would be a good place to go as you will also get the chance to look through other peoples scopes. It is possible that you may even find that an 8" or even a 10" is not what you was expecting so it is always best to try before you buy. You do live in a grand place though for astro so you are not going to be going far if anywhere for a dark location. You should be able to get some very good views with what you already have if you use it at a dark site.

[dweller25]

The Tal 100 is a nice scope but the 200P will outperform it on deep sky and the planets and have zero chromatic aberration.

[NGC 1502]

You have some good advice already, so I won't try to repeat that.

However, I'd like to comment on one thing you said regarding a Dobsonian "with all that nudging". A Dob with sticky movements is a pain, but a Dob with smooth movements is a joy to use !

A nice 8" Dob could well be a 'lifetime' scope.

Regards, Ed.

[cotterless45]

Dobs are known to be at their most awkward at any target nearing overhead. A refractor will get these , but you'll need a tall tripod or enjoy laying or crouching down. Best wait or plan your targets so that they're manageable.

The 200 Dob is not only a great scope and all rounder , it is very user friendly and family will enjoy the views. It'll pick out most deep sky targets . There are endless recommendations on this forum. You'll see plenty of detail on the planets as well.

"Turn left at Orion" and "The Pocket Sky Atlas " will help.

The Tal is an excellent refractor, you'll be needing a mount and ensure that all heights can reach the eyepiece and track the view.It won't show you the faint deep sky objects as well as the 200 Dob and is more a planetary/ lunar / star splitter,

Nick.

[Charic]

...from the replies so far, Looks like I could order a new lense, to see what improvements it makes on the 127EQ, especially under dark sky conditions (the lense of course could be transferred to a new scope) My local club seems to view Fridays & Saturday, so I might take a drive out this Week, if the skies are clear, with Monthly meetings once a Month, the next being a week this Friday. That could possibly allow me to view before purchase.

Your replies so far also seem to favour the Dobsonian as a wise choice. I like the black scheme of the XT8, but the Skyliner is cheaper, for about the same quality, Also not sure I want the scope posted to me (although they`ve already been posted / couriered to the retailers) There is a massive shortage of retailers in my area, so its either a long drive or have it couriered. Maybe information from the local club may help, they may have even negotiated discounts, who knows?

Thankyou

[Naemeth]

...from the replies so far, Looks like I could order a new lense, to see what improvements it makes on the 127EQ, especially under dark sky conditions (the lense of course could be transferred to a new scope) My local club seems to view Fridays & Saturday, so I might take a drive out this Week, if the skies are clear, with Monthly meetings once a Month, the next being a week this Friday. That could possibly allow me to view before purchase.

Your replies so far also seem to favour the Dobsonian as a wise choice. I like the black scheme of the XT8, but the Skyliner is cheaper, for about the same quality, Also not sure I want the scope posted to me (although they`ve already been posted / couriered to the retailers) There is a massive shortage of retailers in my area, so its either a long drive or have it couriered. Maybe information from the local club may help, they may have even negotiated discounts, who knows?

Thankyou

http://telescopeoutlet.co.uk/index.php/telescopes/sky-watcher-skyliner-200p-dobsonian-telescope.html

Save quite a bit on new . Enough left over for a couple of TV plossls

[Charic]

Naemeth.

Thanks, that was a good price, I`m still deciding, and Ive got the postage to cover (According to the couriers of this Island, I apparently live on my own little island, somewhere of the West coast, and accordingly, charge over the odds to deliver, yet it does`nt cost me £`s to send South. perhaps I only use Royal Mail?) So with the postage costs added, I`m heading up to the £279 prices that the 8" is available for at several retailers. So maybe £290 all-in would be fine for me.(One Company I recently spoke too about their 250P said they would only charge me £10 for the delivery! so might take up their offer, as its a sensible offer, buying the 8" Dob. After all, I live on UK mainland. (250P might just be too big for my storage/car and is the more expensive Dob. and I`m not sure theres much difference from 8" to 10*) although someone will correct me on that. I believe you would need to double the aperture to see a clear difference, and I cant afford a 16" . Im sure the 8" will be fine. Hopefully those clouds clear soon, take care.

[Naemeth]

Naemeth.

Thanks, that was a good price, I`m still deciding, and Ive got the postage to cover (According to the couriers of this Island, I apparently live on my own little island, somewhere of the West coast, and accordingly, charge over the odds to deliver, yet it does`nt cost me £`s to send South. perhaps I only use Royal Mail?) So with the postage costs added, I`m heading up to the £279 prices that the 8" is available for at several retailers. So maybe £290 all-in would be fine for me.(One Company I recently spoke too about their 250P said they would only charge me £10 for the delivery! so might take up their offer, as its a sensible offer, buying the 8" Dob. After all, I live on UK mainland. (250P might just be too big for my storage/car and is the more expensive Dob. and I`m not sure theres much difference from 8" to 10*) although someone will correct me on that. I believe you would need to double the aperture to see a clear difference, and I cant afford a 16" . Im sure the 8" will be fine. Hopefully those clouds clear soon, take care.

The tube of the 8" and 10" will be the same length, however the base of the 10" will probably be a bit bigger, and the tube will be wider and heavier. I'm getting a 250PX soon (couple of days), so I can take some pictures if you'd like .

Perhaps don't use Royal Mail? They are expensive for heavy parcels, couriers are a better bet.

[AlexB67]

http://telescopeoutl...-telescope.html

Save quite a bit on new . Enough left over for a couple of TV plossls

darn, quite good value

[Rob63]

Have to say I am very happy with my 200p Dob very practical for an evening’s observing and the views are really top quality given the price.

I added a telrad and that has made a big difference to finding object / star hopping.

A couple of BST explorer EP's have made a difference too as the supplied 10mm is not very good (although the 25mm seems ok).

It's not too big to move around the garden although not so easy to carry with you if you are heading out to a dark sky site.

[TwoPi]

Likewise, I would definitely recommend the 200P (but then I would say that ).

In terms of getting it posted to you (aside from not being ripped off), I wouldn't worry, it comes in sturdy packaging and from my experience you'll need to check the bolts are all correctly tightened and then collimate anyway regardless of whether you pick it up from a shop or get it posted.

Had someone told me that before I bought mine, I would have been a bit nervous of what to expect but with a simple Cheshire collimator there's nothing to worry about - it's dead straight forward and there are a number of posts on SGL (plus Astro-Baby's website) that spell out what you need to do.

Enjoy, whatever you decide to go for!

[Charic]

Naemeth.

....... I believe you would need to double the aperture to see a clear difference, .....

Oh dear! , just realised what I said? My 127 EQ is 5", so maybe I should get the Skyliner 10" Dob, using that idea.

My local club has`nt met yet due to the weather (so that I may be able to see / try as sugested) but that didnt stop me from looking in at their site? (lol. got a longway down a dark track in a forest only to find a locked gate, on the way out? my reversing skills are good, but I wish I had reversing lights on both sides of the car? ) I`d hope that the Skyliner eyepieces are better than the 127EQ`s, or maybe both scopes benefit from better eye pieces. If I can see some "rings" and "M23" using the 127EQ, then maybe no need to upgrade (just now?) Too many decisions, but the replies here are informative, many thanks.

[Charic]

More questions?

If using the same eyepiece on either the powerseeker 127EQ or Skyliner 8" Dobsonian, is it true that you will get a sharper/brighter image at the focal point, due to the larger aperture difference between the scopes and the fact that the Skyliner uses a parobilic mirror, against the spherical mirror ( parabolic being the better of the two optical systems ) Has anyone had the pleasure to try this test, and is the difference only minor, or chalk and cheese?

Ive still not decided on a new lense yet(brand/pricing) but any info from those in the know will be helpfull.

Not visited local club yet, maybe this friday, their monthly meet.

[John]

The 8" dob gathers around 160% more light than a 127mm scope does. Thats a lot more potential performance whichever way you look at it

You don't need to double the aperture to see the difference - the step from 5" to 8" will be significant.

[AndyWB]

... and the fact that the Skyliner uses a parobilic mirror, against the spherical mirror ( parabolic being the better of the two optical systems ) Has anyone had the pleasure to try this test, and is the difference only minor, or chalk and cheese?

If I remember rightly, the spherical mirror of a Maksutov-Cassegrain is not a problem - the other optics in the system adjust for this (specifically, the meniscus lens, a.k.a. the corrector plate). A parabolic mirror on a Newtonian reflector should outperform a spherical mirror in a Newtonian reflector, but not necessarily a Mak.

I think. From what I've read, anyway.

[Naemeth]

If I remember rightly, the spherical mirror of a Maksutov-Cassegrain is not a problem - the other optics in the system adjust for this (specifically, the meniscus lens, a.k.a. the corrector plate). A parabolic mirror on a Newtonian reflector should outperform a spherical mirror in a Newtonian reflector, but not necessarily a Mak.

I think. From what I've read, anyway.

That was my understanding too, although if you had a really slow Newtonian (F/10 to F/15), it may not make any noticeable difference whether you have a parabolic or spherical primary mirror.

[Charic]

Thankyou for the updates, a big learning curve.

Well I managed to get a clear sky last night and picked out M23 but not really impressed with the result using the supplied Celestron 22mm erecting eyepiece, and the 4mm, what a waste! ( I took that apart last night to clean and to see if it had a lens? ) I hope it `s the Ramsden Optical layout ( convex facing each other, flat sides to eye and scope! - it looks ok in the daylight) But I can clearly see I need better eyepieces. Even thought it was my own eyes playing up, but thats corrected by just focusing the eyepiece.

Pleiades comes through clear, although I wish It was as wide a view, as my Bresser Hunter 7x50s ( still missing my 20x80 hellios till I get a better scope)

I`m confident from the advise allready given that the 200P will be a better option for me, and I will probably even upgrade the supplied lenses to Plossl`s in the future, but a collimator first.

Unfortunately I`ll have to buy mail order, and most are charging upto £43 for courier delivery, although one company I have spoken to will deliver a scope for £289 total. which I`m seriously considering just now.

Still not met any locals yet (astronomers)

take care.

[Charic]

Woo-Hoo! The fire in my pocket is out? Ive just purchased the Sky-Watcher Skyliner 200P Dob. Now awaiting delivery......................................is it here Yet?

Now to review the tweaks and enhancements for this scope. Not sure of the quality of the lenses supplied, but no doubt they can be bettered at a price. Will probably buy the collimator first.