Skywatcher 250p vs Celestron 8SE

[Dunyb]

Hey there! I'm quite close to buying my first proper telescope and right now I'm stuck deciding between the Skywatcher 250p Dobsonian Flex Tube GoTo and the Celestron Nexstar 8SE (also GoTo).

I can get both of them for a similiar price and I don't mind the size of the 250p (not planning to carry it around too much and even if, I have a big enough car to transport it with ease). One of the things I'm not quite sure about and don't really trust is the 8SE's mount and tripod, it doesn't look that sturdy to me, but I can't be too sure about that, since I never got the chance to touch it. I've had the chance to see a larger version of the 250p though (I believe it was a 350) and I admit that at first I was a little scared of the Flex Tube design, but a couple minutes later, after taking a closer look, I fell in love with it. What I want is an all-around telescope, I don't want to focus on just planets, or just deep-sky objects. When it comes to observing, I'm mainly planning to do visual, with occiasional webcamming, might try hooking my DSLR, but beautiful astrophotographs aren't something that I want to focus on.

I'd like to hear what you think about these scopes and which do you think would be better for me. Thanks in advance.

[FarSide]

Personally i wouldn't go for the 250 flextube, i'd go for the solid tube any day of the week. The flextube from my experience has more problems than it's worth with an explosed primary but maybe this is down more to a personal thing. Also, if you ever wanted to move the flextube from it's dobsonian mount to an EQ mount you would be able to which makes your options limited. If it were me i'd go for the solid tube 250px, this gives you options in the future and doesn't have an exposed primary to the eliments.

I can't speak for the Celestron however.

[FarSide]

wouldn't be able to* sorry. Bring back the edit button!

[Dunkster]

Sounds like you've already made your mind up...

They're quite different animals to be fair. The mirror of the 250px is over 50% larger (in area) than that of the 8SE, so I can't imagine a situation where it wouldn't prevail.

If you're young, fit and healthy, I have no doubt the 250px is the better visual scope. There's nothing to trust or not about the 8SE's mount. It's a popular scope, well tried and tested. You can get a little wobble if you're not careful, but it's adequate... 8SE can be picked up and moved with one hand.

[crazyjedi]

The SW 250 will have far more light grasp than the Celestron and is a good all rounder.

Far sides idea of getting a solid tube SW Dob rather than the truss tube might be worth considering. As suggested the ability to swap it onto an EQ mount in the future is a plus point and worth thinking about.

They're both good scopes so which ever one you choose I'm sure you'll be happy. If it was up to me, I'd go for the SW Dob for it's larger aperture

[Alkaid]

I think we're forgetting that the OP does not want to do serious photography, so why would he want to put the Dob tube onto an EQ mount?

This Dob already has a GOTO and tracking function....great for visual use and fine for quick pics and webcam. To mount the 10 solid tubed version onto an EQ mount would cost quite a lot, so why bother when the dob base sitting on the ground will be more than stable for the uses the OP wants?

Both scopes are Alt/Az gotos with tracking, but the dob has 50% more light grasp as someone has already mentioned. OP - Seeing as you don't mind the additional size of the dob - go for this.

I have also read that these SW GOTO dobs have another trick up their sleeve in the fact that you can still push them to the target area, then slew the last few degrees to the target. Also, if you are letting someone have a look through the eyepiece and they move the scope off target (why do all people who look through your scope grab it by the eyepiece!...not SGL guys / gals of course) then you can quickly slew back to the target, no fuss. Useful at star parties or when entertaining family and friends.

[SeedyF]

Things to consider with the flextube

• You need a light shroud - home made or otherwise.
  
• I think it's best on a level surface for the tracking and goto to work at their best - which for me meant building a low platform to stand it on because of my uneven patio
  
• An observing chair and a 90 degree spotter will make the whole experience much more comfortable.
  
• It's 32kg when moved in one piece. Don't underestimate it. The size/shape are more of an issue than the shear weight.
  
• But it is a dream to split in two and put on the back seat of the car
  

I've no experience with the Celestron so my advice is a bit one sided.

[estwing]

dob every time...bang for buck n all that...

[Marki]

The 8SE mount is adequate, but a little wobbly if you knock it. Not so bad on grass, and I believe that the vibration suppression pads are actually pretty useful. I like the scope - easy to use/mount/transport etc., but the 10" will beat it for views (better light grasp).

[FarSide]

I think we're forgetting that the OP does not want to do serious photography, so why would he want to put the Dob tube onto an EQ mount?

This Dob already has a GOTO and tracking function....great for visual use and fine for quick pics and webcam. To mount the 10 solid tubed version onto an EQ mount would cost quite a lot, so why bother when the dob base sitting on the ground will be more than stable for the uses the OP wants?

Both scopes are Alt/Az gotos with tracking, but the dob has 50% more light grasp as someone has already mentioned. OP - Seeing as you don't mind the additional size of the dob - go for this.

I have also read that these SW GOTO dobs have another trick up their sleeve in the fact that you can still push them to the target area, then slew the last few degrees to the target. Also, if you are letting someone have a look through the eyepiece and they move the scope off target (why do all people who look through your scope grab it by the eyepiece!...not SGL guys / gals of course) then you can quickly slew back to the target, no fuss. Useful at star parties or when entertaining family and friends.

First of all, all i was doing was giving the OP some option options. If he gets a flextube he will never be able to mount it onto a EQ should he ever wish to get seriously into AP, and by buying a 1.7k 10" Dob he's effectivly wasted his money. IF he gets a solid tube he can mount it onto an EQ mount later on - you have to keep you options open in favour of future wants and needs.

[FarSide]

My apologies: for a 250px goto it's £960 from FLO - i was thinking of the 350p for some reason. It's still alot of money to waste of he'd want to get into AP later on.

[tim22]

I bought the Synscan 250 goto Dob from FLO in June and am very happy with it. Having set up I have onl;y needed to adjust the collimation very little despite moving it around a fair bit. It is quite easy to handle provided that you move the telescope and base separately and don't try to lug everyting around together battery and all....or , in fact, even that is possible in the garden where I can slide the whole set up around easily enough on a sort of wooden sledge. The idea of a manually directable auto-tracking dob was quite new to me but it works very well (for visual astronomy at least) with things staying put in the field of view aftergoing and coming back with a mug of tea ..and just setting up on north and feeding in time, latitude and longitude I found the dumbell OK purely on the basis of the RA and dec readout (of course the goto function would do it better but is harder to keep setting that up when you need to keep moving the scope in a garden with a tree-limited sky view ...so, for me, the manual push to and auto-tracking is one of the big attractions. If you are in a similar position and need to keep moving the scope around and setting up again then it is good feature to have. I don't know much about the Celestron 8SE so I can't comment on your other choice other than to say that my last scope was a Celestar8 SC and, while it served me very well, there is no comparison between the 10 inch and 8 inch views of , for example, the ring nebula and Hercules Globular. 10 inch wins easily for these ...I don't now about planetary views yet and how sharp the faster scope will prove and awaiting Jupiter. Hope this is helpful....

[sam mayo]

250px is amaing scope i love mine never used 8se though!!

[Lenny147]

+1 for the 250px

[davies07]

I'd go for he 250px.

I now own a 10-inch Newt and it shows me so much more (fainter objects with more resolution) than the 8-inch Newt I used to own, that is down to the increased aperture. DSOs in the 10-inch start to have some structure in my light polluted skies, but were little more than faint blobs in my 8-inch.

The 8SE has twice the focal ratio (F10) compared to F4.7 for the 250px. This gives the 8SE higher magnifications, but a narrower field of view and dimmer images. The large central obstruction on the 8SE reduces contrast; so although you'll be able to get higher magnifications on moon and planets with a given eyepiece, the view will be 'softer' - lower contrast.

The advertising for the 8SE emphasises the wonderfulness of the computerised Goto, not the optics. I think there is a message there.

If you bought the 8SE, I think you will eventually get bored with it. And there will be very little you can do to improve, or develop it. It is a closed box

With the 250px you're paying more for the optics. You will learn so much more about the sky and telescopes.

Good luck.

[ollypenrice]

I was going to comment on focal length, too. You have to be careful because, in reality, the brightness of the visual image is only affected by the aperture in visual use, not the focal ratio. (You just use a longer FL eyepiece to get the same effective focal length in both.) The speed of the optics matters in imaging at prime focus, which is a different matter. However, what does arise from focal length is the minimum magnification and maximum field of view that each can offer. Here, despite being bigger, the 10 inch wins. It can go wider. Whether or not that matters is down to your taste in targets. In large telescopes I do like the widest FOV possible and feel slightly boxed in by an SCT. Others don't.

Olly

[Pingster]

Ive got an 8se. I much prefer to use my 12in flextube. The extra light grasp of the 250 will keep you interested for longer and produce a more pleasent view. Dont for one moment assume the higher price of the 8se gives you better optics than the flextube. I dont know where that extra £600 goes tbh! Flextubes have superb optics. I like them so much i have a 12in and a 16in.

The problem with the 8se is that the mount is so wobberly you have to extend the tripod as little as possible. Meaning most of the time your back is bent at low angles when you view at zenith = back pain = i dont tend to use it for more than 2hrs a time. A dob is so comfy to use seated on a stoll i can observe and do often for +5hrs sessions.

The main advantage of the dob is the increased light grasp & resolution, the more the better. An 8in is great if you live under really dark skies, but imo it lacks the light grasp and resolution if you ive in a city

If you go the dob route i recomend: dob + hotek lazer colloimator + wiliam optics binoviewer.

[Demonperformer]

I have owned both of these scopes. Personally, in my circumstances, I found the 10" a big beast and difficult to get in and out of the house, so it rarely got used. The 8SE, although it takes longer to set up, I find easy to carry around, and in my case ease of use means more use.

That said, if you have seen the 10" in person and so know what you are getting and think you will have no difficulties taking it in and out of the house (or wherever you keep it), +1 for the 10".

[Pingster]

If you get the dob, you must buy 4 caster wheels with rubber wheels and screw them to the base. Makes it a breeze to move from

your house/shed.

[Sharpe]

Hi pingster. Please bear in mind ive been doing this much less than u - in fact my total observing time is 0.

However I posted in here with a view to getting my first scope very recently. Like you I had been thinking about the 8SE and was waved off it at all angles by the chaps in this forum. Their main points:

Not EQ mounted so no asteophotography.

Unstable - very unstable due to single arm and will wobble a lot even for visual esp with wind.

Under mounted. Some people suggested that on that mount it would struggle with the 8" scope especially when u load it up with EP's diagonals etc.

Anyway, just reciting what I was told in ny post below:

[Sharpe]

Ps obv my post above was meant for topic author (Dunyb) not pingster - sorry but can't seem to find an edit mode :-S

[michael.h.f.wilkinson]

The higher price of the 8" SCT is easily explained: it requires 4 optical surfaces to be figured correctly (primary, secondary and 2 sides of the corrector plate), instead of 2 in the Newtonian (primary and secondary). Three of the four surfaces are 8" across (the mirror is actually a bit larger than 8"). That adds a lot of cost. There are three advantages of the SCT design worth considering:

1. It is far more compact (the OTA weighs in at a puny 4.7 kg, light enough for hand luggage allowance), so I can take it on holidays with me (even in our old Peugeot 106).

2. It is far more forgiving on the EPs due to its slow F-ratio (and with a 2" visual back gives 1.34 deg maximum FOV, which is enough for most DSOs)

3. It rarely needs collimation, which speeds up set-up time.

If the first is not an issue, and the second and third no big deal (collimation is hardly a dark art), then the 10" will be the best scope for you. I am thinking of getting a bigger scope, and a big dob gives most bang for buck, but I will never get rid of my beloved C8 on its Vixen GP mount.

[AndyZ]

I've recently started out with a 2nd-hand 8SE and in the 4 weeks that I've had it, I've bought some filters, an eyepiece and used it 6 times already. My main requirement was to buy a scope that was easily portable that I could setup inside and then move into the garden. The scope need to be easy pack into my car and go out into the darker skies in the fens. Never used a DOB, but I'm sure it's something to try out when I get a chance

[jonathan]

Not sure what the OP did in the end, but for anyone else who comes across this thread (as I did) looking for a comparison, here is my opinion.

I have no doubt that the 250px will give better views than the 8SE, currently owning an 8SE and a 150P I can see the advantages of contrast and potential magnification that the reflector provides when compared to the SCT.

The 8SE is very portable, even when fully mounted on the 8SE Goto mount, and I really liked that aspect of it when I first started out with it in the back garden. The down side of the 8SE (or any similar SCT) is all the stuff that goes with it - what Celestron don't seem to mention is the requirement for a dew shield, dew heaters (depending on where you live, in the UK they are fairly mandatory), dew heater controller, a power source which is typically a big heavy car battery or (preferably) a leisure battery, then there's the eyepiece case too. If you ever want to use 2" eyepieces then you will very quickly out-grow the Goto mount, so you're looking at a Vixen GP2 (I think) or an HEQ5. That light SCT suddenly comes with a boot full of support gear that takes quite some time to lug out to your back garden and set up.

Still, after all of this, I have had some tremendous views through it from my back garden, there is no X on bright stars from a reflector's secondary mirror supports, and no chromatic aberration on bright planets.

Compare to my experience of the 150P reflector, which I assume will be a similar experience optically to a 250px - higher contrast views for sure, the sky background looks blacker (it is somewhat grey through the 8SE, that could just be my local light pollution I had at the time though, or some dew I wasn't aware of), stars look nice and sharp although the brightest ones do have a big X from the mirror supports, the tube is considerably longer and therefore could be difficult to handle if it is a solid tube, I imagine the flextube would be easier to pack into a smaller space but that increases the set up time and take-down time. An expensive light shroud is probably highly advisable, a dew shield would also be required; if the dob mount is not motorised then planets are likely to wizz through high magnification eyepieces so observing could be tricky when you're trying to tease detail out of Jupiter or Saturn.

I have a box that I can pack the 8SE away in, I would probably have to look very hard to find a box to fit the 250px OTA in, or I would have to build one myself. The dob mount looks like it would be quite easy to transport, but also looks quite bulky and may be tricky to find storage space for. A tripod based mount, whether it is the 8SE Celestron Goto mount or an NEQ6, packs away into a relatively small floor space, and can be put away into a small cupboard for storage.

I have only been playing with my 150P so far this winter, I want to get my 8SE out again now that I have an upgraded dew heater controller (since my old one half-died). A new leisure battery is probably on the cards too so I will be trying to sort out a sensible box for that (probably something with wheels), that would solve my power woes as I have run out of juice in the past which is annoying when there are still crystal clear skies up above. One up for the 150P on CG-4, as that mount runs on AA batteries and will quite happily track all night.

Sorry for going on a bit!

At the end of the day, I still rate my 8SE as my best scope, and a very capable one all-round. I have invested quite a bit towards it, having fitted a 2" diagonal, new crayford 10:1 focuser, 9x50 finder, and all the dew prevention stuff. A lot of this should be transferable to other scopes, so they are investments. The 8SE is not limited to the Celestron Goto mount (one of the reasons why I bought it) as it can very easily also be mounted on any EQ or AZ capable of taking the relatively light weight (mine is just a heavy beast because of all the additions). Between an 8SE and a 250px, an 8SE is surely the more flexible and upgradable, requires less maintenance, and is easier to handle and store (heavy EQ mount not withstanding).

PS... the views of deep space objects were far better through my 8SE than in the 150P. The Orion Nebula was significantly brighter and larger in the eyepiece, and I think it is on this kind of target that the 8SE will win, although Jupiter was very impressive in the 150P I think I was getting the maximum out of it. I don't know if I have got the maximum out of my 8SE yet.

[Dunkster]

The C8 was designed in California for the Californian climate bicbw

And it's not like the additional necessities for the SCT, in our more damp climate, are all that unique... let's look at our friendly neighbourhood Dob.... the flex tubes seem to attract shrouds. The mirrors tend to get fan mods added. You need some means of collimating effectively. A right angled finder or Telrad is added (don't get me started on the inadequacies of Celestron finders!), then there's Wixeys and other gizmos...