Skywatcher Skyliner 250PX Dobsonian Review / First Light

[Polar Bear]

The Why?

I decided to give observing (and a little simple imaging) another shot after an enforced absence of 12 months or so. My previous scope was a Celestron C8 Ultima which I found superb for Lunar and Planetary but somewhat lacking on DSOs. I have also owned 4" and 5" refractors and 6" reflectors on EQ and Alt-Az mounts so fancied trying out a large Dob for a change to see what could be achieved on DSOs from my terribly light poluted garden in central Lancashire. As we all know Dobs do offer a lot of aperture for the money but whether using one was pleasurable and satisfying was an unknown to me.

Why the 250PX? It simply came along at such a bargain price I could not ignore it as we shall see below.

The Purchase

I have bought lots of equipment over the years, all of it secondhand, with the exception of a few finders, adapters and EPs. Sources have been local ads, UK ABS. eBay and SGL of course. Luckily (or through good judgement and experience) I have never had a bad experience. I am always watching eBay and the 250PX was advertised with no reserve and was a mere 40 miles away. What swayed it for me with this one was that it had obviously had little use and looked in excellent condition from the photographs.

The real deal clincher was that it came with extra EPs which were a X-Cel 10mm, a 2" Panaview 32mm and a 2" Meade 56mm Super Plossl. Additionally a T2 adjustable camera adpter was included along with 4 astro books, a large planisphere, a homemade Baader film Solar filter and all the original Skywatcher EPs etc. It did come with an inexpensive Chinese Laser Colliminator but this fell apart!

Everything (apart from the laser) is in excellent condition and a quick fag packet calculation would put the whole lot at around £700 if bought new. I paid well less than 50% of this price. I often wonder how many people buy telescopes only to sell them on at a massive loss months later?

The Scope 

The scope is not as large or as heavy as I expected it to be. My C8 on its mount was very difficult to move around as a complete unit (top heavy) whereas the 250PX can be moved as a single unit. However, I am reasonably strong so would advise moving the 250PX in 2 seperate parts to avoid accidents. This is easily achieved and taking the tube OTA off the base and remounting is a simple and straightforward task. The pivots that screw through the mount into the OTA can be used as handles to enable the OTA to be moved safely.

The mount itself is simple. Getting the correct tension on the Altitude is easily achieved. I just keep the pivot without the bearing finger tight and adjust the tension with the pivot that has the roller bearing. The action is quite smooth but does take some getting used to as I find myself contantantly slackening and tightening the pivot during use. This works for me but you may just want to set the friction and leave it as is whilst viewing. The Azimuth is a different matter and I have found it difficult to get a reasonable 'feel' to the mount. This is an area that can be improved and I will be fitting a lazy susan bearing soon. The standard focuser is OK for visual and can be adjusted. I have found that with the 2" EPs the rack tension adjuster underneath needs to be engaged a little to stop the EP moving inwards if you accidently catch the EP. I dislike the finder and the position you need to be in to use it. Either a Telrad (and initially using the 56mm EP) or a Right Angle finder will resolve this. Although used and having been transported the collimation seems fine.

To sum up, the 250PX is a simple 5ft tall light bucket, that is easy to store, easy to move about, and can have you observing in minutes, which is surely a great bonus.

In Use

Apart from the aforementioned smoothness issues on the base and the contortionist finder, the 250PX is a very simple scope to use for visual and I can be viewing in minutes. For objects around the celestial equator and ecliptic (Sun, Moon, Planets) seated viewing is a pleasure after using EQ mounts. I have already sat comfortably for hours viewing Orion, the Double Cluster, the Moon and the Sun. This is a great bonus if like me you are no spring chicken, but it also allows you to stay still comfortably to get your 'eye in' over a long period. Once used to the upside down inverted image nudging the scope to maintain your view becomes second nature. Viewing higher and towards the pole is a different matter. I am 5' 10" and find myself stooping awkwardly, maybe a viewing stool or higher chair will alleviate this problem.

Obviously there is no 'goto' on this scope but I have never had this feature on any of my scopes and find star hopping with the aid of Stellarium before I go out, and Starmap on my Nokia phone to be good aids. I prefer not to have goto as I think you learn the night sky and are able to recognise the major constellations and stars better without it, but we won't go there

So an easy to use, generally comfortable scope that will allow hours of viewing.

First Light

My viewing location is a small South facing garden on a modern estate with houses in all directions. My view to the East is obstructed to about 15 degrees and to the South and East less so at about 10 degrees above the horizon. With an LV Mag of 4.3 (Bortle 8) the light pollution is pretty bad. Although not ideal viewing over rooftops, it is very sheltered and only 6 paces from the kettle. I also seem to suffer little from dewing which could be down to the expanse of brick and concrete all around me.

I first used the scope on the 29th for some Solar White Light viewing. Using the Panaview 32mm (37.5x)  the Sun (whole disc) occupied about half of the EP and was extremely sharp. I could even make out faculae towards the limb which was a result. It will be interesting to see if I can image this in the weeks to come. Using the X-Cel 10mm (120x) was a little too much for visual with atmospheric turbulance making accurate focussing difficult.

On the 30th I had a lovely clear sky and started observing around 10pm. This was going to be a real test with a bright half Moon adding to the LP. An obvious easy choice to start with was M42 the Orion Nebula that was SSE at this time of evening. Using the Panaview 32mm gave pinpoint stars across 70% of the view and clearly visible nebulosity with direct viewing that enabled the shape to be determined easily. Using averted vision gave a large increase in brightness. I could even detect a slight 'blueness' to the nebula. Limiting magnitude on surrounding stars was around 9.5 -10 which is pretty good for my very light polluted site on a Moon lit night. Going up to 120x with the X-Cel 10mm gave a bigger object but did not seem any sharper. Next time out I will be trying for the Flame and Horsehead Nebulas.  Hopefully Santa is bringing me a Baader Hyperion 8-24mm which will help fill the gap between 10mm and 32mm. I also had a quick look at The Double Cluster in Perseus under Cassiopeia but started to get a stiff neck from stooping at the EP. The stars were pin sharp and a joy to see at 37.5x magnification.

To finish off I almost blinded myself viewing the Moon with the 10mm X-Cel. Views were very sharp and crisp especially around the Lunar Terminator but travelling across my field of view too fast for my liking. Using the 32mm Panaview showed the Moon gloriously framed in the night sky by which time it was midnight and about to dissapear over the rooftops.

So in conclusion I would say that first impressions are excellent for visual and I am looking forward to improving the scope to make the viewing experience more enjoyable. Buying at such a budget price has certainly put a smile on my face. Next I will be trying some Moon and Jupiter imaging with the scope.

Paul

 

 

[knobby]

Lovely scope , nice report

[Polar Bear]

Lovely scope , nice report

Hi Knobby, how do you find the 250px compared to the C8 on DSOs? I miss my C8 Ultima as it was almost perfect for Lunar and Planetary visual and imaging.

[John]

Good report on a good scope !

Good luck with the Horse Head and Flame nebulae - I can just detect the latter with my 12" and a Lumicon H-Beta filter but the HH has eluded me thus far.

A good tester at the moment is to pick out the E & F stars in the Trapezium in the heart of the Orion Nebula - they seem to respond well to an 8mm or 10mm eyepiece.

[Paul73]

Nice scope.

Not wanting to put a damper on things, but the Horse's Head or the Flame will be a step too far in any sort of light pollution

M35 through M38 will be great with the extra inches. Obviously M31, 81 & 82 will look good.

Get yourself a Right Angle Corrected finder. I can't understand why they ship them with straight through finders. This will make a massive difference to your viewing pleasure.

Just wait until 3am when most of the lights are out and Leo / Virgo are high....... Galaxy heaven.

Paul

[knobby]

Hi Knobby, how do you find the 250px compared to the C8 on DSOs? I miss my C8 Ultima as it was almost perfect for Lunar and Planetary visual and imaging.

Pretty hard to quantify as I've never taken them both out together ... But in the light polluted back garden using Orion neb as a guide , I'd say that I van see about 70% of what the 250 shows with the C8 ...

Not scientific but an idea

[Polar Bear]

Pretty hard to quantify as I've never taken them both out together ... But in the light polluted back garden using Orion neb as a guide , I'd say that I van see about 70% of what the 250 shows with the C8 ...

Not scientific but an idea

Thanks for that. looks like a C9.25 may fit the bill for me? As much as I am enjoying the 250px a big C series on a fork mount with a wedge is still beckoning.

[kev100]

Great review (and what a bargain!). I bought a 250PX back at the beginning of the summer, and I absolutely love it! It's easy to move, easy to use, goes in the car, holds collimation very well, and gives fantastic views – I had my first view of the Orion neb through it the other night and I was blown away ... the difference in detail and brightness compared to my previous scope  (a 5 inch newt) is immense. 

You mentioned making some improvements, and I'd be keen to hear what you do. Although fine as is, there are a couple of mods that I've seen recommended.

Although replacing the focuser with a nice dual speed one would help things, the standard one can be improved. I can't find the website now, but filing the slot in the focuser draw tube flat is a good idea (I've done this, and it's made a big difference to focussing - it's much less sloppy than it was). Also, I've taped a bit of camping mat inside the base box to stop the bottom of the tube knocking against it when it's upright.

A right angle finder would also improve things. Finally, and I haven't done this one yet myself, but sealing all the joints in the base with waterproof/silicone sealant is also recommended.

Cheers,

Kev.

[swamp thing]

Great review

I'd echo the comments on the nags head and flame nebulae, just gonna be very tricky from any sort of LP garden but hey ho you never know until you try.

I would recommend a drum throne for your seating arrangements, lovely sand comfy and most have ample adjustment to allow you to be happily seated in comfort from horizon to zenith with a 10" dob.

[Polar Bear]

Lazy susan and a right angle finder on their way thanks to Astroboot.

I will also be fitting a SCT camera mount for my Nokia so I can use the Skymap app as a search aid.

Having done a little research on the Nags Head and Flame, and taken onboard everyones comments, I don't think these are at all possible from my LP garden.

Paul

[TractionMan]

Very nice report and very nice scope. Telrad + RACI finder will improve it alot!

[niallk]

Snap! Great scope + write up Had mine out at 5am this morning to see the GRS. Btw I find the Lacerta 10:1 focuser upgrade (€69) very much worth it.

Best of luck!

[estwing]

Great scope and welcome to the Dob Mob

[rory]

Great write up. I too have just grabbed a s/h 250px . I got it at a great price although it's sbout 7 years old . Actually I think the older version has better collimation knobs than newer versions.

I have to echo your thoughts on the Finder . I previously had a 8 " dob and it came with a right angled finder which was very comfortable to use .

This 10" come with the standard straight through finder and although I've not used the scope for any real length of time as yet , I've found the straight through is a serious flaw.

Telrad and Raci is the way I'm going .

Again on my old 8" I fit a lazy Susan . Very easy to do and made a big improvement . You do need to add some friction of some kind as the bearing alone means one nudge and the scope will spin round like a waltzer at the fair !

I'm really looking forward to using this scope in the new year . I'm currently trying to decide which e/p focal lengths will give me best spread with about 3 eyepieces.

[kev100]

Hiya, I tracked that focuser improvement down I mentioned : 

Definitely improves the focuser action.

Kev.

[Polar Bear]

I'm really looking forward to using this scope in the new year . I'm currently trying to decide which e/p focal lengths will give me best spread with about 3 eyepieces.

I have gone for a Baader 2" 8-24mm zoom which should cover most bases. This will mean not having to change EP's and it supposedly works OK with an F5 scope.

Father Christmas will be bringing it me along with a Skytee 2. Although I have fitted a lazy susan type bearing to the dob base I still dislike the mount having been used to the smoothness from EQ and Mak fork mounts.

I will review both EP and Skytee in the new year.

[rory]

I struggled with the Hyperion zoom with my old set up 8" sw dob. I didn't like the fov on low power.

But very convenient to be fair. To compensate the low power tube like feel I added a Hyperion 31mm aspheric , that was a very nice eyepiece .

[Polar Bear]

I struggled with the Hyperion zoom with my old set up 8" sw dob. I didn't like the fov on low power.

But very convenient to be fair. To compensate the low power tube like feel I added a Hyperion 31mm aspheric , that was a very nice eyepiece .

Have you still got the Hyperion 31mm? if not I can recommend the 2" Panaview 32mm. It has a 70 degree field and sharpness is good over about 75 - 80% of that. Nice twist up eyecup as well.

[MattJenko]

I also have the Hyperion Zoom and find it does struggle a little in the 250px compared to some other EPs. It is very far from bad though. I have a MaxVision for the wider views and am slowly getting fixed length EPs to cover the rest of the magnification ranges. The zoom works lovely in my 80ED though, so think it may be the F4.7 is at the edge of it's performance ability. It is still a step up from the EPs that came with the scope though and the ease of use is seriously handy.

[bish]

Nice report, it's a great scope. I am the same height as you and have a fairly high stool which makes observing much more comfortable (although an adjustable one would be even better). The flame is fairly easy from a dark site (not actually looked for it under light pollution) but the HH is a different matter all together. A H beta filter, no light pollution and perfect transparency you might just glimpse it.

[John]

I found the Hyperion 31mm Aspheric quite dissapointing in my F/5.3 12" dobsonian in all honesty. It's not going to be any better in a 10" F/4.7 dob I'm afraid.

The Baader zoom was quite a lot better corrected towards the edges of the field of view than the Hyperion Aspheric was, though still not perfect.

A F/4.7 focal ratio is tough on eyepieces so some compromises will be needed unless you are prepared to shell out on a coma corrector and something like Explore Scientific or Tele Vue wide field eyepieces.

Alternatively you could avoid wide field eyepieces and invest in some Tele Vue plossls which are excellent performers within the constraints of the plossl design.

I still tend to feel that the guideline "wide field / low cost / sharp across the field in fast scopes - pick any two" is valid.

[rory]

Glad you mentioned that John . I used the aspheric in a f/6 8" . But now I have a 4.7 I'll know to avoid.

Guideline does make sense.

[Polar Bear]

I've been busy today....

http://stargazerslounge.com/topic/232141-de-dobbing-a-250px-and-upgrading/