Skyliner 300 or 350 FlexTube Synscan

[pleiades]

No, as the title says 300 or 350 FlexTube Synscan. Those are Dob mount& FlexTube.

[Rossco72]

The base design for the 14" and 16" is different from the 12" and smaller. The larger scopes have a collapsible box design because they are too large to fit through doors and in cars etc whereas the 12" and smaller are fixed.

As for the variance in quality, i don't know. Maybe I just have a poor one, maybe I just haven't been able to iron out the problems but I have 2 other skywatcher goto mounts and they pretty much work out of the box so I haven't experienced this level of poor performance by a skywatcher before.

Cheers

[Priastro]

That's mean that the 12" mounting comes mounted from fabric and is not demountable? Another question is about balancing of the 14", switching from a heavy eyepiece combination like nagler 31 + paracorr to a small eyepiece. How sensible is the 14" in the balance? Do you Rossco42 have tested with high magnication eyepieces. I see you have a nagler zoom there?

[pleiades]

Thank you Stuart.

Priastro's question is very good. This is something I didn't count. 12" is not demountable?

About balancing I thing because of the tracking system must not be very sensitive in the balance. It's not like a simple Dob base.

Anyway even in small dobs we can use small counterpoise (I used some magnetic).

[Rossco72]

No the 12" OTA can come off the base but the base is constructed from screws which aren't designed to be taken apart and built again.

The 14" and 16" bases are put together with bolts which are designed to be disassembled many times over as there is no other way to move the base from one place to another.

I use a 41mm panoptic and 26mm nagler and as you say a 3-6mm zoom. I purchased a magnetic weight which i attach to the OTA as needed to achieve balance for any particular EP or camera combination.

Cheers

[Priastro]

Thank you Stuart. Where did you bought such a magnetic weight? Did found it meaningful to zoom in down to 3mm if now the seeing permitted it without the image suffering?

[pleiades]

Thank you Stuart. Where did you bought such a magnetic weight?

Until Stuart answers you, I can say that I did a very easy construction from a small carton box. I fill it with iron bars and close it with tape. On the downside I glue 2 refrigerator magnets.

I use 2 of them for counterpoise.

[Rossco72]

PlateMates Magnetic Donuts (1.25lb) 2 x 566g Plate(s) on eBay (end time 31-Jan-11 18:41:38 GMT)

From ebay!

[pleiades]

Stuart I repost here.Can you tell me please what is the height of eyepiece when 14" telescope point at zenith? I can't find the answer anywhere.

[Priastro]

Thanks, that is a very good advice. I have measured and find i possible to get the 14" back in a Volvo V70, the mounting undemounted, but there vill be more room for further luggage with the 14" demounted than the 12" undemountable. By myself I reflect the choice of the 14", the 12", Orionoptics VX12L 1/10 pv and the celestron C11. I have already an EQ6 and an C8 for my balcony. I want beside better deep sky performance also a planet performer in a transportable size. I think the Orionoptics is the best choice.

[pleiades]

From Stuart photos I have to assume that the height of eyepiece when 14" telescope point at zenith is somewhere between 170 - 180 cm?

Also does anybody know what is the equivalent height for a 300P synscan?

Thank you

[astronymonkey]

Ive been contemplating these scopes myself but im waiting for the price of the 400p to be released first.

My main priority is light grasp, meaning the 400p may fit the bill but I would need to compare the price with the lightbridge 16 and factor in if the goto is worth the extra.

As for size, well I think it may be on the limit of what I can carry but as long as it fits in the car then Im sure I could manage and as for home use I plan on making a watertight box to cover it so I can leave the base outside ready for use.

At f4.4 though I know its going to punish eyepieces so Ill probably buy something like a WO UWAN 28mm to get the most from it.

Astronymonkey

[pleiades]

My main priority is light grasp, meaning the 400p may fit the bill but I would need to compare the price with the lightbridge 16 and factor in if the goto is worth the extra.

Let's say will be about 2300. What is your opinion? Worths the extra?

As for size, well I think it may be on the limit of what I can carry but as long as it fits in the car then Im sure I could manage and as for home use I plan on making a watertight box to cover it so I can leave the base outside ready for use.

Astronymonkey

hmm.. I thing this is not a good idea. Even if the box is really watertight, damp will stand on the walls. The wood of the base is not solid wood, and is very easy to absorb humidity. I beleive after a little time will start inflate. Take care and ask a pro, first.

[Priastro]

How about the manual movement of a goto compared with a one with no servo motors. Is there a clutch, so the OTA i free?

[Rossco72]

Stuart I repost here.Can you tell me please what is the height of eyepiece when 14" telescope point at zenith? I can't find the answer anywhere.

It's about 1650mm give or take. I am just about 6 foot tall and it is at my eye level.

[Rossco72]

How about the manual movement of a goto compared with a one with no servo motors. Is there a clutch, so the OTA i free?

Manual movement is stiff but doable and once you get close you can use the handset buttons.....

[MartinB]

I have a 300mm skyliner dob and am very happy with it. It just avoids being too big to put me off setting up in marginal conditions or for those brief clear spells. I wouldn't want to go bigger unless I had some sort of set up on rails or a trolley.

This scope gives noticeably better planetary views than my 10" LX200R - both contrast and resolution although I would love tracking for these high mag situations.

[pleiades]

It's about 1650mm give or take. I am just about 6 foot tall and it is at my eye level.

Thank you Stuart

Please does anybody know what is the equivalent height for a 300P synscan?

[Priastro]

That sounds very good, the 300 is better than 10" LX200R in high mag planetary viewing, There must be good optics.

[astronymonkey]

Let's say will be about 2300. What is your opinion? Worths the extra?

hmm.. I thing this is not a good idea. Even if the box is really watertight, damp will stand on the walls. The wood of the base is not solid wood, and is very easy to absorb humidity. I beleive after a little time will start inflate. Take care and ask a pro, first.

With this I suppose it will depend on if the drive is good and how accurate the drive is with regard to tracking. I think this would make the scope more useable when showing others the sky rather than having to keep nudging the scope to keep things in view. Goto isnt essential but I would hope it woud allow me to see some of the faint fuzzies that have always eluded me, but then again Ive spent 25 years star hopping with a driveless homemade dob so maybe I just fancy spoiling myself

For £500 extra over the lightbridge it would be getting expensive , and at £1200 over a second hand LB Id have to have a good think... and consider making a platform drive- but that would raise the eyepiece height to the point where a step would be needed at the zenith which wouldnt be ideal

As for keeping the base outside, ive been thinking about if I kept the base in a garage or Observatory then it would still be undercover and unheated In a similar way to if if I made a bespoke cover/ Box to protect it. Although I understand what you mean about damp and dew that may have formed on the base during use being a potential problem once coverd back over.

Astronymonkey

[Priastro]

I wonder about the secondary mirror size. According to skywatchers homepage the secondary for the 350 is at huge 93 mm wich will give over 26% obstruction. I think this is not correct spec. For the 300 it is 70 mm wich will give 23.3 % obstruction.

Is that correct spec?

[pleiades]

With this I suppose it will depend on if the drive is good ...... a potential problem once coverd back over.

Astronymonkey

For platform you have right the raise of eyepiece height is a big problem.

I agree entirely with all of the above you mention. To add something to this, for me the 500 extra is a cost that worthing. I mean is not much, first for the tracking, witch I consider the most important. Secondly, for the the GoTo. The accuracy is a matter, but as Rosco72 and Albireo380 says is in high levels.

I use a Newtonian on a equatorial GoTo mount. And 95% of my observing time I search with star hopping. It's a big pleasure. After time I spend on a faint object that can't find, GoTo gives me this extra certainty, if I am on the wrong spot or if tonight is not the best sky to view this object.

[pleiades]

I wonder about the secondary mirror size. According to skywatchers homepage the secondary for the 350 is at huge 93 mm wich will give over 26% obstruction. I think this is not correct spec. For the 300 it is 70 mm wich will give 23.3 % obstruction.

Is that correct spec?

Perhaps the difference it's a mater of mirror dimensions and focal length. In 300 is f/4.9 and in 350 f/4.5

So perhaps f/4.5 give this huge 26%.

It's a good question and I like also an answer for this.

[astronymonkey]

Good point but the obstruction would be dependant on the area , not the diameter.

At 350mm the area of the primary would be 967cm and the secondary (at 93mm) would have an obstructive area of 68cm meaning only a 7% obstruction by area.

At 7% this seems more reasonable

Astronymonkey

[Priastro]

It's two ways to measure obstruction one is by diameter and the other is by area I see mostly that the measure with diameter is common. More important is to know which of them is in the context.

Now here I have found one answer:

Skywatcher Skyliner-355PX / 14' f/4,5 Dobson einschiebbarer Tubu

They will tell us 80 mm secondary which will give 22.5% obstruction by diameter. That seems more resonable. Maybe Stuart or Tom can verify. They will also tell us of a rockerboxweight of 50kg and the OTA 32kg, which is not true.