Bintel 12" Premium Dob

[johnit]

Good afternoon everyone, I am about to purchase my first telescope. It will be used for general astronomy in the Melbourne metropolitan area until I can establish what kind of "go to" telescope to buy. I have been an avid armchair astronomer for 5 years and have decided to take logical plunge into telescope ownership. I would sinceerly appreciate any Member feed back on the Bintel 12" Premium Dob.

Kind regards John Stewart :help3:

[Dave47tuc]

:welcome: John,
I have the 10" version and if you want to move the scope around a lot get the 10". The 12" is a lot heavier to lift and very big to get in a car. :)

Good luck.

[Starkler]

I agree with Dave re portability.
I have the 10 inch , and with dsc attached see no need for goto. Im happy.

[johnit]

Thanks Dave,
Appreciate the comments - have checked out both the size and the weight - will fit in the car quite easily and the weight wont be a problem.....
The only time it will be moved in the car will be when I find an astronomical society to join.....regs John Stewart

[johnit]

Thanks Geoff - will take those comments on board. DSO's are definately something for the future and look forward to seeing how well they work....cheers John Stewart

[iceman]

John, can you make it to the Star Camp in Ballarat in less than 2 weeks?

You'll see 8, 10 and 12" dobs there! And goto scopes, too!

I have the 10" bintel dob and they're great.

[PhotonCollector]

I recently purchased the premium 12-inch dob from Bintel which I converted to an equatorial mount to use for astrophotography (see www.skylab.com.au/pmsa/ (http://www.skylab.com.au/pmsa/) ).

I can say these things about the 'scope:

The 2-inch crayford focuser is possibly the smoothest and best focuser I've ever had my hands on. It has a focusing locking screw and tension adjustment.

The optics are very good to excellent both visually and photographically.

I have little problem carrying the scope (~20kgs), although it is big to crapple. I would not like to have to carry it around frequently and I can't see myself lifting in during retirement age.

The contrast of the telescope is low but can be vastly improved by installing your own light baffles.

The eyepieces that come with the telescope are okay but I don't think they really do the telescope justice. They show lots of coma in the visual field. When I used Televue eyepieces instead the sights are very impressive indeed and the eyepiece induced coma (I think thats what you call it) all but disappears.

I'm basically tickled pink with the 'scope, especially for that price.

Hope this helps.

[davidpretorius]

i have the andrews 10" pretty much due to the freight to tassie being cheaper than Bintel. They are a great company!

Star camp will be a great opportunity at the end of the month, lots of scopes and lots of eyepieces.

I say go the 12", if you have already weighed it up.

Next decision is eyepieces ----> star camp!!

welcome!

[slice of heaven]

:welcome: John

Paul M summed up the OT pretty well. The 'Premium' is a nice package.

[ving]

i have the 8" so if apperture rules the 12" is almost twice as good :)

welcome to the forum :)

[johnit]

Thanks very much for everyones warm welcome..... it is really a great forum.
The first one I have ever participated in. Unfortunately I will be working the weekend of the Star Party but look forward to catching up with as many members as possible at the earliest opportunity.
Your favourable comments in the Bintel 12" has given me a lot of confidence with the purchase.
Thanks once again John Stewart

[ballaratdragons]

Hi John! It is a pity you can't make the Star Camp. You would've been able to feel the weight of my GS12" Dobbie to see if it is managable for you.

I love the light gathering ability of the 12" but I desperately need better EP's as the one provided are pretty ordinary. They work, but can be easily improved upon.

If you need to move it around a lot (by car) I can give you the dimesions of all the GS Dobs if you need them. They are here on this site: http://www.telescope-service.com/dobsonians/dobsonians/dobsoniansstart.html

Good luck with the decision.

p.s. The Bintel dobs are GS dobs.

[Eardrum73]

hi Jonit,

I recently purchased a 12' GS premium dob which is exactly the same as the Bintel one.

What would you like to know about the 12' dob?

Focuser - As with previous post, the focuser is smooth to use.

Fan - The premium comes with a cooling fan attached. I live in north western Sydney and never had the need to use it so far. I may need it come winter time but thats a long way away yet......

The Sping tension - Sometimes I find it hard to put on and to take off, especially in the dark, some force is required, I have to use both my hands most of the time, but for a strong man it should be no problem.
The spring tension only works if the tube is not horizontal. Anything below horizontal level it will slide.

Mobility wise - To me the 12' is not very mobile, its definitely a 2 person job. I find the tube is too large to carry by one person, by that i don't mean the weight (to me its quite heavy though...) but the circumfrance and the slipperyness of the tube makes it difficult for one person to carry. \
I would not reccommend carrying alone even if you are well built, it could easily slip off and the mirrors and tube could get damage.

*I have attached two handles on the sides of the base and makes the base easier for carrying, however it is always better with 2 people. ;)
Mirrors - Comes with pyrex parabolic mirror which means you will get some out of focus bits on the edges. But thats with all scopes that uses curve mirrors, some roughness at some point.

Focal Length - the focal length of the 12' is 1500mm. Which means that you will need an eye peice of at least 7mm fl to get 200x magnification. Something to keep in mind.

Eyepeices - I think Bintel supplies a 30mm, 15mm and 9mm with thier premium. I could be wrong. But these are all GS eyepieces, and to me (cus I wear eye glasses while viewing) the smaller fl eyepeices with small eye relief becomes quite a chore for me. So as with any telescope you purchase, a further investment is needed in eyepeices. but hey, maybe you don't mind the small eye relief that much.

Honestly, I have recently looked through a meade UW eyepeice, and a GS/Bintel wideview eyepeice, and they looked identical. I just could not tell the difference. One retails at 280 to 300 quids while the other I think about 70 to 90 or something like that.
So from this experience, I would have to say that GS eyepieces are quite alright in quality.......
I haven't looked through a televue though.... so I dunno what that is like..:confuse3: but I heard it was the best eyepeices you can get your hands on.....

Anyway... I hope this helped. Feel free to post and ask more questions about GS/bintel 12' dob. I will answer them to the best of my nub ability.

[ballaratdragons]

Eardrum and Johnit,

You don't carry the whole scope and base at the same time!
I agree though that it would be difficult that way.

I take the OTA off the base and set it aside, then take the base out (very light) and place it where I want to view from. Then I carry the OTA out in a vertical position by holding the large black bearings (fairly light), then place it back on the base outside.

To pack up I just reverse the order. Bring the OTA in and place it safe, then bring the base in and then put the OTA back on the base.

There is a way to make your springs easier to get on and off. I turned mine upside down. I placed a post in here somewhere on how to do it.

[Eardrum73]

No, I always detach the tube from the base and vice versa when I am bring it back it.

The only time i ever move the unit as a whole is when I want to move it to a nearby location (like 5 to 10 feet apart) there are two of us around and we lift the unit via the handles I attached on the sides of the base. (Imagine a Celestron star hopper with the tension handles).

What I meant on my past was only for the tube itself only. I find it hard to (impossibe for me) to carry alone. I always need someone else to help me with it. Its quite large by itself and slippery as well. So i am not sure if strength alone is the answer, more of it has to do with grip than strength i think (although for me its both!)

Maybe a RL front row forward can do it.... :P .

[ballaratdragons]

Lol!

I was only a Hooker in RL and a small one at that.

Yes, I've heard others say they have trouble carrying the 12" OTA. I suppose if I had to carry it too far I would buy a trolley.

[Merlin66]

Any one had the opportunity to compare the 12" Bintel optics with an original Coulter 13.1", f4.5 Dobsonian set????

[ving]

life has only given youone back.... look after it.
it'd be a trolley or nothing for me re the 12".

[Eardrum73]

A trolley would help, but again I would still think it would require 2 people to lift it onto the trolley. Unless you have a shed, trolleying the thing in and out of the house would be a nightmare.


A hooker? you originally from the Cross Bdragon? :P

[ballaratdragons]

LOL!!!!! I lived in Kings Cross for 2 years whilst learning to be a Tattoo Artist! But no connection to my position on the field.

I carry mine from inside the house, down some steps, through the sunroom, through the dogs, across the backyard (dogs tangling in my legs) out the back gate and through the sheep poo into the paddock. Just call me Hercules (with a busted back) lol!

By the time I reach the paddock the thing weighs 14 tonne!!! :lol:

[Eardrum73]

LOL!!! LOL!!! ...... oh dear...:rofl:

How do you do it?!!!???

This is the lesson in life guys, play rugby league!

So you can be portable with your dob when you retire from the game!

Join up now its not to late!

[ballaratdragons]

Hahaha, and grow a thick neck! (or is that 'no neck'?)

Johnit, if you are able to arrange time with some members in here try out the scopes thay have. No-one sells GS dobs in Victoria so you can't go to a shop and compare.

[davidpretorius]

or go a dob buggy???

[Roger Davis]

Sorry for the late post to this discussion , but I thought that I had better correct a few misconceptions about optics etc.
It doesn't matter what the substrate is of your mirror when you are using it! Truly! An extra couple of minutes of cool down makes not that much difference. The substrate does matter when you are MAKING a mirror as you have to wait for the polished mirror to cool down between testing. Hence: CERVIT, ZERODUR & PYREX (Duran50).
Eardrum73 said:
"Mirrors - Comes with pyrex parabolic mirror which means you will get some out of focus bits on the edges. But thats with all scopes that uses curve mirrors, some roughness at some point."
Who told you this? I am sorry to say that you are wrong. You will not get "out of focus" bits at the edges just because it's pyrex, unless you used pinking shears to cut out the disc. A parabola will be generated from edge to edge in the same form. That's why we do zonal testing on mirrors as the defect will form in a radius from the centre. We correct the 70% zone or the 30% zone, we never correct for radial errors. as they hardly ever occur (unless you are using plate glass and hold the mirror before immediately polishing it, or if the disc has internal strain).
As for the old Coulter scopes, their mirrors were ok at the time, as were their prices, but I remember seeing quite a few that were undercorrected as they assumed that once mounted the mirror would sag to the correct figure, wrong!
The Coulter scopes used a one bar spider. It was about 5mm thick and the collimation of the secondary was done with one bolt which was mounted off axis to the centre of the secondary mirror cell. This system did not make collimation fun.
The Coulter mirror was not mounted terribly well either. Even a six or nine point flotation system would have been better than the way they did it.
So actually the BINTEL or GS Optical tube assemblies are much better with their four vane spiders, good mirror cells and collimation (even if they are three point collimation and not orthogonal).

[chunkylad]

Hi Eardrum

When using my trolley, NO lifting is required. Just slide the baseplate of the trolley under the base of the dob! QED!!!;) A couple of occy straps, and Bob's your male relative. I'm a big-ish bloke, but I don't need to manhandle my dob at all, the trolley does all the heavy work.

Cheers