9.25" bino telescope - any experience of?

[A40farinagolf]

Hi,

Is there anyone out there who has experience of building / using a pair of binos made from two 9.25" Celestron OTA's please?

Thanks,

M

 

 

[Stu]

36 minutes ago, A40farinagolf said:

Hi,

Is there anyone out there who has experience of building / using a pair of binos made from two 9.25" Celestron OTA's please?

Thanks,

M

 

 

I think this guy has....

[John]

I've no personal experience of such an instrument but here is a thread from the Cloudynights forum on a C8 binoscope build:

http://www.cloudynights.com/topic/500998-building-a-celestron-c8-binoscope-with-matsumoto-ems/

and from the same poster, a C11 binoscope project:

http://www.cloudynights.com/topic/503466-celestron-c11-binoscope-with-matsumoto-ems/

 

 

[nightfisher]

I was only yesterday looking at my 102 skymax and thinking it would be perfect to do this with

[Peter Drew]

14 hours ago, John said:

I've no personal experience of such an instrument but here is a thread from the Cloudynights forum on a C8 binoscope build:

http://www.cloudynights.com/topic/500998-building-a-celestron-c8-binoscope-with-matsumoto-ems/

and from the same poster, a C11 binoscope project:

http://www.cloudynights.com/topic/503466-celestron-c11-binoscope-with-matsumoto-ems/

 

 

Thanks for these references John, they made a most interesting read. I've made a couple of smaller catadioptric binoscopes in the past, they are no more difficult to make than other forms. The compactness is very attractive but I'm yet to be convinced that the long focal length and inevitable high base magnification is ideal for a binoscope. I might revisit this in the future but currently I'm keener on Newtonian based models as they are much cheaper to make. The EMS units used by the author of the CN post are very expensive and the whole SCT binoscope involves 4 reflections per side as opposed to 3 in a reflecting system.   

[nightfisher]

2 hours ago, Peter Drew said:

Thanks for these references John, they made a most interesting read. I've made a couple of smaller catadioptric binoscopes in the past, they are no more difficult to make than other forms. The compactness is very attractive but I'm yet to be convinced that the long focal length and inevitable high base magnification is ideal for a binoscope. I might revisit this in the future but currently I'm keener on Newtonian based models as they are much cheaper to make. The EMS units used by the author of the CN post are very expensive and the whole SCT binoscope involves 4 reflections per side as opposed to 3 in a reflecting system.   

Just throwing a slightly curved ball in here, would a bino scope (twins) be a lot better than a regular bino viewer  in a single scope?

[John]

18 minutes ago, nightfisher said:

Just throwing a slightly curved ball in here, would a bino scope (twins) be a lot better than a regular bino viewer  in a single scope?

I'd have thought it would be. In a single scope the light from the mirror or objective is split between the two eyepieces through prisms and there is some light loss. With a pair of scopes each eyepiece gets a full whack of light from it's own objective / mirror.

Now someone will show the flaw in my thinking I guess

 

[nightfisher]

John your logic sounds firm and right, a pair of conjoined 102 Maks wont be a 204 F13, but they would give more resolution than a single scope and as you say in a twin scope you would have 2 separate light paths rather than the single one split at the ocular, i am giving the the idea of twin small Maks a good deal of thought

[Peter Drew]

Difficult one to answer accurately as much depends upon the aperture, the class of object to be viewed and the observers definition of a "lot" better.

Basically better yes, there will always be an improvement using two good eyes, two signals are always perceived as better by the brain opposed to one of signal and one of noise. For faint objects there is an accepted improvement of around 1.6X, and planetary detail is easier to see. There comes a point however where the added cost of doubling the number of optical components would provide a larger single telescope providing some advantages even with a light absorbing binoviewer. My preferences are for binoviewers for solar without doubt, binoscopes for wide angle DSO's and binoviewers for high resolution lunar and planetary observation.  

[A40farinagolf]

Many thanks for all the feedback and the links have provided food for thought, I didn't realise there would be quite so much machining involved to get them to work and the project looks a bit beyond my ability as I've never made anything optical before.

To keep it simple I thought about mounting them on a side by side losmandy plate with clamps and using the clearance in the holes to achieve collimation.

In theory I've a basic idea of what I need to do from a light path point of view but from a practical point of view the mirrors / prisms  / focussing side of things I don't have much idea so that may be my downfall.   

After starting the thread I contacted EMS in Japan asking them about their products and experience with 9.25 OTA and I await their reply.

Might be better to go own the APM ED100 route :-)

 

 

[Moonshane]

If you are going to the peak star party you could try my binoviewers.