100mm ED F9 Binoculars

[Hoges]

Finally got these finished yesterday after I bought a second F9 ED. I figured with the planets lining up for such a good season, it's time I took out the F5 Acromats and put in the ED's (which I've been meaning to do for many years). It's quite tolerant of eyepiece weight - you can go from no eyepieces to a pair of hyperions without upsetting the balance. Colimation is via 3 spring loaded allen key bolts which is fast to do. The weakest link is the cheap 1 1/4" plastic diagonals I've screwed together to allow for IP adjustment - I must see if there is either a better way to do this or get some better diagonals.

[Atmos]

That’s a really neat design John! I used to have a Sky Watcher gold tube 100ED F/9 and it was great, having two of them will be wonderful to view!

[brian nordstrom]

:thumbsup: I like this , what a great design , anyone with basic tools could make this easily .
Well done :D .

Brian.

[Kunama]

Great work John, I think you will love the views, targets like Eta Carina and M42 as well as the moon and Jupiter will take on a new look...

[Hoges]

Cheers guys. There is a noticeable step up in brightness and resolution from just using one of the ED's with a binoviewer. Feels like going from an 80mm scope to a 120mm. I'm getting hundreds of tiny pinpoints in Omega and Tuc47 that were not apparent using just one scope and the contrast and sharpness is much better than the binoviewer in the 6" F8 Acro too.

[Atmos]

Two 100mm has the same light gathering power of 140mm BUT as theyre spread over two eyes I guess Matt would agree that it would be about the same as a 130mm?

[Roger Davis]

Yes and no. If you use a 130 with a binoviewer you lose brightness on Deep Sky objects. With two 100mm objectives using two eyes, you reduce the noise (floaters etc) as your brain does an automatic unsharp mask and noise removal. Your vision is relaxed using binocular vision, so you tend to pick up contrast more readily and resolution is improved. So your 100mm OG's will probably be about the same as a 150mm telescope using a binoviewer.

[SkyWatch]

Thanks for posting this John. I love the idea, and a great DIY job.

- Dean

[Hoges]

Cheers guys. Next time I have the opportunity, I'll put the binos side by side with the 6" F8 and report the differences.

[OzEclipse]

I've looked through Matt's bino's. The aesthetic effect of the bino view, the faux 3D effect you experience is what the view is all about. Fantastic!

All this talk about light gathering is moot IMO. You are arguing about whether one small telescope aperture yields a brighter image than another slightly bigger small scope aperture. If you want light gathering, get a big dob.

After completing his 120 bino's, Matt immediately began building his next 18" dob. That should tell you something about light gathering.


Joe

[Kunama]

Quite right Joe, my favourite views with the TSA120BT are at 30x - 50x using very sharp Tak Abbe orthoscopics. While they perform very well for planetary viewing at 180x using the Tak LE5mm pair, and are perfect for lunar observing, they are still limited to the resolving power of 120mm....

(Horses for Courses........ Regarding the 18" ....... I am hoping to have it ready for first light for the Mars opposition..... progress is slow due to my OCD requiring that external welds must not be visible... :sadeyes:)

[silv]

awesome! Must be fantastic viewing!
I've got 2 questions:
1. what did you use there to accomplish the correct inter pupillary distance? Are those normal prisms?
2. how do you ease the strain on your back when hovering over the eye pieces?

edit: oh, got it. When the binoscopes point upwards you'll be sitting in front of them. Rather comfortably even.

[Hoges]

Thanks Annette,

At the height I have them mounted in my observatory I can either stand comfortably and view or I can use an adjustable stool and sit for the higher elevation stuff.

IP adjustment is by using two pair of standard 1 1/4" diagonals which I've unscrewed the opposing male/female tubes and bolted the bodies together to save some length. You can slightly loosen some nylon thumb screws to rotate the diagonals in the focussers to achieve the desired IP which doesn't upset the collimation too much.

Views are right way up but reversed left to right.

Cheers - J.

[Hoges]

PS: if anybody knows of an actual machined version of my two diagonals screwed together - let me know as the diagonals I've used are only plastic and I've needed to slightly 'pack' one or two of the mirrors to get them closer to exactly 45 degrees each.

[silv]

Thank you for your explanation!

Matsumoto's EMS Systems builds them.
Price list http://ems-bino.com/ems-ultima-series/ from 1500AUD to 4600AUD for a pair.

Product line in English http://ems-bino.com/ems-product-line-english/

[AstroApprentice]

Hi Hoges,
Great work! Here's another option for bino parts:
http://binotechno.com/index_en.html