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A little big dob binoviewing last night.

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#1 The Ardent

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Posted 15 April 2018 - 09:51 PM

Last night we had some clear skies. Cloudy nights (the atmosphere,

 not the website) delayed binoviewer testing with the new 18" dob. 

 

Transparency decent, seeing atrocious. Urban backyard , red zone. 

 

First target was Jupiter. At 133x both main belts plus a couple more N and S visible. Fainter belts closer to the poles came and went with the seeing. The GRS was away.  numerous belt irregularities and festoons were apparent. Jupiter was still low and the seeing poor, but the BV gave a pleasing view. Good presentation and comfortable. 

The next test was binoviewer plus Paracorr. It's been my normal procedure to not use the Paracorr w/ BV. The added weight was not a problem and still within focus range. The one issue with my setup- I'm not using the standard TV 1.25" adapter. Have to be carfeful not to hit the Paracorr lens with the BV 2x amplifier nose. 

 

With the Paracorr I have the following magnifications and exit pupils: 

24 Pan 153x , 3mm exit pupil 

18 Delite (modified) 204x , 2.2mm 

14 Radian (modified) 263x , 1.7mm

10mm Radian (modified) 368x, 1.2mm 

 

I tried all magnifications. 204x seemed to be the best choice for the wavering atmosphere. 

 

One great feature about these eyepieces: they're pretty much parfocal. 

 

Next up was M57. The other night I observed it with a single EP. With the BV it appears to float in space in front of the background stars. 

Then globular M5. It's a little dimmer than monoviewing, but I see the granulation and detail easier. 

Last target was bright PN  6572 in Oph. Not as famous as the Ring, but brighter and colorful. Easily seen in 50mm Finder. The green color and oblong shape apparent at 153x. 

 

It it was nice to have one clear night. Only one - it raining tonight. 

 

In in the photo the 18" is the one on the left- shown next to a 36" 

 

 

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#2 BKBrown

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Posted 16 April 2018 - 09:13 PM

Nice kit there amigo smile.png Nothing but clouds and rain here since early Sunday...

 

Clear Skies,

Brian



#3 SchrödingersCat

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Posted 17 April 2018 - 03:01 AM

No GPC?

Did you have to modify the strut length to achieve focus?



#4 The Ardent

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Posted 17 April 2018 - 04:20 AM

No GPC. 

 

http://www.televue.c...?id=63&Tab=_how

 

2x Amplifier Corrector fully compensates for introduction of spherical, color and astigmatism in prisms, along with path length compensation -- maintains simple drop-in installation just like any 1¼" eyepiece, while maintaining optimal optical performance in the finest, fastest instruments such as the Tele Vue-NP101is.



#5 The Ardent

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Posted 17 April 2018 - 04:25 AM

Here's a quote from The Moon and How to Observe It by Peter Grego, page 247

 

"Viewing with  with both eyes allows finer detail to be discerned." 

 

https://www.springer...k/9781852337483



#6 Jeff B

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Posted 17 April 2018 - 12:03 PM

Last night we had some clear skies. Cloudy nights (the atmosphere,

 not the website) delayed binoviewer testing with the new 18" dob. 

 

Transparency decent, seeing atrocious. Urban backyard , red zone. 

 

First target was Jupiter. At 133x both main belts plus a couple more N and S visible. Fainter belts closer to the poles came and went with the seeing. The GRS was away.  numerous belt irregularities and festoons were apparent. Jupiter was still low and the seeing poor, but the BV gave a pleasing view. Good presentation and comfortable. 

The next test was binoviewer plus Paracorr. It's been my normal procedure to not use the Paracorr w/ BV. The added weight was not a problem and still within focus range. The one issue with my setup- I'm not using the standard TV 1.25" adapter. Have to be carfeful not to hit the Paracorr lens with the BV 2x amplifier nose. 

 

With the Paracorr I have the following magnifications and exit pupils: 

24 Pan 153x , 3mm exit pupil 

18 Delite (modified) 204x , 2.2mm 

14 Radian (modified) 263x , 1.7mm

10mm Radian (modified) 368x, 1.2mm 

 

I tried all magnifications. 204x seemed to be the best choice for the wavering atmosphere. 

 

One great feature about these eyepieces: they're pretty much parfocal. 

 

Next up was M57. The other night I observed it with a single EP. With the BV it appears to float in space in front of the background stars. 

Then globular M5. It's a little dimmer than monoviewing, but I see the granulation and detail easier. 

Last target was bright PN  6572 in Oph. Not as famous as the Ring, but brighter and colorful. Easily seen in 50mm Finder. The green color and oblong shape apparent at 153x. 

 

It it was nice to have one clear night. Only one - it raining tonight. 

 

In in the photo the 18" is the one on the left- shown next to a 36" 

I'm surprised (but glad!) to see you got the viewer to work with the Paracor.  

 

Did the assembly kind of hang out a ways from the focuser?  How well did they play together?

 

Regardless, good job!

 

Jeff



#7 The Ardent

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Posted 17 April 2018 - 01:14 PM

I was a little surprised too. I’m supposed to use the standard 1.25” adapter that comes with the P2. The setup shown above was for a different scope , I just grabbed it on the way out. The black 2” adapter is tha Astrosystems negative profile adapter. The BV is supposed to be used the stock TV, which is 12mm higher (have to check the site)

Have to pull it out a little so the BV nose won’t hit the Paracorr lens.

 

The new dob is set up differently from the old and has less back focus. Instead of a FT focuser, it has a Moonlite with Swingfilter. Less focus travel.

Of all the dobsonian filter solutions, I like the Moonlite Swingfilter the best. I would like Starlight to offer this too, and believe me I’m going to ask them this weekend.

 

If you peruse the Televue Binovue website, http://www.televue.c...id=63&Tab=_ause

They made a big change. Now showing the BV coupled to a 2” Powermate. Before the 2x was never mentioned, only the 4x as a 2” focuser option. Two years ago at Neaf I asked them about using the 2x Powermate, and the answer was “why do you want to do that?” My reply I was using it to keep everything 2”. And I liked the PMT better than the 1.25” amplifier. The photo is my Neaf 2016 setup, showing the 2x Powermate and T-thread adapter. Unfortunately not enough backfocus in the new dob to use it..working on that. 

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