The Veil and some DSO chasing with binoviewers

[Ships and Stars]

Hi all,

Finally managed to slip away last night for a quick observing session near home. Family duties have been keeping me flat out at nights and besides, the weather - as many of you know -  has not been great past few months. I've struggled to get a decent night out with no moon when it's not literally blowing 30-45mph.

Something I've really wanted to do for awhile is play around with the binoviewers and the shorter 'binoviewer setting' on the 300p flextube on several DSOs, namely the Veil.

I also took my 20/40x100mm Helios obsy bins on the giant DIY Kraken scaffolding tripod and my 15x70s, so the car was literally stuffed full.

I've been on a two-eyed observing kick more and more lately - the joys of binocular summation! As some of you may know, the SW flextube dob binoviewer preset allows binoviewer use without glass path correctors or barlows, thus giving a much wider FOV at lower mag.

Normally I use a Baader clicklock 2" to 1.25" adapter over a normal 1.25" adapter to move the BVs as close as possible to the secondary to reach focus. Well, the binoviewer preset on the 300p works so well, I had to revert back to the normal 1.25" adapter to move the binoviewers away from the secondary and increase the light path. This was without a barlow or GPC! This tells me perhaps I can take some accurate measurements and drill a third set of indents in-between, to keep the total obstruction of the secondary as low as possible, as presumably moving it closer to the primary creates a larger central obstruction and reduces brightness/contrast.

I also set up the Helios 20/40x100mm obsy bins to compare against the 300p in binoviewer mode, but didn't get to push this too far last night as it moves too freely for my liking. I'll need to install a better altitude bearing/braking system to stabilise the bins and add a red dot finder as pointing them accurately is a lot trickier than I imagined.

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The Observing

Anyway...my hands were full. And it was our first cold snap of the season.

I arrived onsite very early at 6pm, set up and surprise, surprise, some last-minute cloud appeared. With a good forecast still predicted (FLO CO/Met Office/Ventusky all showing clear)  I waited for it to clear in 0C or 1C temps. And waited. And waited. And some more...

Finally, after two hours or so of watching Deneb vanish in the dense high level haze and suddenly reappear, everything was suddenly super-transparent! And not a hint of wind. At last!!

Time was limited by this point, so first port of call was the Veil with 32mm Revelation plossls in the WO binoviewers - remember the exit pupil is reduced with binoviewers so these behaved probably more like single 20-25mm EPs.

I thought I had screwed in the 1.25" Astronomik OIII on the BV nose, so I was a bit disappointed when the E & W Veil were rather faint and lacking contrast, but there nonetheless. Maybe this wasn't going to work so well... Then I saw the tell-tale green/red stars and instantly knew I had used the UHC instead of the OIII. I call this the 'Christmas effect' and it's just the nature of this particular type of UHC filter. 

So I swapped over to the OIII and the stereoscopic two-eyed views of the Veil were excellent, including Pickering's Wisp. Plenty of details, structure, brightness and contrast, no eye strain compared to using one eye, and best of all, the 32mm plossls gave tons of eye relief, so I could easily wear my glasses and not lose any views (or my glasses) in the process. In fact, I had to hold my head back slightly. Not touching the EPs meant the scope was perfectly still. Sitting in a chair, this made for excellent observing! I could fit about 50-70% of each side of the Veil into the FOV, so with a little nudge, I could easily sweep across each side. I also swung over to M57 for a nice stereo look as well. A viewing hood when binoviewing DSOs is essential headwear to block out all stray light from the sides - a hood improves the experience dramatically and gives that stereoscopic spacewalk feeling, even with narrow FOV plossls by isolating the views.

I then fully extended the truss rods to the normal settting and dropped a single 17.5mm Morpheus with OIII into the focuser to compare views. This was also excellent, naturally it was a fair bit brighter and crisper, but overall not as relaxed, not stereoscopic and not as immersive as using binoviewers. Still, single eyed viewing will squeeze the max brightness out of your particular scope, just that binoviewers vs single EP both have their pros and cons.

While the single 17.5mm was in, I went over to the Crescent Nebula and was rewarded with good structure and a view with nearly filled the EP. I had forgotten how large it was! 

But what I really wanted to do was try for the Cocoon with binoviewers...

The Cocoon IC 5146 is what I call my 'observational nemesis' and is probably the most challenging Caldwell object by some margin. It took me ages last night to find the dark lane as I was getting pretty tired and had a lot of difficulty. At last, I got the dark cigar lane in the binoviewers with no filter, and dashed to grab my Hb filter for the win. In doing so, I bumped the scope and it moved way off target naturally! Spent ages trying to get the dark lane back - never did with certainty, but passed M39 about half a dozen times and my hands were going numb by this time and I was getting wobbly, so will have to leave attempts at binoviewing that for next session. I wanted to compare it to the surprising views I got with the 15x70s a month or so ago under very dark skies and make sure it wasn't M39 I was seeing! I do think I bagged the Cocoon with the filtered bins though.

More to come on the binoviewers and the obsy bin comparison once I've sorted a few bits.

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Binoscope Fever Sets In...

What's worse than aperture fever? Large-aperture binoscope fever of course! 🤣

While I had great views through the binoviewers of the Veil, the brighter view with a single Morpheus really makes me want to build a binoscope. I'm tempted to keep my eyes out for another 300p flextube and have a bash someday...

I've been reading up a bit on binoscopes, and despite their incredibly stringent collimation and complex build/set-up requirements to achieve a nicely merged image, binoscopes, in my humble opinion, must be the ultimate DSO observing machine. You get a wide field of view, but a gain in aperture similar to a much larger scope (1.4x - ish), all with the benefit of binocular vision. Add night vision tubes someday and...

Someday indeed...

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PS pics below of the holes in the 300p truss rods for the binoviewer setting - dead simple way to reduce the light path by 115mm!

Cheers all 👍

 

Edited November 20, 2020 by Ships and Stars

[scarp15]

Great, interesting approach and modifications with a plethora of equipement. Patience paid off, last shout perhaps of the summer season targets. Orion is just around the corner, well depending on weather and lock down circumstances for any trips outs. 

[Ships and Stars]

2 hours ago, scarp15 said:

Great, interesting approach and modifications with a plethora of equipement. Patience paid off, last shout perhaps of the summer season targets. Orion is just around the corner, well depending on weather and lock down circumstances for any trips outs. 

Thanks Iain, I would have stayed and gone over to Orion as it was up shining brilliantly when I returned home, but from this particular spot the hillside behind me blocks it. I've had a good run with the Veil this autumn/winter, despite the frequently horrendous weather. 

Although the ES 25mm 100deg gets pretty bad reviews, I'd still like to have one just for the Veil and other big extended targets (nothing else that big springs to mind except Barnard's Loop!)  if one falls in my lap for the right price.  

Sat & Sun night looking good here, but my van is in for repairs so no carting the big dob around. 300p it is then this weekend!

I want to keep it simple though, it takes a lot of time to sort the checklist, load, unload, set-up, use, swap eyepieces/filters etc, take-down, load car, drive home, unload car...🤣

Really need to contact a big estate owner here and find a good, dark home for the 500p. I'd be willing to pay an annual storage/access fee, like a mooring fee for a (small) boat!

[PeterW]

Two eyes is a bad place to go…. Costs rise rather faster and availability drops with aperture. You’d need to fix the two optical systems very securely and then fiddle some way to adjust the IPD…. there are some good designs and plans online, but you’d be beating quite a rarely trodden path. 

I was cruising around northern Cygnus with my 70mm APM, pleasant even with the bad light pollution, need to get them under better skies…. the old aperture fever keeps suggesting that bigger bins would be better…

 

How did you get on with the actual large binoculars, be interesting to compare views with similar exit pupils (just an image scale difference). At least these are available upto 120ish mm, beyond that you are on your own!

 

Peter

[Ships and Stars]

3 hours ago, PeterW said:

Two eyes is a bad place to go…. Costs rise rather faster and availability drops with aperture. You’d need to fix the two optical systems very securely and then fiddle some way to adjust the IPD…. there are some good designs and plans online, but you’d be beating quite a rarely trodden path. 

I was cruising around northern Cygnus with my 70mm APM, pleasant even with the bad light pollution, need to get them under better skies…. the old aperture fever keeps suggesting that bigger bins would be better…

 

How did you get on with the actual large binoculars, be interesting to compare views with similar exit pupils (just an image scale difference). At least these are available upto 120ish mm, beyond that you are on your own!

 

Peter

Hi Peter, yes a big binoscope or 'binodob' sounds great but would require some precision engineering and knowledge. Arie Otte seems to have largely sussed it, though I don't know if he's still making them, and Mel Bartels is currently working on a rather insane 30" f2.8 binoscope which may or may not work according to him (if not, he'll simply turn them into two 30" dobs).

I still haven't properly got stuck in with the 20/40x100s yet, I need to calculate exit pupil, but don't know how as I don't know focal length or eyepiece mm, just magnification...

I'm hoping this weekend I can use them some more, need to rig a temporary altitude brake, or just use some threaded bar and wingnut to lock it and make fine adjustments to track when on target. 

Was that you that said they built a binoscope? I think someone on SGL has. For refractors, the EMS Matsumoto 'kits' look incredible, but not cheap. I'd thought about a couple of big cheap 150mm achros, but the EMS adapters are some serious money. A Swiss company makes the mounting platform though. Not AYO, is it?

Anyway, need to give the Quantum 5.1s a good workout this weekend! I was momentarily tempted to max the credit card on some APM 120mm EDs, but reality quickly came to the rescue...

Edited November 20, 2020 by Ships and Stars

[scarp15]

20 minutes ago, Ships and Stars said:

Was that you that said they built a binoscope? I think someone on SGL has. For refractors, the EMS Matsumoto 'kits' look incredible, but not cheap. I'd thought about a couple of big cheap 150mm achros, but the EMS adapters are some serious money. A Swiss company makes the mounting platform though. Not AYO, is it?

Anyway, need to give the Quantum 5.1s a good workout this weekend! I was momentarily tempted to max the credit card on some APM 120mm EDs, but reality quickly came to the rescue...

I think that Peter Drew has crafted one. 

[Whistlin Bob]

Very nice report- I too am going to miss the Veil, lots of great views this year, the season for it is really six months long with in Oiii filter for the Twilight nights.

I'm quite envious of your ability with the SW to move to a BV position- my 14" truss model doesn't allow this and so I need to Barlow my binoviewers to get a view, meaning they're for small targets only. But I do agree that although the view is a little dimmer, when they're dialed in properly it's a fabulous experience. 

[John]

1 hour ago, scarp15 said:

I think that Peter Drew has crafted one. 

This is a Peter Drew creation. These are 150mm each I think.

[PeterW]

The Exit pupil is just the aperture/mag  so your quantum’s are 5 or 2.5mm

http://www.aokswiss.ch are the Swiss bino makers.

 I’ve looked through a friends EMS,  very nice and easy to use and merge between users, didn’t think they were that costly?

120mm bins very popular, there is a “bargain” semi apo version.

http://www.deep-sky.co.uk/telescopemaking.htm have made several sheet metal binoculars over the years. The late Bruce sayre had some plans for a very nice single arm system.

 

PEter drew has made loads in the past, but no plans for new ones as I understand.

Noctutec seem to do one of you ask, details here https://www.noctutec.com/astronomie-shop/teleskope-noctutec/someone on cloudynights has one. The web probably has more homebrew ones, so get out the welding rig and plywood….. good luck.

 

 

 

Cheers

 

Peter 

[Ships and Stars]

10 hours ago, Whistlin Bob said:

Very nice report- I too am going to miss the Veil, lots of great views this year, the season for it is really six months long with in Oiii filter for the Twilight nights.

I'm quite envious of your ability with the SW to move to a BV position- my 14" truss model doesn't allow this and so I need to Barlow my binoviewers to get a view, meaning they're for small targets only. But I do agree that although the view is a little dimmer, when they're dialed in properly it's a fabulous experience. 

Yes the Veil is early evening at the moment, then dropping quickly. You might be able to make a second set of shorter truss rods - a bit of faff, but possible! I'm heading back out tonight, the Cocoon is top of my binoviewer challenge list

1 hour ago, PeterW said:

The Exit pupil is just the aperture/mag  so your quantum’s are 5 or 2.5mm

http://www.aokswiss.ch are the Swiss bino makers.

 I’ve looked through a friends EMS,  very nice and easy to use and merge between users, didn’t think they were that costly?

120mm bins very popular, there is a “bargain” semi apo version.

http://www.deep-sky.co.uk/telescopemaking.htm have made several sheet metal binoculars over the years. The late Bruce sayre had some plans for a very nice single arm system.

PEter drew has made loads in the past, but no plans for new ones as I understand.

Noctutec seem to do one of you ask, details here https://www.noctutec.com/astronomie-shop/teleskope-noctutec/someone on cloudynights has one. The web probably has more homebrew ones, so get out the welding rig and plywood….. good luck.

 

Thank you Peter! Looks like 20x is the way to go but will try 40x. I just made DIY filter threads for both sets of eyepieces and they look and work ok actually.

I will definitely have a close look at the rest. The EMS are works of art! Maybe not that expensive, all things considered. I tend to drift towards the top end stuff, so perhaps that's why they seemed pricey.

Noctutec is a new one to me - shall have a look now.

Good stuff! Thanks again.

[PeterW]

My friend needed to get his EMS slightly customised, very fast and professional response and turnaround from Mr Matsumoto. Be interesting to hear how your adventure continues...

peter