Binoviewers - taking the plunge...

[davesellars]

Well, last night I managed a very short window of opportunity to take a look at the Moon with the new configuration - 25mm plossls and the new barlow lens. I'd also measured my IPD (63mm) and pre-adjusted the bins to the same. This config gives 86x with the 4" refractor. I have to say wow... that was quite an impressive view even at this low - medium power.

18mm (BCOs) gets me to 119x while a 15mm eyepiece gets me to probably a more useful(?) 143x ... I'm at a quandary. I'm at a quandary because the BCOs are obviously top notch optically, but finding a 15mm EP with similar optical quality seems either impossible or have to go to Televue Plossl level and a slightly ridiculous price (these days), and certainly can't budget for... My concern with cheaper EPs is the level of contrast perhaps lost over the BCOs and more-so scatter/glare.

[Bigzmey]

Well, last night I managed a very short window of opportunity to take a look at the Moon with the new configuration - 25mm plossls and the new barlow lens. I'd also measured my IPD (63mm) and pre-adjusted the bins to the same. This config gives 86x with the 4" refractor. I have to say wow... that was quite an impressive view even at this low - medium power.

18mm (BCOs) gets me to 119x while a 15mm eyepiece gets me to probably a more useful(?) 143x ... I'm at a quandary. I'm at a quandary because the BCOs are obviously top notch optically, but finding a 15mm EP with similar optical quality seems either impossible or have to go to Televue Plossl level and a slightly ridiculous price (these days), and certainly can't budget for... My concern with cheaper EPs is the level of contrast perhaps lost over the BCOs and more-so scatter/glare.

This is a valid concern. Observing Moon, Sun, planets is all about sharpness and contrast and lack of those becomes even more evident at high powers. At one point I did a shootout between 15mm Plossls, and your typical Meade/Orion/Celestron Plossls do loose in sharpens and contrast to TV. BCOs is a whole different story. They are top performers.

I would take 18mm BCO over 15mm none-TV Plossl any time.

[davesellars]

I would take 18mm BCO over 15mm none-TV Plossl any time.

Many thanks Andrey. I think that's my conclusion as well... Just have to convince the CFO of the house.. lol

[Bigzmey]

I would take 18mm BCO over 15mm none-TV Plossl any time.

Many thanks Andrey. I think that's my conclusion as well... Just have to convince the CFO of the house.. lol

Do what you have to.

How is used astro market in UK? Once my better half saw that I can sell astro stuff with ease, all approval process became much easier.

[davesellars]

Used market is generally pretty good... No BCOs though and I've only rarely seen 18mm ones come up...

[davesellars]

OK, so success... Two 18mm BCOs purchased along with an extension to cloudy conditions... :p

[Bigzmey]

OK, so success... Two 18mm BCOs purchased along with an extension to cloudy conditions... :p

Congrats!

[davesellars]

BCOs arrive tomorrow and apparently a break in the clouds / rain! Fingers crossed for an early morning session although the Moon may be a bit low.

[Bigzmey]

BCOs arrive tomorrow and apparently a break in the clouds / rain! Fingers crossed for an early morning session although the Moon may be a bit low.

Screenshot 2022-08-18 at 20-39-19 Clear Outside v1.0 - International Weather Forecasts For Astronomers.png

You have managed to break the clouds curse, what is your secret?

[davesellars]

Not sure about that... clouds rolled in 10 mins after they arrived this morning! Looking good though and hopefully it will clear sufficiently tonight to get a good look at Jupiter which will be well positioned at 1am with the GRS.

[davesellars]

Lovely clear night... 102ED with the binoviewers and the 18mm BCOs on Saturn so far. Very comfortable to use! Seeing not great but some nice detail coming and despite only 119x seems more. Awesome to see detail without having to strain just the one eye. Waiting now for Jupiter to rise sufficiently...

[davesellars]

Oh wow... Jupiter was absolutely brilliant in the binoviewers. The GRS was very clear with detail around it and depth to the storm with nice orange hue and a mountain of detail within the belts themselves. Probably the best I've seen the planet yet. I didn't feel like more magnification was actually required.

[Bigzmey]

That's great! I have observed Jupiter a few times this season but have not caught it on a night with good seeing.

[davesellars]

Last night after coming in from a short session with the binoviewers viewing Saturn and Jupiter (lots of good detail yet again!) I removed the 2" adapter attached to BV nose and the nose promptly came off with it... I knew the connection was on by perhaps a thread or two and looked to be stuck as you can see from this image earlier...

bins4.jpg (15.86 KiB) Viewed 1147 times

Fortune had been on my side at least that the bins had not separated from the nose while in use! Anyway, the threads look pretty bad and crossed in one area as well. The nose would not fit back on strongly and even when it did it was clearly off-centre. So I set about cleaning up the threads with a fine sharp edge and then filing down a little the first thread of the nose piece. Together with a very light touch of lube seemed to do the trick and now the nose fully threads on (and importantly off again...) Although some metal dust went in the BV on the glass I managed to clean up the detritus and then cleaned it properly with some Baader fluid. Perhaps a quick test later for some solar as the sun is out!

[Bigzmey]

Wow, close call! Hopefully, no long lasting consequences. I will keep an eye on mine since it is very similar design.

[davesellars]

Shouldn't be any issue as long as the nose is properly screwed in - mine wasn't from arrival and wouldn't screw in any further (but seemed strong enough at the time...)

I opened up the BV covers as well to dust off the prisms with a blower as some of the metallic dust had settled on them further down. All seems to be clear now and waiting for a chance to try them out...

I've found a possibility of higher power with some Pentax XF 8.5mm which are at a much discounted price... thinking these with the 2x barlow that comes with the BV may suit... Need to check again the focus with the 1.25" mirror diagonal with the 4" frac.

[Bigzmey]

I've found a possibility of higher power with some Pentax XF 8.5mm which are at a much discounted price... thinking these with the 2x barlow that comes with the BV may suit... Need to check again the focus with the 1.25" mirror diagonal with the 4" frac.

If you can get XF 8.5mm at a good price. Go for it. Those are very nice EPs. They may work with 3x barlow to.

[davesellars]

Apparently out of stock (so much for their website being up to date!) :p Thought it was too good to be true (£78 instead of £179) .. oh well.

[Bigzmey]

Apparently out of stock (so much for their website being up to date!) :p Thought it was too good to be true (£78 instead of £179) .. oh well.

I had 8.5mm and 12mm XFs for a while. Good quality EPs and fit nicely between XWs (I wonder if it was done on purpose). When I got BV last year I was looking for another XF set to make pairs. They were out of stock but I managed to pick both of CN/AM classifieds by posting wanted add. I even got some offers from Europe, but the shipping was pricy, so with a bit more waiting I managed to find US options. Give it a shot, posting add is free.

[davesellars]

OK, so all good with the BVs and seem absolutely fine and sharp view after doing a good solar session with them.

I think I'll go back to looking out for 12 - 13mm. At the moment I think the 12.5mm orthos are probably the best bet for fit as well as the light weight and certainly for critical planetary observation I guess you can't get any better...