Coma Focuser for LS50

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Coma Focuser for LS50

Post by _RA_ »

I searched, and couldn't find any references here, so asking...

Does anyone have one of these, or have direct experience with one of these:

https://www.adrianololli.com/articolo.asp?ID=4140

?

Curious to know if it's a worthy upgrade to the Lunt stock helical (low bar, I know... ) and a viable alternative to the much pricier options.

Thanks!

~ RA

[I debated about asking in this forum vs "Commercial Solar Filters/Cameras/Hardware," but since this isn't exactly "standard" gear, I thought I'd go with here. Mods please feel free to move if appropriate.]


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Re: Coma Focuser for LS50

Post by marktownley »

First i;ve seen or heard of it, looks interesting!


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Re: Coma Focuser for LS50

Post by _RA_ »

Those YouTube videos go back to late 2016, so it's been out for a while. Market penetration seems modest, at best... No evidence of it here, and the only mention I've seen so far over on CN is a user who was able to borrow one, but not (yet) give a thorough review.

For tighter, smoother action and the promise of even a few more millimeters of back-focus, it'd be worth it to me, even with shipping to the States.


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Re: Coma Focuser for LS50

Post by marktownley »

I'm in the process of replacing the focuser on my LS50 too...


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Re: Coma Focuser for LS50

Post by _RA_ »

marktownley wrote: Sat Feb 26, 2022 5:30 am I'm in the process of replacing the focuser on my LS50 too...
Ah, interesting... standard upgrade, or something more custom?

I haven't reached out yet to the guy in Italy to see what a return policy would be. I really want to support efforts like that, but I do have to minimize my gear gambles.

Keep us posted!

~ RA


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Re: Coma Focuser for LS50

Post by marktownley »

Nothing too exciting. The original helical was broken, i've had the moonlite and feathertouch on it. I think I will rejuvenate the scope again this solar cycle. I have an adapter on order that will give me a t2 connection which I can attach to a helical I have lying around.

Mark


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Re: Coma Focuser for LS50

Post by vkx86 »

FYI, that focuser mentioned in that post on CN:
https://www.cloudynights.com/topic/8091 ... r-lunt-50/
with some details.


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Re: Coma Focuser for LS50

Post by _RA_ »

vkx86 wrote: Sun Feb 27, 2022 8:30 pm FYI, that focuser mentioned in that post on CN:
https://www.cloudynights.com/topic/8091 ... r-lunt-50/
with some details.
Indeed, and that's me in the second post asking for updates, about a month ago.
Hopefully there'll be some new news soon.

~ RA


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Re: Coma Focuser for LS50

Post by brendant »

As an update for anyone checking this thread I recently noticed these focusers are back in stock (May 2022) and can be ordered direct from Adriano Lolli in Italy. Ordered one and it was delivered within two weeks to the UK, direct replacement and is superb in comparison to the original Lunt focuser.

https://www.adrianololli.com/articolo.asp?ID=6117


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Re: Coma Focuser for LS50

Post by _RA_ »

I finally decided to purchase one of these, and I actually received it several weeks ago... perversely a day before travel. I immediately confirmed the fit with the LS50, but had no time for observation until I returned, and even then, first light was hasty and through cloud holes.

Yesterday I had both clear skies and time, with tolerable seeing. Here are my impressions:

My main goals for the upgrade were affordability, extended focus travel, and smoother, friendlier operation.

As for the latter, it is a huge improvement over the stock helical focuser. It is not "read-your-mind" smooth, but it is an enormous relief after wrestling with the native version.

For back-focus, I was really hoping to extend range with my Arcturus binoviewers and their included 30mm EPs. My next step in my collection is a Meade 4000 26mm, and I can't seem to bring that to focus, so no joy there. The 26mm seemed close enough that a 28mm might work, but I don't own one.

For single ocular mono-viewing, I'm good down to my TMB 5mm, currently the highest power I own. I have not yet tested with Barlows.

In terms of value, I'm really very pleased. I had some difficulty in navigating their web site and placing the order and followup communication, but I'm sure some of that was user error and working across language barriers. I understand it's a small operation, and that this is an artisanal item in an already extremely niche market.

My biggest complaint is the lack of any graduation index. Having markings to show where you are in your focuser travel is nice, allowing you to return to a known position quickly, and assess the relative distance between oculars. It's a small thing, but being such, it seems like it would have been a simple feature to add. It's the only area where the Lunt stock helical actually has the advantage. Presumably I could add my own, but I shouldn't have to.

Notwithstanding, I'm a satisfied customer. I paid a price that I consider fair, and that allowed me to go ahead and pay for the shipping insurance for extra peace of mind. The premium focusers that are available for this scope are out of my reach, and I'm very grateful that someone saw the need and was able to fill the gap.

I hope they sell more, and thrive.

~ RA


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Re: Coma Focuser for LS50

Post by LostInSpace »

_RA_, any followup comments regarding the Coma helical focuser? Thanks for info. The Adriano Lolli focuser at least as of yesterday was listed on Sale for 95Euros, ~$104usd. Lunt 50mm is in transit from the vendor. After maybe too much reading and YTube viewing about the issues with the stock helical and the possible design flaws. Purchased the Coma Lolli unit. The feather touch was a bit too steep for my entry into solar viewing. Just a visual observer.

Lunt manufactures the helical in-house. Maybe one of these days they will update the unit. Maybe license the right to manufacture the Coma focuser for North American distribution and sales. Lots of maybes.....


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Re: Coma Focuser for LS50

Post by LostInSpace »

Can this focuser handle the additional weight of a binoviewer?


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Re: Coma Focuser for LS50

Post by Rusted »

Can a lack of back focus be fixed with longer, but parfocal, eyepieces? Probably not.


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Re: Coma Focuser for LS50

Post by marktownley »

Using a barlow before the ep/camera will increase the effective focal length which would work well with longer focal length eyepieces.


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Re: Coma Focuser for LS50

Post by _RA_ »

@ LostInSpace:

No real followup, except to say that I continue to be very pleased with it. It's much smoother than the stock helical, and just has an overall better feel. I still miss having registration marks when changing EPs, but it's not like I can't find focus without them.

I haven't had any out-of-the-ordinary trouble with my binoviewers. As always, they need extra attention to being secure, and as always, they might unscrew the diagonal barrel if balanced on the counter-clockwise side, but that's just the nature of the beast and nothing to do with this focuser.

Balancing this little scope on the mount has always been a minor issue for me. It's a little tail-heavy to begin with, but adding binos only make it worse. Again, not much to do with the focuser. I may replace the stock dovetail with a longer one at some point.

My main reason to upgrade was in the hopes of gaining a little in-focus for binoviewing. I'm using an Arcturus brand with its stock 1.85x Barlow on the nose, and twin (included) 30mm EPs. I have no problem with focus with this setup on either the stock Lunt or the Lolli. Unfortunately, I have gaps in my EP collection that currently prohibit stepping down <30mm to see what works, so the jury's still out there.

I've read that there is a way to attach the Arcturus binos directly to the diagonal/blocking filter housing, bypassing the barrel completely. This would result in a significant gain in back-focus liberty, but I haven't learned yet exactly what adapter combination is necessary. Input on this would be most welcome.

That said, even if I can't eek out a little more magnification in the binos, I don't regret the Lolli upgrade.

As for mono-viewing, I get great views with my AstroTech UWA 10 & 7, and have also had good results with a range of TMB planetary clones, depending on seeing.

Hope this is helpful.

~ RA


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Re: Coma Focuser for LS50

Post by LostInSpace »

Thanks RA. Useful info. Considering using a binoviewer and a pair of the Lunt zooms if I like them. Spec note 5.5oz (156gm). Seems light for a zoom. Considering the Kasai Linear style binoviewer marketed by a handful of companies. Assuming the Orion, Lang Perng, Lunt, ES... are just cosmetic clones. Heavier and bit more expensive than the Arcturus, but supposedly no back on in focus issues on the Lunt and other refractors and even Newts.

OT: Awesome AM session. Newbie. 1st Dispartion Brusque prom viewed. Made up for the clouds that came in last night and obscured the Northern Lights.


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Re: Coma Focuser for LS50

Post by _RA_ »

I haven't been able to get my Lunt zoom to work with these binos. Not sure if even at 21mm it would reach, but I hope to find out what's possible if I can learn more about shortening the light path by eliminating the blocking filter barrel as mentioned above.

I really love the bino view, but with my setup it's strictly for low-power full-disk views. For more detail when seeing allows, I do like more magnification. Also, a single EP is just easier for short sessions.

Congrats on the sighting. And yeah, alas... we were socked in here in CenTex also.

~ RA


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Re: Coma Focuser for LS50

Post by LostInSpace »

Thanks. Decided if going bino will probably go with the Kasai Linear style. Read a review by a Great Britain user. Preferred his William Optic except for use on his Lunt 50 or 60. Why he kept the Kasai Linear style.

New the Lunt Helical was very functional. Then one day I thought the focuser had come loose from the OT. Nope. The wobble. I now have to brace the focuser against one end of the wobble, focus, lock down. Still wobbles and goes off focus a bit if I touch the EP or block filter and nudge it to the opposite side. Real pita when using the junky zoom. Now I understand more clearly Lolli's YTube video explanation of the design flaw in the Lunt Helical.


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Re: Coma Focuser for LS50

Post by LostInSpace »

Focuser has been shipped:). Cloudy, rain, cold since yesterday. Good time to search for as much info possible about the Lunt Helical. Thread on CNs noted the one screw that is exposed when focused to max length may loosen. Checked. Screw/bolt is tight. Under the rubber grip are some grub screws or regular screws that may loosen. Next thing to check after the Coma arrives. But based on Lolli's YTube it is probably the design issue that eventually causes wear with use and the slop.

I liked the fine focusing ability of the Lunt Helical before slop set in. Hopefully the fine adjustment is similar in the Lolli. Bit of a bummer that the Lunt FeatherTouch is a single speed. Starlight has a dual speed upgrade. Adds another $200.


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