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Trouble getting camera focus with a Lunt ls50 single stack

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#1 telradrigel

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Posted 25 April 2015 - 04:02 PM

Hi,

 

Last year I went to NEAF and did some solar viewing for the fist time. Needless to say, I have been dreaming about the views since. this year I saved up my sheckles and when NEAF rolled around, I knew i had to get a solar scope. I went strait to the Lunt booth and looked at their lineup. I liked the fact that they are made here in the U.S. What really sold me was the pressure tuner. I settled on the 50mm due to price and was please to find that Lunt knew a vendor had them in stock at the show. When I got the scope home, the views were amazing! Just like at the solar party, just like te images stuck in my head all year long. 

 

I have to say the images I have seen on this forum are incredible. This is my first foray into solar imaging. But there is one problem, I cannot get either my zwo as120mc or my dale canon rebel sx to focus! I have attached them both just on the eyepiece side of the b600 by unscrewing the ep holder and screwing both directly on the b600 using just the adapter for the canon and removing the 1.25" barrel on the zwo.  I just doesn't come I on focus. What am I doing wrong?

 

Anybody have any suggestions?



#2 CosmicWreckingBall

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Posted 25 April 2015 - 04:56 PM

Sounds like you need more back focus for sure. 

 

Did your ZWO come with an M42 -1.25 adapter?  That's what i did with my ZWO and my DSLR. The supplied 1.25-M42 adapter worked in both cases. 

 

Heres oes a link to one: https://www.astrofac...ce-adapter.html

 

You'll have to double check your thread size to ensure it is indeed an m42 thread on your camera. 


Edited by StarFood, 25 April 2015 - 05:11 PM.


#3 saguaro

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Posted 26 April 2015 - 12:22 AM

For the ZWO camera try this: screw it directly into the B600 diagonal (eyepiece side) just as you described, then back the diagonal out of the tube a little (about an inch) and that should allow you to get focus. This is how Teale Britstra was able to focus his ZWO and Lunt50 http://www.brightsta...om/first-light/



#4 Martin Hoyle

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Posted 26 April 2015 - 01:26 AM

I wondered What A http://www.zwoptical...SI120/index.asp zwo as120mc was!

 

Now I Know!

 

Martin



#5 telradrigel

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Posted 26 April 2015 - 09:13 AM

Hi guys,

I used both the 1.25" adapter and screwed it directly into the b600. Both methods didn't seem to work. I could not get a fine edge on the solar disk. I tried moving the focused as far in as possible and it started to get more defined but then it stopped. Maybe my focuser is not letting me bring the sun to a crisp disk.

I think it's the focuser because I can not get it down past the 4 mark. I just unscrewed it off the filter and now it will go all unscrewed it off the filter and now it will go all the way down to zero.
I guess I have to call one now and get a replacement focus or or space or ring so that the back of the focus or doesn't scrape on the filter.

#6 telradrigel

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Posted 26 April 2015 - 10:03 AM

Before making my call to Lunt, I decided to test my theory. I made a simple washer out of a plastic blister pack package. The dimensions to fit in the filter were 1.4" diameter with a 1" hole. I used my epilog laser to cut it out but I'm sure I could have used scissors and a knife. (What's the point of having cool toys if you don't use them?😀)
The washer fit perfectly in the filter with the screws threads holding it in place and centered. Now the focuser is able to be turned to 0.

The focuser also felt like it was scraping something internally as well. I noticed a screw on the side of the focuser that had its anodizing worn off around the edges. Sure enough, I tightened it down and now the focuser is as smooth as silk.

So far the Lunt 50 has some enormously georgeous views but is sadly crippled by the quirky and flawed focuser. I wonder how many other people have encountered the same problems?

I will still follow up with Lunt and ask for a replacement. They need to know flaws with their products before they make a negative name for their product in this small of a market.

#7 saguaro

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Posted 26 April 2015 - 10:05 AM

Hi guys,

I used both the 1.25" adapter and screwed it directly into the b600. Both methods didn't seem to work. I could not get a fine edge on the solar disk. I tried moving the focused as far in as possible and it started to get more defined but then it stopped. Maybe my focuser is not letting me bring the sun to a crisp disk.

I think it's the focuser because I can not get it down past the 4 mark. I just unscrewed it off the filter and now it will go all unscrewed it off the filter and now it will go all the way down to zero.
I guess I have to call one now and get a replacement focus or or space or ring so that the back of the focus or doesn't scrape on the filter.

 

I have the same scope (but a different camera; Skyris 132m). However, I know of several folks with the LS50/ZWO camera that you have who have been able to achieve focus and get good full disk shots. For example, here is a post on Solarchat that has a photo of the ZWO mounted on the Lunt50: http://solarchat.nat...cfbcc4d44dee814

 

If you scroll down in this post, you'll see a photo of the ZWO mounted to the Lunt50 blocking diagonal. It looks like Gordon used a 10mm T-thread spacer tube between the ZWO and the blocking filter, and then he backed the diagonal out of the focuser tube a little bit to get focus. I suppose if you knew the exact spacing you could get a T-thread spacer ring that would allow you to get the correct spacing with the camera so that you wouldn't have to back the diagonal out of the focuser at all. Perhaps a 15mm T-thread spacer is all you need. Hope this helps.

 

I see that you have the color version of this camera. A mono camera will provide you with much better resolution; my understanding is that you lose alot of resolution with the color chip. Perhaps that's why you are having trouble detecting when you are in focus.


Edited by saguaro, 26 April 2015 - 11:23 AM.


#8 saguaro

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Posted 26 April 2015 - 10:11 AM

Before making my call to Lunt, I decided to test my theory. I made a simple washer out of a plastic blister pack package. The dimensions to fit in the filter were 1.4" diameter with a 1" hole. I used my epilog laser to cut it out but I'm sure I could have used scissors and a knife. (What's the point of having cool toys if you don't use them?)
The washer fit perfectly in the filter with the screws threads holding it in place and centered. Now the focuser is able to be turned to 0.

The focuser also felt like it was scraping something internally as well. I noticed a screw on the side of the focuser that had its anodizing worn off around the edges. Sure enough, I tightened it down and now the focuser is as smooth as silk.

So far the Lunt 50 has some enormously georgeous views but is sadly crippled by the quirky and flawed focuser. I wonder how many other people have encountered the same problems?

I will still follow up with Lunt and ask for a replacement. They need to know flaws with their products before they make a negative name for their product in this small of a market.

I totally agree with you about the focuser. It is the only negative thing in an otherwise wonderful scope. In fact, I hated the poor focuser so much that I have replaced it. Before doing so, I did contact Lunt and described my issues with the focuser, and they told me it was "normal' behavior. You should definitely complain about it to them, since the feedback from customers may encourage them to find a better focuser to supply with the scope.

 

Here is the thread I wrote on my Lunt50 focuser upgrade: http://www.cloudynig...-h-alpha-scope/

 

But we shouldn't have to replace it; Lunt should really supply a better one!



#9 saguaro

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Posted 28 April 2015 - 09:14 AM

Telradrigel,

 

Any luck getting your ZWO camera to focus? Also, did you contact Lunt about your focuser issues? Thanks.



#10 nickatnight

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Posted 28 April 2015 - 12:54 PM

I have a ZWO camera on the way, and am anxiously awaiting news on connecting it to my LS50. I have a shortage of adapters so I'm assuming I'll have to order something. Please post your solutions when you can. Thanks!

#11 saguaro

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Posted 28 April 2015 - 01:24 PM

Nickatnight, did you order a mono or color camera? Mono is best for solar. Which ZWO did you order?

#12 nickatnight

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Posted 28 April 2015 - 02:22 PM

I ordered the ASI120MC-S, the color version. I do understand the sensor sensitivity difference. I want to get planetary imaging done with the same camera, and don't wish to mess around with filters and all. I'm on a bit of a simplification kick lately. If I find it unsatisfying, there's always a better camera out there. Maybe one to go with a bigger solar scope!

#13 nickatnight

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Posted 28 April 2015 - 10:39 PM

...and two hours later UPS came to visit. We'll see if I can get this thing rigged up tomorrow.

 

image.jpg



#14 nickatnight

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Posted 29 April 2015 - 01:34 PM

Focus achieved out of the box, but not ideally. After testing every configuration with supplied adapters, I found that I had to do a combination of backing the diagonal out of tube, and unscrewing the directly connected (eyepiece holder removed) camera to back it away from diagonal. I left just one thread turn for camera before falling off. Then had plenty of play with Lunt focuser. If I backed diagonal out too far with camera screwed all the way in, I could focus, but vignetting made it impossible to get even illumination on the disk. Once I found I could focus, I slowly worked the diagonal into the tube, tweaking focus along the way until it was far enough in the get even exposure.  I've captured 10 or so different full disk MOVs on my Mac, and need to process to see if what I got is any good. Hopefully have an image to show by tonight. Now I need to figure out the right adapters to achieve this without unscrewing and sliding everything out of whack.

 

image.jpg


Edited by nickatnight, 29 April 2015 - 01:36 PM.


#15 saguaro

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Posted 29 April 2015 - 04:09 PM

Focus achieved out of the box, but not ideally. After testing every configuration with supplied adapters, I found that I had to do a combination of backing the diagonal out of tube, and unscrewing the directly connected (eyepiece holder removed) camera to back it away from diagonal. I left just one thread turn for camera before falling off. Then had plenty of play with Lunt focuser. If I backed diagonal out too far with camera screwed all the way in, I could focus, but vignetting made it impossible to get even illumination on the disk. Once I found I could focus, I slowly worked the diagonal into the tube, tweaking focus along the way until it was far enough in the get even exposure.  I've captured 10 or so different full disk MOVs on my Mac, and need to process to see if what I got is any good. Hopefully have an image to show by tonight. Now I need to figure out the right adapters to achieve this without unscrewing and sliding everything out of whack.

 

attachicon.gifimage.jpg

Great! I'm guessing you will need about 15mm of spacing. Here is a set of T spacers that should provide enough combinations if you're not sure http://telescopeadapters.com/

(Scroll down to last item on that page.) Of course, if you know the exact spacing, you can just order what you need from Scopestuff, Agena, etc. But this is a good set if you are not sure of the exact spacing.



#16 nickatnight

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Posted 06 May 2015 - 02:33 AM

I've ordered one of these which is the closest match to what I think I need for spacing the camera back from the diagonal without having to leave it partially unscrewed. This will give me 12.57mm additional spacing

 

http://www.edmundopt...t-adapter/1316/

 

A little off topic on camera focus, but I also ordered the shorter eyepiece holder (15mm) on ebay, which I think will allow me to use my 2x barlow for visual. My 5x Powermate will focus, but not the 2x barlow. Best "power view" I've gotten is with the Meade 18mm Ultra Wide Angle eyepiece with the 5x Powermate, giving 3.5mm. The full disk was still in the Ultra-Wide eyepiece, although extending out into my periphery. Worked well in the morning, but less well once the heat of the day hit.



#17 telradrigel

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Posted 06 May 2015 - 11:22 AM

Interesting, with 12.57mm of space in back of the diagonal wouldn't the 1/4" adapter work or is that too much distance? I don't have the scope in front of me to check. 

 

After I fixed the focuser, I was able to get slightly better focus. 

 

Nick, I also use a mac. What capture software are you using and what are your camera settings too?

 

Here is a pict of my nice simple and compact setup. Everything except the tripod fits in a harbor freight pluck case.

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#18 nickatnight

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Posted 06 May 2015 - 10:02 PM

That's a nice looking setup. Very compact. How's the Cube work for you? If I want to track I need to piggyback on a beefy CPC925. I think that'll be tested this weekend.

 

You bring up a good point about the shorter 1/4" eyepiece holder. I may have solved the issue twice, once with a t-threaded direct camera connection, and one using the camera nose-piece. I had already ordered the T-Thread to C adapter for the camera, and then found the shorter eyepiece holder. All good parts for the toolkit in any case. I'll let you know how they work out. The mono ZWO ASI120MM-S came in the mail today, so I'll be shooting mono next time out. Actually, with two cameras, maybe a situation will come up for using both adapters.

 

When you mentioned fixing your focuser, I went back to reread this whole thread, and something stood out to me regarding my focuser wiggle. You mentioned a screw that you tightened, and I had examined the focus tube days ago and found no screws. I checked again today, and after screwing the focuser all the way, I found a screw was revealed! And it wiggled in tune with the focuser issue I was having. I took a few full turns to get the screw tightened back down, and about 85% of the wiggle was GONE! I think the remaining 15% would pass QC, so I'm holding off calling Lunt for a replacement. We'll see how it holds up after a little use. But thank you for your notes in this thread. They certainly came to some good.

 

We have a harbor Freight that opened in my town I've yet to visit. Think I'll take a look at their cases. Good tip.

 

As for Mac capturing, I used a free App called OACapture. It did an OK job, but I found out my PC Laptop has USB 3.0, and I really like the FireCapture App better, which is only available on the PC, I think. So I've started using my PC for capturing and processing. Things like that have been happening to my poor Mac lately. I haven't found any advantage to going Mac over PC for solar, lunar or planetary. The best Apps I found on the Mac are ported from the PC (RegiStax6 and AutoStakkert!). If anyone can change my opinion there, I'd love to put the Mac to good use.


Edited by nickatnight, 06 May 2015 - 10:03 PM.


#19 telradrigel

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Posted 06 May 2015 - 10:33 PM

Sadly I have been finding the same problem with my macs too. I have two hobbies, astronomy and cnc and laser woodworking, both have better/only programs for the PC. My cnc/laser work only uses pc programs and as a result I find I'm spending more time in windows than my Mac! Thank God for parallels! I use backyardEOS a lot for automating my long exposure astro photos.

 

On the solar front, the little ioptron smart star A mount works great for this little scope as long as it's not too windy. The tripod is the week link with this setup.  Thinking of working on a replacement using some old photographic ones I have laying around the shop.

 

btw.. here's my solar case

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#20 nickatnight

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Posted 06 May 2015 - 11:42 PM

The case looks great, and it's amazing to fit the mount in there too. Thought you were hiding a double stack unit off to the left of the pic, but then I recognized it as a ZWO camera.  :grin:



#21 telradrigel

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Posted 07 May 2015 - 09:38 PM

Double stack would be great. Just need to save up more coin.... But I think a c11 is my first priority now.



#22 nickatnight

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Posted 15 May 2015 - 11:02 PM

A little more news on focus issues. I took a chance and picked up a Meade 3x short focus Barlow to see if I could get it to work visually or for imaging with the LS50THa. Out of the box, it wouldn't focus, but by removing the eyepiece holder from the Barlow, I was able to drop it down in the blocking filter diagonal eyepiece holder. At that point I couldn't put an eyepiece in as the Barlow element was too tall, but I happened to have picked up a shorter eyepiece holder that could screw onto the stock eyepiece holder, and allowed the eyepiece to mount up against the Barlow. Yes, focus was easily achieved with multiple eyepieces, including the full range of the Lunt Zoom eyepiece. I had a giant prom in full detail, with a view I would say is good for studying a quarter of the disk. I believe this will work with the ZWO camera too; will try this weekend. I also picked up the 2x Barlow Saguaro has had luck with, but haven't tested yet. As the 2x drops to 1.5x when dropped in the diagonal eyepiece holder, I'd think the 3x should drop to around 2.25x, but that's just a guess. That would mean the Lunt Zoom eyepiece would give 50-110x mag with the 3x Barlow. Feel I can hold off on a bigger solar scope for a little while now. Here's the setup

with the doubled up eyepiece holder, with Barlow element shoved down diagonal ahead of eyepiece.

 

image.jpg


Edited by nickatnight, 15 May 2015 - 11:13 PM.



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