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Helical prominence, first sol with the lunt 50

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#1 wxcloud

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Posted 05 May 2021 - 06:34 PM

Okay, horrible image quality here, just held, well tried to anyway, the phone to the included zoom eyepiece. Looks like I missed focus and probably off band also and we'll, it's a cell phone image. I couldn't resist. Basically just tossed the single stack lunt on my tripod just to try it. Zoomed all the way out I could see an worm peaking out the limb of the sun, as I zoomed in closer and fiddled with focus and the tuner the worm morphed into a helical ribbon almost tornado.

 

Was fighting bad transparency and seeing, non tracking mount and trying to find my way around things. 

 

Unfortunately I couldn't get a decent image. I did notice the orange glow around the eyepiece also presented in the image. Didn't see surface granulation or anything but the prominence was a real treat for first sol shocked.gif smile.gif it almost looked 3d.

 

I did try my wo binoviewers but no luck frown.gif

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#2 astro rocketeer

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Posted 05 May 2021 - 06:47 PM

Congrats on first light! Just like looking into an eyepiece. Thanks for sharing 


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#3 chemman

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Posted 05 May 2021 - 11:52 PM

Hey that is not to bad at all.  

 

My first day I think I borrowed two left arms from a blind person, no idea what I saw that day.  And you have a picture to boot!

 

Chuck


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#4 wxcloud

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Posted 06 May 2021 - 11:25 AM

I still don't have much of a clue how the tuner works so I didn't fiddle with it much. Surprisingly the whole disc fit into max zoom on the eyepiece... Still wanted to get closer. I tried the 3mm delite and couldn't seem to get focus, could have been too much eyepiece or just misplaced the sun and got the reflection.

Really want to try some actual imaging

#5 GOLGO13

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Posted 06 May 2021 - 11:37 AM

I suggest turning the pressure tuner all the way in, then back it off until the details on the sun look best. For me I don't have to go very far before it works best.

 

The Lunt 50 appears to have very limited inward focus (backfocus I think they call it). So a few of my eyepieces didn't work. That being said, A Delite should probably be OK. But 3mm is pretty high power and maybe that's more the issue.


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#6 BinoGuy

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Posted 06 May 2021 - 04:04 PM

I have the Lunt 50 with the branded zoom.  The lower end is 7.2mm I believe, and with the B600 blocking filter the full disk fits quite nicely, with a few mm of black space on each edge.  I doubt even a 5mm would fit the full disk and I'd be surprised if there is enough backfocus.

 

Nice shot! 
 

 

Clear Skies  BG  °¿°


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#7 wxcloud

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Posted 06 May 2021 - 11:27 PM

By "all the way in", do you mean with the tuner in my left hand, thumb on top to rotate the tuner thumb towards the sun, or away? Still trying to learn this thing :)

//

Is the televue solar finder worth having? I mean it took a little bit to find the sun without it, just used shadows to get me in the general area.

As far as getting closer I do have a couple cheapo meade barlows, would actually like to upgrade to a powermate but those don't exist right now lol. If I shove my asi290mm mini in, should get me pretty up close I think, if it will focus that is. Have an idea to use a parfocal ring on it to get close focus then scope focuser for fine tuning. Trying to figure out a way to omit a laptop for imaging and just try a raspberry pi with firecapture and my phone to control it. Not sure if that's possible.

#8 alvacouch

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Posted 07 May 2021 - 05:34 AM

Congrats on the first shot! I am also greatly enjoying a Lunt 50. 

 

I have always had trouble with pressure tuning. When proms are available, I tune for best proms. When they are not available, I tune for surface detail. Guidance on tuning I have received from here -- while excellent for tilt tuning -- is difficult to apply to pressure tuning. 

 

One thing with the Lunt 50 is that you can often see a lot more of what's going on by simply centering different parts of the sun in the view. Remember that the sweet spot in tuning for a pressure tuner is in the center of the view. So I've gotten in the habit of moving the view around to get more prominence detail, and when I find a prominence, centering it and then retuning often proves optimal. 

 

Limited focus travel has always been a problem with the Lunt 50. I've converted mine for the Starlight instruments focuser upgrade but limited in-focus is still a problem. I've segregated my eyepieces into "works" and "doesn't work" groups. All the TeleVue plossls and my two TeleVue Naglers (4.8 and 7mm) work fine. The Celestron 7-21mm works. Others do not fare as well. One huge surprise is that my reticle eyepieces all fail to come into focus. 



#9 rigel123

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Posted 07 May 2021 - 05:48 AM

By "all the way in", do you mean with the tuner in my left hand, thumb on top to rotate the tuner thumb towards the sun, or away? Still trying to learn this thing smile.gif

//

Is the televue solar finder worth having? I mean it took a little bit to find the sun without it, just used shadows to get me in the general area.


What you describe about the tuner sounds like you are talking about a tilt tuner wheel. Is your scope a pressure tuned model or a tilt tune? If it is a small wheel on the tuner then it is a tilt tune. In that case rotate the wheel all the way to the right to start out with. Don’t force it but you should feel some resistance. Then while watching through the eyepiece rotate the wheel to the left until you start to see some texture show up on the disk. Keep rotating the wheel to the left until the texture starts to disappear again and then rotate the wheel back to the right to get the full disk showing texture all across the disk and you are good to go.

As to the finder, yes, any solar finder is worth it to make finding the sun quickly.

#10 wxcloud

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Posted 07 May 2021 - 08:26 AM

It's pressure. It's a large black cylinder hanging off to the side. I just used my thumb as example of how I interact with it.

The double stack module is tilt however as it has the tiny brass gear off to the side. Haven't double stacked yet.

#11 rigel123

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Posted 07 May 2021 - 09:17 AM

It's pressure. It's a large black cylinder hanging off to the side. I just used my thumb as example of how I interact with it.

The double stack module is tilt however as it has the tiny brass gear off to the side. Haven't double stacked yet.

I would suggest you start by downloading the manual for your scope if you haven't already, here:

 

https://luntsolarsystems.com/manuals/

 

And also download the manual on the DS unit from this page as well.  It has pretty straight forward instructions.



#12 wxcloud

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Posted 07 May 2021 - 11:45 AM

Just had a very quick outing. It's getting warm outside. Tossed the rig onto the shaky star adventurer, found the sun very quickly, set tracking to solar didn't see much. Did find the new sunspot emerging on the limb. Fiddled with focus and tuning and couldn't find any proms. Figured I'd test out the (trash) afocal phone holder to see if that would allow quick images. It didn't. Whole set up seemed worse.

For some reason stationary tripod seemed to keep things in eyepiece better first outing. I don't think the thing was tracking at all or I bumped it bad trying to get phone attached to eyepiece.

4.8 nagler didn't seem to want to focus either.

#13 jwestervelt

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Posted 07 May 2021 - 12:52 PM

It's pressure. It's a large black cylinder hanging off to the side. I just used my thumb as example of how I interact with it.

The double stack module is tilt however as it has the tiny brass gear off to the side. Haven't double stacked yet.

"all the way in" means just that.  When you turn the pressure tuner, the large black cap will either move inward towards the scope, or outwards away from it.  When you tighten it inward, less of the brass threads will be visible.  It will become increasingly difficult to turn as you bring it in, and eventually it will bottom out.  There is no risk with bottoming it out, and you'll know when you do because it will go from difficult to turn, to impossible to turn.

When you move the tuner "all the way out", you'll eventually remove the cap entirely.  This "burping" of the etalon is actually a step that is called out in the manual since it exposes the cylinder to atmospheric pressure and is a way to "reset" the etalon.  If there is a tiny leak, and you leave it screwed all the way in, you won't be able to build enough pressure to bring it on-band until you let more air in some how, and that is what "burping" the etalon accomplishes.

That said, every etalon is different.  In my case, if I burp the etalon, it comes on-band literally 3-4 turns in.  By time I even get halfway in, the etalon is completely offband and I'm able to see sunspots clearly.

If you are using a camera, one thing you can do is intentionally defocus the sun to remove plages and other bright features, and then tune the etalon while watching the live histogram.  You should see the peak brightness of the histogram drop to the low end.  Eventually as you continue to tune the etalon, the peak brightness will stop moving downwards and start moving back up.  Right at the minimal point is where you have maximized the attenuation of the photosphere and your etalon should be on-band.  Simply focus and enjoy the view.


Edited by jwestervelt, 07 May 2021 - 12:53 PM.

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