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ASI focus?

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#1 resq

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Posted 14 July 2015 - 10:24 PM

Hi,

I just got an ASI120MC for general all around imaging through my 10"dob and my Lunt 50 B400 telescope. I cannot sem to get any focus or detail in the Lunt. I have used Fire capture and Sharp Cap. And use Autostakkert for stacking. I have tried to extend the nose piece from the ep holder, and actually achieve best focus when I remove the nose piece all together. But I cannot hold the camera and get just ok focus. I dont even know what to look for when looking at the computer screen with the sun. I assumed it would look somewhat like it does through the EP. Heck, my cell phone can do that. Should I be able to see any details (proms, filaments, or surface) on the computer screen when capturing?



#2 nickatnight

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Posted 14 July 2015 - 11:36 PM

Hi RESQ.

 

There are a few combinations of adapters I use to reach focus depending on no barlow or barlow. With no Barlow, screwing the camera onto the eyepiece holder sets it too far back. You need to unscrew the eyepiece holder and screw on an adapter that's about half the length of the eyepiece holder. I have this, but there may be cheaper versions:

 

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

 

As an alternative, you can remove the eyepiece holder, screw the camera directly onto the diagonal, and then slide the diagonal further back out of the telescope, again about the same distance as half the eyepiece holder. This works fine, just less solid of a connection with the diagonal slipped out a bit.

 

With barlows, I have not been able to directly connect them to camera. I chose barlows that the front 1 1/4" barlow element can unscew from it's eyepiece holder. For these I leave the diagonal eyepiece holder in place, drop the unbscrewed barlow element down the eyepiece holder, and then screw the camera directly on the eyepiece holder.

 

This barlow works but when dropped down the eyepiece holder give about 1.6x instead of 2x.

 

http://agenaastro.co...arlow-lens.html

 

And this one works using same method, but give 2.2x instead of 3x.

 

http://agenaastro.co...rlow-07278.html

 

Hope you find all this helpful and feel free to ask any other questions. I'm relatively new at this too, and have had great support from folks here. I'll add this info to your post in the forum too, in case others are looking for similar answers.



#3 resq

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Posted 14 July 2015 - 11:47 PM

Awesome!! Thanks Nick! Which adapter do you have? Male or female? I'll pick one up and probably get a Barlow. Which one works well for you? Thanks again!! Your pictures are awesome! 



#4 Seldom

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Posted 14 July 2015 - 11:56 PM

resq, can you see the edge of the disk, but just not get it in focus?  It can be hard to find the edge of a far out of focus sun.

 

I've got an ASI120MC with FireCapture, and this the FOV from my LS80THa.  The camera nosepiece replaces the eyepiece.  The eyepiece shows the full disk, but the ASI120MC sensor is smaller.   Some re-focus is also required.  I do this with my head under a blanket holding and viewing my laptop with one hand while focusing the scope with the other.

 

2015-07-13-1535_0-L-3_g6_ap636_conv.jpg

 

FYI, I'm newer at this than nick.  I use 2.5x and 5x Powermates for magnification, but don't need either to focus my camera, unlike my dob, where I need a Barlow to focus.


Edited by Seldom, 14 July 2015 - 11:59 PM.


#5 resq

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Posted 15 July 2015 - 12:42 AM

Hey Seldom! I can and cannot if that makes sense. I think it just needs to get closer to the little eye hole of the diagonal. How did you get that picture?! Is that what you see on your laptop? I would be thrilled with that! That's exactly what is seen in the EP!  I get roughly that same FOV. I'm going to try to post a picture of what I get...  Ok it won't let me post a picture from my cellphone (just wants the url). Basically a fuzzy ball at all focus points on my dial. 



#6 nickatnight

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Posted 15 July 2015 - 02:29 AM

Hi Resq, I have the Male C-Mount to Female T-Mount Adapter. The male C-Mount screws into the ring shaped adapter that the stock fisheye camera sits in, and then the female t-mount screws on to the diagonal, either with or without eyepiece holder depending on using a barlow or not. As for the barlow, I almost always opt for the 3x linked above, which as mentioned give 2.2x dropped down in the diagonal. My 2x barlow I have left screwed onto the end of my Lunt Zoom eyepiece. I feel it really makes the zoom work better for the small scope, and see no reason to every take it off.

 

As you'll have to order those adapters etc, just give the "sliding the diagonal out" method a try. It actually will easily put you in the reach of focus with the ZWO camera.

 

Also, as Seldom mentions, Powermates work well. I have a 5x but it really pushes past the limits of the LS50. I've been tempted to pick up a 2.5x. Again with the Powermates, I had to rig it up with the Powermate T-Adapter, as using it in it's normal state with an eyepiece holder was impossible to reach focus.


Edited by nickatnight, 15 July 2015 - 02:34 AM.


#7 Seldom

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Posted 15 July 2015 - 02:06 PM

How did you get that picture?! Is that what you see on your laptop? I would be thrilled with that! That's exactly what is seen in the EP!

I took that with my ASI120MC using its standard nosepiece in my diagonal.  My blocking filter's a B1800.  I don't know if that would make any difference or not.

It's pretty much what I see in FireCapture, although after AutoStakkert it's a little sharper.  I use this as a quarter of a full sun mosaic, so I just use the sharpening switch in AutoStakkert without any wavelets from Registax.

 

My guess is that you are trying to focus in FireCapture with your exposure settings too high.  The exposure to give the most Ha detail for an RGB camera like we're using would be to center the Red histogram, and leave the blue and green off to the left.  This image will be noticeably dimmer, but more detailed.  When you set the exposure correctly, you'll find that the focus moves significantly. 

 

I thought I could calculate the difference between red and white (use green) light focus, but I'm not having any luck there.  I tried solving for FWHM of green on an F7 scope, and then seeing what focal length would give the same FWHM for Ha light, but the difference was way more than I'm seeing at the eyepiece.  Any pointers would be appreciated.


Edited by Seldom, 15 July 2015 - 06:16 PM.


#8 resq

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Posted 15 July 2015 - 08:17 PM

I just tried doing some imaging. I unscrewed the ep holder and put the camera directly to the diagonal. I still get the white disc and red buffer look. Maybe its an exposure thing. I dunno. And I cannot post the pictures here because it asks for an URL and I only have stuff on my desktop and phone. I am a little frustrated. I want images of the sun! lol I am just baffled. I did not slide the diagonal out any. Maybe that would help some. I dunno. Am I supposed to see details in the disc and proms in the capturing software? How do I adjust exposure? Firecapture seems very useless. I cannot even see any image. Just a faint fuzzy glow circle under a thick black grid. I have a video but it wont let me post it. lol I can email it to someone to see if they can see. Then I can send what I am getting in sharp cap too and maybe someone can help!



#9 nickatnight

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Posted 15 July 2015 - 08:31 PM

If you didn't slide the diagonal out any, you won't get focus. That proper distance is everything. Everything. Everything.

Once you can focus, then you'll get details and be able to set exposure. If I don't focus I get a featureless gray or white disk depending on exposure.

Edited by nickatnight, 15 July 2015 - 08:35 PM.


#10 Seldom

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Posted 15 July 2015 - 08:52 PM

I haven't tried this, but can't you just shoot & stack your out of focus image in FireCapture?

Regarding exposure: set it for sun. There's a set of exposure options: sun, moon, jupiter, dso. The author has also posted a fine Youtube tutorial. It uses a beta version that's much better than the one on the ZWO disk.

Edited by Seldom, 15 July 2015 - 08:58 PM.


#11 resq

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Posted 15 July 2015 - 09:08 PM

Ok, I got good focus by sliding out the diagonal ( Thanks Nick ) but still zero details. Stacked images are much better, but zero details or proms.



#12 resq

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Posted 15 July 2015 - 10:24 PM

Here is the best I can get. This is with the best focus I could achieve and all wavelets half to the right in registax lol. Sunbest_zps2oswivtx.jpg



#13 resq

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Posted 15 July 2015 - 10:39 PM

Here is the stacked image but nothing done in registax. This is straight from vid in firecap to autostakk. sun1_zpsw4goml2k.jpg



#14 nickatnight

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Posted 15 July 2015 - 11:11 PM

On the right track now it seems. Your exposures are way too long. As Seldom said, make sure your in the "Sun" range of exposures. You should be able to move the slider left until the image is exposed properly. If the exposure slider is all the way to the left, then your not in the "Sun" range of exposure settings.

Also to note is as you have a color camera, there are sliders to adjust color of each channel. It might be helpful to reduce the red, as it tends to overexpose quickly on the sun.

Edited by nickatnight, 15 July 2015 - 11:15 PM.


#15 resq

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Posted 15 July 2015 - 11:14 PM

Which slider?? I am using the "sun HA" setting.

#16 nickatnight

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Posted 15 July 2015 - 11:19 PM

The exposure time slider. It should give you an exposure time in ms (milliseconds). I don't have my computer in front of me, but it should be just to the left of the drop down list you use to select the "sun" range of exposure times.

With that slider, I get good disk exposure with it almost all the way left, and good prom exposure all the way right.

It'll be like magic when you find it. :-)

Edited by nickatnight, 15 July 2015 - 11:24 PM.


#17 Seldom

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Posted 16 July 2015 - 01:26 AM

Also to note is as you have a color camera, there are sliders to adjust color of each channel. It might be helpful to reduce the red, as it tends to overexpose quickly on the sun.

I haven't found those individual RGB sliders yet, but I've been able to manage exposure by maximizing the red histogram and letting the green and blue histograms stay minimally to the left.  Red is the color that's coming through the scope, so I figure it's the one I should give most value to, and if you only expose based on the red color, the red doesn't get burned out.


Edited by Seldom, 16 July 2015 - 01:29 AM.


#18 resq

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Posted 16 July 2015 - 10:41 AM

Awesome! Hopefully I will get a chance to play with it a bit tomorrow! Thanks again for bearing with me on this one! I was expecting more of a plug and play lol



#19 Lowjiber

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Posted 19 July 2015 - 02:23 PM

I'm following this thread closely, as I purchased the same scope as resq, with the B/600 diagonal.  My new cam is the ZWO ASI120MM (monochrome), and I can't get focused either.

 

I just ordered the 2x Barlow that Nick recommended above.

 

I'm a new solar observer and having fun with the visual stuff.  Now, I want to get the cam working.

 

Thanks everyone for your comments, and thanks to resq for putting me on this thread.  It is very helpful.

 

Clear Skies

 

John




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