strange things!!!!!!

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strange things!!!!!!

Post by denababy » Sun May 20, 2018 12:04 pm

12_13_51.CameraSettings.txt
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I have tried and tried but cannot fathom this problem. When I take an out of focus shot to be used as flat calibration on the surface I only change the focus and nothing else. When I then open the surface vid and apply the out of focus vid I get a shadow and where the sky is (should be) black there is also a strange mottled effect, when I apply the stacking points they also go over the mottled bit and not only on the disk. I have tried different things but no change, it is ok when I remove the master flat. I cannot upload a pic as it happens in Autostakkert and I do not know how to take a screen shot then load it into here. I think my tracking is OK as the image on my screen does not move. I need to sort this as I do not want NR's on my images, can anyone help please. I know a pic would help but unless I can take a screen shot and upload it text is all I've got sorry.
12_13_51.CameraSettings.txt
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Re: strange things!!!!!!

Post by PDB » Sun May 20, 2018 3:15 pm

Hi,

Are these images full-disc? Then I think it will be impossible to make a flat like that. The Sun getting dimmer at the rim will also be visible in the out of focus capture. That makes the flat incorrect, because it will get dimmer in places were it should not.

You would need to change focus probably a lot, but then the image will get very dim and the flat probably does not have the effect it should have either.

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Re: strange things!!!!!!

Post by FlankerOneTwo » Sun May 20, 2018 4:24 pm

A flat has to be evenly illuminated across the entire frame, not just where the image is light, so out of focus flats don't work if there are portions of the solar limb and background dark space in view. Otherwise the dark areas of the flat make the program think you have crazy vignetting and it will attempt to drastically lighten the dark areas of the image.

I have had some success with filling in the dark areas of the flat with a gray calculated to match the average value of the illuminated flat (have to carefully fade the transition zone), but it's not 100%. A better approach would be to try to get a true uniform flat, either against an area of blank sky or with a bag flat (although I've never managed to get this to work very well).

Neither is a great way to get rid of newton rings, you may find that a camera tilter works a lot better. Daystar Interference Eliminator did the job for me. The ZWO tilter did not have enough travel to eliminate the rings that I was getting from the ASI1600. I only use flats only for dust bunnies and the like.

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Re: strange things!!!!!!

Post by PDB » Sun May 20, 2018 4:39 pm

you may find that a camera tilter works a lot better.
Very true, the only good way to solve it, but this might not be possible on an LS/50 in prime focus because it will make the distance camera/scope longer and that could make it impossible to focus again. (That scope has very limited in-focus distance)

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Re: strange things!!!!!!

Post by Bruce Girrell » Sun May 20, 2018 5:15 pm

Denababy -

You are still using an extremely short exposure time. Move that up to at least a couple of milliseconds until we get this figured out. You will need to drop your gain accordingly to keep the image brightness from clipping. Always keep your histogram up (though you can shrink its height considerably from the default).

Otherwise, everything looks pretty much OK in the camera settings.

To export a single frame (or multiple frames) from AutoStakkert, use the Export Frame(s) control at the top right of the image window. Click Current and the program will bring up a normal Save As dialog. Save the image as a JPEG or PNG for posting here. To get the full raw image, use FIT. For a screen capture, look for a PrtScn or similarly named key on your keyboard. If you have a laptop, you may need to use the Fn key. Create a new canvas in Photoshop or whatever image editing program you are using, then paste the image onto the canvas. In Photoshop, you will have to flatten the layers before saving to a JPEG. If you have a Mac, use Command+Shift+4. You then use your cursor to drag a selection rectangle over the area that you want. When you finish the selection, a copy of the area that you selected is saved to the desktop in .PNG format.
AutoStakkert Export Frames1.jpg
AutoStakkert Export Frames1.jpg (388.11 KiB) Viewed 625 times


I can't help much with the flat, though it is sometimes possible to use a heavily median filtered version of the image as a flat. Regarding the actions that Autostakkert has taken in your "mottled bits", I think that most of what it is doing can be explained by looking at what the Min Brightness setting does.

When you click on the Place AP Grid button, the program looks to see what the Min Brightness setting is, and it won't place any APs anywhere in the image where the brightness is less than that. In my example here, Min Brightness has been set to 35. The disk is fully covered, but certainly there is something interesting going on at the limb and that, being the most interesting feature, is not being represented well with APs, see inset.
AutoStakkert AP grid1.jpg
AutoStakkert AP grid1.jpg (980.48 KiB) Viewed 625 times


If the Min Brightness setting is reduced to 15 in an attempt to force more APs along the limb, the result is this:
AutoStakkert Min Bright 15_1.jpg
AutoStakkert Min Bright 15_1.jpg (909.7 KiB) Viewed 625 times


Now there are a bunch of APs out in blank space, which isn't going to be helpful at all to the stacking process and can only slow things down, at best. Changing the display brightness also has a major effect on how AutoStakkert sets APs. Here the display brightness has been set to 2 and Min Brightness is back at 35. AutoStakkert tells us that changing the display brightness does not affect the data, which it doesn't, but it definitely affects how the APs are set. AutoStakkert apparently will not use a clipped brightness for the location of an AP, so now there are no APs at all on the disk and everything is out in space.
AutoStakkert Display Bright 2x 1.jpg
AutoStakkert Display Bright 2x 1.jpg (597.64 KiB) Viewed 625 times


I don't know what your flat looks like, but I'm hoping that this explains at least some of what is going on with the APs being placed over your mottled areas.

Just to continue one bit further... Clearly, when I do want to tell AutoStakkert to be mindful of detail in the proms and the disk at the same time, AutoStakkert has a difficult time. I handle the situation by letting AutoStakkert do all of the APs on the disk automatically. I like using the Multi-Scale option that has been added in Version 3.1. After the automatic picks are done, I set the display brightness to whatever allows me to see the proms clearly. I clear the Draw APs checkbox, which clears the clutter of the existing APs so I can see what I'm doing. Usually I set the AP size lower by one or two steps, depending on the image. Then I go around the image, manually adding APs anywhere that I think they will help. Simply left click to place a new AP. Right click on APs to delete them (you may have to turn them back on in order to see which one you are deleting). Do not check the Manual Draw checkbox. Use the Manual Draw checkbox when you want to manually add rectangular APs instead of square ones.
AutoStakkert Proms1.jpg
AutoStakkert Proms1.jpg (404.29 KiB) Viewed 625 times


I suggest that you trim your workflow to the bare minimum. Don't worry about Newton's rings, don't worry about flats. Avoid extremes in any direction for any of the camera settings. Get a good image out of AutoStakkert first, then you can start adding the changes back in.

Keep a record of what you did and post the results when you need more help

Good luck

Bruce G

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Re: strange things!!!!!!

Post by denababy » Sun May 20, 2018 5:46 pm

Thanks Bruce G I will read and reread your post, really great information thanks. Paul, I have Four ccd cameras but the only one where I can achieve focus is the zwo. I have replaced the Hellical focuser with a Feathertouch one. I am hoping tomorrow (Tuesday 21st May) will be sunny so I can put suggestions in place and hope I can solve this, I don’t want to just overcome it I want to get to the root cause and cure it.

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Re: strange things!!!!!!

Post by THEO BAKALEXIS » Sun May 20, 2018 5:48 pm

Try to upload a video of your observation.
All the conversation is on air.
Try to show us step by step your movements.
Image

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Re: strange things!!!!!!

Post by THEO BAKALEXIS » Sun May 20, 2018 5:53 pm

Your problem i suppose.

You can`t take videos with details in your observation.....?????
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Re: strange things!!!!!!

Post by denababy » Sun May 27, 2018 1:14 pm

Bruce can I ask what your equipment is. Mine is a Lunt ha50 and although it is advertised as being ok for Imaging it really is hard work. I would love to get the detail on the proms you have in your post above. I have been thinking about getting a Quark and putting it on my Explore Scientific 80apo. Today (Sunday 27th May) I managed to take some videos but there is little detail certainly on the proms. Maybe I’m expecting too much from my Lunt and could possibly achieve better from a Quark. The camera I use, and the only one I can get focus with, is a ZWO 120mm. I have also a DMK 21 and an Altair Astro 8gm do you think I would get better results using a different camera than my ZWO and a Quark?

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Re: strange things!!!!!!

Post by Bruce Girrell » Sun May 27, 2018 2:20 pm

I use a Lunt LS80, so I have some more aperture than you, but if you look around, you'll find a number of good images done with a 50mm scope.
I (mostly) use a ZWO 174MM camera and I use SharpCap for capture. I have just recently purchased SharpCap Pro V3.1, but all of my responses are based on SharpCap V3.0, as I haven't even had a chance to try the new software yet.

I almost always shoot* with my gamma near 50. The lowest (darker, higher contrast) gamma I use is about 35 and the highest (more proms, but less contrast) is 65. I chose those limits based on the behavior of the histogram. By doing so, I can usually retain prominences on the limb along with detail in the disk. I don't like to do separate exposures for the proms and for the disk, but that's my own preference. I guess this won't matter much going forward, since SharpCap 3.1 eliminated the gamma control for ZWO cameras.

The gamma curve is/was a software correction. You can see this by examining the histogram. If a software gamma is being used, the histogram will break up into individual bars as you push one end or the other of the range. An analog amplifier (hardware gamma) would produce a histogram with no gaps, no matter what the setting since, if nothing else, noise will always be available to fill in. Since the gamma curve is software, you can accomplish the same effect in Photoshop. Changing a software gamma changes nothing about the information coming from the imaging chip. Essentially, you should shoot with a neutral gamma and then operate on the resulting image with whatever software tools you have.

I also don't set my gain above about 225 (necessary to keep exposure time reasonable when using Barlows) because it appears that the camera switches from hardware gain to software gain around that point. I _always_ shoot 16-bit and I don't understand why anyone would use 8-bit when dealing with the huge image dynamic range that we have with solar images.

Keep trying. It sounds as though you're seeing some degree of progress. When you get some new results please post and we'll have another go at it.

Bruce G


* For focusing, all bets are off and I frequently use high contrast settings for both my image gamma and my display gamma. But as soon as I am comfortable with the focus, the image gamma gets set back to the middle. I often jockey the display gamma around for various reasons

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Re: strange things!!!!!!

Post by denababy » Sun May 27, 2018 4:15 pm

11_06_11_g5_ap1574.png
11_06_11_g5_ap1574.png (1.85 MiB) Viewed 510 times
Hi Bruce thanks again for your reply. I have both versions of SharpCap (3.0 and 3.1) I now mainly use version 3.0 so that I have some control with Gamma, I cannot understand why this control was taken out of V3.1? I use the histogram to achieve between 80 and 90 and then up my magnification from 75% to either 150 or 200% to get focus. I have tried to set the exposure higher, the gain to about 15-20 and the gamma to 50, I have to play around with the three settings until I get a fairly even coloured disk so it is not possible to set the exposure any higher as it just blows out the disk to just white, even if I adjust the gain and gamma. It would be interesting to find out what settings others use more specifically those with a Lunt 50. Here is a pic I took today.

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Re: strange things!!!!!!

Post by Bruce Girrell » Sun May 27, 2018 6:04 pm

The reason that gamma adjustment for ZWO cameras has been eliminated from SharpCap 3.1 is because the latest camera driver from ZWO eliminated the control. There is nothing for SharpCap to adjust. Since the gamma adjustment was a software adjustment, it really had no effect on the data that could not be equaled by post-processing. In other words, if you record the raw image directly as the imaging chip saw it, then whatever you could have gotten from a gamma adjustment, you can get from Photoshop.

You're making progress. At least there is some recognizable detail today. I processed your image a bit more (and I wasn't very careful) to boost the contrast. Your etalon is a bit off, making the lower left of your image considerably brighter than the remainder. I balanced that out in my processing. You should be getting better detail than what you have, but you're clearly going the right direction.
11_06_11_g5_ap1574a.png
11_06_11_g5_ap1574a.png (2.38 MiB) Viewed 504 times
I have reasonable seeing here today. I built a mask to hobble my telescope down to 50 mm and I inserted a reducer to make my telescope's focal length more similar to yours (I'll have to calculate the effective focal length once I look at the photos). I took some images that should be close to what you should expect from your scope. I'm processing them now and will post again when I get them done.

Bruce G

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Re: strange things!!!!!!

Post by denababy » Sun May 27, 2018 6:55 pm

That is fantastic, just goes to show when you know what you are doing things happen. I did notice that there was at least one prom but as you can see it is not visible.

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Re: strange things!!!!!!

Post by Bruce Girrell » Mon May 28, 2018 5:14 am

Here is what I did this afternoon. I used a simple mask to reduce my aperture to 50 mm. In addition to matching the aperture, I need to adjust my focal length to match yours. My scope has a focal length of 560 mm and yours is 350. I intended to use a reducer lens to compensate, but I couldn't achieve focus with the lens in place. I was able to modify things a bit, but the best I could do was to get my focal length down to 450 mm. Close enough for what we're doing.

If we're getting fussy, we should compare camera pixel sizes. My camera is a ZWO ASI174MM, which has 5.86 micron square pixels

Here is the image that I got with that setup

DB disk2.png
DB disk2.png (1.69 MiB) Viewed 481 times
So this represents something on the order of what you should be expecting to see in your images.

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Re: strange things!!!!!!

Post by denababy » Mon May 28, 2018 9:10 am

Wow is all I can say, it gives me something to go for. Thanks for your time. Today the skies are totally clouded out and to make things a little bit worse, the next door neighbour have their fire lit and it is a wood burner so plenty of smoke to add to the glumness. As soon as I can, weather permitting, I will post my next attempt.

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Re: strange things!!!!!!

Post by Bruce Girrell » Mon May 28, 2018 9:49 pm

Just for comparison, here is the same thing, using the full 80mm aperture (and no reducer). This was shot about 15 minutes after the shot I posted previously, so the seeing should be almost the same.

2018_05_27 Full disk 80mm2.jpg
2018_05_27 Full disk 80mm2.jpg (245.5 KiB) Viewed 461 times

There is more detail here, but not a ton more. Note, however, that there is a lot to be gained in detail from auxiliary lenses, as you can see in my other post from today:
viewtopic.php?f=4&t=24532

Those pictures were shot in the same imaging session as the ones above.

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Re: strange things!!!!!!

Post by denababy » Tue May 29, 2018 9:03 am

Yet again wonderful. I have tried with different lenses such as a Celestron Barlow x2 and a Powermate x2.5 but cannot get focus, it must be a Lunt thing. I have changed the focuser from the original helical one to a Feathertouch,but still the same issue with focus. With the pic above you can see a prom about ten o’clock which is something I did not achieve. Thanks for posting.

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Re: strange things!!!!!!

Post by PDB » Tue May 29, 2018 10:18 am

Can you post a pic of your setup? Especially focuser -> blocking filter -> camera

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Re: strange things!!!!!!

Post by denababy » Wed May 30, 2018 10:52 am

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_MG_0298.JPG
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Hopefully here are some pics of my scope Etc. but without and cables.
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Re: strange things!!!!!!

Post by PDB » Wed May 30, 2018 11:05 am

hi,

thats ok. Well don't think you can get your camera closer. The distance from sensor to where it touches the black ring on the blocking filter is 12.5 mm
(There is one way to shorten, but then you need to unscrew the front plate from the camera, and find an adapter that fits that thread on the camera side. Think you then get 5mm distance) There is an adapter that screws on the camera like that, but it is for a nosepiece so that does not solve your situation)

I am surprised you can't focus with that setup. ASI 120 has a fairly short distance sensor-camera side compared to PointGrey and some on this forum are able to get focus. Have you tried different possitions of the blocking filter in the focuser?

Rgrds,

Paul

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Re: strange things!!!!!!

Post by denababy » Wed May 30, 2018 12:23 pm

Hi Paul I am able to get focus but not with any Barlow Etc. in the Imaging train. I move the blocking filter out by about 10mm to achieve focus and the only camera I can get focus is the one in the pics. I have a DMK 120 , for which I purchased a shorter adapter and an Altair Astro gm8 which, when I bought it, I was told to use a Barlow but I have never gotten focus with either. I have tried to put the blocking filter in the home position thinking it would help getting focus as there is not enough inward travel, I have tried various setups with all the cameras I have to get focus but with no luck.

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Re: strange things!!!!!!

Post by PDB » Wed May 30, 2018 12:32 pm

Ok. Now I see. Are you able to get focus with an eyepiece in the barlow? Normal barlows or Powermates (telecentric)

P.

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Re: strange things!!!!!!

Post by denababy » Wed May 30, 2018 1:17 pm

No. I have tried various combinations with barlows and my Powermate x2.5 but have to revert to just the camera. I have been thinking of getting a Quark to put onto my Explore Scientific 80apo but at just over £1000 it really has to make a massive difference. If there was an astronomy shop near where I live maybe I could talk to them and maybe even try things out before buying.

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Re: strange things!!!!!!

Post by Bruce Girrell » Wed May 30, 2018 4:57 pm

While your telescope model is not the same as mine, I would think that Lunt would try to keep design elements similar from model to model whenever possible. I am very surprised to see how close the camera is. On my scope, I have to pull the drawtube _out_ in order to achieve focus. Are you sure you're seeing the main image, and not a reflection of some sort? I suggest (with the telescope pointing at the Sun) starting with the focuser in the middle of its range. Then, while looking through the eyepiece (set at lowest magnification, probably 21mm, if it's the standard Lunt eyepiece), slide the drawtube in and out until you get close to a sharp image. Don't worry about surface detail, we're just talking about a sharp edge to the disc. Once you get close, you can use the focuser to get it right on.

Once you have the optical focus right, give the etalon an initial tuning so that you have something to see with the camera. Then attach the camera with no Barlow. Make sure your SharpCap zoom is set to Auto, at least until you can find the Sun properly. Loosen the screws on the drawtube and slide it around until you can see the disc close to being in focus on your screen. I usually have to pull the drawtube _further out_ in order to achieve focus, and my camera is not screwed directly to the BF the way yours is*. Your setup looks really tight to me, though if there's someone here who has a LS50, they probably have a better idea of haw far away the camera should be.

May you have some clear skies soon

Bruce G


* I used to screw my camera on to the BF, but unscrewing it with cables attached is a problem and I didn't want to shut down the software just to add a Barlow. ZWO supplied a short tube with my camera that screws on to the camera's threads and slips into the eyepiece holder. Look in the box your camera came in and see if they gave you one also. It makes changing Barlows, or even changing cameras, much easier

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Re: strange things!!!!!!

Post by PDB » Wed May 30, 2018 5:19 pm

Hi Bruce,

the LS50 is know for its very limited backfocus. So placement of the camera looks ok to me. Did some reading on barlows and the LS50 and if I understand it correctly some place the barlow before the diagonal. To get necessary infocus that makes sense to me. Only thing I don't know if it will be safe for the barlow. (Would not try it with an expensive PowerMate)
There should be something that works. Astrograph is telling this on his website: http://astrograph.net/Lunt-50mm-H-Alpha ... sure-Tuner

Maybe he can enlighten denaby about the placement of the barlow in the optical train.

Regards,

Paul

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