Lowjiber

Hi again, Tony Your details are amazing in the properly exposed (3/4) of the disk. Thanks for posting it. I've had a similar problem with my Lunt 60PT/BF1200 in the past. Both times it was caused by the etalon being a little slow to completely adjust to my tuning settings. (I know this shouldn't be the case, but here's what I did.) I removed the piston assembly to clean and re-lube the piston/o-ring. The lube that was present beforehand had become slightly "stiff" with use. By "servicing" the piston assembly, I immediately saw (felt?) a smoother movement when adjusting. Like your disk above, I was so close with the correct tune, but the etalon was reacting very slow to my adjustments causing my heartburn. I also developed the habit of cranking my tuner knob completely in (clockwise) and making my tuning adjustment by backing off the knob (reducing the pressure inside the etalon, vice increasing it by turning clockwise) to make my adjustment. The bottom line is the etalon is always "behind" your knob setting by just a bit... taking too much time to "catch-up". By cleaning/re-lubing the piston and turning counter-clockwise to slowly make the adjustments, the etalon is able to react better to the very fine adjustments needed to level the histogram. I know that may seem like voodoo, but it works. Following up on the above, I'll add that I crank my tuner knob completely clock-wise and let the scope set for about five minutes before beginning the (outward) adjustment. That "habit" has served me well with two LuntPTs over the past five years. I'll add that a perfect gradient adjustment will be when the center of the sun is slightly brighter than the surrounding surface... revealing the sphere-like nature of the sun. Hope that helps. Clear Skies

Switching to FC is not going to fix a partial over-exposure issue. Can you post a typical image to give us an idea of just how over-exposed it is? Typically, the sun is brighter toward the center of the sphere. When shooting the surface, adjust the exposure and gain to attain between 60 & 70% on the Log scale.

Excellent work, GA. Thanks for the contributions. Clear Skies

Michael, I want to thank you for this thread. I've overlooked it previously, but decided to read it carefully yesterday. I had never been successful with ImPPG previously, usually ending up with "junk" when trying to set the compound curves and the sharpening settings. Your simple explanation and the screenshots finally pounded it through my thick skull. I "played" with it all day yesterday. Thanks Again! Clear Skies

Paul, regards your new ASI120MM-S, we have a saying in the US... "That dog will hunt."

I'll second everyone's recommendation of the ASI120MM. Make sure to get the "-S" model, as it's USB 3.0 and can deliver faster data. Monochrome is the only way to go in my opinion for solar work. A mono cam uses all of the pixels, whereas the color cam of the same size only uses the red channel... only one-fourth of the pixels. Clear Skies

I can't really testify regarding that model. Try Googling " DMK21AU618". There are some reviews of that cam there.

I have two ASI174MM cams that are both cooled. There is a tilter on one and not the other... just because I'm lazy. LOL I also have an ASI120MM-s cam that is not cooled. The "-s" means it is a USB 3.0 model and the "MM" on all of them indicates that they are monochrome. Cam cooling is often not necessary. However, I live in the desert southwestern US where average daily summer temps average 117 degrees Fahrenheit. It those temps, a cam's chip can become overheated resulting in dropped frames and a signal-to-noise ratio that is uncomfortable to deal with in post-processing... to say the least. I was out for a one-hour session today where the outside air temp was only 68 degrees (F) and the SharpCap cooling control never even turned the cooler on. I use SharpCap for my imaging software. SharpCap will monitor the chip temps for you during imaging. I just refer you again to my earlier thread in which I recommend a USB 3.0 cam. If the cam offered locally is not a 3.0 version (with the "-s), I would avoid it. It's not that you can't use it, but the 3.0 protocol is where we as an imaging community are currently at because of the advances in personal computers.

I only recommended a fast processor because they're not that much more expensive than the slower ones. As long as you're pumping USB 3.0 data out of the cam, you'll be fine. However, a slower processor may drop some frames at the higher capture rates. Don't let that be a show-stopper for you. Best,

There is excellent advice in all of the posts above. I'll just throw in my "opinions" for consideration. I have the same Lunt that you have that I use primarily for full-disk shots. If you use an ASI120MM cam with it, you won't get a full-disk image because the chip is too small, but you can always do a mosaic for a full-disk... just more processing work. Cams: The older DMK 21's are nice, but the frame rate is pretty low and they are hard to find used here in the US. I use an ASI174MM-cooled cam (I have two) for almost everything solar-wise. The 174 is a rolling shutter, but ZWO has incorporated firmware that electronically duplicates a global shutter, thus eliminating the artifacts mentioned above... works great. I have never shot without a tracking mount, but know several who have. I encourage you to at least look into a Celestron CG-4 that will accept an RA tracking motor. CG-4's are fairly inexpensive and a tracking motor is less than $100 (US). When you've got your head stuck in a dark box setting up a shot, it's nice to have the mount tracking the sun, leaving one less thing to "worry about". I usually shoot around 1000 frames at 60fps; stack in Autostakkert3; adjust wavelets in RegiStax6; and finish processing in Photoshop. I have Lightroom, but it is better suited for pictures of your kids playing with the dog... In my opinion. Stick with PS or GIMP. Computers... You want as fast of a processor as you can afford, and USB-3 ports are a must as the world has long-since passed on the slower USB-2. I will warn you here that the data cable supplied with ZWO cams is often a failure point, even when new. That's not a big deal as $20 (US) will set you up with one that can handle the faster USB-3 data. One last word about barlows... You likely have seen these super-close prom shots that we post. Those are shot with a Quark that contains a built-in 4.3x Barlow lens. If you want close-ups with the Lunt 60 you'll soon find that anything over about 3x is unsuitable. I use a 2.5x Powermate when I want to get up-close-and-personal with the Lunt. Best of luck in starting your solar imaging adventure... It's addictive.

I think I know the date of the one that you couldn't remember... OCTOBER 25, 2017. How did I remember it? Read the text that I added to the same prom shot, and it will explain it. It's weird how we solar imagers remember such things. Here it is...

Very nice, Charl. Thanks for taking the time to share them. Here's a few from 2017 that I liked...

Truth be known, the only time I've fallen in the pool was during the daytime. The pool edges are curved, and I was walking back to the scope area and not paying attention... literally walked into the pool. Fortunately, I didn't have my cell phone in my pocket and the only "serious" thing that got wet was the Glock on my hip. Lesson Learned.

AR152 with an ST-80 finder on Twilight II mount.

I use one for a slightly different purpose... visual observing. In my light-polluted backyard, I have varying degrees of darkness depending on the amount of light glow from the Las Vegas strip, the Moon, and other variables. It may seem wierd, but it is really handy when even attemptng dim fuzzies at various angles in the sky. I need (want?) to know how dark a particular area is in the sky. The company makes a version called a "Sky Quality Meter with Lens" (SQM-L) that measures only a 40o cone around the direction (up/down/left/right) it is pointed. The readings are the same, but sometimes I find it easier to "get my head around" the somewhat simplier Naked Eye Limiting Magnitude (NELM) numbers. Below is a conversion chart that helps. SQM readings aren't for everyone, but those of us who use 'em sure do like the results... just another "tool". Clear, Dark Skies

When magnification increases (shorter focal length eyepieces), surface brightness decreases. I know it sounds strange, but increasing the power makes the target dimmer, but (big "but" there) the background sky gets much darker as well. Hence the increase in contrast. I have a 31mm Baader Aspheric. It's AFOV is 72o. My DSO "hunting" eyepieces are: 31mm Hyperion, 2" ES 82o eyepieces in 24mm & 18mm. Once I find a target, I drop down in focal length, usually one step at a time, until the contrast is better. Obviously, there is a stopping point, but it will amaze you. As we used to say..."Try it, you'll like it."

First off, I feel your pain. I live in the middle of a super nova named Las Vegas, Nv USA. Secondly, I recommend Rod Mollise's great book entitled, "The Urban Astronomer's Guide". Amazon carries it. The interesting thing about light polluted skies is that you can actually find "fuzzies" better by increasing the contrast... making the background darker. Adding something like a 17mm Hyperion or an 18mm ES 82o eyepiece to your collection can really help. Getting close (or even finding) the target with your 28mm and then increasing the power slightly with a mid-range EP can often enhance the contrast and allow a better overall view. Yes, the target gets dimmer as you increase power, but the difference in contrast more than makes up for that slight loss. Clear, Dark Skies

I have a pair of Celestron 12 x 70's that I can hand-hold pretty well. I have Oberwerk 15 x 70's that get most of my use... mounted on an Oberwerk Heavy Duty, Adjustable Monopod. (solid) I also have a pair of Celestron 25 x 70's that I use on the monopod above as well. Clear Skies