Post by Rick in NWArk on Jul 16, 2015 4:55:53 GMT
(Continued from Part I)
... and so the sun set on our intrepid adventurer and space explorer *ahem* oh yeah back to the review...
Darkness is falling but not quite there, so I go ahead and collect my Dark Frames. I have already put the camera in the scope, so I just leave the scope cap on and take the Dark Frames that way. You can collect the Dark Frames by just leaving the cap on the camera and not have it in the telescope. This is risky to me because if I were to accidentally unplug the USB while putting the camera into the scope, I would lose all of my Dark Frames and the time it takes.
I go with 10 frames of 30 seconds. If I remember right, this is what Chris A. started with and if its good for Chris, its good for me, right? Haha I initially forgot that Dark Frames are also subject to the interlace method of image acquisition so it was slower than I thought. For those of you that are not familiar, these cameras work through what is called interlacing -- think about the image being composed of 582 horizontal lines. With a progressive scan, every line is read until the whole image/chip is pulled. With an interlace scan, every other line is pulled - first the odd numbers then the even ones. This means that when you look at the exposure number, its really only half of what the number really is. If you set it for 2 seconds, it pulls the 1st half after 2 seconds and the second half after another 2 seconds. For my Dark Fields, 10 30 second exposures took 10 minutes instead of 5, because each frame has 2 30 second components. I hope that made sense.
Here are the settings... notice the bug in the software... I had played with the exposure time and it shows 0ms when really its set to 30s. I also have the Gain up all the way to 5.
So my Dark Frames are set and Enabled and finally darkness falls and I get the scope aligned with the new firmware in the StarSense and re-centered and re-aligned and I'm good to go. As I mentioned previously, I put on the MFR-5 to get the widest view possible - mostly to help in target acquisition because I wasn't sure if the firmware update was going to help my poor GoTos.
So here's the setup by the numbers:
80EDT F/6 = 480mm focal length
MFR-5 A (long part)
10mm Spacer
This gave me an approximate effective focal length of (480mm x .8) + 384mm which is F/4.8
Calculating my field of view, I get a whopping 57.90' x 43.25'.
Now I did these calculations tonight, not before, so what you will see now is a collection of objects of different sizes because I chose my objects on the fly versus pre-selecting them. So sorry some of the image scales are quite poor.
I also only had about 90 minutes to play with the images and as you will see below, I am far from adept at changing the settings effectively for a nice image. I also want to say that to the south I have significant light pollution and if you noticed, I'm running without any filters whatsoever. The sky wasn't bad but far from superb as there was a little haze at sunset. So enough blabber and on to the results:
Object #1: M104 the Sombrero Galaxy
So not my best, but hey not my worst either. I've never seen the Sombrero thru my Jr Pro, tho so this is very exciting to me. I dont know why I picked this first. Probably because I was on Spica for Focus refinement and looked for something nearby. This is a 10s image. The gain is a nudge above 1 at 1.20. Contrast taken to +100 to darken it and Gamma up to 1.74. You'll notice no histogram here -- I FORGOT ABOUT IT!! Who knows what this could have looked like... but hey I'm learning. Sorry about the image scale here... its dinky dinky. This is also not the last you'll see of some coma and vignetting. I look back now and wished I'd left off the focal reducer. M104 is Magnitude 9 by the way.
Object #2: M20 The Trifid Nebula
So this is not too bad... I spent quite a lot of time playing with different parameters and trying to only change one at a time. Naturally, whenever you change a parameter, it makes your histogram jump around and so you then have to change the histogram too. So for me, inexperienced at changing settings, there is a lot of experimenting that involves changing a setting + wait + changing histogram + wait + change setting back because it was better before + wait + change histogram back + wait ... etc. etc. you get the idea. Now that seems like a lot of waiting, but its really not that bad. Exposure here was 7 seconds which is a 14 second wait time. It just seems like forever because you're so excited with your new toy.
Object #3: M13 The Great Cluster in Heracles (Greek spelling :-P)
Not my best image of M13, but certainly the best at 10 seconds. I probably spent double the time of all the other objects playing around with the settings. I got a really nice view and lost it because I changes settings and I never got it back. Definitely more time is needed with the sliders. I never got a core that satisfied me even with that better shot... over exposed all the time. I would like to get this out from under the Focal Reduction... I bet I would have a better go at tweaking things out. You'll notice the coma getting real bad. Also tracking was a little jumpy as M13 is almost at the zenith for me right now. So with this shot, I want to point out the sensitivity. Se that smudge NW of M13? I think that is NGC 6207, which is magnitude 11.6. This is a 80mm refractor guys.
Object #4: M101 The Pinwheel Galaxy
Another first for me... I've never gotten the Pinwheel on video and I've tried with my Jr Pro... might not be the Jr's fault most likely mount and bad gotos but still... I went after the Pinwheel because it was to the north and away from the heaviest light pollution. This was a 15s capture with medium gain and gamma centered. I played a lot with gain here and my finding was that I could pull out more detail but it would get awfully grainy. I can get about 4 arms visible here, maybe 5. This one really excited me I must say... I know that there is so much more for me to learn on the settings that I can tease quite a bit more detail here and get the background darker.
At this point it was time to pack up and get to bed for work calls in the morning.
I have some additional thoughts and ramblings that I'll include in Part III tomorrow, so I'll stop here for now. At least I got the images up for you all to see.
--Rick in NWArk
... and so the sun set on our intrepid adventurer and space explorer *ahem* oh yeah back to the review...
Darkness is falling but not quite there, so I go ahead and collect my Dark Frames. I have already put the camera in the scope, so I just leave the scope cap on and take the Dark Frames that way. You can collect the Dark Frames by just leaving the cap on the camera and not have it in the telescope. This is risky to me because if I were to accidentally unplug the USB while putting the camera into the scope, I would lose all of my Dark Frames and the time it takes.
I go with 10 frames of 30 seconds. If I remember right, this is what Chris A. started with and if its good for Chris, its good for me, right? Haha I initially forgot that Dark Frames are also subject to the interlace method of image acquisition so it was slower than I thought. For those of you that are not familiar, these cameras work through what is called interlacing -- think about the image being composed of 582 horizontal lines. With a progressive scan, every line is read until the whole image/chip is pulled. With an interlace scan, every other line is pulled - first the odd numbers then the even ones. This means that when you look at the exposure number, its really only half of what the number really is. If you set it for 2 seconds, it pulls the 1st half after 2 seconds and the second half after another 2 seconds. For my Dark Fields, 10 30 second exposures took 10 minutes instead of 5, because each frame has 2 30 second components. I hope that made sense.
Here are the settings... notice the bug in the software... I had played with the exposure time and it shows 0ms when really its set to 30s. I also have the Gain up all the way to 5.
So my Dark Frames are set and Enabled and finally darkness falls and I get the scope aligned with the new firmware in the StarSense and re-centered and re-aligned and I'm good to go. As I mentioned previously, I put on the MFR-5 to get the widest view possible - mostly to help in target acquisition because I wasn't sure if the firmware update was going to help my poor GoTos.
So here's the setup by the numbers:
80EDT F/6 = 480mm focal length
MFR-5 A (long part)
10mm Spacer
This gave me an approximate effective focal length of (480mm x .8) + 384mm which is F/4.8
Calculating my field of view, I get a whopping 57.90' x 43.25'.
Now I did these calculations tonight, not before, so what you will see now is a collection of objects of different sizes because I chose my objects on the fly versus pre-selecting them. So sorry some of the image scales are quite poor.
I also only had about 90 minutes to play with the images and as you will see below, I am far from adept at changing the settings effectively for a nice image. I also want to say that to the south I have significant light pollution and if you noticed, I'm running without any filters whatsoever. The sky wasn't bad but far from superb as there was a little haze at sunset. So enough blabber and on to the results:
Object #1: M104 the Sombrero Galaxy
So not my best, but hey not my worst either. I've never seen the Sombrero thru my Jr Pro, tho so this is very exciting to me. I dont know why I picked this first. Probably because I was on Spica for Focus refinement and looked for something nearby. This is a 10s image. The gain is a nudge above 1 at 1.20. Contrast taken to +100 to darken it and Gamma up to 1.74. You'll notice no histogram here -- I FORGOT ABOUT IT!! Who knows what this could have looked like... but hey I'm learning. Sorry about the image scale here... its dinky dinky. This is also not the last you'll see of some coma and vignetting. I look back now and wished I'd left off the focal reducer. M104 is Magnitude 9 by the way.
Object #2: M20 The Trifid Nebula
So this is not too bad... I spent quite a lot of time playing with different parameters and trying to only change one at a time. Naturally, whenever you change a parameter, it makes your histogram jump around and so you then have to change the histogram too. So for me, inexperienced at changing settings, there is a lot of experimenting that involves changing a setting + wait + changing histogram + wait + change setting back because it was better before + wait + change histogram back + wait ... etc. etc. you get the idea. Now that seems like a lot of waiting, but its really not that bad. Exposure here was 7 seconds which is a 14 second wait time. It just seems like forever because you're so excited with your new toy.
Object #3: M13 The Great Cluster in Heracles (Greek spelling :-P)
Not my best image of M13, but certainly the best at 10 seconds. I probably spent double the time of all the other objects playing around with the settings. I got a really nice view and lost it because I changes settings and I never got it back. Definitely more time is needed with the sliders. I never got a core that satisfied me even with that better shot... over exposed all the time. I would like to get this out from under the Focal Reduction... I bet I would have a better go at tweaking things out. You'll notice the coma getting real bad. Also tracking was a little jumpy as M13 is almost at the zenith for me right now. So with this shot, I want to point out the sensitivity. Se that smudge NW of M13? I think that is NGC 6207, which is magnitude 11.6. This is a 80mm refractor guys.
Object #4: M101 The Pinwheel Galaxy
Another first for me... I've never gotten the Pinwheel on video and I've tried with my Jr Pro... might not be the Jr's fault most likely mount and bad gotos but still... I went after the Pinwheel because it was to the north and away from the heaviest light pollution. This was a 15s capture with medium gain and gamma centered. I played a lot with gain here and my finding was that I could pull out more detail but it would get awfully grainy. I can get about 4 arms visible here, maybe 5. This one really excited me I must say... I know that there is so much more for me to learn on the settings that I can tease quite a bit more detail here and get the background darker.
At this point it was time to pack up and get to bed for work calls in the morning.
I have some additional thoughts and ramblings that I'll include in Part III tomorrow, so I'll stop here for now. At least I got the images up for you all to see.
--Rick in NWArk