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crovax

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Everything posted by crovax

  1. Uh, well, I've created a median layer but after all the noise didn't go away. I believe that I may have messed up something when taking the photos so I am planning to redo everything from the start. However before I do this, could you please let me know whether the following procedure is correct: take X subs, take X darks, average darks into master dark, subtract master dark from each sub, merge subs using "addition". If I am mistaken here, please correct me. Also I am not sure whether there is some difference when I "subtract" master dark from sub or when use "difference" mode. And the final place where I have doubts is ISO. I've been playing with ISO 1600 but I wonder whether this is too extreme or not?
  2. Oh, never mind, I guess I found the median tool in photoshop. It's located in layer -> smart objects -> stack mode -> median
  3. Hi, Thanks for the awesome explanations! I've already took all the darks and now I am trying to create a master dark of them. Unfortunately I got stuck at this point. It seems GIMP doesn't have this feature (or it is named in a way that I can't recognize it). I found a plugin that is supposed to do this but it is very buggy and I can't get the results out of it. I also tried looking in DSS and Photoshop but still no luck. Could you give me link to Maxim software you mentioned earlier. Also do you by chance know Linux software that can average/median images? My main and the most powerful PC is running Linux and I feel lazy about installing virtual Windows on it. However if this operation is not very resource hungry I can always perform it on one of my old computers that run Windows.
  4. Ohh, that makes sense now! Just to clarify things, "master dark" is the resulting image that we get after combining our X dark frame shots, right? Also I don't understand very well what master bias is and what "subs, plus flats" are? I read about nature of bias noise and article suggests taking shots with 0 sec exposure. I doubt I can do this since my camera is not a pro one, it's a simple canon powershot a580. Is it possible to go with master dark only since as far as I understand it contains bias noise (as well as dark noise)? Or are the bias 0 sec shots a must?
  5. Hi, I've recently went through a wonderful article on afocal astrophotography (Afocal Astrophotography) and decided to try to use the theory I've learned. Well, since I haven't seen clear skies for months already my test object is a book in a dark room. All the photos below are ISO 1600, and 4 sec exposure. I decided to go with 1600 because I thought this would give me very noticeable noise and therefore very noticeable results of dark frame technique. The exposure is 4 sec because I wasn't able to make the room any darker First I took 5 photos of the object. Then I took a dark frame photo. So far so good. Then I went to PC, opened GIMP and put all the 6 images on different layers. For the first 5 I used "Addition" mode and the result is quite expected. And then I tried to use "Difference" mode for the dark frame. I also tried "Subtract" but these two different modes produce result that look the same so I decided to stick with "Difference". And that's the place where I get the unexpected result. I sort of hoped that all the horrible noise from the photo will be gone but this didn't happen. The photo changed a little but I can't tell whether it became better or worse. I've uploaded all my result here Picasa Web Albums - eugene.bondarenko - testing... If you hit "Download" you can get any image in the original size. Could you please tell me what I am doing wrong. Is it because of big ISO? And if yes, how is this noise called and is it unremovable? On the other hand if this is Dark Current Noise after all, then why didn't it get removed after I subtracted the dark frame? Or did I subtracted it in a wrong way? Or is the result not noticeable because I stacked only 5 frames and if I had stacked 100 photos, it would have been noticeable? Uh...sorry for so many questions
  6. I am very surprised with your SNP issues. I have ASUS EEE 900 which has quite weak specs and a weird screen resolution. No problems so far. Except that some big sized info doesn't fit into the tiny display and gets cut off.
  7. I wear glasses but I take them off when I use binos or telescope. I simply find it very uncomfortable to wear glasses and look through EP/binos. On the other hand as JimBobs63 has mentioned another observer will have to refocus after you. And then you'll need to refocuse after that observer. And so on. Also every time I look at the sky to point my 'scope to the right place or to navigate through stars and constellations to find the right place to point 'scope at, I have to put my glasses, then take them off to look into EP, then put them on to point 'scope again, etc. This s*cks very much too. I think that alfi is right, simply try both and you'll know which is more comfortable for you.
  8. Judging from your picture Jupiter looks quite nice and the size is fine. Most likely the Barlow didn't help because the turbulence was bad. In such cases big magnification usually gives a disgusting smudge instead of Jupiter However you should definitely try 10mm+Barlow again. Jupiter is an mazing target for large magnifications. I've been observing it with 4mm and 6.5mm+Barlow and it is totally worth it. On 6.5mm+Barlow I even started seeing features in the bands (instead of seeing them as lines).
  9. Hi, I think you're having the problems because of bad focus. I (at last!) observed sunspots this Saturday with my 130 skywatcher. I tried playing with focus (using 25mm EP) and sunspots simply become invisible if the telescope is not focused perfectly. Try using the following trick. Set up your 'scope, locate a distant tree, focus on it, put on your filter, locate Sun and look into the EP.
  10. Thanks, I also hope that the weather will be nice. Right now all the sky is fully covered with clouds and taking into consideration the current season, the sun can be hidden for weeks now. July sunspots were very disappointing. They disappeared exactly on Saturday
  11. Ohhh and again I am missing the sunspot because it is up during the wordays :( What do you think about the lifetime of this spot? Will it last till weekend?
  12. I dunno, next weekend I'll do my best to find this object again. I guess this won't be very hard because it was a very noticable thing. Not veeeery noticable like Vega but still not a tiny star. IMHO it's impossible to miss it. Then I'll be studying star patterns and making photos and hopefully will get its name. The problem is that I don't clearly see Pisces. I can try to start tracking the object from Aquaris but it is not very helpful too. Only Phi Aquarii is a little close to that area and that star is not much brighter than the stars from Pisces.
  13. This is totally weird, this reddish star was so distinguishable that I was sure it was not a star. This brings back the quest of finding Uranus Also I'll do my best to accurately locate this thing and then will be sketching it to determine if it moves or not. Or even better - I'll be making potos of it.
  14. Well, if no one comes with an idea about this thing untill next weekend, I'll make a photo of this UFO and post it in this thread
  15. Well, that raises another question: what was that? I saw blinking stars caused by air turbulence and this is definitely not the case. It was stable and red. Just like Mars.
  16. Well, after seeing Neptune I didn't expect to find Uranus. I found Neptune only because it was very close to Jupiter and it looked exactly like a tiny star. Anyway I gave Uranus a try: studied star pattern, found what I believe was Pisces (hate these faint constellations), pointed my quickfinder to the location and saw a strange object. It was a like a not very faint star...but omg it was colored red. I've never seen red stars before so I believe it was Uranus....but shouldn't this planet be colored in blue colors?
  17. In Starry Night this can be found under View -> Constellations. You can also select Asterisms (which is probably useful only when you are starting to lean sky), Zodiac (no fun becuase this shows very small amount of constellations), Oriental Moons Stations (this is a mystery, I don't have any idea what are those Black Tortoises And White Tigers it shows).
  18. The problem with Scutum is the amount of M-objects located near it. That's the only reason I went for it. Well, also I wanted to get known with one more constellation but the main goal were Ms. I am located in Ukraine (not UK) but still Scutum is very low. I can clearly see all the Aquila but everything that is below is very hard to see. I've been waiting for a Moonless night and if the weather is fine this weekend I'll give Scutum another try. I am observing from country house (so I have low light pollution) and moonless nights are just amazing. The problem is that I totally forgot about Scutum the last Moonless night. I was amazed that I can see Andromeda, Double Cluster and millions of stars with just naked eyes. Also Perseids were still falling down leaving awesome trails behind them. This all kept me occupied and somehow I forgout about dim constellations. However this time I placed a reminder in the phone and I definitely won't forget about it. If I won't be able to see it even in such conditiond, I guess I'll give up and will have to search those Ms starting from the bottom of Aquilla. By the way I've found another fun that you can go for when you know all the constellations. In Starry Night (and may be in Stellarium) you can set different types of constellations. I've been learning "Astronomical" ones. But when I set "Reyhs", I found out that some of them look funnier. So in Astronomical version Hercules looks like a square with 4 lines (which are probably legs and arms) going from corners. And in Reyhs this constellation looks like a guy with a club. And Reyhs Perseus looks like a man in triangle hat which is more nice then astronomical version. So now I am learning alternative versions of known constellations.
  19. I surprisingly found that experience in finding constellations really matters. Several moths ago I knew only one constellation - Big Dipper. I started learning skies and it was veeeery hard to find anything. I have dark skies too so I understand you quite well. I struggled much to find my first constellations. But then it was getting better and better and better. I still don't know all the constelltions but now when I want to find a new constellations it tooks around 15 seconds to get it - I look at starry night (analogue of stellarium), then at sky and the stars combine into constellation. Unfortunately right now I am limited by my not very strong eyes and I am struggling with dim constellations like Scutum. I remember that when got lost in all these numerous stars I decided to base on stars. Try looking at the whole night sky and check the brightest stars. Then check stellarium and find their names. Those will be Arcturus (now look above it and you'll see Bootes constellation). Then check other 3 big stars forming a huge triangle over your head. Thouse are Vega, Altair and Deneb. Each of these stars are in a constellation which you can try to find. When you have cleared all the bright stars you can try finding the rest basing on what you already know. Like finding Hercules which lies on the line joining Vega and Arcturus. Have fun and clear skies!
  20. Or he can make the animation of moon going full and then disappearing back. Anyway whatever it is I can't wait to see the results.
  21. Thanks for your help! Unfortunately the lowest exposure I can get is 1sec so I guess no Jupiter for me. I'll concentrate on DSOs then. Yeah, that smudge is one of the moons. It appears like that because I haven't perfectly polar aligned the scope. That was a quick test only and I was not after super great images that night.
  22. I have a similar problem. I have Canon PowerShot A580 and rings that I use for attaching the camera to my EP. I've tried making photos of the Moon and Double Cluster and the images are fine. Well, they still suck much because I'll need to go through at least several manuals before I will show my images here. But at least I can see some details on the photos - stars in the Cluster and Moon features. Then I continued my experiment and pointed telescope at Jupiter. And it surprised me a lot. No matter what ISO and exposure I used the result was almost identical - a very bright spot. Well, the brightness varied when I was changing ISO and exposure but even at ISO=80 and exposure=1sec (the lowest for my camera) I was getting something that can never be recognized as a planet. To give you a better idea of my issue, I attach a photo. I don't remember the exact ISO-exposure settings for this photo. I have dozens of these nice white circles and, trust me, they don't vary much from ISO=80 to ISO=1600. So....what am I doing wrong?
  23. Oh, I absolutely forgot to return here and thank everyone for quickfinder advice. It's pure awesomness. Now I can't even hold in my head all the objects I usually find per session I already saw M57 and many many other stuff
  24. Yes, I agree about Andromeda but Andromeda is very hard too miss and what's really important it gives you idea about how galaxies look like. I am still a big newb so I remember the first time when I was after DSOs. It's really hard becuase you don't know how it is going to look like and how small it is. Also IMHO Andromeda's sattelite galaxies are a great chance to check how faint galaxies look like. By the way I finally purcased and already received quickfinder so I'll be after M81&M82 this weekend too. That will be a good test for ir.
  25. Judging from my experience with M51, the main mistakes are looking for such things when the full moon is up and not spending enough time on studying the area you see. Just put in 25mm and then very slowly scan the area where you target should be: point at area, carefully look at it for 5 seconds, point at the next area etc.. If you do it that way, you'll definitely find it. When I saw a distant galaxy for the first time it looked like some anomaly on sky: "dark sky, tiny stars and...wait, what's this strange a little less dark area of sky." Later after using the method "the more time you look the more you see", I was able to much clearly see this galaxy and even see that these are two galaxies actually. So don't give up, you'll definitely find M81/M82! It just requires some time especially when doing this for the first time. Good luck and clear skies!
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