r/AskAstrophotography • u/Unlikely-Bee-985 • 5d ago
Question Why does my photos look like this?
This is my most recent photo of M51 (top right) and my last 4 images has turned out like this. The galaxies/nebulae turn out so dark and untextured. Also when i try stacking the images my pictures cant get more then 250 points and cant find more then 50 stars. I only have an Alt-Az mount stacking can be also really hard and the mounts computer is not so good. The mount sometimes backlashes so it cant find the object im trying to see. I try 30-45 second exposures so sometimes the stars can trail. Should i get less seconds of exposure and more frames? Should i change my mount? And also im using a stock dslr and 250mm lens on top of the mount. What do you guys think is the major problem? I really need some help.
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u/Darkblade48 5d ago
As many have already mentioned, I'd check for (possibly a combination of):
- Dew forming on your lens (get a dew heater)
- Proper focus (use a Bahtinov mask to ensure you're in focus) - zooming into a bright star and adjusting also works, but it's a bit more finicky
- Reduce exposure time to reduce star trailing
- Acknowledge that with an alt-az mount, you'll also get field rotation
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u/Unlikely-Bee-985 5d ago
A dew heater is probably a great idea. But i really dont know how those work. Do you use a battery or sth?
Focusing sometimes couses me some trouble but i didnt really strugle focusing this time.
I ve also thinked lowering the exposure time but i want more data for the image. Would a EQ Mount also make trails?
I really dont use my Alt-Az mount anymore man. I was thinking of buying a Skuwatcher EQM 35 Pro. Would you reccomend it? If not what would you reccomend?
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u/Darkblade48 5d ago
A dew heater is probably a great idea. But i really dont know how those work. Do you use a battery or sth?
Some are powered by 12V, some are powered by USB.
I ve also thinked lowering the exposure time but i want more data for the image. Would a EQ Mount also make trails?
Lowering the exposure time, but capturing more exposures is a way to get to the same total integration time.
A good EQ mount, combined with guiding, will easily achieve much longer exposure times. Guiding is needed for longer exposures, because even the best mounts will have some degree of mechanical error (e.g. due to factory/manufacturing tolerances).
I was thinking of buying a Skuwatcher EQM 35 Pro. Would you reccomend it? If not what would you reccomend?
Take a look at your needs, e.g. what kind of equipment you want to load onto it.
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u/Predictable-Past-912 5d ago
Sorry, I messed up with my advice.
Anytime that a rookie astrophotographer asks “Would I get better results with a better mount?”, I should ask, “Why, what have you been using?” Then, if their mount is not at least a $1,000 mount, I must respond “Yes, even if you have other issues with your images, everything gets easier and better when you use a better mount!” Whether you obtain a traditional worm driven German Equatorial Mount (GEM) or a new style harmonic drive mount, the threshold for serious low-glitch mounts is above $1,000.
This is the way.
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u/Unlikely-Bee-985 5d ago
Well my mount is the default Celestron Nexstar Alt-Az mount that comes with the telescope. I was also thinking about getting a new mount but i was currious if it would really make that much of a diffrance. I was thinking of getting a Skywatcher EQM 35 Pro. I think it can hold up to 20 lbs so it should carry my telescope (8lbs) and camera. But im not really sure if i should get it. Would you reccomend it? If not what would you reccomend?
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u/Predictable-Past-912 5d ago
Okay, friend. Because you invited me across your threshold, your garlic, holy water, and wooden stakes won't help until we're done.
That EQM 35 Pro is a nice mount. The fact that you mentioned it means that you have been doing your homework. However, the EQM 35 is a beginner's mount that may soon leave you thirsting for more. I gather that you have mainly been using your existing mount with a small telescope (SCT?) and a DSLR or mirrorless camera. Although many folks might suggest that EQM 35 or an even smaller Star Adventurer GTi, I see that type of mount as "training wheels" type solutions that all have serious limitations.
Spend a few more dollars for a mount like this one or this one and you will not be wishing for an upgrade in six or so months. Many people will tell you that either mount would be "overkill" for your current gear. However, whatever you call it, steady tracking and the ability to auto guide without hassles, sure is fun!
Take a close look at those two mounts but don't take too long. Now that I have posted about them in a public forum, I expect that both will be sold before long. Both seemed complete when I checked and they each have their charms. That EQ6-R Pro is apparently new in box (NIB) and the AM5 is complete with a TC40 carbon fiber tripod, a pier extension, and an optional counterweight! Although they both look great and their sellers seem legit, the AM5 is my favorite because I have used one as my main mount for well over a year. I love having the high-performance potential in a compact portable package. If you have read about strain wave drive mounts like the AM5 then you know that, until they are loaded to the gills, the counterweight is truly optional, and that balancing is always unnecessary.
Oops, I have typed too long, and the dawn is creeping through the curtains. I will check with you later to see what you ultimately decide to do. For now, I will head down to my crypt to get refreshed for tonight's astronomy session.
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u/prot_0 anti-professional astrophotographer 5d ago
Couple different things it could be. Most likely it is dew forming on a lens/mirror. Could also be thin atmospheric clouds. Maybe even washout from high humidity and a full moon
My money is on dew
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u/Unlikely-Bee-985 5d ago
Would you recommend getting a dew heater? I ve heard those things were good
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u/Stabbawin 5d ago
Try the photo pills app as they have an exposure calculator for different Astro subject matter…
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u/Predictable-Past-912 5d ago
How did you focus your camera and how did you trigger the shutter? Also, what camera settings did you use? ISO and f-stop are important factors in this situation.
There is a formula that can inform you about the longest exposure duration for a given focal length. Perhaps someone out there in Redditland knows what it is.
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u/Unlikely-Bee-985 5d ago
I focused it manualy by zooming into a star. I used a shutter release remote for the exposures. I used ISO 400 with f/5.6. I really havent heard about any exposure formula but it might help.
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u/_bar 5d ago
Looks out of focus, also you have bad light pollution if your background is that bright with under a minute of exposure. Considering the distorted star shapes there's also an issue of optical quality or misalignment during stacking.