Expert Astrophotography Tips & Discussions | Share Your Photos!

In summary, this thread is for those who are interested in astrophotography. It provides a forum for members to share their expert knowledge with other PF members. It also provides a space for members to share pictures of their astrophotography.
  • #106


mheslep said:
Nice. Can the effects of the recent impact of the Earth size object still be seen on the surface?
It can, but not in that pic. I'm not sure where it is, but I have several other pics from the same night (3 hours ealier and so that covers most of the planet) I haven't processed yet. They aren't as good a quality, but maybe its in them (if it is still prominent).
 
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  • #107


haha
 
  • #108
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  • #109


Denyven, is that even real!?

Astrowesome! :D
 
  • #110


Hello Jupiter! This year Jupiter is going to be a great subject.

Image taken from deep inside the city lights of San Antonio (9-16-09).
Scope is an AstroTech 80ED on an Orion Atlas mount. Camera used was a Phillips webcam (SPC-900NC, WalMart).

It is the best I've gotten out of this small scope... imaged during an public outreach that http://www.sanantonioastronomy.org/" has every cooperative Wednesday night.
 

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  • #111


Mars is about 2 weeks from opposition. Here's my first attempt at it this time around.
 

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  • #112


chemisttree said:
Hello Jupiter! This year Jupiter is going to be a great subject.

Image taken from deep inside the city lights of San Antonio (9-16-09).
Scope is an AstroTech 80ED on an Orion Atlas mount. Camera used was a Phillips webcam (SPC-900NC, WalMart).

It is the best I've gotten out of this small scope... imaged during an public outreach that http://www.sanantonioastronomy.org/" has every cooperative Wednesday night.
Are those stars or Jupiter's moons shown there off of Jupiter's equator?
 
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  • #113


The fact that they are aligned with the equator is a dead giveaway that they are moons.
 
  • #114


russ_watters said:
The fact that they are aligned with the equator is a dead giveaway that they are moons.
Thought so, but I had no idea of the apparent magnitudes expected of stars vs Jupiter moons on that kind of equipment.
 
  • #115


Yeah, you can see the moons easily with binoculars.
 
  • #116


Great shot of Mars, Russ. I've been visually observing for the last couple of weeks with my upgraded (APOgrade) optics in the 80mm using a 7mm T1 Nagler. It is the first time I have been able to see the dark ring around the polar cap that is clearly visible in your shot. I was really jazzed to have finally seen some detail on Mars on my little scope!

I see a lot of older SCT's for sale these days... probably everyone is upgrading to the HD version that has been recently introduced. Good time to be in the market for a used larger SCT, eh?
 
  • #117


Shortly after the snow stopped last Saturday, it cleared up and I shot this image of NGC2903. It's a barred spiral galaxy. This is something like 6 hours of of exposure on Saturday and Monday. The snow tends to make the sky brighter, so I'm pretty pleased it still came out so good.
 

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  • #118


russ_watters said:
Shortly after the snow stopped last Saturday, it cleared up and I shot this image of NGC2903. It's a barred spiral galaxy. This is something like 6 hours of of exposure on Saturday and Monday. The snow tends to make the sky brighter, so I'm pretty pleased it still came out so good.

Excellent Russ! Its a bit like our own galaxy eh?!
 
  • #119


baywax said:
Excellent Russ! Its a bit like our own galaxy eh?!
It looks so much like our galaxy that I wondered, at first, if Russ simply photographed our Milky Way, and was passing it off as another one. :biggrin:

But seriously -- super photo Russ.
 
  • #120


I've often wondered about the stuff like that which is around the galaxy in Russ's photo. Are those stars in our galaxy in the photo or more distant galaxies or both?
 
  • #121


Every sharp point of light is a star in our galaxy, but I also see [probably] three other galaxies in the background. One likely eliptical galaxy is to the right, then two other possible galaxies are center, low. I wasn't able to get the background very flat, so there is a lot of background light in this photo that gets in the way.
 
  • #122


Composite CCD photo I'm guessing. Amazing resolution. What was exposure time per image? Did you use filter?
 
  • #123


Info:
Telescope: C-11 with a .33 focal reducer
Camera: Meade DSI III Pro
Exposures: 8x4min red, 8x6min green/blue, 70x2min and 15x4min luminance
(that's 8 exposures, 6 minutes each, with a red filter, etc...5.5 hours total)
Exposures were stacked in DeepSkyStacker and color mixing and post processing was in Photoshop.
 
  • #124
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  • #125


russ_watters said:
...
(that's 8 exposures, 6 minutes each, with a red filter, etc...5.5 hours total)
Exposures were stacked in DeepSkyStacker and color mixing and post processing was in Photoshop.
So you avoid the any need to autotrack the object by manually readjusting the scope's point over the many hours and then having the software auto-align the different images?
 
  • #126


mheslep said:
So you avoid the any need to autotrack the object by manually readjusting the scope's point over the many hours and then having the software auto-align the different images?
No, my telescope autoguides (there is a secondary scope and camera mounted piggy-back). There are several reasons for multiple short exposures and software-stacking:

1. My mid-level mount's tracking accuracy is borderline for the magnification I'm using. Shorter exposures=less tracking error.
2. My skies aren't very clear and much over about 6 min for luminance would get me a white-out. As it is, the photos come out gray and I have to adjust the color palette in Photoshop (aka, stretching the histogram) to turn the gray black.
3. My skies aren't very still most of the time and the longer the exposure, the less sharp the image. So while a stack of 10 4min luminance images has a higher contrast than a stack of 20 2min exposures, the 2min exposures ended up with quite a bit higher resolution...caveat: they were shot on different nights.
 
  • #127


russ_watters said:
No, my telescope autoguides (there is a secondary scope and camera mounted piggy-back). There are several reasons for multiple short exposures and software-stacking:

1. My mid-level mount's tracking accuracy is borderline for the magnification I'm using. Shorter exposures=less tracking error.
2. My skies aren't very clear and much over about 6 min for luminance would get me a white-out. As it is, the photos come out gray and I have to adjust the color palette in Photoshop (aka, stretching the histogram) to turn the gray black.
3. My skies aren't very still most of the time and the longer the exposure, the less sharp the image. So while a stack of 10 4min luminance images has a higher contrast than a stack of 20 2min exposures, the 2min exposures ended up with quite a bit higher resolution...caveat: they were shot on different nights.
So you do both - your telescope autoguides for short periods and then you post process with software the merges all of the shots into one. Is the autoguiding an open loop correction based on, say, known correction for Earth rotation, or is it a closed loop track on a some target that you designate?

And I forgot: beautiful shot.
 
  • #128


mheslep said:
So you do both - your telescope autoguides for short periods and then you post process with software the merges all of the shots into one.
Yes.
Is the autoguiding an open loop correction based on, say, known correction for Earth rotation, or is it a closed loop track on a some target that you designate?
The telescope mount is motorized and all motorized mounts will passively track at Earth's rotation rate. I wouldn't call that autoguiding, though, since no corrections are made for imperfections in the tracking.

Just about every mount has a sinusoidal tracking error based on the size and shape of the gears and the machining precision (even a thousandth of an inch machining imprecision is very noticeable my photos). On many scopes, that error can be recorded and played-back to subtract it from the tracking to vastly reduce the error. I'd call that an open loop tracking correction scheme. That's not what I use.

I use a completely closed-loop autoguiding scheme, which is what most long-exposure imagers use today. I have a secondary telescope with its own camera piggybacked on top of the primary telescope (it is pictured on the front page of my website...). Software on my computer records the x-y position of a star several times a second, webcam-style, and feeds tracking corrections to the mount to keep the star centered.

Incidentally, somewhere in my system is a bug which is really getting on my nerves. When tracking near the zenith, the alignment of my primary scope to my guide scope starts to diverge, which causes an (apparent) tracking error in my photos. Possible causes:

-Mirror flop (the primary mirror may be flopping back and forth).
-Piggy-back mount flex.
-Guidescope focus tube flex.
-Polar alignment error.
-Main mount flex.

Other aspects of my photography equipment/skills are getting better, which is amplifying this problem, so I'm going to do some serious diagnosis soon...

...And on my Christmas wishlist for next year, an adaptive optics autoguider, which makes these problems irrelevant. Adaptive optics autoguiders steal a bit of light from the main scope and perform normal autoguiding, but add another element: a flat lens that makes finer adjustments in guidance up to 40x a second, vastly improving guiding and even partially counteracting the effects of poor atmospheric conditions.
 
  • #129


Russ, number one (primary mirror shift) is a big one for commercial cats and I don't know of a reasonable way out of it, apart from avoiding zenith, rotating the 'scope around the declination axis, and resuming a bit later after the field is at least a few degrees past zenith. A close friend of mine had this problem with an otherwise well-built orange C-8 with an off-axis guider. Of course this was during film-only years in which you couldn't discard errors and combine the good stuff, so he was tearing his hair out. I had a very minor problem with differential flexure, which I solved by finding the balance point of my guide-scope, and mounting that balance-point exactly between the mounting rings, PLUS checking for alignment of the guide-scope as the temperatures changed, and re-tightening the thumb-screws in the mounting rings to help account for shifts due to thermal expansion/contraction.

Suggestion: Put a high-power EP in both the main scope and the guide-scope and align them on an appropriate star to within a frog's hair (you might need to borrow an illuminated-reticle guide EP from a friend if you don't have 2 of them). Once you have the two OTAs aligned perfectly, flip the whole system in DEC and pick out another star to compare alignment. Got shift? It's probably primary mirror mis-alignment.
 
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  • #130


Thanks, turbo. I was going to try something like that to narrow down the error. What makes it seem less likely to be mirror shift to me is just how regular the excess motion it. Anyway, If I can isolate the problem (heck, even if I can't), there are 3rd party mirror locks I can buy and install.

...I also have an off-axis guider I haven't tried yet.
 
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  • #131


Hey Russ,

Sorry to barge in, I just met this kid that told me all about his digital telescope. He has it hooked up to his apple laptop and can punch in a topic like the Apollo 11 landing site and it will give him coordinates which I guess he enters and the telescope moves. Then the images are direct to his laptop. That's pretty cool but I wondered what you think about that strategy(?)
 
  • #132


baywax said:
Hey Russ,

Sorry to barge in, I just met this kid that told me all about his digital telescope. He has it hooked up to his apple laptop and can punch in a topic like the Apollo 11 landing site and it will give him coordinates which I guess he enters and the telescope moves. Then the images are direct to his laptop. That's pretty cool but I wondered what you think about that strategy(?)
I can do essentially that and it is kinda cool, but it is more trouble than it is worth. The telescope already has its own hand controller with an object database. Just type in the name or catalog number or scroll through a list and hit enter.

All of my photography is done via the computer.

...what my telescope won't do without a computer is track satellites, so I'm going to have to give direct laptop control a shot to take pictures of the ISS. That's even worse because while the software I use, Starry Night, will make my scope go-to an object just by pointing and clicking, it won't do satellite tracking. I have to find a different piece of software for that.
 
  • #133


russ_watters said:
I can do essentially that and it is kinda cool, but it is more trouble than it is worth. The telescope already has its own hand controller with an object database. Just type in the name or catalog number or scroll through a list and hit enter.

All of my photography is done via the computer.

...what my telescope won't do without a computer is track satellites, so I'm going to have to give direct laptop control a shot to take pictures of the ISS. That's even worse because while the software I use, Starry Night, will make my scope go-to an object just by pointing and clicking, it won't do satellite tracking. I have to find a different piece of software for that.

That's amazing Russ, thank you.

One more question for you... sorry!

I asked the kid if he could see the leftover bits of the Apollo landing and he said no. This guy, who is about 10, said "you can't see those but there are blurs that seem unnatural to the rest of the terrain. Now, I understand that its going to take a very high powered telescope to see what's left of the lunar module or the flag etc... but, I still don't understand why its so difficult to hone in on this kind of detail. You may have clarified this before, but I'm still fuzzy on it.:redface:
 
  • #134


Here are a couple of Saturn I took the other night..I tried stacking a group of about 30 images similar to this, but it came out worse than the individual pictures themselves..am I doing something wrong with Registax or do I need better equipment? At any rate, these are the two best images I could get of the planet, considering the rings are edge on :(
 

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  • #135


I did a Registax tutorial that may help: http://www.russsscope.net/staxtutorial.htm

My guess would be you need to play with the wavelet sliders (step 6). Also, if you are using a webcam, try shooting a lot more pictures. Also, make sure they are high quality files (bmp or uncompressed avi, not jpg or mpeg).

What kind of telescope and camera are you using?
 
  • #136


Well, I think Registax is having trouble aligning the images. I'm only using a 6" inch dobsonian (around 200x magnification) and a digital camera, but I've been able to take a lot of pictures like the ones above. I'm assuming those are good enough for Registax to recognize, even though those are a bit enhanced with my limited photoshop skills. Even with 30 or 40 images of similar quality, its saying a lot of them are low quality and not aligning properly. I just recently started trying stacking pictures, so I plan on getting a webcam within a week or so. Also, I tried stacking images of the moon, but I can't seem to get the alignbox big enough to fit the whole moon. I tried using the customized alignbox setting, but there is some error which brings the size back down to 256 after I type in the number. I may be overreaching a bit, but I'm pretty much addicted to my telescope so its just a matter of time before I upgrade to something I'm sure will take the pictures I want :)
 
  • #137


A webcam will be a big help. It's tough with a regular digital camera.
 
  • #138


For an afocal image of Saturn, your photo is pretty good! You can see the thin line of the rings across the face of the planet which no small thing for it being that low in the sky. There is a little atmospheric refraction (red edge/blue edge) so I assume that you took the pics when it was low in the sky?

What kind of camera and scope/eyepiece did you use?

On the Moon, you can align in Registrax using a crater with good contrast most of the time.
 
  • #139


FYI, the first pic was my first ever astrophoto with a Quickcam and a crappy 60mm (2.4") refractor. The second pic was taken with a 104mm (4.1") Mak-Cas and the Quickcam.

Notice the dates on the pics...that's the big problem, when you light the fire you need more...
 

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  • #140


is 35mm film still a viable option for Astrophotography?
 

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