Getting into astrophotography

**Neezer** · 09-28-2009, 08:38 PM

Got another moon shot...

shutter: 1/640
ISO: 800
F:5.6
300mm

I think the bottom is a touch over-exposed...I had to darken it a bit in photoshop.

**Fuzz** · 10-03-2009, 09:07 AM

Was able to get up to 30-sec exposures today (thanks to some tips from some more experienced astronomers). With the almost-full moon up tonight, Orion was the only realistic target. The 30-sec exposures really brought out a ton of spectacular detail.

8 x 30-sec subs:

**Lonnie** · 10-03-2009, 05:33 PM

I am at a crappy hotel terminal, so no uploading, and it's not astrophotography per se, but I got some AMAZING night time shots a arches national park under an almost full moon the other night. I can't wait to share them with the collective.....

**Neezer** · 10-04-2009, 04:43 AM

Fuzz,

Is that taken with a web cam or a dslr with the telescope as the lens? also, if you have 8x30 second exposure, does your software stack them so that it matches the light?? what I'm getting at is the lack of an equatorial mount...I assume the 30 seconds is about as long as you can get before you get star trails...so just plain stacking would create trails as well unless in the software is shifted each successive picture by just a touch so that all the points of light match up.

I hope that question makes sense, if not let me know and I'll try to ask it differently.

**Fuzz** · 10-04-2009, 08:22 AM

Originally Posted by Neezer

Is that taken with a web cam or a dslr with the telescope as the lens? also, if you have 8x30 second exposure, does your software stack them so that it matches the light?? what I'm getting at is the lack of an equatorial mount...I assume the 30 seconds is about as long as you can get before you get star trails...so just plain stacking would create trails as well unless in the software is shifted each successive picture by just a touch so that all the points of light match up.

It was taken with a DSLR (Canon 40D) prime focus on the telescope (i.e. body attached directly to scope). The telescope is on its standard alt-az mount, which sucks for accurate long-exposure tracking -- especially with the extra weight of the camera, which throws off the balance. To improve tracking for photography, based on a tip from FRAC, I did my initial alignment with the camera attached. So the scope basically "learned" to align and track with the extra weight at the back, allowing it to track steadily for at least 30 seconds. So technically, each shot should exactly be the same -- in reality though, the scene does shift from one frame to the next.

All stacking software takes care of the two basic types of movements between individual frames in astrophotography: translation and rotation. Translation is when the stars are simply offset in one direction from one frame to the next -- the simplest example is if you are shooting the a close-up of the moon on a static tripod, it moves across the field of view in a straight line. The stacking software can figure out the offset and align them correctly. Rotation is when objects rotate around in the field of view. In a wide-field shot (static on tripod), the sky rotates (around Polaris) from one frame to the next. Stacking software can also figure out the rotation and adjust for that.

DeepSkyStacker automatically figures out whether you have translation and/or rotation in your frames and corrects for them. If you don't like the auto results, I think you can also manually select a star in each frame to let DSS know where that same star is located in each frame.

So when I ran my frames through DSS, as part of the stacking process, it automatically figured out when there are was translation and/or rotation, and lined them up.

Note that this last Orion shot is actually a composite of two separate stacked images. 30-second exposures of Orion capture the great nebulosity, but completely blows out the central core. So I took another image which was a stack of 2-second exposures (which captures the central core well but shows little/no nebulosity), and blended it with the 30-sec stack to get a balance of both central core and nebulosity.

While I am happy with my attempts so far, to give an idea of how pathetic my images really are, here's a "real" astrophotograph of the whole Orion Molecular Complex (the Orion Nebula is in the upper right corner) taken by an amateur astronomer using proper equipment (equatorial mount, CCD camera). At the bottom of each image, you can find the technical details of each.

**Fuzz** · 10-04-2009, 08:23 AM

Originally Posted by Lonnie

I am at a crappy hotel terminal, so no uploading, and it's not astrophotography per se, but I got some AMAZING night time shots a arches national park under an almost full moon the other night. I can't wait to share them with the collective.....

If it has stars, it's astrophotography; doesn't have to be with a telescope. Looking forward to it. Next time we go to Moab, I am definitely bringing my telescope since the surrounding areas have very dark skies.

**pointedem** · 10-04-2009, 04:49 PM

Per the above definition, here are three from the other night

Alta, Utah.

**Fuzz** · 10-04-2009, 05:06 PM

^^^ Nice! Time of day? The second shot is particularly interesting -- how did you get the long exposure to create star trails but not overexpose the snow?

**pointedem** · 10-04-2009, 05:45 PM

11p-3a ish. Good question. It wasn't blown in the histogram, but I did pull the highlights off just a touch.

From memory:

iso 200
~280 seconds
f/5
no EC

**Tunco** · 10-04-2009, 05:56 PM

Glad I found this thread. Keep it coming. Please.

**Fuzz** · 10-04-2009, 07:49 PM

Originally Posted by pointedem

11p-3a ish. Good question. It wasn't blown in the histogram, but I did pull the highlights off just a touch.

Thanks for the info. When I was shooting that last Orion shot this weekend, the almost-full moon was up and created a very nice light on the mountains. Wanted to take some "regular" shots, but since there was only an hour and half of darkness left before sunrise, ended up focusing on Orion only. Will have to try it the next full moon (and clear skies).

Here's a prime focus shot of the moon I took the evening before (was testing the focus before shooting Orion):

**Neezer** · 10-04-2009, 08:04 PM

Great shots Point! I really like the third one.

Fuzz, what is the focal length of your telescope? If I understand correctly, higher focal length = more magnification? What is the resolution of your camera? I am assuming that you resized your image to fit it on the page here....I guess what I'm getting at here is the possibility of a poster sized photo of the moon.

**pointedem** · 10-04-2009, 08:22 PM

that's pretty nasty fuzz.

**Fuzz** · 10-05-2009, 09:30 AM

Originally Posted by Neezer

Fuzz, what is the focal length of your telescope? If I understand correctly, higher focal length = more magnification? What is the resolution of your camera? I am assuming that you resized your image to fit it on the page here....I guess what I'm getting at here is the possibility of a poster sized photo of the moon.

Focal length = 2000mm. So essentially it is a 2000mm lens (at zero magnification -- visual observations are done at 80x - 200x). Camera is a Canon40D, which is 10MP (3888 x 2592). At prime focus I cannot get the moon in a single frame -- would have to create a mosaic. So yes, poster-size prints are a definite possibility.

The trick in printing will be to get the right settings to capture all the details. I printed an 8x10 of Orion on my home photo printer (HP Photosmart D7460) and the edges of the nebula didn't show up. The printer is good at photos and regular shots come out fine, but the faint light of the nebula is beyond it (with default settings at least).

**Lonnie** · 10-05-2009, 11:04 PM

Hope you like. I have several more, that are better than this, that I'll show later....

**Fuzz** · 10-06-2009, 07:48 AM

Originally Posted by Lonnie

Hope you like.

Like. Just a couple of comments: seems like the image is compressed quite a bit - lot of JPEG artifacts especially in the sky, making it hard to see the stars well - do you have a version on PhotoBucket or Flickr? You could make a great composite image if you had a shot exposed for the moon only.

More please.

**Lonnie** · 10-06-2009, 08:56 AM

Here is a re-do and a couple others...

**Fuzz** · 10-06-2009, 09:04 AM

^^^ Damn, that last one is a poster-worthy shot for sure!! Not that the other ones are bad, but I love the colors in the last one, plus the Big Dipper is positioned so nicely.

**Fuzz** · 10-07-2009, 03:07 PM

Andromeda Galaxy (M31) from last night (30 x 30-sec lights (only 18 usable), 15 x 30-sec darks).

Looks like there's more detail but just can seem to figure out a way to tease them out.

**HellgateBasement** · 01-29-2010, 06:09 PM

Brightest moon of the year tonight so I'm thinking about messing around with the camera.

What would be the best way to shoot the setting moon with a barn in the foreground?

I'm a total jong, shooting with a D50 and a 75-300 lens.

**pointedem** · 01-29-2010, 06:20 PM

make sure the moon light is on the subject you want to photograph-- ie make sure the barn isn't in the shadow or u'll have a bitch of a time getting the exposure right. Try 800 iso if ur shooting with that 75-300. I think that starts @ F4.5 on the short end- 800 and f4.5, 30 seconds, in full moon should be bright enough. good luck- half the fun is experimenting with it.

**Fuzz** · 01-29-2010, 08:33 PM

If you want to get a full moon + something else in the same image, you'll have to create a composite. The full moon is very bright, and you'll need about 1/320 or faster shutter speed to properly expose it. At that speed, everything else will be completely dark. You'll have to shoot the barn separately with a longer exposure (which will wash out the moon) and combine the two shots.

**HellgateBasement** · 01-29-2010, 09:28 PM

Pointedem - thanks for the specifics. You're right about the lens. I'll start with those settings and see how it goes.

Fuzz - I'm clueless about the composite. I take two shots without moving the camera, different exposures, and then photochop them?

Or two completely different compositions and photochop that. Seems like cheating. I see what you're saying about everything else being too dark though. In theory, if I had external lights on the barn, that would get it done?

**Fuzz** · 01-29-2010, 09:52 PM

Originally Posted by HellgateBasement

Fuzz - I'm clueless about the composite. I take two shots without moving the camera, different exposures, and then photochop them?

Or two completely different compositions and photochop that. Seems like cheating. I see what you're saying about everything else being too dark though. In theory, if I had external lights on the barn, that would get it done?

The former -- one shot with a fast shutter for the moon, a second shot with a slower shutter for the barn. Then replace the washed-out moon from the longer exposure with the moon from the short-exposure shot. You could avoid having to create a composite by lighting up the barn. Or if you shot the barn with the moon behind you, but I think that defeats what you're trying to shoot (both moon and barn in one image).

Look at this shot Lonnie posted:

Originally Posted by Lonnie

You can see the foreground is exposed very well, but the moon is completely overexposed.