If anyone wishes to contact me with questions, comments, etc, my email is russ_watters@lycos.com.

January 31, 2010: Long Time Since Last Update

Last winter I got a new DMK31AU03 planetary camera. I've taken some pretty good photos of Jupiter, Saturn and Mars. I also have a few new galaxy photos in the past year, the best being a M-31. For Christmas this year, Santa got me a DSI III Pro, but I haven't had a chance to use it yet. Stay tuned!

March 23, 2008: Tough Year Weather-Wise

Winter is usually the best time for Astrophotography. This year wasn't so good. It seemed like it was usually clear during the day, then cloudy at night. I only got three decent pictures since the fall, though I was quite happy with the ones I got.

Last month, I stripped-down my mount, cleaned, and regreased it. I found one of the bearings rusty due to a lack of grease, and found a replacement for it. I also replaced the mount's dovetail bracket (which holds the telescope) with a sturdier, less wobbly-one. I'm not really sure if these changes made an improvement in the tracking, since I've only been able to test once and I'm not sure I had a good polar alignment.

February 14, 2007: A Brief Lesson in Imaging Techniques:

The Setup - Initial Setup:
For deep-sky images, long exposures must be taken to gather a lot of light. Long exposures require very precise tracking of the telescope to keep the object from moving around and smearing the image. The first requirement of good guidance is a good initial setup and alignment. Care must be taken to have the mount precisely leveled, balanced (I use forty pounds of counterweights!), and aligned with the Earth's polar axis. Alignment is tricky - the north star (Polaris) is actually close to a degree off the polar axis. My telescope has a polar axis alignment scope in the middle of the mount (the polar axis shaft is hollow), with markings for finding the exact position of the polar axis with respect to Polaris. But that can only get you to within a few tenths of a degree and that still isn't good enough. Careful tracking of the motion of stars (there are several procedures for this, and I'll spare you the details for now...) allows for finer alignment. But even with a good alignment, tracking isn't perfect...

No telescope can track perfectly on its own. Besides alignment errors, tiny imperfections in the gears - thousandths of an inch - show up as periodic error patterns in the images - the image will move back and forth on the screen in a repeating pattern. For my old telescope, half of my images of 30 seconds would be unusable and I couldn't go any longer than that. With my new telescope, I can keep most of the images up to a minute exposure. But that still isn't good enough. For longer exposures, automatic guidance is required. I recently started autoguiding with my my old-old telescope as a guide-scope. A camera is connected to my laptop, which is connected to the mount. The laptop tracks a star near the object to be photographed and sends commands to the mount to keep the star centered. With this technique, exposures of any length can be taken, though things like wind or vibrations in the mount due to an unstable location (such as my deck) can still spoil an image.

Acquisition - The Camera:
I primarily use the Meade Deep Sky Imager II Pro. It connects to my laptop, webcam style, and mounts directly on the back of the telescope, with no lenses in it and no eyepiece on the telescope. The DSI II Pro is a monochrome (black and white) camera. To get color pictures with it, I shoot separate images through filters for each color (red, green, and blue) and combine them later in software. If you see "rgb" under an image on my site, it was taken with this technique. Additional detail can be gathered by a black and white image, which pulls in more light because there are no filters to block some colors. This is called a luminance (brightness) frame. Images taken with this technique and combined with rgb photos later in software are labeled "lrgb" in my gallery.

There is noise in all cameras. A ccd camera works by converting light to electricity, and that generates heat - which converts more charge to electricity and shows up in the pictures. This noise is very predictable and is automatically subtracted out of the initial acquisitions by taking "dark" frames. Dark frames are literally what they sound like - the telescope is covered and images of nothing are taken, equal in length to the images to be taken of objects later. Since the noise repeats, it can simply be subtracted out. Unfortunately, this noise is temperature dependent, so when the outside temperature changes by more than about 5 degrees, new dark frames need to be taken.

Pre-Processing - Stacking:
All images have a certain signal-to-noise ratio. The noise is the grainyness you see in some regular photos, as well as atmospheric distortions of the light rays (like the wavyness you see in the distance on the road on a hot day). In astrophotos, due to longer exposures and higher magnifications, sources of noise are greatly amplified. But these sources of noise are largely random. By stacking images on top of each other (literally what it sounds like), random noise averages out to nothing, while the clarity of the object is amplified. For deep-sky images, 10, 20, even 50 images are stacked. If each sub-exposure is 2 minutes, for example, and there are 20 of them, you'll see 20x120s under the photo in the gallery. If it is an lrgb image, that means I spent a total of 20x2x4=160 minutes acquiring images, for a single resulting image. That's a long time - and I'll be going even longer for dimmer objects. For planetary images, detail is everything and since the exposures are short, they combine hundreds of individual exposures for one resulting image.

Post-Processing - Computer Magic:
Even after everything else, there is a lot more processing to be done. Some of the steps:
--Wavelet Processing - Frankly, I don't know how it works, but it is a mathematical way of finding and enhancing detail.
--Stretching - Pretty much what it sounds like. Colors are assigned a number from 0 to 255, with zero being black and 255 white. By cutting the top to 128, for example, and stretching the rest, blacks stay black, but dim colors are made twice as bright.
--LRGB Combining - Discussed above. It is how color photos are made with a black and white camera and filters.
--Color Balancing - What it sounds like. Sometimes, due to filter transmittance and camera sensitivity, colors are balanced by varying the exposures for different colors. Other times, it is done in post processing.
--Background Noise Reduction - Sometimes the background comes out grey (or even green). The color spectrum is adjusted to cut it back to black.

Phew. If you got through all that......I won't believe you - but thanks anyway!

February 14, 2007 - Bad News from 2006

Part of the reason I didn't update my site in 2006 was that my laptop died in the summer, taking a good 8 months worth of not-backed-up astrophotos with it. You may notice as a result that there is little from the winter, spring, or summer of '06, except for the few I could recover from postings on message boards.

April 13, 2006 (taken from a post on www.physicsforums.com ): Selecting an Intermediate Level Telescope

For a first decent telescope in the $800 range, you have the Meade ETX, the low end of the LXD75 series, the Orion Skyview Pro, or the Celestron C -- GT series.

If I had the chance to do it again, I probably would not have gotten my ETX. I would have either spent a little more for an LXD series or gotten an Orion for about the same price. Part of the problem there was that I already knew I wanted to go the next level up, but didn't quite have the funds yet, so I wanted something to hold me over until I could get something better (which I am about ready to do). I actually bought a $400 Meade reflector that was junk, decided I was willing to spend $800, then didn't spend enough effort on the decision.

Some key issues:

Focal Ratio (ratio between focal length and aperature):
This is probably the biggest issue. It is what determines whether or not you can do deep-sky imaging with much success. Lower is better and if you want to do deep-sky, having a high focal ratio is an absolute killer. At f14, my ETX requires eight times the exposure of the Orion Skyview Pro (f4.9 - you ratio the squares) to get the same brightness. Now mine can work with a focal reducer, which brings it down to about f7, but that still means double the exposures. Similarly....

Very close second. My mount has a tracking bug that makes exposures over 30 seconds impossible (and even at 30 seconds, I can only keep about half). Some people have gotten better, but the ETX is hit or miss. The Skyview Pro is better, though even then people say getting 2 minutes unguided is difficult with any scope. Still, that means you can get 8x brighter images with the Skyview than I can with my ETX, without having to jump up in difficulty to autoguiding. There are a lot of deep-sky objects in range of a scope like the Skyview, not a lot in range of mine.

Aperature/Focal Length:
Since most scopes in the same product line/family have the same focal ratio, bigger scopes essentially just yield the same brightness but a bigger image. For planetary, though, aperature=resolution.

Scope Type:
Real quick, reflectors or CATs (half refractor, half reflector) are generally the most versatile and therefore best bang-for-buck.


There are three basic options:

For planetary imaging, a decent webcam (Quickcam 3000 or 4000, or anything with a CCD, not a CMOS imaging chip) will match or exceed the results of a more expensive camera. Regardless of if you are going to move up to deep-sky imaging, I highly recommend starting out with a webcam. People make adapters, but all you really need to do is remove the lens and hot-glue a 35mm film canister to it. Then it goes in place of your eyepiece.

By shooting videos and stacking hundreds of images with software like Registax, you get about double the resolution from the final pic than in any individual image.

Low-end deep-sky imagers:
Meade makes a camera called the Deep-Sky Imager ($300) and Orion makes the Starshoot ($400). They come with software that takes the pictures and they have image processing suites with them. They are a good start, but they are low resolution and low sensitivity. One big drawback of the color DSI - it is actually a monochrome camera with a grid of filters on it. That means its output resolution is really only a quarter of what the CCD is (and therefore advertised as), and it is noticeable in some of my photos. I don't think the Starshoot has that issue.

Midrange CCD Imagers:
The next step up from there is the monochrome DSI II ($700), or competing products in the up to $1500 range. The obvious drawback is the need to shoot three(or four) sets of images to then combine the colors via software. Benefit: sensitivity and resolution.

DSLR Cameras:
On a similar pricerange is a regular digital SLR camera. Their benefit is bigger chips (for wider fields of view) and higher resolution. Drawbacks are that they are unsuitable for planetary imaging and their sensitivity is lower than the dedicated astrocams at similar prices.

You can also piggyback (means exactly what it sounds like) a dslr with its lens to take really wide-field pictures. I coupled an slr lens with my DSI for a few of mine.

December 3, 2005: Intro/History

I figured I'd start off with a little history on me and my hobby...

I'm 29 years old and I got my first telescope for Christmas when I was in high school - I'm not sure what year. The telescope is a Tasco 60mm refractor on an equatorial mount. My dad actually got a slightly cheaper version on an Alt-Az mount, but recognized that an equatorial was better and we got it exchanged. Though I've actually heard differing opinions on that, I'm glad we traded it in: the equatorial mount provides much easier tracking and finding of objects. Anyway, with that telesope, I could see the major planets, the moon, and the sun. It isn't a great scope, but it kept me interested - and wanting more. And I still have it - I may yet use it as a guidescope in the future.

A little over a year ago, after reading about techniques and software using a webcam for astrophotography on the web, I tried it for myself. It's astonishingly easy: take a webcam, disassemble it to remove the lens, and hot-glue a 35mm film canister to it. It fits perfectly into the eyepiece holder of a telescope. The first pictures I took were terrible. But it re-lit the fire, and before I even tried to do better with that old refractor, I bought a new scope...

I bought a Meade DS2114 4" Newtonian reflector, with computer control for $400. I should have realized that it was too good to be true - to get that price, they had to cut corners everywhere. So I sent it back and bought an ETX-105 Maksutov-Cassegrain for $800. It's a decent intermediate scope - though not without limitations, which I will get into more later. For about the past year, I've gotten about all I can out of this telescope. I've used it dozens of times - occasionally driving to the Poconos to set up in a nice dark, random parking lot. Mostly, I use it at a local golf course. I've even set it up for parties - with its guidance, I can point it at something and let it go for a long time. My friends get annoyed, though, if I leave a poker game to check on it ;)

The camera I'm using right now is a Meade Deep-Sky Imager ($300). It's not bad, but it also has limitations, which I'll also go into later. I started with a webcam, but webcams don't do long exposure, so they are pretty much limited to planetary photography. Unless, that is, you can modify them to take long exposures... People have figured out how to do just that, and instructions and schematics are available online. The problm is, modifying them requires lifting and soldering pins on the circuit board. At maybe a milimeter thick, with a milimeter spacing, it's tough work for someone who has little experience with such things: I destroyed two webcams before deciding to buy the DSI.

Because of the limitations of my scope, I'm starting to contemplate an upgrade. However, I've promised myself I won't buy a new telescope until I buy myself a house. So now I'm starting to look for both ;)