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About Dave's Astronomy Website
Information about the images shown on the site
M31 - Andromeda Galaxy
This website is a collection of night sky images taken. The collection includes images of stars, clusters, galaxies and nebulas. Most of images were shot from my backyard or from one of the many dark sky locations found in Alberta.

I have found that observing and taking pictures of the night sky to be quite interesting and rewarding. I hope you enjoy the images.

David J. Ritter

Cameras and Telescopes

The images on this site were taken with digital cameras attached to computer controlled telescopes. The camera currently being used is an SBIG STF-8300M. This is a monochrome CCD camera with an 8 position filter wheel. The filter wheel has red, green and blue filters for gathering color data. There is also an L filter which is a clear IR/UV cutoff filter for gathering luminence data. The remaining filters are Ha, OIII and SI which are narrowband filters used for nebulas and other deep sky objects with specific emission characteristics.

In the past I have used a few different full color CCD and DSLR cameras so a number of images on the site were made with them. Moving forward I expect to stay with monochrome imaging using filters. So far that has proven to give me the best results and they work quite well, even from a light polluted city.

The imaging telescopes include a CFF 132 refractor, a Celestron 11 inch EdgeHD Schmidt-Cassegrain reflector, a Tele Vue NP101is refractor and a Sky-Watcher MN190 Maksutov-Newtonian reflector. I also own a few other telescopes, some of which are used for auto-guiding and others for visual use. They include a Sky-Watcher ST80, Lunt LE80OTA, Vixen VMC110L, GSO 6inch f6 Newtonian and a Vixen A80Mf.

Mounts and Auto-Guiding

My primary imaging mount is a 10Micron HPS GM1000. I also have an NEQ6 which I use for visual observing and equipment testing. In the past I've had an EQ8 and also a CG5. All of these mounts have been used for images found on this site.

All long exposure images are now being done using an autoguider. The current autoguiding setup is a LodeStar X2 camera fitted it to a Sky-Watcher StarTravel 80 with a GSO 2X barlow. The guiding is further enhanced with a Baader longpass Red+IR filter. I also have a Celestron Off-Axis Guider for use with the SCT and another 80mm refractor as well as a couple of spare cameras. So there are a few ways I can get the guiding done now. Some short exposures taken with the C8 were unguided.

I am now using the ST80 as a guide scope. The Vixen used on lots of the images here worked very well indeed. But it was sort of long and heavy so I switched to the ST80. This is working very well with the 10Micron mount.

How the Images are Processed

Most of the images shown here are composite stacks made from a number of individual photographs. Depending on the conditions, individual exposures vary from less than 30 seconds up to several minutes. The stack can be any number of these exposures. Once the individual frames are collected, software is used to stack the frames together to form a composite image. Final processing is usually done with photo editing software for brightness and contrast adjustments as well as cropping and resizing.

As for image quality, if you go through the site you may find some that are pretty poor quality indeed. I am well aware of that and decided to leave them up anyway. Some are like that because they were test images or specifically done to illustrate an astronomical object rather than to be a pretty picture. Others are pretty bad because they were done long ago while I was still in the early stages of learning astrophotography.

These lesser images will probably stay up for a long time too. In several cases they show the progression from beginner to where ever I am currently. In other cases they show one time events and there is no way to go back and re-take them. Comets and supernova come to mind here. So, if you're just starting out, hopefully you can learn from some of my mistakes and not be embarrased if your pic's don't stack up against Hubble for example. You have to start somewhere and like any skill, the more you practice, the better you will get. And if you're good at this, here's a place to have a laugh and maybe remember some of the bloopers you did too.

Exposure Times and Integration

Total exposure times can vary greatly. Stars and other bright objects like planets are usually done with short exposures. Galaxies, nebula and other faint images can take many hours of exposure time to form a good image. Actual exposure time gathered in the field depends on many things including luck and weather.

Imaging purists will note that I repeatedly use the term "exposure" when I am really discussing integration time. I do this deliberately to make it easier for the general public to understand what's going on. But it does create one common mis-conception, that being the myth that long exposures are needed to reveal dim objects.

In fact, most objects shown on this site would appear in photographs taking only a few minutes to expose. But I usually run many hours worth of images to get to the final product. This is because, through the miracle of stacking, many hours of images result in a clear, almost noise-free image. In other words, the quality goes through the roof after collecting and dozens of separate images and stacking them together.

Software Packages

The softare I am using now includes Sequence Generator Pro (SGP), MaximDL (IP) and Corel Draw. SGP is used to control the camera and gather the images. MaximDL is used for stacking, filtering and stretching the images. CorelDraw is the package I use for final processing, cropping, resizing and format conversions.

Besides these major packages, I also use a few more utilities and drivers. In fact, the dedicated astronomy laptop I put together a few years ago is now getting kind of full with various utilities and packages. Most notably, PHD is used for running the auto-guider and Starry Night Pro is my planetarium package. I also use ModelCreator for automating the sky modelling on the 10Micron mount. EQMOD is used for connecting to and controlling the Sky-Watcher mounts. Besides all these, there are various drivers for things like the Rigel and Optec focusers, MBox weather station and other ASCOM related gear.

Content Management and Web Coding for this Website

The home page, about page and other static pages are hand coded in C#, HTML, CSS, and JavaScript using a very basic text editor. The image galleries are in an image database managed through a custom Access application. The Access app uses data from the database to generate web pages and other source code for the live web site.

Publishing is done manually through the file management option on the website control interface. I can also use an FTP client if I like but so far the web interface works well enough. The site is hosted by SaveOnHosting, a very good hosting company located in Calgary, Alberta.

The site runs on a Windows server platform running ASP.NET and is located in a server room operated by the hosting company. It is developed and tested on a simple laptop running Windows 10 and IIS located in my basement. I am the sole author of the site and it is currently the only website I work on anymore. So all mistakes are mine and mine alone. Including speling errors and the grammer too.

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