New in photography

[Tweefo]

I own a 8"LX90 and would like to take astrophotos. What equipment do I need? Inexpensive!

[rager]

same here , i need to know thanks ;)

[Kaptain K]

Alt-az or EQ?

[Tog_]

I own a 8"LX90 and would like to take astrophotos. What equipment do I need? Inexpensive!

I have this same scope and can give you a bit of a list and a place to start, but it will have to wait until later today. I have to actually do some work now...

[Tog_]

Okay, step 1 you need to decide of you want to use film or digital. Digital will be more expensive to get started, bt may work out cheaper in the long run.

For film you will need a camera body. You probably want a fully manual 35mm single lens reflex camera (SLR) Pentax makes a new one, or you can look through pawn shops for one. I have an old Minolta that my dad got in 1967. It went through 4 helicopter crashes and still works great. The 4 main things you want in a camera body are (in the oder I think they matter most)
A bulb setting. On the dial that sets the shutter speed, there will be a set of numbers that count down from 500, 1000, or 2000 to 1. after the last number, will be the letter B. When set to bulb, the shutter will stay open for as long as you hold the button down. With the newer electric cameras, it will use up the battery to do this. You will need this for long exposures.


A place to insert a cable release. The shutter release will have a threaded hole in the center if it accepts a cable. The cable will allow you to press the shutter when you are not actually touching the camera. They also have a small screw that will hold the button in and the shutter open until you release it. This is important beacuse you will have a very difficult time not shaking the camera if you're holding the shutter open with your finger.

A mirror lock up. This is optional but nice. In an SLR, the light will come in through the lens and hit a mirror set at 45 drgrees. This mirror sends the light up to the top of the camera where a prism passes it out through the view finder. When you take a picture, two things will happen. That mirror will flip up, out of the way, and the shutter will open. Often, the mirroe will slap with enough force to cause the camera to vibrate up and down on the mount, causing a bluring of the image. A mirror lock is nice becasue it will allow you to get the mirror out of the way before you open the shutter. The shutter may hae some slight horizontal vibration but that is minor compared tot he mirror slap.

A changeable view screen. I dont have this on mine, but it would be nice. Most SLRs have a view screen that looks like a lot of tiny triangles. This it fine for focusing on well lit objects, but to get a planet in focus with it is tough. Some cameras will allow youto swap out the crossed prisim like back for a clear one that would be almost like using an eyepeice.
For film you will also need a equatorial wedge. The scope will track fine in alt-az mode, which the normal configuration with the arms of the fork mount pointing straight up. The problem is that for long exposures, the image in the field will rotate as the scope tracks it across the sky. The image in the center will be okay, but you will get arcs as you get further from the center. A wedge will allow you to polar align the scope. Here, the forks are pointed directly at the north or south pole. For the north that's Polaris. For the south, I'm not sure.

For exposures of longer than 10 or so minutes you will also need a guidescope or off axis guider. The guidescope is a smaller scope, usually a light refractor that mounts on the main scope. THe off axis guider is a thing that goes between the camera and the scope and has a tiny little... thing that will collect a bit of light ans shoot it out the side. No matter which one you use, the basics are the same. Get a high magnification EP, preferably one with a crosshair in it, illuminated if possible, so you can see it, and put it on a bright star near your target. Keep that star in the same spot in the guide scope for the duration of the exposure.

Once you have the pictures on film, you will need to find a custom lab. Most grocery store and other bulk film developing places run it through a machine that scans the negative for any exposed bits. The place near me had an 85% threshold. If the picture was 85% or more black it didn't get developed. No astrophotos come through. Oh, it's also a good idea to take the first picture on the roll as a normal picture, in daylight, so the lab will know ehre to cut the negatives.

Film and processing will add up fast.

For digital imaging, the Meade LPI is a good way to get started cheap. It's not much good for deep sky images, but it's not bad on the Moon and planets. It has a tiny field of veiw though. They also make one for deep sky imaging.

An imager for a telescope is a CCD, not a digital camera. Many of them come with software that will look at two points on the picture and de-rotate the field for you. This will save on the wedge. They also don't need film an processing, so once you have the stuff, the spending is about over. The down side it that you do need a computer to run most of them. That means a laptop and a way to power it when miles from anywhere. I have a converter that will let me plug in any light draw AC device intot eh cigarette lighter in my car. I got it from CompUSA for about 50 bucks. It will even turn itself off if the car battery drops below 10 volts.

Other will have more to add on the subject, especially on the digital side, but that should give you an idea. This is also something you'll want to get a good book about. Threre are a lot out thre, especially for an 8" SCT.

Odds are that it will take a while to get a good shot. When you do, we want to see it. Good luck:)

[Gob332]

Hi all,

I am also new in astrophotography so I thought that this would be a good place to post this question. I am, as mentioned before, completely new to not only astrophotography, but photography as well. The camera I plan to use is a SLR Nikon EOS Rebel G. It has a fully manual mode and a bulb setting. However, the F-stop only goes down to 4.0. Is this not small enough? Does the f-stop change with the type of lense you use?

I'm waiting on a cable release cord so I can't really test it out yet, but these were just a few of my worries.

Thanks for the help.

[Dave Mitsky]

You should consult these sites:

http://www.covingtoninnovations.com/astromenu.html

http://www.geologynet.com/astronomy/astrophotography.htm

http://www.geocities.com/CapeCanaveral/Lab/6529/primer.html

http://www.photosig.com/articles/390/article

http://www.allaboutastro.com/

http://www.eclipsechaser.com/eclink/astrotec/aphotsmt.htm

Picking up a copy of Michael Covington's book wouldn't be a bad idea - http://www.covingtoninnovations.com/astro/index.html

BTW, you can certainly use a digital camera for astrophotography. A DSLR is necessary for DSO prime focus work but a point-and-shoot digital camera can be employed afocally for the shallow sky.

http://ghonis2.ho8.com/index.html

Dave Mitsky