Introduction

Let me start off by saying that astrophotography is probably one of the most difficult forms of photography there is on earth...or for that matter, in the universe!

The problem is that not only are the subjects very dim (photographically) but, they are moving! Actually, the earth is moving much faster though, at least from our point of view!

So now, it is vital that we have a sturdy mount that is aligned with the polar axis...and, we need precision motors to compensate for the rotation of our planet. Because the exposure times are more than likely to require 'guiding'. (This is much trickier than 'tracking', which is fine for viewing...tracking is obtained by having good polar alignment and a right ascension motor to compensate for earth's rotation) but, 'guiding' involves fine adjustments in right ascension & declination through a significantly more magnified field (usually through a guiding eyepiece with illuminated crosshairs). You see, because of the relatively long exposure times required for most of our subjects, guiding is necessary. In the first place, no drive mechanism is perfect. Also, due to the 'sphere' shape of our atmosphere...the light that we see from space 'bends' before we see it , and as our subject 'rises' during exposure, the light reaches us at different angles. This is called atmospheric, and differential refraction....Thus, we must make adjustments!

Tips: Before alignment, make sure you have all the 'weight' mounted...cameras..ect...., then leveled,... then balanced,...finally, align your mount!

Exposure Determination

This is even more difficult than guiding! We have to take into consideration not only the lens speed of our equipment, but our film speed, our subject brightness, and the 'darkness' of our site! Taking all of this into consideration,...we must leave the shutter open for just the right duration...(in the meantime 'guiding') and ...WOW! The perfect exposure!

Definitely not...at least not on the first try.

You can be sure that for every good exposure you see, there were several attempts that didn't turn out so good.

A lot of it is 'trial & error'...writing down film speed, exposure time, lens speed, and all variables in order to learn the proper exposure for a given subject at a given location! Incidentally, the proper exposure is determined by you, and you alone...it's what ever you were trying to get!

Of coarse, the best time is on a moonless night and far from the 'light polluting' city.

For an idea of what kind of exposure times to use with different films and f/speeds,...download my FREE, Full Screen, Astronomy Slide Show! Each one of the 19 awesome images includes the variables used to capture them. My latest is Comet Hale-Bopp! (See below)

Framing the Subject

Often, our subject may not be visible through the eyepiece. Many objects which are easily seen on film, are difficult if not impossible to see visually. (Depending on our equipment) Therefore, we must have good maps, and very helpful is a good pair of binoculars, so we will be able to 'star-hop' to the area of sky where our subject resides! Now before we even try this step, we must have already accomplished a sturdy, level, balanced & aligned mount. Also, we must have already made sure our scope, or camera is in proper focus! It's usually easier to focus on some bright stars first, then go to the task of 'framing' your subject. (When focusing, look for focus not only in the center of the field, but also at the edge of the field) Finally, when we think we have our subject framed to perfection, we must find a suitable guide star. Most often a suitable guide star can be found without moving out of our target area. The important part here is to take note of the right ascension and declination movements in relation to the illuminated crosshairs...turn the guiding eyepiece so that the movement during adjustments, is horizontal & vertical to the crosshairs and remember which way the guide star moves for each adjustment button you push.

Now your ready to take that 'perfect exposure'!

Hypersensitizing

Normally called 'hypering'. This is a good way of increasing the sensitivity of your film from 3 to 10 times! There are commercial kits available that use 'forming gas'. This is only 8% hydrogen and therefor non-flammable and safe. Since available films and their specifications change so often, and since different films react differently to hypering, it's difficult to offer specifics on the subject...but, I have found that for medium to long exposures (30min. - 1hr.), Kodak Ektar 1000 and Gold 1000 both increase in sensitivity by about 3x. (That's hypered for 3 days at 15psi. and 30 degrees Celsius) This means cutting your exposure time to about 1/3 or even 1/4 of what it would normally take!

Film Development

Last but not least! We've worked so hard...even traveled many miles to dark skies...nearly froze to death! Braved the mosquitoes, chanced the weather and much more in order to capture our precious exposures!

Do not: Take your film to just any photo shop! You must find a quality film lab and talk to the lab technician...(find one who is willing to bend over backwards in order to process your precious negatives to the perfect background color). It's very helpful if you have a 'guide print'. Also, tell them not to cut the negatives right of way! Astrophoto's can be difficult to discern between exposures.

The other options are learning to do your own processing, or use slide film!