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Cristian Willemoës
8" f/6 Reflector Starfinder Meade
20-second exposure. Faked color.
Kodak Tri-X 400 ASA a 3200 ASA

SUMMARY:

The general features of the process will be described so that everyone will be able to define the method, kind of film, time of exposure and developer solution that best adapt to each equipment. All the illustrations herein have been made with Kodak black and white Tri-X (400 ASA) and processed according to the text (3200 ASA and 6400 ASA). All the objects in deep space have been taken on 20-second exposures prime- focus, using a 200 mm Meade Starfinder telescope, in a highly polluted urban sky.

THE PROCESS IN THREE MAIN PHASES:

1) Expose the film to a speed 8 times faster than the one recommended by the manufacturer. For example, a Plus-X film should be picked up from 125 ASA to 1000 ASA and a Tri-X film should go from 400 ASA to 3200 ASA. Now, according to my experience, only 20 seconds are needed when using a 200 mm f/6 telescope for spotting deep space objects at a prime-focus. However, this lapse can be lessened by increasing the process sensibility. For brighter bodies like the Moon, the sensibility range on the light meter must be taken to 3200 ASA in order to speed up the shot. Thus, the film will not be overexposed. For deep space bodies, cover the telescope with any dark element, then shoot. After that, the dark element must be removed from the telescope for 20 seconds. Cover the telescope once again and finally close the drop shutter. The telescope must not be touched at any moment in order not to produce any vibration that may alter the image. Due to the minimal exposure achieved through this method, a great number of photos can be taken in one single night. That is to say, 1 or 2 full rolls which will be developed together at the end of the session.

2) Prepare the D-76 concentrated developer solution. It is U$S 5 per 1 liter of concentrated solution, good for developing between 22 and 30 rolls, depending on the kind of forcing applied and the tank capacity. The formula is: 1 part of concentrated solution + 4 parts of water.

3) Develop the film with the prepared solution, and increase the periods suggested by the manufacturer to five times. (20�C for 40 minutes). Then, wash the negative fully and fix it the usual way. You will notice a negative with the proper density and a quality higher than normal, perfect definition and contrast, great degree of tone, and fine grain.
One of the most outstanding features is the abundance of details, either at high or at low lights. All these characteristics can only be met with a fine grain film like Plus-X and Tri -X by Kodak and a developer like D-76 by Kodak, the so-called compensators.

Eta Carinae Nebula Binnewies, Riepe y Sporenberg 11" f/7 Celestron 85-minute expo- Hipered Kodak Ektar 100 ASA

Eta Carinae Nebula Cristian Willemoës 8" f/6 Reflector Starfinder Meade 20-second exposure Kodak Tri-X 400 ASA a 3200 ASA

Eta Carinae Nebula Cristian Willemoës 8" f/6 Reflector Starfinder Meade 20-second expo - Faked color Kodak Tri-X 400 ASA a 3200 ASA

Orion Nebula Cristian Willemoës 8" f/6 Reflector Starfinder Meade 20-second exposure Kodak Tri-X 400 ASA a 6400 ASA

Orion Nebula Claudio Bottari Astro-Physics 7" f/9, Filtro Hidrógeno Alpha, N. B. 6-minute exposure CCD Camera Spectra-Source HPC-1

HOW TO PROCESS THE FILM YOURSELF

It is easy to calculate the relation among the increase of sensibility, dilution of the drug and developing time. You just need to add as many parts of water to the concentrated solution as points of ASA at which the exposure has been modified + 1 more part of water

As these recommendations from the manufacturer show, for a 400 ASA Tri-X film you need 8 minutes of development (with D-76 developer solution) at 20�C. But if you increase the sensibility, you will have to raise the parts of water, according to the points of ASA increased as well, + 1 more part of water. Then, multiply this total by the suggested time. ....at 20º C = 8 minutes x 5 times = 40 min

Here is another example: Let�s say the object to be photographed is extremely weak and we prefer to darken the negative a bit more, developing at 6400 ASA, the formula will then be:

.at 20º C = 8 minutes x 6 times = 48 min

For all cases, at the beginning of the process, the tank must be churned continuously for 2 minutes. Through this, all the bubbles will be utterly removed. You must repeatedly shake the tank for 1 minute and let it rest for ten minutes more until the end of the procedure, so that the developer is constantly renewed.

OTHER HIGHLIGHTS

47 Tucanae 20-second exposure to 6400 ASA. C.W.

The goal of this method is to obtain the most suitable negatives to be copied and to avoid the use of professional processing laboratories for the negatives, then you can use negative-scanners to produce an outstanding result. You can also copy the negatives on paper and later on, scann them the usual way. All the pictures in this article have been copied in a homemade amplifier and then scanned and processed on a computer.

M6 20-second exposure to 3200 ASA. C.W.

As you can see, the reduction of the time of exposure is remarkable, even though the main cost of the procedure is given by the long development time. Yet, this cost is not substantial in relation to the development temperature and the procedure itself. On the contrary, it may well be more than convenient: in 40 to 50-minute developments, the variations in temperature are not significant, The same applies to the time you take in replacing the developer for the fixer. On the other hand, these might alter those negatives developed during shorter periods of time.

NGC 3293. 20-second exposure to 3200 ASA. C.W.

Shaking the tank during the developing process may result in a problem for regular developments due to the long time it takes the drug to become active. Another consideration is the economical benefit derived from the chemicals to be used, especially the developer, since the drug is greatly diluted. You should dispose the developing solution after each process, but you do not need to do this with the fixative.

I recommend heating the developer solution 5�C more during the process, using stainless tanks instead of plastic ones.

M22 - 3200 ASA - C.W.	M7 - 3200 ASA - C.W.	NGC 5281 - 3200 ASA - C.W.
NGC 6231 - 6400 ASA - C.W.	NGC 6530 y M8 - 6400 ASA - C.W.	NGC 4755 - 3200 ASA - C.W.

One of the dramatic characteristics of this method is the wide range of exposure it provides when forcing the film. I was taking pictures of deep space and decided to force the negative to 3200 ASA. The Moon appeared almost at the end of the session. Although I could have cut the negative and processed the shots in many ways, I decided to shoot the Moon with my camera at automatic shutter speed. The range of my Pentax is 1600 ASA, and I had already taken all the other pictures al 3200 ASA. I decided to shoot anyway! When developing those pictures, I realized that the shots of the Moon had come out really good, with a great variety of gray shades, and they could even be copied without any problem as well, even though they were a bit darkened.

PREPARING THE CHEMICALS


All you need to do is follow the manufacturer�s instructions carefully. The required solutions are Kodak D-76 Developer and the fixer. Both come in ready-to-use pouches. To prepare 1 lt. of concentrated developer, you must heat 900 ml. of water at 52�C. Then add the powder during 5 minutes, stir until it becomes crystal-clear. After that, pour the remainding 100 ml. of water at room temperature to complete the liter. The solution should be stored in dark bottles or accordioned plastic jars in order to let the air out. It can last a couple of months when properly stored. The same method applies to the fixer, but the temperature must be 27�C. This solution can be used several times, either on negatives or on paper. The paper developer differs from the film developer. Dektol by Kodak is recommended here. Its preparation is similar, but the temperature must be 38�C. It produces 3 liters of solution. The storage time is limited to a short period if not properly kept. .

HOME ACCESSORIES TO BE USED.

For prime-focus photography with Meade Starfinder telescopes, the primary mirror should be set to the second position but this action does not allow to see or focus with eyepieces. To avoid moving the primary mirror, you will need to make a sepecial ring-shaped threaded plastic fitting, attachable to the 2" adaptor which comes as an accessory to the telescope. Then fix it with epoxi glue to any camera adaptor. To copy the negatives on paper you can make an amplifier with a shoe box or any similar box, fix a bulb socket in it with a 75-watt bulb, as well as an electrical wire and switch. You must make a diffuser in the box, adding a couple of emery glasses or plastic sheets. Then you must adapt an objective, ideally with a diaphragm and a wide focal length range. The negative frame can be made with 2 cardboard sheets which will be inserted in a slot carved in front of the objective.

As you can see, with little money and a bit of creativity, you can produce good shots from your own backyard, reaching a magnitude of 13.5 in city skies. Yet, you may require some more accurate devices and some 1-minute exposures to shoot God arguing with The Devil at the bottom of the Universe...

Less is More ...

Architect Cristian Willemo�s
[email protected]
[email protected]
www.geocities.com/cwillemoes
Titular Associate Professor - UCALP
Practical Works Chief - UNLP
Principal Professional - Physics Institute La Plata - IFLP - CONICET
Section Coordinator: CCDs - Iberoamerican Astronomy League - LIADA

Translated into English by Alejandra De Gennaro
[email protected] - [email protected]