Saturday, February 20, 2016

Common Questions About Analog Astronomical Photography

As a photographer who works with film, I often get inquiries on various social media as to how the images are done. This is especially true of my long exposure images. The most common questions have to do with exposure, equipment used, and how do I get those stars to be pinpoints if the exposures are an hour or more.  This blog post is my answer and I will link those that ask to it.

Astrophotography used to be the domain of amateur astronomers; astronomers did astrophotography. With the advent of the digital workflow, photographers have entered the domain, at least with what can now be done with a fixed tripod and camera arrangement. Professionals especially are well suited to produce excellent results with digital cameras. They have the resources at hand and workflow experience in post processing to best the work of what the astrophotographers of old used to struggle to accomplish with film.

Enter film based astrophotography. This is how it was done just fifteen to twenty years ago. There was really only one way to capture Milky Way vistas - with film.


The Sagittarius Milky Way Pentax 67 with 400mm SMC Takumar - Superia 100


One dispute over many professionals is experience. They are not astronomers, but many are bright enough to pick up on the basics of how the sky works. Some are truly gifted sky enthusiasts and as such produce superior work.

Personally, I do not recommend those just starting out with their interest in capturing the night sky photographically to use film. Digital is faster, easier, and encourages beginners to continue their efforts. Film based work can be unforgiving. I've tutored a few individuals who attempted it and were discouraged right from the beginning. There is so much that can go wrong.

So why film? I use film simply because it is what I have always used since I learned the craft in the early 1980's. In 2007, instead of switching to digital, I stepped up to medium format film. In 2016 I am still using film, although I have done some digital work. My other reasons for using film are aesthetics, continuity with traditions started by early astrophotographers such as E.E. Barnard, Max Wolf, and more recently, David Malin, to name but a few.

The nigh sky view from the observatory
Successive images overlapped to show fields captured with 400mm Takumar


For me this is an avocation and I can please myself with what I do, such as there still people who paint or sketch. When I perform my best work, I get great remarks but they are often mystified by my use of film despite my doing well with it. This seems to be the default nature of modern photographers. It prompts the question as to why? This also presupposes that there is no advantage to film, only disadvantages. But this simply is not true.

The Milky Way of Taurus and Perseus

Bright and dark nebulae populate this wintertime target

Pentax 67 105mm f/2.4 @ F/4 Kodak E200 - 1 Hour Exposure


Film images exist. I can show them to you. They are not virtual images or a representation of a kind. Original images exist in tangible form. They are imperfect, and they are vulnerable to the years following development.  Done properly, noise is never an issue in long exposure work with film.  Color films such as Kodak E200 deliver high fidelity red sensitive portraiture of the night skies.  Most digital cameras, DSLR's namely, need to be modified for extended red sensitivity.  Finally, rendition.  The look of film is unique.

Workflow  

The crux of this essay is to convey just how it's done. Analog astrophotography requires patience, years of practice, and perseverance before anything else. Good cameras, the proper films, and a way to share them in online communities are also required. The act of the image taking process itself is a sort of art.


The basics:


Access to dark skies away from city lights, good weather, and no Moon dictates where and when to do the exposures.

A properly aligned equatorial mount with provisions to compensate for the Earth's rotation is also a requirement. This may be the hardest part for many. I use a permanently mounted fork mounted telescope permanently aligned with the celestial pole. The celestial pole is the point in the sky where the Earth's axis point towards. Aligning the polar axis to this point allows the equatorial mount to work in parallel with the Earth's own polar axis. Alignment to within a few arc-seconds will allow extended tracking without trailing of star images during the exposure.


Heavy lifter!
Pentax 67 and 400mm SMC Takumar Riding Piggyback an 8" SC Telescope


A second part of this tracking mount is the clock drive. It's job is to rotate the polar axis counter to the Earth's rotation. It also needs to be accurate. Being a mechanical worm gear with a period of rotation of its own brings forth periodic error. No gear is perfect compared to the precision of the Earth's rotation, so we also need to correct this as time goes by. To do this we incorporate a drive corrector. The drive corrector allows the photographer to monitor a guide star as a reference to the Earth's rotation and manually correct via a small hand controller to speed up or slow down the clock drive when appropriate. This is called guiding.

The Small Sagittarius Star Cloud -Messier 24 Region
Pentax 67 400mm SMC Takumar @ f/5.6 Fuji Acros 100 1 hour Exposure


One can employ a small CCD camera in place of the guiding eyepiece to monitor the guide star and do the corrections automatically. This is called an auto-guider. It does the labor of constantly correcting the drive as needed. I do not use one, as I monitor the guide star (through the telescope the cameras are attached to) and correct manually. This is tedious work. Discouraged already?

A session goes like this:

At dusk, the camera is loaded with film (if not already) and mounting shoe to attach to the telescope is mounted to the 1/4-20 threaded tripod socket on the camera body, or telephoto lens mounting plate.

The telescope is exposed to the sky as the roof is rolled back at the observatory. Optics are checked, guiding eyepiece is installed and prepared to receive the camera.


The Piggyback mounted Pentax 67 with 165 f/2.8

The mount is made by Losmandy


The camera is mounted atop the telescope (this is called piggyback mounting) and locked into position at the proper balance point of the arrangement.

An area of the sky is selected for exposure. This involves lens selection for framing of a particular field. Lenses routinely used for this range from 105mm to 400mm focal length for the Pentax 6x7.

Once the field to photograph is established and the telescope is locked in place, a suitable guide star is centered into the double cross-hair eyepiece. This eyepiece is of the proper magnification to offer guiding corrections less than 10 arc-seconds. The star is centered at the same time the camera shutter is ready to be opened. Focus on all my Pentax 67 lenses are set at infinity stop as this seems to be true infinity. Lenses are stopped down to usually f/4.8 or f/5.6 for fully illuminated fields.

The exposure begins...................... The guide star is monitored and hand corrected for accurate guiding during the exposure. This can range from a short exposure of twenty minutes, to long exposures of an hour or more. Ninety minutes is the longest I've used in practice. One hour is typical.

In the Observatory with setup for a nights session of film based astrophotography!


Once the exposure is done, the shutter is closed and next frame advanced if another exposure is to be taken that night.

During exposure the sky needs to be scanned visually to make sure aircraft do not enter the photographic field. Gently capping the lens while the aircraft (or satellite) passes by, then removed to resume exposure. I've often capped the lens for five to seven minutes on a one hour exposure during busy aircraft times.

Wind. A windy night prevents most work from being done with longer lenses. Wider angle lenses can usually be employed with such conditions.

Dew. Nighttime moisture tends to build up on optics and this needs to be prevented or the lenses will fog up, causing stars to have halos. A small hair dryer works well. Gently “spray” the lens with the warm stream of air every 10 minutes on moist nights. Heating tapes can be purchased for such use as well. I use a hair dryer.

Developing films. Color and B&W films can be processed normally or push processed to bring out faint details. Only two currently produced films work well for astrophotography, Fuji Acros and Fuji Provia 100F. Legacy films such as Ektachrome 200, Superia 100, and Fuji 400F work great!


The Milky Way of Southern Ophiuchus
Fuji Acros 100 Produces fine astrophotographic images.
Pentax 67 400mm @ f/5.6 Fifty-Minutes Exposure


A scanning workflow is best done at home. With experience, more details and tonality can be elicited from your films. Post processing in Photoshop and astrophotographic softwares is of great benefit to film images.  Transparencies and negatives contain much more information than you might expect. Film has the added benefit of having less noise than digital captured sub-frames, so detail is high given proper exposure and proper guiding under ideal conditions.

Film based astrophotography has been a rewarding pastime. I've enjoyed the long hours under the starry dome, slowly building up photons on photographic films.  If anything, it has been a meditative process. Slowing down and doing it the old fashioned way, it is still a great way to capturing the heavens.


Flanders Pond Observatory

A shelter and a permanent setup  makes it all possible.  


More images at my Flickr site.  You can monitor my efforts, both film and digital on my Facebook page.  Twitter fans can find me on my Twitter feed.








Saturday, October 24, 2015

Obtaining Films In A "Post-Film" World

Analog photographers are passionate for their film stocks.  Emulsions are the fabric of their images, the palette conveying their work.  The technical requirements are rather important in astrophotography. Film manufacturers, although having never made an ideal film for the craft, have come close on occasion. Today there are only perhaps two films viable for astrophotography, Fuji's Acros 100 and Provia 100F.  The ideal films of yesteryear, such as Kodak's E100S and E200, or Fujifilm's Provia 400F and Superia 100 are all gone, save for the frozen stocks sitting quietly in the freezers of analog photographers.

Older stocks from the late 1990's, despite being frozen, are nevertheless decayed passed there usefulness. The latest incarnation of capable films from the 2000's will keep awhile yet.  Film degrades with time, with slower films doing well even after 10 years in the freezer.  For best storage life film must be purchased and frozen before it expires, and it must be consistently held in "suspended animation".  Therein lies the rub, finding this properly kept stock in late 2015.

Recently I have had a stroke of good luck in obtaining good film. A favorite color film of the last ten years has been Fujicolor Superia 100. I happened to come across a brick of it from an online source.  It had been frozen since new in 2008 and the price was more than fair.  Ten rolls of Superia will keep these wheels greased for some time to come.

A treasure trove!  To my good fortune, a fresh frozen brick of Fujicolor Superia 100 

The last great color film for astrophotography is Superia 100.  Not to be confused with Superia Reala 100, a great film for daylight use, Superia CN 100 defies it's specifications.  It is red sensitive, but spectral response drops off near 650nm, just shy of Hydrogen-Alpha emission line.  The manufacturers recommendation for exposures past 60 seconds is a full stop increase in exposure, not what you would expect in a good astro-film.


The beautiful region of Cygnus and Cepheus captured on  Fujicolor Superia 

Despite its apparent disagreement with its published specifications, the film performs rather well.  A 30 minute exposure at f/2.8 creates a dense negative capable of tremendous depth and fidelity.  For the best red sensitivity, Kodak's E200 has yet to be beat, however Superia's low halation allows pinpoint stars offering a more refined image.



The area of Scutum revealed by Fujicolor  Superia 100




It's time to get busy with the new stock.  I have yet to use Superia 100 on the winter sky.  I'm anticipating great results on a variety of regions of the Milky Way.  



The Messier 8 Region in Sagittarius on Fujicolor Superia 100


I believe my pursuit for film stocks is over.  Within 5 to 10 years I will complete my portfolio of astronomical images and start working on other projects.  Having photographic film originals versus digital files is a workflow choice. It is not for everyone.  May you find your methods just as rewarding.  









Saturday, February 28, 2015

Holding Pattern -Thoughts on the Coming Season



The winter of 2014-15 here in Maine has been the snowiest in a few years, akin to the 2010-11 season.  If that isn't enough to cancel imaging plans, February is going into the record books as the coldest recorded !  


Flanders Pond Observatory on The Last Day of February 
I've traded hobbies for the last month or so, swapping out the camera for a snow shovel.  Not much fun of course, but a break in the action gives one time to reflect on the upcoming season and the body of work to work on.  

The old observatory has seen better days and this spring will be a time for repairs.  The moist location has taken its toll since it's construction in 2003.  The floor and walls are needing attention, the roof however is good as the day it was built and can hold a good snow load and still slide with relative ease.

Imaging plans will include a fresh look at Sharpless 2-27 in Ophiuchus with an experimental technique for enhancing the capture of this very faint nebula. It is rarely imaged by any means and the combination of red sensitive color emulsion, proper filtering and clear dark skies will bring success.

Sharpless 2-27 in Ophiuchus

The emission nebula Sh2-27 is centered on the young zeta Ophiuchi, a runaway star.  This O type star excites the interstellar medium revealing the "bright" nebula.  The nebula itself is huge and if one could see it with the unaided eye would span 20 full Moon diameters!  Wide-field optics are necessary, even a small telescope cannot capture it in its entirety.  The image above was taken with a portrait lens looking just above the center halo of our Milky Way galaxy.

It is a challenging object to image.  It has a low declination and even natural sky brightness cloaks it from unfiltered cameras.  It usually shows up as a rather large and faint indistinctive patch of light on red sensitive film or astro modded DSLR's.  It came to my attention 10 years ago when imaging with a simple 35mm camera and 50mm lens.

Watch this blog for more information on Sharpless 2-27.  I'm hoping to best my results from 2008 and a full write up on this interesting object.










Sunday, January 11, 2015

Comet Lovejoy and a Close Planetary Conjunction

As the weekend kicked into gear Friday night, two thought were on my mind.  The first was the close conjunction of Venus and Mercury, the second was of C/2014 Q2 Lovejoy.   I dedicated Friday night to some trial images of comet Lovejoy.  The comet was speeding north into Taurus and brightening nicely.  The Moon was well past full allowing dark skies for the next two weeks.  Now was the time to strongly consider imaging our recent visitor and take in the sights as well.

Images taken Friday night with the SMC 67 200mm f/4 lens and Pentax K-5IIs were decent, but the comet remained small unless cropped heavily.  It is winter in Maine and the cold had gotten the best of me, so I planned to shoot again Saturday night with the 400 F/4 SMC Takumar.

Prior to imaging comet Lovejoy Saturday night I anticipated the close conjunction of Venus and Mercury. This night they would be at their closest, within 0.7 degrees of each other.  Because my western horizon is blocked by trees I decided to drive down to Sorrento Harbor for a clear and more scenic setting.


Looking west at Sorrento Harbor


Like a pair of jewels, Venus and Mercury adorn the western sky

Watching the tandem planets as dusk deepened was incredible.  A cosmic perspective in an otherwise ordinary earthly scene.  I would have loved to watch the planetary pair sink to the horizon, but the cold air hastened my departure.  I took in one last view before packing it in.



I took a break for dinner once arriving home.  Skies were brilliantly clear and comet Lovejoy, obvious to the unaided eye was also noticeably higher than the previous night.  I managed to get the camera and lens arrangement mounted in short order.  After a few test exposures for framing and focus, I shut off the camera and went inside to warm up and the camera to cool down.  Once I had warmed up, it was time to take some images.


C/2014 Q2 Lovejoy


I spent about an hour performing about a dozen images.  While guiding one image I saw a satellite pass my field of view in the guiding eyepiece.  After reviewing the image I was delighted to find it had  passed right straight into the comets tail and through the center of the coma!  It felt like one of those Heaven's Gate Hale-Bopp moments.  Thoughts of posting the image on crank websites filled my mind for a moment, but I know there are people that amazingly take that stuff seriously. The thought of people taking their own lives influenced by such an image sobered me.  

Ultimately, the next to last image was the keeper from the night's session.  The stars are trailed as I had guided on the coma for the six minute exposure with the 400 at f/6.7 and ISO 1600.

Lovejoy is not an extravagant comet, indeed it reminded me of periodic comet Halley in it's 1986 appearance, but it is nice to see a decent comet show up in an easy see location in the sky.  








Friday, January 2, 2015

Happy New Year



Oh to get out of bed in the morning.  It's cold outside.  It's twilight time - dawn upon the new year. Get the Keurig going and try to find some clothes in the dark without waking the spouse.   It's actually not too bad, 20's this morning and no wind.  Nice!  I can see some clouds out the living room window to the southwest drifting east, might be worth a quick trip to the pond after all.  One cup of coffee down, grab the camera bag and out the door.

A week ago the pond was completely open and not one trace of ice, the recent cold snap should have created a nice layer by now.  Flanders Pond is just north of my home and in about five minutes trekking along a camp road we arrive.   There is ice!  It's smooth too!  About an inch or so thick.  I check it with a light step.  No problem.  The sky is brightening and high clouds to the east are illuminating with golden light.  

I reach inside the bag and get the K-5 and compose about a dozen different shots as the sky changes. I'm awestruck!   Within ten minutes, the magic moment arrives.  

Yea this was definitely better than wasting the dawn on my second cup and the news on the tube.



Sunrise Upon The New Year

Happy new year.  May you all get to lose some sleep and be glad you did.

JC

Saturday, July 26, 2014

Selected Regions of The Milky Way

In my previous post I wrote of my project to photograph selected areas of the Milky Way based on the original idea that Edward Emerson Barnard proposed and implemented on the summit of Mount Wilson in 1905.

I am glad to say that the first round was successful.  I spent several hours shooting the Milky Way from my home in Maine during the dark hours of  June 21st through July 1st.  I lost much sleep and had a few difficult days at work due to the late hour required on these summer evenings / mornings. In the end it was worth it.

I performed several test frames to get perfect infinity focus then dove into the lonely hours of exposing and guiding.  Dodging mosquitoes to my person and fireflies from the exposing film, it was a feat of labor and determination.  The frames below are the fruit of those labors.

Of technical note, all exposures ran about 40-50 minutes at apertures of f/4.8 and f/5.6.  A Tiffen Haze filter was installed in the tail end filter holder on the 400mm f/4 SMC Takumar to reduce the secondary spectrum common on these conventional glass lenses.  Exposures with and without the filter was dramatic.  Star images were much tighter even though overall the filter may reduce contrast and overall sharpness.  Some reflections were noted but were rather minor.  Fuji Neopan Acros was used for image acquisition.  Chosen due to its exemplary reciprocity characteristics and fine grain.  The films were custom processed in Xtol developer by Color Services in Needham Massachusetts.

Post processing was done by converting the original negatives to digital files via an Epson V600 scanner.  Adjustments to levels and curves were completed with Adobe Photoshop.



This image portrays the individual frames below against the wider field



Messier 22 Region in Sagittarius


The Scutum Star Cloud



The Small Sagittarius Star Cloud



The Dark Nebulae in Ophiuchus


The Great Sagittarius Star Cloud

The Dark Lanes in Ophiuchus


The Southern Scutum Star Cloud

There were a few more images but I have yet to work them up for posting.  So happy to be able to share the results with you and produce at least one more time a portfolio of images captured by traditional means.  The time spent under the stars, manually correcting the guiding along the way and taking in the quiet nights allowed me to capture, albeit imperfectly, the spirit of the great E.E. Barnard.  











Friday, July 4, 2014

Recapturing E.E. Barnard's Legacy



The Father of Milky Way photography, Edward Emerson Barnard systematically photographed the Milky Way on what was the yet to be developed Mount Wilson in 1905.  The images taken that year were to be published in A Photographic Atlas of Selected Regions of The Milky Way.  This seminal work was a reference for decades and still provides inspiration to wide-field astrophotographers today.

Barnard recalls how the project got started.

"Through the interest and courtesy of Professor George E. Hale and the generosity of Mr. John D.
Hooker, of Los Angeles, I spent the spring and summer of 1905 in photographic work at the Solar Observatory of the Carnegie Institution on Mount Wilson, California. Mr. Hooker’s generous grant
made it possible to transport the Bruce telescope to Mount Wilson, where it was installed from
February until September, 1905, in a temporary wooden structure, from which the roof could be slid
off, giving an unbroken view of the sky. The altitude of the station was about 5,900 feet, above the
sea, and its latitude 34°13 .  The main object of this expedition to Mount Wilson wasto secure
the best possible photographs of the Milky Way as far south as the latitude would permit."

The Bruce Observatory with roll-off roof  featuring the 10" Photographic Telescope in 1905.

University of Chicago Photographic Archive, [ apf6-01621r], Special Collections Research Center, University of Chicago Library.

The photographic instrument was four instruments in one.  The 10-inch and 6.25-inch photographic telescopes, and a 3.5 -inch doublet and lantern lens as well as a guiding telescope. First exposures began on January 27th and ended in September of that same year, 1905.  Barnard spent almost the whole period on the mountain, except on one occasion to go into town to obtain the services of a notary and barber.   Barnard was famous for being a workaholic at the telescope, possibly due to his drive to be the second to none in his capabilities.  Long gone were his childhood days of poverty and the opportunity to be the best was not wasted.

Barnard at the helm of the Bruce instrument.

University of Chicago Photographic Archive, apf6-04469r, Special Collections Research Center, University of Chicago Library.





Plate 27- The Great Sagittarius Star Cloud 

July 6.815 1905
3 Hour 58 Minute exposure
Barnard's exposures of the Milky Way typically lasted 4 to 5 hours.  Barnard would correct the instruments guiding as the cameras panned across the open landscape counteracting the earth's motion.  The long hours of photography "Would have horrified any medical man" Walter S. Adams recalled in his recollection of Barnard's sleepless nights, "Sleep he considered a sheer waste of time, and for long intervals would forget it altogether. After observing until midnight, he would drink a large quantity of coffee, work the remainder of the night, develop his photographs, and then join the solar observers at breakfast. The morning he would spend in washing his plates, which was done by successive changes of water, since running water was not yet available. On rare occasions he would take a nap in the afternoon, but usually he would spend the time around his telescope. He liked to sing, although far from gifted in the art, but reserved his singing for times when he was feeling particularly cheerful. Accordingly, when we at the Monastery heard various doleful sounds coming down the slope from the direction of the Bruce telescope, we knew that everything was going well and that the seeing was good."

My admiration of Barnard's work hearkens back to my younger days when I was starting out in astrophotography.  Those then famous black and white images of the Milky Way were the stuff of dreams to a young astronomer wanting to explore the night sky.  It seemed any photographic reference to the Milky Way's structure turned to Barnard's work as they were still the standard reference on the subject, in spite of other surveys such as POSS and POSS-II being more recent but much narrower photographic fields.

Fast forward to 2014.  How was I to symbolically and in a very real way reproduce some of Barnard's efforts?  In 2011, I performed some tests with Fuji Acros, a black and white negative film that has the best reciprocity characteristics of any film in history.  It showed itself to be very capable of long exposure work, but lacked the red sensitivity often desired for astronomical use.  The lack of red sensitivity does not hinder star cloud and dark nebulae photography however.  I performed many successful exposures with various focal length lenses, with the 200mm and 300mm focal length lens coming close to the Barnard photos in field size and depth, but I would get much closer and a similar field size with a 400mm lens.

Guiding analog cameras under a dark sky and monitoring the guide star in a double cross-hair reticle eyepiece, making small corrections in the clock drive and for atmospherics reflects similarly what Barnard used for techniques.  Manual guiding is something that adds to the experience as the pioneers such as Barnard used this laborious technique to get the job done.  Making these images is so much more than shooting film to replicate the historical work, but the experiences under the night using very basic technology.

Further testing in 2012 revealed remarkable image capability of medium format film and camera system.


Messier 8 Region @ 200mm

Southern Ophiuchus @ 200mm

The Scutum Star Cloud @ 200mm

The 400mm f/4 medium format lens produces a similar field size (8x10 degrees) to Mount Wilson's Bruce Photographic Telescope.  I was not to use glass plates 14x18 inches like the Bruce instrument used, but a relatively small piece of photographic film 2.25 x 2.75 inches in size.

In June of 2014, I had acquired and mounted such a lens for the project.  The 400mm f/4 Super-Multi-Coated TAKUMAR for the Pentax 67 was dubbed, the "Mini-Bruce". 

The 400mm f/4 "Mini-Bruce" Astrograph rides atop my classic 8" Meade


I built a personal observatory, much like Barnard's 1905 Mount Wilson setup in 2003.  It has good exposure to the southern sky, despite my 44.5 degree north Latitude. This gives me access to most of the sky Barnard had.  Flanders Pond Observatory has been a useful photo-visual laboratory.  Its showing its age and will be needing maintenance of replacement soon.  If I can get just a few more years out of it!

Inside the roll off roof, the "Mini-Bruce" ready for action on a clear dark night.

The summer weather will determine just how successful this project turns out to be.  I am hopeful.  To fall in the footsteps of the master is a privilege.  I would so love to have met Mr. Barnard.  His story and images have been an inspiration for many but, I consider myself to be the number one fan of the man from Tennessee.



Permissions for reproduction of images of Plate 27 as follows: 

Georgia Institute of Technology Library and Information Center, Great Star Clouds in Sagittarius - 2, Plate 27, Edward Emerson Barnard's Photographic Atlas of Selected Regions of the Milky Way, June 2004, Georgia Institute of Technology, June 14, 2014 http://www.library.gatech.edu/Barnard_Project_W/PDF/plate27.pdf