Astronomy and astrophotography are journeys
This journey has no destination. It is as limitless as space. Only you place limits on what you know, and what you seek.
My journey began as a child. In school I was drawn to books with lots of photographs about space and the planets. I loved the artist's conceptions of what our neighbors in the solar system might look like were we able to stand on their surfaces.
The Apollo space program held my attention. I loved it when class was interrupted by the TV being wheeled out and we watched launches, space walks and images of the moon as our astronauts orbited and made preparations to land. I will never forget that hot July night when my father woke me from sleep to watch Neil Armstrong take that monumental first step on another world. A major highlight was seeing, and touching the Apollo 11 command module when it came to Maine on its national tour.
I recall my very first (and so far only) telescope. It had a cheap alt-azimuth mount and was a study in frustration! Yet I managed to catch a glimpse of what lay beyond the terrestrial view. I wish I had explored astronomy further, but growing up, school, and of course girls stole my attention away. Then marriage and raising a family took priority.
Well, now my kids are grown and have kids. Time to return to the journey, and pick up where I left off.
I just thought I would share a bit about my journey. Maybe others would like to share. Photography and astronomy are more than equipment. More than technique. It's about passion and imagination.
I will steal a little thunder from Microsoft.
Where do you want to go today?
#1. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 0
jrp Charter MemberThu 23-Aug-12 11:48 PM
I am always surprised at how much we, Nikonians, share or have in common.
In this particular case your words reminded me as a 10 year old boy building his own little moonscape with white sand and three astronauts in transparent helmets, always playing with it before going to sleep.
And that was in 1951.
Many years later a bunch of MBA students gathered in our efficiency apartment with eyes glued to three televisions to watch in awe all three major network transmissions of the first moon landing.
I have a picture of that.
A few years forward I found out that the conglomerate I worked for wanted to build a museum. I managed to get that project assigned to me and switched that project into a Planetarium. Interestingly enough, with a team who happened to be all Star Trekkers.
My wife was a founding member of the Astronomy Society, made possible with such fully equipped planetarium.
Photography? That did not go that well. While in college I got a Cambron f/6.3 to shoot the moon and ruined quite a few hundreds of feet of film in the effort. I may still have that lens in a closet. But it helped me to garner more understanding in the long quest for the perfect tripod.
The crave to go and see beyond remains there.
Thank you for being with us. It is more than a pleasure to present you with this new forum.
Have a great time :-)
JRP (Founder & Administrator. Mainly at the north-eastern Mexican desert) Gallery, Brief Love Story
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#3. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 1
Sat 25-Aug-12 11:02 PM
I just saw a new article posted very recently to ABC news that Neil Armstrong has passed away. Typical of the way he lived his life post-Apollo, the article was very understated and did not even mention a date.
He touched many of our lives in ways few could ever do.
He'll be missed by all of us that remember that late night broadcast so many years ago now, as well as the follow up interviews he did over the years.
my Nikonians gallery.
#2. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 0
#4. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 2
Sun 26-Aug-12 08:14 PM
I think the aliens there scared them off lol!
Well, I am taking some baby steps moving into astronomy and astrophotography. I am not going to rush out and get a scope yet. Two reasons. 1. Not enough funds yet to get a decent scope. 2. Going the binocular route first.
I just bought a pair of Meade 9x63 Astronomy binoculars. Not bad at $100 and they get some good reviews. No, you can't do astrophotography with those. But you can learn and see a lot with binoculars and from all the reading I've done, that is the recommended route for beginners. I want to do this right and if it means waiting for the right telescope, then wait I shall. I can use my Slik tripod and with a binocular adapter, I can begin my journey around the solar system and peek at star clusters.
When I feel ready to take a stab at using my camera, I can do so on the club's scope.
Binoculars are a good thing to have in your arsenal of observing tools, so I plan to keep a good pair permanently.
So where are you on this journey?
#5. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 4
Wed 05-Sep-12 05:58 PM
Well, the Meades didn't pan out, so returning them. Good binoculars, they just don't fit my eyes. I have wide set eyes. I just ordered a pair of Oberwerk 10.5x70's. These have a wider IPD, which is short for Interpupillary Distance, which is the measurement of the distance between the pupils of your eyes.
I had to pony up more money. $419 with tripod mount and shipping. Good thing I sold some of my old lenses. Should be here next week and I am keeping my fingers crossed (not my eyes) that these will work well for me.
#6. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 0
Ah... You are so right !
It started when I was a child, with the chance to follow the inauguration of the Planetarium of Calcutta (Kolkata), one of the biggest at that time. My big brother was a fighter pilot, I wanted to be a Cosmonaut...
I started drawing spaceships and rockets and followed through my brother the progress of rocketry ! I looked at stars at night and learned my way through the constellations by reading Camille Flammarion.
One day, near the end of july, I was outside, with dozen of thousands people, looking at the moon while hearing the radio... Sort of holding my breath with the entire planet!
Some times later I had the luck to have a dinner with Leonov who was in Paris.
Further in time I got myself a 5" newton and tried photography (still have the nikon mount adapters and the newton), saturn was so much smaller and dull then when I was looking at it, the moon was moving too fast, as I didn't have a motorized mount. Still with the brand new coolpix 990 I started again, for fun !
But with three children it's not an easy task to go in deserted places for holidays to find a black sky, I had to surrender
I will try again, one of these days ! But this time, I'll start with a photo-mount, motorized and computerized, using my primes... I'll look for the 'scopes after, in a second phase when I'll know where to base it...
So I'm happy to see this forum and the wonderful pictures shown here...
"Un photographe, finalement, c'est quelqu'un comme les autres, mais qui prend des photos." - Man Ray
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#7. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 0
Bought a pair of Nikon 7x50 binoculars for the night sky. Then I picked up an inexpensive Meade ETX-60 and a couple of eyepieces and a barlow.
When its warm out, and fairly late in the night, I like to lay in the chaise lounge chair and see if I can catch satellites as they streak across the sky. Haven't tried photography any of the annual meteor showers, though I think I will have to try that out sometime soon.
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#8. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 7
Thu 13-Sep-12 01:16 PM | edited Thu 13-Sep-12 01:17 PM by gbowen
I just bought a pair of Oberwerk 10.5x70s and wow, these babies are so sharp and clear! Heavy though, weighing in at 5 lbs. I had to return the Meades I bought recently. Just were not a good fit for my eyes.
I am working on getting a new tripod setup. My Slik just isn't up to the weight, plus the ballhead is better for photography than binocular work, so I am getting a video panhead and a taller tripod. Much easier to control and very smooth, also easier on my back and neck for observing objects directly overhead.
I am in no hurry to get a scope yet. I want my first experience with astrophotography to be memorable, with as little frustration as possible. A good scope goes a long way toward initial satisfaction. Unfortunately good scopes cost a lot of money, so I am saving and doing research to find the best one to suit my needs.
Now is the time to learn the sky. I have purchased a planisphere, a red lens flashlight, and a star atlas. I have yet to find a good observation spot with dark skies and close to home, but I will. I am hoping around Christmas to get my first real telescope and start assembling all I need to capture images.
I am taking the first steps in my journey. I look forward to the adventure!
#9. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 7
Fri 14-Sep-12 02:06 PM
>Bought a pair of Nikon 7x50 binoculars for the night sky.
>Then I picked up an inexpensive Meade ETX-60 and a couple of
>eyepieces and a barlow.
I have been considering an ETX scope, either the 90 Maksutov-Cassegrain or 80mm refractor, with the refractor being reasonably cheap at under $250. Both are suitable for basic astrophotography, though neither can support long exposure times. Mostly useful for sun/moon/planetary photography, which is where you would start anyway. I think the moon will keep me busy for quite awhile.
I have been seeing a lot of moon and sun photos being made with the 600 f4 and it kind of makes me scratch my head. Unless you use that lens for other things, like wildlife, you can get a real kicker of a scope for a quarter of the cost. Heck, you can get two or three different types for what you pay for the 600. Can you say Takahashi? Just my 2 cents worth.
#10. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 9
Thu 20-Sep-12 04:28 PM
After some research I have come to the conclusion that AP is not where my journey lies. Several reasons, but 3 was all I needed to decide.
Reason #1. Cost. I read several forum posts on an astronomy website mentioning how expensive it is, one person saying that $2,500 was a modest cost of doing AP. I cringe to see what the generous cost is!
Reason #2. Learning curve is quite steep. I do not possess that kind of patience.
Reason #3. I want to have fun and not worry if my image is any good or not. I do not want to prove anything to anybody. I just want a fun relaxing hobby to enjoy and pass that enjoyment on to my grandkids.
I know many of you have made the jump and will probably say it wasn't that bad. But, each of us must pursue their own joy, and to me AP does not sound joyful.
So while I won't be sticking my camera on a telescope, that does not mean I cannot do star trails and such. That sounds like fun to me.
Clear skies everyone!
#11. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 10
avm247 Charter MemberThu 20-Sep-12 05:11 PM
I find astronomy to be as inexpensive or as expensive as you want it to be.
I remember a cousin came home one day with his VW Beetle filled with a 10-12" reflector telescope and equatorial mount. Not so good seeing in Los Angeles in the 80s but it was still fun. I wonder if he still has it...
I also want to use my Coolpix 4500 to try and take some astro pics from my Meade ETX60. Just haven't done it yet.
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The important things in life are simple; the simple things are hard.
#12. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 11
Thu 20-Sep-12 06:27 PM
>I find astronomy to be as inexpensive or as expensive as you
>want it to be.
Just like most things. I look for used bargains. I have a decent Celestron CG4 EQ mount and tripod on the way. Comes with the motor drive, and in great condition for $100 less than new for the identical rig. Celestron has a great deal going for their C90 astronomical spotting scope, which is a 90mm Maksutov-Cassegrain and B&H sells it for the crazy price of $149. It gets great reviews, so I ordered that and it arrives tomorrow, and the mount is due in Saturday. Sounds like a fun weekend ahead!
>I remember a cousin came home one day with his VW Beetle
>filled with a 10-12" reflector telescope and equatorial
>mount. Not so good seeing in Los Angeles in the 80s but it
>was still fun. I wonder if he still has it...
Sounds like quite a beast!
>I also want to use my Coolpix 4500 to try and take some astro
>pics from my Meade ETX60. Just haven't done it yet.
Ha, I am the king of procrastination. Just say yes, Your Lateness!
#13. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 11
Sat 22-Sep-12 04:52 AM
I did a fair amount of work with my Questar and Coolpix 990/995 cameras. Those cameras, and the 4500, have 28mm filter threads.
Scopetronix made a couple of eyepieces with matching 28mm threads. I have both the eyepieces (and a matching barlow). It made a very solid connection and simple mechanical connection, and formed a sort of eyepiece/afocal projection system for the Coolpix cameras.
my Nikonians gallery.
#14. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 9
>> I have been seeing a lot of moon and sun photos being made with the 600 f4 and it kind of makes me scratch my head. Unless you use that lens for other things, like wildlife, you can get a real kicker of a scope for a quarter of the cost. Heck, you can get two or three different types for what you pay for the 600. Can you say Takahashi? Just my 2 cents worth.
I suspect most people using that lens, or the fast 400 or 500mm lenses, are shooting wildlife and use the lens for astro work because they already own them.
If you priced out a high quality 6" astro refractor, you might find that the price difference isn't so high. You couldn't buy a 6" Tak for 1/4 the price of a 600/4 (if they made one).
For example, a 120mm (~5") Tak sells for $4700. A 6" refractor was historically a huge beast although modern refractors are shorter than their focal length, making them a little less unwieldy.
For astrophotography, speed is your friend. Astronomical refractors are not built as fast as f/4 and for that reason I think the fast photographic lenses are interesting. I've used my 500/4 for astro work although I don't have a proper mount for it.
The biggest problem with using fast photo lenses for astro work is that they have very little "back focus", making it maybe impossible to mount an eyepiece for visual work (or eyepiece projection).
Nikon made an eyepiece adapter years ago and they sell for several hundred dollars when you can find them. It came with an integrated 20mm eyepiece and I don't think it was possible to use other eyepieces. Because of the cost I never bought one. And it really needs a shorter focal length eyepiece for most visual work.
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#15. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 14
Sat 22-Sep-12 08:27 PM | edited Sat 22-Sep-12 08:30 PM by gbowen
Well, that point about cost is rather moot for me. No way I can spend 4K on anything (unless it has wheels and an engine)
I would rather spend less for a scope that is great for observing, but maybe not so great for AP. I would love to get either a 6" or an 8" SCT. Like most newbies to astronomy I had no idea that AP was so expensive and complicated. I think for me a blend is good. Star trails and meteor showers with a tripod mounted camera, and just observing planets, stars and DSOs with a scope.
Well here is my new setup. I got a good deal on a used motorized EQ mount, a Celestron Omni CG 4, and my little Celestron C90 Astro spotting scope. That mount is one solid beast. I can upgrade to something better by simply buying an optical tube assembly. Believe it or not, I only spent about $500 for the whole rig.
The nice part is I can do AP with that motor drive is I so choose to later on. I believe in future proofing.
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#16. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 15
Sun 23-Sep-12 09:31 AM
My point about the cost was simply that any comparisons in price need to compare similar (physical) aperture. Your 4x number would be more comparable to a 3-4" refractor. I figure a new fast photo lens is about 1.5 - 2x the cost of a new high quality refractor (very roughly), and part of that is the far more complex focusing of the photo lens, plus VR, and the other complexities. Each solution has its unique problems.
That setup will give you a good taste for astrophotography. I would figure on a max 8lb payload, to be conservative. If you load it heavily keep an eye on the condition of the nylon (?) gear(s). That would be the weak link of an EQ mount at that price point.
Here is an interesting link, with further links, on tune up and improvement issues with that mount. It will give you some idea of the issues others have faced.
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#17. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 16
Sun 23-Sep-12 01:52 PM | edited Sun 23-Sep-12 01:53 PM by gbowen
Thanks, Neil, I will check that out.
Oh wow, had my very first unofficial and private star party last night with my daughter and granddaughter. Actually moon party would be more accurate. That half moon was unbelievable in my eyepiece! The craters and mountains were in perfect relief. I swear I could see Neil Armstrong's footprints! I was wishing I had a camera adapter and my D7000 to capture it. The moon filled just about the whole frame, so it would have rivaled anything I've seen posted here.
The EQ mount took a bit of getting used to. I did not have the motor drive going. I don't know how to do the polar alignment yet, so I just winged it and used the manual controls. But it was fun and I was getting used to the unique movement of the mount. This is my very first equatorial mount and I had just received it that morning, so I figure I did pretty well considering. I like it a lot and I am seriously hooked!
I also had my Oberwerk 10.5x70 binoculars on my Slik tripod and what a joy they are. The moon was crisp and clear, though not at the same magnification obviously.
Last night had me reconsidering AP. It's one thing to sit at the computer and talk about it, quite another to be out there under the stars. My daughter actually tried to put her smartphone up to the eyepiece and do a little afocal photography. Didn't work too well. I saw somewhere online that they make holders for just such a setup. Amazing. All in good time. The sky really is the limit.
Meantime I am going to have fun!
Clear Skies everyone!
#18. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 17
Tue 25-Sep-12 08:33 AM | edited Tue 25-Sep-12 09:44 AM by nrothschild
I think you are right to take the astrophotography part slowly. In particular you want to get accustomed to working all those controls in the dark before adding a camera . I use a 9V LED flashlight that has switchable red and white lights. I use red when I'm trying to maintain dark adapted eyes.
If you have not done so already you want to learn how to polar align the mount. You set the optical lens to 90 degrees declination such that the optical axis is parallel to the direction the mount is pointing.
Then, leaving Dec locked down at 90 degrees, aim at the north star (Polaris) and center it.
With Polaris centered in the scope view, you should be able to spin the right ascension axis without Polaris moving (much). If Polaris scribes a big circle or goes out of view then either the mount has a mechanical misalignment or more likely the Dec circle is out of alignment. Usually there is s screw somewhere to loosen the dec circle in order to align it properly.
You can test the alignment of the dec circle, day or night, by pointing the mount at anything, at any altitude, with the optical tube set to 90 degrees dec. Most people just do this test while they are aligning the mount.
Polaris is actually at 89.25 degrees Dec, not 90. That error matters if you are doing very long exposures. For visual observing I find a simple Polaris alignment to be more than accurate enough. THat is also plenty accurate for relatively fast shutter speed moon exposures or any other exposures up to a couple seconds duration. Beyond that and you will want to find tune the alignment. But that is in the future.
Despite your protestations to the contrary, you are a photographer and you will get the bug to try to shoot some images .
There are two methods- prime focus and eyepiece projection.
Prime focus couples the camera (without lens attached) to the optical tube giving you, in this case, about 1250 - 1400mm focal length depsnding on the length of the attachment plumbing.
Your focal ratio with the C90 is rated at f/14 (the same as my 89mm Questar). The effective focal ratio, or T/Ratio, will be more like f/18 or so and that is quite challenging to deal with. LiveView is the best solution. The camera's optical viewfinder will be quite dark and grainy.
I would try this first because it is relatively much easier...
Eyepiece projection attaches the camera (again without lens if it has an interchangeable lens mount) behind a standard visual eyepiece. The effective focal length can be computed by a formula and varies based on the dimensions of the distance of the film plane to the eyepiece and especially eyepiece focal length. But generally speaking you are then working f/20 to f/40 or smaller. This makes prime focus look easy .
Celestron probably sells the plumbing needed to adapt a Nikon DSLR to the scope. The spec suggests that the back is threaded with T threads, in which case there are also many third party solutions available.
In general, you need a Nikon mount adapter, which is basically a lens mount with integral T threads. Then you need a short tube to attach to the back of the scope and the camera mount adapter. Nikon adapters are basically Ai compatible lens mounts. The camera will "think" it has a standard manual focus lens attached.
edit: after downloading the manual, I see that the back of the C90 has an "extension tube" integrated into the back, so all you need is a Nikon lens mount adapter with female T-Threads. Some scopes would have female T threads directly on the back, without that approx 1" extension tube integral to the C90.
I set my camera non-cpu lens setting to about 1400mm and about f/20, just so I know that I was shooting prime focus. And these numbers are specific to your C90 and my Questar, which have the about the same optical formula.
At prime focus you can fit a first or third quarter moon into a DX frame but not a full moon. It's that tight. On FX even a full moon is a very comfortable fit.
Astronomers use "Barlow lenses" as focal length multipliers, similar to how we use TC's. I would suspect that a Nikon "E" TC, such as TC14E-II, would not mount to the typical Nikon adapter but an older TC such as a TC14B should.
Most Barlow lenses are threaded to attach to a visual eyepiece. You may find one that couples to T-threads. A TC or barlow is an intermediate step between prime focus and eyepiece projection (and is just a slight variation on a standard prime focus setup).
A 2x barlow would take you to about 2600-2800mm or so and you would find that very challenging.
I use a Questar 2x barlow, which was machined to thread into their extension tube and adapters. It's an enginious system but very expensive and uses "P" threads. I'm not sure what is commercially available now in the way of barlows and plumbing to set up for prime focus. Celestron probably makes the parts. Also Meade, and both probably use T threads so Meade adapters are probably compatible withthe C90 (but verify that).
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#19. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 18
Tue 25-Sep-12 08:52 AM
A followup on Polaris:
Polaris is actually a binary star. The companion is relatively widely separated, at 18". That is more than enough separation at any magnification you might use with a 1200mm scope.
However, Polaris is magnitude 2.0 but the companion is magnitude 9.0, so the companion is 7 magnitudes dimmer than the main star we all know. As such I think it can be very challenging in a 3.5" scope. It is far easier to split in my 7" Questar.
It is especially difficult to split when typically setting up alignment as soon as Polaris pops into view in the late dusk.
At my home I have to sight Polaris through trees, if I can see it at all. I try to find the companion in order to make sure I am sighting the right star .
The astronomical position angle of the companion, relative to the main star, is about 220 degrees. However, the relative position you see depends on the time and the season because the companion rotates around the primary once a day, similar to how all the other northern stars appear to rotate in a circle around Polaris.
It is helpful to know the physical position angle of the companion (as it appears in your optics, which varies depending on the configuration!) in the various seasons at early evening time in order to get a sanity check on the observation.
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#20. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 19
Wed 26-Sep-12 12:48 PM
Wow, that's a lot to digest! I do have the adapter on the way and I am hoping to play with it during full moon this weekend, however, long range weather forecasting does not look good. May have to catch the moon during waning gibbous or third quarter, which is actually better.
I have yet to play with polar alignment and I know I need to. Thanks for the detailed instructions. I will try that as soon as possible.
The moon sold me on trying to do some AP. I am going to keep it as simple as possible. I am just going to concentrate on the moon for now and get the technique down before trying any other planets. I still have a lot to learn about the sky and how to locate items of interest.
All in good time. It will come.
Thanks again, Neil.
#21. "RE: Astronomy and astrophotography are journeys" | In response to Reply # 20
Wed 26-Sep-12 05:57 PM
The 3rd quarter moon transits the meridian (it is due south and highest in the sky) at sunrise. It is the most favorable phase now so I think that is a great target to shoot for if you like to do these things in the very early am. Each day thereafter the moon is increasingly lower at dawn, so a few days after 3rd quarter it is no longer a very ideal target although it is so favorable now that that helps.
The full moon is good practice but I suspect you may not like the results (I never do with high res optics, and certainly not without a lot of post processing). If the full moon is very soft it may not be you or the gear so it is a bad test. IOW, don't get discouraged if you don't like the results of the full moon. About 4 days after the full moon you start to regain a decent terminator to judge image quality.
You are correct- you do not want to even think about the planets until the moon is relative child's play and you can do it without thinking too much about it.
When you do take on the planets, do some research into "the hat trick". You use a piece of cardboard in front of the lens to start and stop the exposure, at least 5 seconds or so after tripping the camera shutter in bulb mode. That allows you to effectively do a "shutter lockup" in addition to a mirror lockup. Shutter vibration at planet resolutions can be a tough problem.
The problem with the hat trick is that it is difficult to do at shutter speeds faster than a half second or so, and increasingly difficult to do in a consistent manner (maintaining some sort of consistent shutter speed) as the shutter speed increases.
And of course, in this case your camera EXIF shutter speed will be meaningless. You will then be bombed back to the film age
With fast shutter speeds I have had a problem with the rapid cardboard movement creating air currents that are a cure worse than the problem it is trying to solve. For that reason I don't do it very often.
My cardboard shutter is a big piece of very heavy black poster board or maybe mat board and has a rectangle cutout about 6" in each dimension, sized to be comfortable with my 3.5" Questar.
The board needs to be long enough that you can start and stop the exposure with the lens covered by a closed section of the cardboard, without overshoot or undershoot, and etc. Mine is probably almost 20" long, just to make that part easier and more goof-proof.
It needs to be wide enough that you are sure the lens fully fits inside the cutout as you do the swipe.
I built mine back in the film days when I never knew what I did wrong until the film came back or I developed it the next day or so. And after the fact it was difficult to relate the film image to what I had actually done (in terms of swiping speed and technique) a day or a week ago.
It is much easier now to figure all this out and get a good tempo since we get instant feedback and can more easily tweak our way into the best technique.
I cut another piece of board about 2-3" wider in each dimension than the cutout, or about 8-9" square. I attached velcro to the main shutter board and the "adjustable shutter" such that I can quickly adjust the size of the slit.
For a high speed exposure I might only leave 1" or so of the slit open. The idea is that a narrower slit allows for faster exposures with a slower draw of the shutter board. Very similar to how camera shutters work when they are moving faster than the flash sync speed - the shutter forms a slit and is never fully opened.
For multi-second exposures you remove the cutout and stop the board for the appointed time with the lens fully exposed. For very long exposures you fully cover the slit with the cutout, and just drop the board to start and then raise it back in position when the exposure should end, using a watch, stopwatch or timer. I used a digital timer that counts down and beeps when my set time is completed. You need to manage the shutter board one-handed as the other hand starts the timer.
I have read claims that you can achieve a shutter speed of about 1/125s using this type of shutter but I was never successful. Maybe I just didn't practice enough. At that point in time I gave up DSLR work on the planets in favor of a shutter-less webcam, which solved that problem, plus the seeing. But hugely added to the overall complexity of things, especially post-processing.
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