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Subject: "D90 on telescope DU-UH..." Previous topic | Next topic
patrick_g Registered since 04th May 2012Fri 04-May-12 03:11 AM
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"D90 on telescope DU-UH..."


US
          

I have very little operating time on my D90 and I am stumped and found no help in the manual. I am about to drive several hundred miles for a photo op of the May 20 annular eclipse. I have purchased a solar filter for my 8 inch telescope and adapters to put my D90 at prime focus (in place of an eyepiece),i.e. no lens attached to the camera, using telescope for lens. OK I know I must focus manually (no problem) but how do I get the shutter to operate? (my big problem) Hopefully there is a way to get the camera to make an automatically exposed shot, ignoring the lack of a Nikon lens mounted to it.

I'd really appreciate some help with this.

Patrick

  

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Reply message RE: D90 on telescope DU-UH...
aolander Silver Member
04th May 2012
1
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patrick_g
04th May 2012
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MEMcD Moderator
04th May 2012
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patrick_g
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MEMcD Moderator
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aolander Silver Member
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nrothschild Silver Member
04th May 2012
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nrothschild Silver Member
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aolander Silver Member Nikonian since 15th Sep 2006Fri 04-May-12 01:18 PM
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#1. "RE: D90 on telescope DU-UH..."
In response to Reply # 0
Fri 04-May-12 01:20 PM by aolander

Nevis, US
          

Since the D90 cannot operate with non-CPU lenses, I don't think any auto or semi-automatic mode will work. On my D300 (which can operate with non-CPU lenses) without a lens attached in aperture priority mode, it operates as if there is a non-CPU lens attached set at the widest aperture of the last manual lens I used. I'm not sure how accurate the exposures would be, though.

I think you may be out of luck for an auto-exposure, but you can shoot in manual and check the histogram and monitor image for exposure accuracy (and bracket). There are probably a number of tutorials on shooting an eclipse if you search.

Alan

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patrick_g Registered since 04th May 2012Fri 04-May-12 01:41 PM
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#2. "RE: D90 on telescope DU-UH..."
In response to Reply # 1


US
          

Thanks for info. Boy am I a disappointed dummy. Can I get it to take pix if I set everything manually or does it have to have the automated lens installed to get an exposure?

Life was so simple with manual film type SLRs. Well, OK not simple but I was good enough with that equipment. I don't want to be reduced to an OM-1 with film... to shoot nan eclipse picture. The sun filter for my 8 inch telescope wasn't cheap and now it is not too useful.

Patrick

  

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MEMcD Moderator In depth knowledge in various areas Nikonian since 24th Dec 2007Fri 04-May-12 02:32 PM
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#3. "RE: D90 on telescope DU-UH..."
In response to Reply # 2
Fri 04-May-12 02:34 PM by MEMcD

US
          

Hi Patrick,

Welcome to Nikonians!

>Can I get it
>to take pix if I set everything manually or does it have to
>have the automated lens installed to get an exposure?

Yes! If you set the camera in Manual exposure mode with Manual ISO you will be able to capture images with the camera mounted on your telescope though the D90 light meter will not work without a CPU lens mounted on the body.
As Alan wrote above, you can use the Trial and Error method and the Histogram to set the correct exposure.
For future reference the D7000 and above bodies have metering capability when used with non-CPU lenses.
Good Luck and Enjoy your Nikons!



Best Regards,
Marty

  

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patrick_g Registered since 04th May 2012Fri 04-May-12 03:26 PM
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#4. "RE: D90 on telescope DU-UH..."
In response to Reply # 3


US
          

Marty, thank you. I just got off the phone to camera dept of a store to see if I could get decent 35mm film as a fall back position with Nikon SLR film camera or my old standby OM-1 totally manual camera which I have mated to telescope for decades.

I'll put on the solar filter and make some trials to get an idea.

Thanks for info. There is hope for me yet, maybe.

Patrick

  

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MEMcD Moderator In depth knowledge in various areas Nikonian since 24th Dec 2007Fri 04-May-12 03:38 PM
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#5. "RE: D90 on telescope DU-UH..."
In response to Reply # 4


US
          

Hi Patrick,

Your experience with film should give you a place to start with your settings, even though you are using a new filter.
I assume the filter will reduce the light passing through the telescope significantly which may make it difficult to focus as well. I know a 10 stop ND filter can make focusing extremely difficult and I assume that your solar filter is significantly darker than a 10 stop ND filter. Of course you have the advantage of a very bright subject which may make this a non-issue.
Good Luck and Enjoy your Nikons!

Best Regards,
Marty

  

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aolander Silver Member Nikonian since 15th Sep 2006Fri 04-May-12 04:16 PM
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#6. "RE: D90 on telescope DU-UH..."
In response to Reply # 0


Nevis, US
          

If you're experienced with a manual film camera, using your D90 in manual mode, even though there is no metering, should be no problem. At least with digital, you can review your exposure immediately and retake if necessary. Bracketing will help, too.

Alan

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nrothschild Silver Member Neil is an expert in several areas, including camera support Nikonian since 25th Jul 2004Fri 04-May-12 06:24 PM
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#7. "RE: D90 on telescope DU-UH..."
In response to Reply # 0
Fri 04-May-12 06:25 PM by nrothschild

US
          

Having shot a full solar eclipse, I would suggest practicing as much as possible before the Big Day. In particular, with an 8" scope which I assume is f/10 and 2000mm, you will need to practice finding the sun. Use a sheet of white paper, held behind the camera. When the shadow of the tube of the scope is round (and not oval), you should have the sun. This will be your biggest challenge, believe it or not, not exposure or focusing. Practice, practice, practice. If your scope is not on an equatorial mount and properly aligned you will need to practice chasing the sun.

With the solar filter attached, you can shoot the sun any time it is visible. You might even pick up some sunspots if they are present.

The eclipse exposure should be the same as the full sun. There will just be less sun during the eclipse . But the annulus that is visible should be about the same exposure as the normal sun. If high clouds are present then you will need to adjust but then you are shooting digital now, not film sot hat's easy

With a typical solar filter the brightness of the sun will be sufficient to focus. You will figure that out on your practice sessions prior to the Big Day.

On eclipse day you will want your focus and exposure set before the eclipse starts so that then you are just a monkey, pushing the shutter release on the remote from time to time . Trust me, the monkey approach is best because you will be otherwise very involved with what is generally happening. KISS and practice.

_________________________________
Neil


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nrothschild Silver Member Neil is an expert in several areas, including camera support Nikonian since 25th Jul 2004Fri 04-May-12 06:38 PM
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#8. "RE: D90 on telescope DU-UH..."
In response to Reply # 7


US
          

A cautionary note: if, during the eclipse, you lose the sun, DO NOT and I really mean DO NOT try to visually line up the scope by sighting the optical tube. If the eclipse is well under way, or especially in the annular phase, the sun may not look bright but the IR and UV coming from the thin annulus is very dangerous. You don't want to get permanent retinal burns from this. Retinal burns from partial eclipses typically occur with no pain or discomfort suffered while getting them. The damage sets in after it's all over and you only think you "cheated death".

This is why I am stressing that you practice ahead of time, and try to pre-plan these things as best you can. If you can do this in the blinding glare of the normal sun you can do this safely during the clipse using the same general precautions.

Thinking some more, you may want to try to source some solar filter material for your finder scope if you have not already done so. A right angle finder would be safer. Aligning a scope during an eclipse with a straight-through finder (with solar filter installed) entails some tricky work to do it safely, assuming that can be done safely at all. The temptation to "peek and cheat" is overwhelming.

Unless there are large sunspots that might be imaged, it may actually be easier, and it is far safer to just use a shorter lens such as a standard photo lens of around 300mm or so. You would, of course, need a solar filter for that lens. Aside from sunspots there is not much additional detail to be had from a very long focus scope. It just makes the finding more difficult and dangerous, and generally requires more attention during the Big Event when you might also want to just enjoy it.

There is some excellent general advice on viewing, photography and general eclipse procedures here. He literally writes the books on solar eclipses (NASA's guides)


_________________________________
Neil


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patrick_g Registered since 04th May 2012Fri 04-May-12 07:00 PM
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#9. "RE: D90 on telescope DU-UH..."
In response to Reply # 7


US
          

I totally agree on the practice commentary. I have shot comets and lunar eclipses but only recently got a solar filter (for this eclipse and the planetary transit on the 5th of June (I think.) Practice is what surfaced my problem. In "M" mode the shutter fires. I focused the scope on a terrestrial scene looking through the D90 view finder and adjusting the telescope focus. I took a few shots and all are black. Not there yet but not giving up either.

Part of my problem is not using the camera enough to know how to use it. Back to the manual...

Patrick

  

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nrothschild Silver Member Neil is an expert in several areas, including camera support Nikonian since 25th Jul 2004Fri 04-May-12 07:44 PM
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#10. "RE: D90 on telescope DU-UH..."
In response to Reply # 9
Fri 04-May-12 10:18 PM by nrothschild

US
          

Hi Patrick,

I figured (hoped ) you knew your away around the scope but had not imaged the sun yet.

I had an idle thought that leads to a question...

You are aware that, at 2000mm, the diameter of the sun exceeds the height of the DX image frame? You cannot image the full annulus. Even at 1500mm, say, the framing would be so tight it would drive you nuts since your alignment will not be as accurate as you get at night sighting Polaris.

I would practice on a near full moon (with the D90) to make sure you fully understand that not only the framing is tight, but that the photographic focal length of your setup may be longer than the specified lens focal length.

For example, my 3.5" Questar is nominally specified as 1250mm but I think the shortest focal length I can achieve for imaging is more like 1400mm. I don't think I can image the full moon through the Q on DX. I can only get a waxing or waning crescent in the FOV, and only by running the crescent aloing the long axis of the frame.

Edit: I found a test run using my D2h; at probably around 1400mm the moon was a very tight fit and based on computations spanned about 5/6th of the vertical frame. The moon that night was about 30' diameter, or about 3% less than the diameter of the sun on May 20.

I'm sure you understand that the full moon has virtually the same nominal diameter as the sun. On the upcoming full moon (widely "advertised" as a "super moon") it will be near perigee and therefore about 10% larger than normal. That will make for a good conservative test of the expected FOV.

In the case of my total solar eclipse, I practiced alignment for months before the Big Day, using the sun during the day.

On eclipse day, we were totally clouded out until A Miracle Occurred about 4 minutes before totality. That was fine and dandy except that my primary alignment procedure relied on sighting and tracking the sun for awhile and tweaking based on dec drift. Instead I had only a compass and altitude scale to set the polar axis, and no way to verify it before the main event. Ah... the plans of mice and men

That's why, if I were doing this, I would shoot 500mm or less. I could train a monkey to do that, which, as I said before, is a good strategy

For the exposure you just need to set a manual exposure and chimp your way in, reducing shutter speed until you get good rsults. For my total eclipse I had to do that with a 36 frame roll of film during totality . It's easier now!

For terrestrial practice, in bright sunlight, figure sunny 16, so at ISO 200 your exposure should be about 1/200s. Although your scope has an f/ratio of f/10 (I presume) your t/ratio is more important. The T ratio reflects the obstructed optics, which lose about a half stop from the nominal f/ratio. So I'm figuring sunny 16 gets you fairly close with an f/10 scope.

For the sun I would start around ISO 200 and 1/60s to 1/100s and see where you are. The sun can't be too bright or the filter would not be safe. On the other hand it can't be too dim or you would send it back as defective and unusable . But they do vary by a few stops.

If you google "solar eclipse images" you will find a list of images and from there you may find images with exposure data, and maybe, if you are lucky, using your filter. I checked my image files but don't see anything with a DSLR and my solar filters. I used a Coolpix 990 for most of my Questar solar imaging and haven't done any in years since the recent solar minimum made it pointless, short of a solar eclipse.


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Neil


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nrothschild Silver Member Neil is an expert in several areas, including camera support Nikonian since 25th Jul 2004Fri 04-May-12 11:18 PM
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#11. "RE: D90 on telescope DU-UH..."
In response to Reply # 9
Fri 04-May-12 11:23 PM by nrothschild

US
          

One final thought... assuming you live in Oklahoma, per your profile, and you are driving "a few hundred miles" west/southwest to see it, you will be lucky to catch annularity just moments before sunset. There's good news and bad news...

The bad news is that the chances of seeing the sun actually set or nearly set, on any given day in any given place in the USA, is not very good. The details depend on where you are going of course.

The good news is that, should A Miracle Occur and you get that clear horizon and clear skies, you have the chance to make a landscape shot that will be unforgettable. If one were to have a choice of anywhere in the world to go, it would be about where you will be, but it is a high risk-high reward situation.

And on the bright side, the best that can happen is a thin cloud layer. But not too much of a good thing.

Now, if it were me, I would bring the scope just to watch it visually. But for my photograph I would figure out exactly where the sun will set and plant myself someplace that has a reasonably spectacular view and shoot it probably somewhere between 100 and 200mm on DX, depending on the scene. At least enough focal length to clearly see the annulus in the image, and as long as the composition dictates. And that view might just be an attractive tree in sillouette.

When you search the internet for other images after the event, there will be hundreds of annular ring (scope) photos posted, and every one will hopefully look more or less alike, although some will be rather fuzzy, as these things always go .

But the truly spectacular images will be the landscapes. Here is a Google of annular images.

The images with neat solar prominences were taken with $2000 H-Alpha filters; you probably didn't buy one of those .

Then there are all the white light filtered scope images, which all look alike except how the ring is oriented.

Then there are a very relatively few landscapes. Some with just a nice cloud layer (they usually had to shoot higher in the sky and could not compose a nice scene). The most spectacular are the setting sun landscapes.

Like any setting sun, at some point as it approaches the horizon it is "safe" to shoot, with proper care. Same with the annular eclipse, keeping in mind that if you have unusually clear skies and/or the sun is a bit higher than I think it will be, it may be "too hot" to safely view directly yet still be very comfortable to view. The same danger that would occur at high noon, except even more insidious.

If I lived in California I might consider driving east to plant myself just where you will be, assuming I thought the risk/reward ratio was worthwhile and how lucky I felt. You are more or less forced, by geographical circumstances, to do the sunset plan so you should take advantage of it!

Oh, and don't forget the Transit of Venus on June 5th. Far rarer than the eclipse; the rain date is in the year 2117 . This will be good practice and for that the scope will be a more viable option although I think most of us will see it in progress at sunset so the same interesting landscape ops apply (you can do both!), although the focal length needs to be rather long (probably 200-300mm on DX to see Venus's shadow)



_________________________________
Neil


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patrick_g Registered since 04th May 2012Sat 05-May-12 12:00 AM
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#12. "RE: D90 on telescope DU-UH..."
In response to Reply # 11


US
          

Yup to all your commentary.

With D90 in "M" I widely (wildly?) bracketed landscape and got an image. Later I saw a sharp shadow (it was a partly overcast partly cloudy day with scattered T'storms)and with sharp shadow you can see the sun just fine so out onto the patio with scope on tripod and D90 on scope. Using the field corrector/flatener focal length changer thingy which makes scope F6.3 instead of f11 and with solar filter in place (99.999% rejection) I bracketed it and got my first solar shots ever. Not too many sun spots but a few. Tomorrow I will try again (weather permitting) without the accessory focal length/field corrector thingy and fill the frame more (f11 2000mm)I will attach a simple rod thingy that when turned into the sun casts no off centered shadow component. I have a single axis 120VAC 60Hz drive on the mount so should track the sun pretty well. I have oodles of batteries and solar panels which will make up to 14 amps built into the camper so running an inverter to drive the scope is no problem. (Scope is Celestron Pacific 8 inch SCT, quite old from when Celestron was a new company, so not computerized.)

The high plains offers a decent chance of good vis. That part of the Llano Estacado is over 4000 feet, way higher than Roswell. Our camper is 1 ton 4x4 dually Dodge with a slightly enhanced Cumins diesel. We will keep our actual site location options open for correction plus or minus weather. We can get off the beaten track safely. To quite noticibly improve the location of the sun during the eclipse would require SIGNIFICANT western travel and the track goes places we can't very well due to lack of roads unless we were to go a long long way west (risking clouds) so we will gamble on the high plains.

Not a lot of big nice trees, Mesquite and the odd cactus. Lots of oil wells and tanks. Maybe a shot with a walking beam in it. Who knows. Going to do Carlsbad caverns too as separate issue.

Thanks to every one who offered info. I think with a little practice I will do fine. I hope to have other cameras (hand held) with filters and maybe a HD video camcorder. (Two couples, all photographers so many cameras in action, hopefully, weather permitting.)

Patrick

  

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nrothschild Silver Member Neil is an expert in several areas, including camera support Nikonian since 25th Jul 2004Sat 05-May-12 12:25 AM
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#13. "RE: D90 on telescope DU-UH..."
In response to Reply # 12


US
          

Sounds like you are all geared up

I'm surprised that the focal reducer, which takes you to about 1260mm, didn't fill the frame sufficiently . (should be a fairly tight fit)

You are probably aware of this site but spaceweather.com always runs a current sunspot map for comparison. Looks like only one decent group now.

Real men use circles, not those new fangled computers (says someone with a couple of Questars designed in 1950 and not changed much since ).

Those original Celstrons are supposed to be pretty good. I almost owned one, but flipped a coin and bought a B&L 8". I didn't know anything back then .






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Neil


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patrick_g Registered since 04th May 2012Sat 05-May-12 01:38 PM
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#14. "RE: D90 on telescope DU-UH..."
In response to Reply # 13


US
          

What I don't know/understand about the digital sensor smaller (sensor cropping) so 1.5 times lens focal length is apparent focal length Field flatulence/focal reducer might fill volumes. With the reducer I got a large enough solar disk so I'm satisfied. I was marginally aware of the space weather but hadn't been there (at least not in my memory) Thanks for that ref. Looks like I may need to try some eyepiece projection photography to really get a look at solar activity. The spots on space weather agree with what I saw (no suprise.)

These old Celestron orange tubes from way back when are pretty rugged and do work. Drive is primitive. Two clock motors in opposition, one more powerful than the other. Keeps out any slop/backlash but non adjustable as to tracking rate. Needs a little manual assistance but way better than no tracking at all. I have a companion orange box power inverter (12 VDC to 120 VAC variable frequency by twisting a knob.) By fine tuning with the freq knob you can adjust drive to track at King rate or whatever. OK for eyeball astronomy and relatively short exposure astrophotography but no long exposures without star trails. I often attach the camera to a mount on the telescope and use the camera's lens to take pix with the telescope acting as a tripod for the camera and a tracking mechanism for the camera.

Anyone in the western US, Japan, China, or anywhere else along the track of the May 20 eclipse interested in eclipse glasses for a dollar a pair in small quantities? Goto www.rainbowsymphony.com. You send them a SASE and a dollar and they send you a pair of solar glasses. Larger quantities are 25 glasses at $0.85 each, cheaper yet in higher volume. I have mine and they are just fine

Thanks again for the space weather reminder and for your and the others interest and assistance. OK everyone, think clear skies!

Patrick

  

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larrysbw Registered since 10th Jan 2010Sat 05-May-12 07:35 PM
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#15. "RE: D90 on telescope DU-UH..."
In response to Reply # 0


Cedar Park, US
          

Hey Patrick,

I too, am headed out for the annular eclipse on May 20, provided the weather holds out. Plan on setup up at Billy the Kid Spring, Chaves County, New Mexico. It's on the raw edge of the Llano Estacado with a great view toward the WNW. Plus it's on the center of the eclipse path. About 60 miles west of Lubbock, the eclipse will get maximum darkening then brightening to pre-blue hour. I'm very excited about the opportunity.

I've been using my D90 with a Meade LX90 8" SCT for a couple of years now and it works GREAT! You'll need an adapter to couple the D90 with the back of the telescope. If you are using an 8" SCT or larger, you probably have a 2" port. Stay with the larger port if possible and attach the D90 directly. Also, you must use the camera in full manual mode. Now is a great time to learn the exposure settings on the moon. Try ISO640 and 1 to 15 seconds. Higher ISO's begin loosing resolution. Slower exposure times will generate unacceptable star trails unless your telescope is on a polar mount and properly aligned. This time of the month is a great time to use the moon to develop your exposure techniques.

Use zoomed Live mode and the camera's screen to focus. I use an external hand held video monitor as a focusing aid. Better visual resolution than the camera's screen.

Lots of tricks are needed and you still have a short window to get your techniques in place.

On another note, using the telescope as the prime lens will give you a field of view (FOV) of about 0.5 degrees and this will take up nearly all the available exposure screen.

I've used the telescope as the prime to catch some interesting shots of M42 in Orion with exposure times in excess of 60 seconds using the equatorial mount but getting a little late in the year to do much with M42.

The annular eclipse in western New Mexico looks like it will present a very slim window to photograph the Pleaides adjacent the moon/sun at maximum darkening. There's about a 1 minute and 34 second window of opportunity (+,-) to capture a very unique event as well as M34-M37 higher in the western sky. All work must be closely coordinated and bad weather conditions could blow it all away, but what the heck. The opportunity won't happen again in my lifetime.

If you want to discuss the eclipse opportunities in greater detail, please feel free to contact me directly at dlarrymartin@gmail.com

Enjoy,

Larry

  

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larrysbw Registered since 10th Jan 2010Sat 05-May-12 07:44 PM
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#16. "RE: D90 on telescope DU-UH..."
In response to Reply # 0


Cedar Park, US
          

Patrick,

A quick addendum to my last post. You'll need a remote switch such as an MC-DC2 from Nikon to remotely trigger the shutter. I'd recommend purchasing a knock off from eBay for about $4.00. I use both the timer version and the manual single-click versions. Make sure you get the manual switch with the connector for the D90. I usually purchase several at at time since the cost is low. Also have the metalized connector on the camera end. Delivery is quick and reputable. Here's the eBay link I use:

http://www.ebay.com/itm/Remote-Control-Shutter-Release-Nikon-D90-MC-DC2-MCDC2-D5100-D5000-NEW-CABLE-/150809151311?pt=Camera_Camcorder_Remotes&hash=item231ced074f

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patrick_g Registered since 04th May 2012Sat 05-May-12 11:18 PM
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#17. "RE: D90 on telescope DU-UH..."
In response to Reply # 16


US
          

Great post. Thanks for info. Unfortunately I can't seem to break the code for BUY NOW. Delivery will be too late but I wan't to order anyway.

I bought a CNC 2 inch adapter to skip the T ring setup and mount the camera to the telescope back with or without field flatener/focal reducer. It attaches nicely to D90 and has a grove that accepts a knurled screw for ultimate security. I am using a UV filter as a dust blocker for when unmounted from telescope.

I will experiment with bracketing and multiple exposure settings. Haven't used on this camera yet. Hope I can do it in "M" mode.

Patrick

  

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