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aostling
03-01-2009, 05:33 PM
Orion sells a complete 90mm Maksutov telescope for $250, compared to about $4000 for a Questar of identical aperture and focal length. I added a red-dot finder and upgraded to a 35mm Orion Ultrascopic eyepiece which gives a magnification of 36X. I know Questars are supposed to be fantastic, but this Orion is very well-made too.

Last night I gazed at Saturn through it, seeing the edge-on rings as a fine line bisecting the planet orb. But I got the telescope mainly for "digiscoping" photos of birds and wildlife. It's easy enough to turn an adapter on your lathe, to couple a P&S camera (like this Panasonic LX3) to the eyepiece.

According to the online digiscoping calculator http://www.jayandwanda.com/digiscope/digiscope_calc.html this combination of camera and telescope is equivalent to a 2143mm f5 lens on a 35mm camera. Here you can see the view of an American Avocet I took this morning -- the bird is taking a caliper reading of its wing, maybe.

The adapter has a stepped ID and a stepped OD, and fits inside the accessory tube of the camera, and over the eyepiece of the telescope. It is acetyl (Delrin) which thermally expands much faster than the aluminum parts to which it is mated. Hot days will soon be back in Phoenix, but I'm wondering if this particular set-up might be relatively insensitive to thermal expansion, since part of the adapter is constrained from growing by being inside the accessory tube. I'm keeping my fingers crossed.

http://i168.photobucket.com/albums/u183/aostling/digiscopingsetup.jpg

http://i168.photobucket.com/albums/u183/aostling/AmericanAvocet.jpg

ammcoman2
03-01-2009, 06:31 PM
Very nice setup - and the photo of the "boyd" ain't half bad. I'm amazed that you can get that much detail, contrast and clarity at such a focal length. I figure however, that the camera has something to do with it. I have a G9, so am a bit biased!

Geoff

P.S. would love to see some more details on the adaptor tubes you made up.

Your Old Dog
03-01-2009, 06:31 PM
Nice looking setup and great picture. Keep posting as I have a serious interest in owning a scope that will allow me to gaze at the heavens. Would like to drag one out to the mid-west with me in an RV and spend the night looking at the heavens. I think I'll find my true place in the world when I get a better look at the universe!

The Benro sticks look a lot like my Gitzo 1325. Is that a RRS BH25 sitting on it? I have the RRS BH55 and love it.

aostling
03-01-2009, 07:54 PM
I have a G9, so am a bit biased!

Geoff

P.S. would love to see some more details on the adaptor tubes you made up.

I have a G9 too, and I'm hard-pressed to choose between it and the LX3. But the G9 cannot be used for digiscoping with most eyepieces; when it zooms to telephoto the entrance pupil of the G9 lens rapidly retreats backwards (into the camera). Hardly any eyepieces have sufficient eye relief to prevent the vignetting which this causes.

The LX3 is not ideal for digiscoping, either. The 35mm Ultrascopic eyepiece has 25mm of eye relief, and that is sufficient when using the LX3 lens at max telephoto (which is a paltry 60mm).

Here's the adapter, sandwiched between the accessory tube (which screws into the LX3 body) and the eyepiece. The diameters are machined for a sliding fit which will not jiggle the telescope too much. A shoulder on the ID is located so that the accessory tube overlaps the eyepiece by 0.15". That was determined by trial and error (before machining) as correct for ensuring that no vignetting occurs when the lens is set to max zoom of 60mm.


http://i168.photobucket.com/albums/u183/aostling/adapter.jpg

rockrat
03-01-2009, 07:55 PM
Nice setup. I have an Mead ETX and a Cannon S60 with the Cannon lens adapter. I have been trying to find time to put them all together. I will have to make a connection between the two but it will be a bit different than yours. You have re-inspired me.

Looks as though you have good aperture now. How far off from the bird were you at the time?

And your in Phoenix? Hmmm.... I guess we will be seeing some astrophotos soon as well.

Oh, when did we quit using "eyepiece projection" and go to digiscoping? Have I have been out of the amature astronomy stuff that long?

rock~

aostling
03-01-2009, 08:03 PM
The Benro sticks look a lot like my Gitzo 1325. Is that a RRS BH25 sitting on it? I have the RRS BH55 and love it.

Funny you should mention this. When I was taking the photo this morning, there were several other birders walking around with their carbon fiber tripods. One guy had a Gitzo which appeared to be an absolute duplicate of my Benro C158-n6. I've also noticed the same tripod as being sold under the Induro label. But the Benro costs much less. I suspect these are all made in the same Chinese factory. It's an absolutely fabulous tripod.

Ditto for the head, it is a Benro KS-0. I have not had a Really Right Stuff head, but I don't see how it could be much better.

aostling
03-01-2009, 08:57 PM
Oh, when did we quit using "eyepiece projection" and go to digiscoping? Have I have been out of the amateur astronomy stuff that long?
rock~

I don't police these terms, but according to this http://www.televue.com/engine/page.asp?ID=243 digiscoping differs from eyepiece projection in that the camera lens is not removed.

The photo of the avocet was from a distance of about thirty feet.

Evan
03-01-2009, 09:22 PM
Leaving the lens on and placing it as close as practical to the eyepiece is called afocal coupling. It works well with many cameras and can be used with nearly any device that has an eyepiece. It's how I take photomicrographs.

I don't use it for astrophotography because of the difficulty focusing as well as light loss. When I use my Canon on my telescope it is prime focus photography, no lens or eyepiece. The image from the mirror is directly focused on the sensor for maximum light gain. I have an eyepiece tube adapter that I made that has a body cap on the end so the camera is just attached to the body cap.

ammcoman2
03-02-2009, 09:02 AM
Allen,

Thanks very much for posting the adaptor photo. Here I was thinking threading etc and you kept it to the "kiss" principle.

Geoff

rockrat
03-02-2009, 11:24 AM
30 feet, nice. I would take it that the birds are not too excited when you are around or are you in a blind?


I don't police these terms,

I guess this just means that I'm getting older. I'm starting to sound like all the other old guys that I hang out with. I also remember something about thongs were once worn on the feet. A quick Google image search has shown me that a) they dont look the same and that b) they are not worn on the feet anymore. Strange, but I dont feel as bitter about the changing of this definition.

rock~