I got a nice white-light view of the sun in Mat's Dob this morning (thanks Mat, sorry I missed lunch!), so this afternoon I set-up in my own backyard. I finally got the binoviewer to focus with the Coronado PST! I used the thread-on 2X relay Barlow that came with it, and stacked that on top of a 2.8X Barlow. The scope would just reach focus. As I suspected, the magnification was too high, so I also used 0.5X focal reducers on each of the 40mm Plossls I used. The final magnification was still on the high side for the seeing this afternoon, which was really soft due to thermal currents rising from the ground as well as the breeze. I'll post a link to a photo of my setup later, once I upload the pic to Photobucket. The biggest problem with a binoviewer setup like this in daylight is the tiny pupil opening of the human iris. Combine that with a tiny exit pupil from the binoviewer, ridiculously long eye relief due to the Barlows and long FL eyepieces, and getting your head in just the right position is a huge PITA. The seeing was too poor for any acuity gains from stereo vision to be realized. Also at higher powers, prominence visibility decreases. Another problem with this kluge setup is just too much glass in the optical train, for such a small objective. I'm sure I lost a sizable fraction of my throughput to absorption. It would be nice to have about a 6-inch aperture H-a scope. So I'll probably not use the binoviewer setup on the sun in H-a very much unless the seeing is superb. Today the best views with the PST were with 9mm and 7mm ortho eyepieces used alone. There is a pretty good-sized, though not bright, prominence on the western limb, and a smaller but brighter one on the eastern limb, with a huge sunspot complex right near the limb. Many smaller prominences scattered around the limb, and several flocculi seen on the solar disk. I watched for about 90 minutes but saw not a hint of a flare. I also set up my C5 with a glass TO filter, but was surprised to see it badly out-of-collimation so only low powers could be used. I had collimated it about a year ago and hadn't used it since so I'm wondering what happened. Combined with the poor seeing, I quickly put the little Celestron back in the box with a note to re-collimate it. Should have tried the C6 instead. It still has that "new telescope smell". I also had a problem getting good balance with the C5 and binoviewer combination on the little GEM that I was using today. There's a pair of wild mallards that have decided to drop-in every day, and are pretty tame birds. I feed them stale bread and they walk right up to me now that they know I'm harmless. The down side is that I have to hose-off the patio before setting up the scope. They hung-out a few feet away all afternoon while I observed, no doubt waiting for the next handout. They'll disappear soon when the female decides it's time to raise a family back at Decker Lake.
Here's the pic of the PST/binoviewer setup, on my small GEM: http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/PSTampbinoviewer0... It was pretty neat seeing the sun in H-a with both eyes, a first for me. On Sat, Mar 30, 2013 at 4:45 PM, Chuck Hards <chuck.hards@gmail.com> wrote:
I finally got the binoviewer to focus with the Coronado PST!
No, no, no. Too easy. One eye and a bottle of Jack. Pretend you’re young. The Jack’s for the pretending. Oh, and Easter. On Mar 30, 2013, at 9:41 PM, Chuck Hards <chuck.hards@gmail.com> wrote:
Here's the pic of the PST/binoviewer setup, on my small GEM:
http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/PSTampbinoviewer0...
It was pretty neat seeing the sun in H-a with both eyes, a first for me.
On Sat, Mar 30, 2013 at 4:45 PM, Chuck Hards <chuck.hards@gmail.com> wrote:
I finally got the binoviewer to focus with the Coronado PST!
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I wish it was easy, Dave. Took me two days to figure it out, and even then it took practice. See my explanation to Patrick. But the bottle of Jack is still good advice. On Sat, Mar 30, 2013 at 9:59 PM, Dave Gary <davegary@me.com> wrote:
No, no, no. Too easy. One eye and a bottle of Jack. Pretend you’re young. The Jack’s for the pretending. Oh, and Easter.
Interesting that the eyepiece and binoviewer are as big as the OTA. :) I hope you can bring the setup to a SPOC star party this year. Arrive early during the unofficial social hour and we can all have a look. 'Course now you have me wondering if we can hook the club's binoviewer to the Daystar when hooked to the Bogdan... patrick On 30 Mar 2013, at 21:41, Chuck Hards wrote:
Here's the pic of the PST/binoviewer setup, on my small GEM:
http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/PSTampbinoviewer0...
It was pretty neat seeing the sun in H-a with both eyes, a first for me.
This is not a good setup for group viewing. Your iris is almost fully closed in daylight. I found using the binoviewer in daylight was very difficult to get my eyes positioned just right. Combined with the small exit pupil produced by high power with a small aperture, and I think that any but experienced observers would not be able to see with both eyes at the same time. On the 8" refractor, it would be much better since the telescope would produce a larger exit pupil. But remember that every single user would have to adjust not only the interpupilary distance, but the individual diopter adjustments as well. Binoviewers are much easier to use if your irises are open fully. In daylight, it's a pain. Seeing the sun isn psuedostereo is cool, but there's a trick to it. On Sat, Mar 30, 2013 at 10:05 PM, Patrick Wiggins <paw@wirelessbeehive.com>wrote:
Interesting that the eyepiece and binoviewer are as big as the OTA. :)
I hope you can bring the setup to a SPOC star party this year. Arrive early during the unofficial social hour and we can all have a look.
'Course now you have me wondering if we can hook the club's binoviewer to the Daystar when hooked to the Bogdan...
patrick
On 30 Mar 2013, at 21:41, Chuck Hards wrote:
Here's the pic of the PST/binoviewer setup, on my small GEM:
http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/PSTampbinoviewer0...
It was pretty neat seeing the sun in H-a with both eyes, a first for me.
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I've always found a big sun shield to be essential for pleasurable sun viewing.
Here's the pic of the PST/binoviewer setup, on my small GEM:
http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/PSTampbinoviewer0...
It was pretty neat seeing the sun in H-a with both eyes, a first for me.
On Sat, Mar 30, 2013 at 4:45 PM, Chuck Hards <chuck.hards@gmail.com> wrote:
I finally got the binoviewer to focus with the Coronado PST!
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Erik, the problem with the binoviewer in daylight isn't one of comfort. Yesterday was on the cool side and quite pleasureable. I wear a brimmed had when observing the sun, and have been known to set up in the shadow of a building when the geometry works out. The difficulty with a binoviewer in daylight is that the pupils of your eyes are as small as they ever get. Combine that with long eye relief of a low-power eyepiece and a small exit pupil from high power (thanks to the relay Barlows) and a small objective aperture, and you have two very small "sweet spots" that you have to align perfectly in order to use the binoviewer. The net result is a pair of very small virtual images floating far from the eyepieces, that have to align perfectly with a pair of small eyeball openings. Inter-occular spacing must be dead-on, and your head placement must be dead-on. A shift of only a millimeter or two means you lose one or both sides of the image. Can you hold your head still within a millimeter for 10 to 30 seconds? I find it VERY difficult if not impossible, outdoors perched on a chair. A sun shade won't affect this problem much, if any. Your pupils will still be very small and most folks don't have the body control of a Hindu yoga master. Using large aperture will help. That will increase the size of the final exit pupil, so even if the observer's pupils are completey contracted, there is more "wiggle room" for head positioning. That's why at SPOC, I'd rather use a binoviewer on the Andy scope for public viewing, than on a PST or double-stack. And a double-stack image is inherently dimmer than the PST in the first place. In a binoviewer it would be even dimmer. Unless your solar imaging system provides a large exit pupil, binoviewers are much easier to use at night, when your entrance pupil is open 5 to 7mm. Head placement is not as critical, by a long shot. On Sun, Mar 31, 2013 at 9:01 AM, <erikhansen@thebluezone.net> wrote:
I've always found a big sun shield to be essential for pleasurable sun viewing.
Here's the pic of the PST/binoviewer setup, on my small GEM:
http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/PSTampbinoviewer0...
It was pretty neat seeing the sun in H-a with both eyes, a first for me.
I was not referring to air temp but rather being shielded from the suns glare, although a big umbrella with a hole in it was nice on hot days. With a brimmed hat I was always bumping the eyepiece. Of course, the drawback is you need a sturdy mount.
Erik, the problem with the binoviewer in daylight isn't one of comfort.
Yesterday was on the cool side and quite pleasureable. I wear a brimmed had when observing the sun, and have been known to set up in the shadow of a building when the geometry works out.
The difficulty with a binoviewer in daylight is that the pupils of your eyes are as small as they ever get. Combine that with long eye relief of a low-power eyepiece and a small exit pupil from high power (thanks to the relay Barlows) and a small objective aperture, and you have two very small "sweet spots" that you have to align perfectly in order to use the binoviewer.
The net result is a pair of very small virtual images floating far from the eyepieces, that have to align perfectly with a pair of small eyeball openings. Inter-occular spacing must be dead-on, and your head placement must be dead-on. A shift of only a millimeter or two means you lose one or both sides of the image.
Can you hold your head still within a millimeter for 10 to 30 seconds? I find it VERY difficult if not impossible, outdoors perched on a chair.
A sun shade won't affect this problem much, if any. Your pupils will still be very small and most folks don't have the body control of a Hindu yoga master.
Using large aperture will help. That will increase the size of the final exit pupil, so even if the observer's pupils are completey contracted, there is more "wiggle room" for head positioning. That's why at SPOC, I'd rather use a binoviewer on the Andy scope for public viewing, than on a PST or double-stack. And a double-stack image is inherently dimmer than the PST in the first place. In a binoviewer it would be even dimmer.
Unless your solar imaging system provides a large exit pupil, binoviewers are much easier to use at night, when your entrance pupil is open 5 to 7mm. Head placement is not as critical, by a long shot.
On Sun, Mar 31, 2013 at 9:01 AM, <erikhansen@thebluezone.net> wrote:
I've always found a big sun shield to be essential for pleasurable sun viewing.
Here's the pic of the PST/binoviewer setup, on my small GEM:
http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/PSTampbinoviewer0...
It was pretty neat seeing the sun in H-a with both eyes, a first for
me.
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participants (4)
-
Chuck Hards -
Dave Gary -
erikhansen＠thebluezone.net -
Patrick Wiggins