I took a quick peek outside to see if the skies were clear. They looked better than last night. The sun would not be rising until about 6:30AM and sky glow would happen about an hour before sunrise. I decided to rush out to HJRO and look at a few objects, perhaps test some eyepieces and maybe photograph the comet.
I wanted to test the new Tele Vue 55mm Plossl that a club member found for me on the internet. He purchased it for me from an Astromart ad and I was able to pay him and get the eyepiece yesterday. It's a 2 inch eyepiece and requires a telescope with a large focuser.
I drove to Tim Horton's and got a hot chocolate before heading to the observatory, just to have something to insure I would stay warm for the next hour or so of observing.
Comparing of the eyepieces seemed to be the best thing at first, because of clouds obscuring the horizon and the sky looking like a soup bowl, with clouds and thicker haze near the horizon and some clearing above.
The Losmandy mount was directed to look at Saturn and I quickly opened the shutter and rotated the dome toward Saturn. There is was. These eyepieces are low power eyepieces that I was comparing. A 40mm wide 68 field of view Williams Optics Swan, a Tele Vue 55mm Plossl, and "the Harold Wonder" eyepiece. (We wonder what he made it from.) The Harold Wonder eyepiece is a great eyepiece for public out-reach and Big Bertha. How would it hold up against the others. I'm going to give a better review later in the blog and possibly in a short piece for our Star Stuff FAAC magazine. I write an HJRO update column that I try to get into each month's newsletter. FAAC has a newsletter and I was the editor of it for about a year and started creating HJRO updates during that time. I still write up some kind of update for each month's newsletter and submit it to the club, in case they want to put it into the newsletter.
The quick summary is as follows:
Viewed Saturn - Conditions poor with haze, but at low powers it still looked good through the C14 at 3911mm F11. All three eyepieces showed a good deal of detail and I could see a few of Saturns moons, or at least stars that looked like it's moons, I didn't have time to check and verify this.
The three eyepiece performed essentially the same way. I was actually surprised how well the Harold Home built eyepiece held it's own against the other two eyepieces. It looks like the Harold Homebuilt eyepiece is a 55mm eyepiece, with essentially the same field of view and performance that the Tele Vue 55mm plossl has.
I also looked at Comet Panstarrs but it was in more clouds and haze than Saturn and the view was disappointing with all three eyepieces. The tail could not be seen and it looked like a fuzzy star.
Looking at M13 before the sky grew to bright the three eyepieces also showed very similar views. The Televue Plossl had a more flat and smaller apparent field of view than the Swan. The Televue had a very flat and detailed look. The quality of it was apparent and it did slightly outclass the other two eyepieces. It had a flatness and sharpness that is hard to quantify, it was almost a subliminal difference. It was apparent but very subtle and something man viewers may not even see as a difference. I was shocked at how well the Harold home-built eyepiece performed. It offered sharp stars out to the edge of the field. Perhaps a little bit of softness and pop was lost compared to the Tele Vue. There was something that was probably an advantage for the Homebuilt eyepiece over the others and that was the wider glass in the eyepiece and an apparently huge exit cone. This might cut down on the light a bit for some viewers, but with a large 14 inch it wasn't apparently any darker than the other eyepieces, even if larger exit pupil cone of light may cause loss of light from the primary mirror (this being a theory by some.)
The large light cone of the Harold home built gave a slight problem at some distances from the eyepiece. There was a shallow area of a certain distance which caused a dark spot from the secondary to appear, really a pair of them. Kind of like a mirror testing pattern. That might be a distraction to some viewers at some distances. They might see the dark pattern and wonder what that spot is? I've heard this from some viewers before. This is easily overcome by movement of the eye in relation to the eyepiece. Some simple eyepieces with less glass components may show this more than a more complex design with more glass in the path of the eyepiece. I've seen this in a "single lens" eyepiece I made as a kid as a "cheater finder" which was a 60mm single lens eyepiece. At low powers one will at times find the secondary obstruction shadow to appear, and this can happen with the Harold Wonder eyepiece. At least with the C14.
The Harold Wonder eyepiece gives a slightly more forgiving area where you can look and see the entire image. It's much greater when looking at the moon. You can see the image from anywhere within a 2 inch circle behind the eyepiece, with plenty of room to have an off axis view that is great on Big Bertha and the moon with the Harold Wonder eyepiece. The Tele Vue has a wider more forgivable exit cone than the Williams Optics eyepiece. It's big and for this eyepiece for Saturn on the C14 it's almost as large as the Harold Wonder provides. The William's optics needs your eye to be centered to get the view right, but this is common with "wide field" eyepieces that offer a wide view internally with a big piece of glass inside the eyepiece for the "image to be projected on".
They were all winners in their own ways. None had the clear advantage. I'd give the flat field and sharpness of star definition to the Tele Vue. The ease of use for sidewalk astronomy and light weight advantage has to go to the Harold Wonder. The wide field immersive view would go to the 68 degree field of view 40mm Williams Optics Swan. All have an advantage in some aspect and none are a clear winner. Of course for rarity and novelty, the Harold "home built"has to have some extra points if you want to show someone something that is truly unique.
This test was limited to the C14 at F11. I didn't test them on other wider field telescopes. I'd like to test them all on Big Bertha for example which is a F5.35 Schmidt Newtonian which the Harold Wonder eyepiece came with.
I only had time to look at three objects before the sky started to get bright. I tried to take a photo of Comet Panstarrs, and may post it later. That photograph turned out poorly due to haze and cloud cover in front of the comet. I was actually surprised that I could see or photograph the comet at all.
Below is a snapshot from the observatory this morning I took outside. I processed this a bit using contrast and brightness and created a few different exposed looks of the sky and observatory and then took those into Photomatix HDR processing and created an HDR that gives you a look at the observatory and a good idea how the clouds were. The comet was in the low cloud bands you can see in the photo.
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