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6/08/2011

Observing Session Tuesday, June 7th, 2011; 10 inch Dob

Since participating in the Zambuto mirror project and then cleaning, and reinstalling my mirror, I have wanted to get the 10 inch out to collimate it, and make some adjustments to it. So on Tuesday, June 7th, 2011, I took the ten inch out locally and had some fun with it. There's a spot I go locally, where I have permission, that is mostly free from stray light and allows me a decent view of the sky above 20 degrees.

The scope collimated easily, it usually does, and I had it up and cooling in a matter of minutes. I did not take my sketching materials and I only had my premium eyepiece case (my Pentax XW eyepieces, the 5mm, 7mm, 10mm and 14mm and the 27 Panoptic). I mainly for this night used the 14mm as my finder and the 10mm and 7mm as my main eyepieces in the eyepiece holder that night.

After getting settled, and setting up my observing chair, I spent some time on the moon. I used my 5mm Pentax and the images were sharp, crisp and clean. My first object was what I believed to be Maurolycus which instantly made me regret I did not bring my sketching materials (please provide some latitude in crater identification as I am still learning the moon). Inside this large crater was a perfect pacman shape shadow. My son was with me, since I am still not completely healed (I am starting to cough hard again, sigh) and he was amazed by the shape, agreeing that it looked just like a pacman. I also looked at what I believe are Aliacensis, Werner and Blanchinus. These were lovely and had a rich contrast in black, gray and white on their rims. Any would have made a find sketching object. Next time I will get them (would have done it tonight but guess what is back . . . clouds!). On Tuesday, after doing a star count in Bootes and Ursa Major again, I estimated the NELM to be at 5.7 to 5.8 and the SQM rather agreed with this coming in at a 20.39 (conversion would put that at a magnitude 5.75 NELM or so.

My next object was Saturn and I spent a good deal of time on Saturn. Saturn was beautiful, showing its storm and its four moons. The rings looked far better than last year and I actually got some contrast out of it. Saturn is one of my son's favorite objects so he took some time taking in the views, while talking about his thoughts on the new Nintendo Wi console that is coming out in the future.

After spending a good forty-five minutes on the moon, and another thirty on Saturn, I went off the moon and duplicated my galaxy observations from Sunday night in terms of the Herschel ones. Very faint and I can certainly tell the difference between the 14 and the 10 inch on these two (more moon light also).


Next, I jumped up to M51 to see if the 10 inch could get SN2011dh into view. This was a harder observation than in the 14 inch truss dob. I was able to see 3UC 275-121854 which is a magnitude 13.58 star to the SE of the core with N being straight up (bottom right of the core, the first bright star in the trail of four. Here is a link to local Salt Lake Astronomical Society member Kurt Fisher's gallery where he has posted a finder chart with these stars labeled on them). I could hold this star with direct image as seeing allowed, which was pretty often. 3UC 275-121870 is a magnitude 13.74 star and this one was slightly hard to view, taking averted vision to obtain it, and then direct vision would maintain the observation until after that. SN2011dh is reported at magnitude 13.3 right now, and should be seen. Using averted vision I was able to pick up the supernova and then to hold it. It appeared not as crisp tonight versus Sunday and often appeared fuzzy. There were a few times that I felt it was visible, and then others when I lost it all together. Based on this experience, and the fact that when I looked a waxing crescent moon was in the sky I would say that my ten inch will not be able to detect SN2011dh for the rest of this waxing cycle of this moon. It also shows that as reported at Sky&Telescope medium (for me 12" to 16" telescopes) and large scopes (17 inches plus) should be able to bring in this supernova visually. A ten inch is really pushing it though it is possible, just don't expect to hold it in your view.

After M51 and the forty-five minutes I spent there, I next took the scope over the M13 and observed a lack luster globular cluster. It was missing its brillance, and it did not just pop out for me. Part of this was location. Hercules was heading up toward zenith but still in the eastern sky and there is a lot of light pollution in that direction. The heavy light pollution of the Salt Lake Valley really impacted the view. It did remind me of how spoiled I have been to be at several dark sites and to gaze at this wonderful globular and see it in such splendor. Five years ago, M13 was a wonderful sight from the backyard and this shows why viewing at a dark site is so wonderful and an experience I highly recommend on a regular basis.

After M13 I went to Antares which had risen and I hoped over there and took a look at M4. Not much in light pollution. I then hoped over to the star Vega, and then took a look at the Double Double and ended this night with the M57, the Ring Nebula. Position in the sky, M57 is in the north-eastern sky and that lovely light pollution is heavy there, drowned out most of the stars, but without a filter I was able to detect a faint greenish color to the ring and saw its shape and its fuzzy interior. It was good to see an old friend for the first time in 2011. The summer constellations are arriving, and I fear I need 3 good nights with the spring constellations to complete the H400 (and some open clusters in Puppis next winter). Oh well, another year may go by.

So no sketches this time. It was wonderful to be out under the stars and spending some time with my son and pushing the scope to see what it could do. It reminded me of why I am glad I kept my ten inch and sold my 8 inch scope. My son and I talked about that and he wished I had kept the 8 inch scope. I have an 8 inch mirror blank so I will be making a new 8 inch reflector because that scope is such a pleasure to use on planets, double stars and on deep sky objects. However, the ten really did allow me to push into some challenging magnitudes that night, and it was fun to do that. It isn't that much heavier than the 8 inch and it sets up easily and quickly. It is my scope of choice for using in the backyard and locally because of its convenience unless I need the 14 to do something. I am hoping to get the 20" up here in July for some fun comparisons and to report on that. Overall a quick night, but a good night. Lets hope summer arrives and clear skies to all.