Monday, November 29, 2021

a new tool

Went to Pinnacles last night where I met up with Jamie and Peter.  Moonrise was around 1am but with darkness by 6:30pm it was still a full night.  I brought the 8-inch bent refractor, this time outfitted with my NV device and its necessary filters in a filter wheel.  Some incredible sights to be seen!

It was fairly cold and not as transparent as predicted.  I only got to 21.00 on the SQML.  It got very cold pre-dawn and I woke while it was still dark.  Rather than trying to continue to sleep I packed up and was gone by twilight.  Peter was still asleep.

I started out with IC 59, a reflection nebula, and IC 63, a HII Ionized region, both near Gamma Cassiopeia.  It took some switching between filters (a really necessary item) in the wheel before finding the 7nm showing the nebulae.  IC 63 was brighter, arrowhead shaped, with two bright streams in its body, with filaments and streamers coming off the wide end.  IC 59 was somewhat fainter and more evenly illuminated, with some mottling, and softer edges.  With the 3nm filter the sky background is darker but the nebulae have more contrast, and I could see the two nebulae are connected by wisps of nebulosity.

Next was the Pacman nebula, NGC 281, anther HII ionized region.  This really looked like an angler fish gobbling the star in its mouth, as a bright loop of nebulosity formed the lower lip and jaw giving a 3-D effect.  There was a prominent dark nebula running E-W, and crenulations along the eastern boarder of the nebula.  Streamers of nebulosity lifted up the north back of the nebula, like evaporating dry ice.

Sh2-176 emission nebula was next.  This one was a no-show in my 10-inch a few weeks ago, and again was very tough.  I was not using enough magnification so I had not enough image scale.  I had Reiner Vogel's Sharpless Observing Guide with me, and spent a good deal of time in the correct star field.  Vogel says this is "a planetary nebula at a distance of about 140 pc. The central star is a blue subdwarf."  After a long while I did have steady views of a thin strip of excessively faint nebulosity forming southern arc of the broken circular nebulosity.   Not bad considering Vogel had a negative observation with his 22-inch.

I moved to Auriga next, to IC 405 and all the surrounding nebula.  This area was heavily clouded with nebula, and is really too much to describe.  IC 405 showed all of its huge comma-shaped form, and tipping the scope a little I could easily see IC 410, IC 417, Sh2-230.  These are all connected with a fainter body of nebula; these appear as brighter knots in the larger structure.  Sh2-230 showed crenellations along its eastern edge.  Tipping the scope a little to the northwest and I saw the relatively bright puffs of Sh2-228 (near a bright star) and Sh2-226.  


I moved on next to the Heart and Soul Nebula.  I had seen bits of these through my 10-inch and other scopes, but nothing prepared me for the spectacle of these through NV.  I used the 4-inch scope as my finder, using no filters, and when I reached the target area proceeded to flip through the filter wheel.  I went through the light pollution reduction filter, and could see faint nebulosity; 610 longpass nearly the same.  3nm Halpha and the sky both darkened and the nebula burst into view, two huge loops meeting in Mel 15 open cluster in the middle; the very bright concentration of NGC 896, and the large diffuse glow of iC1848 on the edge of the field. I called over Jamie and Peter to share the view. 

We proceeded to look at other showpiece objects.  The California Nebula, in-your-face bright, long, with folds and streaks running through it.  The Horsehead and the Flame in the same wide field, where we could see the snout, and I was amazed at how large IC 434 was.  M42, which looked like an opera set in flames, with an amazing 3-D quality to the view.  






After that I went back to challenge objects, starting with Simeis 147.  The large edge of the irregularly round nebula was still fairly easy to pick out, and seemed thicker than what I recall from seeing it in other scopes.  The difference was with NV I could see the smoky, highly mottled cloudiness inside the round shape, which I think is impossible to see without a wide field and NV.  The wisps were not as sharply defined as in the photo, but definitely there.

Sh2-242 was nearby, Vogel says it is and HII region is excited by a B0V star and appears to lie at a distance of 2700 parsecs.  In his 22-inch he observed it "at 100x with either UHC or H beta, an extremely faint glow was suspected. With UHC, glow was suspected mainly E of star, with H beta displaced to SW relative to star. Doubtful observation."  For me it was obvious, a bright round patch with a dark cut-off on the NE rim, just beyond the star.  This shows clearly in the photo.

Next was supernova remnant Sh2-224, SNR G166.1 +4.4. 4500 pc distant and 72.0 pc in size.  For Vogel "with OIII filter a faint filament was suspected at the N edge of the SNR. Doubtful observation."  For me it was still a difficult observation with 8-inch and 7nm, but I did see two very weak filaments, the northern which was longer and brighter, and the southern which was a difficult fleck, with a relatively bright field star near the eastern tip of the northern filament.  

Next was Sh2-216, an ancient planetary nebula.  A year ago at Pinnacles with my 10-inch I recorded:  "This night I saw its brighter eastern arc.  At 35x and with OIII, it was a very large, moderately faint arc covering about one quarter of what should be a round nebula.  That quarter filled about one quarter of my field, so it is a very large nebula indeed.  I felt some haze present in the center of the nebula within that arc.  It is the second closest PNe to earth (the Helix nebula is closest, according to the latest Gaia data), which explains its size, and is likely rather old."  Vogel with 14-inch: At 50x with OIII filter, the NE edge could be observed and showed the highest contrast to the background.  The NE edge is also distinct in my 80mm finder equipped with UHC filter, but very difficult in my 22" Dob due to the restricted field."  This night with the 4-inch the nebula was seen quite easily in its full extent when rotating the 7nm filter into place while looking through the eyepiece.  Unmistakable large roundness with a stronger eastern arc.  These features were enhanced with the 8-inch.  What is more, I saw this nebula is in front of a trunk or stream of very faint nebulosity to its east, with a row of stars running N-S defining the nebula's east edge.  I could find this nebula on a wide field from Aladin:   


I ended the NV with an attempt to use the device hand held to have a look at Bernard's Loop -- and I could see it but I could not focus clearly.  But I could see the entire "C" of Bernard's Loop along with the tremendously large Meissa Nebula.  I'll figure out how to focus it for next time.
 



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