A couple of nights ago I had opportunity between rainy days for observing doubles with my old 1985 Celestron Super C8 Plus. Over the last 37 years I've learned what it takes to make that optical design perform optimally. Some advice on Cloudy Nights about dew prevention has also contributed to that. I'll be posting in the Cats & Basses forum what I've learned to help my Schmidt-Cassegrain telescope to provide a good views.
In my observing list from SkySafari planner for Perseus, there were these 10 pairs brighter than 8-1/2 magnitude and separations less than 10 arc-seconds. Observations of these are shared below. For some I've added supplementary information from SkySafari about the primary component. So rather than just bright dots close together in the sky I can thus appreciate the grandeur of these wonderful celestial objects.
Ocean Observatory, Coos Bay, Oregon
No clouds, good to very good seeing, good transparency, 1 day before full Moon, viewing doubles in Perseus, observing from around 7:00 to 8:30 PM PDT
Celestron-8, f/10, 2032 mm focal length
Magnifications mostly 132X to 264X, using APM Superzoom
- Observations are on-going real-time impressions at the eyepiece captured on voice recorder, transcribed into my Astronomical Observations spreadsheet.
- Σ = STF
- OΣ = STT
- PA = position angle
- C.I. = color index (B- minus V-magnitudes)
- Double star information from SkySafari
- Double star, 38 Persei, Atik, BU 535 - 3.9/6.7 magnitudes @ 1.1 arc-seconds, @ 264X seeing isn't perfect, but I've got a nice Airy disc on the primary with pieces of diffraction rings sometimes visible, I believe I can see the secondary at times, always at same PA, but being that close and with that much Delta-V is too much for a clean split under the seeing conditions
- Double star, V572 Persei - 6.7/8.2 magnitudes @ 1.7 arc-sec, @ 132X this is part of a nice little triangle of field stars, there's a bright yellowish star (giant 35X Sun's diameter, mag. 5, C.I. = 1.10) off to one side, then the double is at a wide included angle (~140°) going on to the 3rd star of 8th mag. - an attractive field, @ 264X the split is seen, nice brightness contrast and separation, there's a little bit of dark sky between 'em, a bit more magnification would help, the PA of the secondary is nearly the same as that going to the yellow-orange star, the triangle is still within the FOV with a 3rd field star forming another triangle with the double and the yellow star, a nice interesting field, V572 Persei is an eclipsing binary
- Double star - 6.5/7.2/9.2/10.0 magnitudes @ 1.9/20.8/139 arc-seconds, @ 132X this is in a very interesting field, immediately seen resolved at this low power, nice separation and brightness contrast, B and C have nearly the same PA, the distant 10th mag. D-component seems brighter to me than the 9th mag. C-component, a nearly right triangle is formed by D to A-B to C, A and B are showing traces of diffraction rings, I'm very pleased to have observe this interesting field
- For comparison this has been previously observed on 2004-Oct-24 with a 10-inch reflector:
Triple star - 7/7.5/9 mag. @ 1.9"/20.7"; @ 96X closer pair difficult, but pops into view from elongated star when seeing cooperates
- Double star - 6.7/8.5 magnitudes @ 2.9 arc-seconds, @ 132X nicely resolved, it took some time to definitely identify this pair in the FOV, large brightness contrast, plenty of dark sky between 'em, @ 264X the seeing has mushed out a bit, then it smoothed out again, this isn't too far from the zenith which helps, there is a slight color difference with secondary perhaps grey with a hint of blue, there are few field stars at this power, but nonetheless it was worth observing
- Double star - 6.8/7.7 magnitudes @ 3.6 arc-seconds, well @ 264 X this one is really easy, there's a lot of dark sky between the components, these are pretty nice star images, diffraction rings are visible part of the time attesting to the fairly decent seeing, no colors are noted, no field stars are prominent in this narrow FOV, the primary has 3-1/2X the Sun's diameter, 137X its luminosity, 3.3 solar masses, nearly twice as hot as the Sun at ~10600°K
- Double star - 6.8/7.2 magnitudes @ 9.0 arc-seconds, @ 132X primary looks blue-white, the secondary has a warmer color, the pair is part of an obtuse triangle going from primary to 10th mag. star then turning 120° to an 8th mag. star, good separation and some brightness contrast, this one is worth observing, the primary is 11500°K twice as hot as the Sun, 5.3X its diameter & 431X its luminosity, 3.8X the mass, so it's big bright & hot
- Double star - 8.3/8.4 magnitudes @ 1.9 arc-seconds, @ 132X there it is - two faint stars next to each other with a little dark sky between 'em, nice tight star images, no discernible brightness difference, there are a few stars on the very edge of the FOV, increasing to 264X spreads them out further, these components are faint, but with nice star images, seeing is pretty decent, there's one 11th mag. field star on the very edge, but this is a nice faint close pair which has been enjoyable observing, the primary has 13 times the Sun's luminosity
- Double star - 7.0/8.3 magnitudes @ 8.6 arc-seconds, @ 132X the primary has a little bit of orange color to it (C.I. = 1.00), the secondary in contrast looks kind if blue-grey, good brightness contrast & separation, with the bright near full moon sky there aren't any field stars of note, primary is an orange giant spectral type K1, 4660°K (19% cooler than the Sun), 12.4X its diameter, 65X its luminosity, & 1.1 solar masses, this one is well worth observing, a lot of nice contrasts
- Double star - 8.0/8.3 magnitudes @ 2.9 arc-seconds, at this lower 132X power there it is resolved, showing a little difference in brightness, they are separated, it forms a near equilateral triangle with 9th & 10th mag. stars, there's another triangle of field star separate from the 1st triangle (mag. 9, 10 & 11), zooming to 264X puts the second triangle outside the 0.25° FOV, there is some brightness contrast, seeing is remaining pretty decent
- Double star - 7.6/8.3 magnitudes @ 3.9 arc-seconds, this one shows up nicely at the lower 132X power, zooming to 264X there's lots of dark sky between 'em, nice diffraction discs are showing, the secondary gives the sensation of being a little bit red - warmer toned, the double forms an obtuse triangle with 10th & 11th mag. stars, at the double the included angle is around 110°, yeah that reddish color of the secondary is apparent, nice separation, well worth observing, the primary has 441X the energy output of the Sun.
All of these are first time observations, with the exception of Σ 0162.
I was most pleased with the performance of my optimized 8-inch SCT. It was good that seeing allowed for some nice "refractor-like" images. I hope you enjoyed my observations. Please add your observations for comparison.
All the Best,
Edited by Rustler46, 10 December 2022 - 12:41 AM.