|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
145 CMa - the Winter Albireo - a colorful after-work winter double Feb-Mar
145 CMa (HD056577) - the Winter Albireo - is at it's most favorable low
declination position (J071636.00-231912.0) for 41N op's. 145 CMa is visible in small refractors after sunset from urban light polluted skies. The Belmont Society Colorful Double Star List describes pi Gem as "orange/blue-green" while Mullaney's _Celestial Harvest_ gives this double an effusive recommendaton. The primary of this colorful multiple is a v4.8 K4III star at an estimated distance of 536 parsecs. The discover designation - HJ 3945 - attributes first recorded sighting to William Herschel. At 536 parsecs and G236.50-05.22, this double sits west of Canis Major "down-wind" in the Orion Arm from Sol, in a area rich in small open clusters. Current (Epoch 2000) CCDM data on 145 CMa (CCDM 07166-2319) is: C PA sep mag A 4.8 B 055 26.6 6.8 145 CMa is about 3 degs east of omi2 CMa. A courtesy star hopping finder chart is provided at: http://members.csolutions.net/fisher...45StarHops.jpg 145 CMa current is low on the horizon from 41N ops - at about only 20 degrees in altitude at sunset. 145 CMa can be star-hopped or right-angle swept by starting at omi2 CMa. From my light polluted v3.0 urban skies, I began at del CMa and swept north about 3 degs to omi2 CMa. omi2 CMa was just barely naked-eye visible in the light pollution. Due to light pollution, there were really not any good landmarks to star hop to 145 CMa. Finding this double is a bit challenging in light polluted skies. Since 145 CMa is a direct east declination sweep from omi2 CMa, I simply used the lowest feasible magnification, with the largest TFOV, about 1 deg in this case - and then counted about 3 1/2 ep views east of omi2 CMa until I saw a small double that looked like 145's namesake - Albireo. In a small alt-az 60mm refractor under urban Bortle class 8 mag 3.0 light-polluted urban skies at 22x, 145 CMa lives up to its namesake as the Winter Albireo. It is a nice, distinct, intense blue-gold pair about 22" apart. But unlike it's summer namesake, the Winter Albireo is over 500 parsecs distant, while the "real" Albireo is about 125 parsecs away. On increasing magnification to about 78x, the Winter Albireo the colors fade and somewhat dim in a small refractor. In contrast, the bet Cyg double retains is golden-jewel crispness under higher magnification. All-in-all, this was a nice 15-20 minutes of easy after-work beer-in-hand viewing at 41N. The Belmont Society Colorful Double Star list can be found at: http://www.belmontnc.4dw.net/dblstrs.htm - Canopus56 |
#2
|
|||
|
|||
145 CMa - the Winter Albireo - a colorful after-work winter double Feb-Mar
canopus56 wrote:
145 CMa (HD056577) - the Winter Albireo - is at it's most favorable low declination position (J071636.00-231912.0) for 41N op's. 145 CMa is visible in small refractors after sunset from urban light polluted skies. snip Offline, a correspondent "Mike" asked: What catalogs do 145 CMa / HD 056577 appear in? My apologies if the informal designation of Herschel 3945, the Winter Albireo, as 145 CMa, caused more heat than light. I had always learned this binary as "145 CMa," I believe it was from Harrington's TUBA. You are correct to critize the informal desigation of this binary as 145 CMa. As to an authoritative cite, the short answer is that the "A" component (HD56577, HR2764) are cross-referenced in Kostjuk (2002) HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index CDS IV/27 as: HD56577 HR2764 CD-23 5189 HIP35210 ---- 145 CMa ------ http://cdsweb.u-strasbg.fr/viz-bin/Cat?IV/27 One simple method establishing an association between Component A of Herschel 3945 and 145 CMa, is to in "145 CMa" into the CDS Simbad database. http://simbad.u-strasbg.fr/sim-fid.pl Simbad returns a number of cross-references for 145 CMa, including: * 145 CMa ADS 5951 A CCDM J07166-2319A HD 56577 HR 2764 SAO 173349 SKY# 13175 Feeding in the HD designation for the B Component of Herschel 3945 - HD56578 - gives: ** HJ 3945B ADS 5951 B CCDM J07166-2319B CD-23 5192 HIC 35213 HIP 35213 SKY# 13177 As to how CDS Simbad associates 145 CMa with the A Component of Herschel 3945, a more detailed list of catalogue links between Component A and 145 CMa is appended. Again, you are correct to critize the informal designation of this binary as 145 CMa. A better, and admittedly less confusing designation, would have been it's formal discoverer designation - Herschel 3945. From the perspective of non-double star observing amateurs - the intended target of the post - Herschel 3945 is the designation used in the Belmont Society Colorful Doubles List and is the most returned designation from a web engine search on the phrase "Winter Albireo." Personally, I can never seem to remember "HJ3945," while the Flamsteed designation "145 CMa" is more easily remembered. In general, the appropriate method to refer to multiple star systems is by their CCDM (Catalogue of the Components of Double and Multiple Stars) designation, or their discover designation, e.g. HJ3945, **STF761. For informal observing of bright doubles, I prefer to simply remember the Flamsteed or Bayer designation of the star, e.g. sig Ori, pi Gem, zet Per, or 145 CMa. That is technically improper, but it is easier to use when pointing the telescope. This triggered an inquiry to the Starry Night support forum (figured I was doing something wrong), and the response I got was that there are hundreds of catalogs and the developers could not use them all, and they agreed that these numbers are not in the SN database. The software I use is Cartes du Ciel which also does not return 145 CMa, but does position fix on "HD56577". In my defense of the informal designation use, Cartes du Ciel, as installed out-of-the-box, does not return Herschel 3945 either - at least unless specialty supplemental catalogues are installed. I suspect that Starry Night will not return "Herschel 3945" either. As a general note on using various software packages, it is not unusual to have various software package not return positions to the most commonly used catalogue name designations. Alot of time is spent "decoding" designations and finding the one that your software will recognize. Typically, users install add-on catalogues and indices for their area of interest, e.g. DSOs or double stars. From my infrequent use of Starry Night (and hazy recollections my difficulties in using it), for example, out-of-the-box, Starry Night would not find a number of galaxies by NGC number - you had to decode and find the "PGC" Principal Galaxy Catalogue cross-reference number. In conclusion, you are not doing anything wrong. Failed cross-references within a software package is a common problem in the hobby. For DSOs and stars, I find the CDS Simbad database and invaluable tool in that regard: CDS Simbad in Strasbourg, France http://simbad.u-strasbg.fr/sim-fid.pl CDS Simbad mirrored at Harvard, U.S. http://simbad.harvard.edu/Simbad For bright stars, Kostjuk (2002) catalogue ("HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index") is an invaluable resource that I frequently use. I have downloaded a copy of the entire catalogue as an HTML document using the Simbad catalogue service. http://cdsweb.u-strasbg.fr/viz-bin/Cat?IV/27 Then I imported a local copy of the catalogue as an HTML document into Excel and cleaned it up. In conclusion, it is unfortunate that Starry Night and/or Cartes du Ciel do not quickly return a position fix on common references to this beautiful winter binary. It is a colorful binary that is often overlooked by beginners. Hopefully, your web conversations will spur the developers to correct this minor omission. - Regards, Canopus56 Addendum =============== Catalogue linking Herschel 3945 to 145 CMa =============== ---------------- The CCDM links CCDM J07166-2319A to HJ3945, the Winter Albireo's most formal-discover designation, to: CCDMJ07166-2319B and HIC35213 and the A component - HIC35210. http://cdsweb.u-strasbg.fr/viz-bin/Cat?I/274 ---------------- Dommanget, J. The visual double stars observed by the Hipparcos satellite. Astron. Astrophys. 363, 991 (2000) links HJ3945 to: HIP35210 CCDM07166-2319A HIP35213 CCDM07166-2319B http://cdsweb.u-strasbg.fr/viz-bin/Cat?I/260 ---------------- The Hipparcos Input Catalogue, Version 2 (1993) links HIP35210 and HIP3523 provides the following cross-references: HIC35210 BD-23 117 CD -23 5189 HD56577 SAO173349 HIC35213 BD -23 118 CD -23 5192 CPD-23 2015 HD56578 SAO173353 http://cdsweb.u-strasbg.fr/viz-bin/Cat?I/196 ---------------- The Yale Bright Star Catalogue, 5th Revised Ed.(Hoffleit+, 1991) catalogue cross-references HD56577 to: HR2764 ADS5951 http://cdsweb.u-strasbg.fr/viz-bin/Cat?V/50 ---------------- Kostjuk (2002) HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index CDS IV/27 cross-references HR2764 and HD56577 to 145 CMa, as discussed above. http://cdsweb.u-strasbg.fr/viz-bin/Cat?IV/27 |
#3
|
|||
|
|||
145 CMa - the Winter Albireo - a colorful after-work winter doubleFeb-Mar
canopus56 posted:
My apologies if the informal designation of Herschel 3945, the Winter Albireo, as 145 CMa, caused more heat than light. I had always learned this binary as "145 CMa," I believe it was from Harrington's TUBA. You are correct to critize the informal desigation of this binary as 145 CMa. As to an authoritative cite, the short answer is that the "A" component (HD56577, HR2764) are cross-referenced in Kostjuk (2002) HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index CDS IV/27 as: HD56577 HR2764 CD-23 5189 HIP35210 ---- 145 CMa ------ http://cdsweb.u-strasbg.fr/viz-bin/Cat?IV/27 You have no reason to apologize to anyone over this. While h3956 is one of the more common designations for this colorful double star (along with ADS 5951), I have seen it referred to as "145 CMA" from time to time from a variety of sources. Probably the earliest published work I have seen that designation in was David Eicher's book DEEP-SKY OBSERVING WITH SMALL TELESCOPES (1989), so it goes back for a while. I ran into it again when testing my NexStar telescope, as it had 145 CMa listed in its double star database. Whether it is actually an original Flamsteed number is uncertain, as I understand that the highest Flamsteed number within any constellation is 140 (140 Tauri). In any case, the 145 CMa designation is somewhat valuable here, as it it easier to remember than h3945 and tells you instantly what constellation it is in. You also did a valuable service by bringing this "winter Albireo" to the attention of people who might not have hear of it. Clear skies to you. -- David W. Knisely Prairie Astronomy Club: http://www.prairieastronomyclub.org Hyde Memorial Observatory: http://www.hydeobservatory.info/ ********************************************** * Attend the 13th Annual NEBRASKA STAR PARTY * * July 23-28, 2006, Merritt Reservoir * * http://www.NebraskaStarParty.org * ********************************************** |
#4
|
|||
|
|||
145 CMa - the Winter Albireo - a colorful after-work winter double Feb-Mar
David Knisely wrote:
snip In any case, the 145 CMa designation is somewhat valuable here, as it it easier to remember than h3945 and tells you instantly what constellation it is in. snip Thanks David -with the proviso that 145 CMa does not seem to come up in commonly used software packages and beginners that should try the HR or HD designates in their software search boxes: 145 CMa = HD56577 = HR2764 - Canopus56 |
#5
|
|||
|
|||
145 CMa - the Winter Albireo - a colorful after-work winter double Feb-Mar
canopus56 wrote in message:
145 CMa (HD056577) - the Winter Albireo - is at it's most favorable low declination position (J071636.00-231912.0) for 41N op's. snip Canopus56, THANK YOU!! Neither I nor any of the members & visitors attending our public viewing night at the club's observatory had ever seen this beautiful double. Miraculously, we had a completely clear, but cold, night in NE Ohio and took advantage of it. If it weren't for your post, we certainly wouldn't have seen it last night - or perhaps ever. Your subsequent post listing the HD number was also a great service, and much appreciated. Thanks again. Clear Dark Steady Skies, Dave Jessie |
#6
|
|||
|
|||
145 CMa - the Winter Albireo - a colorful after-work winter double Feb-Mar
"Dave Jessie" wrote in message ... canopus56 wrote in message: 145 CMa (HD056577) - the Winter Albireo - is at it's most favorable low declination position (J071636.00-231912.0) for 41N op's. snip Canopus56, THANK YOU!! Neither I nor any of the members & visitors attending our public viewing night at the club's observatory had ever seen this beautiful double. Miraculously, we had a completely clear, but cold, night in NE Ohio and took advantage of it. If it weren't for your post, we certainly wouldn't have seen it last night - or perhaps ever. Your subsequent post listing the HD number was also a great service, and much appreciated. Indeed. I took advantage of the opportunity and the information as well. I even created my own Double Star list in SkyTools and made this the first entry. These are the kinds of reports I want to see more of on SAA. What the heck should we be looking at, that's off the beaten path, on an obscure or even non-existent list? Keep these coming! I need to fill up my Double Star list (and Galaxy, Open Cluster, PN, ...etc.). *** Free account sponsored by SecureIX.com *** *** Encrypt your Internet usage with a free VPN account from http://www.SecureIX.com *** |
#7
|
|||
|
|||
145 CMa - the Winter Albireo - a colorful after-work winter doubleFeb-Mar
Stephn Paul posted:
What the heck should we be looking at, that's off the beaten path, on an obscure or even non-existent list? Well, I don't know about obscure, but here are some of my most favorite color-contrasting double stars: COMMON DOUBLE STARS WITH SIGNIFICANT COLOR CONTRAST (positions, separations, and position angles for 2000) LEGEND: R.A. = Right Ascension (2000.0) Dec. = Declination mag. = apparent visual magnitude sp. = spectral type Sep. = separation (in arc seconds) P.A. = position angle ************************************************** ****************** Eta Cassiopeiae, R.A. 0h 49.10m Dec. +57d 49.0' Primary: mag. 3.4, sp. G0V, Secondary: mag. 7.5, sp. dM0 Sep. 12.8" arc, P.A. 317 deg. (period: 480 years) Colors seen in 10 inch: Off-white and faint reddish-orange. ALMACH (Gamma And.), R.A. 2h 3.90m Dec. +42d 19.8' Primary: mag. 2.2 sp. K3III, Secondary: mag. 4.8 sp. B8V Sep. 9.8" arc, P.A. 64 deg. (mag. 6.3 companion of Gamma-B at 0.4" arc, p.a. 103 deg.). Colors seen in 10 inch: Yellow (Gold) and light blue. 32 Eridani, R.A. 3h 54.29m Dec. -2d 57.3' Primary: mag. 4.5, sp. G8III, Secondary: mag. 6.1, sp. A2V Sep. 6.9" arc, P.A. 348 deg. Colors seen in 10 inch: Yellow and pale blue. 38 Geminorum (STF 982), R.A. 6h 54.64m Dec. +13d 10.7' Primary: mag. 4.7, sp. F0V, Secondary: mag. 7.7, sp. ? Sep. 7.1" arc, P.A. 144 deg. Colors seen in 10 inch: White and faint orangish. h3945 (ADS 5951, CMa), R.A. 7h 16.61m Dec. -23d 18.9' Primary: mag. 4.8 sp. K4III, Secondary: mag. 6.8, sp. F0 Sep. 26.6" arc, P.A. 55 deg. Colors seen in 10 inch: Orange and bluish-white. "The Winter Albireo" Iota Cancri, R.A. 8h 46.70m Dec. +28d 45.6' Primary: mag. 4.0 sp. G8II, Secondary: mag. 6.6 sp. A3V Sep. 30.5" arc, P.A. 307 deg. Colors seen in 10 inch: Light yellow and pale blue. Tau Leonis, R.A. 11h 27.94m Dec. +2d 51.3' Primary: mag. 4.9 sp. G8II, Secondary: mag. 7.4 sp. ? Sep. 89.7' arc, P.A. 180 deg. Colors seen in 10 inch: Yellow and pale bluish-white. *nice low power pair with double 83 Leonis 20' at P.A. 298 deg. 2 Canum Venaticorum, R.A. 12h 16.13m Dec. +40d 39.6' Primary: mag. 5.7, sp. M1III, Secondary: mag. 8.7, sp. F7V Sep. 11.3" arc, P.A. 260 deg (2003). Colors seen in 10 inch: Yellowish-orange and pale bluish. 24 Comae Berenices, R.A. 12h 35.13m Dec. +18d 22.6' Primary: mag. 5.0 sp. K2III, Secondary: mag. 6.6 sp. A7V Sep. 20.3" arc, P.A. 271 deg. Colors seen in 10 inch: Yellow and pale blue. Cor Caroli (Alpha CVn), R.A. 12h 56.00m Dec. +38d 19.1' Primary: mag. 2.9 sp. A0spe, Secondary: mag. 5.6, sp. F0V Sep. 18.8" arc, P.A. 230 deg. Colors seen in 10 inch: Bluish-white and off-white (cream). Izar (Epsilon Bootis), R.A. 14h 44.99m Dec. +27d 4.5' Primary: mag. 2.4 sp. K0II, Secondary: mag. 5.1, sp. A2V Sep. 2.8" arc P.A. 339 deg. Colors seen in 10 inch: Yellow and light blue. Xi Bootis, R.A. 14h 51.39m Dec. +19d 6.0' Primary: mag. 4.5, sp. G8V, Secondary: mag. 6.8, sp. K5V Sep. 6.8" arc P.A. 320 deg. Colors seen in 10 inch: Pale yellowish white and orange. Antares (Alpha Sco). R.A. 16h 29.41m Dec. -26d 25.9' Primary: mag. 1.0v sp. M1I, Secondary: mag. 5.4 sp. B4 Sep. 2.6" arc P.A. 274 deg. Colors seen in 10 inch: Orange and light blue. Ras Algethi (Alpha Her) R.A. 17h 14.65m Dec. +14d 23.4' Primary: mag. 3.2v sp. M5II Secondary: mag. 5.4, sp. F2/G3 Sep. 4.6" arc P.A. 104 deg. Colors seen in 10 inch: Reddish-orange and pale bluish-white. Omicron Ophiuchi, R.A. 17h 18.00m Dec. -24d 17.2' Primary: mag. 5.1, sp. K.. Secondary: mag. 6.6, sp. ? Sep. 10.3" arc, P.A. 355 deg. Colors seen in 10 inch: Yellow and pale blue. SHJ 282 (ADS 11834, Lyra), R.A. 18h 54.90m Dec. +33d 58.0' Primary: mag. 6.1, sp. G8 Secondary: mag. 7.7, sp. A1 Sep. 45.4" arc P.A. 350 deg. Colors seen in 10 inch: Yellowish-white and bluish-white. Albireo (Beta Cyg) 19h 30.72m Dec. +27d 57.6' Primary: mag. 3.1 sp. K3II Secondary: mag. 5.1 sp. B8V Sep. 34.3" arc P.A. 54 deg. Colors seen in 10 inch: Yellow and light blue. ADS 12900 (Cyg). 19h 45.86m Dec. +35d 0.77' Primary: mag. 6.1 sp. K2? Secondary: mag. 8.6 sp. A2V Sep. 37.5" arc P.A. 25 deg. Colors seen in 10 inch: Yellow and blue. Gamma Delphini, R.A. 20h 46.73m Dec. +16 deg. 7.8' Primary: mag. 4.2 sp. G5V, Secondary: mag. 5.2 sp. F8V. Sep. 9.6" arc P.A. 268 deg. Colors seen in 10 inch: Yellowish and white (hint of blue)? Delta Cephei R.A. 22h 29.20m Dec. +58d 25' Prmary: mag. 4.07 (variable) sp. F5-G3 Secondary: mag. 6.27 sp. B7 Sep. 40.8" arc P.A. 191 deg. Colors seen in 10 inch: Yellowish-white and light blue. Clear skies to you. -- David W. Knisely Prairie Astronomy Club: http://www.prairieastronomyclub.org Hyde Memorial Observatory: http://www.hydeobservatory.info/ ********************************************** * Attend the 13th Annual NEBRASKA STAR PARTY * * July 23-28, 2006, Merritt Reservoir * * http://www.NebraskaStarParty.org * ********************************************** |
#8
|
|||
|
|||
145 CMa - the Winter Albireo - a colorful after-work winter doubleFeb-Mar
David Knisely wrote:
Stephn Paul posted: What the heck should we be looking at, that's off the beaten path, on an obscure or even non-existent list? Well, I don't know about obscure, but here are some of my most favorite color-contrasting double stars: COMMON DOUBLE STARS WITH SIGNIFICANT COLOR CONTRAST (positions, separations, and position angles for 2000) Clear skies to you. Hi Thanx from me too -- AM http://sctuser.home.comcast.net CentOS 4.2 KDE 3.3 |
#9
|
|||
|
|||
145 CMa - the Winter Albireo - a colorful after-work winter double Feb-Mar
"David Knisely" wrote in message ... Well, I don't know about obscure, but here are some of my most favorite color-contrasting double stars: COMMON DOUBLE STARS WITH SIGNIFICANT COLOR CONTRAST Excellent! Thanks David. -Stephen *** Free account sponsored by SecureIX.com *** *** Encrypt your Internet usage with a free VPN account from http://www.SecureIX.com *** |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Ted Taylor autobiography, CHANGES OF HEART | Eric Erpelding | Policy | 3 | November 14th 04 11:32 PM |
transportation revolution at hand | Raheman Velji | Misc | 2 | November 13th 04 05:18 PM |
disaster warning | Anonymous | Astronomy Misc | 1 | January 23rd 04 09:31 PM |
First Double Star satellite successfully launched (Forwarded) | Andrew Yee | Astronomy Misc | 0 | December 29th 03 11:35 PM |
Electric Gravity&Instantaneous Light | ralph sansbury | Astronomy Misc | 8 | August 31st 03 02:53 AM |