This report is the second installment of a series of observational investigations I have made using an 8 inch f/5.9 reflecting telescope.
Check out this link for goals and methods used in this study:
https://www.cloudyni...-and-monoceros/
Gemini
STT 149 (06364+2717) mags 7.14/8.97; pa = 277°; sep = 0.733”, orbital estimate for 2019.3 (grade 2 data not a great match to historical 4th Int. Cat. data or last precise)
627x: at times pointy but that’s it; below resolution limit; yearly separation change is significant (components are closing); requires independent (possibly annual) measure of separation
COU 930 (07566+1954) mags 9.10/9.29; pa = 330°; sep = 0.583”, 2008 (data is old)
345x: single star
460x: at times slightly elongated, but that’s it; below resolution limit; requires re-measure of separation
A 2726 (06293+1233) mags 9.03/9.27; pa = 123°; sep = 0.550” (2015.5, Gaia DR2) vs 0.65”, 2015 (last precise)
345x: elongated rod which resolves to two discs of slightly dissimilar magnitude 25% of time; appears to be at resolution limit which supports 0.65” value for separation; 4th Int. Cat. data does not help to clarify the situation; requires re-measure of separation to solidify this value
A 2464 (07046+1550) mags 9.13/9.78; pa = 40°; sep = 0.73”, 2016 (scant data)
345x: persistently notched rod
460x: persistent as snowman shape with slightly dissimilar magnitudes that resolves to two discs 40% of time; just above resolution limit; separation re-measure needed
A 2868 (07292+1253) mags 8.59/8.98; pa = 22°; sep = 0.677”, 2015.5 (Gaia DR2, solid data)
552x (Pentax 2.5XO + Paracorr Type 1, setting 1): definitely pointy but too faint for Airy discs to be seen as distinct points of light; never resolved—just below resolution limit (will revisit next year using powermate/plossl optical train)
Bu 1008 Propus (06149+2230) mags 3.52/6.15; pa = 252°; sep = 1.78”, 2017 (solid data)
345x: just split, secondary is much smaller
460x: easier to see as split; above resolution limit
Leo
STF 1423 (10192+203) mags 9.40/10.03; pa = 300°; sep = 0.600”, 2019.3 (orbital estimate; scant data)
as yet unobserved; requires a re-measure of separation to solidify value
STF 1555AB (11363+2747) mags 6.41/6.78; pa = 151°; sep = 0.79”, 2017 vs 0.666”, 2019.3 orbital estimate
460x: vacillates between snowman shape and resolved with discs of slightly dissimilar magnitude
627x: pushes past resolved to split 10% of time; observation supports 0.66” value for separation; 4th Int. Cat. supports a value of less than 0.79”; requires re-measure of separation to solidify value
STF 1356 (09285+0903) mags 5.69/7.28; pa = 114°; sep = 0.878”, 2019.3 (orbital estimate; solid data)
345x: just split to two yellow stars of even magnitude; above resolution limit
A 2482 (09599+1610) mags 9.26/10.07; pa = 47°; sep = 0.85”, 4th Int. Cat. estimate (data is scant, divergent)
345x: seen as just split 40% of time; at edge of visibility due to faintness; secondary is much smaller and barely presents as a disc; just above resolution limit; requires re-measure of separation
Bu 105AB (09247+2611) mags 4.60/9.70; pa = 209°; sep = 1.960”, 2015.5 (Gaia DR2; solid data)
230x: fairly challenging; seen as split about 50% of time with secondary as very small dot quite close to the primary; above resolution limit
Orion
Bu 885 (05110-0146) mags 8.31/9.01; pa = 198°; sep = 0.601”, 2017 (solid data)
345x: extremely difficult; at most slightly elongated
460x: moves past elongated to a snowman shape about 20% of time
627x: elongated only despite best effort; this object is a bit below the resolution limit
Bu 318 (05162-0329) mags 8.81/8.28; pa = 264°; sep = 0.643”, 2017 (solid data)
345x: single star
460x: pointy at times
627x: moves past elongated to resolved using averted vision 25% of time; right at resolution limit
A 321 (05568-0304) mags 9.02/10.03; pa = 134°; sep = 0.645”, 1995 (data is old)
345x: pair is very faint; elongated ~entire time; resolved to two tiny dots <5% of time; at resolution limit; requires re-measure of separation
A 2717AB (06152+0631) mags 8.07/8.98; pa = 354°; sep = 0.60”, 4th Int. Cat. estimate (data is old)
345x: pointy only
460x: moves past elongated to resolved 50% of time; requires very good seeing because components are faint; just above resolution limit—separation likely greater than 0.60”; requires re-measure of separation
STT 517AB (05135+0158) mags 6.79/6.99; pa = 240°; sep = 0.693”, 2017 (solid data)
394x (Pentax 3.5XW, Paracorr Type 1, setting 1): moves past snowman shape to resolved when seeing allows; above resolution limit
DA 4Aa,B (05354-0450) mags 4.61/7.50; pa = 203°; sep = 1.207”, 2015.9 (data is solid)
460x: seen steadily as just split ~entire time
627x: secondary visible 100% of time as small white dot easily split from primary; above resolution limit;
I have observed this object (aka 42 Ori) dozens of times over the past 8 years and this was the clearest view I had ever had of the secondary—this result spurred me to change up my preferred double star eyepieces to the currently used tandem of powermate/plossl and also to initiate a detailed study of similarly challenging binaries
Bu 190AB (05204-0802) mags 8.12/8.45; pa = 328°; sep = 0.647”, 2015.5 (Gaia DR2, solid data)
627x: secondary pops into view as resolved 20% of time; at resolution limit
STT 119 (05479+0758) mags 8.08/8.93; pa = 355°; sep = 0.706”, 2015.5 (Gaia DR2, needs a confirming measure)
460x: mostly seen as split to two stars of uneven magnitude; above resolution limit; while the Gaia separation value ‘seems right’, this binary requires a separation re-measure due to conflicting 4th Int. Cat. data
STF 652 (05118+0102) mags 6.26/7.44; pa= 180°; sep = 1.667”, 2015.5 (Gaia DR2, solid data)
460x: brightening of first diffraction ring that sharpens 50% of time to a small secondary seen as split from the primary
627x: more easily seen as split when seeing allows; above resolution limit; something odd here: this object is surprisingly difficult, possibly due to the proximity of the secondary to the first diffraction ring (?); will likely re-measure separation to get more info
DA 3 (05359-0538) mags 7.33/8.54; pa = 173°; sep = 0.860”, 2015.5 (Gaia DR2, solid data)
345x: snowman
460x: just split to two stars of uneven magnitude 30% of time
627x: more easily seen as split when seeing allows; above resolution limit
STF 728 (05308+0557) mags 4.44/5.75; pa = 44°; sep = 1.281”, 2015.5 (Gaia DR2, solid data)
345x: just split to two white stars of uneven magnitude; above resolution limit
HEI 670 (05500+0952) mags 5.97/8.36; pa = 264°; sep = 1.093”, 2011 (solid data)
345x: brightening of first diffraction ring sharpens to a small secondary seen as just split 20% of time
460x: more easily seen as split when seeing allows; above resolution limit
Gaia DR2 detects a star at pa = 268° but with a separation of only 0.438”. Observations seem to confirm separation of 1.09” vs 0.44”—could this be a triple system? Will image to get more information
Bu1052 (05417-0254) mags 6.68/8.22; pa = 183°; sep = 0.649”, 2019.3 orbital estimate (solid data)
345x: pointy (snowman) shape
460x: vacillates between elongated and resolved to two discs
627x: moves past resolved to split 10% of time; above resolution limit; surprisingly easy considering the separation and delta mag; perhaps the binary is in a ‘sweet spot’ for this telescope (?) Should probably re-measure separation to get more info
STF 734AB (05331-0143) mags 6.67/8.22; pa = ; sep = 1.585”, 2015.5 (Gaia DR2, solid data)
345x: easily split; smaller secondary is perhaps ashen in color
Puppis
B 1074 (07451-2855) mags 9.44/9.79; pa = 357°; sep = 0.56”, 1991 (data is old)
as yet unobserved; will need an independent measure
STF 1104AB (07294-1500) mags 6.39/7.60; pa = 40°; sep = 1.790”, 2019.3 (orbital estimate; solid data)
345x: easy, wide split to two somewhat dissimilar magnitude white stars
Bu 454AB (08159-3056) mags 6.50/8.21; pa = 359°; sep = 1.847”, 2015.5 (Gaia DR2; solid data)
345x: split 100% of time; considerable magnitude contrast; primary is yellow while the secondary may be light orange
STF 1146 (07479-1212) mags 5.73/7.32; pa = 336°; sep = 1.010”, 2019.4 (orbital estimate; solid data)
345x: easy split; fine magnitude contrast pair with both stars appearing yellowish-white
Have you observed any of these objects recently? Let me know. Or, perhaps you have a suggestion for a double I should observe—I’m all ears!
Edited by Nucleophile, 12 June 2019 - 08:13 AM.
