11 replies to this topic

[Rustler46]

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.

 

Date/Location: 

2022-December-6
Ocean Observatory, Coos Bay, Oregon

 

Conditions:

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

 

Telescope:

​Celestron-8, f/10, 2032 mm focal length
Magnifications mostly 132X to 264X, using APM Superzoom

 

Notes:

• 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 

 

Observations:

 

Omicron Persei

• 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

HU 544

• 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

Σ 0162

• 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

Σ 0268

• 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

Σ 0369

• 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

Σ 0552

• 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

Σ 0272

• 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

Σ 0336

• 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

Σ 0360

• 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

Σ 0391

• 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,

Russ

Edited by Rustler46, 10 December 2022 - 12:41 AM.

[R Botero]

Great session Russ!   Some lovely objects in it.  Atik is a difficult one; my last observation was in January this year with my 10" f/20 Mak.  HU544 is another toughie; my notes from November 2016 were:  PA100, white and pale blue.  My notes for Struve 162 from last January were "Great triple.  DRs around AB.  PA190-200.  C due S".  For Struve 268, my latest notes are from December 2018, "White yellow primary and white blue secondary at PA130".  I have not observed Struve 552 but my notes for 272 from November 2016 were simply "cat's eyes and PA200".

 

Roberto

[SebastianTS]

Hi Russ and all others,

 

after a full month of no opportunity to observe I finally had a clear night yesterday. Plus it was the first night of decent conditions for my new 102mm f/11 ED.

Since Perseus is  in a perfect position from my terrace, I took the liberty to use Russ' list as a guide for my session.

 

STF 336. Wonderful view at 56x and 90x! A orange, B white, nice color contrast. Separation quite easy even at 56x.

 

STF 360. A gem again! At 56x maybe still touching, beautifully split at 90x. A yellowish white, B white. The nearby stars form a conspicuous arc-shaped pattern. Within this arc I noticed two other pairs. The first one turned out to be WZ 6 (Wirtz), mags 11.0 and 11.2 at 7". At 134x they appeared clearly as not a single star, but I could discern them only by using averted vision. The second one is STF 361, mags 9.0 and 11.0 at 10.2". At 134x B was seen using averted vision and for short moments I could hold B with direct vision. Quite dimm.

 

STF 369. Very tight split at 56x, better at 90x. Both appeared cold white. Very nice separation, grand view!

 

STF 391. Similar situation, very tight split at 56x and clear black line at 90x. Both golden and quite similar in brightness. Superb, also at 134x! In the same FOV I discovered another dim pair, turned out to be  SKF 2401 (Skiff), mags 10.1 and 10.9 at 15.8". At 134x A and B visible with direct vision, but very dim, of course.

 

STF 272. At 90x elongated, 134x was enough for a clean split, more distinct, however, at 178x. Both stars look identical in color (yellowish white) and brightness.

 

STF 258. A distinct difference in brightness. At 90x B popped in, better at 134x. Nice!

 

STF 162. Awesome scene ! A, B, and C in almost a straight line, brightness gradually decreasing from A to C. The AB pair (1.9") is much tighter than BC (19.1"), however. At 90x AB elongated, good split at 134x. At 178x I could glimpse very subtle diffraction rings.

 

It was a very successful and exciting session although it was very cold, temperature dropped to -7C (19.4F)

Thank you very much, Russ, for this awesome compilation .

 

CS,

 

Sebastian

[Rustler46]

Hi Russ and all others,

 

after a full month of no opportunity to observe I finally had a clear night yesterday. Plus it was the first night of decent conditions for my new 102mm f/11 ED.

Since Perseus is  in a perfect position from my terrace, I took the liberty to use Russ' list as a guide for my session.

 

STF 336. Wonderful view at 56x and 90x! A orange, B white, nice color contrast. Separation quite easy even at 56x.

 

STF 360. A gem again! At 56x maybe still touching, beautifully split at 90x. A yellowish white, B white. The nearby stars form a conspicuous arc-shaped pattern. Within this arc I noticed two other pairs. The first one turned out to be WZ 6 (Wirtz), mags 11.0 and 11.2 at 7". At 134x they appeared clearly as not a single star, but I could discern them only by using averted vision. The second one is STF 361, mags 9.0 and 11.0 at 10.2". At 134x B was seen using averted vision and for short moments I could hold B with direct vision. Quite dimm.

 

STF 369. Very tight split at 56x, better at 90x. Both appeared cold white. Very nice separation, grand view!

 

STF 391. Similar situation, very tight split at 56x and clear black line at 90x. Both golden and quite similar in brightness. Superb, also at 134x! In the same FOV I discovered another dim pair, turned out to be  SKF 2401 (Skiff), mags 10.1 and 10.9 at 15.8". At 134x A and B visible with direct vision, but very dim, of course.

 

STF 272. At 90x elongated, 134x was enough for a clean split, more distinct, however, at 178x. Both stars look identical in color (yellowish white) and brightness.

 

STF 258. A distinct difference in brightness. At 90x B popped in, better at 134x. Nice!

 

STF 162. Awesome scene ! A, B, and C in almost a straight line, brightness gradually decreasing from A to C. The AB pair (1.9") is much tighter than BC (19.1"), however. At 90x AB elongated, good split at 134x. At 178x I could glimpse very subtle diffraction rings.

 

It was a very successful and exciting session although it was very cold, temperature dropped to -7C (19.4F)

Thank you very much, Russ, for this awesome compilation .

 

CS,

 

Sebastian

So pleased you had a clear albeit cold night for observing doubles. Your observation of SKF 2401 brings to mind that wide faint pairs are easier than close faint ones. Averted vision may be needed to see the faint components. If close, then direct vision is needed to see the split. But then the components become less visible. This is part of the challenge in the wide variety to be found in our targets.

 

Where is SW Germany are you located? I'll stop by and say Hi via Google Earth.

 

CS,

Russ

Edited by Rustler46, 13 December 2022 - 07:22 PM.

[SebastianTS]

Right, these faint doubles are much more challenging, especially in strongly light polluted skys.

 

 

Where is SW Germany are you located? I'll stop by and say Hi via Google Earth.

 

CS,

Russ

I live in Stuttgart, some 10 kilometers south west of the center. 

 

CS, Sebastian 

[Rustler46]

Right, these faint doubles are much more challenging, especially in strongly light polluted skys.

 

I live in Stuttgart, some 10 kilometers south west of the center. 

 

CS, Sebastian 

Wow, Sebastian. It looks like you have a beautiful place to live. That very large forested area must contribute to some relatively dark skies viewing in the southwest. I lived near Frankfurt (Hanau) for almost 2 years starting in 1970. Germany is such a beautiful, well cared for country.

 

Tonight promises to be clear and relatively cold for the Oregon coast. Cold for me means below freezing. It is a bit uncomfortable for extended observing sessions, but nothing like what others endure. I hope to observe a list of doubles in Taurus.

 

All the Best,

Russ

[SebastianTS]

Russ, according to the images I found on Google Maps of Coos Bay, you live at a quite beautiful place yourself! Compared to the wonderful coast line the forest around Stuttgart is rather dull .

Interesting fact, that you lived in Germany! Although I was not even born in the 1970s .

I have never been in the US.

 

As for light pollution, Stuttgart is so bright, that you can easily see a glowing dome from a distance of 30km or more. I live a little bit outside of the center, but it still counts as Bortle 5 (19.70 mag./arc sec2, lightpollutionmap.info). According to that web site, you have Bortle 2 in range from your location! Do you take advantage of that option? Is there a suitable place to observe in the mountains east of Coos Bay?

 

Hope you had a clear night at Oregon coast!

 

CS, Sebastian

[Rustler46]

Russ, according to the images I found on Google Maps of Coos Bay, you live at a quite beautiful place yourself! Compared to the wonderful coast line the forest around Stuttgart is rather dull .

Interesting fact, that you lived in Germany! Although I was not even born in the 1970s .

I have never been in the US.

 

As for light pollution, Stuttgart is so bright, that you can easily see a glowing dome from a distance of 30km or more. I live a little bit outside of the center, but it still counts as Bortle 5 (19.70 mag./arc sec2, lightpollutionmap.info). According to that web site, you have Bortle 2 in range from your location! Do you take advantage of that option? Is there a suitable place to observe in the mountains east of Coos Bay?

 

Hope you had a clear night at Oregon coast!

 

CS, Sebastian

Thanks Sebastian. I did have a clear, cool night for a few doubles in Pisces. As for forests, I recall those in Germany were working forests. Having worked in forestry for some 25 years, I appreciate that there are natural forests and those in a more "managed" condition. While Oregon has some beautiful natural forests, many of its forests are industrial forests - managed to produce wood products. Some call Oregon "the land of the clearcut". But in my part of the world industry gives me access to dark sites via all the logging roads. Here's a Bortle 3 site a bit over an hour from home.

 

C-8 set up for a Transit of Mercury 

 

Russ with smoke from forest fire

 

The above Bortle 2 site is about 1-1/3 hours from home. At my location in Coos Bay the skies are usually around Bortle 5. Sometimes when infrequent dry air is aloft it can approach Bortle 4. At such times I can see the Milky Way extending across most of the sky. We all observe under differing conditions.

 

All the Best,

Russ

Edited by Rustler46, 16 December 2022 - 12:53 AM.

[John Fitzgerald]

<snip>

 

Observations:

 

Omicron Persei

• 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.

I have not tried this one.  It would be too difficult for my 6 inch apo, in all except the best seeing here. I will try if seeing allows.

 

HU 544

• 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.

I split this one on 11/22/2022.  My notes say it is tight, unequal,  split at 243x. 

 

Σ 0162

• 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.

I most recently observed STF 162 on 10/31/2022.  I saw all three components at 152x. 

 

Σ 0268

• 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.

Split this one on 12/03/2019, using a 7mm Delite for 173x, 6" f/8 apo.

 

Σ 0369

• 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

Observed on 11/15/2020, well split at 173x.

 

Σ 0552

• 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

Observed on 12/20/2022 at 81x, using a 15mm Delite, nicely split.

 

Σ 0272

• 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

Split this one on 12/03/2019, using a power of 173x.

 

Σ 0336

• 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

I noted this as a nice pair on 11/06/2020, very well split at 173x.

 

Σ 0360

• 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

I noted this as a very nice pair, nicely split at 173x on 11/06/2020.

 

Σ 0391

• 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.

This one (STF 391) was easily split at 173x on 11/15/2020.

 

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,

Russ

Note: I had to go back and edit, after pausing to find some more notes.

 

My observations are shown under Russ's, in bold italic fonts.

 

My notes are not as extensive as Russ has on his observations.  I merely note when split, scope, and magnification on my observation sheet.  If seeing is particularly good or bad, I note that also.  For unusual pairs, I note it as exceptional.  I sometimes make a sketch.  I usually don't see much color in the doubles I observe.

Russ, thanks for the excellent notations. I need more room on my note sheets.

Edited by John Fitzgerald, 21 December 2022 - 11:43 AM.

[Rustler46]

Note: I had to go back and edit, after pausing to find some more notes.

 

My observations are shown under Russ's, in bold italic fonts.

 

My notes are not as extensive as Russ has on his observations.  I merely note when split, scope, and magnification on my observation sheet.  If seeing is particularly good or bad, I note that also.  For unusual pairs, I note it as exceptional.  I sometimes make a sketch.  I usually don't see much color in the doubles I observe.

Russ, thanks for the excellent notations. I need more room on my note sheets.

Your kind comments are much appreciated, John. I'm pleased some others find my at-the-eyepiece ramblings to be of use. They are by no means scientific. Eventually I'll start making more definite observations of rough position angles. But more accurate PAs are no longer possible, since I sold my Celestron Micro-Guide Eyepiece. I do enjoy taking some time at each double star to see how the view develops with changes in seeing and as my own perceptive powers kick in over time.

 

I appreciate how you've inserted your observations right next to mine in a different color. That's something I'll do in the future when commenting on others' observations. I do recommend using a voice recorder at the eyepiece. What is said can be transcribed into a digital record with editing for clarity and less redundancy. My "Astronomical Observations" Excel spreadsheet has around 4500 entries. Many of these came from the first 40 years or so, when I wrote brief observations with ball-point pen on soggy paper in a journal. Here's a screen-shot of part of the record sorted by object name.

 

 

This shows both of the records for STF 162. The highlighted cell colors are of no significance in our discussion. Column G contains the single cell observation notes, that can be quite an extensive paragraph. The column headings show a little down-arrow that allows for sorting by that parameter, either ascending or descending. The two sorts I use are by date or object type. One could also sort by instrument (telescope) type, aperture (Inches) or object observations. I've begun beginning all observations with the type of object, in this case Double Star. Thus all the double star observations can be shown together by that sort. If anyone wants the spreadsheet for their use I can send via PM. The only thing of use would be the column headings with sort capability. Anyone with much skill in Excel spreadsheets can do the same. I used to use Astroplanner  software for the same thing.

 

With a go-to mount it is all too easy to take a quick look at a large number of objects without really enjoying the view of each one. I have noticed when there is a slight difference in color between primary and secondary, the perceived colors seem to switch back and forth between the pair. Sometimes A is a little warmer colored. Then bit later the opposite is seen. Have others noted a similar effect?

 

Best Regards,

Russ

Edited by Rustler46, 21 December 2022 - 06:08 PM.

[John Fitzgerald]

Russ,

For some reason, I usually perceive most double stars as white, with notable exceptions.   When there is a faint companion visible by direct vision, I often pursue it as gray or blue, often in error.

[Rustler46]

Russ,

For some reason, I usually perceive most double stars as white, with notable exceptions.   When there is a faint companion visible by direct vision, I often pursue it as gray or blue, often in error.

I've noticed the same tendency for a fainter secondary to look grey-blue compared to the primary. It seems like perceived colors of stars are inconsistent between different observers. Looking at Web's Celestial Objects for Common Telescopes from the 1800s describes a lot of colors seen with relatively small apertures. Many of these are seen differently by different observers. Haaz's Double Stars for Small Telescopes has another take on star colors. I guess the final word is provided by the spectroscope.

 

Russ