601 replies to this topic

[clastro8*]

Tau Leo 11 27 2 51, 5.1/7.5, 89", 182*

 

I found Tau as the brightest in a pretty arc of dimmer stars but I wasn't able to see the companion either with 15x or 22x.

 

I think Bortle keeps me from seeing stars in the mid 7 to higher mag range, that's my experience so far anyway.  For example, I've seen the companion for Gemini Zeta (mag 7.7) only once on a very clear night, even though I looked for it many times over the last couple of years.

 

Close to Tau I did observe a very faint star that I 'wanted' to think is the twin but the PA wasn't close and the separation much greater.  To see it I mostly had to use averted vision and was a little surprised that worked even for 10x magnification.

 

From looking at Star Safari, I think the faint star is HD99739 with mag 7.25 and measures about a half degree from Tau, which is much greater than 89".  At mag 7.25, it would be 26% brighter than the companion, so if I have to use averted to see it, it is reasonable to think I can't see the companion which is quite dimmer and also very close to Tau.

 

I'll be trying again but am not too disappointed especially if my analysis of why I couldn't see it last night is correct.

Edited by clastro8*, 16 April 2023 - 03:50 PM.

[Fiske]

What is your Bortle estimate for your skies, clastro?

 

[clastro8*]

Hi, Fiske, I think it's Bortle 7 and the app Clear Outside says I have 18.93 sky quality.  Using the Astro League technique of counting Ursa Minor stars naked eye, rarely it's 3, usually 2 and sometimes 1, which isn't great.   I realize my less than perfect eyesight may be a factor, too, which I should have mentioned earlier.

 

I've seen some of the narrower separations, for example, you mentioned S3945 above, that's 27", I've been able to see it, but it's a lot brighter.

Edited by clastro8*, 16 April 2023 - 06:26 PM.

[Fiske]

I'm sorry to hear about your vision problems, Clastro. I wonder if a telescope might be a better option for you?

 

At any rate, thank you for mentioning Tau Leo, it is a fine binocular double star and accompanied by a second double (83 Leo) in the pretty arc of stars you pointed out. Here are my observations of them from Sunday night, 16 April 2023.

 

The double stars STFA 19 / Tau Leo and STF 1540 / 83 Leo, adjacent to each other in a graceful arc of stars, are one of the binocular glories in Leo, and easily seen in bright suburban skies. Not to be missed!

 

STFA 19 / Tau Leo

11h27m +02*51'
5.05/7.47 sep 89.2" pa 181*

 

100XL-SD+14XWs (40x)

Gorgeous! White gold primary with a pale blue companion at a generous distance.

 

STF 1540 / 83 Leo

11h26m +03*01'
6.55/7.50 sep 28.6" pa 146*

 

100XL-SD+14XWs (40x)

White primary with a sand colored companion at a comfortable distance. What a fine field! A fantastic view with the 20x70 ED Ultra. Also easily resolved with the Oberwerk 12x50 SE.

 

And here is additional binocular double star bounty from my observing session in Leo on Sunday night.

 

STF 1487 / 54 Leo

10h55m +24*45'
4.48/6.30 sep 6.6" pa 112*

 

100XL-SD+14XWs (40x)

Brilliant white primary with a diminutive light yellow companion hovering at its side. Beautifully resolved.

 

STF 1552 / 90 Leo

11h34m +16*48'
AB 6.26/7.31 sep 3.1" pa 209*
AC 6.26/9.77 sep 63.4" pa 235*

 

100XL-SD+14XWs (40x)

The AB components are extremely tight. Resolved by a hair. A fine hair. Both stars white. The C component can be seen to the west. Distinctly orange.

 

STF 1547 / 88 Leo

11h31m +14*22'
6.33/9.14 sep 15.34 pa 332.2*

 

100XL-SD+14XWs (40x)

Warm white primary with a tan secondary to the north at a close but comfortable distance. I could not resolve this with the 20x70 ED Ultra while standing, but was able to resolve it later from a seated position with the tripod tilted back.

 

HJ 2583

11h43m +13*31'
9.71/9.92 sep 33.4" pa 62*

 

A faint, evenly matched pair of white stars east and a little south of Denebola. Ho hum.

 

STF 1565

11h39m +19*00'
7.26/8.41 sep 22.2" pa 304*

 

Just north and a little east of 90 Leo. Warm white primary with a sand colored secondary. Close but not tight with the 20X70. Challenging but fully resolved with the 12x50 SE and the Vortex 12x50 Razor UHD. A nice addition to my Leo double star list.

Edited by Fiske, 18 April 2023 - 06:28 AM.

[Fiske]

I recently started working on a list of closer double stars for 10x binoculars (created from StelleDoppie) and observed a few of them last Saturday evening, 22 April 2023. Additional details about the observing project (and the list itself) are included in this ExploreTheNightSky blog post. 

 

One of the doubles I tried last Saturday is a fine catch for binoculars in the 15-20x range.

 

STF 1321
09h14m +52*41′
7.79/7.88 sep 17″ pa 99.5*
Physical double star

 

At 10x STF 1321 appears as a pair of ivory-colored stars, nearly in contact. But with the 15×70 the stars are seen as deep yellow. Maybe apricot. One of the highlights of the evening. Easily found in the Talitha leg of Ursa Major, between two bright field stars (18 and 15 UMa) west of Theta and 26 UMa. Considerably easier to resolve with 12x binoculars compared to 10x, BTW.

 

 

Edited by Fiske, 28 April 2023 - 06:52 PM.

[TJNOCMAN]

Fiske,

 

I really enjoy reading your blog. What I like about it most is I always learn something, without the feeling that I am exhausted from the process. Your writing tempo, and style makes for a good read. Thank you for your work. TJ

[Fiske]

Fiske,

 

I really enjoy reading your blog. What I like about it most is I always learn something, without the feeling that I am exhausted from the process. Your writing tempo, and style makes for a good read. Thank you for your work. TJ

Thank you, TJ. What a nice compliment! 

 

I've just updated the logo with a wonderful design by Rimma Dikikh, an illustrator and lettering artist from Malta. 

Edited by Fiske, 29 April 2023 - 09:46 AM.

[Regulus 1.36]

You all should try the Binocular Double Star Challenge by the Astronomical League. At the very least, you'll know what's available to binoculare users within that category.  https://www.astrolea...ms/BinoDS_Intro

[Fiske]

Thanks, Reg. 

 

I did the AL Double Star program years ago. Even sketched every double on preprinted forms I created with a desktop publishing merge application.   Now all organized in a cute 6x9 binder. These nights I prefer to make my own lists. 

Edited by Fiske, 30 April 2023 - 03:35 PM.

[Regulus 1.36]

Thanks, Reg. 

 

I did the AL Double Star program years ago. Even sketched every double on preprinted forms I created with a desktop publishing merge application.   Now all organized in a cute 6x9 binder. These nights I prefer to make my own lists. 

I was mostly referring to the 99% of bino users who read this post. That link has a lot more than just double stars within the website too. 

[clastro8*]

Hi, Fiske, I would really like to see one of the sketches you made that is mentioned above.  Could you post a copy here?

[Fiske]

Here is my sketch of Porrima in Virgo, made on May 30, 2002. 

 

 

It's a bit closer now.

 

STF 1670 / Porrima
12h41m -01*27'
3.48/3.53 sep 3.05" pa 356.2*

 

It's interesting to me that it was difficult at 280x. A separation of 3.6" for such evenly matched stars doesn't sound that challenging at this point. They might be difficult for a BT because they are so bright, but I wouldn't expect to have trouble resolving it with the Orion CC8 Cassegrain at 170x, even at the closer 3" separation. Will have to give that a try now.   

 

And look how much the PA has changed in 21 years too. I guess the orbital period is 168.68 years, which is really short for a visual double star. It's only 38 light years distant.

Edited by Fiske, 30 April 2023 - 10:00 PM.

[jrazz]

Once it clears my house I'll look for it... Still early in the year for ViR

[Fiske]

A double star worthy of your mighty 100XL-SD, Jordan. 

Edited by Fiske, 30 April 2023 - 09:10 PM.

[clastro8*]

Thanks for the picture, Fiske.

 

You were facing SE, correct?  There are a couple of other stars shown, I think, when you make a drawing like that do you also review the fov area in an atlas and, so to speak, use that as a guide and prove to yourself seeing the other stars?  Also, what are those squiggly lines you drew there?

 

In the other recent thread about defining bino doubles, one poster referred to PA as it changes over time, just as you mentioned in this instance.  Now I would like to know a bit more about that, in this sense, it would be nice to be able to observe such a change, but I think his point was it can involve many years before it would be observable with amateur equipment.  I can understand that but wonder if binos generally don't prove high enough magnification or technique to make finer measurements in that effect.  Do I understand that correctly?

[Fiske]

Thanks for the picture, Fiske.

 

You were facing SE, correct?  There are a couple of other stars shown, I think, when you make a drawing like that do you also review the fov area in an atlas and, so to speak, use that as a guide and prove to yourself seeing the other stars?  Also, what are those squiggly lines you drew there?

 

In the other recent thread about defining bino doubles, one poster referred to PA as it changes over time, just as you mentioned in this instance.  Now I would like to know a bit more about that, in this sense, it would be nice to be able to observe such a change, but I think his point was it can involve many years before it would be observable with amateur equipment.  I can understand that but wonder if binos generally don't prove high enough magnification or technique to make finer measurements in that effect.  Do I understand that correctly?

Hi, Clastro.

 

What direction I was facing doesn't matter because the telescope view is mirror-reversed (and probably upside down too).  The mount is a CI-700, so one establishes cardinal directions by temporarily turning off tracking to establish west (stars drift west). Then turning tracking back on and using the hand controller to move the field north to establish north.

 

The squiggly lines are the cardinal directions.   E (top left) S (top right) N (bottom left) W (bottom right). That field star at the top right (south) is HD 110381 (8.88 mag). The other two stars have impossibly long gaia numbers. Their magnitudes are 11.64 (top right) and 12.44 (closest to Porrima). 

 

This is a small field of view. I haven't done the math on it, but 0.25 degrees or smaller is my guess.

 

A list of doubles where orbital change can be detected visually is going to be small, and following those is going to be more a game for telescopes than for binoculars (because the separations are going to be quite small and the need for precisely establishing cardinal directions is considerable). 

 

So, no, binoculars are not ideal for observing double star orbits. If one were determined to pursue it with a binocular, the instrument of choice would be a binocular telescope at "higher" magnification. Say 80x. Or if one were a BT hero (like Jordan ) then 100x plus.

[clastro8*]

Thanks, Fiske, just to be sure I understand, the squiggly lines inside the circle are the path westward in the fov you observed looking at the target after turning off the tracking, correct?  And that path once it gets to the perimeter of the circle would designate the W point on the circle.  Then the other cardinal directions would be entered on the circle going counterclockwise.

[jrazz]

Wasn't sure where to post this - either in "what did you see last night" or here....

 

Since it's all doubles I figure here.

19 MPSAS, meh visibility. I took it upon myself to pick out a couple of really tight doubles for the APM 34x80. General rules were UMa, sep: 4"..9", Mag<9.

 

Here's the list of successfully split doubles (along with my notes) showing just how awesome this 34x80 is! 

 

STF1427

10h 22m 00.53s +43° 54' 19.3" P.A. 215.00 sep 9.3 mag 8.18,8.54 Sp F5V dist. 105.04 pc (342.64 l.y.)

Notes: yellow-blue pair

 

STF1459

10h 40m 12.46s +38° 24' 11.4" P.A. 153.00 sep 4.6 mag 8.34,8.85 Sp K4III dist. 2325.58 pc (7586.04 l.y.)

Notes: one white, one yellow very tight

 

STF1258

08h 43m 25.41s +48° 51' 41.9" P.A. 331.00 sep 10.1 mag 7.72,7.87 Sp F0 dist. 143.47 pc (468 l.y.)

Notes: pretty bright!

 

STF1340AB

09h 22m 32.22s +49° 32' 41.4" P.A. 319.00 sep 6.3 mag 7.08,8.99 Sp B9.5V dist. 226.24 pc (737.99 l.y.)

Notes: Could barely see the secondary. Only in averted vision.

 

STF1312

09h 10m 18.19s +52° 23' 05.7" P.A. 147.00 sep 4.7 mag 8.35,8.80 Sp F2V dist. 952.38 pc (3106.66 l.y.)

Notes: Insanely tight but even double

 

STF1346AB (21 Hya)

09h 25m 37.88s +54° 00' 57.5" P.A. 315.00 sep 5.8 mag 7.69,8.59 Sp A2V dist. 196.08 pc (639.61 l.y.)

Notes: really hard to see secondary

 

STF1510

11h 08m 00.06s +52° 49' 17.9" P.A. 327.70 sep 5.6 mag 7.65,9.03 Sp F8V dist. 55.96 pc (182.54 l.y.)

Notes: Primary is yellow and pretty, secondary is white and hard to see.

 

STF1553

11h 36m 35.69s +56° 08' 07.3" P.A. 165.70 sep 6.2 mag 7.73,8.17 Sp G5+K7V dist. 46.99 pc (153.28 l.y.)

Notes: Yellow/Orange pair - really pretty!!

 

STF1600

12h 05m 34.42s +51° 55' 52.2" P.A. 92.00 sep 7.8 mag 7.63,8.28 Sp G8III dist. 369 pc (1203.68 l.y.)

Notes: Clean sharp separation. White/yellow.

 

STF1561AB

11h 38m 44.90s +45° 06' 30.3" P.A. 245.50 sep 8.9 mag 6.53,8.23 Sp G0V dist. 23.25 pc (75.84 l.y.)

Notes: Uneven but relatively wide (shows how narrow all of these were!)

 

Finally an outlier (bit wide for the list but still, nice)

STF1350AB

09h 34m 19.56s +66° 47' 42.3" P.A. 249.00 sep 10.2 mag 8.26,8.31 Sp F4V+F6V dist. 225.73 pc (736.33 l.y.)

Notes: Two sharp points!

 

 

So many many doubles. The APM 34x80 is an amazing instrument and on the Orion Monster pgram an absolute master of tight doubles. Especially on "bright" nights it's really a capable instrument. Makes me wonder how good the good Docter is!

[Fiske]

Outstanding, Jordan! 

 

  

 

Thank you for sharing this excellent report. Planning further adventures in Ursa Major now. 

Edited by Fiske, 02 May 2023 - 08:44 AM.

[Fiske]

Over the last few weeks (during rare breaks in cloudy skies and rain) I have pursued binary star adventures in Leo Minor involving four SHY double stars from a catalog 228 binary systems compiled by professional astronomers Ed Shaya and Rob Olling by using statistical analysis to identify widely spaced binary stars from the Tycho-2 catalog that have a gravitational relationship or are moving through space together.

 

Details (including finder charts) are provided in these two posts on my ExploreTheNightSky blog.

 

A Shy Double Star in the Little Lion

 

Further Adventures with Comoving Stellar Companions

 

One of the binaries is easily viewed with small handheld binoculars -- SHY 212.

 

SHY 212 – HIP 47436 / 47403
09h40m +3520′
6.95/7.18 sep 494.5″ pa 228

 

One is easily seen with a mounted (or Image Stabilized) 10x binocular -- SHY 552.

 

SHY 552 – HIP 50325 / 50327
10h16m +41*17′
7.40/8.78 sep 106.9″ pa 6

 

The other two, SHY 215 and 551, with separations of over 10,000 and 5,000 arc-seconds, are more in the extreme binary sport category. 

 

SHY 215 – HIP 51312 / 52140
10h28m +34*53′
7.90/8.70 10,655.2″ (2*57’35.2″) pa 134*

 

SHY 551 – HIP 47851 / 47399
09h45m +41*09′
AD 9.90/8.82 sep 5,616.3″ (1*33’36.3″) pa 317*

[jrazz]

That's some wide separation!!!

Wow!

 

I'm thinking you need your WX for some of these! (ok, fine, 3° but still impressive!!)

[Fiske]

That's some wide separation!!!

Wow!

 

I'm thinking you need your WX for some of these! (ok, fine, 3° but still impressive!!)

Yeah, I was using the WX Friday night from my yard. 

 

I was able to pick out even the fainter SHY 551 pair with it, but the WX view would be much more glorious from a darker location. I'm hoping I'll get the chance for that in the coming weeks. I also used the Nikon 18x70 Friday night. It is rapidly rising through the ranks of my binocular collection to the inner circle of most loved binoculars. 

Edited by Fiske, 21 May 2023 - 05:09 PM.

[jrazz]

So yesterday was more about trying out my nifty new BT-PGram mount...

 

And my shiny blingy eyepieces...

 

 

However, I was looking at Alcor...

PSF   1Ca,Cb (Alcor Ca/Cb)

13h 25m 13.53s +54° 59' 16.6" P.A. 207.00 sep 1.0 mag 4.01,8.00 Sp A5V dist. 25.06 pc (81.75 l.y.)

 

I noticed clear elongation! At 140X!!! Wow!!! Remember, this is using a 100mm BT! 

The seeing was heavily affected by the smoke but the atmosphere was very stable. I'm hoping the skies clear up a bit and I'll be able to examine this further.

 

I also tried another super-close double:

HU  731 (MY UMa)

11h 51m 57.86s +48° 05' 19.5" P.A. 307.00 sep 1.2 mag 9.81,9.68 Sp K0V dist. 46.1 pc (150.38 l.y.)

 

This was somewhat hard to see because of the smoke but I'm fairly certain I saw elongation along the correct axis. 

 

Humidity and smoke got the better of me after this but I am super super thrilled at this setup. Yes, star hopping is incredibly challenging with an AFOV of 52° and a magnification of 140x but to me that is also half the fun. Can't wait for the summer night and having Cygnus up high!

 

Edit: Fiske, I just realized that we were observing polar opposites of binocular double stars 

Edited by jrazz, 21 May 2023 - 06:10 PM.

[Fiske]

...

 

Edit: Fiske, I just realized that we were observing polar opposites of binocular double stars 

  

 

Not quite polar, but cetainly heading in opposite directions.

 

I enjoy following your sub-2-arc-second adventures, Jordan. As I expect you enjoy following my binocular double star whims and exploits. 

 

Congrats on the TAK eyepieces. I'm glad you've found something that works so well for you. 

[aznuge]

^^ The SHY sky seems intriguing...