622 replies to this topic

[jrazz]

Found another dubious double in the list...

 

ARG 106AB (SAO 32281)

20h 05m 22.55s +58° 07' 21.5" P.A. 178.00 sep 30.0 mag 9.76,10.32 Sp F8

 

I've now tried observing it twice. Even brought out the 100XL but was unable (20.5mpsas sky).

I mean there's certainly a star there but I think the secondary is much fainter than 10.3. 

 

Oof, I'm going to have to drag out the telescope for this one, aren't I?

 

 

Edit: OK, I dragged out the telescope and found the secondary. Needed to go to 170x to see it! I believe it's apparent magnitude is more like 14, not 10!

Edited by jrazz, 23 August 2022 - 12:46 AM.

[Fiske]

Jordan,

 

I noticed that stelledoppie indicates a note for ARG 106, and found this in the WDS Notes file.

 

 

20054+5807 A   866     Aka ARG 106. B is BD+57@2131. Pair correctly identified by Marco Scardia.  Sca2018d

 

So really, ARG 106 and A 866 are the same double star. Sky Safari is indicating that HD 239319 is A 866, but that isn't correct. Here is the corresponding simbad image:

 

 

HD 191609 is annotated to help with orientation in Sky Safari -- it's a brighter nearby star. 

 

Since both A 866 / ARG 106 are the same double star, the data for one of them is incorrect because the A/B magnitudes do not agree. At least that is my guess.

 

I'm looking forward to observing this double now. Thanks for sharing your observation! 

Edited by Fiske, 23 August 2022 - 07:20 AM.

[Fiske]

Oh. And here is another interesting thing. 

 

It seems like the faint star immediately below HD 239319 is S Cygni, which is an M-type pulsating Mira variable with a magnitude range of 9.3 to 16 magnitude. I'm guessing at or near maxium, that would be the "secondary" component to HD239319.  Which is probably around 14th magnitude right now (322.9 day period).

 

Sure enough, recent observations reported on the AAVSO site are listing it at 13.9.

Edited by Fiske, 23 August 2022 - 08:18 AM.

[jrazz]

 

OK that makes way more sense. I was looking there and could not figure out what I was looking at. All the same time there was a wonderful double just by it and I thought to myself "that is a really neat double, too bad it's not the one I'm looking for"

 

I guess I can mark it off the list.

 

 

BTW,

Yesterday was amazing. As I was setting up, I locked on a star and started focusing. I thought it looked neat so I just stared at it and the longer I stared at it the more it seemed odd. I realized then that I was looking at a really close double. Some reverse star hopping and orientation brought up the name:

 

STF2611

19h 58m 51.90s +47° 21' 48.2" P.A. 208.00 sep 5.2 mag 8.47,8.48 Sp K0 dist. 294.99 pc (962.26 l.y.)

 

So yeah, I split a 5.2" double with the 20x65ED! That is certainly my record. I didn't think it was actually possible. Just goes to show how awesome the 20x65 is  

 

I'm hoping we're slowly dropping into the wonderfully clear night of fall. September and October are beautiful here. Can't wait to see what the 34x80 has to offer! (it's on it's way  )

[Fiske]

Here is a simulation of what S Cygni will look like when it is close to its maximum in early December 2022. HD 239319, incorrectly identified as A 866 by Sky Safari, will look like a double star again.  (Hint: Compare this image with the simbad image in post 277 above.)

 

 

This is a fun thing to be aware of. It should be observable either early evenings in the far west in November, or maybe in the early morning in January/February depending on Cygnus's position from your locality.

Edited by Fiske, 23 August 2022 - 02:00 PM.

[jrazz]

That's so cool!!

[Fiske]

It was your discovery, Jordan. 

[Fiske]

Hint: Making a sketch of the FOV now to compare with the view when it is closer to maximum adds to the experience. 

[jrazz]

 

I think it's super cool and it makes lot's of sense. I could definitely see it with the telescope but it was close to the limiting magnitude. I tried calculating what that is and came up to 14 which dovetails nicely with what you found.

 

I don't have the patience for drawing but maybe in this case it would have made more sense.

[Fiske]

Well, if you haven't tried sketching at the eyepiece, it is a lot of fun and not as difficult as it sounds. And looking back at sketches is pleasing. 

[clastro8*]

I enjoyed reading the last few postings.

 

On perhaps a more 'pedestrian' double, I wanted to observe Cygnus Omicron, 30, and 31, which is an a-star plus two companions.  From what I've read, there is a third companion involved which is too close for ordinary binoculars.

 

The stats are mags 3.9,7.0, and 4.8; seps 109" and 337"; PA's 173 and 322.

 

I've looked at it several evenings and double-checked everything but I can only see the primary and the second companion using 15x and 25x.  The companion at mag 7.0, sep 109, and PA 173 eludes me.

 

The only thing I can think of is because the mag at 7.0 is 1/17 the mag of the primary, my equipment/eyesight/Bortle/experience, etc just aren't sensitive enough to pick up something that dim standing near its primary.

 

One reason I say that is, I surprised myself using the 15x seeing the companion with Albireo; it was close but standing right next to the a-star at sep of 35 " and mag 1/4 the brightness (much brighter than 1/17th).

[jrazz]

Thank you and welcome to the kooky world of binocular doubles...

 

7th mag is not too dim. You can probably convince yourself by looking at other 7th magnitude stars and seeing how well you see them. I think the problem might be that it's hiding in the glare of the primary. I know some have had success reducing glare by reducing the aperture of their instruments. If you have a 25x100 try making cardboard masks to reduce the aperture to 70mm. That might be enough.

 

Another culprit might be the stability of your mount. It really needs to be dead steady. Even tiny movements tend to hide the dimmer stars. I make it a point not to be touching the binoculars at all and hover just past the eyepieces. This allows the binocular to be super steady and increases my visual acuity significantly. 

 

Finally, it is surprising how much technique is involved. I have fairly dark skies so it's way easier for me. I always stumble when the moon is out since it's so much harder to pick out stars under "bright" light. Some others here are far more experienced and it shows. Give yourself time and keep on trying. It's really fun when you finally see it!

[Daniellepurple]

I enjoyed reading the last few postings.

 

On perhaps a more 'pedestrian' double, I wanted to observe Cygnus Omicron, 30, and 31, which is an a-star plus two companions.  From what I've read, there is a third companion involved which is too close for ordinary binoculars.

 

The stats are mags 3.9,7.0, and 4.8; seps 109" and 337"; PA's 173 and 322.

 

I've looked at it several evenings and double-checked everything but I can only see the primary and the second companion using 15x and 25x.  The companion at mag 7.0, sep 109, and PA 173 eludes me.

 

The only thing I can think of is because the mag at 7.0 is 1/17 the mag of the primary, my equipment/eyesight/Bortle/experience, etc just aren't sensitive enough to pick up something that dim standing near its primary.

 

One reason I say that is, I surprised myself using the 15x seeing the companion with Albireo; it was close but standing right next to the a-star at sep of 35 " and mag 1/4 the brightness (much brighter than 1/17th).

I was looking at this one last night. My 8x56 could not resolve the mag 7.0 star. I dragged out my trusty 6inch f/8 reflector which easily separated the 3rd component.

I was interested in this as I really enjoy the color contrasting doubles. Cyg omicron is gorgeous in my reflector. Its really nice in the 8 x56 too but I wanted to see all three.

The upshot for me, I really like my 8x56 Celestron binos but I am now convinced that I am need to get a mount and either the 15x70 or 20x80 Oberwerk as I am enjoying the binocular doubles very much.

[clastro8*]

Thank you very kindly for your reply.

 

I have been using a monopod because Cygnus is too high overhead right now to use my tripod.  There is some shake with the monopod but it's been ok for the doubles I've observed recently with comparable separation.

 

Yes, I think the problem is the companion hiding in the glare of the primary star.  I think I proved that for myself last evening by noting the nearby Omicron 2 has a couple of mag 7-type stars around it which I am able to see using averted vision, one such using only 10x binos.   According to my Atlas, one of those stars is on a line between O2 and O1 just outside of O2.  I estimate it to be 1/3 of a degree (1200 arc secs) south of O2 and I can see it pretty well with averted.  A couple of nights ago, I mistakenly thought O2 and its neighbors were the configuration O1 that I was looking for but realized that was incorrect (eventually) and was tempted to make the same mistake last night, as well.

 

But then I realized, hey, that's O2, not O1, but the key is that if I require averted vision to see an object 1200 arc secs distant from a nearby object, what is the likelihood averted vision won't work anymore for an object 109 arc secs distant from its companion, ie, much, much closer?  And the answer must be averted vision won't hack it anymore for something so close, it seems to me.  There ought to be a word or phrase to signify a situation like this if there isn't one already, to signify small separation and glare working together won't permit seeing a primary and companion which could otherwise be observed easily.

 

So, even though I haven't been able to make the observation of this double yet, I'm very happy to have an explanation likely why I haven't. 

[Fiske]

I was a little surprised that difficulty would be encountered resolving the "c" component of STFA 50AC, given the separation of 108.6". Hand held with lower magnification would be problematic. Maybe also observing near the zenith without a p-gram like the Farpoint UBM. It does seem close in this simbad image. This is an example of a double that should have made the Cygni 100 Challenge list but was excluded due to the magnitude difference between the primary and secondary, despite the separation.

 

STFA 50AC

20h13m +46*44'

3.93/6.97 108.6" pa 173*

 

 

I will try observing it with lower magnification instruments and follow up with a report. 

 

Incidentally, the colorful double at the upper left of this image is on the Cygni 100 list.

 

BLL 49

20h19m +47*54'

7.97/8.98 65.4" pa 231*

Edited by Fiske, 24 August 2022 - 12:05 PM.

[clastro8*]

I haven't taken my scope out of the mothballs yet for doubles but I have been tempted to do so.  It's a scope that finds everything for you and then tells you to take a look, so using it never presented the 'where do I find it?' challenges.

 

One thing I've wondered about if a telescope is used with binos, it usually will invert or reverse the image so that especially where one is looking for two stars in a certain PA relationship one vis-a-vis the other, that relationship would be visually different when viewed vs binos.  I'm sure the difference can be gotten used to, but as in the case of O1, I was trying to figure out where the companion is supposed to be and why it isn't there. 

 

And, of course, from time to time unintentionally I can be looking in the wrong place anyway.

 

Update to ask about Fiske's last comment, ie, '... double that should have made the Cygni 100 Challenge list but was excluded due to the magnitude difference between the primary and secondary, despite the separation.'  So you did not exclude it bc of the likely glare situation discussed above?  I did wonder about that.

Edited by clastro8*, 24 August 2022 - 01:10 PM.

[GamesForOne]

...

 

Incidentally, the colorful double at the upper left of this image is on the Cygni 100 list.

 

BLL 49

20h19m +47*54'

7.97/8.98 65.4" pa 231*

Also, the red component is known as the carbon star U Cygni and is a variable that oscillates between about 6th and 12th magnitude. It is likely just a visual alignment and not a true double system. (?)

 

---

Michael Mc

[Whirlaway]

Wow! That is an impressive optics performance, Nuge. (As JG is want to say.) Well done. 

 

Thank you for sharing your observation.

 

I suspect my eyes just aren't sharp enough to see that level of detail at 10x. I'll try with the APM 12x50 and take a run at it with a few 10x50 instruments, including the OB 10x50 Ultra, which seems to have something a bit extra in the sharpness department at the center of the FOV.

 

When observing the moon with a 100mm BT, are you doing anything to reduce the brightness? Viewing the moon near full with a 100mm BT, I worry that it is so bright it might not be good for my vision. I can't use neutral density filters with my beloved Pentax WX eyepieces in the 100XL -- they won't come to focus with the added extension. One solution would be a filter that threads into the bottom of the eyepiece, which is possible but I haven't found any designs like that, and removing them would be a pain, probably requiring a special tool. I guess the obvious alternative would be to mask the aperture.

 

What eyepieces were you trying out?

 

Fiske

You can try gel type neutral density filters in front of the objectives. That may help. Maybe tape them on or devise a holder.

 

https://www.adorama....nfo=gel filters

[jrazz]

Decided to go after really tough stars tonight but at 80x (BT-100XL + Pentax 7mm EPs)

 

First I just checked out the Dumbbell Nebula which was incredible in this magnification. Super big and bright. I've actually never observed M27 by myself and was really surprised at how big and bright it actually is.

 

From there I looked at:

STF2382AB (Eps1 Lyr) - 18h 44m 20.34s +39° 40' 12.4" P.A. 344.20 sep 2.3 mag 5.15,6.10 Sp A4V+F1V dist. 49.78 pc (162.38 l.y.)

and

STF2383CD - 18h 44m 22.78s +39° 36' 45.8" P.A. 73.90 sep 2.4 mag 5.25,5.38 Sp A8Vn+F0Vn dist. 47.69 pc (155.56 l.y.)

 

Honestly just because I could. At 80x each of these show a clear separation. They're pretty but kinda boring and easy to find.

 

Then came the challenges:

STF2104AB - 16h 48m 41.48s +35° 55' 19.3" P.A. 18.00 sep 5.7 mag 7.49,8.78 Sp F2 dist. 172.71 pc (563.38 l.y.)

This one wasn't hard to find. I've been spending a lot of time in Cygnus thanks to Fiske and Hercules seems totally devoid of stars... Almost empty. Just start at M13 and go up and left. Again, at 80x this isn't a challenge but is not as obvious as Eps Lyr.

 

STF2097AB - 16h 44m 47.22s +35° 44' 16.7" P.A. 80.00 sep 1.9 mag 9.37,9.55 Sp G5 dist. 125 pc (407.75 l.y.)

So yeah, even at 80x this one is tough. The double is fairly even but dim. Took a while to really see the separation between the two. Again, not hard to find but really difficult to split.

 

Finally:

STF2101AB - 16h 45m 48.14s +35° 37' 50.5" P.A. 47.00 sep 4.1 mag 7.51,9.39 Sp F6V dist. 58.82 pc (191.87 l.y.)

Maybe a bit more separation but the magnitude difference made it even harder to see. One of the things though is that both 2097 and 2101 are visible in the same view at the same time so if you find  one, you've found the other.

 

So that was my short night tonight. I need to go around Aquila for a bit before returning to Cygnus and wrapping up the 100 challenge. That area is DOPE. Should be a treat with the 34x80.

Beyond that sometimes it's fun to bring out the big guns and go after what is realistically telescope targets. I did think that the telescope would have split some of these easier but there's something so nice about the 100XL that makes it much more compelling to me.

 

[Fiske]

I was a little surprised that difficulty would be encountered resolving the "c" component of STFA 50AC, given the separation of 108.6". Hand held with lower magnification would be problematic. Maybe also observing near the zenith without a p-gram like the Farpoint UBM. It does seem close in this simbad image. This is an example of a double that should have made the Cygni 100 Challenge list but was excluded due to the magnitude difference between the primary and secondary, despite the separation.

 

STFA 50AC

20h13m +46*44'

3.93/6.97 108.6" pa 173*

 

I will try observing it with lower magnification instruments and follow up with a report. 

I have made multiple observations of Omicron1 and its companions over a few evenings, both from a darker Bortle 5 location and from my Bortle 7 driveway.

 

From the darker site, I found that both components of STFA 50AC could be resolved with handheld 7x and 8x binoculars, though not a pleasing observation compared with a mounted instrument. From my Bortle 7 driveway (18.35-45 mpsas), it was more difficult to resolve the 7th magnitude "C" component with hand held 7x and 8x binoculars, but it could still be glimpsed. Mounted on my Farpoint UBM, all three stars were easily seen with the following binoculars: Nikon 8x30 EII, Nikon 8x42 Monarch HG, Maven b.2 7x45, Nikon 7x50 SP, Kowa 6.5x32, and even a Kowa 6x30. Also easily seen with a Canon 10x42L image stabilized binocular and with various non IS 10x and 12x instruments, though nowhere near as pleasing to observe compared with UBM mounted binoculars or the Canon 10x42L.

Edited by Fiske, 02 September 2022 - 08:28 AM.

[clastro8*]

Hi, Fiske, I enjoyed reading your report above.

 

I still haven't been able to see the dimmer companion star for O1 but I am not too surprised about this because I can see mag 7 or so stars between O2 and O1 as well as south of 01 using averted vision; this seems to tell me something which I think probably is glare from the primary star gets in the way when the separation between the stars is 100 arc secs or so.  Also, using 7x and averted vision, I can't see those other mag 7 stars, so your being able to see the double with 6x tells me Bortle/equipment/vision/experience/ etc just means I can't replicate your observation, unfortunately.

 

One of my attempts was in the wee hours on a very clear night using my tripod.  I didn't have better results but did figure out how to use the tripod with no shake for an object high overhead for the first time. 

 

I've had a similar problem, I think, with Zeta Gemini where the sep is about the same but the mag difference is even greater.

[Fiske]

Honestly, Clastro. I'm puzzled by this. What binocular are you using? I mean, I was able to resolve it with a mounted 7x45, for goodness sakes. It should be relatively easy to observe...

 

 

Even a 6x30, come to that. Mounted, anyway. From a Bortle 7 sky.

 

This is what that looks like, BTW. The Kowa 6x30 on the OB 5000 tripod with the Farpoint UBM.

 

 

I have to admit, I have totally fallen in love with the Farpoint UBM since putting it on the OB 5000 mount. It can accommodate binoculars from the OB 25x100 (10 pounds) to the Kowa 6x30 (17 ounces).  It is necessary to remove one of the 2.5 kg weights to balance the lightest binoculars like the Kowa 6x30, 6.5x32, or the Nikon 8x30 EII. But that only takes a moment. A Neewer quick release adapter (a Manfrotto 500 series knockoff) has been added to the UBM, making it a cinch to swap binoculars. 

Edited by Fiske, 04 September 2022 - 05:57 PM.

[Fiske]

Here is the 25x100 on the UBM. Note: second 2.5 kg weight reinstalled.

 

[jrazz]

Bahh..

 

We all know the best binocular is the 20x65ED!!!  

 

 

I've just come in after another pass at the Cygnus 100 challenge. I only have 14 doubles left! (not counting duplicates and IR stars)

All of them were doable with the 20x65 though to be fair, some are tough to resolve. Not sure all of the 20x binoculars or every sky conditions are good for 7" doubles. I could easily split HJ 1526 (20h 30m 40.68s +35° 20' 53.2" P.A. 149.00 sep 8.8 mag 9.00,9.26 Sp A2) tonight. It was "sparkly" out there! Not terribly dark since the moon is out but the sky is very very clear and visibility/transparency are amazing right now.

[Fiske]

Yeah, I've got one of those too. 

 

I also observed HJ 1526 this evening, and was wondering how you did with it. Good job resolving it! 

 

HJ 1526

20h30m +35*20'

9.00/9.26 8.8" 149*

 

Could not resolve this with the 70XL+20XWs (19.5x). It might be doable with this combination from a darker site. (18.28 mpsas this evening.) Or from here with the 14XWs (27.85x). I was able to resolve it with the 25x100 (even though Jordan thinks the 20x65ED eats its lunch ). Two golden stars nestled together but cleanly separated. Close to the limit for the 25x100 under these skies. 

 

Another one of my faves this evening is STF 2691. 

 

STF 2691

20h29m +38*07'

8.14/8.45 16.3" pa 32*

 

A neat close pair of warm whites stars immediately southeast of one of the three triangle asterism stars I use to locate M 29. I have observed this starfield countless times and never noticed this double. And yet easily and immediately seen once one seeks it out. Fun!

 

And here is a nice challenge for 10x binoculars -- this is the kind of thing you recall when staying up insanely late, poking about in Triangulum, and thinking wasn't there a nice DS nearby? Oh, yeah. There it is. 59 Andromedae. Hey, I bet this could be resolved with the Maven 10x56. Sure enough. How would the Swaro 10x56 SLC compare. (Right there with the Maven, actually.) 

 

STF 222 / 59 Andromedae

02h10m +39*02'

6.05/6.71 16.6" pa 36*

 

 

In this image 25x100 was serving up a gorgeous view of the Double Cluster in Perseus, while the 70XL was offering a fine view of the open cluster NGC 752 in Andromeda. The 20x65ED is languishing in the background, top shelf of the rolling light shield unit behind the OB PM2ish p-gram, next to where the 25x100 had been resting before going for a ride on the Farpoint UBM. 

Edited by Fiske, 05 September 2022 - 04:08 AM.