601 replies to this topic

[Fiske]

I came across another Cygni 100 Challenge marauder last night. 

 

HJ 1505

20h21m +43*35'

7.85/8.54 16.7" pa 111*

 

I could not resolve it with the Kowa at 21x (easily within the instrument's capabilities at that magnification). I doubled checked the chart and also cross-referenced simbad and was absolutely looking at the correct star. Van Jan in the Double Star forum came to my aid on this one. 

 

Here is the WDS entry for the double star:

 

20212+4335HJ 1505      1828 2015   15 110 111  12.5  16.7  7.85  8.54 B9.5V     +005+003 +001-004 +43 3576      202114.01+433521.2

 

The B9.5V entry in the notes column indicates that the B component visual magnitude is 9.5 not 8.54. The Sky Catalog 2000 actually lists it at 10.1. I am planning to revisit with more magnification, or aperture, or from a darker site to confirm. An interesting note is that Sky Safari draws star symbols based on stellar data from various sources, including the WDS, and is not accounting for the visual magnitude listed in the notes column, so the double star's representation in SS is itself misleading.

I have been advised that B9.5V is the spectral class of the primary star. 

[clastro8*]

Hi, Fiske, a point of information regarding the discussion on page 12 stemming from my inability to observe the 2nd companion to Omicron Cygni vs your success observing it with various binos including with small magnifications, I continue attempting to observe it at various times without any success.

 

I still think it is a matter of the primary being much brighter for me than the elusive secondary in magnitude.  To get a better idea about that, I found Phi Cass whose criteria are RA 1 20, Dec 58 14, mags 7.0/5.1, sep 133, and PA 235.  The sep is in the ballpark of O1 but the difference in mag of O1 is much brighter vs Phi Cass, ie the mag difference in the O1 is 17x vs 6x in Phi Cass.

 

And happy to say, I was able to observe the double in Phi 3 out of 4 evenings, best mostly using averted vision but not entirely requiring it using 20x binos.  I could not observe the double with 10x.  My point would be, if I have to use averted vision for a sep of around 100 arc secs and mag difference of 6x, it is reasonable to assume averted vision may not work anymore for seps of 100 arc secs if the mag difference grows to 17x.

 

So I was happy to observe the latter and last evening after the one success and the other another time of failure, I found myself humming an old tune and  paraphrasing the lyrics with 'if you can't observe the one you want to love, love the one you can observe.'

Edited by clastro8*, 18 September 2022 - 05:25 PM.

[MT4]

Got a lot of quality instruments and a brand-new copy of the wonderful “Discovering Double Stars” book for light-polluted skies but what to do while still in the middle of the typhoon season?  

 

Does using the book to find double stars in the Stellarium app running on my 28” iMac count as doing some backyard astronomy under the circumstances?  

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[Fiske]

I wrapped up the Cygni 100 Challenge doubles list Sunday evening (18 September 2022), though I still plan to pinpoint the precise locations of CAN 20 and 40, which turned out not to be observable because their listed magnitudes are in infrared not visible light. The idea of the challenge list was to demonstrate the vast array of double stars accessible to binoculars, which it surely accomplished. 100 double stars in a single constellation.  In fact many, many doubles observable in Cygnus with even moderate size binoculars were not included in the challenge. All told, StelleDoppie lists over 10,000 double stars in Cygnus.  Of course, many of these are too faint or too close to be observed with telescopes, let alone binoculars, but even limiting the list to what is likely to be observable with say a 100mm BT, the number is still approachng 2,000.

 

I hadn't appreciated how absorbing the project would be, or the wealth of information that can be found about stars in a single constellation. I was constantly noticing additional doubles that just missed the cutoff because they had slightly lesser magnitudes or had a slightly larger difference in magnitudes than the cutoff limit of 2.0x.

 

Here for example is a double I observed Sunday evening, while working along a line of doubles toward the northern end of Cygnus -- slightly fainter than the 9.5 magnitude cutoff.

 

ES 2692
20h18m +52*12'
9.55/9.61 24.5" pa 85*

 

Kowa+32x / OB 82XL+32x / 20x80 Deluxe III

An evenly matched, cozy pair, both stars white, in a beautiful asterism nicely framed in the 82XL+14XW (32x) field. In the same field with ES 800. The ds is fainter than the surrounding asterism but still distinctive, somehow. Oddly, it looks brighter in the 20x80 view compared with either BT, I don't know how. It's a beautiful starfield viewed with the 20x80, and ES 2692 is a fabu 20x80 double. Viewed with the Kowa, the components take on a ruddy cast.

 

Edited by Fiske, 20 September 2022 - 09:21 PM.

[jrazz]

 

I hadn't appreciated how absorbing the project would be, or the wealth of information that can be found about stars in a single constellation. I was constantly noticing additional doubles that just missed the cutoff because they had slightly lesser magnitudes or had a slightly larger difference in magnitudes than the cutoff limit of 2.0x.

 

 

Oh boy, you can say that again!!

[Fiske]

Here is a fun development regarding HJ 1505, mentioned in post 324 above -- a reply from Rachel Matson, an astronomer at the US Navy Observatory, on September 20, 2022 to an email I sent to her regarding this double star.

 

Thanks for bringing the incorrect magnitude of HJ 1505 to my attention. It looks like recent observations of the double have measured the secondary to be ~11th magnitude, which is also confirmed by Simbad. I will update this in the WDS and it should be reflected online in the coming weeks.

Multiple Cloudy Nights participants contributed observations and information about HJ 1505, including Jordan in this forum and double star experts from the Cloudy Nights Double Star forum. 

Edited by Fiske, 22 September 2022 - 12:11 PM.

[Fiske]

I followed up on CAN 20 and CAN 40 last night, two double stars that were included in the Cygni 100 Challenge list based on magnitudes that turned out to be infrared, so not visually observable. (See post 267 above, and following posts, for more details.)

 

Anyway, it sounded like fun to track them down, or at least pinpoint their approximate location, so last night I did. 

 

Here are the details for CAN 20, plus the rather critical notes detail from the stelledoppie listing, which I cleverly overlooked. 

 

CAN 20AC

20h34m +40*51'

6.90/8.60 13.8" pa 330

Notes: K (K-band or other infrared magnitudes)

 

I couldn't say how long I spent studying this starfield -- time has a tendency to stand still for me in such contexts. (Guessing 45 minutes to an hour between CAN 20 and 40 together.) Here is an annotated simbad chart of the starfield.

 

 

I worked on CAN 40 before turning to CAN 20, and realized that the 20x80 Deluxe just didn't go deep enough to accurately pinpoint the CAN 40 position. No hope of seeing it visually from my driveway (visual magnitude 13.71), except perhaps with the 22-inch dob, which I still haven't gotten back in operation. Though chasing down something like this might be a motivator to get me moving on it. Anyway, I swapped the Oberwerk 20x80 out for the 25x100 (Farpoint UBM on the OB 5000 tripod), which did go deep enough so I could see guide stars to find the location of CAN 40. More on that later.

 

I navigated to the CAN 20 position from Gamma Cygni (aka Sadr) the center star of the Cygnus "cross" asterism, enjoying quite a pleasing view of the open cluster NGC 6910 with the 25x100 while finding my way. The arc of stars is a significant marker to orient around. No hint of the nebulosity can be seen in Bortle 7 skies, needless to say. The line of faint stars pointing north in the image leads to the position of CAN 40. 

 

HJ 609 is a legitimate Cygni 100 Challenge double, which I observed Monday 12 September 2022 from my driveway.

 

HJ 609

20h33m +40*27'

8.84/9.34 26.7" pa 320*

 

Observed with Oberwerk 20x80 Deluxe III. A fun DS for the 20x80 under these sky conditions. Precise position must be known, but then not hard to see. Quite close but fully resolved. Both stars white. A bit challenging to hold steadily in direct vision but can be done with some effort. Easier in averted. Should be easier from a darker site.

 

The sky conditions that evening were not great -- 17.34-42 mpsas. In fact I ended my observing session after recording one more observation because the waning gibbous moon (92% full) made the sky so bright it wasn't worth the effort. But last night the moon wasn't a factor at all, and I recorded a sky quality measure of 18.20 mpsas, which is quite good for my location. Plus using the 25x100 made HJ 609 easy to view and striking. I regret not comparing 20x80 and 25x100 observations of it now.  There is always something more to see...

 

HJ 609 is in a line of faint stars leading north to the position of CAN 40, incidentally.

 

AG 409 did not make the Cygni 100 list because the secondary is fainter than the 9.5 magnitude cutoff. It was a delightful find last night, making the CAN 20 effort more than worthwhile (though that search on its own was enjoyable enough).

 

AG 409

20h33m +40*34'

9.40/9.92 9.8" pa 266*

 

I can just resolve this double with the 25x100. Both stars bright white. It is not far from the position for CAN 20. Wow!

 

To pinpoint the location of CAN 20, I worked from a quadrilateral of four stars, the brighter two forming a pointer, plus a second set of two stars making an intersecting line. The faintest of the stars in the quadrilateral grouping is 10.69 magnitude TYC 3157-1184-1. 

 

After all of that effort, I could actually glimpse the CAN 20 primary in averted vision (TYC 3157-0581-1, 11.16 magnitude), but it was near the limit for the 25x100 from my driveway on a good night.

 

For scale, here is a Sky Safari chart of the CAN 20 / 40 starfield .The FOV ring represents the 2.4 degree field of the Oberwerk 25x100 Deluxe binocular. CAN 20 is annotated as TYC 3157-0581-1. CAN 40 as GAIA 2067836.... HJ 609 is annotated as SAO 49778. 

 

 

One thing about making observations like this is that a mounted binocular is a must. There would have been no possible way to resolve any of these doubles or even see the field stars used to triangulate the position of CAN 20 otherwise. But even beyond that, detailed study of a starfield in this fashion requires an instrument that remains in position while consulting charts, working with Sky Safari, and writing notes. Another factor is that the more one researches and learns about a given starfield, the more one appreciates what is seen. In fact, the more one literally sees. This is the secret behind the success of Burnham's Celestial Handbook, and why it remains a favorite among amateur astronomers nearly six decades after its publication when some not insignificant percentage of the science it documents has been superseded by more recent knowledge. 

 

I'll save my observation of CAN 40 for a later post. 

 

Thank you for reading my report. 

Edited by Fiske, 26 September 2022 - 05:21 PM.

[duck2k]

Got a lot of quality instruments and a brand-new copy of the wonderful “Discovering Double Stars” book for light-polluted skies but what to do while still in the middle of the typhoon season?  

 

Does using the book to find double stars in the Stellarium app running on my 28” iMac count as doing some backyard astronomy under the circumstances?  

I just ordered a copy as well.

[Fiske]

Good for you, Duck! 

 

I'm looking forward to hearing about your double star adventures. 

[duck2k]

I got it. Now to wait for a good sky.

 

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[clastro8*]

I'd like to read a little bit more about the book mentioned above.  Is it mostly for telescope observers and large magnification bino observers, say, using 30 x and above?

 

Can you provide an example or two of a doubles target suitable for light-polluted skies? If we go way out such as in the Post 329 above and further, the doubles appear to be all over the fov.  At some distance it would seem there will be more doubles (at least the optical kind) than single objects, so it could be challenging  simply to find a single target shining alone amidst all the doubles 'action' out there.

[Pjmjrastro]

Got a lot of quality instruments and a brand-new copy of the wonderful “Discovering Double Stars” book for light-polluted skies but what to do while still in the middle of the typhoon season?  

 

Does using the book to find double stars in the Stellarium app running on my 28” iMac count as doing some backyard astronomy under the circumstances?  

This book is just what I need! Amazon has it, but not the spiral bound version. 
 

[clastro8*]

Hi, Fiske and jrazz, thanks for your comments and suggestions on Cygnus Omicron, 30, and 31from page 12 of this thread.  It is a bit further along west these days enough to use my tripod without too much neck strain and I am most happy to say I have observed the elusive companion a few times now.  I could not see it for certain using 15 x but with 25 x it just barely but definitely comes into view.   Often I must use averted vision, at least to begin with, but then there it is, so pleasing to see.

 

Now I realize the monopod simply wouldn't work for me on this one and the tripod (no touching allowed!) just makes all the difference.   

[jrazz]

Hi, Fiske and jrazz, thanks for your comments and suggestions on Cygnus Omicron, 30, and 31from page 12 of this thread.  It is a bit further along west these days enough to use my tripod without too much neck strain and I am most happy to say I have observed the elusive companion a few times now.  I could not see it for certain using 15 x but with 25 x it just barely but definitely comes into view.   Often I must use averted vision, at least to begin with, but then there it is, so pleasing to see.

 

Now I realize the monopod simply wouldn't work for me on this one and the tripod (no touching allowed!) just makes all the difference.   

Absolutely! It's such a good technique. I find that I see so much better overall.

[Fiske]

Congratulations, clastro. Well done! 

[Fiske]

Here are several binocular double star adventures for the daring (mount not optional ).

 

This topic began with an observation of 41 Draconis, carried over from a previous topic more specifically devoted to that star. The past three evenings I have been roaming the star fields of Cepheus with a considerable assortment of Team 10x, 12x, and 15x binoculars, and made a few side trips as the fancy caught me, which included a trip into Draco to revisit this binocular double star favorite.

 

STF 2308 / 41 Draconis
18h00m +80*00'
5.70/6.0 18.77" pa 231.8*

 

Emboldened by my success resolving 41 Dra with every 10x binocular I tried, last night (Friday 14 October 2022) I decided to stoop even lower with a Team 7x standout, my prized Maven b.2 7x45. And what to my wondering eyes should appear but two beautiful stars separated by a hair. That might be as low as these sexagenarian eyes can go with this star. Not a poor showing though. 

 

I am working on a Little Known Star Fields post for some fun discoveries in Cepheus (from last night), but in the process of exploring those with the Oberwerk 70XL, I swapped in Pentax 10mm XW eyepieces (39x / 1.79* fov) and went to focus on Alfirk, one of the bright Cepheus asterism stars, and was startled to find myself observing a gorgeous binocular double.

 

STF 2806 / Alfirk
21h28m +70*34'
3.17/8.63 13.5" pa 251*

 

Brilliant white primary with a tiny steel blue pin point companion. Wonderful! Sharp and beautifully resolved.

 

Alfirk seemed a likely member of the Astronomical League Double Star program (for good reason ), and I found my original observation of it from February 3, 2002 in my ALDS notebook. (And this is where we come to the second adventure.)

 

 

I noticed a comment from 22 years ago that Alfirk is easily resolved with a 10x50 binocular (a Nikon Lookout IV, which was not(!) a premium instrument) and beautiful with the 20x80 Orion Megaview. I'm frankly having a hard time crediting the 10x50 observation, though it was from a darker site and I had just observed the double with a C11 and sketched it so I would have known precisely where to look. Needless to say, I plan to revisit it with a few members of Team 10x. Any takers? 

 

 

[jrazz]

Been frequenting the forum less lately. The combination of a very demanding new role and cold weather makes me less interested in sitting outside and looking up. No more!

Logged in to see Too much equipment discussion here. Let's see what the equipment can do!

 

I propose another doubles challenge. This time it's not set up for the inexpensive equipment. You will need around 80x for some of these though a majority should be doable with my APM 34x80 and patience. A 70mm BT might be able to complete everything under great sky but I think you really need a 100mm BT or better and even that's not a guarantee.

 

It is a challenge after all, right?

 

I present you with the Cassiopeia Caper (as in dance)  

 

Here is a link to the Stelle Doppie search. It's 35 doubles in a relatively small area.  

 

 

And yes, a 10" dob would probably be a better tool for many of these. That's not the point. I can plug it into my computer and split all of them in a night. I find that having a list like this helps me explore the constellation and see many other things that jut look better in binoculars. If all you're after is to split the doubles then by all means, fire up that GOTO scope and blast through them. I want to try and observe them all with my 100XL (which is still, a pretty tough challenge)

Edited by jrazz, 15 October 2022 - 02:42 PM.

[jrazz]

Oh my... great minds....

[Fiske]

Logged in to see Too much equipment discussion here. Let's see what the equipment can do!

  

[Fiske]

Oh my... great minds....

  

 

I've been going nuts in Cepheus the last three nights. I would take days (literally) to write posts about all of it. 

[jrazz]

I was on the fence about adding Cep to this list but Cas right now is so nice and has so many interesting sights I decided to focus on it.

[jrazz]

Besides, this list includes STT 1.

Come on, that's just awesome

[Fiske]

 

My front porch, quick session observatory. (Though quick 15-minute observing sessions morph into 90+ minute observing sessions with considerable regularity. ) I'm thinking about extending the front porch by incorporating an extension into the wide steps leading to the porch, and also adding supports to quickly deploy light shields. APM 20x80 ED MS currently seated on the OB 4000 throne. 

 

A bevy of Team 10x, 12x, an 15x heroes from the Wednesday evening session. Note World's Largest 10x50 binocular (aka Big Jon) center back. 

 

Edited by Fiske, 15 October 2022 - 02:37 PM.

[Fiske]

I propose another doubles challenge. This time it's not set up for the inexpensive equipment. You will need around 80x for some of these though a majority should be doable with my APM 34x80 and patience. A 70mm BT might be able to complete everything under great sky but I think you really need a 100mm BT or better and even that's not a guarantee.

I might have a binocular telescope capable of resolving a few of the Cassiopeia (nonpareil) Caper doubles. 

 

 

But how about firing up an iOptron AZ Pro binocular mount for the challenge?

 

 

Not in house yet, but a likely arrival in the not distant future.  One plan for which is using the GoTo functionality to avoid eyepiece swaps after locating the object with wider field eyepieces. But how accurate will it be with a 130x, 0.54* fov? Also using paddle controls instead of repositioning the mount by hand seems like a possibility for smoother panning with less vibration and damping time.

Edited by Fiske, 15 October 2022 - 03:24 PM.

[jrazz]

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But how about firing up an iOptron AZ Pro binocular mount for the challenge?

 

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I'll allow it?

The list is tough. Very tough. My preference is to star hop because, as I've said, that allows me to know the constellation intimately. Doing this at 80x,112x or even 140x is very very demanding. You need the most stable mount you can get and if that happens to be a GOTO then so be it!

 

I'll try to get as many as I can ZPB™ with the APM 34x80 though that might be way too undersized for the task.