601 replies to this topic

[jrazz]

My neck of the woods becomes very cold and unfun in the winter. There usually is also a freezing layer along with some really strong winds which tank seeing. This means I usually miss out on the winter constellations which sucks because I love Orion. Orion is a fantastic constellation right next to the winter milky way with a ton of interesting things and cruising through it with a "wide" binocular (remember I usually hop with a FOV of 2° or less) shows a lot of interesting stuff to look at.

 

 

So my recent acquisition of the Canon 15x50IS (CIS) made me realize that I don't have to stay content with big and blobby views. I love the 10x simplicity of plain binoculars but the sharpness of the CIS made me realize that tight doubles are eminently doable now even in winter!

 

So I set myself a challenge of 50 Doubles that are 8" to 25" in separation and less than magnitude 9. This seems easy for a mounted 34x80 but a real challenge for a 15x binocular (especially hand held). 

 

Of course it needs a name and that name is the Orion 50 (this is because I have no imagination).

 

You can find the list in this link: Orion 50 Challenge

 

The neat things is that while looking for doubles you see so much other stuff that it makes the whole hunt just that much more fun.

 

For example: 

STF 817 (HD 39758)

05h 54m 51.96s +07° 01' 53.8" P.A. 73.00 sep 18.6 mag 8.68,8.93 Sp A5+K

 

This unassuming little yellow double sits right next to Betelgeuse and looks super pretty. We usually look right at the BRG (Big Red Giant) and miss this wonderful interloper. Love it!

 

 

BTW, for those of you with BTs and 34x80's I created a different kind of challenge. The less easy kind. I call it the Orion 50 test

Have fun!

 

 

 

Edit: Yes, I realize that together they are the "Orion 100" but I thought separating them makes for an easier time for those who don't want to go with the super close kind. Some of those are TOUGH!

Edited by jrazz, 24 February 2024 - 07:45 PM.

[Fiske]

A wonderful post, Jordan! 

 

  

 

Thank you for sharing these lists. 

[Fiske]

I observed a few doubles in Orion this evening, following up on Jordan's post. I observed with the Oberwerk 20x70 EDU, but then brought out the AT80ED support telescope for a quick peek at a more challenging double.

 

STF 688

7.52/7.55 sep 10.5" pa 95.4*

 

A pair of evenly matched, yellowish stars nestled together in a delicate but pleasing field. Fully resolved with the 20x70. A splendid 20x binocular double.

 

STF 692

7.64/8.57 sep 34.89" pa 4.3*

 

Yellow primary with a faint white companion at a comfortable distance in a brilliant field including Rigel, Tau, and e Orionis. 

 

STF 701

6.13/8.09 sep 6.17" pa 138.3*

 

I can detect the secondary in contact with the primary with the 20x70, but can't hold it steadily, just glimpsing it from time to time. But beautifully resolved with the AT80ED support telescope at 56x (Baader Hyperion zoom at 10mm). Bright white primary with a faint sand-colored companion hovering by its side. A pleasing support telescope observation.

 

STF 817

8.68/8.93 sep 18.6" pa 73*

 

A modest but lovely double just south of the fiery orange Betelgeuse. Both stars yellow, evenly matched, close but not tight, easily viewed with the 20x70 EDU. A gorgeous star field.

 

 

Edited by Fiske, 25 February 2024 - 11:25 PM.

[jrazz]

I decided to tackle the test with my BT-100XL/SD and the TPL 9mm eyepieces (63x). I've become convinced that these are the ultimate eyepieces for the BT-100. Once you drop below the magical 9mm size the stars are less pinpoint. The 6mm is still good but the 9mm is simply sharp and clear. I also think the 9mm are simply the best focal length of the range. 

 

So. I started outside the list with a nice warm-up.

STF 668 A,BC (Rigel)

05h 14m 32.27s -08° 12' 05.9" P.A. 204.00 sep 9.4 mag 0.30,6.80 Sp B8Iae: dist. 264.55 pc (862.96 l.y.)

 

Did I say the seeing was craptacular? It is. Windy, swimmy, shimmery view. Add to that the 10-15mph winds pushed the BT around.

Still, I managed to see "B" just ok. Speaks to the quality of the BT/TPL combo.

 

Next up is

STF 762 AB,C (Sig Ori)

05h 38m 44.77s -02° 36' 00.2" P.A. 239.00 sep 11.4 mag 3.76,8.79 Sp +B0.5V dist. 328.95 pc (1073.03 l.y.)

Gee, keeping to the script are we? Nevermind. σ Orion is a FANTASTIC system, especially at higher magnifications. Big blue stars sploched about. Just really wonderful. Even at 15x they are still very pretty (First saw them in the CIS) but at 63x the system is marvelous!

 

I then started getting serious and by serious I mean TOUGH doubles. This is a pretty tough test.

STF 816 (HD 39773)

05h 54m 55.46s +05° 51' 38.8" P.A. 287.00 sep 4.0 mag 6.90,9.27 Sp B9 dist. 239.23 pc (780.37 l.y.)

Yeah, 4" of separation and 3 mag difference. Very rewarding double.

 

STF 738 AB (Meissa)

05h 35m 08.28s +09° 56' 03.0" P.A. 43.00 sep 4.1 mag 3.51,5.45 Sp O8III+B0V dist. 336.7 pc (1098.32 l.y.)

Easy to find, hard to split. Easier than STF 816 but still, fairly challenging but very beautiful especially being smack dab in the middle of Collinder 69 (nice).

 

STF 763 AB (HD 37478)

05h 39m 17.19s +10° 15' 35.5" P.A. 318.00 sep 6.3 mag 8.89,9.48 Sp F8 dist. 61.8 pc (201.59 l.y.)

This one was nice. Though dim, it's nicely separated and even. I liked it.

 

STF 750 (HD 37040)

05h 35m 31.07s -04° 21' 50.6" P.A. 60.00 sep 4.2 mag 6.43,8.39 Sp B2.5IV dist. 361.01 pc (1177.61 l.y.)

Not done with the uneven doubles. This one was also hard to see in the soup but after a bit it popped out. 

 

STF 754 (NSV2433)

05h 36m 35.69s -06° 03' 53.1" P.A. 288.00 sep 5.3 mag 5.71,9.24 Sp B1V dist. 471.7 pc (1538.69 l.y.)

OOF, yeah. This one was HARD. Nice separation but holy moly was it tough to see the secondary. Maybe having a spread of 4 as a max was a bad idea...? Naaah.

 

STF 667 (HD 34121)

05h 14m 41.31s -07° 04' 18.1" P.A. 315.00 sep 4.2 mag 7.15,8.78 Sp K2 dist. 297.62 pc (970.84 l.y.)

OK, this one is special. The secondary is RED. Visibly so. I thought I was looking at a red giant or a dwarf and indeed this is either a K2 or K3III giant. So yeah, this is a very colorful and interesting double to look at. Super unique and not too far away at around 300 parsecs. I loved the change from the run-of-the-mill white main sequence stars. Go look at it. It's not a carbon star but I think it's even prettier!

 

Last one I managed to see before the cold drove me inside:

STF 701 (HD 35281)

05h 23m 18.50s -08° 24' 55.9" P.A. 138.00 sep 6.2 mag 6.13,8.09 Sp B8III dist. 122.7 pc (400.25 l.y.)

This is a blue-white pair though I would say more white-yellow. Fine. Class B means blue but the secondary definitely looked yellow. 

 

 

So yeah, a tough test for sure but Orion is proving out to be a real treasure trove of things. Still have many many doubles to go. Keep you posted!

[jrazz]

And I KNEW you'd like STF 817

[Dale Smith]

I continue to be very inspired by this thread. I've decided I really need to regularly do binocular double star observing this year. I did some last year, perhaps a dozen different doubles, mostly in summer. Like Fiske has noted, it's well suited for the Bortle 6/7 skies I have here. I have the Cambridge Double Stars, Sissy Haas's Double Star book, Agne's Clarke's Discovering Double Stars, and the Anthology of Visual Double Stars, along with SkySafari for my iPad. 

 

Trying to decide if I want to start with "easy separation" doubles at 10x, and then view those "targets" at 20x in my Pentax 20x60s and at 32x in my BT-82XL. Then, as I continue, start going for more challenging binocular doubles. I have an AT72edii support telescope to aid me as well.

 

I've already read a lot of great advice, but am always happy to receive more, so please advise away 

[jrazz]

One of the great sources is Stelle Doppie. As we've seen in the past it's not 100% accurate but darn near so.

 

Best part of all, you can go to advanced search and generate a list of doubles that meet a criteria. I usually pick the constellation, a separation range, and a maximum magnitude for the primary and secondary.

 

Once you get a list going, go outside and try to complete it. You'll see it's a great way to learn more about a patch of sky. Pay attention to the stellar types and the P.A. to help you identify the double in question.

 

 

 

Most importantly, come back here and tell us what you saw!

[Dale Smith]

Very helpful advice, Jordan, and thanks for mentioning Stelle Doppie! I will definitely delve into it. I really like the idea of generating a list and then working to complete it.

 

I’ll report back after the skies finally clear for more than five minutes 

Edited by Dale Smith, 04 March 2024 - 07:05 PM.

[aznuge]

The Orion 100 definitely looks like it should be a great adventure in double stars.  I hope to get to it someday, and also the Cygni 100.  I may wait for the book to come out on the latter - hoping to get an autographed copy .

 

My current double star journey is taking me a different way right now, and its a pedantic one.  But I recently finished observing the final two double stars in Orion that are on my list.  These were tough for me and required multiple instruments and eyepieces to confirm and compare views.  Both of these are multiple star systems.  They both have high contrasts in magnitude, where the glow of a bright primary overwhelms a dimmer, close-by 2nd or 3rd.  And as far as I can tell, neither of these is on the Orion 100 list.

 

Anyway, if you were to look at the constellation Orion, with head up and sword down, the two double stars that I am talking about are close together and at the left end of the belt.  They are Zeta Orionis or Alnitak; and just below it, Sigma Orionis.  The instruments I used, over a few day period, were the Vixen BT126SS-A, the OB BT-127XL-SD, and a supporting refractor - the AstroTech 125 EDL.  Eyepieces included Pentax XW 10, 7 and 5mm; Nikon SW 7 and 5mm, and Baader Morpheus 4.5mm.

 

Zeta Orionis, Alnitak, STF 774 A, B, C

From my log - Very tight, and exacerbated by the brightness of Alnitak. Used several different eyepieces.  A moon and sky glow filter helped resolve the A & B components with a 5mm eyepiece.  Focal length of the instrument used is 625mm.  Still spikes from the primary were present, but underlying dark band separating it from the 2nd was visible.  The distant and dimmer HD 290812 appeared brighter than the actually lower magnitude C component due to the washout effect from bright Alnitak.  STF 774 A,B C.  Components A & B are physically related.  C is not.

 

I will add that I was initially disappointed with the Vixen views - the spikiness of the 1.9 magnitude primary being so harsh.  But with the SW 5mm eyepiece success was visible in terms of separating the 2nd (2.4") by a visible black band under all the starbursts.  On another night I got after Alnitak with the Oberwerk 127s thinking that the view would be better.  But I was surprised that it was very similar to the Vixens, just slightly less harsh, with the separation not being as pronounced.  The best view was with the telescope, on yet a third night.  At 195x Alnitak was easily separated by the AstroTech in concert with the 5mm XWs, and there was very little spikiness from the primary, just overlapping diffraction rings. Would have been nicer to see this in stereo though.

 

 

Sigma Orionis, STF 762 AB,C, D, E

Log - Multiple star system, four stars with Primary Sigma Orionis A, then 2, 3, 4 as C, D, E.  Seeing C was the challenge with its 9ish magnitude within the brightness of the 3.8 mag primary.  Located about 1 degree SE of Alnitak.

 

Component C was definitely the challenge for this system.  Very difficult to see and to hold with the Vixens - until I inserted the 4.5mm morphs.  This worked the trick with component C.  The contrast was such that, once popped, I could hold it indefinitely.  Subsequent views with the OB 127s were not quite as contrasty, with C still visible.  And the AT 125 delivered an equally hold-able view at 195x.  I must say that this multiple star system is beautiful and distinctive when included with HD 294272 A&B and HD 29471 in the same FOV.

 

 

It has been an interesting double star adventure in Orion with these instruments:

 

 

 

Edited by aznuge, 05 March 2024 - 03:32 PM.

[jrazz]

Sigma Orionis is absolutely gorgeous!

 

The more magnification you throw at it the more stars appear. It's a super interesting system!

[Dale Smith]

Thanks for an inspiring account, aznuge, of your double star adventures in Orion. Looking forward to checking these out, when the weather finally allows it (hopefully before Orion disappears from our evening sky 

[Fiske]

The Orion 100 definitely looks like it should be a great adventure in double stars.  I hope to get to it someday, and also the Cygni 100.  I may wait for the book to come out on the latter - hoping to get an autographed copy .

 

,,,

Nuge! You are a glutton for punishment.   

 

Alnitak / STF 774 is 1.74/3.70 at 2.1" separation!  That is deep APO refractor territory, my friend.

 

One thing I maintain about the Oberwerk 120 and 127XL is that they are outstanding instruments, but really better for low to moderate magnifications. The 100XL-SD is actually a better choice for higher magnification views because of how the design scales. 

 

BUT, don't I recall you owning a Takahashi 120?

 

 

That seems like the natural choice here...

[Fiske]

Thanks for an inspiring account, aznuge, of your double star adventures in Orion. Looking forward to checking these out, when the weather finally allows it (hopefully before Orion disappears from our evening sky 

Uh, my advice is to work with more attainable and relaxing binocular doubles near term, Dale. 

 

And your 82XL is a fine binocular double star instrument. 

Edited by Fiske, 05 March 2024 - 10:04 PM.

[aznuge]

Nuge! You are a glutton for punishment.   

 

Alnitak / STF 774 is 1.74/3.70 at 2.1" separation!  That is deep APO refractor territory, my friend.

 

One thing I maintain about the Oberwerk 120 and 127XL is that they are outstanding instruments, but really better for low to moderate magnifications. The 100XL-SD is actually a better choice for higher magnification views because of how the design scales. 

 

BUT, don't I recall you owning a Takahashi 120?

 

 

That seems like the natural choice here...

You may be right.  I've not been in a rush on this, but probably time to take it out of the hangar and let it take flight - at least to see if it has what it takes to be a support refractor on the team.  The AT125 EDL has already proven itself as "not too shabby".  Perhaps its time to see what the TSA 120 can do. 

[jrazz]

Nuge! You are a glutton for punishment.   

 

Alnitak / STF 774 is 1.74/3.70 at 2.1" separation!  That is deep APO refractor territory, my friend.

 

One thing I maintain about the Oberwerk 120 and 127XL is that they are outstanding instruments, but really better for low to moderate magnifications. The 100XL-SD is actually a better choice for higher magnification views because of how the design scales. 

 

BUT, don't I recall you owning a Takahashi 120?

 

 

That seems like the natural choice here...

Totally doable on the BT-100SD!

 

And on the TOA....

 

And on the TDC.....

 

Man, spoiled for choices but it's cold and patchy out there. This is a night for a warm blanket and the MB6!

[aznuge]

...

 

One thing I maintain about the Oberwerk 120 and 127XL is that they are outstanding instruments, but really better for low to moderate magnifications. The 100XL-SD is actually a better choice for higher magnification views because of how the design scales. 

 

...

That should be an easy test for well-aligned samples of the 100 and 127...

[Fiske]

The Orion 100 definitely looks like it should be a great adventure in double stars.  I hope to get to it someday, and also the Cygni 100.  I may wait for the book to come out on the latter - hoping to get an autographed copy .

 

[jrazz]

So, yes. STF 774 is totally doable on the BT-100.

It wasn’t as easy as I thought though. Much like other bright doubles (Rigel, Sirius) the seeing is critical. Still, fun to try and rewarding to split.

[Dale Smith]

I observed a few doubles in Orion this evening, following up on Jordan's post. I observed with the Oberwerk 20x70 EDU, but then brought out the AT80ED support telescope for a quick peek at a more challenging double.

 

STF 688

7.52/7.55 sep 10.5" pa 95.4*

 

A pair of evenly matched, yellowish stars nestled together in a delicate but pleasing field. Fully resolved with the 20x70. A splendid 20x binocular double.

 

STF 692

7.64/8.57 sep 34.89" pa 4.3*

 

Yellow primary with a faint white companion at a comfortable distance in a brilliant field including Rigel, Tau, and e Orionis. 

 

STF 701

6.13/8.09 sep 6.17" pa 138.3*

 

I can detect the secondary in contact with the primary with the 20x70, but can't hold it steadily, just glimpsing it from time to time. But beautifully resolved with the AT80ED support telescope at 56x (Baader Hyperion zoom at 10mm). Bright white primary with a faint sand-colored companion hovering by its side. A pleasing support telescope observation.

 

STF 817

8.68/8.93 sep 18.6" pa 73*

 

A modest but lovely double just south of the fiery orange Betelgeuse. Both stars yellow, evenly matched, close but not tight, easily viewed with the 20x70 EDU. A gorgeous star field.

 

 

I tried finding STF 817 last night with my Pentax 20x60 SP WP but the area immediately south of Betelgeuse was pretty sparse here. My SQM showed 18.77 MPAS and my back yard was protected from local lighting. Of course, the Pentax’s FOV is narrower by half at 2.2 to the 20x70 EDU. It’s also possible that was just off where I looked, too. I went south, and then north, and perhaps at 2.2 degrees I didn’t go south quite far enough.

Edited by Dale Smith, 06 March 2024 - 10:27 AM.

[aznuge]

So, yes. STF 774 is totally doable on the BT-100.

It wasn’t as easy as I thought though. Much like other bright doubles (Rigel, Sirius) the seeing is critical. Still, fun to try and rewarding to split.

Nice! What eyepieces did you use to get the split?

[aznuge]

I tried finding STF 817 last night with my Pentax 20x60 SP WP but the area immediately south of Betelgeuse was pretty sparse here. My SQM showed 18.77 MPAS and my back yard was protected from local lighting. Of course, the Pentax’s FOV is narrower by half at 2.2 to the 20x70 EDU. It’s also possible that was just off where I looked, too. I went south, and then north, and perhaps at 2.2 degrees I didn’t go south quite far enough.

Can’t win ‘em all.  But they all count for experience 

[Dale Smith]

Can’t win ‘em all.  But they all count for experience 

Wise words 

[jrazz]

Nice! What eyepieces did you use to get the split?

TOE 4mm and TPL 6mm.

 

The TPL as usual were better. Less stray light and fuzziness. 

 

The TDC was also used to great effect! (I love this dinky little telescope)

[aznuge]

So, yes. STF 774 is totally doable on the BT-100.

It wasn’t as easy as I thought though. Much like other bright doubles (Rigel, Sirius) the seeing is critical. Still, fun to try and rewarding to split.

For Sirius I have used Nagler Zooms in the 127: 6mm - 4mm were improving views of the pup; at 3mm the B component washed completely out.

For Rigel, Beta Orionis, I recently used 7mm XWs in the 100 SD for an excellent view.

Edited by aznuge, 06 March 2024 - 04:53 PM.

[jrazz]

Those XW's are fantastic eyepieces. Bit too wide for my face but very very enjoyable.