Sirius A & B split

[Dennis]

Hello,

Here are a series of images of Sirius A & B captured from Brisbane on 8th March 2008 using the Tak Mewlon 180 and Televue x2.5 Powermate and later, a TV x3 Barlow.

The seeing was probably 7/10 at best, with spells of 5 to 6/10. The “Pup” (Sirius B) was often visible at the time of capture but as the evening progressed, the slight reduction is seeing made its appearance more sporadic.

In an attempt to verify that I wasn’t “seeing” a processing or system artefact, I rotated the CCD camera approx 90 deg then 180 deg from the starting position and the “Pup” made his appearance in the appropriate location, therefore making this series a good candidate for having captured both A & B.

In visible light Sirius A (Alpha Canis Majoris) is the brightest star in the night sky. SkyTools provides the following data:
AB: -1.44+8.5 mag, PA 97° Sep 8.11" (2008.2)
Sirius is 9 times more brilliant than a standard first magnitude star.

Cheers

Dennis

[sheeny]

Well done Dennis!

Al.

[spacezebra]

Dennis

This is fantastic - I was only raising this at our society meeting the other night - how the two have been moving apart since 1983? Good job!

Cheers Petra

[skwinty]

Good one Dennis
Another notch in your pistol grip.
Regards
Steve:thumbsup:

[Dennis]

Thank you Al, Petra and Steve, I hope you enjoyed seeing the split as much as I did in recording it.

I was simply astonished when I first saw the tiny, but distinct dot of the Pup appear on the notebook display. I really didn’t imagine that the DMK would have the dynamic range of brightness to display both components simultaneously, without B being swamped by the much brighter A component.

A testimony to the amazing arsenal of equipment available to the modern amateur!

Cheers

Dennis

[beren]

:)Congrats Dennis fine work, what an exciting evening to record that

[astro_south]

excellent Dennis

I 'recovered' the Pup a couple of months ago in my 12.5" at around 238x. It was a persistent point within the flare and then would become very distinct for a half a second or so every 5 to ten seconds. I did it again the following month - got the view confirmed (both times) by Darren (dhumpie). Your images (particularly 2 and 3) is similar to the view we had through the eyepiece when it became distinct. Thanks for posting.

[strongmanmike]

Very cool Dennis!

Simple but rewarding.

Mike

[gbeal]

Get sequence Dennis, well done. I have been trying for ages to split this sucker (visually) with no luck, One day (night obviously).
Gary

[Ric]

Well done Dennis, great images of a extremely tricky subject.

I'm like Gary, being trying but no luck as yet.

Cheers

[Dennis]

Thanks Mike.

I am suffering “complex system set up” exhaustion at the moment and just couldn’t face the prospect of setting up and configuring the side-by-side system to use the separate guide scope for some long exposure, auto guided DSO work.:sadeyes:

So, it was an absolute joy to just haul out the rig, plug in the DMK and be up and running in a few minutes. The thrill and experience almost converted me to the life of an eyeballer!:scared:

Right now, the simplicity of visual observing is proving a strong attraction, its effortlessness quite seductive, although I am not jaded enough to subscribe to the black art of star hopping; nor do I want to push a dob!:whistle:

Cheers

Dennis

[iceman]

Very well done, Dennis. A sure sign of a man in control of his collimation, good optics and good camera techniques.

Well done.

[h0ughy]

never cease to amaze Mr Simmons, thats darn clever

[[1ponders]]

:clap: :bowdown:

It's great knowing that we can always count on Dennis to post something that will grab everyones attentions. :thumbsup:

[WadeH]

Thats wonderful Dennis, well done!! Must have taken a lot of patience to achieve all the right elements for that series of pics.

:thumbsup::thumbsup:

[Dennis]

Thanks everyone for your nice comments; I hope you enjoyed the results as much as I enjoyed the speedy set up compared to auto guided DSO imaging!

I actually found that the collimation was a little off when later viewing Acrux (DMK with x2.5 Powermate) and had to tweak the Bob’s knobs a little. I find the Bob’s knobs really tight and difficult to turn on the M180 compared to those on the C9.25.

I haven’t been game enough to play with them too much yet, as how the centre spot moves within the concentric circles of the out-of-focus diffraction rings is a little counter intuitive compared to the standard logic of the C9.25, unless it’s just my dull, aging brain!

Cheers

Dennis

[RB]

What a beaut capture Dennis !
I haven't seen this done all too often, so thank you for sharing.

I sympathise with you, I'm suffering “complex system set up” too atm.
Naked eye obs is always nice to fall back on and one of life's simple pleasures. :D

[Dennis]

I understand that this may seem preposterous, but Sirius B may have also been recorded after I swapped the Televue x2.5 Powermate with its bigger brother, my Televue x5 Powermate at an efl of 10,800mm which is F60!:scared:

Just to refresh our memories, I was using a Takahashi Mewlon 180 F12 (2160mm fl). With the x2.5 Powermate this gives an efl of 5400mm (F30) and with the x5 Powermate, this becomes an amazing 10,800mm (F60).

Originally, I consigned this x5 Powermate 3000 frame avi (movie file) to the “don’t bother processing” bin as whilst it was being recorded, I didn’t see Sirius B on the notebook display as I had done with the x2.5 Powermate. Anyhow, last night I had some spare time so I punched the 3000 frame avi through Registax, stacking 962 of the better frames when lo and behold, Sirius B appeared to arise from the somewhat messy image.

The size of the DMK 21 AF04 CCD chip is 640x480 pixels with 5.6 µm pixels. This gives a FOV of 1.1 x 0.9 arc mins and an image scale of 0.11 arc sec/pixel. Using the Ruler in Adobe Photoshop, I measured the separation to be approx 80 pixels which at an image scale of 0.11 arc/pixel gives a value of 8.8 arcsec for their separation.

The actual magnification of the Televue x2.5 and x5 Powermates varies slightly depending on the distance of the CCD chip (or film plane) from the top surface of the lens, along with no doubt manufacturing tolerances, so the measurements are not absolute as I did not calibrate the imaging system.

Cheers

Dennis

[iceman]

It's definitely there! Well done Dennis!

[Terry B]

Great. I will have to try again.

[Vince G]

G'day all,
Do you think this little star near Sirius is it mate?
Vince G

[Dennis]

At face value, I cannot say from that photo. What is the field of view and the telescope, camera, exposure details, etc? This additional information should provide the image scale and insight into your photo which will greatly help others analyse the photo.

Cheers

Dennis

[Vince G]

I've never studied double stars before so I wasn't sure of this one, but I'm getting more convinced it is the mate of Sirius.

Look at this second image and you will see more stars.
The one at 5 o'clock to Sirius is GSC 5949:2774 and is 5'27" away.

The image scale is 3.29 arc secs per pixel, a cropped image taken with a
QHY8 using a ZS 80 II ED 'scope.

I hope this will help confirming.

Vince G

[Dennis]

Hi Vince

Looking at your image and based on my interpretation of orientation and distance, I don’t think that the smaller star near Sirius is a good candidate for being Sirius B, and here is my reasoning:

When comparing your star field to SkyTools, the smaller companion star in your image seems to be located about North of Sirius A, whereas I understand Sirius B to be East of Sirius A.
Looking at the overall image scale, the distance between GSC 05949-2774 and Sirius is 5’ 27”, which is 327 arcsecs. Using this as a yardstick, I estimate that the distance between Sirius A (centroid) and your candidate star to be around 50 or 60 arcsecs? The published value is just over 8 arcsecs for the year 2008.

I could be wrong, and it would be nice if that were the case! I wonder if anyone else can shed any further light on this, or verify that I have N & E correctly oriented.

Cheers

Dennis

[IanL]

Superb Dennis, I like the projects you do and the findings that you put along with them. Very intresting.

Ian

[Dennis]

Thanks Ian – I enjoy these non-mainstream projects and I’m pleased that others also enjoy the results.

Cheers

Dennis

[Vince G]

G'day Dennis,
You are correct. It is not Sirius B.
I've learnt something. Thanks.

Regards
Vincent

[Dennis]

Hi Vince

No worries. What software or star maps did you use to establish the identity of GSC 05949-2774? I have found quite a variance in magnitude of these fainter stars depending on which catalogue the reference data comes from, such as GSC, UCAC, UNSO, etc.

I also find it quite confusing determining which is E and W in the eyepiece, depending on whether I am using a diagonal or not, or a refractor (single objective) or reflector (2 mirrors). In the end, I just turn off the mount’s motor and see which way the star drifts.

Cheers

Dennis

[Thad C.]

Hello Vince and Dennis,

I have been looking far and wide for other images of Sirius the surrounding star field. I was so thrilled to have Googled yours and the fantastic discussion, that I have just registered.

I am an amateur astronomer in Wilmington, North Carolina, USA. I have jumped back in to this hobby in hopes of learning more about nearby stars. I started with my 40 year old 6 inch reflector and added a modified Logitech webcam. I imaged the brightest star, Sirius, just to learn technique, and rapidly found myself having the same problem: which way is North? I too thought I might image Sirius' Pup. No luck on the Pup (my equipment isn't capable), but I have run into an interesting problem of identifying the stars within 3-10 arcminutes of Sirius. I got into that to match cataloged stars to my pictures in order to find North. That worked, but I have not been able to identify all of the stars in the catalogs so far. I'm just learning the catalogs. I found all except 3 on Simbad.

Here is one of my pictures of Sirius (taken 20 Jan 2008). The field is approximately 7x10 arcminutes. I rotated it to match your picture (which a is much wider field than mine)
Using a match to published stars (and later the method of switching off the drive), I determined that North is about 10 degrees left of the top diffraction spike and East is toward the right. This would put Vince' star about NE.

I don't see the bright star to the NE in my images(Sirius' glare may overwhelm it in my old telescope). But I am so happy to see that you confirm the other stars in the field. I wonder if you or other members of this forum might have similar pictures of the star field near Sirius?

Thanks so much for the opportunity to participate in your forum.

Thad C.
Wilmington, NC, USA

[Dennis]

Hi Thad

Welcome to Ice In Space and it is great news to hear of you jumping back into astronomy. I suspect the hobby may have changed a little, depending on when you temporarily parted ways?

Cheers

Dennis

[Thad C.]

Thanks, Dennis

I appreciate the warm welcome.

You've got that right, however many things are the same. I was an enthusiastic Amateur as a teen, thought I was going into physics professionally. I then diverted into other careers and interests, but kept my 60's vintage Criterion RV-6, getting it out occassionally. (I've dated myself there!) Recently, with access to so much in the way of astronomy advances on the Internet, I felt the urge to get back into it. I have spent about a year and a half in our local astronomy club learning as much as I can. I just purchased a gently used Celestron c11, matched it to a Losmandy G11 mount. I feel like I'm beginning to find out what is possible in modern amateur astronomy.

I have become very interested in Nearby stars - hence the time I've spent on Sirius and other nearby bright stars. But I've also enjoyed other objects and double stars.

Thanks again for the warm welcome!

Thad

[xstream]

:welcome: Thad, Nice to hear you've got back into Astronomy after a long rest. :)
You'll have to tell some of your fellow Cape Fear members to come on down and join in the fun on IIS.

Good luck with your exploits on trying to find the pup. :)

[Vince G]

G'day Thad,
Sorry for my delay.
I uploaded a full image of Sirius taken with a 6 megapixel QHY8 camera.
The field of view is about 170x111 arc mins. A 1 sec exposure.
I hope you can adjust your seeing of this image, it's only a 50% jpeg.

North is up and east is to the left in this image.
If you point your scope south to a star then drive or push the tube down, you will then see the stars move to the northside of your eyepiece.
Again, if you drive or push the tube west, you will see the stars move to the east side of your eyepiece. More mirrors, more changes :)
You may be able to image the pup with your equipment if you can increase the magnification and stack a lot of the images. There are a few good programs freely availabe for that purpose.

Welcome to our group.
Vincent

[Vince G]

G'day Dennis,
The program I use is TheSky6 Pro. It uses the Tycho and UCAC2 plus several others. It's a very good program and not cheap. I use it for astrometry.
Give the tube a little nudge. You should see which way the stars move.
The direction change with odd and even number of mirrors etc.
Regards
Vince

[Thad C.]

Hey Y'all,

Thanks Vincent and xstream , again I appreciate the very warm welcome.

Thanks Vince for your info on your Sirius picture. For some reason I can't see attachments now. I'm trying to figure out if they were somehow blocked by my browser or firewall settings. I clearly could see your previous pictures.
I'll work on it, perhaps there's something I haven't figured out about this site (although I've been using the Internet for 12 or 13 years and computers for more than 30, this is my first forum). Thanks for your advice on the Pup. I'm tooling up for the next clear sky night! With the weather of Coastal NC and my work schedule, I get just a few opportunities per month.

Thank you xstream for extending the invitation to my fellow Cape Fear Astronomical Society members. I will definately convey your good will.

I've been a member of CFAS for about a year and a half. The Society just celebrated it's 25th anniversary. Our sister society is in Australia: the Astronomical Society of Albury Wodonga. My undersatanding is that at least one of our members visited ASAW about 10 years ago.

Cheers and Clear Skies!

Thad

[Thad C.]

Ahh, now I can see the picture Vince,

Thank you!

Thad

[xstream]

You're welcome Thad.

There are a few ASAW (http://www.asaw.org.au/) members who are a part of this forum, I being among one of them.

John.

[Thad C.]

Very nice, John,

I'll mention the contact at our monthly meeting and via the club's list-server.

Thad

[spacezebra]

Hi Thad

Sorry to go off thread subject - We have lost contact with the executive and are very keen to reestablish communication. Can you please pass on my details. I have PMed you also.

Cheers

Petra de Ruyter

Secretary - Astronomical Society of Albury - Wodonga
Secretary - Border Stargaze 2008 Committee

[Thad C.]

Hello Petra,

The Cape Fear Astronomical Society has a new Secretary and possibly a new newsletter editor. I have already extended your Society's greetings through our list-server email. I will contact the new Secretary specifically and also bring this up at our monthly meeting next week.

Thank you for your interest in maintaining contact.

As I have mentioned, I'm new to the forum format. I'm trying to figure out how to respond to your IM.

Thad

[Thad C.]

Hello Vince

Thank you for your nice large-field picture of Sirius. I have blown it up to approximate my much smaller field pictures. Your photo has been quite helpful in my study of the starfield around Sirius. I have been able to match most of the stars to my own images. I have been working with my new Celestron system. I have attached a pic of the field southwest of Sirius which displays one of the stars also seen in your photo. It's about 10th magnitude and I estimate separation of about 193 arcseconds and position angle of about 200 degrees from Sirius on March 25th. I can't seem to get this object to match up. I wonder if you tell me what was the date of your photo? I suspect I'm just making an error, but I also wonder whether there might have been some movement of the object (?). I have rotated my picture to orient North upward and West is to the right.

This is a stack of about 2500 frames. I'm starting to get an appreciation for the type of exposure I may need in order not to wash out the area where the pup might be seen.

Thanks, again,

Thad

[Vince G]

G'day Thad,
I'm sorry, but I cannot enlarge your image, and can't see any stars except Sirius.
It was 4th March at UT 09:36 when my image was taken.
See if you can post another image.
Vince

[Thad C.]

Hey Vince,

Thanks for the timing of your photo. That will help tremendously in my attempt to identify the object in question.

Sorry for the low quality picture. I'm attaching the jpeg as it was produced from Registax, but adjusted in contrast, brightness (to bring out my star in question) and rotated to bring North up and West to the right (taken March 26th, 0214 UT, Celestron C11 with f6.8 focal reducer, Logitech Quickcam 4000, 1/15th sec frames, 2496 frames out of about a 3 min. avi file). The field is approximately 4x6 arc minutes (distance between the unknown object and Sirius is 193 arc seconds (calibrated using 208 arcsecond separation of Epsilon Lyrae) , at a 204 degrees position angle (West identified by separate exposure as drive is turn off).

I'm also attaching some color inverted and annotated pictures (but croppped and compressed). One was taken with my old 6" Newtonian reflector in January and the other is a cropped, color inverted and compressed version of the above March 26th image.

You clearly imaged the object I'm trying to identify on March 4th. Any idea what it is, or how to identify it? I haven't had any luck with online sky surveys or catalogs.

Thanks again,

Thad

[Vince G]

G'day Thad,
I haven't been able to identify it yet either. I use TheSky6 Pro, but it isn't shown, even with the UCAC catalogue.
I'll try and get a better image tonight and do astrometry on it.

You're taking good shots with your gear.
If you want a free sky chart program, have a look at Cartes Du Ciel at
>www.stargazing.net/astropc/< it is supposed to be pretty good. If you get some catalogs you may find what your looking for.

Regards
Vince

[Thad C.]

Thank you for your kind comments, Vince.

By the way, I may not have rotated the right-most image properly, so North may be off a few degrees. The wider field view, though, can be matched with 3 known stars to the SW of Sirius to derive coordinates exactly.

Thanks for the advice re Carte du Ciel. I'll give it a whirl. I have been using Stellarium (which is not so detailed on the small field we've been discussing).

No hope for observing in North Carolina right now, it's raining and expected to be at least partly cloudy for the next week. It's becoming iffy in my backyard for observiing Sirius - only 2-3 hours before it sets behind the trees. I'm beginning to plan other targets. It appears that the immediate areas around other bright, nearby stars have not been explored well recently. Hopefully I'll get a few more attempts this season.

I noticed there is another Sirius A B thread developing with some more photos posted -planning to check that out.

Regards and Clear Skies,

Thad

[Thad C.]

Hello Vince,

Any luck with the astrometry?

Still cloudy here. Planning another attempt to capture the Pup and look around the nearby starfield, but don't expect even a chance for clear skies for several days.

Regards,

Thad

[Thad C.]

Hello my IceInSpace friends!

It looks like this thread has been inactive for a couple of years - but I'll see if anyone is listening.

First I want to thank you all, particularly Dennis, Vincent and Petra for your assistance in my quest of Sirius B and other nearby objects. After some modest equipment upgrades and alot of practice I finally succeeded in imaging Sirius B this Saturday. I will try to attach my 4x image taken from a 640x480 stack of 2900 webcam frames shot at 1/10ths. If I can't recall how to attach the photo, I'll go ahead and post this note, then come back later with the picture.

Once again I and the members of my club (Cape Fear Astronomical Society) greatly appreciate contact with our Australian counterparts in the ASAW.

Thad C.
Wilmington, NC, USA

[Dennis]

Hello, Thad

Well that looks like a definite split. :) During my attempts at splitting A & B, I had several false calls where it was difficult to determine if I was seeing an optical or atmospheric artefact rather than the Pup, but all those indeterminate attempts never showed anything as clear as your image does.

Well done!:thumbsup:

Cheers

Dennis

PS – how high does Sirius get from your observing spot?

[Thad C.]

Thank you for your kind comments, Dennis, it is great to hear from you!

The increased separation of the pair has clearly contributed to this little victory. But arranging the image of primary star toward the West (but somewhat South) at the edge of the mirror (thus being sure the perpendicular diffraction spike coming off the mirror edge does not go due East and overwhelm the Pup) is what I think really did it. I bet you'll have good luck if you try this.

I have never really thought about the altitude of Sirius above our horizon. A good indicator is that only in February evenings do we get to glimpse Canopus which just barely clears the tall pine tree tops. I have judged our horizon at these times at about -54 degrees declination. Since Sirius is at about -16deg, it should be 38 degrees altitude. That seems about right, I'll check it next clear night. How about for you?

Cheers and clear skies!

Thad