A Sirius Matter -Plus-DOUBLE STAR TIPS -

[AG Hybrid (Adrian)]

Originally Posted by Tropo-Bob

Adrian, that is a huge achievement if you found it in such a small scope with CA issues as well. However,I am confused about your use of the clock for directions. The Pup should trail Sirius A in an undriven scope. If I am using the clock in the same manner as yourself, my observation was that it was at about at 7 o'clock position. Given that you saw it in your 12" reflector at the 11 o'clock position, I thought our observations were in agreement when you swap the up and down positions between at refractor and a reflector. (Left and right being unchanged of course).
However, you say that you saw it at 2o'clock in the refractor.
I am not saying that you did not see it, but was there anything else going on to confuse the directions; like did you have the star diagonal twisted to the side or something?

Actually your right. I was thinking about another double that I split when I typed that. It was trailing at about 10 O'clock. But damn it was hard. Also to remember that the location of the Pup changes drastically between 7:30 PM and 10:30 PM at the moment. It looks like more than 90 degrees. I was observing for more than 3 hours last night and I looked at Sirius every hour. It could have been a false ID now that I think deeper about it. It was so difficult.

[bigjoe (JOSEPH)]

Originally Posted by skysurfer

Yesterday night tried again, from South Africa, seeing was rather still with ED110 + WO dielectric diagonal + Vixen LV6 (128x), but no pup.
Tonight another try.

In Holland many people claim to see the Pup despite Sirius never comes higher than 21 degrees above the horizon. But I disagree.
https://translate.google.com/transla...ius&edit-text=


11. As few glass-air transitions as possible.

Thanks for NO: 11 skysurfer I'm sure we'll need to add even more tips!

And one has to wonder how they can see Sirius B in such a low altitude with probably a boiling image through the EP!!

Cheers bigjoe.

[bigjoe (JOSEPH)]

Originally Posted by AG Hybrid

Actually your right. I was thinking about another double that I split when I typed that. It was trailing at about 10 O'clock. But damn it was hard. Also to remember that the location of the Pup changes drastically between 7:30 PM and 10:30 PM at the moment. It looks like more than 90 degrees. I was observing for more than 3 hours last night and I looked at Sirius every hour. It could have been a false ID now that I think deeper about it. It was so difficult.

This just highlights the extreme difficulty one can face just to get yourself set up for this task: am I using an upright diagonal : is it reversed East/West : in what direction is my mount/ scope pointed from North as position angle is taken from an imaginary line on the celestial sphere due North , increasing North to East in a clockwise direction - East following here as in Sirius B being roughly around 90 degrees or more position angle: right magnification and resolving exit pupil etc, etc.

bigjoe

[AG Hybrid (Adrian)]

Originally Posted by bigjoe

This just highlights the extreme difficulty one can face just to get yourself set up for this task: am I using an upright diagonal : is it reversed East/West : in what direction is my mount/ scope pointed from North as position angle is taken from an imaginary line on the celestial sphere due North , increasing North to East in a clockwise direction - East following here as in Sirius B being roughly around 90 degrees or more position angle: right magnification and resolving exit pupil etc, etc.

bigjoe

Sure this. Or big newt.

[bigjoe (JOSEPH)]

Originally Posted by AG Hybrid

So... as an experiment I followed the advice that has been given so far in this thread and really gave a proper go.

I can now say I did it. It took me to the very limit of my skill and experience but I DID IT! I spotted the Pup for the first time in my $400 Explore Scientific AR102.

It took some experimentation especially deciding which view was best between using a Baader Semo-Apo filter or no filter. The CA was overwhelming on Sirius so I used the filter at the expense of a little bit of light lost.
I put my 2x barlow in front of my diagonal as to produce more magnification as it would if it were behind the diagonal and then putting the eyepiece straight into the barlow.
I then used a Baader Hyperion Zoom to gauge the best magnification and exit pupil the atmosphere would support. Atmospheric seeing was decent tonight as I observed Jupiter prior, as it rose. I was able to see four bands on Jupiter which was pretty good for the AR102 especially considering how low it was in the sky.

The advise to use Rigel in Orion as a benchmark and test object is a very wise idea. It gave me an idea what I was in for and I noted that CA was overwhelming too. Had to use the filter and glad that I did because it was the first time I saw Rigel B in the AR102 as well. While still lots of CA the little white dot was there with direct vision. Nice.

So, to Sirius. This was hard. Very hard. As I mentioned earlier the CA caused by Sirius was overwhelming at the magnification I was using. Would have been well over 200x. I would approximate that over 40% of the field was blue haze. The filter was necessary. It did a good job, the CA was less then 10% of the field now. Still rather intense around the Sirius itself, just contained. Using the zoom I gauged the best magnification to find that sweet spot between image brightness and contrast. This took some time. I also was using an alt azimuth mount which means Sirius was always on the move and moving fast. It was only a for a few seconds in the center of the field where the best field correction is and my windows of best observing were constantly being reset. But, I've never owned a tracking mount so it was second nature to me. Muscle memory even.

While watching Sirius floating from top left to bottom right going through the field it appeared as it floated through the center of the field. For about 4 seconds the little white dot appeared on the outer most diffraction ring. It looked to be about 2 o'clock. I'm certain it was a positive result as I had spent the last 30 min noting false-positives caused by eye floaters. I don't have many but they are really obvious when they do appear at that tiny exit pupil. I knew exactly how the floaters looked and how the moved and acted. That little white dot I saw stuck right by Sirius as it zoomed through the field of view. The eye floater moved around and rarely in a straight line.

Pretty pleased with that as a whole. Although next time I'm just going to roll out the 12"

The use of a zoom and filters are great ideas Adrian, that should be number 12/13 on the useful tips list-helping to find the right mag and exit pupil for the seeing, and task at hand- good ones !

Morton has of yet not been able to do it in his 100mm tak either from last accounts, so it must be very difficult at this aperture but was easy for you in the 12"!

Who knows for sure-More attempts I guess just to make sure.

bigjoe.

[MattT]

Originally Posted by Allan

There are numerous reports of seeing it in good quality 4" refractors. I think the 3" size might be stretching the friendship, but it is up to us Southern Hemisphere observers to try.

I'm going to add:

#12. Use a long focal length Achro.

I tried again on Saturday night and got the Pup in the 10" no problems. The E+F stars in the Trap were visible too.

So onto the 70mm f13 Achro. Yep this 70mm is well in the Conrady scale for CA at about 4.5. Sirius was a white star, shown as an Airy disc with a couple of diffraction rings, dimmer and a lot less scatter than the 10".
I got a result that was surprising to me but more on that later as I need to try it again on another night.

In the meantime read this article by Neil English...love him or otherwise

http://www.cloudynights.com/page/art...-fiction-r2452

This is turning into an epic thread.

[MortonH]

I tried several times again last night but no luck. Dozens of false positives caused by speckling or tiny reflections that look like it. My problem is most likely that from home I can only see Sirius from my west-facing balcony overlooking a busy road. Since it's been baking in the sun all day the local heat signature, plus the traffic, disrupts the seeing.

[bigjoe (JOSEPH)]

Originally Posted by MattT

I'm going to add:

#12. Use a long focal length Achro.

I tried again on Saturday night and got the Pup in the 10" no problems. The E+F stars in the Trap were visible too.

So onto the 70mm f13 Achro. Yep this 70mm is well in the Conrady scale for CA at about 4.5. Sirius was a white star, shown as an Airy disc with a couple of diffraction rings, dimmer and a lot less scatter than the 10".
I got a result that was surprising to me but more on that later as I need to try it again on another night.

In the meantime read this article by Neil English...love him or otherwise

http://www.cloudynights.com/page/art...-fiction-r2452

This is turning into an epic thread.

I'm a Neil English fan -so glad you brought this up.

My favourite scope type ever is a long f/ratio Refractor. I can well remember the images Of Mars etc in my now sold 4" F/15 Unitron -Never seen better since, except maybe Mars one night in May back in a 7" Mak; it was that good.

Just had a quick read, and he talks about the greater DOF, less spherical aberration, height above ground of the objective , and greater encircled energy per given strehl, all adding to a STEADIER image than say an ED doublet, but less so for a triplet and he says contributing to less eyeball strain in these long F/ratios.

HOW GOOD THIS WILL BE FOR OBSERVING DOUBLES ;WE MAY SOON FIND OUT FROM YOU MATT!

Wishing you goodluck with this!

bigjoe.

[bigjoe (JOSEPH)]

Originally Posted by MortonH

I tried several times again last night but no luck. Dozens of false positives caused by speckling or tiny reflections that look like it. My problem is most likely that from home I can only see Sirius from my west-facing balcony overlooking a busy road. Since it's been baking in the sun all day the local heat signature, plus the traffic, disrupts the seeing.

Just for a lark I tried a 30min look again at midnight last night, in a 10 SCT , and 13mm T6 nagler-no luck at all either!!

bigjoe
.

[bigjoe (JOSEPH)]

Originally Posted by Bombardon

In case the time poor star splitter missed it in a previous post I grabbed this link from the last on Sirius and is a great article by the famous William Herschel on his viewing techniques, with a lot on optics and light.You will need time and a cloudy night to fully absorb this. PS: you can see I am getting viewers' cabin fever

http://rstl.royalsocietypublishing.o...ge=1&view=FitH

Had a quick read last night .It was interesting, and logical at the time I'd imagine, to use star brightness to calculate stellar distances. His thoughts on the effects of central obstruction , and aperture on resolution and the way he would just create the formula needed to solve a particular problem - His construction of huge scopes and double star, and DSO observations -all a great read.
He would have been a fascinating person, like Halley to have at the dinner table- Musician : writer of symphonies that are still played :discoverer of infra-red radiation, and discoverer of Uranus etc ,etc-PHEW!!

bigjoe.

[bigjoe (JOSEPH)]

Summary of some of the things you may need to do to see any difficult double, including mainly the PUP here.

1: SEEING- Must be excellent.

2: ALTITUDE - Well above the horizon in
most instances.

3: APERTURE-100mm+Cooled and well collimated, though probably no more than 12" due to the affects of seeing on large obstructed scopes.

4: POWER- The use of it is necessary- helps darken sky background and with limiting magnitude ;200x + may be needed.

5: USE A MASK- Hex , may be necessary.

6: ORIENTATION- Is your diagonal/scope displaying an upright E/W view; If not adjust accordingly.

7: PRACTISE on Rigel say - Bright, with similar separation. Know what a separation of 10" will look like in your go to EP -VIZ- Know your field.

8: DRIFTING- Let Sirius A drift past the field stop , and disappear, as B will surely follow.

9: WARM CLOTHING , and stool if necessary.

10: PATIENCE- and lots of it -It could take many attempts!

11:LESS GLASS-Use of EP with fewer elements 4/5 max to increase contrast and detection may be of help.

12:AVERTED AND DIRECT VISION-Go back and forth between direct and averted vision until the companion is held in direct view.

13: ZOOM EP - Use of a good marked zoom EP, to find the optimum power for the seeing and filters if necessary.

14:HIGHLY ACCURATE FOCUS-TOGETHER WITH A NICE FLAT FIELD, FREE OF CURVATURE -this is a must also , and you may have to re-focus often.

15:VERY STABLE MOUNT-Absolutely no wobbles!

16:VIEWING AT TWILIGHT- Can reduce the glare of Sirius A -and this goes for other bright primary doubles as well!

No doubt more things will be needed to be added as we go along ; perhaps long focal length small aperture achromatic refractors as Matt has will be of great use -reports due soon!

bigjoe.

[AG Hybrid (Adrian)]

Eyepieces with green writing on the side. The brighter the better.

Observe from 3 km above sea level.

Observe in winter. The skies are darker and nights are longer.

Eat lots of carrots.

[bigjoe (JOSEPH)]

Originally Posted by AG Hybrid

Eyepieces with green writing on the side. The brighter the better.

Observe from 3 km above sea level.

Observe in winter. The skies are darker and nights are longer.

Eat lots of carrots.

Yes Adrian- "Eat lots of carrots", should have been No.1
on the list; our mums were right weren't they!

And yes EP's with bright green writing, usually are the best

Observe in Winter crisp skies -yes.

And elevation above sea level, I guess has got to go on the list, though perhaps not some of the others!!

bigjoe.

[Tinderboxsky (Steve)]

In my opinion, accurate focusing is essential and should be added to the list. I have a home made, soft touch 17:1 fine focus on each of my scopes. It helps to give very accurate focusing.

Steve.

[bigjoe (JOSEPH)]

Originally Posted by Tinderboxsky

In my opinion, accurate focusing is essential and should be added to the list. I have a home made, soft touch 17:1 fine focus on each of my scopes. It helps to give very accurate focusing.

Steve.

Will do this Steve.

ASAP Fine soft touch focusing 17:1 that is good!!!

And I think also Steve, your suggestion elsewhere of a "rock steady mount".

Cheers bigjoe.

[skysurfer]

Originally Posted by bigjoe

This just highlights the extreme difficulty one can face just to get yourself set up for this task: am I using an upright diagonal : is it reversed East/West : in what direction is my mount/ scope pointed from North as position angle is taken from an imaginary line on the celestial sphere due North , increasing North to East in a clockwise direction - East following here as in Sirius B being roughly around 90 degrees or more position angle: right magnification and resolving exit pupil etc, etc.

bigjoe

It is simple: the Pup is on a PA of about 90 degrees (i.e. East) of Sirius A, which means that it is moving 'after' A with a steady scope, regardless of orientation or diagonals.
A trick is moving the star to the very edge of the field and let A disappear and then B should reveal briefly.
I'll try on the first night with decent seeing.

[skysurfer]

Originally Posted by AG Hybrid

Eyepieces with green writing on the side. The brighter the better.

No, these eyepieces have lots of glass-air transitions which means more scattering. Nice for widefield and many other uses, but not for this critical observation. Use eyepieces with a very simple design like Plössl or orthoscopics.

Originally Posted by AG Hybrid

Observe in winter. The skies are darker and nights are longer.

In winter the skies are not darker, unless you observe from high latitudes (> 50 deg, e.g. N. Europe or Canada).
In the southern winter, the sky is even lighter because the brightest parts of the Milky Way are high in the sky. And Sirius is low if visible at all.

[bigjoe (JOSEPH)]

Exactly skysurfer -as I've stated in No.8: And also EAST 90 deg stated earlier; it should follow after letting Sirius A drift past the field stop.
Cheers and thanks for your input.

PS: Let us know how you are going with this.

bigjoe.

[AG Hybrid (Adrian)]

Originally Posted by skysurfer

No, these eyepieces have lots of glass-air transitions which means more scattering. Nice for widefield and many other uses, but not for this critical observation. Use eyepieces with a very simple design like Plössl or orthoscopics.

In winter the skies are not darker, unless you observe from high latitudes (> 50 deg, e.g. N. Europe or Canada).
In the southern winter, the sky is even lighter because the brightest parts of the Milky Way are high in the sky. And Sirius is low if visible at all.

LOL. Those jokes went straight over your head. Its nigh impossible to observe at over 3km in Australia. Sirius is also a summer object.

Also, Delos and Pentax eyepieces are perfectly acceptable for double star viewing. If you stareing for long periods at tiny objects comfort at the eyepiece is also import.

[bigjoe (JOSEPH)]

Ha, Ha-Their Plossls are good for this though , not so much their widefields it seems and your generally right as they are not truly orthoscopic ; but Adrian does not seem to mind if the glass used and construction has very low scatter it appears and high quality , as a poorly made plossl could indeed be much worse!
PS: I still use the best of their widefields though at times!

Got this down as NO:11- LESS GLASS.

bigjoe.