The Sissy Haas double star project.

In addition to the many beautiful binaries, there are several observing challenges. This one asks if it’s possible to observe binaries with different magnitudes using apertures at their limits. Those below go from 1.1″ to 4.0″. I have included the SAO numbers.

http://www.billboublitz.com/Haas_Project/Database.html

I made these observing charts and hope to get on with apertures from 90-150 mm,

Nick.

Testing radio astronomy equipment to determine whether it is capable of detecting meteors

I have been experiencing difficulty detecting meteors at LRO.

Today, I obtained the following advice from my radio amateur friend, Bill Watson. As the advice is particularly useful, I felt I needed to pass it on:

If I can detect the GB3VHF Kent Beacon 144.430KHz at LRO then I will be able to pick up meteors from Graves’ radar. Simply put, if this signal can be detected by my meteor radio scatter detection equipment then I should be able to detect meteors adequately for meteor rate recording. The signal will not be large but it will be detectable. If I can not detect the Kent Beacon then I will not be able to detect meteors.

To detect the Kent beacon set receiver to 144.430KHz and CW mode. The beacon is always on (unlike meteor showers!) so if I can’t detect it then there is a problem with my set-up.

(Note Graves is on 143.049MHz and side band).

There is also something else that this test will do which is important – many radio receiver dongles are not accurate on their frequency and the user needs to determine an offset frequency. Once determined this can usually be entered into the software settings to correct the dongle’s frequency. If this has not been done then the frequency on the computer will be inaccurate and meteors will not be detected because the dongle is not correctly set to Grave’s frequency.

To determine the offset simply find the Kent beacon around 144.430KHz – any difference in frequency shown on PC from 144.430KHz is the offset frequency needed.

At LRO (Lichfield Radio Observatory) we are using Moxon aerial (homemade by Bill), FunCube Dongle Pro Plus, Spectrum Lab software, for radio meteor scatter detection from Graves in France.

Andy

Introduction to Observing Double Stars.

I few years ago, I looked through a lovely long refractor . Up until then I’d used Newtonian’s , our school proudly had the only 6″ Newt in the county ! I was completely blown away by the view of the “double double” in Lyra. Not only were the stars pin sharp marbles, but the gaps between them were dark and well defined. Something I had never seen. That hooked me into longish achromatic (f8-f11) refractors and observing double stars. I hope this brief introduction may kick off a few adventures in an often overlooked area.

About half the stars that we see are doubles. The majority were born as triples, doubles and less than a third were single stars. The simplest of equipment will show double stars , their colours and the background field view . Here is the orange and blue of Albireo,


There are optically aligned doubles and binaries which orbit around a common centre of gravity. In addition there are spectroscopic binaries which may , in eclipsing give variable stars. Some of these are so close they react and pull material across the void.
Every constellation , however poor in deep sky objects has an attractive array of easily observable stars. These are ideal for light polluted skies and looking away from the Moon. There is a great deal of history here,reflected in the Herschel , Struve and Burnham catalogues. You can tread in their footsteps and discover very rewarding targets.
Diffraction discs.
Your scope produces Airey rings or diffraction discs of stars at focus. It’s not actually the surface of the star, but the best disc that your scope can produce.
Separation.
Is measured in arc seconds (“). This is an angular measurement equivalent to 1/3600 of a degree.Some quoted separations are widening and some narrowing. The WDSC ( Washington double star catalogue) is continually being updating by amateur observers measuring separations. The close limit is down to the optics, the observer and the seeing (stability). We got down to 1.1″ on 36 Andromedae in both a 5″ and 4” refractor. This is a good minimum for our skies.
Colour.
This is very subjective, stars change colour with age, going through to red carbon stars. However it’s possible to observe colours from lilac to green ! Larger apertures will bleach out colour. 4″ of refractor aperture is the most efficient optical system producing maximum colour. Short refractors will add their own colour fringing due to chromatic aberration (CA), this can be avoided by using longer refractors. A semi apo filter can be added to eliminate ça, there is little advantage in using an apochromatic Triplet for observing. They are harder to make,heavier and more expensive.

The enjoyment of binary stars is the challenge of finding and splitting them and their lovely colours, often there can be great contrast in brightness. Some are multiple groups, such as Meissa.
PA.
Often quoted is the position angle between the star and it’s companion. It’s a useful indication of where to look .
By eye.
There are a few that can be spotted, the optical Alcor Mizar and the pair in the Hyades.
Sources.
Star charts will denote doubles by means of a line through the star. Often they are named as a Struve (Σ) , Otto Struve (ΟΣ) etc. Many named stars are binaries. The following sites are useful,
200 most beautiful stars   http://users.compaqnet.be/doublestars/#a08268
Star splitters.   https://bestdoubles.wordpress.com/
Sky and Telescope,” 2100 double stars for small telescope” by Sissy Haas.
Cambridge “Double Star Atlas”.

Some current doubles.
Gemini.   Separation.  Mag.1. Mag2.   Observations.
Wasat      5.8″.       +3.6.   +8.2    Yellow and a delicate speck of a companion.
Castor.     4.2″.       +1.9.   +3.0.    Further companion at 71″.
Mebsuta.   110.6″.     +3.1.   +9.6.    White and blue.
Kappa Gem. 7.2″.       +3.7.   +8.3    Orange and pale blue. (SAO 79653)

Leo.
Regulus.   176″.       +1.4.   +8.2.    White and delicate pale purple.
Algieba.   4.6″.        +2.4.   +3.6.    Pair grapefruit orange.
90        3.4″-67″.     +6.3-+9.8.       Lovely triple. (SAO 99673)

Ursa Major.
65.      3.9″-63.2″.     +6.2-+8.3.       Triple. (SAO 43945)
57.      5.5″.          +5.4.   +10.7.   White and violet.
53.      1.7″.          +4.3.   +4.8.    “Alula australis ” showcase.

Cancer.
Iota Cancri.   30.7″.       +4.1.  +6.0    The winter Albireo.
Tegmine.   1.1″-5.9″.      +5.1-+6.3      Bright challenging triple. (SAO 97645)

Canes Venatici.
Cor Caroli.    19.3″.      +2.9.  +5.5.    White and blue green.(SAO 63257)

There are plenty to observe and various challenges and projects, such as the “Double Star challenge”, which I made a start on observing and recording from smaller apertures. http://www.billboublitz.com/Haas_Project/Database.html
I hope this has started a few journeys into double stars, under
Clear skies !
Nick.

 

 

RAG meeting review 24/2/2017

Around 30 people attended the February meeting of Rosliston Astronomy Group.

Ken Critchon gave a great talk on hisCekestron 11 inch EdgeHD telescope. He bought this mammoth beast along with him. It is the first scope I have seen that makes a DSLR look like a tiny camera on the end and the only one which uses a Takahashi as a guiding scope (I am not entirely fair – he also uses it for wife field images).

After Ken’s talk, I showed a video from Astrofest 2017 in London with special guest star Jon Curshaw, the impressionist and friend of the late Sir Patrick Moore.

We had a longer than usual coffee break to give members a chance to chat and meet new friends.

Then several members gave short talks on items of interest in astronomy – including books, hardware and websites – something new for the club and a great success!

Ken giving his talk:

Ken with his telescope:

Ken talked about periodic error during photography and other advantages of the EdgeHD and it’s dedicated mount for astrophotography:

Roger talked about his Bresser Mikrokular camera. He showed us his homemade telescope from part binocular and part drain PVC tube:

Peter Simkin discussed astrophotography using DSLR in light polluted areas:

Geoff Dryland talked about his favourite book on process astrophotographs:

Andy McIntosh bought in three books that really made a difference to him:

Stephen Sanders discussed his favourite book about Greek mythology related to the stars:

Kathy Hassell talked to us about her favourite internet resources:

Finally, I bought along a box of bits and pieces that interested me.

Andy

Club member reviews at end of night:

1. Length of session shorter than normal – widely liked.

2. Variety was also liked.

3. Thumbs up for short member presentations – but not wanted every month.

4. Astrofest review – some members liked this video, others less do – seemed to depend on whether members were type that liked to go to astronomy conferences. Speakers weren’t that loud and this made it difficult to hear. Also directional microphone used by Andrew should be supplemented with lapel microphone for himself so he can be more easily heard. For those that did like the video they felt its length was fine at 15 mins but would not have wished it to be any longer in length.

5. Jon Curshaw video – although funny unfortunately it was difficult to hear -unlikely to be able to overcome this problem and hence avoid such videos in future.

6. In spite of above, the evening was greatly enjoyed and there were requests to repeat it at some stage in future.

Winter Albireo(s).

 

Just before dawn, Hercules is high at the zenith and the whole of the Summer Triangle is up. Looking at Albireo this morning reminded me of the several contenders for winter Albireo. In addition Rasalgethi in Hercules gives an orange and blue combination.The best contender must be Iota Cancri.
Albireo.
+3.4 +4.7 at 34.7″ separation, giving orange and royal blue.

Rasalgethi
+3.5 +5.4 at 4.8″, giving orange red and blue turquoise.

Iota Cancri
+4.1 +6.0 at 30.7″, giving yellow and royal blue.

HJ 3945 in Canis Major. SAO 173353.
+5.0 +5.8 at 26.8″, giving citrus orange and royal blue.

Colours spring out in smaller aperture , with 4″ giving maximum effect.

Clear skies !

Nick.