Absolute Beginners

 

If your new to Variable Star observing, and would like a few recommendations as to what are the easiest and best placed stars to observe for a particular season, then you have come to the right place.

 

 

 

 

 

Below are listed ten stars each for Spring, Summer, Autumn and Winter - five telescopic and five binocular. By clicking on the star name, you will be taken to the chart for that object.  For Mira stars, don't forget to check the predictions page for an idea as to when maximum and minimum occur.

 

 

 

This page is also available as a PDF download

 

Finally there are a couple of useful hints and tips which will help you make your first (of many) observations!

If you need assistance with any of the objects below, do not hesitate to contact any of the VSS officers!

 

 

*  = both binocular and telescopic object.   This indicates that occasionally the star may get brighter than magnitude 8, at which time the variable is better observed with binoculars or a very small telescope!

** = Circumpolar

Spring

Binocular

star Type Range Period Frequency
V CVn SRa 6.5-8.6 192d 5d-7d
AH Dra ** SRb 7.0-8.7 158d 5d-7d
X Oph Mira 5.9-9.2* 328d 7d-10d
Z UMa ** SRb 6.2-9.4 196d 5d-7d
RY UMa ** SRb 6.7-8.3 310d? 7d-10d

 

 

 

 

 

Telescopic 

star

 Type Range Period Frequency
U Boo SRb 9.8-13.0 201d 5d-7d
V Boo * SRa 7.0-12.0 258d 5d-7d
R CrB * RCB 5.7-15.0 NA Nightly
V CrB * Mira 6.9-12.6 358d 7d-10d
X Leo UGSS 11.1-16.5 17d Nightly

 

 

 

 

 

Summer

Binocular

star Type Range Period Frequency
W Cyg SRb 5.0-7.6 131d 5d
CH Cyg * ZAND+SR 5.6-10.5 NA Nightly
AC Her RVa 6.8-9.0 75d 5d
ST Her SRb 7.0-8.7 148d 7d
R Sct RVa 4.2-8.6 146d 7d

 

 

 

 

 

Telescopic 

star

 Type Range Period Frequency
chi Cyg * Mira 3.3-14.5 408d 7d-10d
SS Cyg * UGSS 7.7-12.6 50d Nightly
SS Her Mira 8.5-13.5 107d 5d-7d
YY Her ZAND 11.1-<14.0B NA Nightly
V Vul RVA 8.1-9.5 76d 5d-7d

 

 

 

 

 

Autumn

Binocular

star Type Range Period Frequency
U Cam ** SRb 7.7-8.8   ? 5d
SS Cep ** SRb 6.7-7.8 90d 5d
AF Cyg SRb 6.4-8.4 92d 5d
Y Lyn SRc 6.5-8.4 110d 7d
Z Psc SRb 7.0-7.9 144d 7d

 

 

 

 

 

Telescopic 

star Type Range Period Frequency
Z And * ZAND 8.0-12.4p NA Nightly
RX And UGZ 10.3-15.1 14d Nightly
X Cam *  ** Mira 7.4-14.2 144d 5d-7d
omicron Cet * Mira 2.0-10.1 332d 7d-10d
RU Peg UGSS 9.0-13.2 74d Nightly

 

 

 

 

 

Winter

Binocular

star Type Range Period Frequency
X Cnc SRb 5.6-7.5 195d 7d
TX Dra ** SRb 6.6-8.4 78d? 5d
RY Dra ** SRb? 6.0-8.2 200d 7d
BU Gem Lc 5.7-8.1 47d? 5d
U Mon RVB 5.9-7.9 91d 5d

 

 

 

 

 

Telescopic 

star Type Range Period Frequency
T Cas * Mira 6.9-13.0 445d 10d-14d
U Gem UG+E 8.2-14.9 105d Nightly
U Ori * Mira 4.8-13.3 368d 10d
AX Per * ZAND+E 8.0-13.0 NA Nightly
RV Tau RVB 8.8-11.0 77d 5d

 

 

 

 

 

Eclipsing

New charts for Algol and beta Lyra are waiting to be drawn.

star Type Max Min II MinI Period d Eclipse Duration (h)
Algol EA 2.1 2.2 3.4 2.87 10
RZ Cas ** EA 6.2 6.3 7.7 1.2 5
U Cep ** EA 6.8 6.9 9.4 2.49 9
beta Lyr EB 3.3 3.9 4.4 12.91  
W UMa EW 7.8 8.4 8.5 0.33  

 

 

 

 

 

Tips and hints

Measure the (true) field of view for each eyepiece you use, and attempt to identify your telescopic limiting magnitude.  These two basic steps will help you in identifying the field and comparison stars more easily.

To measure the diameter of your eyepiece, point the telescope to a star with zero degrees declination.  Time the interval it takes for the star to pass from the eastern edge of the field of view, through the centre, until it disappears at the western edge.  Multiply this by 15 to give the true FOV for your eyepiece.  Repeat for each eyepiece in use.

Try to identify the field in which the variable lies rather than look for the variable itself.  See if you can identify the comparison stars and the patterns they make.  On some occasions the variable might be fainter than your telescopic limit, in which case you will never find it until it brightens again and enters your telescopic range.

If you have a drive on your telescope, switch it off and watch which way the stars move.  This is West.  Orientate your chart so that the west point on the chart is aligned with the motion of the stars.  This will help you ID the field more easily.

Chart orientation can be confusing.  Classical Newtonians have North to the bottom and West to the left.  SCT's and Refractors using a diagonal (which  most do) have North to the top and West to the left.

Red stars when bright can prove difficult to measure reliably.  De-focus the variable and comparison star to make your estimate.  This is especially helpful if you're observing red stars with Moonlight interference.

Try not to over observe the stars on your programme.  The frequency number shown above is the ideal period as to when your stars should be observed.