'Tabelle 9.

D3 h w.F. E n

r r ' l s 10Y4 A I ? Z 8 913 *0:'3 ioY7 8 ~ ~ ~ ' 1 11.9 0 . 2 0.7 8 1 9.0 0.2 0 .5 8 t 4 4 11.4 0.3 0.8 8 I 8.9 0 . 2 0.7 8

I Ha ' h w.F. E I(

+ 1 3 11.6 o I 0.4 1 2 I 8.9 0.1 0.4 1 2

- 1 5 1 1 . 2 0 .3 0 . G 6 i 9.3 0.4 0.9 6 -43 ~ 1 2 . 2 0 . 2 10 z 0.4 1.1 h - 76 10.6 0 . 2 z:: ~ 8.8 0.5 0.9 4

Durch ilbnehmen dcs rcitlichen Clases und Aufsetzen der Hlende steigern wir die Intensitit der rotcn Linie H, ungefahr auf das Doppelte und ein wenig mehr die Intensitat der gclben L ink D,. Die sichtbare Hohe der Chromosphare mul3 in der L ink D3 mehr als in der Link H , steigen, was auch in dcr Tat beobachtet wird.

J c lichtstarker Refraktor und Spektroskop sind, je geringere VergroOerung und Dispersion von uns angcwendet

werden (wohl in bcstimmten Grenzen), je durchsichtiger die Luft ist, desto groBer ist die sichtbare Chromospharenhohe. Gewohnlich benutzt inan bci Chromosphlrenmessungen Refraktoren, die weniger lichtstark, und Spektroskopc mit starkercr Dispersion, als es in Simferopol der Fall war. Hierdurch wird es, wie uns schcint, erklart, daI3 die in Sim- feropol gcfundene Chromospharenhohe groner ist als die von den anderen Stcrnwarten angcgebene.

Mit cinern an das Okular angcschraubtcn gewohnlichen photometrischen Keilc kann man bci Beobachtung der notigcn VorsichtigkeitsmaBrcgcln photomctrische Messungen der Chromosphare ausfuhren und die sichtbare Hohe der letztcren mit Hilfc des Mikromcters bestimmen. Es ist natiirlich not- wendig, bci genauen photometrischcn Messungen die Linie If, vom kontinuierlichcn Sonnenspektrum zu isolieren. Der- artige Messungen wiirden das Rild der Verteilung der Chromo- sphiirenhelligkeit am Kande der Sonnenscheibe wiedergeben und dic F'rage iiber die Messung der Chromospharenhohe vollstandig losen.

Sternwarte Pulkowo, September 1926. .. . E . Perepelkin .

On the variable star VZ Herculis. By W. %essewitsch. The variability of V Z Herculis was discovered by

M. Worf. The star received the preliminary designation 38.1919 Herculis. The first investigation of it was published bv B. Leiner in AN 507; and B Z 1920 Nr. 13 and 24.

The elemepts obtained by Ledner are represented in the following form :

M a x a = 2422388.496 J.D. + od44032 .E and Max - Min = odo4.

Moreover a light-curve was derived too. The photographic observations of J. Haux, hJwever,

show that at the instant of Max., obtained from Leincr's formula, a Min. of the star occurs, and that thc correction of the ephemeris reaches O'!I or 'I4 of the period.

1 carried out my observations in order of my programme work on the short periodical Cepheids. from Sept. 6 to Oct. 14 1926 i. e. through 86 periods. The observations were per- formed by means of a 81/2" Calver reflector with magnifying power I 2 0 . The total number of 85 observations was preferably donc in moonless nights.

The following stars of comDarison were uscd: u 1855 d 1855 st.

a=RD+3G02835 = 1 7 ~ 7 ~ 7?4+36"19!9= 0.00 C = 36 2836- 7 36.7 6.2= 5.45 e=Anonyma = 7 49.3 8.2 = 10.15

f = D = 8 10.0 13.1 = 1603 Designations, positions and brightness in steps are

taken from the work of Leinrr (AN 5077:. All observations werc recomputed by me by the following

method: a sheet of transparent paper with the mcan curve drawn upon it was put upon an other sheet of paper, where the observations were marked in the same scale, moving it ti1 the best adaptation was reached. So I obtained the moment of the upmost briyhtness of the star. So Leiner's and my own observations were treated anew.

Haas' observations were reduced to one period by my second morc precise formula. Making them to be compatible with the visual curvc I go tan approximate epoch of Max. I Y u d observations are tco few to have influence on the possible difference of the curvcs.

Besides a n important one of /laas' observations evidently has a wrong datum [2424409.346 J.D.], for, during of a n hour thc variable could not lowcr its brightness by the whole ampli tudc.

Thc epochs of Max. obtained bv this method are re- presented in the following table: Observ. E Maxima o c' c" 0-c' 0-c" Leiner - 9 2422384.533 .533 ,538 0.000 -0.005

>) - 2 387.614 .615 .620 -0.001 -0.006 )) o 388.494 .496 .500 -0.002 -0.006 )) + 41 406.548 .549, .550 -0.001 -0.o02

H + 93 429.446 .446 -443 0.000 +0.003 n +- 143 451.463 .462 .455 +O.OOI +0.008 )) + 152 455.426 ,424 .417 +0.002 +o.oog

Haas +4527 4381.484 .384 .478 +O.IOO +0.006! Zess. +5399 765.370 ,343 .369 i 0 . 0 2 7 + O . O O I

0 +5401 766.251 234 .250 +o.o17 +O.OOI

)) + 5415 772.413 .398 .413 + O . O l ~ 0.000

J) +5449 787.379 .3G9 .381 i -0.010 -0.o02

)) +5451 788.263 ,250 .263 +0.013 +O.OOI

o +5467 795.303 .295 .306 +0.008 -0.00.3

)) +5485 803.230 .221 .230 +0.009 0.000

c' and 0-c ' apply to Leiner": formula:

and C" and o-c" apply to my new formula: Maw= 2422388.500 J.D. + od4402425-E

derived from all the cpochs by the method of least squares. The fact that the epochs of Leiner's maxima determined

without any presumption from my part, clearly represent a n

. M ~ x o = 2422388.496 J.D. +Od44032.E

exquisite inner concordancc with the period od44032, may be explaincd by a probable variability of the period only.

The maximum observed by Hags can be incorrect only bv odor, so its deviation from the ephemeris with the period Od44032 cannot be ascribed to an error of observation. star is rather seldom observed in order to determine the order L z z-L and law of the change of the period; so a further investigation is required. It is yuite possible that the star has a constant light-curve, while its period is variable.

The last fact makes this star a very interesting onc. It may be of great influence in the theory of cepheid-stars.

lirom my observations a mean light-curve of the variable (Table II), different from Leiner's curve only in the

amplitude, was derived; but the formulae of the two curves are very similar oneanother.

Leiner's curve can be reduced to my curve by shortening, the amplitude by means of the formula

This HL, ,7=H1;0.7896-1?~09.

772.242 e 84 v I : f: +0.269 15.08 Leningrad, Mirowedenije-Observatory-Expedition,

Which may be the reason of the reversion of the ampli- tudes of both observers: The difference of the instruments or the amplitude of the variable? This question can be resolved only by simultaneous observations by both observers at a tixed interval of time!

.406 v = c +0.025 5.45 1926 Nov. I .

J.D. 2424 ... 765.272

.280

.289 a299 .317 a333 .379 ,386 .390 .397 .403 .412 a441

766.244 . 252

.259

.266

.283

.291

.3I5

.355 770.262

. 2 7 1

771.337 .345 a359 .372 .382

Est.

e 7 v 3 f e 8 v z f e 84 7.J 14 f e 8.7 v 1.3 f e g v i f ! e g v l f a 74 v 2 4 c a 7 v 3 c ? a 7 f v z $ c? c ~ v g e ! c z v 8 e c 3) v 6 8 e c 7 v 3 e a 84 v 14 c a 7 i v 2.$ c a 8 v z c c 4 v 9 s e c ~ v g e c 44 v 54 e c 7 4 v 2ae e 1 v 9 f c 8 v z e c 8.2 v 1.8 e e 9 a v if e 9.6 v 0.4 f e 9.2 v 0.8 f e 8) v I:./:

e 9 v 1 f

m - OdO97 - 0.089 - 0.080 - 0.070 - 0.052 - 0.036. + 0.010

fo.017 i 0 . 0 2 2

+ 0.028 + 0.034 '+ 0.043 + 0.072 - 0.006 + 0.002 + 0.009 + 0.016

+ 0.041 + 0.065

+ 0.050

+ 0.033

+ O . I o j

+ 0.059 + 0.245

+ 0.'267 f'0.280 + 0.290

+ 0 . 2 j 3

Br.

14*2 I

14.79 15.08 15.20 '5,37 '5.37 4.09 3.82? 3-05? 5.92 6.39 7 . 1 0 8.83 4.63 4.09 4.36 5.68 5.92 7.56 8.98

'0.73 9.21 9.30

15.66 1 5 . 7 2

15.49 15.08 '5.37

J.D.

772 .251 .272

.282

.345 ,358 .368 .379 ,397 .402 .407 .419 .425

444 78 I .265

2424 ...

,436

785.2 34 .240

.255

.330

.363 787.327

.349

.358 ,372 .378 .389 .395

Observations. Est . @

+ od278 + 0.299 + 0.309 - 0.068 - 0.055 -0.045

-0.016 - 0.034

- 0.01 I

a 7 V . 3 6 - 0.006 a 6 v 4 c ? + 0.006 a 74 v 2 4 c +0.012

c I v y e + 0.023 c r v g e + 0.031

c 4 v 6 e! +0.054 c 6 v q e 4- 0.047

e 1.Z v i.8f +o.150 e 3 v 7 f +o.183 e 9 v 1 f -0.054 e 6 v 4 f ! -0.032

e l v 9 f -0.023 a 7 4 v 2 i c! -0.009 a 7 v 3 c - 0.003 a 7p v 24 c +0.008 a 84 v 14 c +0.014

Br.

I 5*08 75.37 15.37 15.78 15.78 15.66 15.54 5.92 4.69 3.82

4.09 5.92 5.92 8.27ci 7.33

3.27?

8.041 8.09J

11.89

13.63

8.50 10.85

15.37

10.73 4.09 3.82 4.09 4.63

Est. J.D. 2424... 788.252 a 94 v 4 c! -odoio

.258 a 8.7 v 1.3 c -0.004

.276 a 8 i v 1 4 c +0.014

.281 c I v g e ! +0.019

.317 ~ 4 4 ~ 5 9 e +o.o5 j -335 c 9 7.J 1 e + 0.073

794.242 e 8 v 2 f ! i-0.257 .251 e 9 v i f +0.266 .267 e 9 v I f +0.282

.282 e 8& v 11 f -to.297 ,293 e 8.3 v 1.7 f -t0.308 .342 e 9.2 v 0.8 f -0.083

795.292 c I v 9 e -0.014

.264 a 8 v 2 c + 0.002

.303

.310 797.238

.277 ,304

803.201 .207

.218

a 6.8 v 3.2 c a 7.7 v 2.3 c e 4 v 6.f L'7*3f . e 8.2 v 1.8 f c 1.7 v 8.3 f! e 1 i v 8 4 f v=c !

-0.003 + 0.004 to.171 + 0.210 t 0.237 - 0.029 - 0.023 -0.012

,224 a 8 1 v 14 c! --0.006 .232 a 7.6 v 2.4 c t 0 . 0 0 2

.241 a 8 i v 1 2 c + O . O I I

,246 a 9.2 v 0.8 c + 0.016 .263 v=c! : t 0.033 , 2 7 1 c 1.2 v 8.8 e +0.041

Br.

5%8! 4.74 4.36 4.63 5-92 7.56 9.68

14.79 15.37 15.37 15.08 14.96 '5.49 5.92 3.68 4.20

12.47 14.21 14.91 11.14

5.45 4.63 4.14 4.47 5.01

6.01

1 1 . 0 2

5.45ci

W. Zessewiisch.