Colourful variables

 

You can find here colour images of colourful variable stars made from DSS-2 three colour plates or Brno CCD ST-7 images filtered mostly by VRI, brighter stars also by B. Software used: IRAF's task imalign and Photoshop.

All pictures are public domain but I would appreciate letting me known (pejcha@astro.sci.muni.cz) if you use it somewhere.

Unmistakeably reddish V838 Mon is still bright in near-infrared two years after its puzzling brightening. Images taken on 22nd January 2004 (3x30s R and I and 3x120s V).

Beatiful planetary nebula M27. The strange green colour is caused by strong H-alpha emission, which has fallen to R filter (i.e. green channel). The nebula is barely visible in other filters. Due to strange spectrum, exposure times were simple: 5x30s in VRI. Note also the very red object on the upper right from the center of M27 - it is Goldilock's variable star discovered by Leoš Ondra in 1991. Some photometry has been done by Rudolf Novák and Arne Henden, but more than ten years after discovery the star still lacks GCVS designation.

Great globular M4 in the Scorpius. It was imaged just above observatory's dome:-) Exposure times were rather short to prevent saturating of all objects: 5x5s in I, 5x6s in R and 4x30s in V.

Well-known symbiotic binary YY Her (arrows). Note also the object near the bottom of the frame, which is redder than YY Her itself. (5x30s in R and I and 5x60s in V).

Suspected symbiotic binary V503 Her. (5x30s in R and I, 5x60s in V).

Two variable stars on a single frame, SX UMa (the rightmost star of the triangle of very bright stars), bright RRc type star, and BG UMa (the uppermost star of the triangle), ellipsoidal variable with well pronounced gravity darkening. (5x60s in V and 5x30s in R and I).

Symbiotic variable star StHa 55 (bright orange star in upper center). (10x60s in V and 5x30s in R and I).

Symbiotic variable star StHa 149 (bright red star in right center). (3x60s in V and 4x30s in R and I).

Mira type variable RR Boo (the reddest star in the left part of the image). Field was imaged due to some nearby standards. (5x60s in V, 5x30s in R and I).

Symbiotic variable star Hen 2-468 (position indicated by arrows). (4x60s in V, 4x30s in R and I).

RR Lyr type variable star AE Boo (brightest star in the right part of the image. Other stars in this field constitute GSPC sequence P441. (5x60s in V and 5x30s in R and I).

Nova Oph 2002 aka V2540 Oph (bright blue star near the center) on 30th March 2002. Imaged by O. Pejcha in V (4x30s) and R and I (each 4x20s). V2540 Oph exhibits strong oscillations.

Everything was cloudy except a portion of sky around Orion, so gorgeous M42 was imaged (5x30s V, 5x13s RI, frames by O. Pejcha).

Same as above but with non-linear scaling of pixels to make Trapezium more visible.

V838 Mon in its second outburst as catched on VRI frames made by P. Sobotka and O. Pejcha. It is the brightest star in the field.
Hypernova SN 2002ap near spiral galaxy M74 (5x50s exposures in each VRI passbands; P. Sobotka, O. Pejcha). Spiral arms are not seen clearly because of low exposures. I am planning to take and stack more images. SN 2002ap is the slightly bluish star near the lower right corner.
Globular cluster M13 (39x60s exposures in each VRI passbands taken by R. Novak with 60 cm Masaryk University telescope for the calibration purposes.
Super soft X-ray source QR And (BRI images by P. Sobotka). QR And is the bluish object slightly left from the center.
Galaxy NGC 4194 also known as Medusa. As its name resembles something else, a colourful portrait from DSS images has been made to show what it really is :-)
Spiral galaxy NGC 6701 (DSS plates) close to RR Lyr star DD Draconis. Blurred colours are due to different scales of DSS images. I didn't know how to use IRAF in that times.
Remarkable Mira star AY Draconis catched on DSS plates.
AY Draconis near minimum (16.5 mag in V) on VRI images of P. Sobotka. Note that 420s exposure in V band had to be used to measure the star with 0.2 mag error :-)
SS Cyg type variable SS Cyg on images by P. Sobotka. It is the bluish star near the center of the frame.
Semiregular variable star WZ Cam on DSS plates. Some satellite or meteor is present on the infrared plate.
Suspected unique symbiotic binary V627 Cas possibly harboring post asymptotic giant branch star on DSS plates. It is the red star in the very center.
V627 Cas again, but on CCD frames by P. Sobotka (5x50s in V, 5x15s in R and 5x10s in I). Note also the very faint and red (I = 13.68, R = 15.59, V < 16.5) object just left from V627 Cas, which is seen also on the DSS image above. 
Semiregular variable star WZ Cas and its blue companion (DSS). I'd suggest looking on them through 10 inch scope, it is much better.
Neglected (and interesting!) semiregular variable AD Cep (DSS). You can see its actual light curve here.
Carbon semiregular variable V2037 Cyg (DSS).
Semiregular variable V927 Cyg. It seems that the GCVS period for this star is wrong.
Carbon Mira V335 Vul, possible symbiotic binary (images by P. Sobotka and O. Pejcha, (5x70s in V, 5x40s in R and 5x30s in I). V335 Vul is located somewhat left from the center of the image and is slightly red. Colours on this picture are somewhat strange, but I don't know why.

Made by Ondrej Pejcha. Last update on 09. 04. 2002. If you find any of these pics interesting, let me know.