DO Dra

2022-05-14T09:37:10+00:0012 May 2022|News, Variable Star|

AAVSO “Alert Notice 753: Monitoring requested for seven intermediate polars” – DO Dra (also known as YY Dra) is on the list, it’s circumpolar and easy from here.

“Photometry (V, CV) of the targets in the table below is requested. DSLR green and visual observations are welcome to supplement the light curves. The cadence requested is every other night, as weather permits, and “about one hour of coverage per night (enough to catch a few spin cycles of the white dwarf). If a source is found to be in a low state, then we request longer coverage and nightly cadence. SNR>>10 is ideal…”

Photometry (V, CV) of the targets in the table below is requested. DSLR green and visual observations are welcome to supplement the light curves. The cadence requested is every other night, as weather permits, and “about one hour of coverage per night (enough to catch a few spin cycles of the white dwarf). If a source is found to be in a low state, then we request longer coverage and nightly cadence. SNR>>10 is ideal…”

Covington adds: “These systems show periodic variability on the spin period of the WD, usually on order of ~10 minutes. So, shorter exposure times are needed so the spin variability isn’t washed out. Previous AAVSO observations of these sources have had exposure times <60s, which is ideal. Also, accurate time tagging of the observations is required, so we can measure periodicities!”

Thought I’d give it a go for 1 hour. Uploaded to AAVSO and BAA databases.

Object IDDO Dra
Typical/high state mag. 15.0 – 15.5 V
Range: 10.0 – 17.2 V
Details23:00 – 23:59 UT
Telescope250mm f4.8 Newtonian
CameraAtik 460ex @-10°C
FiltersV photometric
Exposure(s)70 x 60s
dfb
CaptureNINA
ProcessingASTAP

An Intermediate Polar (also called a DQ Herculis Star) is a type of cataclysmic variable binary star system with a white dwarf and a cool main-sequence secondary star. In most cataclysmic variables, matter from the companion star is gravitationally stripped by the compact star and forms an accretion disk around it. In intermediate polar systems, the same general scenario applies except that the inner disk is disrupted by the magnetic field of the white dwarf.

The name “intermediate polar” is derived from the strength of the white dwarf’s magnetic field, which is between that of non-magnetic cataclysmic variable systems and strongly magnetic systems. Non-magnetic systems exhibit full accretion disks, while strongly magnetic systems (called polars or AM Herculis systems) exhibit only accretion streams which directly impact the white dwarf’s magnetosphere.

Wikipedia

V1297 Cas eclipsing binary

2022-05-12T14:53:07+00:007 February 2022|Eclipsing Binary, News, Other, Variable Star|

No predictions for transit times for this one so trial and error. Sadly missed both peaks and dips.

Object IDV1297 Cas
Eclipsing binary in Cassiopeia
Details2022-02-06
19:34 – 23:27 UT
Telescope250mm f4.8 Newtonian
Photometric V filter
CameraAtik 460EX @-10°C
Exposure(s)620 x 15s
darks, flats, bias
CaptureNINA
ProcessingAstroImageJ
V1297 apertures

NR CAM eclipsing binary

2022-05-12T14:53:16+00:0028 January 2022|Eclipsing Binary, News, Other, Variable Star|

Got both secondary and primary transits before cloud came in but had hoped to get both peaks to see if asymmetric or not which might indicate star spots. Primary transit is deeper than the secondary.

Wrote a How-To article on the ASE website about this: How to record an eclipsing binary transit light curve

Object IDNR CAM
Eclipsing binary in Camelopardalis
Details2022-01-27
18:01 – 22:22 UT
Telescope250mm f4.8 Newtonian
Photometric V filter
CameraAtik 460EX @-10°C
Exposure(s)476 x 25s
darks, flats, bias
CaptureNINA
ProcessingAstroImageJ

Finder chart and data:
AAVSO — Variable Star Plotter

V523 Cas eclipsing binary

2022-05-12T14:53:30+00:0025 January 2022|Eclipsing Binary, News, Other, Variable Star|

Cloud stopped play so caught the primary transit but not the secondary. Will try this one again since it transits so fast.

Object IDV523 Cas
Eclipsing binary star
Details2022-01-24
21:44 – 22:58 UT
Telescope250mm f4.8 Newtonian
CameraAtik 460EX @-10°C
Photometric R filter
Exposure(s)137 x 25s
darks, flats, bias
CaptureNINA
ProcessingAstroImageJ

AAVSO — Variable Star Plotter

PZ UMa eclipsing binary

2022-01-28T09:09:25+00:0018 January 2022|Eclipsing Binary, News, Other, Variable Star|

Thought I’d try to catch an eclipsing binary transit since no obvious exoplanet ones to do for last night. First processed in HOPS, since that’s what I know, but that obviously wants to map an exoplanet transit onto the data. Finally processed in AstroImageJ, which charted it quite well.

Object IDPZ UMa
Details2022-01-17
21:18 – 00:12 UT
Telescope250mm f4.8 Newtonian
R Photomeric filter
CameraAtik 460EX @-10°C
Exposure(s)155 x 60s
darks, flats, bias
CaptureNINA
ProcessingAstroImageJ