COMESEP 2nd Year Progress Meeting

Written by Jaša Čalogović Tuesday, 29 January 2013 10:20

COMESEP meetingCOMESEP 2nd Year Progress Meeting will be organized by Hvar Observatory and take place at Zagreb Observatory from 15 to 19 April, 2013 in Zagreb, Croatia.

>> more information about COMESEP Meeting


New version of Drag-Based Model (DBM)

Written by Jaša Čalogović Friday, 25 January 2013 18:21

CME geometry plotThe purpose of the basic form of the model is to provide a prediction of the arrival time and impact speed at the Earth. Calculations are based on the assumption that the dominant force in the heliospheric dynamics of ICMEs is the magnetohydrodynamical equivalent of the aerodynamic drag. For a given set of input parameters it provides the ICME Sun-Earth transit time, the arrival time, and the impact speed.
The new version of DBM now includes the advanced DBM which provides this output for any target in the heliosphere and takes into account also the shape of ICME employing the so-called cone-geometry. Plots showing the impact speed depending on the distance from the Sun (v-R) and CME geometry are added to the model outputs. 

>> link to Drag-Based Model

XIIth Hvar Astrophysical Colloquium proceedings

Written by Jaša Čalogović Friday, 05 October 2012 10:30

HAC-XII-group-photoWe would like to remind that the deadline for submitting the manuscripts for the proceedings of 12th Hvar Astrophysical Colloquium "The Sun and Heliosphere" is November 30, 2012
The following page limits apply for the proceedings: reviews = 18 pages, invited talks = 14 pages, contributed talks  = 12 pages, posters  = 6 pages.  

Manuscripts should be prepared in LaTeX, preferably using the Cent. Eur. Astrophys. Bull. style file which is available here


Photos - XIth Hvar Astrophysical Colloquium

Written by Jaša Čalogović Tuesday, 10 July 2012 18:45

HAC-XI-group-photoPictures from XIth Hvar Astrophysical Colloquium (2.-6.7.2012) you can find under the links here:
 Photos by LOC
 Photos by participants

We would like to remind you that the deadline for submitting the manuscripts for Proceedings of XIth HAC (special volume of the Central European Astrophysical Bulletin) is October 30, 2012.


Venus transit on 6.6.2012 – Hvar solar telescope observations

Written by Jaša Čalogović Wednesday, 06 June 2012 16:37

H-alpha, Venus transitDuring the morning hours of 6.6.2012, Hvar Observatory double solar telescope was able to observe and record the last Venus transit in this century. Photospheric and chromosperic telescope were used from the sunrise (3:44 UTC) till the end of transit (4:55 UTC). Unfortunately for those who missed it, the next Venus transit will not occur until December 2117. Observer was Nikša Novak and data were processed by Jaša Čalogović.

> Short movies generated from the telescope data can be accessed here


Online talk - Can solar activity and cosmic rays save us from global warming?

Latest news

Written by Jaša Čalogović Sunday, 01 April 2012 23:02

talk calogovic_IACAll those interested in solar influences on climate and especially in the contended topic about link between the cosmic rays and clouds can now online access the talk of Jaša Čalogović held on IAC, La Laguna on 15. March 2012.

> Click here for the abstract and video of the talk


Solar irradiance, cosmic rays and cloudiness over daily timescales

Latest publications

Written by Jaša Čalogović Tuesday, 20 December 2011 00:00

thumb cloudsAlthough over centennial and greater timescales solar variability may be one of the most influential climate forcing agents, the extent to which solar activity influences climate over shorter time periods is poorly understood. If a link exists between solar activity and climate, it is likely via a mechanism connected to one (or a combination) of the following parameters: total solar irradiance (TSI), ultraviolet (UV) spectral irradiance, or the galactic cosmic ray (GCR) flux. We present an analysis based around a superposed epoch (composite) approach focusing on the largest TSI increases and decreases (the latter occurring in both the presence and absence of appreciable GCR reductions) over daily timescales...

 GRL website


Cosmic ray modulation by different types of solar wind disturbances

Latest publications

Written by Mateja Dumbovic Tuesday, 20 December 2011 00:00

SWD-CR-dumbovic-2011The amount of the galactic cosmic rays (primarily protons) that hit the Earth is greatly influenced by the solar activity. On the short time scales it can be substantially reduced by the passing of solar wind disturbances, such as interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs). The resulting short-term cosmic ray depressions are generally denoted as Forbush decreases. We present a systematic statistical study of various aspects of Forbush decreases. The analysis is based on ground-based neutron monitor data and the in-situ solar wind data recorded by the Advanced Composition Explorer (ACE) satellite and provides empirical background for physical interpretations of short-term cosmic ray modulations.

 read publication (A&A website)

First announcement - XIth Hvar Astrophysical Colloquium

Latest news

Tuesday, 01 November 2011 03:12

binary starAt the occasion of the 40th anniversary of Hvar Observatory, XIth Hvar Astrophysical Colloquium: The Most Mysterious Binaries: Significance for Astrophysics will be organized from 2. to 6. July 2012  in Town Loggia, Hvar, Croatia. The scientific sessions will include topics:  Binaries as Tests of Stellar Evolution Models, Extreme and Unusual Binaries, Rapid Phases of Binary Evolution, Be Binaries and Highest to Lowest Mass Binaries. Deadline for a regular registration is 15. March 2012 (150 EUR) where after this deadline the late registration will be charged with 200 EUR.

 first announcement
 further details & registration 


First announcement - XIIth Hvar Astrophysical Colloquium

Latest news

Tuesday, 01 November 2011 03:12

thumb sun_heliosphereAt the occasion of the 40th anniversary of Hvar Observatory, XIIth Hvar Astrophysical Colloquium: The Sun and Heliosphere will be organized from 3. to 7. September 2012  in Town Loggia, Hvar, Croatia. The scientific sessions will include following topics: The Solar Photosphere - Theory and Observations, The Chromosphere - Link between the Photosphere and Corona, Eruptive Processes, CME's and Energetic Particles, Solar-terrestrial Connection and the Heliosphere, Observing Techniques, Data Analysis and Archives.
 pdffirst announcement
 further details & registration 

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  • Solar Activity Level: LOW
    Solar Activitly level is LOW.

    2-day Flare Index (entire sun): 6.7
    X-Class Flares: 0
    M-Class Flares: 0
    C-Class Flares: 5
  • Most Active Region: NOAA 12529
    The Most Active Region is NOAA 12529.

    2-day Flare Index: 3.9
    X-Class Flares: 0
    M-Class Flares: 0
    C-Class Flares: 3

    Region Statistics for Today
    Mount Wilson Class: b
    Area: 0850
    Nummber of Spots: 19
    Flares: C1.8 (07:40)

    Region Statistics for Yesterday
    Mount Wilson Class: b
    Area: 0820
    Nummber of Spots: 16
    Flares: C1.1 (01:36) C1.0 (18:28)


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