... Tonight's Sky . ... Sky this Month . ... Star Atlas . ... stars . ... The Sky This Week: April 1 - 10 . ... Observing springtime deep-sky objects with a large telescope . ... Why do some stars appear to flash a variety of different colors when you look at them through a telescope? ... So, Earthт??s atmosphere will bend some colors from especially bright stars more so than others, which makes the source look like itт??s flashing colors. Get instant access to subscriber content on Astronomy.com! ...

... the time of observation . ... Observing the Changing Position of the Sun To Establish Cardinal Directions . ... Observations of the Sun's apparent movement across the sky and its pattern of rising and setting in the east and west horizon helped to establish the cardinal directions. ... The final stage of the Sun's return was marked by the observation that the Sun had reached its highest altitude when the full width of your mitted hand could fill the gap between the Sun and the horizon. ...

... Data Reduction FAQ > The reduced science spectrum displayed in the Reflex window appears good but when I try to plot it, it is quite different. How can I get it? ... Observing with ESO Telescopes . ... ESO-MIDAS . ... Reflex . ... ESO Data . ... ESO HST Image Galleries . ... ESO Data Access Policy . ... ESO Science Newsletter . ... ESO Annual Reports . ... Seminars at ESO Santiago . ... Seminars at ESO Garching . ... ESO Telescope Bibliography . ... Last Update: 01.04.14 ESO . ...

... We will consider the rms, (K), for observations with a receiver of system temperature, T , frequency resolution, per polarization, and total integration time per observing cycle, . ... For ``in-band'' frequency switching, the line under investigation is always in the observing band. ... Position Switching or ``Out-of-Band'' Frequency Switching: Here the line is only observed for one half of the time, with noise being present all of the time. ...

... Explanations of the Observation codes and GRT codes are available. ... V codes are for AO1 experiments W codes are for AO2 experiments VS experiment codes are VSOP Survey Observations VT Test/Calibration Observations EXPNO SOURCE FRQ Corr DOY DY: DATE UT RANGE #TEL TELESCOPES W071n J0745+10 L Mitk 6 We:Jan-06 10:00 - 17:00 6 UD SH KA AT MP HO W059e J0811+01 C Socr 7 Th:Jan-07 04:00 - 14:00 10 VLBA VS10a J0842+18 C Pent 8 Fr:Jan-08 13:00 - 18:00 6 CD HO UD SH KA MP VS11r J0909+01 C ...

... To be read in conjunction with Section 4.11 of the WFPC2 Instrument Handbook , -Version 4.0. ... 1 The second study found evidence that CTE loss for faint stars has increased with time (Whitmore, 1998). The primary observational consequence of CTE loss is that a point source at the top of the chip appears to be fainter than if observed at the bottom of the chip, due to the loss of electrons as the star is read out down the chip (see Figure 1 ). ... Last updated: 06/16/98 10:38:00 . ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

... The following charts/text are intended as tools for monitoring the Type Ia supernovae ( SNe ) event visually or photographically (utilizing telescope equipped CCD equipment).The files include: A replication of The Type Ia SNe , V- magnitude (with data point checks from other cited references)and color index (B-V) templete (to indicate a general color-related trend of the type Ia ... I believe this might help alleviate some of the problems involving the making of acceptable amateur light curves...

... 227Wink This paper containes an investigation of 91 sources which appear to be point sources when observed with the angular resolution of the 100-m telescope at 4.9 GHz, teta_a = 2.6', and which we expected to be HII regions. The basic search list was prepared from the 4.9 GHz survey of the galactic plane by Altenhoff et al. ... In the present paper we list 4.9 GHz flux densities only for sources for sources for which we present new observations. ... source structure indicated . ...

RTT150 . ... This search system is designed for generating the necessary information on series of pointings (observations of each source consist of sets of exposures with different filters and sometimes with different exposure times) for observed sources. Search results appear at the separate page as a table with the following data: . DATE - real (not evening!) observations date (in YYYY-MM-DD format); . ... Bin - minimal CCD binning mode (may vary during the observations); . ...

... Here some data observed on the 6m telescope with IFP installed in the OLD focal reducer are presented. ... Mkn 3: velocity field . ... NGC 5252: [OIII] image . ... NGC 5252 was observed 23 Feb. 1998 in the [OIII]5007 emission line with CCD TK1024 as detector. ... We observed the ionized gas velocity fields of the spiral galaxies with two purpose. ... Restored velocity field of NGC 157 in the reference frame rotating with the pattern speed overlaid on the Ha image of the galaxy . ... NGC 4100 . ...

... Triton: Neptunes Largest Moon . ... So, looking toward the Sun, extreme ultraviolet cameras onboard STEREO B were able to record a stunning movie of a lunar transit (aka solar eclipse), as the Moon tracked across the solar disk. ... Stars, Dust and Nebula in NGC 2170 . ... Visible above are red glowing emission nebulas of hydrogen, blue reflection nebulas of dust, dark absorption nebulas of dust, and the stars that formed from them. ... APOD: 2007 February 24- X rays and the Eagle Nebula . ...

ATMoB "Double Star Award " Guidelines Purpose: To promote observing among the membership of the Amateur Telescope Makers of Boston ­ in particular, double, triple, and multiple stars. Introduction: Double, triple, and multiple stars are the "Rodney Dangerfields" of the night sky. ... W hile they can be observed under a variety of sky conditions, double stars ­ especially close ones ­ are best viewed on nights when the seeing is steady. ... The direction from a star to Polaris is north. ...

... Exposure Time Calculator (ETC) . ... ESO - Public Surveys . ... the recommended values to use for DIT, . ... Detector on-chip integration (DIT): seconds. to your chosen value - a separate page gives recommended values to use for DIT - for modes 1 and 2 below you may wish to start with the maximum recommended values as these will minimize the effect of read noise (a total object exposure of Y secs with DIT=X secs will produce Y/X lots of read noise) and give you a lower limit on the time needed. ...

Observatory, 125, 23­24, 2005 NEGATIVE REPORT OF OCCULTATION BY THE D-TYPE ASTEROID (773) IRMINTRAUD By Apostolos Christou and Mark Bailey Armagh Observatory An unusual negative observation is reported of the predicted occultation of the star HIP 186 by (773) Irmintraud on the morning of 21 July 2004. ... This provides a constraint on the asteroid's position at the time of the event. ... References (1) R. L. Millis, D. W. Dunham, "Precise measurements of asteroid sizes and shapes from occultations". ...

... The J, H and K bands are characterized by a bright background, such a background is mainly due to the emission of atmospheric lines and of thermal radiation. ... If the source cover a large fraction of the slit, spectra off-source must be observed to adequately sample the sky background. ... The on chip integration time (time spent in each position of the slit) must not exceed 40 seconds in J and H bands and 60 seconds in K band. ... We suggest a sequence of 10 for each elementary integration time. ...

M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Color CCD Picture Very Deep M57 Image . ... M81 image More About M81 M81 Supernova Ultraviolet Image of M81 More about Ultraviolet Imaging . M82 image More About M82 M82 False Color M82 True Color . ...

... Observing . ... Home Education Workshops at Adorama Astronomy Workshop: Observing Variable Stars from the City ? February 15, 2015 . ... Beyond New York City . ... Observing Resources for Amateur Astronomers - Part 1: Beginning Observers . ... A History of the First Forty Years of the Amateur Astronomers Association . ... Presented by€а Adorama €аFor the Amateur Astronomers Association of New York . ... 2016 Amateur Astronomers Association of New York Designed by Press Customizr Powered by . ...

Follow-up astrometry and recoveries are made with the ANU 40 inch (1.0-m) f/8 reflector at Siding Spring Observatory (IAU code 413). ... A routine follow-up of 2003 WY153 on 2003 Dec 15 became much more than routine when a faint object with unusual motion vector was found close to the target asteroid. ... During routine astrometry with the 1.0-m to improve the orbit of the Apollo asteroid 2004 CB, the asteroid was found on March 30 to have a short tail! ... Siding Spring Survey Main Page . ...