maravelias.info

Only on the second day of my arrival in Chile (Jan 13, 2017) I found myself traveling from Valparaiso to Santiago to go to the Universidad Catolica Observatory (long title: Pontificia Universidad Católica de Chile), for spectroscopic observations (of bright Be stars).

Just in case you do not know where you are.

It is located about 50-60km from Santiago at an altitude of 1450m (and within the property of Hacienda Santa Martina – a private resort), so not in the darkest skies of Chile. It is a small facility which houses basically 2 telescopes, an instrument room, a control room, a small museum, a medium-sized seminar rooms, and a tiny kitchen with solely one bed to sleep. Practically people go overnight from Santiago to observe.

The front side of the UC Observatory.

The telescopes operating during the night (and… that’s why the extra noise in the photo!).

The main dome houses two telescopes, the ESO 50cm and the Tololo 40cm, and the main instrument is an echelle spectrograph (PUCHEROS) with a good outcome given the instrument and sight restrictions (see publications).

The telescopes inside the dome: the ESO 50cm in front and the Tololo 40cm in the back.

The ESO 50cm.

The ESO telescopes and part of the weight balance system.

The Tololo 40cm telescope, along with some accessories.

We came from Valparaiso for only one night of observations, so the dedication is more than obvious.

As I was not directly involved with the observations I had time to play around with my cameras. This resulted in this time-lapse video from inside the dome, that shows how the ESO telescope is slewing from one target to the next after each exposure. [Some details: GoPro 4 silver, set at 10s exposure, and running from 22:25:34 (Jan 13, 2017) up to 00:31:18 (Jan 14), video @25fps – edited with Blender.]

However, I haven’t been fortunate enough to go to the big toys yet, and I hope that this will change in the near future (not much time is left anyways…).

On Wednesday, May 11, I gave a talk at Tartu Observatory (Estonia), where I am spending a few weeks as a visitor.
Of course this is by no means something extraordinary. However, it is interesting that they could record the talk so it is available for others to see (or, most probable, for my own use).

So, the link is here:
Grigoris Maravelias: “The circumstellar environment of B[e] Supergiants – disks or rings?”

The circumstellar environment of B[e] Supergiants – disks or rings?

Massive stars affect strongly their environment through their intense stellar winds, which transfer momentum and energy to the interstellar medium and enrich it with chemically processed material as they evolve. This interaction becomes substantial in short-lived transition phases of massive stars (e.g. B[e] Supergiants, Luminous Blue Variables, Yellow Hypergiants) in which mass-loss is more enhanced and usually eruptive. However, these phases are not well-understood, such as the lack of B[e] Supergiants predicted from stellar evolution theory. In order to improve our knowledge for the particular class of B[e] Supergiants we have initiated a campaign to study them with high-resolution optical and near-infrared spectroscopy. This tool allow us to investigate their complex circumstellar environment, consisting of a combination of atomic, molecular and dust regions of different temperatures and densities. We use the strategic [OI] and [CaII] emission lines, and the CO bandheads to probe the structure and the kinematics of their formation regions. We find that these emission lines form either in a single or in multiple equatorial rings, a probable result of previous mass-loss events.

Initial Source: Tartu Observtory / seminars

I was disturbed to notice numerous horizontal lines in the video of my meteor camera (see the MetRec image). At the beginning I was afraid that this was due to the fact that the camera was powered in daylight (even with the possibility that the Sun passed through the fov!).

I asked around to find what was wrong. Fortunately, many people responded to my plea! Most refer to noise of power supply material, like bad connection with the socket, poor power supply, loose wiring, or even grounding issues.

On the contrary Tassos K. told me that this is probable due to the loose connection of the video cable than by any electric device. Indeed when the video cable connection at the pc was checked these lines disappeared.

So, I hope that this was the problem, although I will keep an eye to the power issues also!

UPDATED on 20/Nov/2013
After all it was indeed a grounding issue! The last time I opened the case for the camera I put the ground of the power supply for the case onto the thermal base where the camera is placed (see the green cable higklighted in the red region). After re-placing this cable the camera works without any more lines!

Project

The Perseids 2010 have served as a great opportunity to experiment with video recording of meteors.

A DMK camera (DMK 21AF04.AS, The Imaging Source) equipped with a CCTV 2.8mm lens and UFO Capture v2.22 were used.

First Results:

In total, the camera worked for 17 nights recording 32 meteors (mainly Perseids).

Initially the exposure time of each frame was set (through the IC Capture program, provided with DMK cameras) at 1/30 s but only the brightest stars down to 1mag were visible making the orientation of the camera and the identification of the field a very demanding task. In order to make this task easier, without losing the video functionality, the final exposure time was selected to 1/5 s and stars up to 2-2.5 could be identified in the field.

Examples (meteors identified visually as Perseids) :

Meteor’s path and velocity estimation:

Above an image of another, visually identified, Perseid and below its equivalent “map”.

The “map” is an image of the changes in the field-of-view (fov). The blue points are constant light sources (mostly stars, but also other sources like artificial lights, light pollution, etc), which are “mapped” and create a mask. This mask is, subsequently, subtracted from each frame in order to highlight only the real changes in the fov shown as red points. A meteor can be identified as a linear series of red points.

So, in this case the meteor’s path is obvious as a red “line” with breaks due to the exposure time of each frame. From the known angular distance of beta and gamma Cygni, equivalent to 16.24 degrees, the scale of the image is determined to 0.1 degrees/pixel. So, the meteor’s path is estimated to 214±4 pixels which equals to 21.4±0.4 degrees. In order to determine the velocity only the central path of the meteor is estimated (68±4 pixels, which equals to 6.8±0.4 degrees), as only this part is in between 3 consecutive frames and its time duration equals to the exposure duration (1/5 s). Thus, the minimum velocity is estimated at 34±2 degrees/s (as seen on the sky).

Outcome:

Although the sensitivity is not great, as this system’s limiting magnitude is 2 – 2.5 mag, the recording of bright meteors may be of some use (especially for fireballs), so the system could provide valuable results. But further use was never achieved as the camera was returned to the owner (under loan from J.-M. Strikis).

System Configuration:

The DMK camera was a firewire camera so a PCI firewire card was used to connect the camera to the pc.

1. install the camera’s driver for the pc (link)

2. install IC Capture (link of trial version) – necessary to adjust camera’s parameters

After these the camera should work.

3. focus camera

4. setting UFO Capture v2 (link – trial mode of 30 days with full functionality) – [Apostolos Christou, Grigoris Maravelias, Vagelis Tsamis, “Meteors and how to observe them”, Workshop notes (in Greek), 5th Panhellenic Meeting Amateur Astronomers, Mt. Parnonas, Greece, 2010]

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Quickstarting UFOCapture v2:

1. Double-click “UFO” icon. You now see four tabs: “Input”, “Operation”, “Profile”,

2. “DB”

Check that Detect Size= 2 (above the viewer, when you hit the “Live” Tab on the right).

Then go through the four tabs on the left as follows:

On “Input”:

– Select appropriate “Video” stream, eg “Hi-Speed USB DVD”

– Check that the settings are as follows

Size=640×480, Codec=AVI,fps=25

Head=35, Tail=35, Diff=1

Min(frm)=3, Max(sec)=8, EXsize=50

Detect Level Noise Tracking: Tick.

DLratio= 115, MinDL=5, MinL-N=2

Scintillation Mask: Tick.

SMLevel=107, SMSpeed=2, SMSize=3

Superimpose: on: tick, m: tick, UTC: ticked.

On “Operation”:

Snapshot, Map bmp: tick. Detect Schedule (1 of 2; tick or untick as appropriate): eg 17:30 – 07:00

Minimum Free Space: eg 1000MB. Stop: tick. Beep at Capture Start (tick or untick as appropriate).

On “Profile”

Camera ID= MO

Camera Name= WATEC902DM2S

Lens Name= COMPUTAR8MM

Interlace: tick

On “DB”

DB dir = /xxx/yyy (do >not< type it in; rather, click on button to the right and select it from the list; need to create directory *before* linking to it).

pm/am per day: tick.

Finally, press “Live” and then “Detect”.

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You may need to play around with the parameters in order to obtain consistent records. In the DMK case what was needed [thanks to Apostolos Christou] was to change only the scintillation mask level, from 107 for Watec to 130 for DMK.

A video made for the Astrophysics group of Crete, presenting the activities of the group (in Greek language only).