longmont astronomical society newsletter · alignment points, so adjust the alignment point size....

April 2016

Longmont Astronomical

Society Newsletter Image Credit: Chris Fauble

Copyright © April 2016. All rights reserved. Longmont Astronomical Society.

Next LAS Meeting April 21st

“Time-Domain Astronomy and Las

Cumbres Observatory Global

Telescope” by Dr. Tim Brown

Abstract:

Astronomer's view of the universe is changing from seeing the sky as unchanging "wallpaper", to a dynamic picture in which everything changes, all the time. More, we are realizing that the ways in which things change often give us clues to the physics of astronomical objects that we could not obtain otherwise. The buzzword for this view is "time-domain astronomy", and its hardware manifestations range from the 8-meter Large Synoptic Survey Telescope (LSST), down through the Kepler Mission's 1-meter space telescope, to 30-cm backyard telescopes run by enthusiastic amateurs. In the middle of this range is Las Cumbres Observatory Global Telescope (LCOGT), so far the only observatory dedicated exclusively to the general field of time-domain astronomy, and equipped to observe many kinds of time-varying phenomena. LCOGT operates a worldwide network of telescopes with apertures from 40 cm to 2 meters, working on programs that include extrasolar planets, supernovae, near Earth asteroids, and active galactic nuclei. I will briefly review the history of observational astronomy (and show that observing the time domain is getting back to old roots), and then describe LCOGT's origins and facilities, ending with some highlights of the science that LCOGT scientists are now doing.

Location: The meeting will be at the IHOP Restaurant, 2040 Ken Pratt Boulevard, Longmont. Please join us for coffee, dinner, or just desert around 6 pm; The general meeting and presentation will begin at 7 pm.

Upcoming Events

April 15th 8 pm Imagine Charter School 6th

Grade Star Party, 1573 Twilight Ave,

Firestone, CO.

April 16th 8:30 pm Majestic View Nature Center 7030 Garrison St, Arvada, CO

April 21st 7 pm LAS Meeting "Time-Domain Astronomy and Las Cumbres Observatory Global Telescope" by Dr. Tim Brown at IHop Restaurant, 2040 Ken Pratt Boulevard, Longmont.

May 19th 2016 - 7 pm LAS Meeting “NASA’s Messenger Mission” by Dr. Dan Baker at IHOP Restaurant, 2040 Ken Pratt Boulevard, Longmont.

https://www.longmontastro.org/meetings/las-meeting-march-17-pluto-pugnacious-planet-dr-fran-bagenal




Copyright © March 2016. All rights reserved. Longmont Astronomical Society. Page 2

April Celestial Highlights

Moon

New moon: April 6th 5:52 am First quarter: April 13th 10:01 pm Full moon: April 21st 11:25 pm Third quarter: April 29th 9:30 pm

Mercury

Mercury is visible in the evening sky from

April 2nd throughout the rest of the

month. It begins the month at -1.5

magnitude in brightness and slowly fades

to magnitude +2.9 by the end of the

month. It may be viewed about an hour

after sunset very low in the west.

Venus

Venus is not visible this month.

Mars

Mars begins the month with an apparent

brightness of -0.5 and is 12 arc sec across.

At the end of the month it will be

magnitude -1.5 and will be 16 arc sec

across. Mars opposition will be on May

22nd.

Jupiter

Jupiter opposition was on March 8 but it

still is fabulous month to view Jupiter. It is

up high and convenient to view in the

evenings. Shadows from Jupiter moons Io

and Europa are visible on the disk at the

same this month April 5 from 2:18 am to

3:41 am. Both Io and Europa shadows

may be seen transiting from 3:37 am to

4:19 am. So from 3:37 to 3:41 am you can

see both moons and their shadows

transiting.

Assuming the longitude of the Great Red

Spot is 241.3° it may be seen at mid

transit at the following times this month:

Apr 1 3:57 am alt 23° Apr 2 11:49 pm alt 58° Apr 5 1:27 am alt 47° Apr 5 9:18 pm alt 51° Apr 7 3:05 am alt 28° Apr 7 10:56 pm alt 59° Apr 10 12:35 am alt 51° Apr 10 8:26 pm alt 46° Apr 12 10:04 pm alt 58° Apr 14 11:43 pm alt 55° Apr 16 1:21 am alt 40°


Apr 17 9:12 pm alt 56° Apr 18 2:59 am alt 20° Apr 22 12:29 am alt 45° Apr 23 2:08 am alt 26° Apr 24 9:59 pm alt 59° Apr 26 11:38 pm alt 50° Apr 29 9:08 pm alt 59° May 1 10:46 pm alt 54°

Saturn

Saturn is in lower part of the constellation

Ophiuchus. It is magnitude +0.4 in

brightness as month begins and +0.2 on

April 30. Its disk increases from 17 arc sec

across to 18 arc sec this month.

Uranus

Uranus reappears in the morning sky after

the 24th. It is in the constellation Pisces; it

is magnitude +5.9 in brightness and its

disk is 3.3 arc sec across.

Neptune

Neptune is visible low in the morning sky

in constellation Aquarius. It is magnitude

7.9 and 2.2 arc sec across.

Meteor Showers

The Lyrids meteor shower peaks on April

21st but since it is also full moon only the

brightest will be visible.

Comets

Comet

252P

(Linear)

is visible

this

month

in

constell

ation

Ophiuch

us. It is

magnitude 5.7 in brightness and coma is

5.7 arc min across. (Image credit Gary

Garzone).


Comet C/2013 X1 (PANSTARRS) is visible

this month in constellation Pisces. It is

fairly low and dropping into evening

twilight as the month progresses. It begins

the month at magnitude 8.6 and

brightens to 8.3 by months end. The coma

diameter decreases from 4.4 arc min to

2.8 arc min.

Comet C/2014 S2 (PANNSTARRS) is visible

in the constellation Ursa Major. It is

magnitude 9.8 in brightness and its coma

is 2 arc min across.

Comet C/2013 US10 (Catalina) is visible in

the constellation Camelopardalis. It

moves into constellation Perseus on the

16th. As the month begins it is magnitude

8.9 in brightness and will fade to

magnitude 10.7 by month end. The coma

is decreases from 4.4 arc min to 2.8 arc

min in diameter. (Image Credit Paul

Robinson).


Overhead Sky at 9:30 pm March 15

It is a springtime galaxy bonanza in

the eastern sky this month. The

constellations Virgo, Coma Berenices,

and Canes Venatici provide a rich

assortment of the best and brightest.

Messier 51 in Ursa Major is high up

and always worth a look. Jupiter is

now center stage for convenient

early evening viewing.

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Overhead Sky at 8:30 pm April 15

It is time to take a farewell view of

Messier 42, the Great Orion Nebula,

before it disappears in the evening

twilight next month.

Be sure to check out Mercury about

45 minutes to an hour after sunset.

Gemini is still high so aim your small

scope or binoculars to open cluster

M35. Use one of your larger scopes

to view NGC2392, the Eskimo nebula

also in Gemini.


LAS March 17th meeting at IHop

The meeting began at 7 pm with

announcement of the agenda for the

evening and upcoming star parties.

The guest speaker was Dr. Fran Bagenal

with the Laboratory for Atmospheric and

Space Physics (LASP) at the University of

Colorado. Her presentation was “Pluto

the Pugnacious Planet”. Fran has been a

member of New Horizons team since the

project was first proposed to NASA over

15 years ago. She reviewed the mission

highlights as it progressed in its journey to

Pluto. She discussed some of the stunning

images that have received and discoveries

made by the team that were published a

week before in Science Magazine. Pluto’s

upper atmosphere is much colder and

way more compact than models

predicted. (See

Image credit:

NASA/JHUIAPL/SwRI

o


http://science.sciencemag.org/content/3

51/6279/aad8866). Pluto’s four small

moons rotate rapidly and their obliquities

suggest that their shapes were caused by

collisions. (See


51/6279/aae0030). Particle instruments

aboard New Horizons indicate that the

interaction region sunward of Pluto is

quite small around 6 planet radii; beyond

Pluto it is about 400 planet radii. (See


51/6279/aad9045 ). New Horizons

observations of Pluto indicated regionally

diverse colors and compositions. (See


51/6279/aad9189 ). Surprisingly Pluto’s

surface geology is active and is centered

on a vast basin of thick volatile,

convective ices. ( See


51/6279/1284 ).

Following Fran’s presentation we had a

short business meeting. Mike Fellows

gave the monthly financial report. Vern

Raben did an update on the Library

Telescope Project – two telescope kits

were delivered to the Louisville Public

Library on March 19.

Planetary Image Processing

Vern provided a brief tutorial of using the

AutoStakkert application to align and

stack planetary images. The application is

available for download from

http://www.autostakkert.com/wp/downl

oad/

Just extract the zip file to a directory on your machine. Navigate to that folder with Windows Explorer and then double click on the Autostakkert application to run it. The application will start and you first click on the “1) Open” button toward the upper left. After you navigate to the folder where you stored your videos, select the video files you wish to stack. You may select multiple files and it will stack them all. The files selected should be at the same magnification, exposures, etc.

Next set the following for “Image Stabilization”:

For planets select “Planet COG”.

For lunar and solar in which the full disk may not be see select “Surface” otherwise select “Edge”.

If planet fits entirely

within the image but is

not completely visible such as before opposition when a portion of the disk is dark– uncheck the

http://science.sciencemag.org/content/351/6279/aad8866


http://science.sciencemag.org/content/351/6279/aae0030

http://science.sciencemag.org/content/351/6279/aae0030





http://science.sciencemag.org/content/351/6279/1284

http://science.sciencemag.org/content/351/6279/1284

http://www.autostakkert.com/wp/download/

http://www.autostakkert.com/wp/download/


portion of the disk that is not visible.

Next click the “Analyze” button.

The quality of the frames in the video will be analyzed an then sorted. You may scroll through the frames by moving slider on top of the window at the right. The best quality frames are on the left so that will be used for the reference image.

Now you need to set the alignment points which is done using window on the right. Adjust the “Set Size” slider at top so entire planet is covered (usually not necessary to change). I try to end up with 80 to about 100 alignment points, so adjust the alignment point size. Other people use only a few dozen. I usually set AP size to 25 for small relative size planet in the image, 50 for Jupiter

with 2X barlow. If you end up with an image where “stitches” from these small alignment windows show, you just need to decrease the number of alignment points to correct.

Click on the “Place Aps in Grid” button. You’ll end up with something like this:


Finally, move the “Alignment points”

window out of the way, and click the “3)

Stack” button.

The AutoStakkert program will then

process each video and create a stacked

image for each.

A new directory will be created under your video images source directory, named something like “AS_???_Multi”.

The directory contains the aligned an stacked images which you may then sharpen with an application such as Registax6. I’ll cover Registax6 in detail in a future tutorial.


Image credit: Gary Garzone

Image credit: Gary Garzone


Image Credit: Vern Raben


Image Credit:

Comet 252P by Gary Garzone


Image Credit:

David Elmore

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