The SPIRIT Sky in August

The Milky Way Overhead
By mid-month, the centre of the Milky way will be directly over head by mid-evening. While you really need a dark sky site to appreciate the beauty of Milky Way, SPIRIT can be used to image the seemingly endless number of star clusters and nebulae which populate the area within and near the galactic plane. Unlike deep space objects such as galaxies, all of these targets exist within our home galaxy. Use Stellarium to zoom in on the region around M 20 and you will have several dozen objects to choose from.

August also represents a rare window to image both of the great southern globular clusters, NGC 5139, and NGC 104. To do so you will need to image NGC 5139 early in the evening, as by mid-month it is low in the south western sky. By comparison, NGC 104 is only just rising in the south east, and does not reach imaging altitude until after 10:30pm.

August provides the second ‘perfect month’ to image the Sagittarius nebulae mentioned in last month’s instalment. Advanced users may consider creating a mosaic of several adjacent fields, as most of these targets extend well beyond the field of view of the SPIRIT telescopes. Patience, and good image acquisition and processing skills are required, as well as some luck – August being one of the worst months of the year at providing weather conducive to astronomy.

A Planetary Conjunction
Although not a viable target for SPIRIT, Mars will meet up with Saturn for a stunning conjunction in August 2012. Don’t forget to walk outside and look west early in the evening to see these two paired together. They will be closest on August 15.

Blue Moon
August 2012 provides the rare occurrence of two full moons in one month. Known as a “Blue Moon” due to its rarity (as in the expression, “once in a blue moon”) it will be full on August 2nd and August 31st, so deep sky imaging is best undertaken between August 10 and August 24.

The Perth night sky Facing south at 7:30 pm on August 15.
(click on image to enlarge)

August-Chart

The SPIRIT Sky in July

Rise of the Globular Clusters
With the centre of the Milky Way galaxy rising, July marks the time of year when globular clusters come into their own. The brighter ones include those with Messier numbers, such as M4, M5, M9, and M10. Stellarium and other planetarium programs will reveal a dozen or so nicely placed bright globular clusters high in the eastern sky in the early evening.

July represents the last chance you have to acquire good images of the brighter Virgo and surrounding galaxies, such as M 104 and M 83 which are now past the meridian in the west. Be sure to image these early in the evening while perhaps waiting for the the bright Milky Way globular clusters to rise higher in the east.

Pluto
For those with bookings later in the evening, why not try imaging Pluto? A 30 second image will easily capture the faint dwarf planet, but you will need to revisit Pluto a few nights later in order to detect movement of the planet through what will be a dense field of stars. Pluto is well within the Sagittarius region of the Milky Way this month.

Nebulae
Winter marks the time of year when clear nights are most often used to acquire images of the bright Sagittarius nebulae: M16 (The Eagle Nebula), M17 (The Omega Nebula), M8 (The Lagoon Nebula) and M20 (The Trifid Nebula). All four will be virtually overhead by 10:30pm mid-month, and present an excellent opportunity to start gathering colour series data if you intend to create colour images. The H-a filter available on SPIRIT I will reveal much more detail in these hydrogen-rich emission nebulae, and can be used effectively during times of bright moon.

Speaking of the Moon, It will be full on July 4th, so the best times to image faint objects will be between July 11th and July 26th.

The Perth night sky Facing south at 7:30 pm on July 15.
(click on image to enlarge)

July-Chart

The SPIRIT sky in June

Last chance to image the great galaxy clusters for 2012
Although now moving westwards, galaxy-rich areas surrounding the constellation of Virgo still dominate the early evening sky, with Virgo directly overhead just after sunset.

The Sombrero galaxy (M 104) and the Sculptor galaxy (M 83) are highly recommended targets for those using SPIRIT to image galaxies for the first time. The fascinating radio galaxy Centaurus A (NGC 5128), together with the edge-on spiral galaxy NGC 4945, are also worthy early evening targets. East of the meridian, with plenty of time to spare, is another bright spiral galaxy: NGC 6744. Stellarium and other planetarium programs provide plenty of options for those wishing a last chance to image galaxies at this time of year.

Like May, June is a good time of the year for imaging NGC 5139, the great Omega Centauri globular cluster. It is high in the southern sky in the early evening and can be easily imaged using exposures less than 20 seconds.

While in the south, you may want to pay a visit to the Jewel Box cluster (NGC 4755). Exposures of less than 10 seconds through red, green and blue filters will provide more advanced users with enough data to create a colour image of this bright open cluster.

The hydrogen-rich nebula Eta Carina (NGC 3372) is just past the meridian and moving westwards early in the evening. It’s your last chance to image this bright region before it disappears for the year.

For those with late bookings (11:30 pm and later), consider being the first for the 2012 season to image the bright Sagittarius nebulae. They include M 16, M 17, the Trifid nebula (M 20) and the Lagoon nebula (M 8). The H-a filter on SPIRIT I will reveal a wealth of detail in these bright emission nebulae.

Planets
Saturn dominates Virgo, and although the SPIRIT telescopes are not optimised for planetary imaging, a filtered exposure of less than 5 seconds will reveal its unusual shape and some of Saturn’s brighter moons. Mars is the bright red object in the north west. Don’t forget to wander outside in the early evening to view Mars and Saturn high in the evening sky.

With the approach of winter and the centre of the Milky Way rising, now is also the time of the year to consider imaging globular clusters. More on these next month.

The Moon
The Moon is full on June 4th, so the best dates to image deep-sky objects fall between June 11th and June 27th.

The Perth night sky facing south at 7:30 pm on June 15
(click on image to enlarge)

June-Chart

SPIRIT II

Thanks to a generous donation from the Hawaiian Property Group in Perth, the SPIRIT program has expanded with a second telescope – SPIRIT II.

The new instrument is a Planewave CDK 17″ telescope, coupled with a more sensitive CCD camera offering twice the field of view of SPIRIT I (see the ‘first light’ image of the near full moon below).

moon_120206-300x300

See more pictures of the SPIRIT telescopes in the image galleries.

Viewing FITS files with FITS Liberator

The ESA/ESO/NASA FITS Liberator 3 released late last year is now a stand alone application and does not require Photoshop.

FITS Liberator is free software that allows you to open astronomical FITS images, examine the header, make adjustments and even save the images as high quality TIFF files for manipulation in your favourite image editing software.

Earlier versions were provided as a ‘plugin’ for Photoshop. This latest release does not require Photoshop and can be used on its own to view and edit FITS files.

More information can be found at the ESA web site where the software can be downloaded at no charge.

Please note that together with RAW and calibrated FITS files, all images acquired by SPIRIT are still provided as high quality JPEG versions that do not require FITS Liberator, or any other specialised astronomical software in order to view and manipulate them. However, including FITS Liberator in your workflow will allow you to quickly access header information from the FITs versions, such as date, time, coordinate and exposure information, which is otherwise not possible using JPEG versions alone.

A guide on how to use FITS Liberator can be found here.