WT5L Blog

The image shown above is of the globular cluster Messier 53 (M53) located in the constellation Coma Berenices.  All subframes used for this image were captured at the Chiefland Astronomy Village on 23 and 24 April 2009.  All subframes were taken with an unmodified Canon XSi (450D) at ISO 800 for 300 seconds (5 minutes) each.  In all, 21 subframes were used for this image for a total integration time of 105 minutes.  All subframes were calibrated using dark, flat, and bias frames in Maxim DL.  Final image processing was done using Adobe Photoshop with Gradient Exterminator and Noise Ninja plug-ins.  The scope used for this shot was a Takahashi TSA-102s reduced to f/5.96 (608mm) riding on a Takahashi EM-200 Temma 2 mount.  All subframes were autoguided using a Fishcamp Starfish uncooled guide camera attached to a Orion 80mm f/5 short tube guide scope.

In this field of view where north is up and east is to the left, the camera has been centered slighty southeast of M53 in order to capture M53 and the nearby, diffuse globular cluster NGC 5053.  Also in the field to the southwest of M53 is the 4.3 magnitude star Alpha Comae Berenices.  I also captured a very faint (magnitude 14.6) spiral galaxy about 38 arcminutes west-northwest of M53 catalogued as PGC 45710.  M53 is approximately 13 arcminutes in width and shines at magnitude 7.7.  Its distance from Earth is around 56,000 light years and it is also catalogued as NGC 5024.  (Click on the image above to view the full-size photo of M53.)

More information regarding this image can be found here:

http://astro.wt5l.com/m53_01.htm

Jerry Lodriguss has generated a very complete, sortable, and searchable database of deepsky objects and made it available on his website.  The database can be accessed by clicking here.

Jerry is the author of two books on CD-ROM that are both great resources for the astroastronomer.  These books are “A Guide to Astrophotography with Digital SLR Cameras” (which I own) and “Photoshop for Astrophotographers” (which I have owned but have sold).

The images below are the first astro-photos that I’ve captured using my new unmodified Canon XSi (450D) digital SLR camera.  All previous astro-photos have been captured using a SBIG ST-7/8 dedicated, cooled CCD camera.  In order to fully utilize the XSi, I added the Takahashi focal reducer / field flattener to the image train so that the field is reasonaby flat over the entire area of the XSi’s detector.  I also purchased the camera control and image processing software Maxim DL so that I could control the Canon in the same manner that I have been previously controlling my SBIG camera.  This includes the ability to automatically focus using FocusMax softare and automate all aspects of image capture using CCD Commander.

The first image was captured on 13 February 2009 and is a photo of the open cluster M67 in Cancer.  This image is made up of 16 – 2 minute exposures and was calibrated with 5 – 2 minute dark frames.  (Click on the image to view a larger representation.)

[UPDATE 10 April 2009]:  Have now added a web page for M67 at the following link:  http://astro.wt5l.com/m67_01.htm

The second image was captured on 26 March 2009 and is a photo of the globular cluster M5 in Serpens.  This image is made up of 15 – 5 minute exposures and was calibrated with 5 – 5 minute dark frames.  (Click on the image to view a larger representation.)

[UPDATE 10 April 2009]:  Have now added a web page for M5 at the following link:  http://astro.wt5l.com/m5_01.htm

The DXCC status webpage on my personal website is now complete and up-to-date.  It contains three tables:  one table showing my current DXCC account status from the DXCC database, one table showing an accurate accounting of DXCC status using both LoTW and QSL card confirmations (both awarded and pending), and a detailed table of each DXCC entity that I have confirmed and all modes and bands that have been confirmed for that entity.  These tables can now be easily updated to reflect any new confirmations as they are received.  The link to the DXCC webpage is below:

http://radio.wt5l.com/dxcc.htm

For automated focusing, I have a RoboFocus stepper motor mounted to my Takahashi TSA-102S refractor’s focus wheel shaft using the supplied mounting brackets as shown in the image below:

After working out the mounting arrangement, I started working on getting the focuser to work properly with the Tak’s rack and pinion focuser. After a few false starts, I’ve ended up with the following setup:

• Duty Cycle = 0%
• Microstep Pause = 9
• Step Size = 2

At this step size, I have came up with a range of about 6230 steps for the full range of motion of the focuser’s travel (about 3.5?). Taking some measurements with a micrometer, I have came up with the step size for this setup:

• 1000 steps = 0.530? or 1000 steps = 13.46mm
• 1 step = 0.00053? or 1 step = 0.01346mm

The Critical Focus Zone (CFZ) in mm of my Tak TSA-102S (f/8) is 2.2*f*f/1000 or 0.1408mm. Dividing this number by the step size shown above gives the width of the CFZ in steps:

• 0.1408mm/0.01346mm per step = 10.46 steps

Using the focal reducer/flattener, the Critical Focus Zone (CFZ) in mm of my Tak TSA-102S (f/6) is 2.2*f*f/1000 or 0.0792mm. Dividing this number by the step size shown above gives the width of the CFZ in steps:

• 0.0792mm/0.01346mm per step = 5.88 steps