Jul 182014

Here is the Eagle Nebula and open cluster of newly formed stars NGC6611 presented in false-color.  Two hours of data was taken through a 6″ f/4.8 mak-newt and two more through a 14″ SCT at f/7 through an Astronomik 12nm H-alpha filter with the Canon 500d.  The data from the C14 was blended into the core of the data taken with the ES152, as the 10 minutes subs with the faster scope slightly overexposed the core (where the pillars of creation and spires are).


Jul 092014

I’m progressing on tuning-up the new scope.  Unfortunately, just when I got things right the clouds came and will be here for a few days (although with the full moon this weekend, it’s not a particularly inconvenient time for clouds).  Below is an HaRGB version of the Crescent Nebula taken with the new 152mm f/4.8 mak newt.  I’m not pleased with the little halos around the stars (particularly in the lower right of the frame) which is partially due to a collimation issue and partially due to an aspect of the compression ring mechanism in the ES152′s focuser.  Although the stock focuser on the ES152 can hold the weight of a DSLR rather easily, it has an excessively long draw-tube that vignettes the edge of the frame causing a bit of a diffraction-like chromatic halo around brighter stars.  Also, the screws in the compressing ring that hold the camera’s nose-piece in the focuser appear to be slightly misaligned and when they’re all tightened equally they will tilt the camera’s sensor relative to the optical path.

What I did was to re-collimate accurately using a Hotech 2″ SCA laser collimator (which takes the focuser’s compression ring out of the equation), move the secondary mirror as close to the corrector plate as possible, and reinsert the camera using only two of the screws in the compression ring (I’ll be replacing the focuser after I get an adapter plate made for my Feathertouch focuser).  I was very careful to ensure that the camera remained square to the drawtube after the screws were snug (remember — never tighten anything on a telescope more than it needs to be tightened).  I also added a Teleskop-Service EOS off-axis guider.  Test frames taken afterward showed excellent tracking and collimation across the frame in 10-15 minute test exposures (and on a very windy night with clouds moving in!).

This version was taken prior to all the adjustments, so I plan to go back and add to the H-alpha data.  In the meantime, I’m not displeased with the result.  It’s interesting to compare the image below with this version of the Crescent taken with my 14″ SCT at a focal length of about 2500mm (vs. about 730mm for the mak-newt).


Explore Scientific 152mm f/4.8 Maksutov-Newtonian
Canon 500d (Astrodon modded)
Luminance: 18 x 600s @ ISO1800 (Astronomik 12nm H-alpha EOS Clip)
Color: 50 x 240x @ISO1800 (Astronomik CLS EOS Clip)
Guided through an AT72 with an Orion SSAG on a Celestron CGE Pro mount



Jun 302014

The Veil nebula is a supernova remnant in the constellation Cygnus.  Show below is the western portion of the Veil in visible (RGB) light taken with a modified Canon 500d with an Astronomik CLS filter.  Total exposure was 4 hours and 12 minutes in 4 minutes subs at ISO1600 through a 6″ f/4.8 maksutov newtonian in June, 2014.

Here is a full-frame image.  Click here for a larger resolution.


And a close-up of the wispy filaments of this section of the Veil.


Jun 282014

Here’s a shot of the Wild Duck Cluster (M11) in the Constellation Scutum.  It sits against the beautiful backdrop of the Scutum Star Cloud — a nearby arm of our Milky Way and the many stars in it.  Taken on 27 June 2014 with the 6″ f/4.8 maksutov newtonian through the modified Canon 500d.  70 minutes of total exposure in 2 minutes subs at ISO1600.


Jun 242014

Here is a first-light image taken with a 6″ f/4.8 Maksutov Newtonian.  When properly collimated (which this scope isn’t…yet), it should produce a large, flat field across the APS-C size sensor.  Here’s 3 hours worth of 4-minute exposures of the Gamma Cygnia (Sadr) Nebula in the constellation Cygnus, using a Canon 500d modified with an Astrodon IR/UV filter and Astronomik CLS EOS Clip-in filter (at ISO1600).  The rainbow, diffaction halo is not real.  It’s an artifact resulting from the misalignment of the optical system.  It still looks pretty cool, though.