Hull Cabin back in April

Back in April I met Charles and Mike at Hull Cabin, located in the Grand Canyon National Park.  It's one of those park-owned cabins that they rent out to the general public.  It was a nice little cabin with a single bedroom with bunkbeds, a kitchen, and a living room with a fireplace.    The bathroom was located in a separate building which made you think twice about going to the bathroom at night as the temps were in the 30's.  But who am I kidding?  I was awake at night snapping shots of the stars or looking through my scope.

Sometimes you get to a point where you think you'll make a leap forward only to discover that you're still plagued by beginner's mistakes. I had a chance to shoot the Rho Ophiuchus/Antares region in the southern sky.  I had been planning to take the shot for about 5 months as I purchased a decent 135mm lens which frames the area pretty well.

In May of 2013, I tried shooting the area with my 70-200 through my old Canon XT/350D that had been modded by Hap Griffin.  This simple shot was 111 seconds (manually counted by me) on the Celestron CG5 mount.   The F/stop was 2.8 and I set ISO at 1600.

I think I processed the image in Lightroom, but I'm not sure.  Obviously, the focus is off and there is some minor star trailing.   I could never get that CG-5 working well for astrophotography.   No matter how long I spent polar aligning the mount, I always seem to get trailing in exposures greater than 30-40 seconds.

Fast forward to April 2014, I was able to get better results with the Zeiss 135mm lens.  I used the Canon that I had modified a couple months before, shot it at F/3.2 with 1600 ISO.

This shot is a result of 18 x 5 min exposures.  Only bias frames were used during the stacking of the images.  No darks or flats.  But the Zeiss lens is pretty darn impressive without much vignetting noticeable at F/3.2.   Stacked in Deep Sky Stacker.   Brought into Lightroom and Photoshop to bring out better (perhaps too much) color.  And what mount did I use?   The trusty AP900.

What I'm disappointed at is how I can't seem to deal with overly exposed elements in the image.   Both Antares (the bright orange star) and M4 are just too blown out.  And what's up with that halo around Antares?   If you look really close, the fainter stars are not pinpoints, they are elongated.  I guess I could've shot this again at Van Vleck, but I felt I should move on to more targets.   Most of my shots at Van Vleck had perfectly round stars so I'm guessing my polar alignment was to blame.

We also conducted an interesting, short comparison at Hull.   We shot the North American Nebula (NGC 7000) with both my modded Canon T3i and Charles 60Da.   The exposures were identical with identical processing.   Both shots used my Sky-Watcher 66ED with a Williams Optics reducer/flattener. On the left is the 60Da and on the right is the modded T3i.

Both exposures were for 5 minutes at ISO 6400.   Though the shots were autoguided, there was minor trailing.  I was using the CGEM mount.   It's pretty obvious that the modded T3i is letting in more H-alpha light, but the 60Da doesn't do a bad job either.   In a way, I can see why one might be happier with the 60Da.   

At Van Vleck, I discovered that the little Sky-Watcher 66ED had a loose mounting plate.   It made me wonder how long it had been loose as I had been using the 66ED as my autoguiding scope. Luckily, I noticed the loose mounting plate during the first night at Van Vleck.  As a result, I switched to the Orion Miniguider for the week at Van Vleck, which may explain why I never had guiding issues for the week.  

Van Vleck 4 - California, Coccoon, and IC 5068

Feeling the end of the week coming up fast, I decided to shoot three objects (Lagoon, Coccoon, California) on our fifth night and one object (IC 5068) on our last night.

Shot in the early morning hours of 8/27, the Coccoon Nebula (IC 5146) is a curious object.  It's hard to observe visually in any instrument smaller than 14-16 inches.  What you usually see is the associated dark nebulosity trailing behind it.   These inky dark trails are usually identified as LDN 1035 or Barnard 168.   The "LDN" being a designation from Lynds' Dark Nebulae catalog.   I couldn't find much on "Lynds" except that the catalog founder is a lady named Beverly T. Lynds.

This is a center crop of 22 x 5 min shots at 1600 ASA with the Canon T3i shot through the Explore Scientific 80mm F/6 scope.   I also used the Televue .8x reducer/flattener.   Darks, Flats, and Bias frames were used to produce the image.

Since we were in California, I figured it wouldn't be a real trip unless we photographed the California Nebula (NGC 1499).  NGC 1499 is a large emission nebula in the southeastern part of Perseus.  Like the Heart Nebula, it's an object that's suitable for a small scope or a telephoto lens.   Out of laziness and necessity I chose not to turn the camera to frame the target as that would require shooting a whole new set of flat frames.   By happy accident, it's oriented in a way that shows its resemblance to the state.

Full frame of the T3i with 24 x 5 min shots.   With the usual darks, flats, and bias frames stacked in Deep Sky Stacker 3.3.4, color balanced in Lightroom, then tweaked in Photoshop.

Originally, I was planning to take the last night off so I could do some preliminary processing and catch up on sleep before the 13 hour drive back home.   But the whole afternoon I kept noticing how much the sky was deep blue -- usually a sign of great transparency.   So I decided I would photograph for a few hours - until maybe midnight.   I wasn't sure what to shoot.  My original plan was to shoot the Veil, but as I was studying the Cygnus region in my copy of Sky Atlas 2000, I noticed an interesting nebulosity (IC 5068) BELOW the North American Nebula.   This little area shows three concentrations of nebulosity.   

IC 5068 seems to be part of the same complex of nebulosity associated with its more prominent neighbor NGC 7000.   In the lower right corner, you can see the southern most tip of the North American nebula.

What's interesting to me is the "blocky" or square structure in the target area.   There almost seems to be dark nebulosity "combing" across the area as if there were dark clouds obscuring the object.  

This target got 30 x 6 min exposures at ISO 1600 on the Canon T3i.   The temps were running really hot in the 22-23 deg Celsius range which even after applying Darks, the target appears unusually noisy.

But all in all I'm happy with the image as it's something slightly off the beaten-track of astrophotography targets.  A good last target for a week of learning and confidence building in astrophotography.

Van Vleck 3 - Lagoon and Heart

So part of my "mission" at Van Vleck was to capture at least one of the summer targets in the Milky Way.
After some consideration, I decided upon the dual targets of the Lagoon (M8) and the Trifid Nebula (M20, M21).   Both of these targets are in Sagittarius.

The image is a result of 22 x 5 min exposures with darks, flats, bias.   I used the trusty modified Canon T3i at 1600 ASA (for the whole trip).  Explore Scientific 80mm F/6 with Televue .8x reducer/flattener (TRF-2008).  For reasons that I couldn't figure out, the camera was running hot at 18-24 degrees Celsius.   Lots of extra H-alpha nebulosity hinted at the region.   I know there's a lot more data there, but I'm fine with what I got.

I also shot the Heart Nebula (IC 1805) which I've shot a few times before.  It's a fairly large target that is suitable for smaller scopes and telephoto lenses.   This target (as well as its companion, the Soul Nebula) lie in the western part of Cassiopeia.

This is a result of 30 x 6 min shots.  So, one of the longer exposed images of the trip.  Darks, flats, and bias frames taken.   I was suprised at how much noise there was in the image overall.  Looking at my files it seems these shots ran pretty hot at 17-18 deg Celsius.  Having shot this camera a lot at home, I know there is an obvious improvement in image noise when you can get it down to 3-4 deg Celsius.  Hm...

At the end of the night, I was curious about the Sculptor Galaxy (NGC 253) which is fairly large by galaxy standards.   This is a simple 10 min shot of NGC 253 and its Globular friend NGC 288.

Couple of things to immediately note of this single frame:  Vignetting!   And noise.   

I would love to get down to Southern AZ and photograph this pair again with maybe 30-40 subexposures.

Van Vleck 3 - Polar Alignment Notes

LINK TO METHOD I USE:  http://www.cloudynights.com/page/articles/cat/articles/darv-drift-alignment-by-robert-vice-r2760

On the fourth day I finally felt confident that I had really solid polar alignment - mostly because I had been doing it for 3 nights straight.  I use a method that relies upon shots taken in the south and the east.

I start out by roughly polar aligning the mount to Polaris.   Having a polar alignment scope can help immensely in this initial alignment step.  Then, to begin the procedure, I point the telescope with the camera to the south, about 10-15 deg above the horizon.  Then I do a short test exposure of about 50 seconds.   For the first ten seconds, I just let the exposure run as is.   Then for 20 seconds, I press the left button on the mount keypad.  I should preface this by saying that I've set the mount control speed to either the lowest or next to the lowest setting on the hand controller.   Then after the 20 seconds have passed, I press the right button.

The following image is a result of the above procedure:

What you end up with is a bunch of lines that have a "head" or dot at one end.   That dot was created by the initial 10 second exposure and the lines represent the movement caused by your hand controller.

A closeup of the left upper corner reveals an interesting picture:

In the middle of the closeup you can see a golden line created by a star.  As mentioned above, the dot is a result of the 10 second hold at the beginning of the image.  Then you see the line going down that was a result of pressing the left button on the mount keypad.  As you notice there are two lines which is the result of pressing the right button.   The line connected to the dot is the line made by the left button and the incomplete line is made by the right button.   What's important here is the GAP between the two lines.  What you're trying to accomplish is a "collapse" of that double line into a single line.

How do you that?  If the scope is pointing to the south, then you move your azimuth (left-right adjustment) on your mount just a little bit.   Then you repeat the above procedure to see if that gap between the two lines has increased or decreased.   After a few iterations, you should be able to collapse that gap so that it's just one solid line coming from the dot.

Once you've accomplished this you move the scope to the east about the same angle above the horizon and repeat the procedure.  EXCEPT now you are making physical adjustments to the altitude (up-down adjustment) of the mount.   The same phenomenon will occur.   As your lines collapse, you approach the appropriate altitude for good polar alignment.

To further refine the polar alignment you can increase the time interval for creating those lines above.   After I collapse the lines at 50 seconds, I will typically go back and do the same procedure at 170 seconds.  When you are satisfied with 170 seconds in both azimuth and altitude, then you should have good enough polar alignment for an unguided 2 min shot.    And it's certainly good enough for autoguiding.

Van Vleck 2

The cabin is a forest service owned building which they rent out for part of the year.   It's pretty basic with a main living area, kitchen, 1 bedroom, and 1 bathroom.   The place runs on propane gas and a spring supplies water.  No electricity.  Our stay was largely uneventful except for a rodent (mice) problem.

One of the challenges of doing remote astrophotography is power.  Laptops, telescope mounts, and dew heaters all need electricity.  Fortunately, the dew was a minimal problem and I only had it show
up one night later into the evening/morning.  In the photo above, you can see our impromptu "recharge station" powered by a 2000 watt generator.   The Hyundai generator ran like a champ all week.   It consumed about 6-7 gallons of gas in total and ran about 35 hours.

Here's our two setups (partially disassembled) during the daytime.

On our 3rd night out, I got a chance to photograph the Helix Nebula (NGC 7293) located in Aquarius which is in the eastern-southeastern part of the sky.   This part of the sky doesn't contain many obvious targets for a smaller telescope, but it has many galaxies.  The Helix is about 700 light years away (Wiki) and is a planetary nebula.   Its size is a result of its closeness.  Most planetary nebulae are further away than the Helix.

This shot is a stack of 31 x 5 min shots.   (1600 ASA -- all shots at VV were at 1600).  Flats, darks, bias.
Processed via DSS, Lightroom, and Photoshop.  This is a crop of the approx. 50% of the area of the original.   Couple of nitpicks:   1)  Target is a little small for a 80mm scope.   2) The hints of red circular nebulosity to the lower left of the nebula really speak to the need for doing this target as a composite (like M31) by doing a series of 15-20 minute exposures as well.

Van Vleck

Sorry for the long hiatus.   I had some images from a trip to Hull Cabin in April, but I was a little disappointed with the results so I didn't post them.

This August marked the second get-together at a cabin in Northern California with Charles.   Last year, it was a kind of discovery trip as I didn't really bring any imaging gear.    The skies at Van Vleck Bunkhouse are pretty good and since summer is monsoon season in Flagstaff, it afforded an opportunity to photograph and enjoy the summer constellations and "goodies" in the Milky Way.  We had 6 nights at the cabin and the weather held steady for a solid 5 nights.  For me the first night was getting back into the routine of polar aligning and it took me a pitiful 4-5 hours to get things right.   It wasn't until well into the second night that I finally felt I had all my ducks lined up.

But even on the second night, I didn't take many long exposures.  I finally got a series going on good 'ole M31, the Andromeda Galaxy:

This photo of M31 is a composite effort based upon 15 x 5 min shots and 15 x 1 min shots.   I used the Explore Scientific 80mm F/6 APO with a Televue .8x reducer/flattener.  I took darks, flats, bias shots and used Lightroom as well as Photoshop to process.   Images were stacked using Deep Sky Stacker 3.3.4.  For the whole week the scope was mounted in a dual-saddle configuration on an AP900 mount.   Guiding was done with an Orion 50mm Guidescope with a QHY5L-II autoguider.

Although I'm satisfied with the shot, during processing, I could see there's definitely faint detail to be culled around the edges of the galaxy.   I believe a series of long exposures (15 x 15 min ???) would give me the data I would need to really capture the halo outside the perimeter of the present image.

Toward the end of the night, I thought I'd point the scope at the Pleiades (M45) and see what I could get with 15 minutes of exposure.  Taken at 3:52 in the morning.  Sensor temp: 14 deg. Celsius.