Moon

Just a quick post to let everyone know that I'm still here. It's been a few months since I've done anything with my own scopes. Tonight, the kids and I went outside to look at the Moon, and I took a few shots. Nothing spectacular. But I am very pleased with this Baader Contrast Booster filter. It does a really good job mitigating the chromatic aberration produced by the ST80.

The Moon, December 17, 2015; ST80 w/CB on Vixen SP
42 images, ISO-100, 1/200 second exposures

X Bar Ranch Nature Retreat

My older son and I spent a couple of nights at the X Bar Ranch Nature Retreat near Eldorado, Texas. The ranch features hiking and bike trails, and they have observing fields for amateur astronomers. They also host the annual Eldorado Star Party.

The sky at the X Bar Ranch is rated Class 2 on the Bortle Scale, which is almost as dark as possible. The night sky is amazing!

Below is a panorama of the one of the observing fields, taken from the deck of the Live Oak Lodge. The area is kept mowed, and electrical outlets are located on the back of the lodge and surrounding cabins:

We stayed two nights, but it was only clear on the first night. Seeing was steady above about 20 degrees, with some haze below that. I set up in a small field outside of our cabin and took some pictures of the Milky Way, and the Lagoon and Trifid nebulae. Here is a single 2-minute exposure of the Milky Way taken at ISO-3200 with the Canon EOS Rebel T3 (1100D) mounted on the Vixen Super Polaris:

The very dim illumination of the field at the bottom of the image is from some small, solar-charged walkway lights located behind the camera. The regular observing field is darker.

This is a crop of a stack of 27 2-minute exposures at ISO-3200:

Compare that image to images that I took at the same time two years ago from the SHSU Observatory. While I am pleased with how the older images turned out, they required a great deal more processing to tease the stars out from the light pollution. Most of the time that I spend processing images is usually concerned with removing haze and gradients caused by city lights. More on light pollution later...

One of my goals that night was to make a mosaic of four to six images in the area around the Lagoon and Trifid nebulae. Time was running short, though, and the Trifid was in the haze by the time I got to it. I had to settle for three sets of images. Still, I think it turned out well over all. Here is a mosaic stitched together using Microsoft Image Composite Editor (free software alert!):

Each of the three images is a stack of 12 2-minute exposures at ISO-3200. All were taken with the Canon EOS Rebel T3 (1100D) on the Orion ShortTube 80 with a Baader Contrast Booster filter. The scope was mounted on the Vixen Super Polaris.

I'm really impressed with how well the Baader Contrast Booster works at minimizing chromatic aberration. After using this filter a few times I've concluded that my ShortTube 80 crown/flint achromat is now working about as close to the performance of an ED achromat as it ever will. If only I could find a 1.25" field flattener...

Here are close-ups of the Lagoon and Trifid from the images that compose the mosaic:

Messier 8, The Lagoon Nebula

Messier 20, The Trifid Nebula

The sky here at the ObservaRory is about a 4.5 on the Bortle Scale. The Milky Way is fairly bright overhead, but is lost in the light dome of Huntsville, Texas near the horizon. The difference between the ranch's Class 2 sky and my Class 4.5 sky was immediately apparent, both to the naked eye and through the scopes. Even the polar alignment scope on the mount had a better view at the X Bar Ranch!

To illustrate the difference, compare these two subs taken exactly one month apart. Each image is a 2-minute exposure taken at ISO-3200 with the same equipment under similar weather conditions. No processing has been performed on either image, except to reduce them for display here. (The yellow cast was caused by the Baader Contrast Booster.)

Bortle Class 4.5 Sky at the ObservaRory

Bortle Class 2 Sky at the X Bar Ranch

Besides the darker background, many more stars are visible along with fainter portions of the nebula.

I am definitely spoiled by the sky in West Texas. I plan to make more trips as often as I can.

I hope to visit the X Bar Ranch again, too. The accommodations are comfortable, and the scenery is beautiful. The Meador Family, who own the ranch, are terrific hosts. They've thought of nearly everything and seem very friendly. If you happen to head that way, also check out the Caverns of Sonora:

Lower Room, Caverns of Sonora

Pluto

On the evening of July 14, 2015 I took a picture of Pluto to celebrate the flyby of Pluto by NASA's New Horizons spacecraft. But, there was a problem: I couldn't find it!

Pluto is very small, and also very dim. It is typically around 14th magnitude, which is about 128 times dimmer than the human eye can see in Earth's darkest skies. It's not even visible in most amateur scopes, outside of using long-exposure photography. In addition, the part of the sky that Pluto is currently located in is along part of the Milky Way. How was I to locate such a small, dim object among all of those stars?

Plan A was to use my various planetarium programs to find reference stars that would aid in locating Pluto. That failed because none of them had enough stars in their databases to account for everything I was seeing. I made an educated guess (which I discovered was correct), but there was no way to tell for sure until I could implement Plan B.

Plan B was to use a technique similar to that used by Pluto's discoverer, Clyde W. Tombaugh. Tombaugh worked for the Lowell Observatory in the 1920s and 1930s. He would select a part of the sky and take a picture of it with the observatory's 13-inch astrograph (a telescope designed for photography). A few nights later he'd take another picture of the same area. He then used a blink comparator to look for differences between the photographs. Objects that stayed in the same position were stars, but anything that moved was a comet, asteroid, or a planet.

I took my second set of images on the night of July 24, 2015. After processing and lining up the images I was able to see that my suspect Pluto was, in fact, the real thing! The animated GIF below shows Pluto's position on the two nights:

Pluto! Click on the image for a larger view.

To further illustrate how inconspicuous Pluto is, I put together this movie from the July 14th image:

So, there you have it. A mundane little dot moving among a sea of other dots. Who knew what a beautiful little world Pluto would turn out to be?

Public domain image courtesy of NASA and Wikimedia Commons.

Waxing Moon, July 24, 2015

The Moon, July 24, 2015; ST80 w/CB on Vixen SP
38 images, ISO-100, 1/160 second exposures

Click here for the full-size image.

This is my first attempt at imaging the Moon using the new Baader Contrast Booster filter. When I image the Moon with the ST80, I generally use the stop-down adapter that's built into the dust cap. This reduces chromatic aberration, yielding a sharper image with a less-pronounced red/blue halo surrounding the Moon. The disadvantage to using the adapter is that it greatly reduces the telescope's aperture, which reduces the amount of detail in the image.

This image was made without using the stop-down adapter. It was stacked in RegiStax 5.1 and processed in Photoshop CS6. There were some color anomalies, but I hid them by slightly desaturating the image and adjusting the curves a bit. The ST80 certainly doesn't capture the Moon's color characteristics as well as the Epsilon 200, but overall I'm pleased with what the filter can do.

Next, I may try using a Barlow to get a closer view.

Baader Contrast Booster

This post is fairly long, so here are the pictures. I'll meet you on the other side!

Messier 8, the Lagoon Nebula; ST80 w/Baader CB on Vixen SP; Canon EOS Rebel T3; 11x120 @ ISO-3200

Messier 7, Ptolemy's Cluster; ST80 w/Baader CB on Vixen SP; Canon EOS Rebel T3; 32x60 @ ISO-3200

Back in February I purchased two new toys for my ST80/Vixen Super Polaris rig: a Baader Contrast Booster with IR-Cut filter, and an ADM dovetail saddle adapter. Family, clouds, weather, clouds, personal health, clouds, work, clouds and clouds prevented me from doing any astrophotography until mid-July.

The Vixen Super Polaris was the last mount of the Polaris line that was produced without a dovetail saddle. Personal budget limitations have prevented me from upgrading to a modern mount, but ADM Accessories makes an adapter within my price range. The VSAD-SP bolts to the top of the mount head. Two large, spring-loaded screws on the saddle grip the male dovetail bar very securely. Installing and removing the scope is very easy now. In addition, the telescope and camera can be properly balanced on the declination axis, which was impossible before because of the size of the scope and arrangement of the rings.

I'm always trying to find ways to get better images out of sub-par equipment. The ShortTube 80 is a great little scope for casual viewing, but the chromatic aberration inherent to fast achromats makes it unsuitable for imaging. A quality imaging scope is still outside of my price range for the foreseeable future, so I am trying to make the best with what I've got.

My research and experimentation led me to try the Baader Contrast Booster. The Contrast Booster filters out wavelengths on the extreme ends of the visible spectrum that are responsible for much of the blurring and halos caused by chromatic aberration. It also filters out wavelengths produced by common sources of light pollution.

I had the opportunity to try the filter visually against the Great Orion Nebula back in March. The moon was at 68% illumination and the nebula was about 30 degrees above the light-polluted horizon. Despite all of that, I could see a remarkable difference in contrast.

The two images above were made using the Baader Contrast Booster. The chromatic aberration, while not competely removed, was significantly reduced. This was a major improvement over my best results with the Orion SkyGlow Astrophotography Filter and the #15 yellow filter discussed in the Fixing Halos post.

The three following images illustrate the differences among the filters:

Baader Contrast Booster

Orion SkyGlow Astrophotography Filter

Yellow #15

The stars in the Contrast Booster image are larger, but that may be due to the fact that it was shot at ISO-3200 versus ISO-800 for the other two. The important thing to note is that the halos are confined to a tight ring around the stars.

The image of the Lagoon Nebula at the top of the post was processed without attempting to remove the effects of chromatic aberration. I applied the Color Layer technique to the image of Messier 7 to reduce an overall purple hue that was likely the result of all of those bright stars.

I was concerned that the Contrast Booster might cut out too much blue from the images. Pure blue hues are not common in astroimages. The best example that I can think of is Messier 20, the Trifid Nebula. This nebula presents a striking contrast between a red emission region and blue reflection region. The image of M20 below was compiled from only five subs, so it is fairly grainy. However, the blue came through the filter nicely:

Messier 20, the Trifid Nebula; ST80 w/Baader CB on Vixen SP; Canon EOS Rebel T3; 5x120 @ ISO-3200

I plan on doing more tests and reimaging more objects with the Baader Contrast Booster. So far, however, I think this filter brings the ST80 close to the performance of an ED refractor--at least as close as it can reasonably get.

Messier 51 and Omega Centauri

The sky has been clear for the past few nights, and last night I finally got some observatory time! Most of the night was spent helping another amateur astronomer with his scope and making adjustments to the Epsilon-200, but I did get a little bit of time for imaging. The first, an image of the Whirlpool Galaxy, was created from a series of test shots. The focus is a little off, and some of the fainter detail didn't show up because of a bright moon (68% illumination). Despite the problems this image is actually better than my previous attempts. I did not shoot dark, flat, or bias frames.

Messier 51, the Whirlpool Galaxy; Epsilon-200 on NJP; Canon EOS Rebel T3; 8x180 @ ISO-1600

Globular cluster Omega Centauri is a monstrous cluster that appears very low on the horizon (about 11 degrees at most) from my latitude. I've seen it visually once, and have wanted to image it for years.

The problem is that it is only visible for a few minutes from where the Epsilon-200 is located at the SHSU observatory. I imaged it as it passed between a couple of trees at the the south end of the observatory. Seeing is bad that low down, and it is within the light domes of several cities.

Omega Centauri; Epsilon-200 on NJP; Canon EOS Rebel T3; 33x30 @ ISO-1600

The Five Stages of Astronomical Grief

The weather pattern these past few months has not been conducive to viewing or astrophotography. As I mentioned in a previous post, when the sky hasn't been cloudy the humidity has been high. Throw in a busy schedule and an intense need for sleep, and I haven't gone out much lately.

And it appears that I am not alone. A LOT of folks have been complaining about the clouds.

A recent post on a forum on which I participate got me to thinking that there may be a relationship between grief and the feeling we amateur astronomers get when we can't go out and play for long periods of time. So, I mapped out the stages of grieving in relation to the Cloudy Night Blues. After all, I need SOMETHING to do that's at least moderately astronomy-related.

Stage 1: Denial

Maybe the weather will improve. Astronomers have to hold onto whatever tenuous shreds of hope they can grasp. Hey, sometimes the weather forecasters get it wrong! But all too often they are correct or, worse, they predict clear skies and it clouds up again. All of this eventually leads to...

Stage 2: Anger

Why won't these !#@$=! clouds go away? Our inability to control the weather, coupled with an intense urge to do astronomy stuff often results in increasing frustration. Frustration can sometimes blind our reasoning. OF COURSE there are valid reasons for clouds, and our opinion of and dislike of them are of no consequence to Mother Nature. The cycle of frustration, impotent rage, and meteorological ambivalence to our condition brings us to the point of...

Stage 3: Bargaining

Maybe I can view between the clouds, or, God, if you make the clouds go away then I'll [insert promise you will never be able to keep here]. In this stage, we may attempt to adapt to our circumstances, or we may become delusional...or both. Either way, those who reach Stage 3 are well on their way to potential emotional disaster if the weather does not improve. There is no magical cure for cloudy weather, and often the cycle of clear-to-clouds-to-clear takes several days or weeks, depending on the season and local climate. When we realize that our best efforts to cope with or appeal to nature's good graces are useless, we experience...

Stage 4: Depression

I'll never see the stars again. What is the point of all this? Prolonged suffering generally gives way to despair. Many torture victims describe a point at which their torment overwhelms their convictions and they give in. Only with clouds, giving in doesn't make them go away, so then there must be...

Stage 5: Acceptance

I need a new hobby, or, I will be patient, then when the time is right I'm taking a personal day from work and spending all night outside. Nothing lasts forever. Not even clouds. Well, maybe they do in some places. At any rate, just accept the clouds for what they are. Or don't. Either way, there's nothing you can do about it.

Moon/Venus/Mars Conjunction

Clouds. Clouds, clouds, clouds, clouds, clouds, clouds. It's been cloudy lately. A lot. And when it isn't cloudy the humidity is so high you can practically drink the air.

I thought I was going to miss the Moon/Venus/Mars conjunction on February 20, 2015, but the clouds parted just long enough for me to take a few shots. This one is my favorite.

Moon, Venus, and Mars. Venus it the brighter star to the left of the Moon. Mars is the star above and to the right of Venus.

Did I mention that it has been cloudy?

Asteroid 2004 BL86

I was sick, but I couldn't resist the temptation to image part of the flyby of asteroid 2004 BL86 the other night. Below is a time-lapse video taken of the event as the asteroid moved across Messier 44, the Beehive Cluster. Of course, both objects are VERY far apart. The asteroid was about 4 light seconds away (approximately 3.1 times the distance between Earth and the Moon), while M44 is around 577 light years away.

The video compresses about 27 minutes down to 6 seconds.

Each frame is a 20-second exposure taken at ISO-3200 with a Canon EOS Rebel T3. I did not use autoguiding, so there is some visible periodic error. Passing clouds cause the brightening and dimming of the background.

This is the first set of images taken with the Takahashi Epsilon 200 since I cleaned the mirror. The collimation is still a little off, but I didn't have time and energy that night to fine tune it. I'm looking forward to getting the scope back into full service soon!

Astrograph Maintenance

The SHSU observatory is the proud owner of a rare gem: a Takahashi Epsilon 200 astrograph. It is a fast (f/4) Newtonian telescope with a hyperbolic primary mirror and a dedicated field-flattener lens. It was designed specifically for astroimaging. Dr. Anjal Sharma, with the help of Mike Prokosch, Brian Neitfeld, myself, and others worked to restore the telescope and its mount to operational condition and to establish procedures for producing images. Anjal documented the restoration in Resurrecting an Old Classic. The Epsilon 200 has not been manufactured for about 20 years now, and according to Anjal there are probably only about three dozen of them in existence worldwide. Maintaining and using this exciting piece of equipment has been a pleasure and a privilege, and I hope that it will be of benefit to SHSU and its students in the future.

Anjal had to focus his energies elsewhere, and so left me more-or-less in charge of the scope and its care. However,I haven't been able to make trips to the observatory as frequently as I did before my youngest was born. As a result, the Epsilon 200 has not had much use, and it has not been maintained as well as it should. It's a great scope and is capable of capturing some beautiful images, so I'm slowly trying to bring it back up to a presentable and operational state. I reread Anjal's account of the restoration and a few Takahashi manuals (for similar scopes), and decided to tackle cleaning the mirror.

The mirror was a mess. Dirt, smoke, dust, mold, spiders, various other fauna and a strange green fibrous substance have slowly built up gunk on the mirror over the years. Below is a photo of the mirror in its cell. Note the cobwebs. There were several spots of mold and something else that I can only describe as a "biological byproduct." The mirror is held in place by six clips. In addition, six small compression washers hold the sides of the mirror down inside the cell. It's in there pretty snugly.

Here is the mirror removed from the cell. Working on this telescope has made me appreciate even more the quality of workmanship that Takahashi puts into their products. This is a serious telescope that was meant to be used for serious work.

I placed the mirror into a plastic tub filled with distilled water and dish soap. Distilled water should be used because tap water and bottled drinking water contain minerals that can leave deposits. After letting it soak for an hour, I very carefully cleaned the surface with cotton balls. (The trick with the cotton balls is to move them from the inside out and to not put any pressure other than their own weight on the mirror surface.)

After three passes with the cotton balls, I rinsed the mirror with more distilled water and let it air dry. Below is the result. There are a few specs of dust that landed while it was drying, and a few spots that did not come clean. These are optically insignificant.

I also cleaned dust and cobwebs out of the tube, collimated the scope, and realigned the finders and the guide scope. Here is the reassembled scope.

I wish I had remembered to bring a DSLR, but here is a photo of some birds sitting on a power line about a quarter of a mile away, taken afocally with my phone through one of the few eye pieces that will come to focus on this scope.

I'm not an expert on telescope mirrors, but this mirror looked practically brand new after its cleaning. I'm convinced that it will continue to serve up beautiful images for many more years.

There is still more work to do:  fine-tuning the collimation, cleaning up the mount, and cleaning out the shed. In addition, I am going to write up an operations manual for students and faculty who want to use the scope for research.


A follow-up report on the astrograph:

After reassembling everything, the scope sat for quite a while before I had the chance to go out and collimate it. I struggled and fought with the adjustment screws, but could never get it quite right. This was not unusual, though, as we've never gotten the mirrors aligned properly.

We took it to Land, Sea, & Sky, Takahashi's authorized distributor in the Americas, for alignment and further cleaning. Fred Garcia, the Tak expert, reported that the primary mirror was not installed correctly! Well, color me Takahashi yellow!  I'm guessing that the mirror was misaligned even before Anjal rebuilt the scope, because he marked the mirror position before cleaning it years ago. That would explain why we've NEVER been able to get it properly aligned.

As of this update (June 2016) I haven't had time to do any imaging on the Epsilon-200 since it was fixed. However, the university has been putting it to good use observing exoplanet transits!

Don't Panic!

Maybe Douglas Adams was on to something when he wrote "Don't Panic!" The mount is fixed!

I took the clutch assembly and RA motor dust cover apart and found that the gear on the RA motor had simply come loose. I reattached it and now it is working fine, assuming I got the gear spacing correct.

Wandering Aimlessly Through the Stars

Bad news, at least for me. My Vixen Super Polaris mount has stopped working.

I was taking pictures of C/2014 Q2 Lovejoy the other night when the mount stopped tracking. I assumed that the batteries were dead, but the power light was still its normal brightness. It has always gotten dimmer when the batteries finally run out of juice.

I put in a fresh set of batteries and went out tonight to try imaging the comet, only to find that the clutch is apparently not engaging with the RA motor.

So, I guess I'll be out of the astrophotography gig for a while, except on the rare occasions that I can make it out to the observatory. I've been thinking about buying a new mount, anyway, but that may be much later than sooner. In the meantime I am going to take a stab at fixing this one. Wish me luck(y stars)!

Comet C/2014 Q2 (Lovejoy) - Up Close

I finally got a break in the weather on January 7 where I could go out and image C/2014 Q2 Lovejoy. Even in the 91% illumination of the waning Moon, the comet was still visible to the naked eye in the constellation Eridanus. While not as visually interesting as, say, C/2011 L4 PANSTARRS, I think it is the prettiest comet that I've imaged so far. Other amateur photographers have made some stunning images. Here is mine, made with my modest setup:

Comet C/2014 Q2 Lovejoy; ST80 on Vixen SP; Canon EOS Rebel T3; 43x30 @ ISO-1600