The “Straight and Narrrow Path” – Narrow band imaging part 3

Hubble’s iconic 1995 “Pillars of Creation” image

In part 2 of this blog mini-series on narrowband imaging we saw how the iconic Hubble image of the “pillars of creation” gave birth to the so-called “Hubble palette” mapping the sulphur, hydrogen and oxygen narrow band filters to red, green and blue respectively. The rationale for this approach was set forth by the Space Telescope Science Institute in their Astrophysical Journal article of 2005:

“An example of an image produced using the chromatic ordering scheme is the Hester &
Scowen (1995) HST image of M16. The data (Hester & Scowen 1995) were obtained with
the HST WFPC2 camera with the F502N ([OIII] _5012_A), F656N (Halpha _6564_A) and F673N ([SII] _6732_A) narrowband filters. To generate the image, the three datasets were colorized blue, green and red respectively. Filter F502N was assigned blue because it has the shortest wavelength passband,filter F673N was assigned red because it has the longest wavelength passband, and filter F656N was assigned green because its passband is of intermediate wave-length compared to the other two. The chromatic ordering for the HST M16 image is not a natural color scheme because the filters were not assigned their visible colors. That is, when viewed against a bright, white light, the F502N filter appears to be green, not blue, to the human eye. Similarly, the F656N filter looks a deep red, not green. Only the F673N filter is assigned its perceived color, red. It is also not a natural color scheme because it uses narrow-band filters that pass only a very small fraction of the visible spectrum. Furthermore, rather than photometrically calibrating the projected images they are balanced so that the H-alpha data doesn’t dominate and turn the image completely green. In comparison, a natural color image of M16 (Shoening 1973) shows the nebula as deep red, again because of the strong H_alpha emission from the nebula. The color assignment chosen is an extreme version of the hue contrast. The image is also an example of a split complementary color scheme. The blue (from the [OIII]filter) and the green (from the H_ alpha filter) combine to generate a background of greenish-cyan, whose complement is a slightly-red orange. Areas of the pillars are yellow-orange and orange-red which are on either side of this orange on the color wheel, hence the complement is split.
Also the RGB assignment to each layer, along with the intensity stretches, ensured that
the combined datasets produced cyan, magenta and yellow, resulting in a strong contrast
of hue in the undiluted primaries of the subtractive system. Where the intensity of [OIII]
(blue) and H_ (green) are balanced, cyan appears in the background. The H_ (green) and
[SII] (red) images combine to produce yellow along the edge of the pillars. And, while the
center of the stars are white due to the equal combination of RGB, their halos are magenta because the F673N filter broadens the point-spread function. Itten (1990), in his section on this contrast of hue states, the undiluted primaries and secondaries always have a character of aboriginal cosmic splendor as well as of concrete actuality,” a statement that applies to the HST image of M16. The two supporting contrasts, (split) complementary and light-dark further boost this image’s appeal.”

Today I demonstrate my experience with this in a recent image I took of the Lagoon Nebula- Trifid Nebula complex. This is a popular region amongst astroimagers as it encompasses the dense star fields of the southern portion of the Milky Way band, toward the center of the galaxy.

Three starless images from the top left: H-alpha, SII, OIII open in the Pixinsight processing program and on the right side showing the assignment of the Ha, SII, OIII channels to red, green and blue respectively. This happens after the step shown below.

In Pixinsight you simply double click on the image file name in the list at the right and it will appear under the color tab you intend to match it to. In this example we have the red tab open at the left and we will click on the SII image file in the list shown. Then you click on the green tab at the top left, enter the Ha file and do the same for blue and OIII. Click ok and you go back to the main screen above where you apply the settings to arrive at your color image. And that’s it!

Today’s image processing software allows for an infinite number of options for combining the H-alpha, SII and OIII channels. In the example above I have three starless versions of the nebula in each of the channels. In most programs all you do is enter the image file in the appropriate field depending on how you wish to do the r-g-b combination.

Again, the recommendation put forth by the Hubble Heritage team is to assign sulphur, hydrogen, oxygen to r-g-b respectively. However since it is false color as we discussed in the last post and also pointed out in the article above, there is no law prohibiting experimentation!

Here is a typical broadband image of the Lagoon Nebula. Notice the dominant pink color. This is what we amateurs have pretty much permanently stamped in our minds of how the colors “should” look

 

In this example H-alpha is assigned red, OIII to green and SII to blue. This is a common practice interestingly for the Canada-France-Hawaii team at the Keck observatory on Mauna Kea, Hawaii

In this example above an H-O-S assignment was given and the result is quite pink but the idea here is to try and represent the nebulae in more of a “natural” color scheme as you would see for a typical broadband image

 

HSO palette assigning H-alpha to red, SII to green, OIII to blue. This was my idea to try and get the color closer to what you would see with a broadband image

This was something I tried which was an “HSO” palette. At first I really liked this because the Lagoon nebula is pink and that is what it typically looks like in broadband but after further processing I could not wrap my head around around a white Trifid nebula which is the smaller object to the right.

 

The “official” Hubble palette. S-H-O

So here it is folks! The official “Hubble palette”. This looked absolutely awful when I first saw it. I think the problem most of us have when we first get into this is the dominant green color which is very difficult to wrap your head around! It is important to note that for amateur data, the Hydrogen alpha channel is by far the strongest and when you assign this to green, the green will totally overwhelm everything. However this can be corrected with the processing software so you can dial the green down as much as you like.

After experimenting with the different combinations, I decided first off that the Trifid nebula portion of the image was not going to work at all. My choices were white or yellow. If you do this long enough you are so used to seeing objects a certain way that the false color just cannot work with certain targets. So I cropped that section out. I put aside my prejudices regarding green and followed the Hubble palette “doctrine” to arrive at the final solution shown here:

This is my version of the Lagoon Nebula in narrow band using the Hubble palette principles. The sulfur data was mapped to red, h-alpha to green and oxygen to blue. All of the colors are there. I obviously dialed down the green quite a bit but there is still green in there and the complementary colors are correct according to the article. I think it will take some time to get a “feel” for this approach in terms of what is presentable and what isn’t. I think the take home point is that if you are doing narrowband imaging and wish to present your results, best bet is to follow the directions set forth in the article discussed above and use the Hubble palette of S-H-O, rather than trying to make the image “look” like a broadband image which it can never be!

Thanks for reading!

DrDave

The “Straight and Narrow Path”- Narrow band imaging part 2

Last time we discussed the basics regarding color in the universe and typical “broad band” color imaging, how it differs from narrow band imaging and how the eye is not well adapted for night time color detection but despite that we have come to a consensus regarding “natural color” in the universe. We also saw how the Hubble Space Telescope is almost always utilizing narrow band filtering, either in the visible spectrum but very often outside of the visible realm (e.g infrared, ultraviolet etc). This method improves resolution by focusing on just the physical phenomemon being observed and “filtering out” the background.

Hubble’s iconic 1995 “Pillars of Creation” image

About 25 years ago now the HST (Hubble Space Telescope) pointed its’ “Wide Field Planetary Camera 2” WFPC2 at a central region in the Eagle Nebula M16 and produced the iconic “Pillars of Creation” image shown above. This was obtained with the narrow band filters SII, H-alpha and OIII. The tremendous public response to the release of this image was so overwhelming, it changed everything from the standpoint of how the space science community would handle the HST data and created a new philosophy toward how to deal with it. It became necessary to understand and explore further how color schemes could be used to show depth, motion and texture in an astronomical object. Furthermore once it was realized how this image and others like it could inspire the public and generate enthusiasm for astronomy in general, resources had to be allocated to processing and presenting these images for the lay public. For that reason the “Hubble Heritage” project was created which consisted of a team of both scientists and I believe at least 1 amateur astronomer. A 2005 paper was published for the Astrophysical Journal entitled “Image-Processing Techniques for the Creation of Presentation-Quality Astronomical Images” (Rector, et al) for the sole purpose of demonstrating how to generate color images from Hubble’s data. It might be the only professional scientific paper that doesn’t have even a single differential equation in it! This is a fascinating read and for those of you doing any image processing it even goes into some detail how to use Photoshop in its’ early days for combining and enhancing color images, and even how to use “clone and stamp” to remove star blooms! Since 2005 there has been an explosion of image processing software. The PDF article can be downloaded here.
Of course with this being a scientific article, the concept of color and how to represent it had to be “scientific” as well, rather than simply concluding “this color looks good” etc. As it turns out Isaac Newton bails them out because he is the discoverer of the color wheel!

“Color is parameterized … in an “HSV” colorspace wherein a specific color
is defined by its hue, saturation and value. “Hue” describes the actual color, e.g., yellow
or yellow-green. “Saturation,” also often referred to as intensity, is a measure of a color’s
purity. A purely desaturated color is mixed with an equal amount of its “complementary”
color. Drawing a line across the color wheel from a color, through the center of the wheel, to the color on the direct opposite side of the wheel defines a color’s complement. For example, purple is the complement of yellow. A purely saturated color contains none of its complement. ”Value” is a measure of the lightness of a color, i.e., the amount of white or black added. Other terms used to modify color are ”tint” and ”tone.” A ”tint” is a color with added white; e.g., pink is a tint of red. A ”tone” is a color with added gray and a ”shade” is a color with added black.(Rector et al 2005)
Furthermore “In general a good starting strategy when assigning color is to space the color assignments evenly around the color wheel; e.g., if creating an image with three datasets, assign undiluted colors that are 120 degrees apart on the color wheel. This is known as a triadic color scheme and is the simplest example of hue contrast”.(Rector et al 2005)

The challenge was to come up with a scheme or approach to the situation where color is not obtained through the usual optical broadband red, green, blue filters to produce a “natural” color image. This resulted in the term “false color” or “representative color” being used.
The best explanation of the “scientific approach” cannot be better stated than in this excerpt from the Rector article:

“An example of an image produced using the chromatic ordering scheme is the Hester &
Scowen (1995) HST image of M16. The data (Hester & Scowen 1995) were obtained with
the HST WFPC2 camera with the F502N ([OIII] _5012_A), F656N (Halpha _6564_A) and F673N ([SII] _6732_A) narrowband filters. To generate the image, the three datasets were colorized blue, green and red respectively. Filter F502N was assigned blue because it has the shortest wavelength passband,filter F673N was assigned red because it has the longest wavelength passband, and filter F656N was assigned green because its passband is of intermediate wave-length compared to the other two. The chromatic ordering for the HST M16 image is not a natural color scheme because the filters were not assigned their visible colors. That is, when viewed against a bright, white light, the F502N filter appears to be green, not blue, to the human eye. Similarly, the F656N filter looks a deep red, not green. Only the F673N filter is assigned its perceived color, red. It is also not a natural color scheme because it uses narrow-band filters that pass only a very small fraction of the visible spectrum. Furthermore, rather than photometrically calibrating the projected images they are balanced so that the H-alpha data doesn’t dominate and turn the image completely green. In comparison, a natural color image of M16 (Shoening 1973) shows the nebula as deep red, again because of the strong H_alpha emission from the nebula. The color assignment chosen is an extreme version of the hue contrast. The image is also an example of a split complementary color scheme. The blue (from the [OIII]filter) and the green (from the H_ alpha filter) combine to generate a background of greenish-cyan, whose complement is a slightly-red orange. Areas of the pillars are yellow-orange and orange-red which are on either side of this orange on the color wheel, hence the complement is split.
Also the RGB assignment to each layer, along with the intensity stretches, ensured that
the combined datasets produced cyan, magenta and yellow, resulting in a strong contrast
of hue in the undiluted primaries of the subtractive system. Where the intensity of [OIII]
(blue) and H_ (green) are balanced, cyan appears in the background. The H_ (green) and
[SII] (red) images combine to produce yellow along the edge of the pillars. And, while the
center of the stars are white due to the equal combination of RGB, their halos are magenta because the F673N filter broadens the point-spread function. Itten (1990), in his section on this contrast of hue states, the undiluted primaries and secondaries always have a character of aboriginal cosmic splendor as well as of concrete actuality,” a statement that applies to the HST image of M16. The two supporting contrasts, (split) complementary and light-dark further boost this image’s appeal.”

Well basically what I take from that is you assign your Red-Green-Blue in the order of wavelength of your filter band-passes meaning SII, longest wavelength goes to red, H_alpha goes to green and OIII goes to blue. This is the basis of the so-called Hubble Palette or “S-H-O” and this approach has since trickled down to the greater amateur astroimaging community! Who said that astroimaging is not science!

Next time I will show a recent example from my first ever attempt at processing an “S-H-O” image.
Thanks for reading!

Dr Dave

The Straight and “Narrow” Path: Narrow band imaging part 1

We begin the first part of a 3-part blog series on the subject of narrow band astro-imaging. Today’s discussion is more general on the topic and principles. The subject of color in the universe is frankly loaded with controversy. Many are convinced we have no idea what the true color of a deep space object is from our perspective here on Earth. If you have been to a star party and looked through a telescope of the Orion nebula what do you see? You see a green glow if it’s dark enough. You certainly don’t see the bright magenta and pink-red colors that just about every image of the Orion nebula portrays. This is because the eye is pretty useless as a color detector at night. What you can see from a nebula is likely to be greenish because that is what the eye is most sensitive to. The color receptors in the retina called “cones” are mostly inoperative at night. That doesn’t mean the colors aren’t there. For the most part it seems that those of us who spend a lot of time imaging the cosmos and having done so over the last 15-20 years have been able to come to a general consensus regarding the appearance of certain deep space objects when imaged using standard digital methods. By that I mean for a color image you are doing essentially the same thing you do when taking a picture of your family for example with a smart phone. Inside the camera is an array of red, green and blue filters which when combined gives you a color image . By terrestrial criteria, the colors are “real”. The sky is blue, a pine tree has a deep forest green color, a typical tomato is red, etc. When applied to astronomical objects you can use the same digital camera which has the filter array as mentioned or you can use a ccd or cmos sensor with separate filters and combine the greyscale images into a single color image. When you do that you see that emission nebulae are a reddish color, reflection nebulae are blue, galaxies have a soft yellow core with rust colored dust lanes and some have areas of active star formation which are reddish pink. This is pretty consistent and is true for what I call standard “broad band” images.

Diagram from Astrodon.com, manufacturers of amateur “broadband” filters. Blue , green and red filters shown with their respective bandpasses each around 100 or so nanometers. Combined they span the visible wavelength range from 400 – 700 and produce a full color image. “Lum” stands for “luminance” and allows the visible wavelength data to be recorded all at once unfiltered.

In the usual case you have the red, green and blue filters each selecting a fairly broad region of the visible spectrum, about 1-200 nanometers and slightly overlapping. This produces your standard amateur astronomical image. An unfiltered image can also be taken which is the “luminance” image. Actually the luminance filter does filter out the infrared but allows all visible wavelengths to be recorded at one time. This image typically has the best signal with the least noise and can boost the image quality by adding this to the color image.

I think we are now pretty comfortable with what the approximate “accepted” colors are for most deep space objects using these methods. However, during the time we were settling into this comfort zone, out there in space the Hubble Space Telescope was also imaging the universe. While the standard “LRGB” methodology of combining red, green and blue filtered images with an “L” or unfiltered image having better signal to noise properties can work well for our small ground based amateur telescopes, the Hubble and the large professional ground based observatories can’t do this with scientific data. The reason is that broad band filtering results in the loss of wavelength-specific structural information. They have to image at very specific wavelengths with the goal of increasing contrast between areas of energy emission from an object and what is called the “emission continuum” or the background. As a result of excluding particular wavebands, image quality is actually improved. And so it was in the mid-late 1990’s the birth of “narrowband” imaging occurred, thanks to the Hubble telescope!

Diagram of the common narrow band filters: SII, H alpha, OIII. Courtesy of Starizona.com,

Instead of imaging through filters selecting 1-200 nm of spectral bandwidth, narrowband filters only allow a few nanometers of light to pass through. These filters are as a result detecting very specific wavelengths of light which is typically emitted by gases in space. The most common elements that emit this light are hydrogen and oxygen. Sulfur is also fairly abundant. This is why hydrogen alpha filters which transmit light from atomic hydrogen at 656.3 nanometers, sulfur II which transmits the deep red light emitted by singly ionized sulfur and oxygen III transmitting the green-blue wavelength of 500.7nm, are the 3 most commonly used filters for narrowband imaging.
Next time we discuss the iconic Hubble image that changed the way both professionals and amateurs approach color and more on the narrowband imaging concepts.
Thanks for reading!
DrDave

Itsy bitsy spider

Alright, not so “itsy bitsy”. Located in the constellation Auriga, IC417, also known as the “spider nebula”is a hydrogen gas region which absorbs energy from massive hot stars in the vicinity, then re-emits that energy as light in the hydrogen alpha wavelength i.e. red light. The region measures about 100 light years across at a distance of 10,000 light years. This image from the 16” telescope was taken through hydrogen alpha filter only so it highlights the emission components of the gas cloud in a single monochrome channel. It is not as often imaged and has a very low surface brightness. Consequently the other commonly used “narrow band” filters, SII (sulphur) and OIII (oxygen) yielded hardly any signal at all when I tried them for this target, so I decided to pass on those additions.

The designation “IC” for the catalog number stands for “Index Catalog of Nebulae and Clusters of Stars”. Published in 2 parts in the late 19th and early 20th century, this was a supplement to the well known “NGC” or New General Catalog of extended objects (galaxies, nebulae etc). The IC catalog contains over 5000 objects in it!

What was interesting to me for this project was the name “spider nebula”. I was curious to discover where was the “spider” in the image. Some wider field views of this also contain a “fly” component supposedly. Amateur astronomers, perhaps like the ancients who named constellations or many of us who look at clouds and claim to see a cow or an elephant, have given many of these nebulae similar likenesses. These supercede any catalog designation: the jellyfish nebula (IC 443), the running chicken (IC 2944), the witch head nebula (IC 2118), the horsehead nebula (IC 434). You get the idea. So I looked at this image again after final processing and in this orientation I believe I see the spider! You can certainly let me know if I’m way off but I don’t see any other features that would resemble anything close to a spider or any other creature 🙂

IC 417, the “spider” nebula. Compare to the top image to see the unedited features!

Thanks for reading!

DrDave

 

Our place in the universe

Illustration of what this area looks like from up in Mayhill NM. Reproduced from the application Stellarium  to recreate as closely as possible what is seen with the naked eye. The edge on view of our galaxy’s core extends from the bottom of the teapot in Saggitarius and extends all the way past Antares which is a great landmark visually. Antares is in the constellation Scorpius . That constellation always reminds me of a lawn chair. Antares is at the foot of the chair. “CB” or the Central Bulge as it is referred to in drawings is at the head of the chair.

As we get closer to summer, the most glorious region of the night sky as seen from the Northern Hemisphere becomes visible and that is the southern portion of the Milky Way. Looking south now about 2-3 am what you see is illustrated above. It is important to note that when we do this we are looking toward the center of our own galaxy from one of the outer arms. A favorite activity of mine is binocular observing in this region. You could spend weeks doing that!

Just above Antares is one of the most colorful regions of the Milky Way band. The Rho Ophiuchi cloud complex is a dark nebula of gas and dust that is located 1° south of the star ρ Ophiuchi of the constellation Ophiuchus, just above Saggitarius. It is one of the closest star-forming regions to the Solar System, about 360 light years away. This wonderful wide field image was captured by Rick Young, who has an observatory not far from mine and does a lot of nightscape photography as well

 

On to “our place in the universe”!

Our Milky Way galaxy, the one we live in, is a spiral galaxy measuring about 120,000 light years in diameter and contains about 200 billion stars! The galaxy is a disc, so you can imagine living inside of a dinner plate and we are kind of on the outer rim of the plate. Earth is actually about 27,000 light years from the center (1 light year = 6 trillion miles). So imagine you are inside of the plate. If you look either upward or downward you would be looking out of the plate, away from it, where it would be much less dense and as a result you are going to see less stars. Now if you try to look from inside the plate toward the center of plate you are looking into a region of high density and you are going to see more stars as well as a lot of dust contained within the galaxy’s disc. This is why we are seeing what we see when we look through the disc or “band” of the Milky Way.

We are inside of this plate looking along the plane of the disc and this is why we see the Milky Way as we do

Southern Milky Way band on a clear summer night. We are looking through the plane of the galaxy’s disc just like being inside of the plate above!

 

On a final note, it was only close to 100  years ago that the astronomer Edwin Hubble first determined that our Milky Way galaxy was not the only galaxy in the universe! Of course now we know it’s only one of billions! See this fascinating APOD (Astronomy Picture of the Day) entry for more on Hubble’s discovery. Make sure to look at the April 26, 2020 entry. The link above will only take you to that days’ image whatever day you are looking at it so you will have to go to the archive page to find it if you are doing this after April 26.

Mount Wilson Observatory in Pasadena CA was home to the largest telescope in the world from 1917 until 1949. The Hooker 100″ reflector owned that title until the 200″ telescope at Mt Palomar was completed. During the early part of the 20th century many of the world-renowned scientists and astronomers went to Mt Wilson to conduct research there. Einstein, Hubble and several others were all there. This is where Hubble figured out our galaxy was not alone!

In the summer of 2003, I had the good fortune to be able to spend 2 weeks at Mt Wilson where I did a spectroscopy project. In the basement of the observatory housing the Hooker 100″ telescope were the lockers of the scientists but it was very dark when I tried to take this picture of Edwin Hubble’s locker!

 

Thanks for reading!

DrDave

 

 

News from Orion’s Belt

This is the April 2020 installment of current events at Orion’s Belt Remote Observatory, Mayhill, NM.

Routine maintenance on Pier 2 mount. The Paramount MX+ mount gets a “grease change”. This is recommended every year “or so” depending on usage. I usually go closer to 1.5 years. The procedure for this mount is not too complex. The worm block covers on both axes are removed allowing ready access to the gears. You then remove the old grease with a tooth brush and towel and reapply the grease to the gears by hand while manually rotating the mount axis you are working on to gain access to the entire gear. A detailed video is available on the Software Bisque website.

“Pier 2” operates the wide field equipment which includes currently the Takahashi 180ED scope. Shown here is the underside of the declination worm block assembly on the Paramount MX+ and this is the worm block cover.

Once you remove the worm block cover, then the next step is to remove the worm block which houses the worm gear. There are 2 cables which have to be disconnected. One shown here connects to the homing sensor and the other not shown connects the declination motor to the circuit board

 

Current imaging projects:

1. It is “galaxy season” as discussed in an earlier post and that means that Pier 1 (RiDK 400mm or 16″ scope) has to get busy! We are working on 2 targets now.

This is a single raw luminance image of M101, also known as the “Pinwheel Galaxy”. It is a very large galaxy with diameter of 170,000 light years. Our galaxy is 100,000 by comparison. One of the unique features of this galaxy that hopefully we can demonstrate when the project is completed is the high density of what are known as “HII” regions. An H II region or HII region is a region of interstellar atomic hydrogen that is ionized. It is typically a cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds of light years, and density from a few to about a million particles per cubic cm. These will show up as bright red areas in the spiral arms of the galaxy. In fact some of these are so prominent they have their own NGC catalog numbers!

Our second galaxy project is M104, the “Sombrero”. This is another single luminance image. This has been an elusive target for me probably because of its low altitude. It reaches just above 40 degrees at maximum altitude from this location which means the seeing has to be better than usual at the very least. Thankfully this year I have had better luck with that so it looks like it will finally happen! The compelling nature of the thick but intricate dust lanes encircling the bright bulbous core makes this a must target on anyone’s list! The Sombrero is actually part of the Virgo Galaxy Cluster and has a rich system of globular star clusters within it, about 2000 of them.

2. The current target for the wide field platform is NGC 6823, an open cluster and emission nebula in the constellation Vulpecula. This object doesn’t become visible until around 2 am but it should be a great target for the Tak180!

NGC 6823 with emission nebula SH2-86 in Vulpecula. Single 10 min H-alpha image with Tak 180 ED. Probably this is going to be an “SHO” image taken through the 3 narrow band filters H-alpha, OIII (oxygen) and SII (Sulfur)

 

Finally we briefly discuss new efforts being undertaken at the observatory for pest control! Those of us operating remote observatories all have to deal with some aspect of that. Fortunately for me I do not have a problem with mice (yet). We are coming up on 4 years since the observatory was built so perhaps that won’t be a problem here. What I do have is a significant miller moth infestation. They apparently are nesting inside of the roof motor! The first year of operation I was seriously startled when upon opening the roof about 1-200 flew out of there! The next year they decided to move into the 16″ telescope and a similar thing happened when I removed the cloth cover of the scope. While they did get into the housing behind the primary mirror there was no moth residue on the mirror itself. Also thankfully they did not take up residence inside any of the cameras. I ran the mirror fans for a day or so to get rid of as many as possible. So this year we have a new approach to this and we will see if this strategy will work:

1. No covers on the 16″ scope ever. I have a brand new set of mirror shutters which is an upgrade from the originally purchased ones. They never worked that well to begin with and now that I have seen what covering the scope can do for the moth problem I decided not to install them.
2. Moth traps. I tried these last year but unfortunately got it started after the moths hatched, but they do seem to work. These are cardboard containers coated with a resin that supposedly attracts the moths. Each container can collect up to about 30 of them!
3. Continuous airflow directed at the nesting site which in this case is the motor. I installed a simple fan that I can turn on and off remotely and leave it on all of the time until I open for an observing session.

This is the culprit right here. The Moth Motel! I don’t know how 200 moths can live in this but they do

These are the moth traps. I have about 20 or so scattered throughout both the observing area and the warm room. They are available on Amazon of course!

Fan installed in between the 2 piers but well out of the way and directed toward the roof and roof motor. I believe the constant airflow should be a deterrent to nesting.

So far I have not seen any moths but it is probably way too early. We should know in a couple of months if this is going to work or not!

Ok folks. That’s it for now. From astronomy to pest control, you read it all right here!

Thanks for reading!’

DrDave

Morning coffee edition- planetary trifecta!

We have occasional “Morning coffee” spots as I call them devoted to visual events occurring in the pre-dawn sky that are easily seen without any optical aids. When I have occasion to be up at the observatory for a few days or a week or so I don’t miss the opportunity to enjoy the dark sky out on the deck overlooking the valley.

At the base of the observatory site is what I call “astronomers living quarters”. The deck you see here has a view to the South but does span from east to west and is the “platform” for early morning viewing before dawn. Of course any time it’s dark is a good time! Naked eye viewing or binocular viewing are the most common. Occasionally I’ll get one of my small refractors out there.

About 4:30 am MDT looking toward the south – southeast was the expected waning moon, now just a tad under last quarter. Not expected at the time was a trio of naked eye planets from west to east, brightest to dimmest: Jupiter, Saturn and Mars. All were seen within about a 15-20 degree field of view approximately!

The waning moon accompanied by Mars, Saturn and Jupiter above at around 4:30 MDT. Sagittarius the “teapot” is the constellation to the right

Just an iPhone image! Much better viewed with the naked eye.

Thanks for reading!

DrDave