Category Archives: Observing Log

Posts describing an observing session or astrophotography session.

Eskimo Nebula – 2015-03-23

Eskimo (Clown) Nebula (NGC 2392, Caldwell 39)
Taken 2015-03-23, 21:00 to 23:30edt

Eskimo Nebula - Full Frame - 2015-03-23

Eskimo Nebula – Full Frame – 2015-03-23

This is a planetary nebula called the Eskimo Nebula or sometimes Clown Face Nebula. Planetary nebulas get their name because they appeared to early telescope observers like giant planets. They are actually an expanding shell of ionized gas ejected from a catastrophic event in the late stages of medium to small star’s life. (Contrast this to supernova for giant stars.) The Eskimo nebula actually has two shells of expanding gas which gives it an unusual appearance.

Distance 3000 light years
Apparent mag 9.1
Central star mag 10.5
Visual Size 48 x 48 arc-sec

A closer crop and up-sampled 2x is easier to look at, but does not show any more detail:

Eskimo Nebula - - Crop - 2015-03-23

Eskimo Nebula – – Crop – 2015-03-23

Celestron HD11
Canon T2i with Astrondon uv/ir filter inside
Guided with Celstron OAG, Chameleon and Metaguide

HDR at ISO1600
– – 15 x 120s
– – 7 x 180s
– – 18 x 240s
– total integration 2hrs

Venus and Mercury – 2015-05-06

Mercury

Mercury was at its greatest elongation for 2015 om May 6th at 21deg, so i decided to try to capture an image of it. Being low in the sky it’s hard to get a clear view through the murky unstable surface air. So i decided to capture the image just after sunset at 20:19edt when it was still relatively high. Mercury was not yet visible unaided, but it showed up well in the telescope. The sun had just set at 20:16 when i captured the image, so it was only 0.5deg below the horizon. Nautical dusk wasn’t until 21:31. The down side was the bright evening sky reduced contrast. Given it’s very difficult or unusual to resolve any surface details of Mercury in a backyard telescope, the lack of contrast wasn’t going to matter.

Mercury 2015-05-06, 20-19edt

Mercury 2015-05-06, 20-19edt, Monochrome

Being only 7.9″ in angular size, it is very difficult to resolve any surface details at the best of times. And being so low in the sky and taken only minutes after sunset, the unstable surface air and low contrast obscured what details might be obtainable. The only interesting feature then is the phase. Mercury is also grey, like the moon, so a colour image wouldn’t actually have any colour.

I used the Celestron HD11 with a 5x Powermate. The effective focal length is therefore 14,000mm at effectively f/50. I capture a 60sec AVI (movie) at a resolution of 640×480 at 30fps with a monochrome Point Grey Chameleon (no filters). That works out to 1792 frames. Using Autostakkert2, i selected the best 10% of the frames and stacked them into a single image. Further processing with PixInsight (wavelets and curves) sharpened up the edges to reveal a nice waxing crescent – but no surface detail.

The specs for Mercury that evening were:

  • Mag: +0.4
  • Size: 7.9 arcsec
  • Illumination: 38%
  • Azimuth: 286deg
  • Altitude: 18deg
  • Elongation from Sun: 21deg (at maximum)

I tried using a 35nm IR pass filter with the above setup, but at f/50, there wasn’t enough light. The advantage of using IR is it less affected by the turbulent air and the narrow bandwidth improves focus. A future project is to try the IR filter with the HD11 at prime focal length or with a 2x powermate.

Venus

Venus was at a greater elongation [from the sun] so i waited until 21:04edt to capture that image. The sun was now 7.5deg below the horizon and closer to nautical dusk (21:31).

Using the same technique above, i captured two 60sec AVIs and processed them with the same method. Then i combined the two resulting images which reduced some blotches.

Venus 2015-05-06, 21:04edt

Venus 2015-05-06, 21:04edt, Monochome

Venus is blanketed by a thick white cloud, but unlike Jupiter and Saturn, there is no colour or banding visible in white light. (I have seen some images in UV that do show some some cloud details.) So even though Venus is a reasonable 18arcsec in angular size, the only interesting feature is the phase.

The specs for Venus that evening were:

  • Mag: -4.14
  • Size: 18 arcsec
  • Illumination: 64%
  • Azimuth: 280deg
  • Altitude: 28deg
  • Elongation from Sun: 43deg (maximum is 45deg)

Venus and Mercury Comparison

Since i had the two images created with the same gear, i decided to display them side by side to show the relative angular sizes:

Venus and Mercury 2015-05-06

Venus and Mercury 2015-05-06

 

Examples of What Other People Can Do

While it’s difficult to get images that show any detail on either Mercury or Venus, it is possible to capture images using relatively modest ground based equipment (not billion dollar mountain top scope). The links below to Daniele Gasparri’s web site [external link] show some impressive images that have been acquired using a C14 combined with various filters.


Mercury by Daniele Gasparri [External Link}


Venus by Daniele Gasparri [External Link}

Micro Moon – 2015-03-05

To complement the “Super” moon of September 9th, 2014, the moon was at it smallest for 2015 on March 5th. The conditions were almost just as good as in September 2014, so i managed to capture a view of the apogee full moon (furthest away) that was almost indistinguishable from the Super moon expect that it was 10% smaller.

Micro Moon - 15.14days - 2015-03-05

Micro Moon – 15.14days – 2015-03-05

Images of Comet c/2104 Q2 (Lovejoy) – 2015-01-19

Using a Stellavue 80mm APO (with 0.8x reducer) and a Canon T2i, i took some images of comet Lovejoy. The main imaging run was 30 x 2 min exposures at ISO1600. The comet is bright enough that the core is blown at this exposure. So i also took a series of shorter exposure sets at 60s, 30s and 15s. Unfortunately, i could not create a high dynamic range image (HDR) with the short exposures – either automatically with the tools i have nor manually.

I was guiding on a star and not accounting for the relative motion of the comet. At 2 min expsoures, it’s manageable as the comet is not moving so fast that it would show any noticeable signs of being stretched in each frame. However, after an hour it had moved considerably in the FoV, so each frame had to be realigned to the comet’s new location. The 30 aligned frames were then stacked with a rejection filter. This provided the best image of the comet at the expense of dimming the background stars. (A simple averaging would keep each star and the result would be a line of stars giving the impression the comet was racing past them – which it is.)

Comet c2104 Q2 Lovejoy 2015-01-19 comet aligned

Comet c2104 Q2 Lovejoy 2015-01-19 comet aligned

The part of the tail visible in the image above is 2.2deg wide. This works out to 3.3Mkm in actual length and that’s not all the tail. The distance from earth to the comet was about 85 Mkm when the image was taken.

To get an image with the background stars, i reprocessed just 5 of the images and aligned on the stars. Even with a 10min lapsed time, the comet is still not stretched too much in the final image.

Comet c2104 Q2 Lovejoy 2015-01-19 star aligned

Comet c2104 Q2 Lovejoy 2015-01-19 star aligned

Comet c/2104 Q2 (Lovejoy) – 2015-01-15

A bright comet is moving through the solar system and in January is just getting bright enough to be visible unaided.

I managed to see Lovejoy unaided from my location just south of Carp at 10pm on January 15th. The light pollution map shows my location as orange, but it’s probably a little better than that looking south west where the comet was.

The comet was just visible with averted vision and occasionally while looking directly at it. With binoculars it was of course obvious, but no tail was detectable. With my 173mm, f/5.7 Dob, the core was very distinct within the larger halo. Still no tail.

For brightness comparison, Botein, Epsilon and Zeta Aries were also just visible – mag 4.34, 4.69 and 4.84. However 63 and 47 Aries – mag 5.09 and 5.78 – were not.

North America and Pelican Nebula – 2014-10-24

The region around the brightest star Deneb in the constellation Cygnus is occupied by a giant cloud of ionized molecular hydrogen (H II or H2) which is categorized as an “emission nebula”. Three degrees towards the north are two nebula named the “North America Nebula” (NGC 7000) and the “Pelican Nebula” (IC 5070).

NGC7000-IC5070 - North America and Pelican Nebulae - 2014-10-24 v1

NGC7000-IC5070 – North America and Pelican Nebulae – 2014-10-24 v1


The image spans 3.2 x 3.0 degrees which translates to an object size of 96 x 89 ly

The interesting  “North America” shape is caused by interstellar dust blocking some of the light from the nebula. Therefore the stars in the “”Gulf of Mexico” are in front of the dust and closer to us than the actual nebula. The peninsula is referred to as the “Cygnus Wall” and the bright filaments along the wall are regions of intense active star formation.

IC5070 - Pelican Nebula 2014-10-24 v3 high contrast

IC5070 – Pelican Nebula 2014-10-24 v3 high contrast


The Pelican nebula is supposed to look like a pelican taking flight. With the low contrast in my image it’s hard to make out. The pelican is facing towards us and to the left. The top of it’s head is the peak above the bright filament in the upper centre and it’s full beak is pointing down to the left and formed by the cloud along the upper left edge of the nebula. The vertical filament itself outlines the back of the pelican’s neck. The right part of the nebula is then the bird’s right wing on the downward part of a stroke. The left wing would be behind the pelican’s beak.

The pelican shows up better in the high contrast version of just IC 5070 (reprocessed from the same image above).

Generally emission nebula are difficult to see. Although quite large and bright in H-alpha, it is not possible to see this object unaided. The ionized hydrogen glows strongly deep red from the primary Blamer series Hα (hydrogen alpha) at 656nm. Unfortunately our night time vision (scotopic vision) tops out at 620nm, so we cannot see the Hα faint red glow. (Our day time vision – photopic vision – can see deep reds up to about 750nm when they are bright daylight intensities.) But the nebula also glows in other wavelengths so it is possible to see it.

There are some reports that the formation can be seen with binoculars or a small telescope using a UHC filter. I suspect this has to be done under dark skies and ideal conditions. I have never been able to make it out from my semi-rural location.

North America Nebula
– Magnitude: 4.0
– Angular Size: 120 x 100 arc-min
– Distance: 1,600 ly

Pelican Nebula
– Magnitude: 8.0
– Angular Size: 60 x 50 arm-min
– Distance: 1,800 ly

This is a two pane mosaic. The left part of the NA Nebula is from a data set acquired 2010-10-09 using a TV Pronto and Canon XS. The right side of the image, including a good portion of the NA nebula and all of the Pelican Nebula was acquired 2014-10-24 with a Stellarvue 80mm APO and a Canon T2i. The Pronto and SV80 have the same FL of 380mm, but the cameras are different so the image scales of the two sub-frames are different. The Pronto image was up-scaled to match the image scale of the Canon T2i and then aligned and merged to form the composite image.

Super Moon 2014-09-09

A “super moon” occurs when the moon is full (or new) and is also at it’s closest approach to the Earth (perigee). When this happens, the full moon appears bigger and brighter compared to other full moons. The difference in size is only 16% compared to the smallest full moon – a full moon at apogee or micro moon. So it’s actually very hard to notice the larger apparent size unless you see the super moon presented beside the micro moon.

While i don’t like the term “Super Moon” the media has latched onto it, so that’s what i’ve call this post. The correct term according to wikipedia is “perigee-syzygy of the Earth-Moon-Sun”. Ok, doesn’t roll off the tongue very well. But a simpler term is “perigee moon”. Perigee meaning the point where the moon is closest to earth during it’s monthly orbit. Both a full moon and new moon at perigee are considered a “super moon”, but the media doesn’t seem to care about the new moon event. (At new moon you can’t actually see the moon since it’s directly in line with the sun.)

When a full moon or new moon occurs, the sun, earth and moon are aligned so their mutual gravitational forces are also aligned and the combined affect on the earth’s oceans is at it’s greatest. At perigee the moon’s gravitational pull on the earth is also at a maximum. So the combined affect of the sun and the super moon can have a mild affect on tides. And if a perigee moon occurs in spring when tides are already at their highest, the additional affects of a perigee moon can be noticeable.

It’s always reported in the media that the perigee full moon makes the tides higher. But it occurs to me that at full moon, the moon and sun are on opposite sides of the earth. So it would seem their gravitational pull on the oceans should cancel out and the tides would therefore be smaller. I don’t know if this is the case however.

Usually there are 2, and occasionally just one perigee moon in a calendar year. The coincidence of full moon with perigee occurs every 13.94 months. The new moons before and after the full moon can also be at perigee so it’s possible to have 3 super moons in one calendar year. This occurred in 2014 with super moons on July 12th, August 10th, and Sept. 9th.

On September 8th, i took a photograph of the almost full moon just around sunset – or moon rise.

Super Moon 2014-09-07

Super Moon 2014-09-07

The next day was actually the super moon event and i took this photo:

Moon - Super Moon 2014-09-08 v2

Moon – Super Moon 2014-09-08 v2

M81-M82 – Bodes Nebula – 2014-04-24

The data for this image was collected in April but i didn’t get around to processing the image until last week. I was working through a new image processing workflow based on PixInsight. It didn’t really take 6 months to develop the process, it just took that long for me to get around to it.

Bode’s Nebula is in the constellation Ursa Major, and therefore towards the north. Until last year when the trees to the north came down, this target was out of view.

The data was aquired over three nights. However, there were a lot of technical problems (and operator error) so only 2 of the three nights produced usable results. And then only a partial set of the data from the other two nights was acceptable. Still, there is 5hrs of integration time which is enough to produce a reasonable image.

M81 (NGC 3031) Bode’s Galaxy
Face-on spiral galaxy in Ursa Major
Dimensions: 26.9 x 14.1 arc-min
Magnitude: 6.94
Distance: 11.8 mLy

M82 (NGC 3034) Cigar Galaxy
Edge-on spiral galaxy in Ursa Major
Dimensions: 11.2 x 4.3 arc-min
Magnitude: 8.41
Distance: 11.4-12.4 mLy

M81-M82 - Bodes Nebula - 2014-04-24

M81-M82 – Bodes Nebula – 2014-04-24

The bright star in the upper middle of M82 is a supernova SN 2014J which appeared 2014-01-21 at 19.20 UT. A close crop with an annotated view shows the location of the super nova.

M82 -SN 2014J - 2014-04-24

M82 -SN 2014J – 2014-04-24

NGC6946 – Fireworks Galaxy 2014-09-26 v2

The Fireworks Galaxy is technically in the constellation Cygnus, but it is quite a bit to the north. Until the trees were removed last year that obsecured the northern sky, circum polar objects were out of view.

NGC 6946 (Arp 29, Caldwell 12) – The Fireworks Galaxy.
Dimensions: 11.5 x 9.8 arcmin
Magnitude: 9.6
Distance: 22.5Mly (+/- 8Mly)

NGC 6946 - Fireworks Galaxy - 2014-09-26 v2

NGC 6946 – Fireworks Galaxy – 2014-09-26 v2

The data for the image was collected over three nights from Oct 24 to the 26th. Amazingly there were 3 clear night in a row all with good seeing. The total integration time is 15hrs which is a bit of a record for me.

Not Much Summer Astronomy Happening – 2014-07-09

The late sunset for a few weeks before and after the summer solstice means that any deep sky observing can’t even start ’till quite late. Therefore i tend to abandon any plans for serious observing in the late spring and summer. The early sunrises also reduce the available dark sky time, so photography is a bust. That, and using a DSLR means that the camera sensor is hot – like 25c – so long exposures are quite noisy. In Ottawa, astronomical twilight is as late as 11:30 with dawn around 2:30. Even in July the skies don’t really get dark until 10:30.

I have therefore taken to quite casual observing. Mostly this means taking in the few star and planets visible when i take the dog for a walk around 9pm. I might get out the binoculars but not usually.

In June, i did manage to see Saturn, Mars, Jupiter and Mercury in the evening sky – all at the same time. I was actually lucky enough to see this lineup on two or three nights.

Just this month, i saw the conjunction of Mars with the 2 quarter moon. I think they were less than 1 degree apart.

The summer constellations are coming into view – Scorpios and Sagittarius. The latter a little later in the evening right now. The centre of the milky way is just a little right of Sagittarius and therefore is the brightest and most prominent section. By late August and September the milky way will be at it’s best in the evening.

I plan to start some astrophotography projects perhaps in late August when the nights are cooler and the skies are darker at a more reasonable time.