Relative Planets

Evenings of July 6th through July 8th, 2018

The weather was amazing this weekend, especially for early July.  Clear skies, no humidity, and bugs only became a problem on the final night.

On Friday evening I took another set of Jupiter pictures.  These are not shown, as the following day’s images were far superior.

After Friday’s Jupiter session, I kept the telescope out after midnight, so technically on Saturday, to image Saturn for the first time this year.  As always, I have to wait for the planets to clear trees to the Southeast.  Since Saturn is now a few weeks past opposition, I get a clear few of the planet shortly after midnight.

For Saturn, I checked my written log for the settings I used last year (ISO 3200 and 100 exposure).  These, according to my log, gave me my best results.  But thinking I could do better based on my recent Jupiter work, I decided to try ISOs at 1600 and 800 and exposures of 60 and 30, respectively.  Lower ISO means less noise.  The results were not too bad, but I think the 3200/100 settings are still the best, and will try those next time.

On Saturday night, I took what I think may be my best Jupiter yet.  The finder focus on my first attempt was near perfect, if not perfect.  Look at the cloud band detail!  I only wish the Great Red Spot was facing us more at the time.  You can also see Io next to the GRS.

Then on Sunday I dragged my big telescope to my front lawn to capture Venus setting in the West.  This is the first time I did that.  The results were much better than I expected.  You cannot get much from Venus beyond its general shape.

What is neat about lining all three images side-by-side is that they were taken with the same telescope and same equipment setup, so you get a great sense of their relative sizes as seen from Earth.  Venus is noticeably smaller even though it is the closest to Earth and approximately the same size as Earth.  Right now, Venus is just over 90 million miles (145 million km) away.  Jupiter is about 450 million miles (724 million km) past, and Saturn is 840 million miles (1350 million km) from us.

What I should have done was take an image of a star, to show its relative size as well.  Next time!

Equipment used this weekend:

  • 254mm homemade Dobsonian
  • Canon EOS at prime focus
  • TeleVue x5 Barlow
  • Neodymium filter
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Saturn in July 2017

July 16th, 2017, 11:10 p.m. local time

All the recent rain and generally miserable humid summer weather almost made me forget that there was a brief pocket of pleasant evening clearness just this past Sunday.  It was a great opportunity to move my 10″ Dobsonian to my back deck for taking in the evening’s astronomical wonders.

I started with imaging Saturn, my primary objective.  I had great difficulty locating Saturn that night and it was almost 20 minutes before I locked on.  Keep in mind this is all a manual process.  My homemade Dobsonian is a Newtonian reflector on a simple alt-az swivel mount.  Even by turning my exposures all the way up, I still had problems finding it.  The lesson here is that it may be next to impossible to attempt imagining of Uranus in a few months with my meager equipment.

Returning to the present though with Saturn, I think this may be my best yet.  When I image the planets, I always take a few sets of videos with different refocusing.  It is really, really hard to get the exact focus right, and the digital camera’s view screen can only get you approximately there, hence the need to take a few sets so that hopefully at least one of them is good.

This night, I took two sets, and it was the first group of videos that allowed me to create the above image.  I also used my Neodymium filter, which I prefer for Saturn as it brings out a nice color contrast among planet’s cloud bands and ring levels.

After my Saturn session was complete, I put a 17mm eyepiece on the scope just to look around on that clear no-Moon night.  Of note was the Hercules Globular Cluster (Messier 13) which I saw clearer than I ever had.  Wow!  I could make out many bright stars in the foreground of the cluster.  I don’t have the proper equipment to image it, but I hope to have the skills to properly draw it by next year.

Also of note was that I am starting to see Cassiopeia earlier and earlier in the Northeast.  It’s the great pointer to the Andromeda Galaxy.  My view to the East is mostly blocked, so I have to wait some before the galaxy is visible via telescope and binoculars from my backyard, but it is comforting to know my favorite gray smudge will be back soon!

A Blazing Full Moon with Saturn

July 9th, 2017, 12:15 a.m. local time

This moon was full – very full.  And it was very bright.  The sky and everything were lit like alternative dawn imagined on an alien world, not by our Sun but from an unknown foreign star.  The Moon hiding behind a patch of clouds helped to illustrate this effect.

In the photo, you can also see Saturn off to the right.  The summer weather has stopped me from getting my telescope out more to both look at and image the planet, but I hope to get a least a few good sessions in through the month of July.

On a side note, my stargazing has been jagged for the past two weeks.  I packed it all in during the July 4th weekend while all the bombs were going off, for fear of a stray firework hitting either me or my telescope.  But I have also been studying the sky, to understand which constellations and stars are out this time of year.  My favorite, Scorpius, looms over the South horizon.  I have mapped out Bootes, which falls into the category of constellations not obvious to find unless you star hop and have a moderately dark sky.  Hercules and Ophiuchus are this type as well found in the Northern Hemisphere during the Summer.

What I am really looking forward to is the “return” of the Andromeda Galaxy.    We are nearly at that time of year again where I will be able to see it peeking over my East treeline if I stay out well past midnight.  According to my log I started viewing it last year mid-to-late July.

First Saturn of 2017

June 19th, 2017, 12:45 a.m. local time

It was a hasty session under non-ideal conditions, and I was very tired, but I wanted to try capturing Saturn with my 10″ Dobsonian and DSLR camera.  I have the Jupiter settings down fairly pat, so now it is time to start honing in on taking good pictures of the sixth planet.

A few factors became obvious when I started.  First, since Saturn is much lower towards the horizon, I am going to have to use my counterweights (a bunch of “C” clamps) to keep the Dobsonian from falling over with the camera attached.  For last night, I just held the tube up manually.  I only got about 1,100 shaky frames across back-to-back videos.

Next, it will be a challenge to get the ISO and exposures right, since Saturn is fainter than Jupiter.  With Jupiter, I could achieve focus by setting the camera’s option to overexposure and then focusing in on Jupiter’s moons.  Titan seems too faint for this focusing method to work.

Last, it is going to be a bit uncomfortable over the next month trying to photograph in Summer conditions.  I have come to love the Winter for stargazing – no bugs and you can just layer up.

Forecasted viewing is pretty bad for the rest of the week.  The only good news is that Saturn is still appearing a bit too late in the evening, as I must wait until after midnight to view it due to the tall Southeast obstructions in my way.  Hoefully things will look up in a few weeks.