Markarian's Chain

The Minnesota Astronomical Society (MAS) has sponsored Messier Marathons for many years. Recently they've begun holding the marathon twice a year by adding a fall gathering for what's called the mini-marathon.

The spring marathon gives everyone a long, good look at the Virgo cluster of galaxies, home to 16 Messier Objects. There are more than just Messier galaxies in the cluster and deciding which particular faint fuzzy you see in your eyepiece can be difficult. Navigating the Virgo cluster is difficult for anyone who hasn't done it frequently.

Beginners wander into the cluster not just during marathons but also when working on their Messier lists. It's not unusual for them to leave the cluster with a sense of frustration.

With that frustration in mind the MAS started what it calls the Virgo Venture, a spring evening during which all attention is on the cluster and learning how to navigate it. Special star-hopping charts are provided and there's an experienced navigator around to help observers find their way.

It was at one of these Ventures that I first observed Markarian's Chain, a gentle arc of galaxies in a small patch of sky. It was the first time that I'd seen more than two galaxies in the same field of view. In fact, I could count six, and with a little travel add a few more! I was impressed, and it marked a first appreciation of wide field viewing for me.

This year's Venture was held last Saturday despite thinning cirrus clouds running east-west over the site and a thick plume of smoke from Canadian wildfires. My imaging target was the Chain but given the overhead murk I didn't have a lot of hope. I shot an hour of light frames with the haze and another hour as the haze was disappearing, so it didn't turn out too badly.

The entire group of galaxies fits tightly in the 700mm view of a TV-102 with its focal reducer/flattener in place:

Markarian's Chain, stretching from the two fuzzies in the upper left corner to M84 near the right edge.

The acquisition details are at AstroBin. Briefly this is two hours of light frames using a modified Canon T2i at ISO 800, a TV-102 at f/7, and autoguiding.

The weather forecast suggests a week of clouds and then the moon comes back. A good cycle to do some lunar/planetary imaging, I suppose. June's new moon will bring a last shot at many Arp galaxies, and then it's summer and back to nebulae!

Messier Marathon Night Results

"Mission Accomplished!" to use a cliched phrase. "Goal Reached" might be a little better, or maybe "Dumbness Overcome."

This was one of my first attempts to use my DSLR in quite a while, and I managed to make a lot of mistakes early on:

• Forgetting to return to ISO 1600 from the composing setting of 6400
• Forgetting to set the shutter control to bulb
• Forgetting to increase the number of frames on the DSLR controller from the dark frame to light frame counts

And so on. The evening began with starts and restarts, but once it got going it went well. The time I lost meant I wouldn't go after the dimmer planetary nebula I had included on my object list in the last post, but that was okay.

All the hardware worked perfectly, although some went untested. The dry air and the gusty to breezy conditions meant the dew preventers weren't needed. It was only around 2 A.M. that frost began to appear, and my scopes stayed clean until the end a little before 3 A.M. The DSLR power supply worked perfectly and the 35Ah battery was barely tested running that and the mount. I used my laptop for PHD with its power supplied by it's own battery augmented with a Duracell 600 battery pack. The Duracell ran down pretty far in the five or so hours, so this might not be a good option for multi-night imaging. For more power conservation I need to find a way to turn off the laptop's display, not simply dim it.

The evening tally was six Arp galaxies and one planetary. In terms of Messier objects it was 9 1/2. Let's see some marathon images:

Leo Triplet (clockwise from NGC 3526 at top, M65, and M66) Together these are Arp 317. M66 is Arp 16.

M49 (right of center, Arp 134)

M60 (left of center, Arp 116) and M59 (right of center)

M87 (Arp 152)

M90 (Arp 76) and M89 at bottom edge

M97 (Owl Nebula) and M108 at bottom edge

All the images are based on 10 three minute exposures with a Canon T2i (at ISO 1600) riding on a TV 102 operating at f/7--except the image of M90, which was 5 three minute exposures at ISO 6400 (see list of mistakes above). These were calibrated with 20 dark frames collected throughout the night as the temperature fell from around 30°to 20°F. They obviously haven't been flatted. I reprocessed them to include synthetic flattening, and now they look a lot nicer!



An inspection of single light frames shows that they surpass visual observations, so why not bring back the idea of an Imaging Messier Marathon? Three minutes at ISO 1600 is about the same as 45 seconds at ISO 6400. 3/4 minute times 110 objects is only 82 minutes; out of a six hour marathon night that leaves four and a half hours for acquisition and composing images. Definitely doable.

That aside, the evening bumped my Arp list count to 26 and my planetary list count to 23. Both lists are about 1/4 done!

Onward to warmer weather!

Messier Marathon Plans

Tomorrow night is Messier Marathon night and it looks like it may actually be clear!

Considering what we often see for the MM, this will be relatively balmy (wind chills in the teens above zero) and dry (the observing field is a little mushy, but there's no snow). It helps that this year it's being held in April even if that's not best for getting a high count.

Having gone over to the imaging side, that's what I'll be doing. To keep in the spirit of things I'll do mostly Messier objects.

Because the Ms are fairly bright I'll be using my DSLR. The targets will be taken from the two Astronomical League lists I'm working on, Arp galaxies and planetary nebulae.

Here's the list, Galaxies first:

• M49
• M60
• M65
• M66
• M87
• M90

These all have surface brightness between magnitude 21.3 and 22.3, so I think they can be imaged fairly quickly for modest quality results; it is a marathon night. Because M65/M66 occupy the same field of a TV-102 and DSLR, they require only one image. So for the six galaxies I'm expecting four to five hours of clock time including time for acquisition, composition and dark frames.

Next the planetaries and their surface brightnesses:

• M97 (22.3)
• Abell 21 (24.9)
• Abell 36 (25.5)
• Abell 35 (26.2)
• PN G164.8+31.1 (26.6)

You can see why the last four are not Messier objects; they're not very easy to see. Abell 21 is about three times larger than M97, making it a good target for the relatively short focal length TV-102 (700mm). Given its location in Gemini it might be the evening's first object and will get up to two hours of photons. The other dimmer objects will probably get passed over.

Messier Marathon Night

The MM was something of a bust this year. Instead of bitter wind chills or an observing field buried under a foot of snow, conditions were actually quite pleasant. But there were those clouds. Patches of opaque clouds gave way shortly after nightfall to a succession of semitransparent bands that simply wouldn't stop obscuring large chunks of the sky. For the most part I could shoot through the clouds, but visual observers were shut out of all but open clusters and the brightest nebulae and galaxies. 

Seeing was suggested to be poor, too. And then there was the wind. Southerly and modest at first, as a cold front passes they turned and gusted to almost 30 miles per hour. My autoguider struggled but held its own against this for the most part--a few frames had to be dropped because of poor tracking. 

I started the evening with thoughts of doing some MM work myself, but conditions ended that possibility. Instead I concentrated on imaging the brighter winter objects of the ALBN. 

The updated winter list (earlier images in green, MM night objects in red):

January: IC 2169, LBN 943, Sh 2-280, NGC 2296, IC 468, NGC 2359
February:
November: IC 360, NGC 1555, NGC 1579
December: LBN 945, NGC 1931, Sh 2-264, NGC 1999, Sh 2-240, LBN 962, NGC 2149, NGC 2174, IC 2162

This is the end of any chance to get more winter objects unless the skies clear quickly. Still, this winter netted eleven objects, leaving me at an ALBN list count of 87 done, 13 to go. Next up are some large LBNs that will test my still unused 200mm Olympus lens. LBN 1088 (200mm); a combo shot of LBN 1089 and 1090 (135mm), then another 200mm combo of LBNs 89 and 90.

From MM night, all taken using a TV-102, ST-8300M camera shooting luminance frames:

A combo image, the Cone and Hubble's Variable Nebula--

Cone and Hubble's Variable Nebulae

The effect of clouds is evident around 15 Mon (the bright star at top of image). Despite that the cone and Hubble are evident. Next is the Monkey Head--

NGC 2174 (Monkey Head)

Can't see the "Monkey?" It's more evident when shown south-upward instead of north-up as in this image. Some clouds here, too; the glow around 68 Ori (at lower left) is theirs.

Last, NGC 1931 (which is nameless, so far as I know)--

NGC 1931

Still some cloud effects. This deserved a longer focal length, but I wasn't about to swap telescopes at midnight at a remote site. An eventual overcast forced me to stop this sooner than I wanted.

I packed up and left the field at 1:23. I was the last to leave, which tells you what sort of MM it was. A nice get-together, a good no-pressure night for some of the club's beginners, some so-so imaging, and a spectacular fireball that lit up the sky. All of which were better than a -25F wind chill.

Imaging Messier Marathon

A plan is being hatched here for an Imaging Messier Marathon or IMM. Just as with the regular visual MM this is all about quantity, not quality.

I have an secondary motive for doing this. I am co-owner of a small (if it was any smaller I'd be the sole owner and employee!) that creates educational software for the earth sciences. One program is an astronomy package, and I'd like to use my images to populate a photo gallery of common objects.

But this isn't about putting together a lot of images for students to ooh and aah over. Nothing I do can compare to what other imagers create, much less resemble something like a HST image.  My goal is to show them what the Ms look like through a small telescope--say a 6" or 8" Dob. I don't want them to be disappointed at the fact that faint fuzzies usually look just like that until you either use a large telescope or view from a really dark site. Sadly, most kids (and teachers) don't have access to either.

I know from experience that showing them the planets (particularly Saturn, Jupiter, crescent Venus and Mars at opposition) and the Moon can really wow them. But often it's the case that they expect galaxies to be just like those bright, colorful spirals seen on the Internet. Sometimes they can't even find a galaxy or globular in the field of view because they're looking for something much more spectacular.

So my goal is to produce a set of images that give teachers and kids an idea of what something will look like in a small telescope operating under a suburban canopy of light. A few of the images will be accompanied by better images, when I'm able to take them.

This means for most objects I would shoot a handful of light frames. Even though most galaxies and nebula show no color visually, I would probably shoot everything with the same scheme: 30 second exposures, binned 2x2, maybe three frames each of RGB, using my ST8300 and TV102. No autoguiding, and only a simple polar align.

Detailed resolution won't be important because untrained eyes have a hard time picking that out, and colors can be muted at best. Quantity, not quality.

As an act of faith that it will eventually be clear at night, I mailed in my registration for Wisconsin Observer's Weekend. Hooray!

Messier Marathon plans

The Minnesota Astronomical Society's springtime Messier Marathon is scheduled for a night I'm teaching. How could it be any other way? (If that night is cloudy and the next night is clear it will be held then.)

I've tried my hand at the marathon. some years ago--2004, perhaps?--I gave this a try and got 93 by starhopping. That was a long, cold night, but very calm and clear. It was a "fun-once" sort of thing, and I doubt I'll try it again anytime soon.
Instead, my mission for that evening is not racking up Ms, but instead to image them. Imaging with a difference, however. The intent is to create images that replicate how the objects look in modest telescopes (6 or 8 inches in objective diameter). These will really require very few light frames, and since the eye can't really see color, they can be simple luminance exposures, and fairly short ones at that.. During the course of an evening I should be able to image quite a few!

These are intended for the next release of my astronomy software, RSI New Moon.