NGC 2024, Flame Nebula

Unguided, 272 x 15 sec JPEG frames, 1600 ASA, and noise reduction enabled. Had a little trouble getting this one, but in the end it didn't turn out too bad. I appear to be having battery amp glow issues as of late. Not too sure what that's all about. Nights have been getting cooler, too. Strange. It has been more prominent lately. Thinking about charging ahead of time and letting the batteries refrigerate for a bit.

Eric, "supersize" has been restored

The friendly folks at Google recently made a change to Picasa regarding the embedded picture hotlinks. Currently, the embedded references constrain you to a few fixed viewing sizes and does not directly provide a link to the full-size JPEG that is stored there...like I used to be able to get.

I figured out how to bypass this. If you happen to notice the new links Picasa uses now, you'll find a size code inserted in the URL pathname. For example, the 288 pixel-wide view includes .../s288/... in the pathname. If you instead use .../s0/... for size zero, then apparently it defaults it to the full-size image stored there!

Programmers are so predictable.

So, all the 9 embedded links since that change in the Messier and NGC collections sidebar have been supersized, and I'll do so for all new pics.

Cheers, Eric. Thanks for letting me know you liked that feature.

Messier 1, Crab Nebula

Unguided 251 x 15 sec JPEG frames, 1600 ASA, noise reduction enabled. Always wanted to get a snapshot of this. Could stand to be taken at higher magnification.

Messier 15

Unguided, 212 x 15 sec JPEG frames, 1600 ASA, noise reduction enabled. This globular cluster and the stars around it bare a close resemblance to the view of M13 in Hercules.

My next telescope...

This hybrid Cassegrain design from Vixen is awesome. The VC200L uses a sixth order aspherical primary mirror and a convex secondary mirror, replacing the meniscus corrector plate with a triplet corrector lens near the end of the optical chain. Focusing is performed using a 2" Crayford focuser at the end of the optical chain, rather than moving the primary mirror and suffering mirror shifts during focus. The optical tube is baffled and the secondary is oversized. At f/9.5 it is somewhat faster than traditional Cassegrains.

For $1700, it is certainly more pricey than my $380 Newtonian. Yet, the step in optical precision is significant, and comparatively well-priced against competing and mainstream high-end designs.

Of all the optical systems I've researched, Vixen's VISAC design is the only one that addresses spherical aberration, coma aberration, and field curvature. Even chromatic aberration is far less than the exceptional (and more exceptionally expensive) flourite lens refractors. Considering that field curvature is eliminated, suggests better optical correction than even a Ritchey-Chretien...and new manufacturing methods for RC scopes are producing some much less expensive designs

From what I've read and observed from vendors and blogs, I think the VISAC design hasn't caught on simply due to technical arrogance in much of the user base and limited marketing visibility. It just isn't sexy enough and there simply are not any additional distractions or operational steps to get in your way. But, as of today, you can buy them from Orion Telescopes online!

Eliminating the corrector plate and complex mirror focusing mechanism clearly helps reduce the manufacturing costs. Baffling and Crayford mechanisms are cheap. So, the cost is likely rolled up into the improved mirror coatings and the corrector lens. A fair trade, I'd say.

All my deep sky photography relies on the reflectivity of my 6" primary mirror and oversized secondary without any loss in light transmission due to an intermediate lens configuration, though my reflectivity is somewhere in the mid 90% range (it's less than $400 bucks what do you expect). So in my view, the VC200L decrease in transmissivity by adding a triplet lens is offset by the 1.8" larger aperture and higher reflectivity from the superior Japanese mirror coatings.

Don't just take my word for it, read this article by Astronomy Technology Today. Note, the article is taken from Vixen's web site as access online requires subscriber login.
...now I just need to save my pennies.

Messier 34

Unguided, 208 x 15 sec JPEG frames, 1600 ASA, noise reduction enabled.

Messier 52

Unguided, 223 x 15 sec JPEG frames, 1600 ASA, noise reduction enabled. Nice clear and dark night. Open cluster in Cassiopeia, discovered by Charles Messier in 1774. Even caught a glimpse of the Bubble Nebula near the upper left.

Baader Coma Corrector and the Sculptor Galaxy

Unguided, 247 x 15 second JPEG frames, 1600 ASA, with noise reduction. The camera was also fitted with a Multi-Purpose Coma Corrector (MPCC) from Baader Planetarium, Germany.

The MPCC attaches to the T-ring right in front of the camera, and comprises what appears to be 2 lenses complete with 7 layer coatings to provide a completely flat field and eliminate coma from the fringes of the field of view.

Well, I've definitely observed an elimination of coma around the edges of the larger master photograph (all my images are cropped to scale to a widescreen display). But, any time a lens is introduced less light makes it through, and two or three elements (lenses) has some impact. You can see in the image that the diffraction lines are barely visible and the stars less point-like.

Another unexpected downside due to the proximity of the MPCC lens surface to the CMOS sensor, is the radiated energy from the active CMOS sensor electronics in the camera being reflected right back onto the sensor! Arrrgh, this adds more noise the point it interferes with getting a cleaner image. I've taken several other photos so far with and without the MPCC, and the additional reflected noise is consistent. Never occurred to me before I bought the thing.

Its my opinion at this point, dealing with coma means spending more for a higher quality instrument such as a Mak-Newt, SCT, or of course an RC telescope. There is a hybrid made by Vixen, the VC200L, where the front plate is removed and a 3 element corrector optic is placed at the end of the focuser assembly. Comparable light loss might be mitigated by the fact it has an 8" aperture rather than 6" in my scope. Its possible the VC200L lens surface is far enough from the camera's CMOS sensor (at least 3 or 4 inches) that it might reflect very little back.

Messier 39

This open star cluster is approximately 800 light years away and estimated to be from 200 to 300 million years old.

Unguided, 200 x 15 second JPEG frames, 1600 ASA, with noise reduction enabled.

Galaxy and Cluster, NGC 6946 and NGC 6939

An interesting view, here a nearby spiral galaxy, NGC 6946, highly obscured by interstellar matter of our own galaxy is contrasted in this photograph by a distant open cluster, NGC 6939, in the same field of view.

Since 1917, eight supernovae have been observed in NGC 6946.

Unguided, 204 x 15 second JPEG frames, 1600 ASA, with noise reduction enabled.

NGC 7293, Helix Nebula

Tried a difficult target, the Helix Nebula, a large planetary nebula. Given that it is one of the closest of such nebula to our solar system, you would think it was much more distant. Apparent brightness is spread across a vast surface relegating any other observing details deeper in the IR range. Clearly, photographing this kind of deep sky object approaches the limits of what can be reasonably done in an evening with the latest DSLR camera.

It is possible another alternative might work, taking successive exposures over several evenings. I have yet to try this. Maybe if I have time during Christmas break. Would really need to leave the telescope outside and in place for a whole week.

Unguided, 250 x 15 second JPEG frames, 1600 ASA, with noise reduction enabled.

Messier 27, Dumbbell Nebula

Yes, Dumbbell here was the first planetary nebula to be discovered, and resides in the faint northern constellation of Vulpecula. The central star is a white dwarf, larger than any known white dwarf. In 1970, astrophysicists found the nebula around the star was expanding at 31 km per second, suggesting an age of only 9,800 years!

Unguided, 202 x 15 second JPEG frames, roughly 51 minutes of exposure, 1600 ASA, noise reduction enabled. Just stacked and stretched, great natural color and contrast. The images were taken between the hours of 10:30pm and 1:00am in the morning. The prior blog entry regarding M33 was taken afterwards until about 3:30am in the morning. The M33 shot is much more grainy, given largely to being in the portion of the sky over the Tucson light dome. In the future, I should probably avoid imaging toward the West and Southwest portions of the night sky.

Messier 33, Triangulum Galaxy

Unguided, 203 x 15 second JPEG frames, roughly 51 minutes of exposure, 1600 ASA, with noise reduction enabled.

This was a fairly dim object, even though it is listed at about magnitude 7. Could stand to get twice as many exposures to bring out more detail. Still, a really spectacular face-on spiral galaxy. It has also been referred to as the Pinwheel Galaxy, even though Messier 101 is officially recorded with that name.

Messier 45, Pleiades

At last, another chance to try the Pleiades now that I have had much more practice. This image is comprised of 288 x 15 second JPEG frames, unguided, 1600 ASA, approximately 72 minutes of exposure! A personal record.

This cluster is number 45 on Charles Messier's list of nebulous objects. This beautiful cluster of stars was also mentioned by Homer around 750 B.C.. It has had many names, including Seven Sisters, Matariki (New Zealand), and Subaru (Japan). Comprised of hot blue stars formed over the last 100 million years, the brightest stars illuminate ancient dust collected from the original formation of stars giving it the bluish nebulosity.

IC 5146, Cocoon Nebula

Well, here's a tough one. Unguided, 180 x 15 second frames, 1600 ASA.

The Cocoon Nebula is an emission, reflection, and absorption nebula all woven together in a young developing star cluster. Formed only 100,000 years ago and is 4,000 ly from Earth, fairly close in astronomical terms. What makes this interesting is the dark nebula you can see (sort of) trailing off to the left of the picture.

The LCD "zoom/review" focus method

A simple way to focus your DSLR for astrophotography without a lot of other expense like a costly knife-edge device or laptop with cabling and focus control software, involves zooming in and reviewing diffraction lines from a bright star near the deep sky target. This method works best with a Newtonian telescope, where the secondary mirror is suspended by 3 or 4 straight flat bars 90 degrees apart within the optical tube assembly.

With diffraction lines, the zoom-review focus method can be accomplished very quickly. Three focus frames taken during the prior night's efforts are shown here.

The metal bars commonly referred to as "spider" vanes, cause the attractive (or distracting) star-like diffraction lines observed in my photos. I find it a pleasing photographic effect. For non-Newtonian scopes, one could fabricate some vanes to attach in front of a tube assembly to create diffraction lines just during focusing. I've seen some photos on other web sites where amateurs have used Photoshop to add the diffraction lines artificially (honestly, it looks as fake as it sounds).

You always want to try and focus on something nearby, as slewing the telescope clear across the sky can disrupt the mirror collimation on your touchy Newtonian.

NGC 869 and 884, the Double Cluster

Another break in the storms, maybe this is the end of it. Under a beautifully clear and dark night, I was able to capture the Double Cluster below. Unguided, 257 x 15 second JPEG frames (roughly 64 minutes of exposure), 1600 ASA.

I attempted to get a parting shot of M6 too as it moves closer to the horizon, but the glow off my wall from my neighbors flood lights really ruined it. Even with 186 frames captured, it was like trying to take a picture with the moon out. Argh.

Messier 7, Ptolemy Cluster

Unguided, 168 x 15 second JPEG frames, 1600 ASA

Messier 16, Eagle Nebula

Alright, this is much better. Unguided, 201 x 15 second JPEG frames, 1600 ASA. I've also included a before and after comparison with previous take to illustrate the difference more "signal" can make!

Messier 31, Andromeda Galaxy

Unguided, 201 x 15 second JPEG frames, 1600 ASA