Tuesday, December 18, 2012

No More Mills Fleet Farm

Let's keep this simple.
  • I want hunters to keep their hunting rifles.
  • I want homeowners to keep their handguns intended for self defense. Even if it means that statistically they are more likely to be involved in handgun accidents involving their own children. They have a right to weigh the risk/benefit involved for themselves.
I see no legitimate reason for anyone not in law enforcement or the military to possess, much less use tactical weapons (semi-automatic rifles, or any weapon that allows a large number of rounds to be fired without reloading). Count in that any sort of armor-piercing or rounds designed to maximize damage to a person's body (such as soft- or hollow-point bullets). No reason at all. Personal gratification is not a legitimate reason.

Guns and Mills Fleet Farm

I love MFF. For those of you not in the Midwest area of the USA, it's a giant general store of sorts. Lots of good things at great prices. Tools, yard supplies, sporting goods, automotive items. Helpful, friendly staff. I buy my deep cycle batteries there that I use to power my Astronomy gear. Yes, we've even bought a gun case there.

Unfortunately they also sell semi-automatic rifles, tactical rifles and magazines, which is their right under the current laws. And because of that MFF and I am parting ways. I'll be shopping elsewhere until they stop selling these things. Menards and other stores will do quite well at replacing MFF. I've written MFF about this; I don't anticpate a reply.

Guns and John Kline

John Kline is a Republican and the Congressional Representative of District 2 in Minnesota. He has an "A" rating from the NRA. I've never voted for him, and quite possibly never will. I'd like to think that he's a rational man, navigating the messy world of politics by the use of his own moral compass,  and not simply beholden to the NRA and the gun culture. He will probably soon have a chance to participate in discussions about how to move away from the violent use of guns in mass murders. Independents like me will be watching closely to see what he says and does about this problem.

If you're from District 2, write to him; tell him what you think. You have the power, through him, to salvage some shred of good from the evil visited upon the children and people of Sandy Hook.

Guns and Acts of Terror

I doubt the shooters in the many recent multiple homicides see themselves as terrorists, but that is exactly what they are. After the terror attack on 911 people were afraid fly, now they are afraid to send their children to school. At what point do we draw the line against this? Are we so engrossed in our own selfishness that we can't look out for our fellow citizens? Are we so weak that a group of people (the NRA, gun manufacturers, and gun merchants) can pervert the second amendment in the name of their own greed and threaten the safety of all of us?

Many Americans fear for their own lives and the lives of their loved ones because of the profusion of weapons no one legitimately needs. That the NRA supports the distribution of these weapons in our society makes them no better than terrorists.

I thought there was a war on terror. Please don't let the terrorists win.


Poor Fleet Farm! They get it from both sides. I came across a gun advocate forum that was ripping FF for not letting customers carry unconcealed guns through their stores. One person was upset because he couldn't carry his rifle into and through the store to the gun counter for service. The fact that if he had done that he might be taken as an armed robber didn't seem to register with him.

Thursday, November 8, 2012

On politics...

I'm going to momentarily step out of the role of amateur astronomer and comment on the election of a couple of days ago. In my state of Minnesota the Republicans got a severe thrashing, losing both houses of state government and seeing two amendments they promoted be denied. A very conservative house member was voted out after his first term, and the radical Michelle Bachmann barely won reelection to another term.

The Republican error--and a common one made by most of us these days--was inflating their own sense of moral and practical rightness. They gained control of the legislature only two years ago, selling themselves broadly as the party of jobs, and to a narrower constituency as the party of morality. The honeymoon was brief. Many of the new members were inexperienced at participating in government at a high level, and they quickly found themselves being outmaneuvered by the Democratic Governor. A sexual scandal erupted that became messy because of legal fees.
Failure to work with the Governor led to a shutdown of state government. The state Republican party outspent their resources and hardly looked like the party of fiscal responsibility. Republicans then dithered on a contentious stadium-building issue (managing to look both obstructionist and disorganized).

Republicans sealed their fate with two state constitutional amendments. The marriage = one man + one woman amendment was a slap at GLBT families, liberals, and libertarians, the latter being a significant portion of the Republican base. The voter ID amendment addressed a non problem and was perceived as oppressive and self-serving.

Republicans apparently judged themselves so popular and their mandate so large that they thought their base would carry them to any victory they sought. It worked out otherwise.

Democrats would do well to remember this lesson as they sweep back into power, lest they repeat mistakes they've made in the past. I consider myself an independent, and I hope that the Republicans can regroup around a more moderate base and continue to advance the ideals of conservatives.

Monday, October 29, 2012

HOASP, CCD Returns

It's back, and it works. SBIG contacted me after about three weeks that the problem had been diagnosed. The news was not good: both circuit boards were fried and would have to be replaced. The cost would be $695.


I told them to go ahead and do the repairs. My options were limited. The filter wheel and 36mm filters I use are tied to the ST-8300 and can't be easily adapted to another camera. While $700 could probably buy a used CCD, but it wouldn't be as good a camera as the 8300--and I would have to add the cost of a new filter wheel and filters to that.

A week later the 8300 came back, and it works like new so far as I can tell. The fan runs and the filter wheel aligns itself when powered up, the shutter clatters when initialized, and the cooling system cools. It's been cloudy here since the camera was returned, so all I've been able to do so far is shoot dark frames.

Two questions I asked SBIG that you may be interested in if you are an ST-8300 owner:

Q. How did the breakdown happen, and how can it be prevented in the future?

A. The camera apparently much prefers to be powered up first; always connect the 12V power before plugging the USB connection into your laptop.

Q. Even though the sensor was not replaced, do the new boards mean that I need to shoot new dark frames?

A. Probably not, but it would be a good idea to shoot some test dark frames that match the exposure time and temperature of old dark frames. If they compare well, then my flat library doesn't need to be rebuilt.

So I'm back in business, once the skies finally clear. While I'm waiting, I'm going to make myself a poor man's camera case using a Plano #761 toolbox, some foam from a craft store, a twin-blade electric carving knife and a hot glue gun. It won't be a Pelican, but it will cost about 1/4 as much. I'll post more about this micro-project when I'm finished.

The Heart of America Star Party was a viewing and imaging bust, but I had a good time, as did most of the attendees. All three nights were cloudy, and it rained pretty much from the second night through all of the third day, with a lot of lightning the second night. Severe weather was forecast for the third night so I folded my tent and stayed at the Days Inn in Butler. Fortunately the severe weather bypassed the observing area.

HOASP featured an abundance of knowledgeable and friendly people, excellent talks, great food (assembled if not made on the premises) and nightly movies to help people cope with the clouds. One vendor (Bushnell) was on site, the daily door prizes were decent (I won none). One word of advice: If you decide to play bingo, take several cards. It's a cutthroat game, bingo.

I'll definitely want to return.

Sunday, October 7, 2012

Waiting Time

One week since I sent in my CCD to SBIG, and one week to go to the Heart of America Star Party 2012. I didn't expect to hear anything from SBIG this week; my impression is that the repair queue is about two weeks long. After that--in a few short days--you hear from them, they do the repair, and it's on its way back to you. So I'm guessing that I'll get it back sometime around the last week of October.

On the HOASP front, there's good and bad news. A friend who also owns an ST-8300M has agreed to loan me his for the trip. CCD imaging is back on the menu. I'm still waffling about which scope to bring, the TV102 or C925. Today, I'm favoring the TV102. Stand by.

Bad news is the weather forecast. At this time it has all three days of HOASP as showers and thunderstorms, so the whole CCD issue may very well end up moot. I've picked three targets as if there will be three nights of clear sky. The helix nebula (NGC 7293), The sculptor galaxy (NGC 253), and The foxface nebula (NGC 1788, a reflection and dark nebulae in Orion) Will any get imaged? Or will I come home having collected only mildew?

Saturday, September 29, 2012

CCD Camera Goes in for Repairs

My ST-8300M began acting erratic at a star party a couple of weeks ago. I was able to pull a couple of dark frames off it when it lost contact with my laptop. Subsequent tries to reconnect all failed. Either the camera couldn't be found by the camera control software, or Windows was declaring it an unidentified USB device.

Cable swapping and driver reinstallation ensued to no good effect. It was time to consult a higher source.

I contacted SBIG and they suggested trying to use another computer. I loaded the drivers onto my desktop computer and got the same results. SBIG suggested sending in the camera for diagnosis and repair.

Two days ago I mailed it to them. I expect to hear back in a couple of weeks, and then perhaps another two weeks for repair and the return trip. Which means I'll miss the best part of autumn, and imaging from the Heart of America Star Party. Bummer.

The fallback is to rely on my DSLR for some dark-sky imaging at HOASP. I think it would be nice to do some reflection nebula imaging, perhaps the Iris?

Monday, August 27, 2012

Goodbye, Sky and Telescope

In an earlier entry I posted a graph showing the diminishing page count of Sky and Telescope magazine. It's still at 86 pages each month. And now it's renewal time for me.

Reasons to renew: Product reviews, articles on interesting topics, pretty picture, astronomy news, advertisements.

Reasons not to renew: The magazine has become a two-hour read. The astronomy news can largely be found elsewhere on the Internet. Ditto the pretty pictures and advertisements (which now tend to target high-end spenders). The hardware reviews are too brief and often are about products for which I have no interest. Article topics tend to repeat over time; not much new can be said about alignment of your telescope that hasn't already been written about it. The monthly sky guides are mainly for beginners; much of their function can be replaced by software. I seldom read the editorial articles or letters to the editor.

The only reason I can muster to renew that makes much sense is that I need to keep up on popular astronomy on behalf of the classes I teach, and S&T offers a convenient way to do that. So I've reupped for three years. I would have gone for the online-only version, which is cheaper, but I didn't care for the image quality of their online version. I'll keep looking in on it.

Monday, July 23, 2012

Another telescope, WOW, images

Yes, I've purchased another telescope, this time a used C9.25. This is something I've wanted for a long time; it fills the niches for long focal length deep sky imaging and planetary imaging/observing. I've been using it so far only for deep sky imaging, and it's very nice, even at f/10. Here are some samples:

Messier 16 (Eagle Nebula) LRGB

M27 (first light image) Ha+OIII full frame
NGC 6820 (full frame) Ha
Sort of looks like M 16, doesn't it?
NGC 6781 (full frame) Ha + OIII
At f/10 it has a nice flat field. These are imaged with an SBIG ST-8300M and Baader filters. I usually bin 3x3.

WOW stands for the Wisconsin Observers Weekend, an annual event that brings together amateurs from all over Wisconsin and nearby states. It's held at the lovely Hartman Creek state park near Waupaca, WI, and features very dark skies. If you're in the MN, IA, WI, IL area and looking for a nice group of people to observe with under great skies, you can't do much better. I had bad luck with a faulty dew preventer, but still managed one night of imaging that got me the M 16 image above.

Next for me is the backyard observatory, the resumption of the school year, and a weekend trip to Jeffers Petroglyphs. More images coming soon, too.

Monday, June 25, 2012

MK-67 morphs to C9.25

One of the local club members put his C9.25 up for sale a while ago. I've always wanted a C9.25 because of its reputation and how it fit my "long-term imaging plan." It's got a nice aperture and versatility, being either a nice long f/10 or a reasonably fast f/6.3. I would just have bought it but for the fact that it would make my MK-67 redundant.

The solution was to sell the MK-67 and use the funds to help buy the C9.25. Two nights ago I did the former, and last night the latter. Tonight I've got it out on my CGEM to see If I can do an imaging dry run at f/10. The target will be good old M 27 in H alpha.

I wonder how often sales act like dominos. The selling of my MK67 triggers the C9.25 sale, which has its seller looking to buy a used Fastar system for his C11. It's too far downstream to ever know if the Fastar seller will turn around and buy something else, but I wouldn't be surprised if  that happened.

First visual check: Alignment looks perfect. Views are beautiful! Saturn sharp and contrasty (if that's a word); moons like pinpoints. Spica dazzles with no false color. Next up, getting the CCD started up as soon as it's dark.

Friday, May 25, 2012

Canon Lens on SBIG, ImagesPlus upgrade

Last week my Canon lens-to-SBIG ST8300M adapter arrived. Beautifully machined, it is. Expensive, it is! I tried it out with my 50mm f/1.8 and 17-70mm f 2.8-f4.5 zoom lenses. Images showed nice stars at the center of the fields, but progressive defocus toward the edges. I should not have expected anything different, since I had the lenses wide open.

How does one stop down a fully automatic Canon lens? Turns out it's easy, just follow these instructions. They work for me. My thanks to Haje Jan Kamps for posting them at pixiq!

Now if it would clear up for one night I could test the improvement.

I also upgraded to ImagesPlus 4.5, but am having a little trouble getting my old serial number to complete the registration. The always-helpful Mike Unsold, creator of IP, is on the case, so I should be up and running soon.

Monday, April 30, 2012

Observing Stars and Planets during the daytime

You may be surprised at how many planets and stars you can see during the daytime! You don't need a big or specialized telescope, Although it's particularly easy if your mount has go-to capability. But there are a few things to keep in mind if you want to do this safely.
  • NEVER look at or near the sun unless you are using an appropriate and correctly-fitted filter on the telescope objective. If you're not 100% sure about what you're doing, stick to observing at night.
  • CAP the telescope objective whenever slewing near the Sun; if the scope slews across the sun, heat may damage your telescope. Make sure your cover is secure and won't fall or blow off.
  • ALWAYS keep your finder telescope's objective covered, and cover its eyepiece, too, just to be extra safe. You won't be using your finder anyway. Even safer is to remove it from your telescope.
  • DON'T do slow search slews near the sun while looking through the eyepiece. If even a small portion of the Sun's disk slides through the field of view for a tiny moment eye damage would result!
If you get the feeling from all this that it's not particularly safe to look near the sun, GOOD.

Now, assuming you're not completely scared out of trying this, here's how to spot daytime stars.

If possible, the night before do a good polar alignment followed by a multi-star alignment so that its go-to is ready. Some mounts let you retain the go-to information with a Hibernate mode. If your mount has that feature, use it.  The next day, awaken your mount from Hibernation.

Use the go-to to find the brightest object other than the Sun. This may be Venus or the Moon; both are easy to see during the daytime when far enough in angle from the Sun. "Sync" your mount to the object if possible. Syncing is useful for doing go-tos to targets near the synced object. For example if you have synced to Venus in Taurus, you might select Rigel, Capella, or Betelgeuse to look at.

Once you've gone to the target star, you may have to hunt a bit. Use a low-power eyepiece and scan outward from the center of the field of view. I use a slow spiral when searching. Don't bother using averted vision, as it's ineffective with the daytime brightness. Remember that you're looking for a tiny sparkle of light, not a glaring bright star.

Your luck will be best when you look farthest from the Sun, when the Sun is low in the sky, and when your target star is well above the horizon. The larger your telescope's objective, the dimmer the stars you'll be able to see. Even with a small telescope there's a lot you can see. If the sky is hazy or there's a thin layer of clouds, you will probably be limited to only the brightest sky objects.

Here's one days observations I made using a 72 mm ED refractor on a CGEM mount. Most of the time I was using a 12.5 mm or 9 mm eyepiece, giving magnifications of  about 35X and 48X. I tried a variety of color filters, but only a yellow #15 seemed to help.

Planets I observed:
  1. Venus was my starting point and on this day was a brilliant crescent.
  2. Jupiter (-2.00) was a ghostly disk
  3. Mars (-0.3): Much easier than Jupiter at -2.00, a distinctly red disk.
I tried Mercury, but the the sky was too bright.

Stars I observed (and their magnitudes):
  1. Capella (0.08) was easily seen
  2. Betelgeuse (0.45) was easy when it had risen high enough, and showed distinct color
  3. Aldebaran (0.87), fairly easy and had a distinct reddish tint
  4. Procyon (0.4) not too bad
  5. Pollux (1.16) easy
  6. Castor (2.0 and 2.9) This double was split cleanly with a 6mm (72X) eyepiece and #15 yellow filter. The reason I could see the faint companion was that I knew exactly where to look, which makes a tremendous difference.
  7. Alhena (1.93) no problem
  8. Sirius (-1.44) Quite easy despite being low in the sky.
  9. Rigel (0.18) fairly easy.
  10. The three belt stars of Orion, from east to west (Alnitak, 1.74; Alnilam, 1.69; Mintaka, 2.25) only Mintaka was moderately difficult
  11. Saiph (2.07), the SE foot of Orion. Easy
  12. Bellatrix (1.64), the NW shoulder of Orion. Also easy. With Betelgeuse, Saiph, and the belt stars, it's easy to see all the the "signature stars" of Orion during the daytime!
  13. Regulus (1.36) easy
  14. Algieba (2.01) fairly easy
  15. Dubhe (1.81) Very clear.
  16. Merak (2.34): Yes.
Not bad for a late morning and mid-afternoon's work. Unfortunately, clouds rolled in and I didn't get to do more during the late afternoon when more stars would have certainly been visible.
This shows how you can see stars down to almost 3rd magnitude during the daytime with a small telescope. If your telescope is larger, you can probably do better than I did.

Try this out for yourself and let me know how you did. You might be surprised at how pretty stars are during the daytime!

Friday, April 20, 2012

Stupid Imaging Trick #2

I'm impatient. When it comes to imaging, I want as much time with the shutter open that I can get. My setup, currently a cement pier, allows me to polar align my mount one night and leave it in place so long as good weather holds. Normally I polar align and also do a two-star alignment as well. When I'm done I return the mount to its "home" position and power it down.

The trick comes into play when I start up the next night. Instead of repeating the two-star alignment, I simply go to the alignment star nearest to my imaging target. For example, the last week that has meant Mizar, which a short distance from M101. Normally Mizar shows up somewhere in the finder scope's field of view. I then sync the mount to it with a little slewing. Then using go-to I move to M101, and it's right in the center of my CCD's field of view.

This doesn't produce a huge time saving, but syncing is faster than slewing to several stars. Every saved minute is a minute sooner you're able to pack up and go to bed!

Tuesday, April 17, 2012

M101 Progress

This Friday I may be able to complete the acquisition part of my M101 project. At the present time I have 13 hours of H-alpha, two hours of luminance, 40 minutes of red and 40 minutes of blue. (Both the R and B are binned 2x2 on board my ST-8300. I feel that I need to add at least 20 minutes of red, 20 minutes of blue, and an hour of green before I'm ready to process it all. I have the dark frames ready to go.

Friday night is a gathering of imagers out at Onan Observatory, and the forecast is for clear skies. There should be a good four hours of imaging time between the start of darkness and RA end-of-travel. Deduct from that the time for polar alignment, (re)focusing, and the usual snags and glitches.

The last several years my clear-sky luck at Onan has been terrible. I won't be surprised if the clear forecast busts.

Thursday, April 12, 2012

Stupid Imaging Trick #1

So lately I've been imaging with my camera cooled to -25C. Last night I shot several hours of light frames, but alas, I have no matching dark frames. Tonight I thought to do it after dark, but it's too warm, the camera can't get down that far. What to do?

I put the camera in our chest freezer that runs at about -18C so that the USB and power cable trailed out to my laptop. I set the camera's temperature to -25C, and it's now collecting the needed dark frames. All need to do is remember to seal the camera in a zip-loc bag when I remove it from the freezer, so that condensation won't build up in and on it.

Kind of dumb, but I'm sure I'll come up with others.

Focusing; imaging at a dark site

I recently posted that I was going to test the parfocality (if that's a word) of my Baader LRGB and narrowband Ha/SII/OIII filters. The test has been done, and it was less than conclusive. If you use a Bahtinov mask to do focusing, all the filters are essentially parfocal. That is after focusing for one filter, they're all in focus. They all have nicely centered spikes in the test images.

However, the centered appearance of the central spike when estimated by eye is only approximate, and the range of error is about the same as the range over which final focusing is done. I think you're still better off handling focus with the assistance of software that quantifies the sharpness of focus. Likewise, I think every time you change filters, it's time to refocus. At least that's what I'm going to do for the foreseeable future.

Last night I gathered another bunch of photons for my M101 project, this time from the dark-sky site of Cherry Grove. It's really nice to have a dark place to image from only an hour's drive away. The site has a warming house, too, which was nice. Imaging was largely automatice, so I could while away the hours reading and listening to the Twins game in comfort, as the temperature outside fell to around 0C.

Added note, 5/22/12: Further imaging with the Baader filters suggests that the LRGB filters are essentially parfocal when used with an apochromat. Likewise the Ha-SII-OIII filters.

Saturday, April 7, 2012

Parfocal test of Baader narrowband filters


There aren't many nebulae in my sky right now, and the full moon means there's no point in traveling to a dark sky site to work on my M101 project. So tonight I'm going to investigate how parfocal my Baader Ha/SII/OIII and LRGB filter sets are. I don't expect the two sets to be parfocal with each other.

It's a simple plan at this point. I'll use 20 second exposures of bright stars taken through a Bahtinov filter. The stars are chosen to span the spectral range from blue to red: Altinak (spectral type O), Sirius (A) and Betelgeuse (M). Best focus of Ha will be the starting point, and then I'll cycle through the other filters and shoot another Ha to catch any focus drift.

Once the narrowbands have been tested, I'll repeat shorter exposures with the LRGB, initially focusing the L filter.

After that I may move on to shooting more long-exposure images in Ha of M101.

Thursday, March 22, 2012

Celestron Alignment Stars Diagram

Celestron uses the 80 brightest stars for the stars that can be used duing alignment. This is a subset of the named stars list. While I may know many of the stars, I certainly don't know them all, so I've prepared a GIF image file marking the constellations and the locations of the 80 stars. If you find it useful, here it is:

The alignment stars are in bold letters. Here are links to the full-sized variations of the chart:

Black stars on white background
White stars on black background
Red stars on black background

Credit: The background constellaton chart (a PDF file) comes from this U.S. Naval Observatory page.

Tuesday, March 20, 2012

Guide for drift polar alignment

After giving up trying to memorize how to do drift polar alignment I wrote a quick-and-dirty guide for doing it and posted it on my home page. You can find it here. Please report any errors in it you find so  that I can correct them!

Monday, March 12, 2012

Seagull Nebula and Gum 1

Imaging on four hour's sleep is a bad idea.

Take the other night, for example. My targets were the Seagull nebula and Gum 1 (the bird's head). My CGEM misbehaved (probably my fault), I forgot to switch to unbinned after focusing, my makeshift AT72ED mount adapter flexed in the wind. My target and guide star spent almost an hour behind a tree. I shot my dark and bias frames unbinned and had to reshoot them the next day. But it was clear and warm.

Seagull nebula
It's not that good, but it's an image. Details: AT72ED (420 mm FL), ST-8300M at -20C with H alpha narrowband filter. 8 x 10 minutes. 3x3 on-camera binned. ImagesPlus and Photoshop.

I have to get AT72 piggy backed on my guide scope, or do something about firming it up. And I need more sleep.

Monday, February 27, 2012

Wide-Field Imaging with EOS Lenses

I would like to do some very wide field imaging, in which I can capture entire constellations or significant parts of them. This means imaging with focal lengths less than 200 mm, which can be done with camera lenses. I have a few Canon EOS lenses, and lenses that can be adapted to work as if an EOS lens, but the problem is mating the lenses to my SBIG CCD.

A search of internet forums suggests that there's only one way to do this: With an SBIG EOS to ST-8300 adapter ring. The problem is that this adapter is pricey: $295 + shipping. A Wanted ad on Cloudy Nights failed to produce someone willing to sell a used one, so yesterday I faced reality and ordered one from Oceanside. I should say, back-ordered it. With luck it will be here for the warmer weather expected to arrive in April.

Update 2/27: OPT wrote that the adapter would be delivered no earlier than late April! Tomorrow I'll call around to see if any other dealers have it in stock.

Update 2/28: Oh, well. It seems that SBIG items are usually special order most places and are fulfilled in 30 to 60 days. I'll stick with OPT.

Thursday, February 23, 2012

Alternative views of M31 and M104

I created the following images while doing class prep for my astro class and thought they might be of interest. I wanted to show how M31 would look from a view above one of its poles, so I tried to compensate for the foreshortening we see because of its inclination to us. The goal was to show the central bar more clearly for those who have trouble seeing it.
M31: Visible light (left) and Infrared (right, Spitzer NASA/JPL/CalTech)

the left image is one of mine, and the second is a Spitzer image from NASA/JPL and CalTech. My image of M31 is not so hot; if you want to try this yourself, you would do better to start with this amazing image. I think I've got the two images reasonably aligned and scaled to match. The brightest portions of the Spitzer image coincide with the dark dust lanes in the visible-light image.

You might find this fun to do with other inclined galaxies. It won't work with very nearly edge-on galaxies. Here's the Sombrero, for example:
M104 (Sombrero Galaxy, NASA Hubble)

Notice how the central bulge obscures the more distant portion of the dust/gas ring.

To remove foreshortening first rotate an image so that the long axis of the galaxy is either horizontal or vertical. Then resize the image, stretching it greater in the direction of its thinnest axis. (Make sure to turn off your graphics program's preservation of the aspect ratio.) Adjust the stretch amount until you have the galaxy looking round and you're done. We assume the galaxy is round, but that's not always the case. It's a decent first guess.

Thursday, February 16, 2012

PEC at last, maybe.

Finally a clear night, maybe. And the end of my head cold, maybe. And an understanding of how to use PEC, maybe. Results to be posted here, maybe.

The results: PEC seemed to work fine, although I have no way at present to objectively confirm that. My setup (AT72ED and autoguiding ST80 side-by-side on the mount) was far out of balance, and I had to up the PHD signal length to 1000 ms. That allowed PHD to correct for the problem, but the results were less than desirable. My target was M44--high cirrus precluded looking at nebular targets--and it was more an exercise in LRGB imaging and processing. Here's the result:

Messier 44

This is a fairly unimpressive cluster, with quite a few blue stars. Normally I don't like diffraction spikes, but they might add some visual interest to the image. (L=20x3min, R=10x3min, G=5x3min, B=10x3min). I spent a lot of time trying to get the color right. I'll probably redo this using the color balance workflow suggested by Ron Wodaski.

Just to give you an idea of what the PEC was trying to deal with, here is the PE for my CGEM:

8-minute cycle of PE, average of 10 runs
That's about 18 arcseconds peak-to-peak.

I've now jury-rigged a couple of dovetails together to get my setup balance, so next time I'll see if I can get things tracking better. Next time promises to be some time off as the weather has moved into a period of instability. *sigh*

Saturday, February 11, 2012

A Cautionary Tale

Wellll, it's been both head cold and weather cold time for me. Clear and cold nights have coincided with my lingering head cold, so I have no news to report.

The Tale? Earlier today I spotted a for-sale ad on Cloudy nights from the person who sold me my used AT72ED. He sold that scope because he wanted to move to something larger, an AT111EDT. He bought the AT111 and sold his AT72 thinking he no longer needed it, and that the smaller scope would help pay for the bigger scope. Sensible plan, really; how many scopes can a person use at one time?

The AT111 weighs 11.2 pounds compared to the AT72's 5 pounds, and perhaps more important is larger and a little more difficult to handle. I know my TV-102 surprised me at how large it was and how careful I had to be when moving it around. Not the the 102 is fragile, but I think that refractors in general are deceptively small in appearance.Once you start carting them around you find out otherwise. Just ask anyone who owns a 6-inch refractor--it doesn't have the same portability as a 6-inch Dob!

Sadly, the AT72 seller developed back problems that needed surgery to correct, and his new AT111 is now too much for him to handle. He's put it up for sale. It's unknown if the larger scope caused his back problems. I sort of doubt it, as back problems can reassert themselves for no clear reason at all.

The caution to this tale? It's tempting to suggest that one should never sell one's telescope, but that's utterly illogical and makes little economic sense. And besides, if everyone did that, where would I get my telescopes? 

I think the lesson here, if there is one, is that a factor in deciding when to sell a telescope should be the "niche" it fills in your hobby. The AT111 and AT72 are different enough that they can serve different purposes; the former is a serious scope good for almost any purpose, while the latter is a great grab-and-go scope.

Sorry for this. I know it's not as if you wanted another reason to anticipate "seller's remorse." But it can and does happen.

Tuesday, February 7, 2012


I've been under the weather a couple of ways lately. It's been very cloudy and I've got a headcold. Having the little viral critters inside me made me think about the kind of critters that share the outside world with me.

I live on the upper portion of the Minnesota River valley, a wide expanse with gentle slopes and a broad flood plain. The area has been settled for almost 50 years and the woodlands have long ago been lost to agriculture and urban development. We've seen deer only twice in our back yard in almost 30 years. One time we saw a very bedragled fox. Other than that it's mostly bats, rabbits, woodchucks, raccoons, squirrels and mice. Pretty tame, all in all. The really big mammals like bear and moose stay well north of here.

I've never seen any mammal larger than a rabbit or stray cat while observing. I've no desire to see a raccoon (or even hear one!) and the coyotes that are starting to return to the area have yet to show up.

Insect life has also been relatively benign. It's a draw between June bugs and mosquitoes for the worst of the lot. The folks who handle mosquito control do a good job here. June bugs are harmless but clumsy flyers that tend to scare me when they blindly crash into me.

I know that in other parts of the country you have to contend with nasty critters like spiders and snakes, but there's really none of that around here.

There are Owls, though. One night one swooped over me on the way to a tree it frequents. It was a huge Great Horned Owl, amazingly impressive as it flew past me. That it was perfectly silent as it did so was almost eerie.

Sunday, January 29, 2012

Clouds = Time to Plan

It's been cloudy, and that means time for making plans.  I now have my cables in order for doing upgrades to my mounts. It took a few tries, but I now have my CG5-ASGT updated. It can now do all-star polar alignments just like my CGEM. I really like this way of doing polar alignments. It's fast, reasonable accurate, and simple to do.

Next up is the CGEM. I'm going to look at its tracking. The last night it was producing "V"s, a back and forth motion in RA coupled with a motion in DEC (which may  be a drift caused by polar misalignment). I've got to make a "before" chart of mount periodic error, then run PHD and PECTOOL to see what they can do to correct this. It will probably take a couple of clear nights, so no imaging in the immediate future.

Tuesday, January 24, 2012

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.

Wednesday, January 18, 2012

The 10-Year Rule

Simply put, it is: "If you haven't used something even once in the last ten years, you should get rid of it." These are not easy words to live up to, particularly for someone like myself who has pack rat in his blood. But at least today I took a stab at it.

Gone are some Maxxum lenses from my Father's old Minolta SLR That hadn't been used since 1999. Also gone is the body of my Ancient Olympus OM1N SLR. This was probably last used in the mid 90s. I also have some Olympus-compatible lenses that I was going to sell, But I didn't, since they eventually prove useful.

The folks out at National Camera Exchange in Golden Valley were helpful in taking these items off my hands. I know I might have gotten more by selling the items someplace like EBay, but it seemed like too much hassle to do that. A week or so before I had taken the lenses to the MAS swap meet, but they generated no interest

It turns out that Olympus-compatible lenses can be fitted with an adapter enabling them to be used as Canon EOS lenses. No autofocusing or aperture control, but those are not important for astrophotography. So now I've got a bunch of lenses for using with my ST-83000M: 50mm f/1.8 Olympus; 50mm f/1.8 Canon; 17-70mm Sigma for Canon zoom; 135mm f/2.5 Tamron for Olympus; 400mm TeleAstranar f/6.3 (of dubious quality); 2X Vivitar Teleconverter for Olympus.

Before any of those can be mated to the ST-8300M, I need to get this. Hence the coupon clipping mentioned in an earlier blog entry. (The fund now stands at a about $110.) I'm particularly eager to try out the 17-70mm zoom and 135mm fixed focal length lenses.

Tuesday, January 17, 2012

Cold Weather Performance

Tonight I'm shooting O-III frames of the NGC 2244 (the Rosette Nebula) to add to those already taken the other night. Tonight will probably be the coldest night we've had so far this winter, which is not really saying much.  The next couple of nights we will probably go below zero for the first time this winter.  It's hard to believe this is Minnesota! Oh, and there's just a trace of snow on the ground. Really strange.

How well does everything run at 9° F (-13° C, the current temperature on our screened porch)?

  • Gateway Laptop
  • ST-8300M (which I'm running at -30° C just to match existing dark frames
  • Extension cord from house (it's one of those low temperature cords, highly recommended. (Note added: at 5° F the cord began to stiffen a little, but it was still easy to coil for storage.)
  • AT72ED, focuser remains smooth (Note added: at 5° F the focuser became rather resistant to change, as if the lubricant were solidifying or parts were tightening because of differential contraction.)
Less than perfectly, but passable:
  • Me
  • Cables (all are very stiff)

Not very well:
  • SBIG filter wheel.  (reports an error when moving from filter to filter, but gets there okay. I've noticed that temperatures in the teens or lower cause this behavior. Maybe these are built for the weather in Santa Barbara?)
  • CGEM mount. It looks like the mount is moving in fits and starts, elongating the stars in right ascension. I can't yet tell if this is periodic motion that can eventually be eradicated. It might well be something else, perhaps caused by the stiffening of lubricant? I tried to change the balance in RA, but that didn't help. Most of my images from the evening have very elongated stars. Maybe I can compensate by using the Ha image as luminosity and red, the OIII as blue and the SII as green?  Time to experiment!
It's perfectly clear tonight, with just the lightest breeze; by the end of imaging at midnight, the temperature had fallen to 5° F (-15° C). The poor CGEM simply couldn't track correctly in RA with the temperature in the single digits F. I'll have to look into this, as winter evenings around here are typically near that range.

Monday, January 16, 2012

Yet Another Accessory; Prelude to PEC

Like most go-to mounts, my CGEM can have its software upgraded. The CGEM also has the ability to compensate for periodic error in its tracking motion. Both of these require that the mount's hand control be connected to a computer. And there's the catch.

For some reason, Celestron refuses to create a cable that goes from hand control to a USB port on a computer. It continues to use a cable that requires the computer to have a serial port. Almost no laptops manufactured now have serial ports. Serial ports disappeared years ago, not long after parallel ports passed into oblivion. So why does Celestron continue to require them? Apparently so that they can overcharge for their branded serial to USB cable, which runs from $39 to $45, depending on the vendor. It's vaguely like what how many big-box stores charge for $60 HDMI cables that can easily be found elsewhere for $3.

In fairness, Celestron does include the hand control to serial port cable with the mount. So there's no need to purchase that half of the link.

Getting serial to USB is up to you. So far as I know any serial to USB cable will work; there's nothing magical about Celestron's model. So it's off to Amazon.com for a  cable that costs only about $11.

Saturday, January 14, 2012

Clip and Save

I'll admit to being a very frugal person. I have very few hobbies, and the only one on which I've spent an appreciable amount of money is Astronomy. Which you probably could already guess.

Back somewhere around 2003 I went to a local star party hosted by the MNAA. If you know the MNAA, "star party" is probably too formal a phrase for their get-togethers. I took along my Orion XT-10 Dob. One of the MNAA members let me try his Tele-Vue 31mm Type 5 Nagler with an OIII filter. At that point I had neither. If you know your eyepieces, you know that around then the 31 was one of the most expensive eyepieces around, and possibly one of  the heaviest. When I used it to look at the Veil Nebula, I was blown away. He and I decided that the 31 was made for the XT-10. Actually, given that back then they were both around $640, perhaps the XT-10 was made for the 31.

The hook had been set, and I realized the value of the 31.  There was no going back to my relatively inexpensive eyepieces, the best of which was a Panoptic 19. The 19 was a darn good eyepiece, but the 31 was something special. I had to have one.

But—how to pay for it? The Sunday advertisements gave the answer: By clipping grocery coupons. I held to a rule that I would only use coupons for things we normally used, not junk or extravagances. And several years later, I had saved up all the money I needed to buy the 31.  In fact, I kept clipping until I had enough for the OIII filter, too.

But wait, there's more to the story.  The person who hooked me on the 31 had sold his TV-102 a couple of years earlier to someone I knew from the annual star party at the Jeffers Petroglyphs. I had seen the 102 at that star party and greatly admired the views it provided. I became the 102's third owner in 2004. And yes, it works with the 31 as if the two were made for each other.

So why do I bring this up now? I've started clipping again, saving for a Canon EOS lens-to-ST-8300M adapter (about $300!).

Friday, January 13, 2012

One More Reason to Like the Internet

During the Summer of '10 I managed to break my CGEM mount when a Celestron power supply went wacko and fed it a voltage that was too high. While trying to pin down the problem I also hooked my CG5-GT to the bad supply. That mount also died. The little red LED didn't light, the hand control stayed dark.


The CGEM was new and still in warrantee, so Celestron fixed it. It has worked beautifully since returned, and I highly recommend the mount to anyone seeking something that can gracefully carry up to 30 pounds of gear. The CG5 languished, however, since it was not needed. Frankly, I admit I was not in a hurry to get it open and find that it was dead; which would mean that its resale value had probably fallen from $400 to $100. Not to mention that it was relatively useless.

I wanted this mount back in working order either to sell it or to use it at star parties as a platform for wide-field DSLR imaging of constellations.

Today I decided to open up the seemingly deceased patient, hoping that inside lurked a fuse or some component that could be replaced easily. No such luck; I found that the CG5's brains are on two small circuit boards devoid of fuses. Nothing seemed to be out of normal in appearance, so it looked like a case of blown electronics.

A google search ("repair CG5") turned up a 3rd party repair service that had gone out of business last December. There were also threads that reported dead mounts because of loss of contact in the center pin of the power socket. I dutifully widened the split center prong but nothing changed.

Another commonly reported problem was the failure of the on/off switch, which was said to go bad often in CG5s. Cleaning or bypassing the switch was said to sometimes restore function. I took out a jumper cable and easily bypassed the switch, hooked up the power supply, and the mount lived! The handset fired up, ready to do an alignment.

I popped the top off the switch and inspected it.  The contacts were a little dirty; there was the slightest hint of arcing damage by on the business end of the tiny, see-saw like strip of metal in the switch. I scraped it all clean, put it back together and the switch now works.

All thanks go to the Internet, and the people who shared their solution for a specific problem. They saved my mount!

Wednesday, January 11, 2012

Recent Imaging

I've been imaging over the past few days. The horsehead image from the last post did get its green and blue parts taken:

Flame and Horsehead nebulae
The Moon was Gibbous and nearby; some of its light snuck in and caused the blue-green flare at lower right. This has since been solved by extending the dew shield with some craft foam.

I also had a couple of clear nights during which to image the Rosette nebula. I collectd H-alpha the first night, but it was partly cloudy the second night and I didn't get very many OIII frames.  Consider this a preliminary composite image:

Rosette Nebular (NGC 2244)

The Moon was even brighter and closer to the target than for the previous image, but the dew shield extender worked fine. Next chance I get I will collect more OIII data, and for the first time try to get some SII as well.  I'll get a Hubble Palette image yet!

Wednesday, January 4, 2012

AT72ED First Light!

Tonight is the first imaging night for the AT72ED (at least for me with this telescope). My target is the area around the horsehead and flame nebula in Orion. A preliminary look at the images is encouraging. I think I may need to adjust the distance between the flattener and the CCD a little. It was H-alpha tonight of course.

The evening has had waves of altocumulus and altostratus move through, so it was fortunate I didn't set up the autoguider. It would have lost its lock several times. Speaking of lost, I wonder how many light frames will have to be rejected because of the clouds.

If tomorrow or Thursday night is clear I'll try a broadband blue filter (perhaps in combination with an Orion astrophotography filter) to pick up the reflection nebulae in the field of view.

Crazy weather for this time of year; the temperature was in the mid 20s with a very light breeze.

Added note: a couple of images taken using the AT72ED are included in the next blog entry.

Monday, January 2, 2012

Buying a first telescope

I have started or resumed this hobby four times, so in a way I have had four "starter" telescopes.

The first one was when I was a child, about ten years old. It was a Gilbert 2.5" Newtonian--which explains the sig line I use in my astro club's forum. Shoddy mount, shoddy tripod, shoddy finder, shoddy eyepiece, shoddy focuser, etc. In all ways it was inferior, but I loved it; I was a patient little kid, and was willing to fight that telescope for every view I could wrestle from it. For the astronomy-interested child with the right temperment, any telescope is like a piece of heaven on earth. Even the much-maligned department store scopes will serve. But I would advise buying something better.

Teenager: 6" f/8 Edmund Newtonian on a GEM. Darned good scope.

Graduate Student: 8" f/6 Meade Newtonian on a GEM. Also a darned good scope.

Adult (at least chronologically): ST80 Refractor on a GEM. Then a 6" f/12 Mak-Cass followed by a 10" Dob, then a 4" apo, and last a 72mm ED.

Lesson: Don't sweat the decision on the first telescope too much, as you will soon decide it is not completely adequate for your needs. It's good to start with a general purpose scope. Using it you will learn about telescopes, and about yourself: What you like to see, What you're willing to put up with, What you want in terms of bells and whistles. Then when it's time you'll better know what you want in The Next Scope.

My 6 and 8" Newts were close to being perfect general purpose scopes. Both had 48" focal lengths, which made them useful for planetary observing without having to resort to really short focal length eyepieces. They were at what seems like a nice balance point between fast and slow, so faint fuzzies were OK in them. Which one to get depends on the subjective factor of portability. The 6" was much lighter than the 8".

All that said, I agree with the advice of a 6" or 8" Dob. If you're thinking you really like looking at solar system objects go with a GEM that has a drive for right ascension. If instead your heart beats faster thinking of the faint fuzzies, get yourself an erect-image finder. That really helps with star hopping.

Speaking of star hopping, I'm old school. I think that Go-To drives are are appropriate in many situations, but not on a first telescope.

Telescopes are tools you can use to extend your senses to a cosmic scale. When you learn how to use your telescope and get to know how it reacts--what it can do and how you can get the most out of it and yourself--you become a craftsperson versed in its use. That's when the connection between you and the cosmos becomes direct in a special way. This will sound a little metaphysical, but I think that's when the telescope becomes a part of you and no longer is an artificial interface between you and the sky. The joy of that sensation is one of the reasons I love astronomy.

Sunday, January 1, 2012

Planning for the new year

It's a new year, and that puts me in the mind to start thinking about star parties to attend. There aren't many firm dates for these yet, so right now I have to guess a little on when they'll be. Let's look at the dates we know and use the new moons for guidance:




July 15-20: Nebraska Star Party.

July 19-22: Wisconsin Observer's Weekend (WOW). This looks promising, and is much close than the Nebraska Star Party

The August new moon is around the date of the weekend that items are submitted to the Minnesota State Fair.

South Dakota Star Party/Northwoods Starfest. Dates unknown.

North Dakota Badlands Star Party, in Teddy Roosevelt National Park North Unit. Dates unknown.


Iowa Star Party. This is usually around labor day, but this year the Moon is full on August 31. Probably they will have to push it to September 6 through 9. Augsburg College (where I teach) doesn't have the schedule out for Fall of 2012 yet, so it's about a 50% chance I can make it.

Jeffers Petroglyphs star party (once promoted as the Prairie Grass Stargaze). This is probably going to be in around the time of new moon in September, the 13th to 16th. I will be able to attend only Friday and Saturday nights at most, possibly only Saturday night. Bummer.


October 10-14: Heart of America Star Party, October 10-14. Day Classes make it impossible to attend.

So the year does not look very good at all. I'll probably go to the WOW, and make trips to Onan and Cherry Grove.