First Light Image for Gary Honis Modded Canon T2i

Two weeks after getting my camera back from Gary Honis the clouds parted, the moon was out of the sky, and my schedule permitted me to try it out. Finally!

As a target I chose The North American nebula, something I'd imaged before with my ST-8300 in LRGB. The imaging site had light green sky brightness, not nearly as dark as for the CCD image. The telescopes were nearly the same, an AT72 at f/6 vs. my current AT65EDQ at f/6.5. Total exposures were 81 vs 100 m so it's almost a dead heat in terms of expected brightness. Because of the high humidity and the lack of a window heater the CCD was cooled only to about 0C.

Here's the T2i image:

NGC 7000 with Canon T2i and AT65EDQ at Cherry Grove 2015

and here's the ST-8300M image:

NGC 7000 with SBIG ST-8300M and AT72 at Iowa Star Party 2013

The difference is mainly one of brightness and contrast, which is almost certainly a result of my processing. I think the CCD image is a little washed out. I like most aspects of the DSLR image except for the vertical bands that are most apparent on the right portion of the image. These appear to come from the dark frames (I shot only six) and my inexperience processing DSLR images.

Related to those bands, one big change I'm going to make this year is learning how to dither. Based on what I've read it's helpful to let the camera cool after the image is read, and that "lost time" is perfect for dithering.

For this image I powered the camera using the Neewer AC power adapter and controlled the acquisition with the Neewer controller. Both worked perfectly.

---

Only a little over three weeks remain before the Nebraska Star Party. I've prepped three images for the astrophotography contest, one from Jeffers on the way to the 2014 NSP, one from my first night at NSP, and one from last fall. I need to give my binocular mount a couple more coats of varnish and it will be ready to go.

Goodbye to the AT72ED

Two years ago I purchased a used AT72ED. The scope I wanted was the AT65EDQ, but it was too pricey for my budget.

The AT72 was an able performer when paired with the Orion Field Flattener for Short Refractors (see my Andromeda Galaxy image in this blog post. I didn't care for the mounting foot, but it was easy to replace with rings. The focuser was no Moonlite but it held my heavy CCD + Filter wheel without problems. If it had a fault it was a little blue haloing on brighter stars. (I can't be sure if that wasn't my fault for not being a diligent focuser.)

Eventually a local club member decided to part with his AT65 and I was able to pick it up for not much more than the AT72 cost me. This made the AT72 expendable and I put it up for sale. I let it sit idle for a while on the club's merchandise forum. Finally this fall I listed it on Cloudy Nights and it sold along with the FF. The new owner is interested in using it to get into wide-field DSLR astrophotography, for which it's wonderfully suited.

The AT65 has been great this fall for chasing down the larger Astronomical League Bright Nebula objects. I recommend it to anyone who wants to get into imaging without spending a lot on an expensive telescope.

---

One of my telescopes is becoming something of an orphan. My old ShortTube 80, originally purchased as a travel scope to take to the 1998 Solar Eclipse in Aruba, doesn't have a role any longer. I'm holding onto it for now because it's still a good travel scope, and it's great as a guide scope. The Orion mini-guider has replaced the ST on my refractors, but I'm uncertain if the little scope will work well with my C925. That determination will have to wait for the summer when the weather is better.

---

Speaking of the weather, it's not been helpful. I got the usual fall head cold a couple of weeks before Thanksgiving. Then after the holiday the weather turned cold (frequently going sub-zero). I can handle temperatures down to around 10 degrees F, but zero is outside my optimal range of operation. Cold and Clouds have continued all December. I'm hoping for a better 2014!

---

Oh yes, one more thing. Astrobin did a major reworking of their site code and all my image links are now broken. I'll be fixing them as time permits.

Iowa Star Party 2013

Another star party, and continuing poor weather. This was probably the hottest ISP ever. Thursday: high temperature of 94F, dew point temperature of around 70F (heat index = 100F) Friday: high temperature of 97F, dew point of 72F (heat index = 106F) Saturday (the nice day): 91F and 61F, (heat index = 91F) Speaker's talk in the Barn: 86F and 66F (heat index = 88F) That was a very sticky 88! Some relief was found at midday on Friday in the Oakridge house, but unfortunately the A/C unit was unable to keep pace with the heat: it actually froze up. I bailed out around 3 P.M., preferring to face the heat outside where the air occasionally moved.

Friday was also public night, and the attendance was significantly smaller than I recall from my last visit. Between the heat and the fact that it was the opening night of high school football, it's understandable if people decided to be elsewhere.

And how about the sky? Thursday night was grand, although around 1 A.M. the south wind began shoving clouds northward and the southern sky started to deteriorate. Friday night was great for the public, but about the time they left the clouds moved in. The sky went partly cloudy during the early morning, but at 4 when I woke up it was about 50% cloud cover. Visual observers could deal with that, but imagers not so much.

Saturday night usable sky was all of  90 minutes pinched between the end of twilight and clouds rushing southward ahead of thunderstorms. It never cleared for any substantial time after that, and in fact around 3 A.M. a thunderstorm with heavy rain and gusts to about 44 mph (at Carroll) hit us. From what I saw the next morning no one sustained serious damage from the winds, although a couple of screened sun shades looked like they needed some repair.

Yes, imaging time was scarce, but I managed to get three objects in. Thursday night started with M8 and surroundings:

Messier 8, the "Lagoon"

Click this for a larger version. There are a number of objects here, not just the big old Lagoon. At lower left is globular NGC 6544. At about 10 O'clock from the lagoon and next to a bright double star is the pretty reflection nebula IC 5070. On the left edge of the picture about 1/5 of the way down from the upper left corner is emission/reflection nebula IC 4685. The lagoon itself is a confusing construct of NGC objects.

At this point it was a bit before midnight, and my sense was I didn't have much "awake" left in my tank. Some years ago at Jeffers I'd imaged M33 with my DSLR and TV102, so I  thought I'd try it here with the AT72ED and CCD. Here's the result:

Messier 33, the "Pinwheel"

The AT72 is really too short a scope for this object, but it was the scope at hand. I'm not happy with the color balance of this; judging by the star colors I'd almost say that the green channel is too strong. I'll doubtless reprocess this.

Friday night was clear for a while, and I was able to learn my target's star field while entertaining/educating the public. I  think I collected one frame before having to shut down.

Saturday I raced from the meeting barn to the observing field and was able to get everything running and my target composed in under 30 minutes (a not-so-minor miracle). In fact, I even had to toss my first light frame because it was still twilight. about 90 something minutes later it was over. The NA and Pelican are bright!

Nebulae NGC 7000 "North America" (left) and  IC 5070 "Pelican" (right)

Don't know why the stars bloated so badly in this one. Poor focus, most likely.  Clouds rolled in while there was still plenty of time for another image, so I count this as half a night.

Details for these images, along with their full-size versions can be found on AstroBin.

---------------------------------------------------
The last year's star party log sheet runs like this:

HOASP (Autumn 2012): three nights of rain.
WOW: Registered but did not attend; I would have had one good night at best out of three.
Jeffers: 2 good nights out of 3.
South Dakota: 1 out of 3.
Iowa Star Party. 1.5 out of 3

Add those up and it was 5.5 good nights out of 15. Disappointing. Perhaps this autumn will be better? If it is, I'll probably be making more runs to the club's dark-sky sites. Stay tuned.

Another Year, Another M42

I've imaged good old M42 a couple of times in the past with my DSLR and ST80. This is a more ambitious try, using my ST8300 monochrome CCD and AT72ED:

M42 (click for full size)

What's ambitious is that it's my first serious attempt at an LRGB image where I've given some thought about how to properly combine luminance and color data. This could definitely use a longer integration time--it was only about 15 minutes per channel at f/6, made worse by fairly substantial light pollution.

Notice those spikes coming out of the brighter stars? They're from overhead power lines!

The next clear night I'll try taking some shorter exposures so that I can mask in the overexposed center of the nebula.

Coming shortly will be a report on the Orion 50mm mini-guider. I will be using it for autoguiding on scopes of different focal lengths. It cuts about five pounds off my mount's load by replacing my ST80, which weighs about 6.4 pounds when guiding. This is particularly significant because that 6.4 pounds rides piggyback on my telescopes and has a substantial moment arm.

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!

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.

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.

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)?

Happily:

• 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.

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!

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.

New Scope Arrives

The new scope has arrived. The seller did a nice job packing it, and it's in beautiful condition. The only way to tell that it's used is a few clamp marks on the dovetail.

First impressions of the focuser suggest it's a great improvement over the GSO I've been using on my ST80. Tonight or tomorrow I'm going to reconfigure my imaging set up to have the AT72ED and ST80 side-by-side to see how it all balances out.

Of course, the forecast for the week ahead is clouds, clouds, and even more clouds. So don't expect a star test report, much less an image made using it anytime soon.

The Waiting Game: Dollar Days

No, I don't mean "Dollar Days" as in when a store offers a sale where most items are priced in whole numbers of dollars. It's a measure of anticipation and patience required when you've purchased something that must be delivered at a later date. I thought of this in 1978 when I ordered my first real telescope, an 8" f/6 Meade Newtonian on a GEM. It worked like this: The total cost was about $600, and the wait between placing the order and receiving it was two months (60 days). Multiply the two together, 60x600, and you get 36,000 $days. The larger the amount of dollar days, the greater the "anguish" of waiting you must endure.

I recalled this as I was checking the UPS tracking number on my incoming AT72ED. It has a price tag of $316 (including shipping, insurance, and a nudge for PayPal) and the wait is 5 days. That's a paltry 1,580 $days. Hardly even a mild test compared that old Meade.

Oh, and the telescope is black. I would have settled for any color. At night all telescopes are the same color, and all home-made telescopes look like they were made by a master craftsman.

Although I might have haggled a bit over the price if it had been the pink model from Astro-Tech. Pink would be a conversation started at star parties, which is fine. But I have a feeling that the pink models don't sell quite as well. I base this on the fact that some retailers call them purple.



A pink AT72ED

This doesn't look very purple to me, but pictures can be deceptive.  Have you see one of these in real life, and how does it look to you?

Yet Another Telescope

Telescope #5 joins the fleet.

For a while I've been looking for a better way to do wide-field astrophotography. I started by trying to use my ST-80 in this role. Its focuser (a replacement GSO model) just wasn't up to carrying the weight of my SBIG ST-8300M, and its optical quality was not very good. As I've mentioned in past posts, I looked at getting an adapter that would let me mount Canon lenses on the SBIG. That seemed a little too single-purpose, given the cost ($280).

Last night (Christmas Eve) someone put an AT72ED up for sale on Cloudy Nights, and I jumped on it. At $285 + shipping I hope it will be the most flexible solution.  It's a bit faster than my TV102 (f/6 vs. f/7)and much shorter in FL (432 vs. 700 mm). Its field of view is a spacious by 2.4 by 1.8 degrees. Questions remain: How robust is the focuser? How well will the Orion field flattener work with it? Commenters have noted that its focuser is much better than the standard 2" focuser by GSO. I've never read about someone pairing the Orion FF with this scope (most people use the AT or WO FF) so I'll have to find out for myself.

The seller is someone who just upgraded to an AT111 and apparently decided he could do without the 72. As for me, this will probably take the place of my ST80 as my travel scope. The ST80 now can retire to its role as Autoguider, for which it is well suited.

Next Telescope?

I enjoy wide field imaging, and it's easier for someone like me who is learning astrophotography. Tracking errors are less evident, and the hardware to image is smaller and less heavy.  The mount has an easier time carrying the load, and the smaller profile means wind presents less of a problem.

What should it be? I had my sights set on an AT65EDQ, a triplet with built-in field flattener:

Astro-Tech AT65EDQ

Typical Moonlight Focuser

But it seems to be no longer for sale, and if it comes back it will probably have a long period on back order.  The AT65's focuser is probably not capable of carrying my ST-8300M and filter wheel. So it almost demands a focuser upgrade, and that is expensive: Something like $400: Above is a high-quality Moonlight focuser that would be perfect.

When all is said and done, it's nearly $1,000.

Another option is to use the two Canon lenses I use with my XTi. This requires an SBIG adapter that costs $280:

SBIG EOS adapter for ST-8300 w/filter wheel

This covers the focal length range from 17 to 70 mm, which is shorter than I want. If one of these were to pop up for sale used, I'd probably go for it for full constellation imaging. Moog adapters used to be available for this purpose, but their business has been scaled back and because of the filter wheel, this would require custom work on their part.

I already have a field flattener for my ST-80, so any short-focus telescope is basically ready for imaging. What I want is something with a better than average 2" dual-speed focuser and focal length less than 430 mm. The model I've read about that seems to have the best focuser is the AT72ED; new this is $380 and used usually round $250-$300. Another scope is the Stellarvue SV70ED, which also gets very good reviews.

Astro-Tech AT72ED

Stellarvue SV70ED

I've put in a "wanted" post on my club's web site, and I'm watching Cloudy Nights and Astromart for used scopes and SBIG-Canon lens adapters.  I wonder how long it will take for something to show up.