Cabin Fever Dreams About Imaging IFN

Yes, it's mid February, the 2025 Nebraska Star Party mailing has arrived, and cabin fever is raging as temperatures are forecast to hit -18 F. Obviously that makes it a good time to play indoors with the imaging setup and ponder about the integrated flux nebula imaging I talked about last time.

The Setup

Here's a picture of the tentative setup that doesn't use guiding: 

Non-guiding setup

There's not much to it: camera, electronic filter wheel, lens, and "Frankenhub" for USB 3, power, and Dew control. This will be my "Version 1" to try at first. If it doesn't deliver adequate star shapes, I'll move on to Version 2 that includes guiding:

Same as in image above, but with guider swapped in for the hub

The hub will be a part of this, too. I'll attach it somehow to the underside of the dovetail or the G-11 saddle. This photo shows my old Orion StarShoot guider mainly because it can run off the ASI 2600's USB 2 port.

Note that in both setups the filter wheel limits camera rotation to a range of about 150 degrees, meaning there's a small (8%) chance I won't be able to get the exact composition I want. A suitable riser would fix this, so I may have to do some shopping.

I'm still eying that Rokinon 135 f/2 lens with a hefty measure of lust. Basic frugality stops me, and the truth is that I really am curious about how well the old Tamron lens performs for this task. The Tamron was about $90 in 1980; in 2025 dollars that's $342, close to the Rokinon's price before the tariff wars started up. While I've been writing this the price of the Rokinon has jumped from $368 to $409, an increase of 11%. 

PEC Training

This was a nice idea but after reading about what PEC is most useful for I doubt I'll bother with it. The focal length here simply isn't long enough for PEC to matter in any significant way. If tracking is fine unguided without training PEC, fine. If tracking isn't adequate I'll just use the setup that allows guiding. Many if not most commenters suggest that at short focal lengths guiding alleviates the need for PEC.

Guiding (if used)

The consensus seems to be that if one is using PHD2 and ASCOM guiding as I am (instead of ST-4) one should do PHD2 calibration by aiming the scope near the intersection of the celestial equator and the meridian. This is basically a do-once thing, only needing to be redone if you make a change in guider's orientation relative to the mount, such as rotating it around its optical axis. Once calibrated you can slew "anywhere" and it will guide properly.  I'm not entirely sure if it's possible to have guiding when aimed at a pole, or even at a declination like that of Polaris (3/4 of a degree from the pole). I'll find out if I decide to use autoguiding.

Dithering

Regardless of whether or not guiding is used, I'll want to dither. Even though it chews up some time I think it helps. If I'm guiding I'll try to use PHD2 dithering; if that works, fine. If not I'll dither with NINA. 

Acquisition

I would normally be tempted to use long exposures times for such a low surface brightness object like IFN. The problem is that long exposures tend to saturate stars; as a result, they lose their color. I want to keep that color as a contrast to the pale IFN. 

That means I'll need to use relatively short exposures of two minutes or less. Look at this image built from 90 s light frames to see what I think are ideal star colors. Yes, they're muted compared to what you see in a lot of images but I think they're more "natural" looking. (Never get me started on the rampant oversaturation of color in modern images!) 

Test images will reveal the optimal exposure length.

I'm going to shoot total exposure in the L:R:G:B ratio of 3:1:1:1. Maybe even 6:1:1:1. There's nothing magic about this, I just like to lean on luminance. That image I linked to was 1:1:1:1. Nice color, but not a lot of detail. More luminance might have helped. 

For convenience I'll probably shoot only luminance the first clear night under dark sky. That simplifies taking flats, focusing, and gives me some freedom about where I shoot the complementary color frames. Ideally those could get taken the second night under dark sky, but two consecutive clear nights in April in Minnesota? Ha ha.

If I only get one luminance night I can process that and see how well the IFN shows up in it. That will give me a sense of how much more is needed.

Any binning that gets done will be in post-calibration processing.

Composition

Using the celestial pole as frame center won't work well with NGC 188, which I want to include in the image. I'll ask NINA to put Polaris at frame center with NGC 188 in one corner. 

It should look sort of like this:

Planned IFN FOV (red box)

Combining Sessions

Given the hours of total exposure I'll want, this will certainly require multiple sessions scattered across several nights. This means I'll need to have NINA slew, center, and rotate consistently. Can NINA and my G-11 do this for a target so close to the pole? I'll have to find out.

Processing

Every new image brings new things to learn in processing. My Veil Nebula mosaic project taught me not only about mosaics, but also more about color calibration and background flattening. It also led me to acquire new tools like NoiseXTerminator, StarXTerminator, StarNet2, and the script StarReduction.  I expect this project will be no different!

The Weather

Camping may be deferred until May's new moon. Around the time of the April new moon the average daily low temperature is around 34 F. Great for keeping the camera cooled, but a little too chilly for this camper (I use a tent). Things improve in May, when the average lows are in the upper 40s. Still quite brisk, but much more bearable. I'll probably use April as my prep month, taking advantage of friend's warm house, and make camping reservations for May.

So that's my (over)thinking at this point. Before heading out to the state park I'll need to do a few things:

• See if NINA can slew/center/rotate for the intended composition
• Shoot some test exposures to assess unguided tracking, and switch to the guided version of the hardware if it can't. These exposures can also be used to judge exposure time, and if the lens suffers from distracting internal reflections
• Collect maybe a dozen or so frames of each color channel making use of NINA dithering and verify that star color is adequate
• It might be useful to verify that my stop-down ring is actually giving me f/4. This can be done indoors at any time using my flat panel

Aside from that last item all I can do for now is play with the hardware and wait patiently for warmer weather. Spring can't come soon enough!

Happy 2025! It's That Time Again: Imaging Plans for the New Year

It's usually folly to plan a summer of imaging. Sure, clouds and smoke could spoil things, but why not give it a  try? 2025 might just turn out to be an exceptional year! State Park camping and two star parties! Let's go!

APRIL/MAY

The first new moon of the 2025 camping season is on April 27th, a week after Easter. So any time within a few days of that should be dark enough for deep imaging. Likewise the dark moon in May, which may be better (i.e., warmer) for camping.

The late spring sky doesn't offer much to image at the focal length of my FSQ-106 (530 mm), aside from groups of galaxies and a few clusters. There is one wide-field subject that has always intrigued me: integrated flux nebulae, or IFN. Here's a nice summary of what IFN is and is not, and where to find it.

Probably the best known and most frequently imaged IFN is in the direction of M81 and M82. Instead of that I'll go for the IFN near Polaris.

Imaging near the north celestial pole has some interesting aspects. Because the apparent movement of stars there is so slow it's common for people to suggest not using autoguiding when imaging at relatively short focal lengths. To do without guiding you need a near-perfect polar alignment; a well-trained periodic error correction is very helpful, too. PoleMaster provides alignment that's close to perfect, so that's covered. But I do need to train PEC and that will be one of the first things I do this spring. 

Associated with guiding is dithering, which I like to do. Is it possible to dither and not guide? Yes, with NINA's built-in dithering. I'll have to learn how to use this, and hope it works well. If it doesn't I'll probably just not dither.

I've never targeted anything so close to a celestial pole; A little testing suggests that my G-11 is fine with having NINA slew from counterweight-down it to the pole. What I'm not entirely comfortable with is NINA trying to center it there; will it get lost making excursions back and forth across the meridian? Is Polaris far enough from the pole to make centering a nonissue? 

Regardless of where the target is there's always the question of what imaging gear to use. The key characteristics of IFN are that it's very low surface brightness and extensive in size. That sounds like a job for short focal length and fast focal ratio, right? Here are my best options for the optics:

• Takahashi FSQ-106 (FL 530 mm, f/5);  Pinpoint stars, but smallish field and rather slow
• Takahashi FSQ-106 + focal reducer, (FL 387 mm, f/3.65); Pinpoint stars, very fast, but smallish field
• Tamron lens, (FL 135 mm, f/4.0); Fits NGC 188 in field, overmounted (not a bad thing), very fast, no autofocusing

Here are two trial images made using the Tamron. An H alpha image of the Lambda Orionis Ring from 2015 and an LRGB image of the Sadr area from 2016. Both used an ST-8300 mono camera, and I can't say my processing was particularly good (I was still using ImagesPlus). How well it works with my ASI 2600 camera is unknown right now. Will it need spacers? Will there be tilt problems? Will it show internal reflections when put on a relatively bright star like Polaris? I won't know until the weather warms up and I can shoot some frames. 

If the 135 doesn't work out I might go with the FSQ + focal reducer. Its ability to support autofocusing is some compensation for its small FOV. Maintaining the FSQ's focus will be important for dealing with the long all-night sessions (6+ hours in April, about 4.5 hours in May). With a small lens like a 135, it's easy to minimize thermal FL change and prevent dew formation (as suggested by KathyAstro) by wrapping a long dew prevention strap around it. 

Finally, there's the issue of exposure time. I'll probably use my standard 120 s @ gain 100 for luminance and try to collect as many frames as possible. If tracking is an issue, I can drop it to 60 s, but if stars stay nice and round, I might increase this up to as long as 300 s. Shorter exposures will be fine for the color channels; in fact, those might only be 60 s  @ gain 0 to keep stars from saturating. Some experimentation is needed!

JUNE/JULY

The Nebraska Star Party typically occurs close to the end of July, a bit too late in the year for imaging my desired target of the Antares/Rho Ophiuchi region. In June the situation is much better, and a good time for imaging it comes after the third quarter moon of June 18. The Antares and Rho Ophiuchi nebulae should look fine together at 135 mm. 

July is wide open for imaging much of the Milky Way, including the M8/M20 tandem. This pair will fit nicely into a single frame using the FSQ-106 with its focal reducer. Also available is M16, which nicely fits the FSQ native field.

LATE AUGUST

It's Northern Nights Star Fest time, and I'll continue collecting frames for the Soap Bubble. Recall that the Bubble had just started to show up with about six hours of frames collected in 2024. Continuing on this target in 2025 should put me over 12 hours of total exposure. Barring losing time to more Aurorae. 😁

SEPTEMBER/OCTOBER

The Iowa Star Party (2025 date TBD) will be a good time to gather more frames for either the IFN, the Soap Bubble, or some other target that suggests itself. Another possible target is IC 348.

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Obligatory Power & Battery Update 

As an Amazon Vine reviewer,  I have been able to get the components needed to replace my old 100 W solar panel and charge controller with a smaller, much lighter 50 W unit. Thank you, Vine!

Today wasn't ideal (high haze and tree branches) but it managed to supply 35 W. The charge controller seemed to work fine, and in an hour it boosted a 10 Ah LiFePo4 battery at rest voltage 12.96 V to 13.26 V. The meter suggested 20 Wh had been added to the half-charged battery. That's compatible with the rest voltages.

The real test will be when the sky is fully clear and the panel gets hot in the sunlight. I'll take it camping and see what it can do.

December Update

Winter Break Begins

The first Arctic blast of the winter has arrived and it's time to shut down imaging until spring. I've sent my Losmandy Gemini II off for its Level 6 factory upgrade, packed up all the optical gear and put it in the driest part of the house for winter storage, and have discharged all my lithium batteries to about 50% of capacity. The latter is for optimal battery health during several months of non-use. They'll get a recharge and second draining around February, and then get a full charge whenever spring decides to happen.

This treatment regimen includes the smaller LiFePo4 batteries that I'll probably haul up to the 2025 Northern Nights Star Fest for swapping/selling. 

The endless mosaic

I've decided to do a full reprocess of the mosaic starting from calibrated frames. Three of the panels have new light frames and will need to be re-integrated. So for the sake of uniformity and to improve the processing workflow I'll do it all again. Isn't reprocessing what winter is for?

Getting back into spectroscopy

My last activity of autumn was assessing the use of my AT65 astrograph for spectroscopy. I'm really unsure about using an astrograph for this purpose, as I'm concerned that putting the grating so close to the OTA's internal correctors will lead to smearing of the spectrum. Little did I know this was going to turn into a multi-night struggle as the mount and focuser had issues. Fortunately there were a few clear nights for fiddling with the focuser before the weather got too cold for me.

I had already adapted my old Pegasus FocusCube 2 to my AT65's focuser, but I had done it incorrectly. I had attached it to the fine-focus shaft. This led to absurdly fine focusing precision--and sometimes demanded too much torque from the FC2 causing it to seize. Putting it onto the coarse focus shaft solved the torque issue, and made it possible to rack out a couple of centimeters without having to wait half an hour.

Whether the change results in focusing that's precise enough to match manual focusing is something that won't be resolved until the spring. That's also when I'll configure it for backlash and autofocusing.

Maybe this is why the AT65 never appeared on the FocusCube compatibility list?

Stay warm everyone! Happy Holidays!

FrankenHub is Created & A Very Minimal Power Supply

Okay, it was Halloween yesterday. In keeping with that I'll show you my replacement for the Pegasus Powerbox that died in Iowa. 

My Powerbox was a USB and Power Hub with the capability of controlling dew straps as well. My replacement would need to have those capabilities.

I already had a powered USB3 hub and a small Anderson Powerpole-based power bus from past tinkerings, so it was only a matter of replacing the dew control capability. A nice little Pegasus Dew Controller took care of that.  Yes, it's manually operated, but that's fine.

The USB Hub is so old it's no longer sold (not a surprise) and now is a 7-port, smaller device.

What was left was how to put it all together. And that's how it became Frankenhub.  I decided the perfect "suturing" was silicone bathtub caulk. Silicone caulk is waterproof, bonds to almost anything, remains pliable, and can be removed. As an adhesive it's more than adequately secure when joining two flat, clean surfaces.

Frankenhub is three layers, a dovetail to mate it to the ad-hoc finder shoe on the scope OTA, the USB hub, and then the dew controller on top:

Frankenhub

Definitely not as pretty as the Pegasus box, but it works just fine. What it lacks is software control of the dew controller, but I can live with that.

Wait, where is the power hub? Caulked to the side of my G11 saddle:

Power Bus

Think of this as one of those big bolts in the neck of Frankenstein's Monster. You know, these things:

OEM Heavy-Duty 300,000,000 volt / 30,000 amp Connectors

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Speaking of power, here's a minimalist approach to supplying power: A 50 Ah battery and cute 12 V distributer:

Power and Distribution

The battery has all the power I need for several nights of summertime imaging and the distribution box has three 12V automotive sockets, all I need to run my setup. Here's a closeup:

Power Distributor

Note that it includes a voltmeter that can be turned on/off, various sockets for charging your mobile devices, and a 3-level light that you could easily cover with red plastic.

The included 50 A Powerpole connector probably couldn't handle the 30,000 amps that jolted Frankenstein to life, but it's more than enough for my rig's peak draw of  5 amps.

 

50 amps of gray

Next time I'll have another Frankenstein that I hope isn't monstrous: the Veil Nebula mosaic, using parts (images) from a few sessions at Eagle Lake Observatory, The Iowa Star Party, and a friend's back yard near Stacy, Minnesota. A real Frankenimage. 

 

First Pass at the Veil Mosaic

I finally had enough data to make a very flawed Veil mosaic. Here it is at 1/5 scale:

Click for 1/5 scale image

And here is the link to download the full-scale image. You can use the cloud site's .jpg to look at it, but I suggest you use your own image viewer. Minor advisory, this is a large image, about 10K by 10K pixels and the file size is 12.5Mb.

You should immediately see some interesting things in the full image, some of which I'll detail here. I'll start with the major flaws (all the images below are at full scale if you click on them).

1) What's the big circular thing?

Bad Flat!

This is in the upper left mosaic panel, and results from improper calibration (using an outdated flat, rookie mistake.)

2) What's all that noise?

So Noisy!

Again in the upper left mosaic panel and comes from not only the poor calibration but also insufficient data.

3) What's with all the black pixels?

Pepper Spray

This is found in the upper and middle left panel; it results from pushing the panel a little too aggressively in one post-processing stage.

4) That green thing can't possibly be right!

Streaks to Left of Center: Not Really Green!

So far as I know there aren't any green nebulae. For reasons I don't understand this feature shows up rather strongly in the green channel compared to the red and blue channels; it's quite strong in luminance. I've seen one other LRGB image of this area, and it didn't have these green bits, so I must conclude something in my processing is at fault here.

The Dastardly 52 Cygni

There was one other flaw I had to skate around. I used the script Star Reduction from Blanshan and Cranfield to perform star reduction. It requires a starless image; this can be made either using StarXTerminator (aka SXT) or StarNet2. I used SXT, and it had a lot of difficulty with Magnitude 4.2 52 Cygni (see above image). It essentially suppressed the northern end of NGC 6960! So I switched over to StarNet2 and it handled things fine. 

Notice that StarNet2 didn't handle it 100% cleanly either, giving it what look like (but aren't) diffraction spikes. Looks kind of cool, I think, but then I grew up as a Newt user.

Now for some positives:

1) No seams. I used Photometric Mosaic, and not only didn't it produce seams, but it avoided the pinched stars that GradientMergeMosaic plagues me with. 

2) Color calibration by SpectrophotometricColorCalibration (SPCC). I can't say enough positive about SPCC. My old workflow made color correction very fiddly, with the result depending on how I felt the day of processing more than any sort of objective measure.

3) Not narrowband. For good reason the Veil is usually imaged in narrowband, but that results in false colors. It's nice to see things more as they "really" are (aside from a Green nebula).

4) Not oversaturated. In my opinion oversaturation is very common now. I've said before that a guiding principle of processing should be that less is more; this idea applies to sharpening, stretching, and also color enhancement. I did bump this a half step using ColorSaturation, but pushing it further seemed like too much of a good thing.

5) Reasonably sharp. Here's a neat feature at the south end of of the East Veil. This looks good thanks mainly to BlurXTerminator (BXT). In fact, aside from the one issue seen in SXT, I think the triad of BXT, SXT, and NoiseXTerminator (NXT) is difficult to beat.

An Optical Spiral That's Probably Not a Real Spiral

   

I suspect this curly-thing at center is nothing more than an undulation in a plane seen edgeways, but it does look fun.

So, with those issues listed above this thing obviously isn't done yet. The other night I shot additional light frames for the two panels that suffered from noise (along with same-night flat frames), and I think I can make sure that pepper spray of black pixels can be avoided.

This means doing much the processing over again, but that's life.

Iowa Star Party Imaging

I'm back from the Iowa Star Party! This is held each year at Whiterock Conservency; the observing field is located about five miles southeast of Coon Rapids, and 60 miles from the center of Des Moines.

2024 ISP had some differences from my previous attendances:

• This year's October party was much more pleasant than the steam baths provided by the usual summer dates. Every night had nice cool sleeping weather for us tenters
• The usual evening banquet wasn't prepared on-site and served in the picnic area; instead it was catered and held indoors at the very comfortable Bur Oak Visitor center. It was moved to lunchtime so that it wouldn't interfere with public night. The earlier time also allowed us to be at the field well before dark
• The field was in great shape, and the addition of a modern bathroom / shower facility was very welcome. I had the distinction of setting up farthest from the bathroom, so it was easy for me to get my daily steps in!
• Saturday night was clear, but the high winds during the day put a lot of dust in the air and really enhanced the brightness of local light domes, which have grown much more prominent in recent years. The low, very dark southern horizon may be thing of the past

But let's get to the imaging.

Friday night I was all set up, polar aligned, and ready. First target was Panel2 of my Veil Nebula mosaic, and the scope was doing its slew, center, and rotate thing. But it never finished because something was causing it to throw errors related to the mount control. 

The usual power cycling didn't clear it. What followed was several hours of swapping cables in and out and trying every other remedy I could imagine. Eventually I started to get the sense that the problem was my Pegasus Powerbox, so I recabled everything to remove it from the USB data flow (it remained acting as a 12V power hub, though). This worked, but it left me with no way to power and control my dew straps. Thank goodness it was as dry as it was, dew prevention was not needed that night or the next. 

To confirm where the fault was, I ran a USB cable to the Powerbox but did not connect anything to its output USB ports. The same errors returned suggesting that simply having the Powerbox as an active USB device was enough to cause the problem. 

I've read that the Powerbox can be harmed by connecting a 12V input line to its Adjustable Voltage port, and I know I've done that at least once recently. The poor Powerbox may have run afoul of Stupid User Error and had finally given out at ISP. Bummer. 

Anyway, I was up and running again and was able to collect light frames for my Veil mosaic.  I got everything I needed for Panel 2 Friday night, along with luminance for Panel 3 and a full set of flat frames. Saturday night I collected RGB for panel 3, along with some frames for the odd object seen in Panel 6 data.

Here is the Panel 2 LRGB result (click to see 1/4 scale version):

Panel 2 (NGC 6974, 6979, Pickering's Triangle, and the northern tip of NGC 6960)

Here is Panel 3: 

Panel 3 (NGC 6995, IC1340, and the Southern Knot) 

I've started to work on the full mosaic and noticed that my Panel 1 luminance frames were badly flatted and need to be reshot. If I can manage that this week, next time I'll have a first attempt at the full Mosaic!

Northern Nights Star Fest Featured a Wonderful Aurora; Trying to Image the Soap Bubble

I've returned from the Northern Nights Star Fest, where I had two solid nights of imaging. The first was cut a little short by a spectacular display of aurora, not that I minded at all. 

Most of the night the northern horizon had been aglow. Not terribly bright, but obviously there with occasional pulses within it. 

About 1:30AM the glow became much brighter and began to expand upward from the horizon. Soon it was bright enough to cast shadows and was casting pillars upward, starting with an intensely blue streak that was initially mistaken for the onset of a Steve event. By 1:45 intense upward pulsing had begun contained within a bright-edge envelope. Pulses were rapid bright and chaotic, and their areal extent grew to encompass the entire northern half of the sky. My impression of them was driving at high speed through very patchy fog, brightly lit by the car's high-beam headlights. The dominant color was the usual pale green, with some reds in more persistent bright patches closer to the horizon.

The impact of the aurora was quite evident in the stream of two-minute luminance exposures I was taking:

Mean pixel brightness during the imaging session.

Notice that in my impatience I started imaging at 9:18, well before the end of astronomical twilight (9:42) and you can see the sky continuing to darken through my 15th frame at 9:43.  At about frame 97 (1:02AM) the sky begins a slow brightening probably due to the aurora. At frame 101 (1:08) the brightening rate begins accelerating. 

I was imaging a 2.5 x 1.7 degree field centered on a point between the Crescent Nebula and the Soap Bubble in Cygnus. At 2 AM this was at about 53 degrees altitude directly west. The bright boundary (a curtain?) began moving through the field at about 1:53AM and took perhaps ten to twelve minutes to fully exit. Once clear of my FOV the field was full of pulsations which gradually weakened.

The period of intense auroral activity in the FOV is better seen in this expanded view:

Expanded view of auroral interaction with FOV; not the frame numbers have been offset by 120 for better legibility

By the end of my session at about 3AM the aurora was gradually dimming but still a strong source of natural light pollution. Because the aurora created nasty gradients as it crossed the FOV I'll have to discard those frames, along with others nearby in time.

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Oh, the image I was collecting data for is being processed (see first results later in this post). I don't have much hope for the target (the Soap Bubble Nebula next to the Crescent), so I'm processing the luminance first to see if I can see any sign of it. I have 118 good frames (not quite four hours) after tossing a handful of poor tracking frames and those around the time the aurora was bright.

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Other NNSF personal news:

This was the first time that I performed on-site collection of flat frames (and dark flats). I used NINA's built-in Flat Master to vary my light panel's brightness. This made it possible for all the frames to be one second exposures. Flat Master collects flat darks for all four LRGB channels. Since these are all at the same exposure time, three of the channels' flat darks are redundant. This means a little time wasted, but since this can be done during twilight no harm is done, and the extra files can simply be deleted.

Power consumption was about what was expected. With the laptop-specific battery powering that, the main battery handled the first night's 5.5 hours of mount, dew, and camera cooling with 163Wh. The second night's 4.5 hours consumed 136Wh.  This averages to about 30Wh per hour of imaging or a continuous power requirement of 30W, which is the number I wanted to determine for planning my energy use. 

Let's apply that to the upcoming Iowa Star Party in the first week of October to see what will be needed. That night there are about 9 hours 23 minutes available for imaging. Let's assume three nights of clear sky, so that's at most about 28 hours of imaging. Sounds great!  28 hours x 30W =  840Wh, which is about 240Wh more than my battery can provide. Therefore, I need either AC or solar for charging. Day length is about 11.5 hours, and let's assume the first and last two hours of daylight is unproductive. That gives 7.5 hours to get that 240Wh. That's 32Wh per hour of daylight if it's to be restored in day, or 16Wh / hour if in two days. I think a 50W solar panel should be up to this charge rate, so I've put my 100W panel up for sale. Now I just need to find a replacement in time for October!

UPDATE: I looked at what was for sale on Amazon and saw that the 50Ah battery I previously purchased was on special with an added dealer discount. By far the simplest solution is to bring a second battery and swap it in after the second night's imaging, or patch it into to my power box through the charging port so the two batteries can operate in parallel, providing almost 1.2KWh. Not only an amazon special, but a 10% off dealer discount, too. I went for it.

As for the laptop-aux battery, it was still at 13.3V rest voltage after the two nights, so it's unlikely to need recharging.

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Just registered for the Iowa Star Party, one of my favorites--when it's not crazy hot and humid as it almost always is when it's in late July or August. I've suggested to them that they might be better off holding it in September, and this year they finally moved it -- to October! The average highs then are around 70 and at night it drops to the upper 40s. That's my kind of weather!

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So how did that soap bubble image turn out?  I think "barely there" is the best I can say. Here's the full field at 1/5 scale:

1/5 field LRGB

Okay, Let's get rid of those stars and look at the central portion of the image:

This is a teeny bit better; the Bubble is at lower left, click to enlarge

It's clearly there and has a hint of the correct color shift toward blue, but it's still nothing close to adequate. 

This is based on 3.93 hours of luminance, and each of the RGB channels averaged close to 1.27 hours. What's this in terms of total exposure time? Adding together all the light frames (there were 233) that's about 7 3/4 hours of photons collected. To my way of thinking it's more like 5.2 (3.93 + 1.27) hours.  Whatever way you slice it, it wasn't enough, and double (or even triple) the time is going to be desired to make this look halfway decent. It might also be useful to take the luminance a little deeper. So maybe this will be the target for the Iowa Star Party?

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One last thing, it seems to me that Donald Trump has only one purpose in life: The feeding of his own Ego.  This is not unusual for politicians (see: Lyndon Johnson) but Trump pushes it to pathological limits. You saw in the "debate" how easily his vanity can be used to manipulate him. This is not a tactic invented by Harris; it's a lesson the world has learned from his interactions with authoritarians such as Putin. Trump envies his abuse of power and would seek to imitate it here, replacing the rule of law with the rule of the iron fist. Because I don't think the Grand Experiment of Democracy has yet to run its full course, I will not cast my vote for someone who seeks to sacrifice it to his need for self-gratification.

Oh, and Trump's policies, particularly toward women, stink.

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That's enough for this post. Have fun everyone! See you in October in Iowa!