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!

Pegasus FocusCube Version 3; Back from the Eclipse

Pegasus FocusCube Version 3

I've been using the Pegasus FocusCube Version 2 for a couple of years and it's been amazing. The only problem I ever had with it was my own fault; unknowingly I tried to run it a few times past the inward limit of my focuser and that loosened the shaft coupler to the point the FC2 lost track of where it was. When I'm not trying to torture the poor thing it has always delivered a sharper focus than I ever achieved manually. 

Pegasus recently introduced FocusCube Version 3, and FC3 has new features, only one of which really interested me -- it's USB 3 and only needs USB power to operate. My first thought was "wow, one less cable!"  

Instead I'm having to choose between two options: buying a new, big, $640+tax usb/power hub or kludging together my existing hub and an old powered USB hub. Of course my frugal nature demanded I go with the latter option!

Why?  The FC3 gives me three devices that require USB 3 power or communication bandwidth: FC3, ASI 120MM Mini guide camera, and ASI 2600MM Pro imaging camera.

Alas, my current USB hub, a Pocket Powerbox Advance Gen 2 has only two USB 3 ports. My delusional mind had assumed all four of the USB ports my existing hub (a Pegasus Pocket Powerbox Advance Gen 2) were USB 3. My delusion was reinforced by the mislabeling on the Powerbox case:

My Pocket Powerbox Advanced Gen 2 Collector's Edition with incorrect USB port label

The correct label can be seen on the Pegasus product page.

The kludge I'm putting together involves using Velcro to piggyback an old hub on the Powerbox. In the end this means instead of reducing my cable count I'm going to increase it by one. Oh well ...

On the other hand, NINA fired it all up without a glitch, so it's ready for imaging!

Moving The FocusCube 2 to the AT-65EDQ

A second reason for purchasing the FC3 was so my old FC2 could be installed on my AT-65EDQ, a small astrograph that can produce lovely images. 

I plan to use the AT-65 mainly to collect stellar spectra because the camera-to-scope connection must use a 2" nosepiece. A nosepiece makes it very easy to place a diffraction grating in the optical path. And at f/6.5 it's a little better for spectra than my FSQ at f/5.

The AT-65 isn't on the list of scopes compatible with the FC, possibly because of the diameter of its fine-focus shaft. The smallest shaft coupler provided with the FC3 was 4.0mm -- much too large for the 2.5mm AT-65 shaft. Unfortunately the smallest coupler I could find for sale was 2.3mm. (Maybe that  corresponds to some common non-metric size? I tried to file down the fine focus shaft, but it's made of an alloy harder than my files. I did find a nice attachment for my rotary tool that must have had emery or diamond on it, and that took the shaft down to size.

Both FCs are now working with Unity and NINA. Let's have some clear nights now!

Back from the Eclipse

We drove from Minneapolis to South Washington, Indiana.  Ten hours in rain to get there the day before, but it was worth it--almost perfect sky for the entire eclipse -- and most importantly at totality. The naked-eye prominence was worth it alone, and I doubt any image will be able to do it justice. 

Arriving a day early and leaving the day after meant no traffic problems.  This was my fourth eclipse (1978 North Dakota, 1998 Aruba, 2017 Nebraska were the previous) and probably my last. And I'm pleased to say I took no images, I just looked upward and enjoyed.

The fact that Texas was cloudy and the Midwest clear demonstrates perfectly the difference between climate and weather. 

 

A Brief Pause

The seasons have changed again, at least according to the calendar if not the thermometer. Despite the pleasant autumn I managed to be lazy and not haul my imaging gear out. I think an early cold snap convinced me it was winter. The reality is it's almost the new year, so time for a look ahead to 2024.

C9.25 and TV-102 back in service

As a last gasp of 2023 activity I did do a little bit of scope maintenance. First it was the turn of my old Celestron C9.25 to get collimated; I had cleverly manage to mess up its alignment to the point it was useless. This time I was very careful. Only small adjustments were made until I had it close to correct. I'll still have to do a finer tuning in the spring/summer when I can get the scope out under some decent stars.

The other bit of work was for my TV-102. Some years ago (nine? Amazing how time flies!) when imaging  IC 348 in Perseus, I noticed an irregularity in the flare around 4th magnitude omicron Persei. You can see it as a notch at about 5 o'clock.  

Omicron Persei with a mysterious dark notch

Here's a link to the full image on AstroBin. For comparison, here is Gamma Cas with my FSQ106, showing what a flood of starlight should look like.

Gamma Cas (FSQ-106EDX4)

The dark notch isn't awful, but it is a serious distraction. The primary suspect was something in the optical path. It was a simple thing to point the scope at a light surface and look through the objective from the focuser end. Clearly apparent was a sort of bump protruding into the circle of the objective. But what was it? Had something fallen into the OTA?

In the dangerous tradition of "monkey see, monkey disassemble," I took off the objective cell and discovered the problem. A bit of the TeleVue flocking paper inside the telescope tube had blistered up and gotten into the way of light. The fix was obvious to this monkey so I carefully filed down the petrified bump, put the objective cell back in place, and called it a done deal. 

Then something amazing happened: I had a thought. I wondered if I had gotten the cell back in place correctly, and was the scope still optically aligned? Dashing to the Internet I started reading posts about the travails people had collimating TV-102s. Also how they often had to fabricate clever jigs to do the alignment. Said jigs were far beyond my technical skill to create, so I was depressed. Not wanting to admit to myself that I might have made more trouble than I had remedied I set the scope aside and moved on to  imaging with my C9.25 (not yet misaligned), AT65EDQ, and eventually FSQ-106. I'd revisit the potential damage later.

Fast forward nine years to the other night when I put the TV-102 on the mount and actually looked through it at a star. It wasn't a complete star test, but at 90X Polaris A and B looked like pinpoints. At  450X racking in and out a touch gave decently symmetric airy disks. So maybe I got really lucky and it's fine. The old scope can rejoin the fleet now. I would like it functional for that eventual time when I return to visual observing. It works wonderfully with my 31mm Nagler Type 5 hand grenade, and to me it looks like the classic telescope. A picture of it from 2008 still graces the WhiteRock Conservancy (home of the Iowa Star party) web site.

AT65EDQ

After adding the FSQ-106 for imaging my poor AT65 has languished. It's an imaging scope that's corrected to provide astrograph flatness, meaning it's not a so great for visual use. Its FL of 420mm (f/6.5) is close to that of the FSQ with the 0.73X reducer (f/3.65 and 387mm) so it's somewhat redundant. But it is small and light and could easily sit on something less substantial than my G11. 

All it really needs to be a little sibling to the FSQ is electronic focusing, so that's what I'll be adding to it. And a nice Seahorse hard case for travel. Then I only need to rig a way to mount the Pegasus powerbox to it. More about that next time.

Veil Mosaic

I have all the data, I've been delaying processing until snowy winter hibernation mode starts. In the Twin Cities in a given year a "white Christmas" with 1" of snow or more on the ground has a chance of about 71%. But that won't happen this year!  The ground is bare and the forecast is for a record-warm 53 on Christmas Eve with a possible thunderstorm. The non-winter of 2023-24 is on track to continue into January.

When the snow finally arrives I'll start with a mosaic of the luminance data first to see what I've got, then repeat for each of the color channels.

 AstroBin Voting

I like to post my better pictures on AstroBin. It's mostly a vanity exercise but I think that posting technical details about images can be helpful to others. I know I've learned some things by seeing how other people acquire their data. 

Because AstroBin is a sort of social medium members are allowed to vote for images and there are best image designations. Some people complain that it's highly subjective, motivated by people trying to build their posse of followers, get votes in return, etc. All of that is possible but I don't care. It's fun, and I like it when I get up-votes. Although I admit I don't often understand why some of my images get more votes than others I've posted.

I've noticed something odd in the last year or so, though. Some of my dusty old posts that have been sitting quietly will suddenly get a flurry of votes from unfamiliar people. An example is this image of Jones 1 from 2015. Earlier this month it got four new votes within a few minutes of each other. Other people have imaged this object and created far better images than mine, so I have to ask why I got those votes.

Possibly it's people fishing for votes, but why would they reach back to an image from eight years ago? Why not take the time-honored approach of following someone so that they'll reciprocate and build your posse?  The near-simultaneity of the votes makes me think it might be something more devious.

Oh well, maybe the applicable adage is "don't look a gift horse in the mouth." So I say: Thank you  for your votes, mysterious time-lagged strangers! Maybe next time don't wait 8 years!

Back From the 2019 Nebraska Star Party

I was at the 2019 Nebraska Star Party for Sunday through Thursday nights and it could have gone better.

It's been a wet year in Nebraska and that means the usual mosquito herd is larger than normal. The first night, Sunday, there was only a modest breeze that faded around sunset; the herd emerged and immediately zeroed in on me. My bug spray was unable to hold them off and I was forced to retreat to a screened enclosure after obtaining only a polar alignment. No imaging.

Monday night had a partly cloudy hour, but Tuesday through Thursday Nights were all cloudy with episodes of rain. So for me NSP 2019 was a bust. At best I would have gotten one solid night had I been able to endure the biting.

I have a feeling that as the trend of increasing rainfall continues (thank you, global warming) this will be the case more and more often. That means it's time to adapt.

My thought is that if I can work from a screened enclosure I can manage even on those really buggy nights. This means I need an enclosure and a way to control my imaging rig from a distance of maybe 20 feet or so.

At present I control everything using a single USB cable from laptop to imaging rig. According to standards this limits me to about 16 feet between laptop and rig. Subtracting 6 feet for drops to and from the ground and I'm left with about 10 horizontal feet of separation, so I need to extend my USB. This can be done using powered USB repeaters, but that would mean added connections and power lines. the simpler way is to use an Ethernet extender like this:

This passes USB between two boxes via up to 60m of Cat5 or Cat6 Ethernet cable, with only the box on the rig requiring external power. Some serendipity: The required power is 12V DC and uses the same connector I'm already using with my USB hub on the rig. And the on-rig box acts as a powered four-port USB hub. The only drawback is that this is strictly USB 2, so if I add a USB 3 device I'm in trouble. This is available on Amazon for under US$60.

Focusing is not pleasant when you're being bitten, so a motorized focuser is needed. Unfortunately the only motorized focusers for an AT-65EDQ cost close to $1000 when all is said and done. This is a very nice little scope, but I'm not sure I want to spend that kind of money on it. A much less pricey option is a JMI Motofocus, but they have stopped making them for the AT65 and I could find no vendor who has one in stock.

Luckily some years ago I was given an Orion version of the Motofocus. It wasn't designed for the AT-65, but it was close. All I needed to do was add a small piece of aluminum sheet to it and buy a couple of longer bolts.  I made a nice long phone cord so that it can be used over a much greater distance than the coiled handset cord it came with.

The piece of aluminum (silver rectangle in the above image) is epoxied to the Orion-provided mounting bracket to extend it the required distance. The longer screws and small stacks of washers provide the needed offset to keep things square and allow the larger focus knob to rotate freely. Note that there is no clutch on this so while the motor is attached there is no manual focusing. If you need manual, just undo the two outermost screws on the bracket and replace the motor with the AT65's fine focus knob.

The last operation is one I can't really do much about: polar aligning. This will still require standing at the scope and adjusting azimuth and altitude by hand. Nothing is perfect :)


The final adaptation is a freestanding screened area that's large enough for setting up a small table and chair. I went with this one from Coleman:

This is available from multiple vendors for a wide range of prices. The footprint is a spacious 10'x10', so I'll even have room for a little lie-down while imaging. Despite this being floorless, it gets good comments about keeping the bugs out. We shall see. One thing, though--don't imagine that this is adequate as a sun or rain shelter. I purchased mine from Kohls.

So I'm now set for the mosquitoes. Unfortunately there's nothing I can do about clouds and rain, but that's always been the case.

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.

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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.

Some odds and ends for a Friday the 13th...

AL Bright Nebula Imaging Planning
I took some time to plan my imaging for March and the Messier Marathon night. The tentative lineup, all to be imaged using the AT65EDQ, includes four objects. The Cone Nebula (NGC 2264) and Hubble's Variable Nebula (NGC 2261) in a single frame. Both of these are Lynds brightness 1 objects and available from the onset of darkness until about midnight (3 hours or so) meaning I can probably do a nice LRGB of them. After that it's on to LBN 10, high enough for imaging until about 3 A.M., and  then LBN 1122, good from then until dawn about 2 1/2 hours. LBN 10 is a brightness 6, so it may only be L; 1122 is a 4, so maybe that will get the LRGB treatment. Dan Crowson's scheme is usually 12x600s for L and 8x300s binned 2x2 for each color channel, giving a total exposure time of four hours. I'll probably go with a much shorter plan; 12x300 L and 8x180 RGB (132 minutes) for the two bright nebulae; 20x300L and 8x180 RGB binned 2x2 for LBNs 10 and 1122.

If a miracle happens and we get some good weather in March, these plans could change to include more objects. Let's hope.

Good Luck
While planning the imaging around the Cone Nebula area I noticed that another AL Bright Nebula, LBN 943, was nearby. In fact, 943 is essentially a part of the Rosette Nebula, and it shows up in the image I had of the Rosette. I had overlooked this and failed to enter it in the "done" list. It's included now, pushing my total to 78. I wish they were all this easy!

NFeeder Progress
Not much in the last couple of days. I've designed the interface for setting up the camera, using the PHD command, and providing temperature control (including a programmed drop to the setpoint).

I've decided to split scripts into three pieces: general setup  before image capture; the imaging commands; follow-up commands (such as a slow warm up, disconnecting from the camera, and shutting down Nebulosity). I'm not sure if this is a good idea at this point.

The weather continues to misbehave
Cloudy and warm evenings punctuated by rare clear and cold nights. The long range forecast suggests no imaging for at least the next week, by which time February will be 3/4 past. Good riddance.

LBN 270 Mosaic

It's done. Spanning four nights (if you include one night's data that I eventually discarded because of poor focus), the four-image mosaic of LBN 270:

LBN 270

The irony of this is that I had to dodge a lot of clouds in order to image clouds. Only one night was clear for long enough that I was able to image two quadrants of the image.

Normally I would be imaging unbinned because of the short focal length used (an AT65EDQ at 422mm) and 5.4 micrometer pixels of the ST-9800M. Instead I did this by using 2x2 binning, which results in a speed gain by a factor of something like 3.6 (depending on who you trust as a reference). Each quadrant of the mosaic is based on about 20x300s light frames for a total time of about 6.6 hours.   

This is an object on the Astronomical League's Bright Nebula list. 

Speaking of which, a corrected list of objects that I made some time ago is now residing on the AL web site at:

https://www.astroleague.org/files/u3/BrightNebulaRev1.pdf

I might complain to the AL about getting no credit for this, but so far as I can tell they don't publicize this document.

The "official" list, still with errors, continues to be linked to at

https://www.astroleague.org/files/u3/BrightNebulaRev2.pdf

When is the AL going to fix this list? It's been over a year since the original posting of the list.

But enough about the AL, and more about the mosaic. I actually have two images I could append to the mosaic, one for IC 1318 (butterfly) and DWB 111 (propeller). The former is not oriented well, so I'm thinking that in a year I might revisit this and extend the mosaic down to Sadr so that it includes all of IC 1318.

But for now it's back to the list, and seeing how much binning helps tackle some of the dimmer objects on the list.

Time for Mosaics

I imaged many of the smaller/brighter AL Bright Nebula list objects in this season's sky last year, so this year I'm left to clean up the more difficult objects. These can be more demanding in terms of the sky I have to work with (tree-locked and bright), or by virtue of their larger size. In the former category are reflection nebulae and Lynds brightness category 6 objects.

Here's an example of the former, IC 4954 in Vulpecula:

This was shot in H alpha because it has a weak emission in that, and the narrowband filter helped to reduce the light pollution and moonlight. This is given a 2 for brightness.

For faint there's DG 191, shown in the previous post. There's no official brightness for this, but I estimate it as a Lynds 4. Most of it is visible in weak Ha emission, but the lower right quarter or so has a substantial reflection nebula component. Because I wanted to catch the blue tint I shot this in RGB. I should have gone with HaRGB, but I wanted to complete this in one night.

Sh 2-134 was too large for a single frame at 400mm. I combined two images to create a minimal mosaic using Photoshop:

I used Photoshop's default settings for this and it turned out pretty well. There is a transition line visible along the top of the lower frame, so it could use some reprocessing.

Next up is the huge LBN 270 (3 degrees across) in Cygnus, which will require a 2x2 mosaic. I managed to get the southwest frame last night during a couple of hours of clear sky!

Eventually I'd like to patch together a mosaic of Sh 2-240 (Simeis 147 in Taurus), a large supernova remnant in Taurus. That might take five or six frames!

Sh 2-137

The list rolls on with another faint nebula: Sh 2-137 in Cepheus. This object its also known as LBN 498 and has a brightness value of 5

This images represents 3.5 hours of integration on a night with a bright waning gibbous moon.

Sh 2-137

The bright star at left is GSC 04271-2621 with magnitude 4.57.

Imaging Targets for This Summer's Star Parties

I'm probably going to four star parties this summer: The Jeffers Starry Nights (JSN), the Nebraska Star Party (NSP), the South Dakota Star Party (SDSP) and Iowa Star Party (ISP). I'm hoping to do quite a bit of imaging at these, taking advantage of the dark skies and slightly more southern locations. It's not much, but every degree of elevation helps!

I'd like to bump along my Bright Nebula list work, and take a couple of pretty pictures, too.  The dark locations let me image reflection nebulae that I can't get from my light-polluted back yard. Another constraint is that whatever scope I bring to Jeffers will also be the one I use at NSP. So what should I image?

(1) I'd like to go really deep on the Iris (NGC 7023). It's a reflection nebula on the list, and it's pretty. Near by are some barely luminous clouds. A wide field shot with my AT65 will take them all in. The Iris a better target during the JSN/NSP time period than in late August. This would be a multi-hour object, to say the least.

(2) I've always wanted a good image of the Helix nebula (NGC7293). This is better imaged around labor day, so it should be during either the SDSP or ISP. ISP has darker southern sky, so that's where it will be imaged. The C925 produces a nice image scale for it.

The Helix from 2009 JSN.

The above is my only Helix image, taken using my TV102, an unmodded Canon DSLR, 16 x 180s @ ISO 1600. Not at all adequate. A few hours (or longer) of LRGB could be much better.

(2a) Other objects I would like to go really deep on are the Ring--see a previous post about the outer shell-- and the Dumbbell. Those would be best in the C925.

(3) I have only one so-so image of the eagle nebula (M16) from a couple of years ago. Unfortunately it doesn't include the portion of the nebula that's considered LBN 68, a list item. So that should be reimaged from a dark site. This would probably look better in the C925 but the wide field of the AT65 would be adequate. Best during JSN/NSP.

(4) There are a good number of large list items in Scorpius and Sagittarius that would image well in the AT 72. These should be imaged at JSN/NSP. These include Sh 2-13, 2-16, NGC 6334, IC 4628, IC 4701 and LBN 52. An hour each should produce images that could satisfy list requirements.

So there you are:

• JSN and NSP get the Iris and the large list items. This means that I can travel to them with the smaller, lighter AT65. One pretty picture (Iris) and a flock of list items.

• SDSP and ISP get the Helix, Ring, Dumbbell, and whatever else comes along. For those it's the C925. Pretty pictures all, and perhaps list items left over from July.

Now it's all up to the weather!

Another Obscure "Bright" Nebula: LBN 185, and IC 1470

The AL Bright Nebula list has quite a few not-very-bright nebulae on it. Here's one that's bright enough to image from a red zone + a nearly full moon: LBN 185 in Cygnus, a 5 on the LBN brightness scale.

LBN 185

I believe LBN 185 is the bright area near the center of the image. There's another bright area at the left edge of the image, but so far as I know that has no designation. This took 3.8 hours of H alpha imaging, and even at that the background is still rather rough. A couple of nights before I also got this image of IC 1470:

IC 1470

On the other hand, IC 1470 is bright, and small. This was taken with a C925 at a focal length of 1480mm, while the LBN 185 image is wide field with a 422mm AT65EDQ.

Finally!

This is the first image of the year! Let's just say it's been a bad year. Amazingly everything worked smoothly, including me. This is yet another AL Bright nebular object, LBN 331.

A so-so picture, but I'll take it--LBN 331 is a brightness 4 object, so given my skies I don't expect much from 1.6 hours total exposure.

LBN 331

Details are here.

Tonight's supposed to be clear again (we'll see), so with luck I can bag another object, or go back to this one and shoot some RGB so that the stars have color.

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.

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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.

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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!

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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.

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.