First time out for 2008 and first time in over 1.5 months due to constantly cloudy weather. This is also the first time I am testing the replacement Meade DSI Pro II CCD camera (which I received on Nov. 27, 2007).

Clear with some clouds, no wind, very cold at minus 12°C. The observatory roof was partly frozen, but I managed to open it. When I turned on the LX200GPS scope, the display on the hand box was all garbage, although the mount booted properly. I shut the mount off and tried again, and this time the display was fine.

I took images of M42, NGC 1977 (Running man nebula), M1, and M35 with the Orion 80ED at prime focus (600mm).  The images are fine and it appears this camera is working well.  There are many dust spots on the images and I did not bother taking flats, so the images are spoiled.

The air temperature decreased thru the evening and by the time I shut down, it reached minus 16°C!!
While I was closing the observatory, the computer failed (due to the cold) and was re-booting itself  continuously.  The CCD camera reached a temperature of minus 9°C.

The sky cleared completely around mid-afternoon and remained perfectly clear for the duration of the eclipse (but eventually clouded over around 2 am).

I opened up the observatory around 7:30 pm and had to rush to setup everything. I used the Canon A75 digital camera afocally using a bracket to hold the camera lens up to the eyepiece.  This method did not work well on the 10-inch LX200GPS with the Meade 26mm eyepiece because the camera would only see a small portion of the field of view.  I then switched to the Orion 80ED with the Meade 26mm eyepiece and that gave a good image scale, so I used that setup for taking photos.

I operated the camera with the computer via USB cable using the Canon software that came with the camera. The software is great, I just wish it gave a larger preview window.  Because the preview window was only about two inches square, it was very difficult to focus the camera. Initially I let the camera figure out the exposure and the focus, but then I switched to completely manual operation because that gave me the chance to try a variety of exposures and focus points. I also used the “vivid” setting because it gave a richer colour to the reddish moon.

All the equipment worked flawlessly even though the temperature was steady at minus 12C for the duration of the eclipse.  The camera batteries ran out at about 11:10 pm, but by then totality was over.

The eclipse was not very dark and the southern limb was brighter than the rest of the moon.  The partial phase started around 8:40 pm, and totality was from 10:00 pm to 10:50 pm.  The neighbour’s large cherry tree in the south-east was blocking the moon till about 9:00 pm.  Even though I could have operated the camera from inside the house (via wireless network), I wanted to see the eclipse and stayed outside in the cold.  

The photos I took turned out well, but I think they could have been a bit sharper. It was quite difficult to figure out the best focus even though I took a series of test images a different focus points. The exposures and colours were perfect. Closed the observatory at 11:15 pm since it’s a weekday.

Walked into the observatory at 7:15pm and by 7:30pm I was ready to image. The temp is 0°C, no wind, pleasant, but hazy with 85% humidity. The Sky Quality Metre (SQM) is about 17.4 due to a nearly full moon (it's usually 18.4 with no moon).

This is the second time out with the DSI Pro 2 camera and everything seems to be working quite well. No software or hardware issues of any kind, just lost of dust motes on the CCD chip. I am imaging at prime focus on the Orion 80ED which requires an extension tube to reach focus.

I tried cleaning the CCD chip with a brush but that only moved the dust motes around.

Took images of M42, NGC 2237 (Rosette Nebula), M1, and M35

Opened the observatory at 19:30, quite clear but quarter moon, temp is minus 4’C, some wind. Tonight’s setup is the DSI Pro II through the 10-inch LX200GPS with the F3.3 focal reducer. I also have the DSI pro ready to go on the Orion 80ED.  Controlled the scope and CCD camera remotely from inside the house via wireless network.  Earlier today I cleaned the CCD chip so the goal tonight is to see how well I cleaned the chip.

Tonight I imaged NGC 1977 (Running Man nebula), M1, M105, M95, and M96.  I also tried Comet 110P/Hartley but nothing showed up.  ECU said it should have been mag. 14.5, which is well within reach, but no luck.

The CCD chip cleaning went well, with only one dust spot remaining. The main problem is that the F3.3 reducer (set up for F3.3 using the 15mm extension tube) is causing elongated star images at the edges (this is called coma).  This renders the F3.3 reducer unusable with the 15mm extension tube.

At the end of the session I took flats using a lamp shining on the observatory wall. The wall is a light brown so it’s not the best setup, but they still helped a bit. There’s still a bit of a gradient left. 

I opened the observatory around 21:30, fairly clear, there might be some haze, about minus 4°C, 55% humidity, full moon.  I setup the DSI Pro II on the 10-inch LX200GPS with the F3.3 reducer and no extension tubes, thus resulting in a focal ratio of about F5.

With this configuration stars are sharp edge-to-edge, as opposed to using the 15mm extension tube, which resulted in coma around the edges.  However, I’m getting significant vignetting with this setup. There’s so much vignetting that the images are unusable unless I apply flats.

I was controlling the equipment from inside the house, however the wireless network kept cutting out which slowed me down considerably.

Show a flat image with the 10-inch and F3.3

I was frustrated by the large amount of vignetting so I went back to imaging through the Orion 80ED.
I later realized that the full moon was exacerbating the vignetting!!

I took test images of M65 with the DSI Pro II with the F3.3 reducer and no extension tubes, thus resulting in focal ratio of about F5.0, and unfortunately I am still getting lots of vignetting like I did on March 22.  I removed the F3.3 reducer and went straight through the scope at F10 and the vignetting was gone!  Looks like flat fields should be able to take care of this problem, but for the rest of the night I went back to imaging thru the Orion 80ED.

Show images of M65, M66 and M5. The images have flat fields applied, which I took the next day.

My flat field method:

With the observatory roof closed, I point the telescope at a white board, which is illuminated by a 60W light bulb from a desk lamp.  The desk lamp is position so not to cause any shadows on the white board.  I then cover the telescope with four layers of thick white fabric.  The white fabric diffuses the light and I use four layers because my bulb is so bright!

Before I begin taking flats I take darks, so that the flats will have darks applied.  Apparently this is an important step because the darks include a bias frame!  With the above setup and the Orion 80ED at F7.5 with the DSI Pro II, I found that an exposure of about 2.8 seconds to 4 seconds was fine for the flats.  That gave me a histogram reading of 25000 to 36000 ADU. Either worked equally well.

Completed the installation of 130 feet of CAT5e cable to the observatory.  The wireless was too unreliable and slow, so I decided to go wired – I wish I had done that from day one!  The cable runs mostly along the side of the house (so it’s exposed to the elements), however I purchased outdoor grade cable, so it should be fine for a few years.  The cost was just $0.85 per metre at Home Depot.

The connection speed is 100 Mbps, however due to transmission overhead, I tested the actual throughput at about 66 Mbps to 71 Mbps.  Although that appears to be pretty low, I found out that it’s about right.

Opened the observatory in the early evening, but only went out to image at 22:30.  One of the roof bolts ceased due to rust and would not come out, making it impossible to open the roof!

The only way I got the bolt out was to remove the wood screw insert, except that poked a half-inch hole in the plastic roof panel!! This can be fixed, but I certainly did not need the extra work.  Lesson learned – lubricate the roof bolts regularly to prevent rust build up.

The night is hazy, about 14°C and just 55% humidity, but the quarter moon is bright. The seeing is bad because it’s difficult to get a sharp focus.  I started by taking darks since I don’t have any at this “higher” temperature.  The CCD temperature is about 23’C.  I am using the newly released Meade Envisage software version 7.05, which worked well all night.

Tonight’s setup is the DSI Pro II camera on the 10-inch LX200GPS with the F6.3 focal reducer.

Here’s the only image I took tonight. M3 globular cluster, 57 images x 15 seconds each, total exposure was 14.25 minutes.

I was not pleased that of the 90 frames I took, I could only use 57.  Even with 15 seconds exposures the mount was not tracking very well.  I wonder if this was a result of the removal of a counter-weight that was on the east fork arm.  I removed that counter-weight because I felt it was putting too much strain on the RA drive.  I’ll put it back next time and see what happens.

Opened the observatory at 8pm, clear with some clouds, windy, temp is about 16°C.  I setup the DSI Pro II on the 10-inch at f6.3, while the DSI Pro was on the Orion 80ED at prime focus for guiding.

I took sky flats before it got dark using the "t-shirt" method. Each flat is a stack of 20 sub-exposures, dark subtracted. The best flat was 4 second exposures with a histogram of about 30,000 ADU.

At 9:54pm I saw the International Space Station fly over at mag. -2.2.

I imaged M3, Comet McNaught C/2005 L3, NGC 6166 (Abel galaxy cluster), M13

I used Envisage for guiding with 0.5 sec exposure and correction gain 0.5. I was getting x axis errors of 0.8 to 1.2 which caused trailing in many images. I tried a variety of guide exposures and correction gains but none worked much better than the others. Note that Envisage crashed twice while invoking autoguiding.

Opened the observatory at 9:30pm, quite clear, no wind, temp is 13°C, 50% humidity.
I double checked that PEC was on, anti-backlash setting for RA and DEC is 1% which seems good. I suspect PEC needs re-doing because it was last done on June 22, 2007 without the Orion 80ED piggy backed on top of the LX200GPS. The Sky Quality Metre (SQM) is 18.4 overhead, 18.5 to the north-east, and 17.9 to the south and west.

I setup the DSI Pro II on the 10-inch at f6.3, while the DSI Pro was on the Orion 80ED at prime focus for guiding.  Guide exposure is 0.7 sec and correction gain is 0.6. I tried other guide exposures and correction gains, but no improvement to guiding performance.

I imaged M64 and M51

I opened the observatory early around 8:30pm to take sky flats, but the sky is still too bright. Warm, no wind, 22°C.  I was able to take LRGB sky flats at 9pm using two thick layers of white fabric in front of the scope (to diffuse and dim the light).  All flats are 20 second sub-exposures, dark subtracted, and have a histogram of around 30,000 ADU.

I changed the DEC anti-backlash setting from 1% to 100% and it seemed more responsive. Then I set it to 75% but I could not detect any difference from 100%.

At midnight the Sky Quality Metre (SQM) was 18.3 to 18.1 to 17.9 depending where it's pointed in the sky. Even visually I could tell the sky was not as dark as last night.

The goal tonight was to acquire RGB data for M51. I setup the DSI Pro II on the 10-inch at f6.3, while the DSI Pro was on the Orion 80ED at prime focus for guiding.  Guide exposure is 0.7 sec and correction gain is 0.5. I tried other guide exposures and correction gains, but no improvement to guiding performance.

Show good image of M51

I opened the observatory at 10:30pm, quite clear, 15°C, low humidity, windy, no mosquitoes!
The purpose of this session was check my polar alignment, then experimenting with guide exposure times, and possibly re-doing PEC training.

I used the CCD drift alignment procedure described here:
using 2min 5sec exposures on a star at the meridian at zero DEC and on a star on the west near zero DEC. Both showed a perfect polar alignment!  (hard to believe!)

I then imaged M5 using 30 second exposures with the DSI Pro II and the 10-inch a F6.3.  The 80ED was guiding with the DSI Pro using Envisage using exposures of 2 sec and 2.8 sec and correction gains of 0.5 or 0.6 or 0.75 but none of these resulted in good guiding.

Lastly I did new PEC traning using the 80ED at 600mm focal length, using 1 sec guide exposures. The new PEC did not seem to help with guiding.

I opened the observatory around 11:30pm. Clear, no wind, 18°C, a few mosquitoes, waxing gibbous moon. The purpose of this session is to try to improve tracking and guiding by performing several prerequisite steps.

I "lapped" the RA gears 3 times by manually pointing the scope east and using the hand box to slew the scope west. I used the slowest speed. This step is supposed to get the RA worm and RA gear to mesh better.

I trained the RA and DEC drives on a nearby house chimney (less than 100 feet, so I'm not sure if that's too close).

Set anti-backlash to 1% for RA and 100% for DEC for best response.

I setup the DSI Pro II on the 10-inch at F6.3 for autoguiding with Envisage. I tried a variety of guide exposures and correction gains, but none seemed to work well. Also, Envisage kept crashing each time I tried to re-calibrate... very annoying. Eventually I chose a guide exposure of 1 sec and a correction gain of 1.0 (very aggressive), and started a new PEC training session.

With the new PEC active, I tried autoguiding again and watched the x-axis error, but it was still bad. I tried guide exposures of 4 sec to 0.5 sec and correction gain of 1.0

Next I tried changing the guiding rate (this can be adjusted on the Meade hand box). The default is 66% and I changed it to 99%, then 75%, then 40% along with a 2 sec guide exposure and a variety of correction gains, but nothing worked well. The x-axis errors are still in the range of 1.0 to 4.0 pixels. The goal is not to exceed 1.0 pixels.

Then I turned off PEC and tested again. Little difference. I wondered if PEC was even working before!

At 4am I started doing another PEC training session but clouds rolled in and I lost the guide star. Quite by 4:30 with morning twilight well in progress.

Opened the observatory around 9:15pm, mostly clear, some clouds, temp 18°C, 70% humidity, no wind.  The purpose of this session is to check the various mount settings and re-do PEC training. Steps taken were:

Put weight on east fork arm
"Lap" gears again at higher speed (set on 7) - see above for an explanation of what this is.
Set guide rate back to 66% (was 40% from last night)
Check anti-backlash: RA is ok at 1%, but changed DEC to 50%.
Re-check polar alignment via CCD drift-method - it was fine
Reset PEC to factory default (ie zero)

I setup the DSI Pro II on the 10-inch at F6.3, guiding with Envisage. I tried a variety of guide exposures (0.5, 1, 2, 3, 4 sec) and correction gains (0.5, 0.6, 0.8, 1.0) but none gave good results. The "least worse" was 1 sec exposure and correction gain of 0.8, so I used that for PEC training.

I did four PEC training runs using Andrew Johansen's MyScope application.  Here are the four curves:

Envisage crashed twice while autoguiding.

The asterism Markov 1 is described in the July 2008 issue of Sky & Telescope page 80.

 

Traveled to the Carr Astronomical Observatory near Collingwood, Ontario for some dark sky observing. This is the RASC Toronto Centre observatory and house. I decided to give imaging a break so I took my 10-inch SkyWatcher dobsonian instead.

Started observing at 10:30pm, some clouds, windy, cool, no mosquitoes. The Sky Quality Metre (SQM) reads about 21.30 (back home in the city it reads 18.5 on the best nights). The light pollution from Collingwood in the north-east is quite noticeable, as well as in the south-west, probably from Orangeville.

I looked at some "old friends" like M27, M71, M57, M13, NGC 6207, M51, and M101. All are amazing from a dark sky, especially M13 which is resolved to the core. M51 and M101 are both impressive because they are lager than I'm used to seeing them. Both M51 and M101 are visible in the 8x50 finder!

I also did a sweep of the Milky Way and got great views of M8, M20, M16, M17, M24, M22, M28, M11. Later I also checked out M31, M32, and M110.

Tonight I star-hopped to 5 new deep sky objects: NGC 5422, NGC 5443, NGC 5475, NGC 5585, NGC 5631. All are galaxies in Ursa Major.  I was not able to see NGC 5430 and NGC 5376.

In preparation for Starfest, I added ebony star laminate to the bottom of my 12-inch dobsonian rocker box. There was so much stiction with the original material used by the manufacturer that the azimuth motion was not smooth at all.

In the evening I looked at several Messier objects from the deck and even at high power I was able to move the scope smoothly in azimuth - what a great improvement!  I had not used this scope in such a long time that I had forgotten the great views it gives.

The purpose of this session was to test my old Meade LXD500 mount with the Orion 80ED scope for imaging.

Since the LX200GPS is currently not in the observatory, I was able to setup with LXD500 mount near the pier without interference (see photo I took).  I was able to see Polaris even though the tripod was not fully extended (I was afraid the mount would have been too low and the observatory wall would have blocked the polar finder). I powered the scope using the LX200 GPS power supply (same connector!).

The sky is clear although there may have been some haze. Some wind, however the scope is completely protected by the observatory walls. The temp was about 18°C. I set up in the early evening and ready to image by around 10pm. 

M27-1
30sec x 63 exposures
80ED at prime focus, DSI Pro II
Many trailed images, image is shifting left (east) and up (south). 

Disappointed with the tracking of the mount.  It appears my polar alignment is bad because the northward drift is severe.  Also, the tracking rate is too slow because the images have a severe shift to the left (I have to press the west button to re-center the image). 

I read the manual of the Meade 1702 drive corrector and I see that it’s possible to set custom tracking rates!  So, I increased the tracking rate by 3%.

M27-2
30sec x 50 exposures
80ED at prime focus, DSI Pro Ii
Still many trailed images, image is still shifting up (south), but it’s now shifting right (west), so the tracking rate is too fast. Try 2% or 2.5% next time

I also tried to connect the RS-232 cable to the “autoguider” port of the Meade 1702 drive corrector and using ECU software to connect to the telescope, but no luck.  When I plugged in the jack the scope started slewing south, so it looks like some pins were shorting to make it move that way.  The RS-232 cable RJ connector will not fit into the “handbox” jack because it’s too large.

The plan was to leave on Thursday morning (Aug. 7) as usual, but I postponed the departure due to thunderstorms. I left the house on Friday Aug. 8 morning.  On the way up there were three separate downpours.  I arrived at the campground at 12:10 pm under mostly cloudy skies.  Set up in the usual spot just south of the main tent which was already quite busy with other campers.  Raymond Li, Dave MacDonald and Peter Lukic camped next to me.

On Friday afternoon at 3:30 I gave a presentation called  “Backyard Observatory Construction” in the small tent.

Although Friday afternoon was overcast, the sky cleared around sunset and we have great observing weather.  See the observing notes below. I got to sleep around 3:30 am but around 5 am I woke up because I was very cold, despite the supposedly "minus 7ºC rated" sleeping bag and a thick red wool blanket.  The temp outside was about +12ºC

Rain woke me up on Saturday morning around 9am.  I rushed outside to cover the telescopes with plastic bags, then I went back to sleep.  It rained pretty much for the rest of the day with cool temps (around 16ºC).  I did not attend any other presentations on Saturday because there were very few and none were of interest to me. Because of the relentless rain I did not see any of the vendors and I did not roam around the campground.

Since the forecast called for clouds and rain, I packed up everything in the early evening and left at 8:40 pm. 

The sky cleared around sunset as expected. I setup the 12-inch dobsonian, as well as the Orion 80ED on the Meade LXD500 mount.  The temperature started dropping quickly and dew started forming during twilight. The low temp during the night reached 12°C.  We looked at a variety of Messier objects with the 12-inch and the 80ED. The first quarter moon was quite bright and washed out the sky till it set around 11pm.  After the moon set I think I could just barely see M33 with the unaided eye. The 12-inch dob has a focal length of 1500mm and it's about F4.9

I observed 8 new deep sky objects: NGC 3945, NGC 3978, NGC 3894, NGC 3895, NGC 3835, NGC 3809, NGC 4036, NGC 4041.  All are galaxies in Ursa Major.  I failed to see NGC 4081.

The faintest galaxy I saw tonight was NGC 3895 at magnitude 13.1. It was very faint and averted vision was necessary to see it.

Opened the observatory at 10:30pm, bright gibbous moon, 16°C, no wind, quite hazy, 77% humidity.
The purpose of this session is to re-do PEC training after I rotated one of the RA transfer gears. Before starting, I had to re-initialize the "finger printing" using the application MyScope. Tonight the Orion 80ED is not mounted on top of the LX200GPS.

Using the DSI Pro II on the 10-inch at F6.3 I did PEC training with the Envisage software. Guide exposure is 2 sec, correction gain is 0.8, guide rate is 66%. RA anti-backlash is 1%, DEC anti-backlash is 50%.  Tracking in the x-axis shows large error from +4 to -4 pixels (the goal is +/- 1 pixels max).
The resulting PEC curve is nearly identical to the one from June 21.

Bottom line: rotating one of the RA transfer gears had no effect on PEC.  This indicates the transfer gears are just fine.

Opened the observatory at 11:30pm, mostly clear, 14°C, no wind, 80% humidity, full moon.
The purpose of this session is to try PHD guiding (instead of Envisage) and learn how to use it.  I used various settings on PHD but the result was little difference in guiding accuracy compared to Envisage. Also, turning PEC on and off seems to make little difference. Has to stop by 2am due to clouds.

Opened the observatory around 10:20pm, hazy, 20°C, some wind, full moon.
The purpose of this session is to try more PEC training.  Went back to Envisage with 2 second guide exposures and a correction gain of 0.8.  I got a very similar PEC curve as last night.  Clouds rolled in so I had to stop.

This afternoon I swapped the RA and DEC motors/gear boxes in hope of improving my tracking and guiding.  The theory is that perhaps my RA motor / gear box is a bit inaccurate, so swapping it with the DEC motor / gear box might solve the problem. The job took about 4 hours (going slowly and taking a couple of breaks) and the scope worked well after the procedure. Note that after this work a finger print reset is a must and can be done with the application called MyScope

Opened the observatory around 8:45pm, very warm at 20°C, very hazy, some clouds, full moon.
Did PEC training thru the 10-inch at F6.3 with the DSI Pro II camera, using Envisage with 2 sec guide exposures, correction gain of 0.8, and a default guide rate of 66%. The resulting PEC curve is nearly identical to before the motor swap!

Then I took a test image at 42.4 seconds sub-exposures, but the poor tracking continues and I got many trailed images.

Bottom line: the tracking problem is not with the motor / gear box.
We now suspect the problem is with the worm

Opened the observatory at 9:30pm, cooler at 14°C, some haze, no wind, full moon.
The purpose of this session was to try PEMPro to improve tracking and guiding.  I was learning to use the application "on the fly" so things moved very slowly.

I was able to get the telescope and ccd camera connected to the software on the first try.  The calibration process took a while because I was not familiar with the procedure, and the fact that during calibration CCD images are not displayed (as they are with Envisage or PHD guiding).

Next I tried PEC training but I left the previous PEC data on the scope.  After completion I tried to combine the two data sets, but got an error about data not being in synch. So I moved on and re-set the PEC and started a brand new PEC traning session.  I got a PE curve that was very different from the August 17 curve and also the data seemed much too smooth.  Anyhow, I uploaded that PE data and tried to take an image. It was a disaster with huge trails and double star images!

The next day Andrew Johansen explained to me that the PEC data I collected was out of phase!
That was my error because I failed to properly synch the phase at the start of the PEC training session. By putting the curve "back into phase" the curve was nearly identical to the August 17 PE data.

Opened the observatory in the early evening and began getting the equipment ready around 8:45pm. Quite clear, cool at 13°C, some wind. The purpose of this session was to try to improve PEC using PEMPro.

The setup was the 10-inch at F6.3 with the DSI Pro II. After calibration I noted that the image scale was 1 arc-second per pixel.

I cleared the PEC and did a new training session, comprised of two cycles (24 min x 2).  The resulting  curve shows a PE of just 15.23 arc-sec peak to peak.  This is better than average for an LX200GPS mount. However, the problem lies in the steep slopes of the curve, which mean rapid transitions in PE.

Next I loaded the above PEC curve and did another training session, in an attempt to further reduce the PE. The resulting "curve" was very strange. It was a nearly straight line with a positive slope.  This did not make any sense and I was not sure what could have gone wrong.

I did further PEC work, but because it was based on the above strange "curve" none of it made much sense.

Opened the observatory at 8:30pm. Clear, 16°C, hazy, no wind. The purpose of this session was to do better PEC training.  I started the first training at 8:45pm while twilight was still in progress.

I ran several training sessions trying to reduce and refine the PE along the way.  Once again I got rather strange PE curves beyond the very first PEC run.  It appears that when doing a training session after clearing the PEC, I get very consistent and repeatable curves, but when I try to update or refine the curves further, it gives strange results. I do not know how to explain that.

In the early evening I showed my relatives a few things through the scope.  After they left I went back to the observatory to try some imaging and fiddle with PEC some more. The sky was quite clear, warm, and lots of mosquitoes.

The setup was the 10-inch at F6.3 with the DSI Pro II guided by the Orion 80ED with the DSI Pro at prime focus.

The first image was of M27 guided with Envisage at 0.5 sec guide exposures and correction gain of 0.5. Tracking and guiding seem better than usual, with about 50% good images from 42 sec exposures.  Eventually Envisage crashed.

Next I tried guiding with PHD Guiding. Guide exposure is still 0.5 sec, aggressiveness is 100 and hysteresis is 10. I disabled DEC guide corrections.  This time I got about 57% good images from 42 second exposures.

I tried another exposure with PHD Guiding with the same settings as above and this time I got about 68% good images.   Then I changed the guide exposure to 2 seconds and performance got worse, with only about 50% good images.  Looks like the shorter guide exposures work better.

Next I moved to NGC 891, a big edge-on galaxy.  Guide exposures of 1 sec and 2 sec did not yield good images. I then turned off PEC as a test, and I confirmed that PEC on does help.  Finally I went back to a guide exposure of 0.5 sec and got about 70% good images. Confirming that shorter guide exposures work better.

At 4:30am the Sky Quality Metre (SQM) reading was 18.1 to 18.57 depending where the Metre was pointing.

Opened the observatory at 8:45pm, clear, hazy, warm. The purpose of this session is to refine PEC and then try some imaging.

I loaded a known good PE curve from a few days ago and then started a new PEC traning session to try to reduce the PE.  I let it run for 6 cycles (24 min x 6) and watched the curve on the PEMPro screen.  The data made no sense as the lines were not parallel and showed lots of drift.

Frustrated with the above result, I fiddled with the alignment of the main scope and the guide scope, then I thought I'd try some imaging, but this time using a really short guide exposure, like 0.2 seconds.

The setup was the 10-inch at F6.3 with the DSI Pro II guided by the Orion 80ED with the DSI Pro at prime focus. Guiding with PHD, guide exposure 0.2 sec, DEC guiding off, all other PHD settings are default. I tried 60 second exposures and I got excellent results!

Next I tried the above settings on M15 and again, 60 second exposures were well guided!

Next I tried NGC 891 and again 60 second exposures were well guided.  I then tried 2 minute exposures and again, round stars!!!

Tonight was a major breakthrough for guiding.  The trick lies in making the guide exposures very short so that the mount has time to correct the very rapid PE transitions.

Opened the observatory at 8:45pm, clear, 23°C, some haze. The goal for tonight was to double check the good guiding from last night was not just a one-time lucky occurrence, but that it is repeatable.

With the same setup as above, I took 1 minute exposures and 2 minute exposures and nearly 100% of frames were good.  It appears my tracking and guiding problems are resolved!

Opened the observatory around 11:30pm, quite clear, 14°C, a little wind, 75% humidity. The plan for tonight is to get RGB images of NGC 891.  The Sky Quality Metre (SQM) is 18.5 to 18.7, which is about 0.2 better than usual.

The setup was the 10-inch at F6.3 with the DSI Pro II guided by the Orion 80ED with the DSI Pro at prime focus. Guiding with PHD, guide exposure 0.2 sec, DEC guiding off, all other PHD settings are default.

100% of frames have round stars!  Awesome. Here's an LRGB image of NGC 891.

Some other problems tonight:  I cannot seem to get dark frames that completely remove all hot pixels. There are always a few hot pixels left even though I took dark frames at the exact same temp as the light frames. Strange.  The flat frames I took don't quite remove all vignetting. This could be caused by improper flats, or maybe by sky glow / light pollution.  All the above problems can be mostly corrected by processing the image, but it's a lot of work!

to Sep. 7