I finally had an opportunity to get some sky time after setting the CGEM back up on the pier and completion of the recent interior work at the observatory. The forecast was calling for clear skies, I was determined to get the drivers installed on my Windows 7 tower computer which I recently relocated to the observatory due to some keyboard issues on my laptop. My goal for the evening was to get the tower computer communicating with the telescope and cameras along with achieving my final polar alignment and park position for the telescope. If I had extra time, this would be spent grabbing some lights to test out my cables and guiding settings for my setup.
I went out around 3pm to download the 64 bit Evisiage drivers from the Meade website, only to find out the whole Meade website was down. I was a bit frustrated, but decided with the great forecast and observing opportunity to set my laptop back up and make do with an external usb keyboard and a stuck control key on the laptop. I knew I would experience some minor setbacks and was prepared to handle them. Luckily, I was able to operate with the laptop in a slightly limited capacity.
I came back out around 9pm and proceeded to do my two star alignment along with an additional two stars as part of the Celestron Two star alignment routine. During this time I aligned the Meade 80 mm APO scope along with my finder scope. The next step was my polar alignment routine which was quickly accomplished in under five minutes. Surprisingly, after the first adjustment my PA came in dead on: objects were staying centered in the FOV of my EP for 30 minutes without detection of drift. I quickly redid my two star alignment plus an additional two extra stars after completing the polar alignment. The CGEM appeared more than ready to take on imaging tasks.
The final step in my preparations was to attach my cameras to the telescopes. I attached the cameras and placed a Bahtinov mask on each OTA. A goto of a nearby bright star was then initiated, the object was almost perfectly centered in the FOV of the imager. I next opened up Nebulosity 2.4 in the frame and focus mode set for 5 second exposures, controlling the DSI IIIC attached to the main imaging scope, quickly achieving optimal focus while using the Bahtinov masks.
I opened up PHD guiding software and established communications with the SSAG attached to the Celestron Edge 800 OTA. Once again, I found the star was nearly perfectly centered in the FOV of the guiding camera, focus was quickly achieved. I was very pleased with my initial results and surprised to find I had much more time now to capture some photons.
I decided a test run of imaging was in order, why waste time at this point on an easy target. I looked at my charts and decided to enter M33 into the control pad, the telescope quickly slewed to where it thought M33 should be in the sky, a quick glance and I knew it was pointing in the right area of the sky. I programmed in one 60 second exposure to see if M33 was indeed in the FOV. I saw M33 appear before my eyes a little bit left and up from center, more than acceptable.
I turned on PHD to see what I had available for guide stars, I was a bit surprised to find nothing in the FOV which would work. I slowly moved M33 down in FOV and to the right a bit using a bright star as a guide using 8 second exposures until I saw a nice guide star appear in the PHD window. M33 was still framed well, it was time to see if PHD would calibrate for me. I changed a few settings in the brain settings, I was using the F/10 telescope to guide with which is bit more sensitive to guiding settings. I hit the button to begin the calibration process, PHD quickly calibrated in under two minutes and appeared to be guiding very well.
I decided right away not to waste time on short exposures. I programmed Nebulosity 2.4 to take five images of 8 minutes duration each, setup the file directory path, and hit the start button. The time spent waiting for the results of the first exposure seemed like an eternity. After the long wait, M33 appeared in front of my eyes with nice round stars, the first exposure was a great success and the image showed a large amount of hidden data. I waited what seem like an eternity for the second exposure to show itself, a bit surprised when I saw nothing but white amp glow across the whole screen. I figured it may be a glitch and waited on the third and fourth exposure, both of which came out same as the previous images, nothing but ampglow. I decided at this point of time to end the image sequence. I had an issue with the DSI which I needed to solve.
The Meade DSI ccd imagers are known to require the max amount of power that a usb port can supply, they are very fussy and require high quality cables along with short runs. I plug my DSI IIIC into a powered usb hub to allow for ample supply of power to the imager. I inspected the cable only to find I had attached a smaller gauge usb cable, not the one I normally use. I changed this out, and to my relief the imager was functioning again, unfortunately precious time was wasted and M33 was high in sky at blindspot in my dome.
I decided at this point of time to jump down in the Eastern sky towards M45 Pleiades. The CGEM goto once again put the object nicely in the FOV on my imaging camera. I recalibrated PHD in under two minutes then setup the sequence to capture six 90 second exposures of M45. Each exposure had nice round stars, all very useable. I quickly placed my darkening towel over the scope and programmed in four darks for 90 second exposures and hit the start button. While the scope was busy taking the darks I ran into the house to grab a few beers for a refill. When I came back out the last of the dark frames was just finishing up.
I took time at this point to inspect the one lightframe on M33, the data looked great, but I saw what appeared to be dust motes across the image when I performed a quick stretch on image to see the hidden data. I pulled open one of the M45 lights, to confirm that both images had the same exact dust motes showing. It was nearly 412 am I decided the night was successful, I had accomplished my main goal of polar alignment along with establishing a hibernate position for the telescope. That I had opportunity to grab some lights was merely icing on the cake. The dust motes were a huge disappointment, but not the end of the world. I will clean the DSI filter, even more reason to start taking flat frames in the future, which deal with these type of issues along with gradient issues.
I did quick stack and process of the M45 data, nothing spectacular from processing side, I could not stretch image much to reveal the nebulosity without the dust motes becoming very apparent in this test image. I used Deep Sky Stacker to stack and align the lights and darks, then did quick process in Photoshop Cs3+ with small amount of noise removal applied to the image. I undercompensated a bit on the red and green channel data, but thought I would post this image here to share the guiding results. The second image below is the 8 minute exposure of M33. The amount of data hidden in M33 looks great. The nice round stars showing in this single unprocessed frame let me know that guiding is working great. I am confident next time out I will grab some solid data to work with. I will work on removing the dust motes from the imager before my next imaging session. Overall, the night was a great success.
M45-Six Lights(frames) of 90 secs. each. 9 min of data total. Very quick process in Photoshop Cs3+ to highlight guiding. Same dust motes are in this image if stretched more as in the m33 single lightframe.
- M33 One 8 min exposure. No processing done. Small stretch applied to this data. This image shows nice round stars(excellent tracking and guiding), lots of data in this single 8 min exposure can be brought out when combined with many more single exposures like this. Notice the dust motes which appear as black blotches in image. For non imagers reading, this is one lightframe, A final image is processed from many single frames(stacked and aligned) like this single frame. The technique of stacking and aligning the exposures reduces grain noise, enhances colors, and reveals fine details such as nebulosity in the image.
Same 8 min exposure(raw data) of M33. I stretched single exposure little bit more to reveal the data, dust motes are very evident. The DSI IIIC needs a good cleaning. More reason to start using Flats in future. I am very happy with the tracking and guiding results.
