Remote Planets, Uranus, Neptune and Beyond!
August 30, 2019. Fixed it. Was poor dark subtraction. The "constellation" was dithered dark pixels. After reprocessing, they went away. See below for final animation with an added observation from tonight.
August 29, 2019. I got another image of Pluto tonight to add to my animation. See below. I observe an interesting additional phenomenon tonight: a whole group of new objects of similar brightness appeared in the image that were not present in the images of the 25th and 27th. I know there is a lot of stuff out there, natural as well as manmade, but I suspect I got photobombed by several members of the constellation of Starlink satellites SpaceX put up back in May.
August 27, 2019. I finally got overlapping images of the region of the sky where Pluto is on two nights, tonight and two nights ago. below is an animated GIF of the overlapping regions of the two images. Pluto can be seen hopping from RA = 19h29m50s, Dec = -22°19'23" in Sagittarius at around 9:21 PM EDT on August 25 to its position of 19h30m42s -22°19'51" at 9:35 PM EDT on August 27, 2019. The distance moved was almost exactly 2 minutes of arc in the direction of 258° 04" 14" position angle.
Below is the image from the evening of August 25. Sorry about the mottled background, I evidently had a bad light leak in the tailpiece of the Schupmann, probably around the JMI reverse Crayford focuser. Very difficult to baffle (baffling, in fact!). I think I will replace it with a not-reverse Crayford from JMI which does not have the big gap around the drawtube.
Below is the considerably better result from the evening of August 27. The improvement was obtained by draping a "snood" of duvetyne cloth over the tailpiece and tucking it in all round so no light from computer screens could leak in. This image is a stack of 8 dark subtracted images of 30 seconds exposure (unguided). No flats used, was a disaster last time I tried it, probably because of the light leak.
The above chart was made with the aid of TheSkyX showing the movement of Pluto through Sagittarius from August 9 through August 15, 2019.
August 7, 2019. Cloudy tonight, no chance for more imaging of Pluto. Reworked my images from July 29, stackng all 31 of the ten second exposures after dark correction. The resut is shown below. Five near 14th magnitude stars are indicated and the predicted position in TheSkyX is also shown. I am confident that the near 14th magnitude dot to the left of TheSkyX position for Pluto is actually Pluto. North is up in this image.
July 29, 2019. Trying to capture Pluto. This is the first image in a series in which I hope to find Pluto as it is emerging from the Sagittarius star clouds of the Milky way and show its motion over the next few months. There is a tiny dot that looks about right for 14th magnitude very close to where Guide9 says it should be. If that is Pluto, it will skip along to the west. I think it should be in retrograde now. The larger blobs and the inverted PL symbol are from the Guide9 finder chart overlay. Click on the image to enlarge it so you can see the dot that might be Pluto and the arrows pointing to it. South is up in this animation.
February 16, 17, 2019. The above is my best image of Uranus to date. It is based upon 12 minutes of 251 ms exposures taken with the ASI290MM CMOS video camera fitted with a filter having a long pass cutoff at 850 nm and 2 minutes of 11 ms exposures taken with the ASI224MC one-shot color CMOS video camera and 1.5x Barlow lens. My 7.25" f/14 Schupmann Medial telescope was used for both sets of video data. The best 25% of the frames of each video were aligned and stacked in Autostakkert 2 and the final image composed in PhotoShop elements using the NIR image as luminance and the one-shot color image as chrominance. I believe the bright spot on the left side of the image is the north polar hood of Uranus. Terrestrial South is up in this image, and the north pole of Uranus is to the left.
Note that the NIR image (as well as the nirRGB image) is lower in resolution than the visible light image. This is because the average wavelength of visible light is around 500 nm whereas in the NIR bandpass it is about 900 nm. The Airy disk at 500 nm for a 7.25 inch aperture is about 0.75 sec arc in diameter while at 900 nm it is 1.23 arc second and the planetary disk size is only 3.45 arc seconds. We are certainly working at the limits of my little telescope! If I could get better seeing, the C1100EdgeHD scope would have Airy disks at those wavelengths of 0.49 and 0.81 arc seconds and the image would be considerably sharper. With the C14 it would be 0.39 and 0.64 arc seconds, however the probability of getting diffraction limited seeing for the 14 inch aperture is pretty much negligible at sea level in NJ.
February 16, 2019. I had been trying unsuccessfully to image the north polar hood of the planet Uranus. Using one-shot color cameras all I got was a featureless light blue disk. Hypothesizing that the blue color might be high altitude haze in the atmosphere scattering blue light, I reasoned that if I imaged in the near infrared, I might be able to penetrate to the level where the bright polar hood became visible. So, I took three 120 second videos of Uranus using the ASI224MC one shot color video camera coupled to the 7.25" Schupmann medial with a 1.5x Barlow lens. This combination delivers f/24. I then replaced the color camera and Barlow with the ASI290MM monochrome camera fitted with an 850 nm cutoff high pass filter. This gives me a bandpass from 850 nm out to the 1 micron cutoff of silicon photodetectors. I took another three 120 second videos with this setup. I had to use a shutter speed of 251 ms and a much higher gain for the NIR imaging compared with only 11 ms for the color imaging. And still got only 478 frames from each video in the NIR compared with 1356 frames from the color videos. I processed the videos using Autostakkert 2, keeping the best 25% of the frames from the color videos and the best 50% from the NIR videos. The individual stacked images were then combined in Photoshop using the NIR image as luminance and the color image as chrominance. Results from the three sets of videos is shown below. The top row are the color images from the ASI224MC, the middle raw are the NIR images from the ASI290MM and the bottom row is the result of using the NIR images as the luminance and the color images as the chrominance. The left side of the combined images is definitely brighter and that is where the north polar hood should be.
August 23, 2016 Beautiful clear night with well above average seeing. Got home from Jenny Jump remote site around 3:30 am and set up CPC-1100EdgeHD on Uranus using the ASI-1600MM and 3x Barlow. Took a set of 2000 FITS files of Uranus and a nearby single star, SAO109964, for deconvolution purposes. Sent them to Dave Rowe to try his bispectrum routine. I then took a one minute video of Uranus. Since seeing was good and I was using a lower focal ratio, I was able to use very short exposures. I processed this monochrome image and used it as the luminance for the image obtained on the 20th with the color camera. Composite result is above.
October 8, 2015. After finishing my double star program for tonight, I realized that Neptune was near the meridian and lined up on the distant planet, only 2.3 arc seconds in diameter at its distance of 2.7 billion miles. Not much to see at that distance.
Project for this coming summer. Catch Pluto in Sagittarius. It has passed the bulge of the Milky Way galaxy and should be relatively easy to image. Try with C1100EdgeHD with 0.7x reducer and the ASI-1600MM camera. Starfields below from the DSS show positions (purple crosses) at 1 am on June 21, 22, and 23 2019.