David Mathre Photography

Astrophotography

  • The continuing observations of comet C220P/McNaught with my Vespera telescopes. After several cloudy days and nights, the ClearNightSky forecast looked good for two or three nights. I updated the manual target coordinates (RA/Dec: 03h 09m 01s; +09° 19′ 20″) for the comet in Singularity and started overnight observation plans for the Vespera telescopes.

    The head of the comet is green, and the tail is nearly 1° long. According to the Comet Observers Database (COBS) the visual magnitude of the comet was 9.9 for the night.

    The following slideshows include the straight out of the telescope (SOOT) images and images processed with PixInsight . For scale, I’ve included annotated and cropped images (0.5° and 1.0° FOV width). All of the images including the 16-bit RAW/TIFF files are available on my PhotoShelter site (20260824). Click on the i below the slideshow to view the image captions.

    Vespera 1 Telescope

    Vespera Passengers Telescope

    Vespera 2 Telescope

    Vespera 3 Telescope

    Vespera Pro 1A Telescope

    Vespera Pro 1B Telescope

    Vespera Pro 2 Telescope

    Links to my previous observations of comet 220P/McNaught: 20260606, 20260609, 20260616, 20260810, 20260811, 20260815, 20260816, 20260819, 20260820

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  • My observations of comet C220P/McNaught continue. The forecast from ClearNightSky looked promising. I set up the Vespera telescopes with an overnight plan that included different manual target observation settings. The new coordinates for the comet (RA/Dec: 03h 02m 55s; +09° 27′ 45″) were updated in Singularity.

    The skies remained clear much of the night permitting the telescopes to collect better images of the comet than the previous night (19-August). The comet tail is long and you can detect some curvature. According to the Comet Observers Database (COBS) the visual magnitude of the comet was +9.5 for the night.

    The following slideshows include the straight out of the telescope (SOOT) images and images processed with PixInsight or Sky Color Studio. For scale, I’ve included annotated and cropped images (0.5° and 1.0° FOV width). All of the images including the 16-bit RAW/TIFF files are available on my PhotoShelter site (20260820). Click on the i below the slideshow to view the image captions.

    Vespera 1 Telescope

    Vespera Passengers Telescope

    Vespera 2 Telescope

    Vespera 3 Telescope

    Vespera Pro 1A Telescope

    Vespera Pro 1B Telescope

    Vespera Pro 2 Telescope

    Links to my previous observations of comet 220P/McNaught: 20260606, 20260609, 20260616, 20260810, 20260811, 20260815, 20260816, 20260819

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  • During my observations of comet 220P/McNaught on 10-August and 16-August, I noticed a brighter area at the center of the image’s background gradient, where the comet is centered and its tail is partially obscured. The issue is more pronounced with newer telescopes, including the Vespera 3, Vespera Pro, and Vespera Pro 2. It appears on the tablet screen during the observation and in the final JPG output files. Processing the images with Sky Color Studio minimizes but does not eliminate the center gradient. I don’t see the gradient when processing the RAW/TIFF files with PixInsight.

    Comet 220P/McNaught viewed from my backyard with a Vespera Pro 2 Telescope. Frames: 0068; total exposure time: 1340 sec.
    Comet 220P/McNaught viewed from my backyard with a Vespera Pro 2 Telescope. Frames: 0068; Total exposure time: 1340 sec. Manual target settings. Object type: nebula; exposure: 20 sec; gain 15 dB

    To further investigate the issue, I’ve started running multiple observations of the comet each night with different observation parameters. In addition to the target’s RA/Dec position, Singularity’s advanced mode for Manual Targets has several options: Target type (nebula, galaxy, cluster); Individual exposure time (1-30 sec); Gain (0-27 dB). For tonight’s observations I created Manual Targets with target type: nebula; varied the exposure time and varied the gain. The modified manual targets were added to the overnight plans for the different Vespera telescopes.

    The results are shown in the unedited, “straight out of the telescope” (SOOT) JPG images below, and are available in my PhotoShelter gallery. Click on the i below the slideshow to see the caption with the Manual Target parameters.

    The center gradient is not present on the Vespera 1 images but is visible with the other telescopes. Frame exposure time and gain didn’t seem to make much difference. There were a few observations where I adjusted the mosaic size, and you can see the background is darker in the center of the image where the comet is located. I’ll investigate mosaic size next time. However, it is not the best option when doing shorter observations when there is not enough time to complete multiple exposures over all sections of the mosaic — and the comet is moving relative to the background star field.

    Vespera 1 Telescope

    Vespera Passengers Telescope

    Vespera 2 Telescope

    Vespera 3 Telescope

    Vespera Pro 1A Telescope

    Vespera Pro 1B Telescope

    Vespera Pro 2 Telescope

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  • The ClearNightSky forecast looked marginal for the night, but it looked like there may be some clear skies when comet C220P/McNaught would be visible. I updated the manual target coordinates (RA/Dec: 03h 01m 24s; +09° 29′ 09″) for the comet in Singularity and started an overnight observation plan. My Vespera Passengers just returned from France after warranty service so was also set up for observing the comet.

    The skies were clear long enough for the telescopes to get some images of the comet. The comet tail appears to be getting a bit longer. According to the Comet Observers Database (COBS) the visual magnitude of the comet was 9.4 for the night.

    The following slideshows include the straight out of the telescope (SOOT) images and images processed with PixInsight or Sky Color Studio. For scale, I’ve included annotated and cropped images (0.5° and 1.0° FOV width). All of the images including the 16-bit RAW/TIFF files are available on my PhotoShelter site (20260819). Click on the i below the slideshow to view the image captions.

    Vespera 1 Telescope

    Vespera 2 Telescope

    Vespera 3 Telescope

    Vespera Pro 1A Telescope

    Vespera Pro 1B Telescope

    Vespera Pro 2 Telescope

    Vespera Passengers Telescope

    Links to my previous observations of comet 220P/McNaught: 20260606, 20260609, 20260616, 20260810, 20260811, 20260815, 20260816

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  • The ClearNightSky forecast looked good for the night. I’ve not had many good observation nights in a row all spring and summer. I set up the Vespera telescopes to observe several targets including comet 220P/McNaught. Since the comet is moving relative to the other stars, every night I need to update comet coordinates (RA/Dec 02h 57m 06s, +09° 31′ 49″) in Singularity as manual targets for each telescope. The manual target settings also included type: nebula; exposure time: 10 sec; and gain: 20 db. I then set up the overnight observation plans in Singularity for each Vespera telescope. After observing the other targets, the first comet observation started at ~02:30. I’ve posted time-lapse videos of the overnight sky (180° and 360°) 20260816.

    All of the telescopes were able to make several observations of the comet. Other than the position in the sky, the comet hadn’t changed much since the previous night (15-August-2026). It still has a bright green head, dust cloud, and tail. According to the Comet Observers Database (COBS) the visual magnitude of the comet was 9.1 for the night.

    The following slideshows include the straight out of the telescope (SOOT) images and images processed with PixInsight or Sky Color Studio. For scale, I’ve included annotated and cropped images (0.5° FOV width). All of the images including the 16-bit RAW/TIFF files are available on my PhotoShelter site (20260816). Click on the i below the slideshow to view the image captions.

    Vespera Classic Telescope

    Vespera II Telescope

    Vespera III Telescope

    Vespera Pro 1A Telescope

    Vespera Pro 1B Telescope

    Vespera Pro 2 Telescope

    The unprocessed (SOOT) jpg images have a significant center of the image background gradient that obscures the tail of the comet. I set the BalENS (Enhanced Imaging Technology) mode for Vespera Pro (1A) to “classic”, Vespera Pro (1B) to “Recommended” and Vespera Pro 2 to “Recommended”. I don’t see much difference in the background center gradient in the unprocessed (SOOT) jpg images. BalENS is only supposed to impact the screen and the saved JPG images created by the telescopes. Processing the images with Sky Color Studio reduced but did not eliminate the center gradient.

    I was able to eliminate the center background gradient issue with PixInsight using the Automatic Background Extraction process. The Gradient Correction process also works. My workflow with PixInsight also includes the Spectrophotometric Photo Callibration for white balance and NoiseXterminator for noise reduction.

    Links to my previous observations of comet 220P/McNaught: 20260606, 20260609, 20260616, 20260810, 20260811, 20260815

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